Thursday, 2 June 2011

Coeliac disease and cataracts?

Given that one of the more consistent interests on this blog is related to the gut and the various gastrointestinal (GI) co-morbidities that have been noted alongside some cases of autism spectrum and related conditions, it is little surprise that I have arrived at yet another potential manifestation of one such co-morbidity, coeliac disease (CD); this time looking at its possible relationship with cataracts.

The US National Institutes of Health (NIH) carry some good information on cataracts: what they are and how they come about. A cataract is defined as a clouding of the lens of the eye which affects vision and is primarily a condition associated with age although there are other factors also involved depending on the type of cataract. It was interesting to read that the various 'risk' co-morbidities attached to cataracts include both disease and environment. Cataracts are one of the primary causes of blindness around the globe and a condition which really should not be as prevalent as it is given its high degree of 'treatability' through fairly routine surgery.

An interesting study has appeared suggesting that a diagnosis of CD may increase the risk of developing cataracts. This follows on from a previous case report potentially linking cataract with CD (said subject of this case only being 18 years old) and a suspicion of a link in cases of CD co-presenting with hypoparathyroidism. The current study assessed data on over 28,000 people diagnosed with CD over a 40-year period and using some nifty statistics compared each of them with 5 non-CD controls to assess the risk of cataracts in CD (I think you can see that the sample base was huge). The results suggested that approximately 4% of patients with CD developed cataracts over the course of the follow-up period (where roughly 3% would be expected). I know what you are saying 4% over 3%, so what? Well percentages perhaps don't give the true story here given that an excess of 250 people with CD developed cataracts over the examination period, which in statistical terms represents an increased risk.

Despite being a comparatively small risk, extra-intestinal symptoms like cataracts potentially related to CD are always of some interest to me and quite a few others because they provide a tantalising peek into how CD might manifest itself outside of the common GI symptoms. In the cases of CD and cataracts described here, one of the main theories linking the two is hypocalcaemia as a result of the malabsorptive effects of CD which has been previously discussed in the research literature. Once again those pesky malabsorption (and gut permeability?) issues seem to end up disrupting all manner of systems and not just in the short term. On a similar note I would perhaps refer you to an interesting post over at Brain Posts by Bill Yates on the role of fibre (UK spelling) and inflammation and how CD might represent yet another risk factor.

As far as I am aware, cataracts in relation to autism run at about the same prevalence rate (?) as they do in the general population. There is the odd paper suggesting a possible link between the features of autism, cataracts and various genetic disorders but very little else. There is also perhaps some tie-up between some of the various risk factor conditions for cataracts and autism; not least congenital rubella and diabetes but I don't want to stretch any relationship, that at the moment does not appear to be present. Whether the risk of cataracts will become more relevant to autism as the autistic population age, I dunno.