Wednesday, 21 February 2018

" a parental history of T1D was associated with a 29% increased risk of being diagnosed with ADHD"

T1D mentioned in the title of this post - "a parental history of T1D was associated with a 29% increased risk of being diagnosed with ADHD [attention-deficit hyperactivity disorder]" - refers to type 1 diabetes. This is an autoimmune condition where the body's own immune system attacks 'self' and, in this case, leads to serious problems with the production of insulin with onward effects on blood sugar (glucose) levels.

The findings reported by Jianguang Ji and colleagues [1] observed something of a *correlation* between parental history of type 1 diabetes and offspring risk for ADHD. Based on the analysis of one of some of those splendid Scandinavian population registries - this time based in Sweden - researchers found upwards of 15,000 children "born after their parents were diagnosed with T1D." Bearing in mind previous research had hinted that a parental medical history of various autoimmune conditions might elevate the risk of offspring ADHD (see here), they looked-see whether "a family history of type 1 diabetes (T1D) is associated with an increased incidence of attention deficit hyperactivity disorder (ADHD) in offspring." It appeared to be so.

When taking into account various other potentially confounding variables, authors noted an overall increased risk (hazard ratio) to offspring which also appeared to fluctuate depending on whether mum or dad was diagnosed with T1D, albeit not statistically significantly so. Having said all that, this study is still one of correlation and not necessarily causation...

'Why?' is the question still to be answered. Why would an autoimmune condition with seemingly little neurodevelopmental 'connection' in terms of behavioural symptoms, raise the risk of something like ADHD in offspring? I might add that a similar question is being asked across quite a few other developmental diagnoses (see here for example). I have some ideas (see here) outside the obvious focus on blood glucose, but some solid research and science really needs to follow.

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[1] Ji J. et al. Type 1 Diabetes in Parents and Risk of Attention Deficit Hyperactivity Disorder in Offspring: A Population-Based Study in Sweden. Diabetes Care. 2018 Jan 26. pii: dc170592.

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Tuesday, 20 February 2018

One percent of Chinese middle school students "met the definition of CFS"

CFS mentioned in the title of this post refers to chronic fatigue syndrome otherwise known as myalgic encephalomyelitis (ME). The question of how prevalent CFS/ME might be in various groups - particularly young people - was tackled in the paper published by Jieyao Shi and colleagues [1] (open-access available here). This continues some previous research chatter on this topic (see here) including the important differentiation of chronic fatigue syndrome from just 'chronic fatigue' (see here)...

So, what was done? "This cross-sectional survey enrolled 18,420 middle-school students aged 10 to 18 years (mean 14.9 ± 1.68) who were selected randomly between September 2010 and January 2011 from 25 junior- and senior-middle schools in Suzhou, China at a ratio of 1:1 with respect to the gender and grade." That's quite a big starting participant group in anyone's book; although eventually whittled down ever so slightly to 18,190 after dropping those who did not complete the study instruments properly for example.

As to the question of defining CFS (a *real issue* down the years), we are told that two schedules were used: "the US CDC-94 definition of CFS" otherwise known as the Fukuda criteria, and the "Chaldea fatigue scale (CFQ)" which is an error;  it should read the Chalder Fatigue Scale. A diagnosis of CFS was decided on the basis of both schedules yielding a positive result and "at the same time the school health workers excluded the fatigue symptoms that may be associated with other medical conditions after reviewing their yearly routine physical examination records." Where CFS criteria were not fully met, a diagnosis of chronic fatigue (CF) was given.

Results: "The prevalence of CFS and CF in this study was 0.9% and 12.0%, respectively." Nothing particularly novel there given other data that has discussed similar CFS frequency figures present in similar age-groups (see here). The idea that chronic fatigue not CFS is present in around 1 in 10 young adults is rather startling...

I was also quite interested in another observation made by Shi et al: "Other than fatigue, muscle pain, joint pain, difficulty in concentration, headache, and sore throat as specified in the CDC-94, despondency, irritability and being afraid of going to school were the most important symptoms of CFS in the middle-school students investigated in this study." Despondency, irritability and being afraid to go to school are again, probably not unexpected when it comes to CFS/ME in this age-group. I'm minded to suggest that such characteristics are likely 'reactive' symptoms to the presence of CFS/ME over and above having any significant aetiological input. If for example, you've been bed-bound, struck down by months or years of not being able to do all the things that teenagers and young adults like and want to do, it's very possible that you probably wouldn't feel your best and could, in the longer-term, be prone to developing something approaching depressive symptoms. That doesn't mean that depressive symptoms or actual depression caused your CFS/ME or even that depression is a core part of your CFS/ME; merely that depression joins the clinical presentation as per other instances in medicine [2]. As for the observation about being afraid to go to school, well, one only needs to look at other conditions where school refusal has been noted (see here) to perhaps understand some important hows-and-whys.

"Our study shows that CFS is prevalent among Chinese teenagers, and requiring proper intervention and treatment." That was the conclusion reached by Shi and colleagues, and with it the next obstacle to face: what is 'proper intervention and treatment'? Importantly too, will this manage to leave out the psychobabble explanations that have pervaded Western ideas on CFS/ME? Will it instead concentrate on the idea that CFS/ME is a multi-faceted organic illness - with probably more than one aetiology [3] - displaying both physiological and psychological side-effects?

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[1] Shi J. et al. Chronic fatigue syndrome in Chinese middle-school students. Medicine (Baltimore). 2018 Jan;97(4):e9716

[2] Tang PL. et al. A Systematic Review and Meta-Analysis of Demoralization and Depression in Patients With Cancer. Psychosomatics. 2015 Nov-Dec;56(6):634-43.

[3] Mørch K. et al. Chronic fatigue syndrome 5 years after giardiasis: differential diagnoses, characteristics and natural course. BMC Gastroenterology. 2013;13:28.

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Monday, 19 February 2018

Behind the headline: "Autism: Scientists take 'first steps' towards biological test"

Monday 19th February 2018. I opened my computer up early in the morning and lo and behold, headlines about autism appeared, as exemplified by the BBC article titling this post: "Autism: Scientists take 'first steps' towards biological test." A cold shudder ran down my body as memories of previous 'Super-parenting' improves children's autism and similar headlines sprung to mind and with it, the question of whether big claims were being made...

The paper behind the headlines this time around was from Attia Anwar and colleagues [1] (open-access) and I have to say at first sight I was really rather interested in the specific topic under investigation. Namely: "to explore the diagnostic utility of proteotoxic biomarkers in plasma and urine, plasma protein glycation, oxidation, and nitration adducts, and related glycated, oxidized, and nitrated amino acids (free adducts), for the clinical diagnosis of ASD [autism spectrum disorder]." Interested because the words 'amino acids' (an area of interest to this blog) were mentioned and also that their description of using "stable isotopic dilution analysis liquid chromatography-tandem mass spectrometry" plays to the analytical chemistry nerd that I've seemingly become down the years.

