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Vitamin D deficiency is more common in those with intellectual disabilities compared to the general population

Posted on: September 30, 2014   by  Vitamin D Council


A new study from The British Journal of Psychiatry has found that vitamin D deficiency is very common in those with intellectual disabilities and may be due to unique, undetermined risk factors.

A person is considered to have an intellectual disability if, before the age of 18, they show a lack of intellectual functioning and a limited ability to adapt new social and daily living skills.

People with intellectual disabilities are often institutionalized and bound to a carer who monitors their everyday activity. This, along with other factors, can limit the patient’s ability to go outside and get sun exposure, which is why researchers believe vitamin D deficiency is of great concern in this population.

Indeed, research on vitamin D deficiency in those with intellectual disabilities has found that, among institutionalized patients, deficiency is extremely prevalent, with some estimates as high as 100%.

Research on vitamin D in community-dwelling patients, individuals with intellectual disabilities who live in small care facilities or in their own home with a carer present, is very limited.

A research team recently conducted a study in which they compared the vitamin D levels of 155 participants with intellectual disabilities to 192 healthy participants.

Those with vitamin D levels lower than 20 ng/ml were given 50,000 IU of vitamin D daily for 3-6 days followed up by 50,000 IU of vitamin D monthly as a maintenance dose. This dose was compared to patients taking 400 IU and 800 IU supplements given by their general practitioners.

The researchers found that 77.3% of those with intellectual disabilities had levels lower than 20 ng/ml compared to 39.6% of the healthy participants.

Winter season, obesity and impaired mobility were independently related to lower vitamin D levels, however this only explained 32% of the deficiencies observed, suggesting there are other risk factors not yet determined in this patient population.

Finally, the 50,000 IU supplementation regimen was safe and effective in raising 100% of the patients’ levels to levels above 20 ng/ml. This was compared to 80% of the patients who were taking 800 IU/day.

“The results of our study show that vitamin D deficiency is highly prevalent in community-living patients with intellectual disabilities, and that it can be effectively, safely and inexpensively treated,” the researchers concluded.


Frighi, V. et al. Vitamin D deficiency in patients with intellectual disabilities: prevalence, risk factors and management strategies. The British Journal of Psychiatry, 2014.

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