Autism linked to vitamin D deficiency during pregnancy, researchers find

[nitpicker]

https://www.theguardian.com/society/2016/dec/14/autism-linked-to-vitamin-d-deficiency-during-pregnancy-researchers-find

Autism linked to vitamin D deficiency during pregnancy, researchers find

Study finds pregnant women with low vitamin D levels at 20 weeks more likely to have a child with autistic traits

A study linking autism with vitamin D deficiency has sparked calls for the widespread use of supplements during pregnancy, with researchers not recommending more sun exposure due to increased risk of skin cancer.

Wednesday 14 December 2016 03.21 GMT

The important role vitamin D plays in early life is back in the spotlight after Australian researchers noticed a link between a deficiency during pregnancy and autism. The study found pregnant women with low vitamin D levels at 20 weeks’ gestation were more likely to have a child with autistic traits by the age of six. The finding has led to calls for the widespread use of vitamin D supplements during pregnancy, just as taking folate has reduced the incidence of spina bifida in the community.
(snip)

The study examined approximately 4,200 blood samples from pregnant women and their children, who were closely monitored as part of the long-term “Generation R” study in Rotterdam, the Netherlands. Blood samples with a vitamin D reading of less than 25.0 nmols is considered deficient.
(snip)

Earlier this year, an Australian study, published in the Journal of Allergy and Clinical Immunology, showed vitamin D wasn’t just important during pregnancy but also in the first decade of a child’s life. Researchers at the Murdoch Children’s Institute found evidence of a clear link between a lack of vitamin D in early childhood and allergic disorders such as asthma and eczema.

[Buckeye_Democrat]

1. If this is true, then I'd expect darker-skinned mothers to show...

... a higher rate of children with autism spectrum disorder and the associated impairments in learning and socialization.

Is there any evidence for that?

Darker skin makes it harder to convert sunlight to Vitamin D, which is the consensus explanation for skin turning lighter (over generations) as humans migrated out of Africa into less sunny and colder (more clothing) regions.

It should also be higher among mothers with poor diets since Vitamin D also comes from food, of course.

[HockeyMom]

2. Why far more boys than than girls?

I worked with children on the autism spectrum for many, many years in schools. The vast majority were boys. One family had 6 children. All 3 boys were autistic but none of their 3 daughters were. In other families with 2 children, it was always the son, but not the daughter.

Perhaps it is carried on the Y chromosome? BTW, I worked in South Florida; the Sunshine State. I cannot say that it affected Black children more than White children. Gender was more relevant.

[Buckeye_Democrat]

3. Note sure. A link between Vitamin D and estrogen levels in the womb?

[Buckeye_Democrat]

4. Here's an interesting paper.

http://www.direct-ms.org/sites/default/files/Cannell%20Autism%20Vit%20D.pdf

Vitamin D and skin color
Vitamin D deficiency discriminates based on the
amount of cutaneous melanin, a proficient and
ever-present sunscreen. The vitamin D theory pre-
dicts that neurodevelopmental disorders would be
more common in children born to darker-skinned
mothers. Such studies are difficult as they raise
sensitive social issues although three of four recent
US studies found a higher incidence of autism in
black children, sometimes appreciably higher.

Furthermore, in Europe, autism rates
are higher in children of dark-skinned immigrants.

Gillberg et al. reported that the incidence
of autism in Goteborg, Sweden, for children born
to the very dark-skinned women who emigrate
from Uganda, was 15%, about 200 times higher than
the general population.

Sexual differences and vitamin D
Estrogen and testosterone appear to have strikingly
different effects on vitamin D metabolism, which
may explain the striking sex differences in autism.
For example, Epstein and Schneider report, ‘‘the
majority of studies have found a positive effect
of estrogen on calcitriol levels’’, but after
reviewing studies on testosterone, they found no
similar effects (p. 1261). If estrogen increases neu-
ral calcitriol, but testosterone does not; such dif-
ferences during brain development may mean
that estrogen shields developing female brains
from calcitriol deficiencies, while testosterone ex-
poses male ones.

[Nitram]

5. Thanks, Buckeye. Interseting post.

[Warpy]

6. Since it is expressed differently in girls, they're falling through the diagnosis cracks

https://www.scientificamerican.com/article/autism-it-s-different-in-girls/

We know it's present at birth. I've often wondered if it began in utero. The Vitamin D theory works as well as a lot of others, at this point, but likely it's a complex enough disorder that they'll find a whole host of causes.

It's just not the vaccines. Sorry, Wakefield, you corrupt sack of shit.