So, bearing in mind the Anwar paper is open-access, what were the hows-and-whys of this 'first steps' research? Well, the initial premise was a sensible one as words like '3-nitrotyrosine (3-NT)' are mentioned following other research noting this compound with some autism in mind (see here). It all ties into the process of oxidative stress and neuroinflammation that are becoming more readily accepted to be part-and-parcel of at least some autism (see here and see here). Researchers set out to see if they could detect some important compounds involved in the process of protein homeostasis (amino acids are the building blocks of protein) and whether, by using the process of machine learning on the derived data (see here for another example of this being applied to autism), the possibility of a diagnostic test for autism might be forthcoming from such work. Yes, this was another example of metabolomics being applied to autism research (see here and see here) and seems to continue a research journey from members of this authorship group [2].

Urine and plasma samples were the chosen analytical media, as authors report on the recruitment of 38 children diagnosed with an ASD and 31 not-autism controls. Yet again, the words 'healthy controls' are used to denote not-autism; something that we really shouldn't be seeing in this day and age. I'd also, by the way, say the same things about the term 'neurotypical' too (see here). The autism group did seem to have quite an extensive diagnostic work-up as both ADOS and CARS scores are presented. Spot blood and urine samples were provided by all and metabolomic analysis was begun...

Results: bearing in mind the significant complexity of both urine and plasma samples when it comes to the presence of small molecules and metabolites, the use of that mass spec method made short work of detecting the glycation markers indicated for study. I note also authors also provide some results on various amino acids in both urine and plasma that is, I think, rather important.

The first thing that struck me was the authors use of a compound called creatinine to correct for sample strength and dilution. I'd like to think I know a thing or two about creatinine (urinary) in relation to some autism on the back of a bit of published research a decade or so back [3]. Our conclusion then and also in some other independent work since (see here) is that caution is required when using creatinine as a corrector with autism in mind...

Having said that, a few findings are noteworthy: "we identified changes in plasma protein AGE [advanced glycation endproductsand oxidation adducts, increased CML [Nε-carboxymethyl-lysine], CMA [Nω-carboxymethylarginine], and DT [dityrosine] and decreased 3DG-H [3-deoxyglucosone] in ASD." I'm not all too familiar with all of those compounds listed but going back to my observation on oxidative stress being something pertinent to some autism [4], I think there are some important connections to be seen. I note also that at least one of the findings - increased DT residue content of plasma proteins - might also provide a role for those trillions of wee beasties that call us home, the gut microbiota. Mention of the gastrointestinal (GI) tract in the context of autism is likely not to sit well with some people, despite multiple evidence of involvement for some in both a functional sense (see here) and also at a more biological level (see here).

Then to the headline maker: "Algorithms to discriminate between ASD and healthy controls gave strong diagnostic performance with features: plasma protein AGEs—CML, CMA—and 3-deoxyglucosone-derived hydroimidazolone, and oxidative damage marker, DT. The sensitivity, specificity, and receiver operating characteristic area-under-the-curve were 92%, 84%, and 0.94, respectively." Those sensitivity and specificity stats aren't bad at all. They are certainly on a par with other 'classification' attempts with autism in mind, such as when cortisol and a suite of cytokines got the same analytical treatment for example (see here). The trouble is that such stats are based on a relatively small sample size and indeed, children aged between 5-12 years old. Given that many children (but not all) are diagnosed quite a bit earlier than 5 years of age, one has to wonder how relevant any biological test might be at such a later age. One is left feeling that perhaps the discrimination analysis part of the Anwar paper should have perhaps been left until replication on an independent cohort with a larger sample size was carried out, and perhaps relying on more than one testing occasion.

I was also a little bit 'put out' that I couldn't find any 'limitation' discussions in the paper by Anwar et al. There was lots of chatter about how this, that and t'other might relate to biological processes pertinent to some autism but in the discussion section there was very little about what could be wrong with the results as they stand (e.g, small sample sizes). In the current age also when autism is more and more being talked about as NOT being a stand-alone diagnosis (see here) and indeed, probably is a more plural diagnosis ("the autisms"), it is always worthwhile mentioning how any obtained results might have to be framed in those contexts. Yes, authors did have exclusion criteria for study entrance: "Subjects with ascertained medical and neurological comorbidity were excluded, through a medical work up including electroencephalography (recorded during awake and sleep), cerebral magnetic resonance imaging, standard clinical and neurological examination, neurometabolic, and genetic investigations (including comparative genomic hybridization array, molecular assay for Fragile X and MECP2)" but autism pure might not be so typical in the real world [5].

Although some people have reacted quite strongly to the Anwar results, I do think this is quite a good study. No, as it stands, I don't think it can say that autism might be diagnosed on the basis of a urine and/or blood sample. Indeed, we've been here before (see here for example). But it does provide some welcome insight into some of the potential biology associated with at least some autism, and once again, champions the use of some really, really advanced metabolomic technology to provide potential systems biology insights into at least some autism...

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[1] Anwar A. et al. Advanced glycation endproducts, dityrosine and arginine transporter dysfunction in autism - a source of biomarkers for clinical diagnosis. Molecular Autism. 2018; 9: 3.

[2] Anwar A. et al. Quantitation of plasma thiamine, related metabolites and plasma protein oxidative damage markers in children with autism spectrum disorder and healthy controls. Free Radic Res. 2016 Nov;50(sup1):S85-S90.

[3] Whiteley P. et al. Spot urinary creatinine excretion in pervasive developmental disorders. Pediatr Int. 2006 Jun;48(3):292-7.

[4] Rossignol DA. & Frye RE. Evidence linking oxidative stress, mitochondrial dysfunction, and inflammation in the brain of individuals with autism. Front Physiol. 2014 Apr 22;5:150.

[5] Gillberg C. & Fernell E. Autism plus versus autism pure. J Autism Dev Disord. 2014 Dec;44(12):3274-6.

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"A greater understanding of ASD-related violence risk is needed to combat stigma"

This is another one of my long posts, so please, bear with me.

The topic of violence is always an emotional one. I know that even to mention the word 'violence' in the context of any label/diagnosis/condition/group carries the risk of making some people believe that there is some sort of generalisable connection. No smoke without fire eh? And one only needs to look at another label to see how a link with violence and by inference, 'dangerousness' has left a deep and long-lasting mark (see here) that continues today. So we're stuck between a rock and hard place: to talk about something and the risks attached in doing so, or just leave it, let people make their own judgements...

