Serum levels of 25-hydroxyvitamin D in mothers of Swedish and of Somali origin who have children with and without autism

FAB RESEARCH COMMENT:

Vitamin D is best known for its key role in calcium absoprtion and bone health, but adequate supplies during pregnancy and early life are also essential for normal brain development and function.

Animal studies have repeatedly shown that maternal Vitamin D deficiency during pregnancy can permanently disrupt brain development and function in the offspring - leading to lifelong behavioural disturbances resembling ADHD, autism, schizophrenia and related developmental or mental health conditions.

This evidence has raised the important question of whether Vitamin D deficiency during pregnancy may lead to similar effects on brain development and behaviour in humans. 

Individuals with darker skin have a higher risk of Vitamin D deficiency than those with paler skin, other things being equal (as melanin reduces the amount of Vitamin D that can be made by exposure of skin to bright sunlight).  It is therefore plausible that Vitamin D deficiencies might contribute to at least some of the elevated risks for developmental and mental health conditions observed in darker-skinned migrant populations in countries where pale skin has hitherto been the norm (as low melanin is now thought to be an evolutionary adaptation to a relative lack of sunlight).

In the current study, Somali-born mothers in Sweden were found to have significantly lower Vitamin D status than matched controls with Swedish ancestry. And Vitamin D status was lowest in those Somali mothers whose child had been diagnosed with autism.

While the Vitamin D status of this group was not significantly lower than that of Somali mothers with typically developing children (and this would require very large differences given the small study numbers), the difference was in the predicted direction - suggesting that further investigations are merited.  

See also:

• Barnevik-Olsson et al 2010 - Prevalence of autism in children of Somali origin living in Stockholm: brief report of an at-risk population

See also:

• Scientific American - What If Vitamin D Deficiency is a Cause of Autism?

• Grant & Soles 2009 - Epidemiologic evidence supporting the role of maternal vitamin D deficiency as a risk factor for the development of infantile autism

• Cannell 2008 - Autism and vitamin D

And for more information on Vitamin D and autism, please see the following lists, which are regularly updated:

• Vitamin D and Autism - News

• Vitamin D and Autism - Research