Tuesday, 19 July 2011

Even Superman had problems with lead

Whilst the Man of Steel was all but impervious to bullets and explosions, he was not without his weaknesses. Kryptonite was his primary problem, but when it came to using that X-ray vision of his, another obstacle stood in his way, lead.

Lead (Pb or plumbum) has popped up here and there in a few recent posts on this blog. It was one of the factors, the reduction of which, was put forward to partially account for the drop in crime levels in the US in this post; a factor no-one can rule out in relation to the risk of being diagnosed with ADHD in this post; and also exemplified as the archetypal behaviour-changer in this post on detox. Yes sir, lead might have quite a bit to answer for.

Lead exposure is a well-known effector of health. For children with their developing brain in particular, lead exposure is not good news and can affect both physical and cognitive development. It is perhaps with these quite important effects in mind, that lead exposure has been looked at with reference to quite a few childhood conditions, including those with a developmental aspect to them such as ADHD.

The possibility that lead exposure either pre-, peri- or post-natally might be implicated in the risk of being diagnosed with an autism spectrum condition has also been the topic of some research. Studies such as this one, this one and this one have all suggested some (varying) association between lead exposure and autism, either on the basis of treatment figures or based on biological measures of detected amounts. The literature has been joined by this recent paper suggesting chronic lead toxicity in a number of children with autism resident in Saudi Arabia.

I have blogged about the Saudi research group involved in this new study already, based on their excellent publication record this year in autism research which rivals that of the MIND Institute and Prof. Jim Adams. In this latest trial, for which I only have the abstract so far, it appears that they are signalling post-natal lead toxicity as, quote ".. could represent a causative factor in the pathogenesis of autism" on the basis of some very high levels of the lead ion being detected in plasma. Don't ask me how they made the detection because I don't have the full-text paper yet, but I would hazard a guess that based on their results they might have used our old friend ICP Mass Spectrometry or possibly via atomic absorption.

I don't want to go too overboard on this latest study yet. It is interesting to note that lead poisoning in the early years can affect various brain functions including synaptogenesis and the correct functioning of the blood-brain barrier. Both of which have been implicated, to varying degrees in cases of autism and related developmental conditions. Having said that, autism does not seem to have a monopoly on these issues outside of other conditions; whether such mechanisms could so fundamentally affect a person as to 'lead' (pardon the wordplay) to autism or autistic symptoms I don't know.

There are various potential implications from any association between lead and autism. Risk issues such as the environment, the prevalence of pica in autism and the various suggestions about the use of chelating agents to remove bioaccumulated lead all might figure in any discussions. What I would perhaps like to see initially is some guidance on ruling out lead poisoning in any and all cases of developmental diagnoses as a routine measure, bearing in mind what is known about the effects of lead and the developing brain.