I've discussed quite a few uncomfortable topics on this blog down the years in light of various peer-reviewed research publications. I'm not one for shying away from calm and proportionate discussion where science - peer-reviewed science - has some vitally important input. In that context, I continue my discussions on the topic of violence and autism (see here). By doing so, I'm not making any sweeping generalisations. I'm not making any wild claims. I don't offer any brilliant insights into this topic. I'm just following the science and keeping emotions as far away from such cold, objective science as possible.

But there is a message before I continue. A message to those who might, in light of various media headlines, make some snap judgements about some of the people in your community. The message is simple: violence, in all it's forms, is not inherent to any one group. No-one is violent because of generalisations about who they are, whether on the basis of age, race, socio-economic circumstances or anything else. There are typically reasons for violence, and in many cases they're complicated. By saying all that, I'm not trying to talk down the very real effects that violence can have on individuals, families and society in general and the strong need for justice and more importantly, prevention. Just that seemingly apparent correlations and simple answers rarely provide an accurate insight into the particular hows-and-whys of violence and violent acts...

So today I'm talking about the paper published by Jill Del Pozzo and colleagues [1] who "provide a comprehensive review of the literature bearing on the relationship between ASD [autism spectrum disorder] and violent behavior." This is a timely publication because I'm sure many people have seen the word 'autism' being used among the coverage of a quite horrendous act recently. Indeed, even Del Pozzo et al allude to other similar attention: "Over the last decade, there has been increased media attention focused on the relationship between ASD [autism spectrum disorder] and violent behavior due to a number of school shootings and high-profile criminal cases involving offenders with alleged ASD diagnoses."

Perhaps I need to mention that the word/description 'violence' covers a lot of ground. It of course covers violence against others, whether on an individual or collective basis, but importantly, also covers violence in many other forms including against oneself in the form of self-injury and/or self-abuse. Most media coverage of violence covers violence against others. But I'd wager that violence against oneself is the predominant form of violence in many circumstances minus any big headlines...

Del Pozzo et al set about providing a "comprehensive review of the literature" on autism and violence. Following their surveying of the current peer-reviewed research literature in this area, the authors concluded that whilst a diagnosis of autism is by no means protective of someone committing a violent act, there is generally more peer-reviewed scientific support for the idea that "ASD does not cause violence" over and above the sometimes negative media portrayals of the label in this context (see here). A welcome conclusion it has to be said, and one that needs to be circulated widely; but again, minus any sweeping generalisations and bearing in mind that science is all about probability not absolutes.

There are caveats to the statement that 'ASD does not cause violence' insofar as the multiple observations that autism typically does not exist in a diagnostic or social vacuum (see here), and how various factors (environment, psychiatric comorbidity, criminality) can potentially elevate the risk of violence for some people. All of this is not about passing the diagnostic buck (see here) as some people quite unceremoniously have decided to do, but needs to be mentioned; particularly in light of these days where 'autism plus' [2] is more typically the norm (see here) over and above the label of autism existing as some sort of stand-alone diagnosis. The pertinent question therefore may not necessarily be one of 'does autism cause violence?' but rather what role autism may or may not play [3] when it comes to violence, taking into account an often very complicated, very individual clinical picture. I say this also acknowledging that a diagnosis of autism is not some 'magical status' automatically reserved only for 'good people' (see here); just as any other behavioural/psychiatric label does not similarly distinguish between 'good' and 'bad' people.

As per the title of this post utilising a quote from Del Pozzo and colleagues - "A greater understanding of ASD-related violence risk is needed to combat stigma" - there is a pressing need to further understand how and why violence can/does occur for some alongside the label of autism or rather autism plus. Whether as part of the often nebulous term that is 'challenging behaviours' (see here) or in other related contexts (importantly also including that self-aggression angle), trying to answer such how/why questions can only be of benefit to all concerned. Indeed, alongside another quite sweeping generalisation made by Del Pozzo et al that: "Violence results from undetected or untreated third variables (e.g. psychosis)" and "Individuals with ASD have an elevated risk of psychosis", various lessons continue to be learned [4] (see here also) albeit stressing how complicated any relationship is likely to be [5]. As I mentioned before, easy answers are not likely to forthcoming.

Finally, I want end by again introducing the concept of 'vulnerability' in the context of autism into proceedings. I'm not specifically talking about vulnerability to various comorbidity that 'probably' influence the presentation of violence in the context of autism, but rather vulnerability in more general terms (see here). The writings of Tom Berney [6] provide some particularly insightful details on such vulnerability in relation to violent and other offending acts within the context of some autism or rather some 'autism plus'. Such vulnerability issues stress how, minus hype or sensationalism or indeed any calls for censorship in this most delicate area, investigations need to continue and sensitively continue without stigmatising and without further disadvantaging an already quite disadvantaged community...

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[1] Del Pozzo J. et al. Violent behavior in autism spectrum disorders: Who's at risk? Aggression and Violent Behavior. 2018. Jan 31.

[2] Gillberg C. & Fernell E. Autism plus versus autism pure. J Autism Dev Disord. 2014 Dec;44(12):3274-6.

[3] Allely CS. et al. Violence is Rare in Autism: When It Does Occur, Is It Sometimes Extreme? J Psychol. 2017 Jan 2;151(1):49-68.

[4] Långström N. et al. Risk factors for violent offending in autism spectrum disorder: a national study of hospitalized individuals. J Interpers Violence. 2009 Aug;24(8):1358-70.

[5] Bell V. et al. A symptom-based approach to treatment of psychosis in autism spectrum disorder in October 2017. BJPsych Open. 2018 Jan;4(1):1-4.

[6] Berney T. Asperger syndrome from childhood into adulthood. Brit Journal Psych Advances. 2044; 10: 341-351.

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Saturday, 17 February 2018

The 'oral microbiota' and autism: the power of a spit sample

Although not everyone's cup of tea there's a lot that can be learned from a humble spit (saliva) sample. Buccal epithelial cells from saliva samples provide a medium for the collection and analysis of DNA for example, and alongside, make for a much less invasive collection method than DNA capture from blood samples for example. Saliva also has it's own metabolome, meaning that one can potentially get quite a bit of information on quite an extensive library of small molecules linked to various genetic and biological processes.

Now add the oral microbiota to the list and, as per the findings reported by Yanan Qiao and colleagues [1], how the oral cavity (i.e. the mouth) is home to a complex network of bacteria and relations that might provide some important clues pertinent to various diagnoses.

Autism was the particular diagnosis in the research spotlight this time around, as authors "collected samples from two distinct intraoral habitats, including saliva and dental plaques, in children with and without ASD [autism spectrum disorder]." Analysing over 100 samples provided by 32 children with ASD and 27 not-autism controls, a few interesting things were noted in the results published by Qiao et al.

Bearing in mind this was a cross-sectional study which relied on a 'snapshot' sample over only one testing occasion, authors reported that: (a) data on bacterial richness and diversity showed no significant differences in salivary samples across the groups, but a difference was reported based on examination of those dental plaque samples; (b) "the phylum Proteobacteria was more abundant in ASD patients (both in salivary and dental samples) compared to controls" whilst other phyla predominated in controls; (c) "increased amounts of potential pathogens, including Haemophilus, Corynebacterium, Cardiobacterium, Kingella, Streptococcus and Rothia, were observed in ASD patients" some of which correlated with the measurement of the severity of autism (via parental report on the Aberrant Behavior Checklist (ABC) questionnaire); and (d) "diagnostic models based on key microbes were constructed, with 96.3% accuracy in saliva."

Of course, there is still some way to go in this research area, not least starting with independent replication of the Qiao results perhaps also relying on multiple samples provided across a range of times and situations. Y'know, assuming that medication for example, could be part and parcel of the profile with autism in mind and indeed remembering that autism as a stand-alone label is probably less like 'real-life autism' than many people realise (see here). I'm also a little unsure as to why the Aberrant Behavior Checklist (ABC) was employed "to preliminarily evaluate the severity of ASD" when both so many controls were employed for inclusion/exclusion on the study and so many other more 'autism-specific' instruments are quite freely available (see here for one example). There are things that could have been done differently for sure...

But, this is a good first attempt. It puts the oral microbiome on the research map with autism in mind, added to the more well-known relation: the gut microbiome (see here). It also provides us with a more generalised view of how the bacteria and various other miniature beasties around us, are probably more intricately involved in our lives than we ever previously thought possible...

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[1] Qiao Y. et al. Alterations of oral microbiota distinguish children with autism spectrum disorders from healthy controls. Scientific Reports; 8: 1597.

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Friday, 16 February 2018

Autism, mental health and 'sexual and gender minority' status

The findings reported by Rita George & Mark Stokes [1] piqued my interest recently, and their conclusion that various mental health issues over-represented in autism (see here and see here for examples) might not be just solely connected to the presence of a diagnosis of autism.

Yes, I know this sounds like common sense (see here), but as I've come to realise in relation to lots of diagnostic labels, assumptions very often precede actual (peer-reviewed) evidence.

Based on responses on the DASS-21 (which is fast becoming the go-to measure for the self-report of things like stress, depression and anxiety-like behaviours with autism in mind [2]), researchers compared depression, anxiety and stress scores for over 300 people with autism compared with over 250 "typically-developing individuals." Alongside, membership of a minority grouping in terms of sex and gender, e.g. non-heterosexual, was also thrown into the statistical mix. Results suggested that along with differences in DASS scores being more generally observed between the groups: "As membership to a minority group became more restrictive, mental health symptoms worsened... suggesting stressors added."

Such an investigation follows a scheme of work by this authorship group who, quite recently, also reported that within the same participant group(?), some 70% of those with autism "reported being non-heterosexual" [3]. I was quite taken aback by the high rate of non-heterosexuality reported in this study, bearing in mind that this data was derived from an on-line sample and may not be entirely representative of the full autism spectrum as a function of the use of self-report for example (see here). I might also add that focusing just on autism to the exclusion of some other potentially important comorbid labels [4] could be something that needs to be looked at in future investigations in light of other results on gender variance for example [5].

Minus however, any 'I told you so' sentiments, I have previously mentioned about how gender and sexual identity in relation to autism is both a research-rising area and can often have some quite profound implications for the person concerned (see here). We can um-and-ah about whether there is a 'connection' between autistic traits and sexual orientation (see here) or whether something like gender dysphoria is more or less likely in the context of autism (see here), but there is no denying that gender and sexual identity are variables that can and do potentially impact on mental health. In support of the George/Stokes findings, one need only look to the non-autistic focused research literature to see how various aspects of health-related quality of life for example, are seemingly influenced by variables such as sexual orientation [6] and how this potentially plays out over both childhood and into adulthood [7].

So when George & Stokes talk about: "Specialized care is recommended for this vulnerable cohort" there could be some pretty profound implications associated with timely and appropriate education and support taking into account sexual and gender identity in the context of autism...

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[1] George R. & Stokes MA. A Quantitative Analysis of Mental Health Among Sexual and Gender Minority Groups in ASD. J Autism Dev Disord. 2018 Jan 23.

[2] Nah YH. et al. Brief Report: Screening Adults with Autism Spectrum Disorder for Anxiety and Depression. J Autism Dev Disord. 2017 Dec 2.

[3] George R. & Stokes MA. Sexual Orientation in Autism Spectrum Disorder. Autism Res. 2018 Jan;11(1):133-141.

[4] May T. et al. Trends in the Overlap of Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder: Prevalence, Clinical Management, Language and Genetics. Current Developmental Disorders Reports. 2018. Jan 17.

[5] Strang JF. et al. Increased gender variance in autism spectrum disorders and attention deficit hyperactivity disorder. Arch Sex Behav. 2014 Nov;43(8):1525-33.

[6] Marti-Pastor M. et al. Health-related quality of life inequalities by sexual orientation: Results from the Barcelona Health Interview Survey. PLoS One. 2018 Jan 24;13(1):e0191334.

[7] Petterson LJ. et al. Sex, Sexual Orientation, Gender Atypicality, and Indicators of Depression and Anxiety in Childhood and Adulthood. Arch Sex Behav. 2017 Jul;46(5):1383-1392.

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Thursday, 15 February 2018

Walking as an intervention for good psychological health: number of steps or just enjoyment?

I'm once again returning to the topic of walking for health on this blog (see here) and some rather intriguing findings reported by Karen Hallam and colleagues [1] suggesting that adoption of a 100-day 10,000 steps a day program might have some bearing on aspects of mental and psychological health and wellbeing. But there's a bit of a twist...

The activity program in question was something called Stepathlon which, from what I gather, is a corporate initiative to promote health and fitness among employees. I might add that some employees in some occupations probably don't need such initiatives (see here). Various steps (pardon the pun!) are listed on the Stepathlon website including 'forming a team of 5 with your colleagues', getting yourself a pedometer or other fitness tracker that measures steps and then uploading your daily data on to their platform where it is compared with other groups across the world.

Hallam et al report results for nearly 2000 participants based on 'de-identified' data; also including participant reports based on the completion of the "short form of the Depression, Anxiety Stress Scales (DASS)" and the "Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS)." The various strands of data were analysed, correlated and the like.

Results: "The results of this study highlight some psychological and wellbeing benefits of being engaged in work based 10,000 step programs." The authors talk about observing a nearly 9% reduction in stress levels, 8% reduction in 'signs of depression' and a 5% reduction in anxiety when comparing pre-program with post-program data. They add: "This reinforces the benefits of this type of exercise regimen as playing a small yet significant role in improving mental as well as physical health."

But...

Things were not however completely straight-forward as the authors also talk about a "lack of a dose response" in terms of the number of steps completed and those psychological health and well being parameters being assessed. This could denote a few things: (a) participation in a program that encourages walking - walking in a group setting - may be beneficial irrespective of the number of steps that are actually taken, and/or (b) the wide variability in the number of daily steps taken over the course of the program - remember it lasted 100 days - scuppers any chance of getting meaningful correlation data between walking and psychological health. Indeed on that last point, authors mention that future work should really take into account things like the self-report nature of uploading daily activity levels and also the fact that within the sample there were "clearly individuals who were more active before commencing the program" and for whom such an intervention might not be all that effective given their already raised starting activity levels.

Still, I do think that this is a good piece of research that should encourage further investigation. Aside from the significant physical health benefits associated with getting more active, I'd also like to think that such a program could be further adapted for various groups, particularly when things like stress, depression and anxiety are considered a part of the clinical picture. Autism springs to mind as one such avenue for further study, based on various evidence [2] including result similarly using the DASS-21 tool. Indeed, on another blogging occasion where I critically discussed the suggestion that "
autism acceptance could contribute to mental health in autism" (see here) again based on DASS scores, I wonder if a group walking 'intervention' (although I'm not so sure about medicalising such an activity) could also be the topic of more study too, added to other research?

And finally... bearing in mind that exercise might have some nootropic value for some (see here and see this recent study [3]), it seems that much of the chatter about sitting around video game playing fostering "a broad range of cognitive abilities such as visual processing, attention, spatial ability, and cognitive control" is not readily supported by the current peer-reviewed evidence...

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[1] Hallam K. et al. “Happy feet”: evaluating the benefits of a 100-day 10,000 step challenge on mental health and wellbeing. BMC Psychiatry. 2018; 18: 19.

[2] Nah YH. et al. Brief Report: Screening Adults with Autism Spectrum Disorder for Anxiety and Depression. J Autism Dev Disord. 2017 Dec 2.

[3] Gmiąt A. et al. Improvement of cognitive functions in response to a regular Nordic walking training in elderly women - A change dependent on the training experience. Exp Gerontol. 2018 Feb 9. pii: S0531-5565(17)30663-0.

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Wednesday, 14 February 2018

Low grade intestinal inflammation and autism

The suggestion that low grade intestinal inflammation might be related to some autism comes from the findings reported by Katarina Babinská and colleagues [1] (open-access available here).

Researchers set out to "assess the concentrations of fecal calprotectin in a sample of children with ASD [autism spectrum disorder] and to investigate the correlations of this inflammatory marker with the core behavioral symptoms of ASD."

Faecal calprotectin (FC) is a measure of the amount of calprotectin in a stool (poo) sample. It's typically released in response to the presence of inflammation and, here in Blighty at least, is indicated as "an option to support clinicians with the differential diagnosis of inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS) in adults with recent onset lower gastrointestinal symptoms for whom specialist assessment is being considered." 

In terms of research history looking at autism and FC, there is some peer-reviewed science on the topic; also having been included as a parameter in the important paper by Laura de Magistris and colleagues [2] talking about 'leaky gut' in the context of some autism (see here) and how "FC was elevated in 24.4% of patients with autism and in 11.6% of their relatives." Such research is set in the more general context that bowel or gastrointestinal (GI) issues are absolutely no stranger to a diagnosis of autism (see here).

This time around Babinská et al measured FC (via ELISA) in some 87 children diagnosed with an autism spectrum disorder (ASD) aged between 2 and 17 years of age. The authors use the term 'low functioning' to describe this portion of their participant group but I'm rather less enamoured with such labels (see here) despite the well-deserved focus on a group very much under-represented in autism research and other areas. Alongside, over 50 age-matched controls (not-autism) and 29 siblings of children with ASD also provided samples for analysis and comparisons.

Results were not exactly as cut-and-dried as one might have expected. So: "In non-relatives significantly lower values of fecal calprotectin were observed than in both subjects with ASD and their siblings." What this means is that based on group results, those with autism and the siblings of those with autism seemed to manifest higher levels of FC than non-related controls. Based on individual results, where elevated levels of fecal calprotectin was set at 50 µg/g of feces or higher according to test producers guidance as being a level of concern, the frequency of such a finding was greater in those with autism (22%) and their siblings (20%) than in non-related controls (9%) but this difference was reported as 'non-significant'.

Authors also did a little work on another important area in relation to bowel symptoms/pathology and autism: how *might* something like intestinal inflammation 'interact' with the behavioural signs and symptoms of autism? Well, we are told that those diagnosed with autism "had to meet criteria for ASD" on two gold-standard diagnostic tools: the Autism Diagnostic Observation Schedule – second edition and the Autism Diagnostic Interview-Revised (ADI-R). Data from the ADI was examined in the context of the FC findings and lo and behold: "In the group with ASD significant correlations of fecal calprotectin with all domains of the ADI-R diagnostic tool were found: qualitative abnormalities in reciprocal social interaction and communication, restrictive and repetitive patterns of behavior." I say this bearing in mind that similar analyses between FC values and ADOS ratings do not seem to have been either done or reported on for some reason.

When the authors talk about low grade intestinal inflammation as potentially being relevant to some autism, they seem to be accurate insofar as the measured levels of FC in some participants and the *correlation* with autism scores on one of the gold-standard assessment instruments. That being said, there is quite a bit more to do in this area before anyone gets too carried away with the results as they stand. So for example, all that chatter about inflammatory bowel disease (IBD) being related to some autism (see here and see here) did not seem to register in this particular study insofar as the guidance on FC being a marker for possible IBD, albeit based on higher levels of FC being detected: "Active, symptomatic inflammatory bowel disease 200 – 40,000 mg/kg."

I also note that the authors report an important limitation when it came to their research: "Additional factors that might have been a cause of elevated FC levels, such as nutritional or gastrointestinal factors were not analysed." Nutritional factors eh? Y'mean like milk type for example [3] or other dietary and/or environmental factors such as the implementation of a gluten-free diet [4] positively affecting FC levels? Indeed, there are lots of potential factors that could cause a 'false-positive' when it comes to elevated FC such as infections like C. diff or gastrointestinal conditions such as coeliac disease, many of which have shown some important connections to autism (see here for example).

It looks like there is still much more research to do in this area but investigations should definitely continue.

To close, my brood have just discovered the brilliant film 'The Great Escape'. As well as setting up many, many discussions about war, bravery and captivity, they've also commented on the theme tune...

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[1] Babinská K. et al. Fecal calprotectin levels correlate with main domains of the autism diagnostic interview-revised (ADI-R) in a sample of individuals with autism spectrum disorders from Slovakia. Physiol Res. 2017 Dec 30;66(Supplementum 4):S517-S522.

[2] de Magistris L. et al. Alterations of the intestinal barrier in patients with autism spectrum disorders and in their first-degree relatives. J Pediatr Gastroenterol Nutr. 2010 Oct;51(4):418-24.

[3] Ho S. et al. Comparative effects of A1 versus A2 beta-casein on gastrointestinal measures: a blinded randomised cross-over pilot study. Eur J Clin Nutr. 2014 Sep;68(9):994-1000.

[4] Balamtekın N. et al. Fecal calprotectin concentration is increased in children with celiac disease: relation with histopathological findings. Turk J Gastroenterol. 2012;23(5):503-8.

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Tuesday, 13 February 2018

Once more... listen to parents: on the identification of the early behavioural signs of autism

"The results suggest that parents may detect some clinically informative behaviors based on their day-to-day observations more readily than do clinicians during brief clinical assessments."

So said the findings reported by Lori-Ann Sacrey and colleagues [1] who compared the views of parents "of children at high-risk of autism spectrum disorder (ASD; have an older sibling with ASD)" with clinicians opinions when it came to reporting on around 20 clinical signs that could indicate the presence of autism.

Clinicians relied on the Autism Observational Scale for Infants (AOSI) to make their judgements and parents used the Autism Parent Screen for Infants (APSI) (a sort of parent-version of the AOSI) for theirs when infants were between 12 and 18 months of age. Infants being 'observed' subsequently underwent "a blind independent diagnostic assessment for ASD at 36 months of age" to see how accurate those earlier parent and clinician observations were.

The old adage that 'parents generally know their children best' shines through in the Sacrey results with "parent-reported symptoms being better able to differentiate between children with and without ASD at both 12 and 18 months of age compared to clinician observations during a brief office visit." No, most parents aren't experts when it comes to child development and no, typically they aren't seeing lots of children on a day-to-day basis who may present with various developmental issues including autism. But... compared with an often "brief clinical assessment", all those day-in day-out observations that are made - particularly when autism is 'already a part of the family' - do seem to count for quite a bit. Once again, we would all do well to listen to parents (see here) and any concerns they have about their child's development. I might add that combined with the recording technology available to most people these days and the tendency for many parents to document their child's every developmental move, there is potentially plenty of data available for further analysis (see here).

There are a few other issues that could come into play as a result of the Sacrey and other, related but independent findings. I tend to go on quite a bit on this blog about how various 'comorbidities' (if I can still call them that) seem to be over-represented when it comes to a diagnosis of autism. One of the more prevalent ones is that of bowel / gastrointestinal (GI) issues (see here) which is becoming more readily accepted in various circles as being a part of the clinical picture for quite a few people on the autism spectrum. I've talked before about how parents were/are typically the first ones to pick up the bowel-side of things and how, their observations of their own child's bowel symptoms, can on many occasions, provide some important 'pointers' to the professionals (see here). I see the Sacrey work as an extension of this other research, as the message 'listen to parents' continues to be a consistent theme.

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[1] Sacrey LR. et al. Parent and clinician agreement regarding early behavioral signs in 12- and 18-month-old infants at-risk of autism spectrum disorder. Autism Res. 2018 Jan 22.

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Monday, 12 February 2018

Methylphenidate affecting academic performance meta-analysed

When first tweeting about the paper by Anne Fleur Kortekaas-Rijlaarsdam and colleagues [1] I kinda made a mistake. The text of the tweet read something like: "Does methylphenidate improve academic performance? A systematic review and meta-analysis... Pretty much so, but only in relatively small amounts."

Reading that tweet back to myself I realised that by saying 'but only in relatively small amounts' it's highly likely that any readers might have thought that I was talking about the dose of methylphenidate (MPH) rather than the [intended] effect on things like "math productivity (7.8% increase, p < .001); math accuracy (3.0% increase, p = .001); [and] increased reading speed (SMD .47, p < .001)." I apologise, and once again reiterate my blogging (and social media) caveat about not giving anything that looks, sounds or smells like medical or clinical advice.

I did think it worthwhile to write a short post about the Kortekaas-Rijlaarsdam findings given that (a) ADHD (attention-deficit hyperactivity disorder) is something that turns up quite a bit on this blog (see here for example), and (b) pharmacotherapy 'for ADHD' is an important intervention area which has also, unfortunately under some circumstances, been 'hijacked' for other purposes (see here). On that last point, I specifically refer to the idea that for some people, striving for a diagnosis of ADHD is merely a route to either better academic accommodations or perhaps more worryingly, to gain access to a class of medicines with some potentially significant 'cognitive-enhancing' qualities...

What sets the Kortekaas-Rijlaarsdam findings apart from other reviews of the potential nootropic (cognitive enhancing) abilities of something like MPH is their focus on resolving the issue of "whether there are improvements in core academic skills or just improvements in academic productivity" in the context of "the mediating or moderating effects of symptom improvements, demographic-, design- and disorder-related variables."

From a starting number of 148 full-text research articles, the collected texts were screened for eligibility and some 34 were eventually included for meta-analysis ("quantitative synthesis"). These articles were included because they "provided information about either accuracy or productivity scores for math, reading or spelling, or a combination of these" or could at least be calculated on the basis of their included data. Various mediating and moderating variables were also thrown into the statistical mix - "age, gender, percent diagnosed with ADHD-inattentive subtype, and study characteristics: release system, trial duration, and titration method" - and results reported.

As per previous sentences, various aspects of maths performance showed an improvement that correlated with MPH use, and reading speed but not accuracy also came out as potentially showing a relationship with medicine usage. Important too was the information that: "None of our mediators or moderators influenced MPH effects on math and reading accuracy or productivity."

So, following meta-analytic scrutiny of some 1700 children, it looks like there is a small but potentially relevant effect from MPH use of some academic abilities, at least in the short-term ("between 1 and 7 days"). The authors do well not to stray too much into speculating mode when it comes to the cause of any nootropic effect but instead to include the need for more research "to isolate groups of patients who may benefit more or less from MPH and to reveal its mechanism of action." Can't argue with that.

And going back to the topic of cognitive enahncers, an interesting article from a few years back on what they may or may not be doing to elements of our University student body...

Music to close... Sia and Chandelier. Seemingly always playing outside my dojo....

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[1] Kortekaas-Rijlaarsdam AF. et al. Does methylphenidate improve academic performance? A systematic review and meta-analysis. Eur Child Adolesc Psychiatry. 2018 Jan 20.

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Saturday, 10 February 2018

The latest CDC figures on ADHD medication trends among women aged 15-44

The report published by Kayla Anderson and colleagues [1] has made quite a few media headlines (see here for example) based on their observations that: "The percentage of privately insured reproductive-aged women who filled a prescription for an ADHD [attention-deficit hyperactivity disordermedication increased 344% from 2003 (0.9%) to 2015 (4.0%). Further: "ADHD medication prescriptions increased across all age groups and U.S. geographic regions, and the increase was confined to stimulant medications."

"The new report raises questions about the increasing use of a diagnosis that once was reserved for children and adolescents" was one of the issues discussed following the publication of the Anderson report. This continues a theme in psychiatric circles on whether the diagnosis of ADHD is being 'over-used' across many different age groups [2]. Another issue - that of the potential performance-enhancing abilities of certain medicines commonly indicated for managing ADHD (see here for a recent review [3]) - has also come into the media spotlight too as a result of these latest findings.

A further point of discussion has also been noted by Anderson et al: "ADHD medication prescriptions are increasingly common among privately insured, reproductive-aged women. Additional research on ADHD medication safety among this population, including safety before and during pregnancy, could help women and their health care providers make evidence-based decisions concerning the risks and benefits of pharmacologic and behavioral treatment options for common conditions, including ADHD." The question raised is whether use of something like "a prescription for mixed amphetamine salts... for lisdexamfetamine.. for methylphenidate" is 'safe' before and during pregnancy when it comes to offspring health, wellbeing and development?

The area of pregnancy medicine use is a particularly complicated issue. Not least because various medicines used before and during pregnancy have come under the spotlight in recent times, in terms of their potential effects on the unborn child. Ranging from the pretty convincing valproate story (and guidance) (see here) to the *possible* effects of various anti-depressants (see here) to that of over-the-counter pain relief medicines (see here), the research literature is quite 'lively' when it comes to pregnancy pharmacotherapy. Of course there are gaps in the literature as it stands, and one should never forget that many of the prescription medicines under the research spotlight are not typically prescribed and dispensed willy-nilly, but...

In relation to 'stimulant medication' indicated for ADHD and any effect(s) on the unborn child, we're not yet in any position to make any valued judgements just yet. There is some research out there [4] and it's not all positive [5] but a lot more investigations are indicated. I say that bearing in mind that: (a) ADHD might not be the only condition/label given to some mothers, which will likely affect their medication profile too (see here for example), and (b) much like other work looking at medicines and risk of 'adverse' childhood issues, there's always the possibility that the risk to offspring *might* be elevated as a result of the underlying condition being treated/managed (i.e. ADHD) or some related comorbidity irrespective of any medication influences.

I'm not coming out as any sort of 'champion' for ADHD medications (despite their quite impressive safety and efficacy profiles) but neither am I going to demonise a whole class of medicines based on a currently pretty scant evidence base. Understanding also how much of an effect a diagnosis of ADHD can have on a person (see here and see here for examples), further investigations are indicated before hype and sweeping generalisations take hold.

And this is not the first time that research has indicated that ADHD medication use is on the up (see here)...

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[1] Anderson KN. et al. Attention-Deficit/Hyperactivity Disorder Medication Prescription Claims Among Privately Insured Women Aged 15-44 Years - United States, 2003-2015. MMWR Morb Mortal Wkly Rep. 2018 Jan 19;67(2):66-7

[2] Danielson ML. et al. Prevalence of Parent-Reported ADHD Diagnosis and Associated Treatment Among U.S. Children and Adolescents, 2016. J Clin Child Adolesc Psychol. 2018 Jan 24:1-14.

[3] Kortekaas-Rijlaarsdam AF. et al. Does methylphenidate improve academic performance? A systematic review and meta-analysis. Eur Child Adolesc Psychiatry. 2018 Jan 20.

[4] Nörby U. et al. Perinatal Outcomes After Treatment With ADHD Medication During Pregnancy. Pediatrics. 2017 Dec;140(6). pii: e20170747.

[5] Bro SP. et al. Adverse pregnancy outcomes after exposure to methylphenidate or atomoxetine during pregnancy. Clin Epidemiol. 2015 Jan 29;7:139-47.

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Friday, 9 February 2018

"ASD characteristics in adulthood are differently perceived across age, sex, and informants"

The research tag-team that is Anne Lever and Hilde Geurts have provided peer-reviewed fodder for this blog before (see here and see here). Without wishing to cajole their research interests into a specific box, quite a bit of their time seems to be taken up by looking at autism in the context of ageing, alongside how the label of autism does not seem to have a monopoly on the presentation of certain autistic traits.

A recent paper published by this team [1] provides yet more blogging material, specifically focused on testing "the association between age and ASD [autism spectrum disorder] characteristics, including empathy and sensory sensitivity, in adults aged 19–79 years." A scientific hat-tip is offered to other research in this area [2] that previously observed that: "older age was associated with higher ratings of ASD traits and better cognitive performance."

Drawing on data derived from a participant group numbering above 400 (N=237 with autism and N=198 without autism) spanning the age ranges, a variety of self-report and informant-report (family members, friends, other significant others) were utilised. I should point out that the autism participant group seemed to be represented by the 'more able' part of the autism spectrum (I don't use the term 'functioning') insofar as most either being diagnosed with Asperger syndrome or PDD-NOS (pervasive developmental disorder - not otherwise specified), being predominantly independent or living with a partner or housemate in residential status terms and also with that reliance on self-report used throughout the study kept in mind. This is worth knowing given other discussions on under-represented groups when it comes to scientific study (see here) and how representative autism research may or may not be to the entire spectrum.

Among the measures included for analysis we have an old favourite - the Autism-Spectrum Quotient (AQ) - as well as the Interpersonal Reactivity Index (IRI) (measuring various aspects of empathy) and the Sensory Sensitivity Questionnaire (SSQ) (examining sensory hyper- or hyposensitivity). Obtained results were collated and subjected to quite a few statistical analyses.

Results: noted as a 'group difference' findings were reported observing that: "Adults with ASD reported higher scores on the SSQ and on all subscales of the AQ than adults without ASD." This is pretty much what would be expected, despite any qualms I might have about what the AQ actually measures (see here for more of them). Sensory issues being reported as being greater in those with a diagnosis of autism also ties in well with their inclusion in the DSM-5 schedule for diagnosing autism or ASD (see here).

Then: "Within the ASD group, age-related differences were observed in self-reported ASD traits and sensory sensitivity, with a peak among middle-aged adults." Alongside that previously 'hat-tipped' study, the authors conclude that "ASD characteristics are more heavily experienced in middle adulthood than in younger or older adults." This is interesting from quite a few perspectives; bearing in mind that such findings say nothing about the expression of autism in childhood and early adulthood. Appreciating that the self-report of autism or sensory traits may not be the same as everyday autism expression, such findings *might* have some relevance to various issues such as the rise and rise of adult autism diagnoses being given and indeed, how a diagnosis of autism for some (a few?) might not be a 'lifelong' issue (see here). I know that last point raises blood pressure in some quarters as words like 'masking' are banded around (with the need for far greater study), but there is good reason to think that like many other conditions/labels, autistic behaviours and/or traits ebb and flow according to environment and perhaps other factors, such as the presentation of comorbidity for example (as per the author's other work [3] already mentioned). In short, the presentation of autism is probably dynamic and fluidic, rather than just a static thing.

Onward: "we replicated earlier findings that females with ASD had more sensory issues and reported more ASD characteristics than males... whereas females without ASD manifested fewer ASD traits than non-ASD males.". Females with ASD (74 females vs. 163 males) 'reported more ASD characteristics than males'? Intriguing - "ASD females reported higher scores than ASD males on the AQ total score" - to say the least in light of other [childhood] findings [4] but not without cautions. I go back once again the question of what the AQ is actually measuring and whether for example, the typically higher rate of mood disorders generally noted in females could be a potential confounder when it comes to AQ scores in the context of that previous reference [3] from the authors. This area requires further investigation.

Finally: "Overall, the current results show poor to fair agreement between self- and other-reports of well-known proxies, even though the agreement of the overall group was similar to those previously reported for social responsiveness." Again, some potentially important lessons to be learned here insofar as the 'meaning of autism' to a person and those around them. Indeed I note the authors' offer one explanation: "the self may be more accurate about traits that describe unobservable thoughts and feelings due to privileged access (e.g. feelings of empathy and sensory sensitivity), whereas an informant would be more accurate about observable behavior (e.g., ASD traits)." Again, jumping back into 'hot potato' territory, such a finding may have implications for the whole 'self-diagnosed vs. formal diagnosis' debate that still continues at a pace (see here).

There is quite a bit more to take in from this latest paper from Lever & Geurts and definitely some food for thought. I'll leave you however with one final quote from the authors that is perhaps one of the more important take-away points from their study: "it is important to repeatedly assess self-reported ASD characteristics during adulthood." Who would argue with that in terms of getting wants, wishes, needs and requirements accurate and up-to-date?

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[1] Lever AG. & Geurts HM. Is Older Age Associated with Higher Self- and Other-Rated ASD Characteristics? Journal of Autism & Developmental Disorders. 2018. Jan 18.

[2] Happé FG. et al. Demographic and Cognitive Profile of Individuals Seeking a Diagnosis of Autism Spectrum Disorder in Adulthood. J Autism Dev Disord. 2016 Nov;46(11):3469-3480.

[3] Geurts HM. et al. Autism Characteristics in Older Adults with Depressive Disorders. The American Journal of Geriatric Psychiatry. 2016; 24: 164-169.

[4] Øien RA. et al. Sex-Differences in Children Referred for Assessment: An Exploratory Analysis of the Autism Mental Status Exam (AMSE). J Autism Dev Disord. 2018. Feb 8.

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Thursday, 8 February 2018

Maternal diabetes and offspring autism risk meta-analysed

"Maternal diabetes, especially gestational diabetes mellitus, is associated with ASDs [autism spectrum disorders] in offspring based on a limited number of convincing case-control studies. More large-scale population-based prospective studies are still needed to draw firm conclusions."

So concluded the systematic review and meta-analysis by Hongquan Wan and colleagues [1] taking on an important question: does maternal diabetes confer an enhanced risk of offspring autism? Diabetes by the way, covers quite a bit of diagnostic ground, but is typically characterised by elevations in blood sugar levels and the various ways that this can (and does) affect biology and risk of some important adverse conditions.

Yes, appears to the answer based on the peer-reviewed research literature so far (until June 2017) with regards to maternal diabetes affecting offspring autism risk; although with it, a greater need to confirm such findings and also elucidate possible genetic and biological pathways linking diabetes exposure and offspring autism risk is required. I might add that having covered this topic a few times on this blog (see here and see here), including discussing other meta-analysis results [2], I'm not all that surprised by the findings.

Wan et al report results based on 12 articles - "7 were case-control studies... and 5 were cohort study." Combining results in a meta-analytic fashion produced some important observations: "The overall analysis demonstrated that gestational diabetes increased the risk of ASD by 48%" and when reliant on "case-control studies with moderate... or high quality [standing]", the risk increased to over 60%. In short, maternal diabetes exposure does seem to have something of an important effect on offspring risk of autism.

Mechanism(s) of effect? Well, the authors do provide some summary of hypotheses previously put forward. Diabetes exposure causing "brain malformation and aberrant neurodevelopment" is one theory; with words such as "enhanced cell apoptosis and activated oxidative stress" also included. Even possible immune system effects gets some airtime; as the discussion also turns to "the presence of autoantibodies" as a potentially important variable. Autoantibodies, I might add, are part and parcel of at least one type of diabetes. I might also throw in the idea of foetal programming as an over-arching concept to perhaps keep in mind and with it, the implication that early and timely diagnosis and management of maternal diabetes both before and during pregnancy *could* potentially affect offspring autism risk. *Could* is the operative word there...

But... alongside all the 'we need more and better research in this area' sentiments, I'm also minded to highlight how maternal diabetes - in all it's forms - is not necessarily a stand-alone condition. Indeed, it's an important point to remember that when talking about pregnancy factors in the context of something like offspring autism risk, there could be a range of separate but overlapping issues to contend with (see here and see here for examples) which complicate any attempts to single out particular variables as being more or less important when it comes to offspring outcomes.

It's also unwise to assume that 'all autism' is somehow conception or pregnancy-associated either (see here and see here)...

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[1] Wan H. et al. Association of maternal diabetes with autism spectrum disorders in offspring: A systemic review and meta-analysis. Medicine. 2018' 77: e9438.

[2] Xu G. et al. Maternal diabetes and the risk of autism spectrum disorders in the offspring: a systematic review and meta-analysis. J Autism Dev Disord. 2014 Apr;44(4):766-75.

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