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Prevalence of vitamin D deficiency and insufficiency is improving, but is still high in Iranian adults

Posted on: December 27, 2017   by  Vitamin D Council


A recent study published in the Journal of Nutritional Science and Vitaminology determined that while prevalence of vitamin D insufficiency and deficiency is decreasing in Iran, many adults are still not attaining vitamin D sufficient status.

Researchers conducted a longitudinal study from 2001 to 2013 in 370 Iranian adults to determine the prevalence of vitamin D insufficiency and deficiency. Individuals were excluded from the study if they had a history of chronic illness.

The participants completed self-administered health questionnaires, received anthropometric measurements and had their vitamin D levels tested at baseline in 2001, 2007 and at conclusion of the study in 2013. Vitamin D deficiency was defined as having levels less than 12 ng/ml (25 nmol/l), insufficiency as having levels between 12-20 ng/ml (25-50 nmol/l) and sufficiency as having levels greater than 20 ng/ml (50 nmol/l).

This is what the researchers found:

  • Average vitamin D levels were 20.8 ng/ml (52.1 nmol/l), 21.7 ng/ml (54.3 nmol/l) and 24.5 ng/ml (62.3 nmol/l) in 2001, 2007 and 2013, respectively.
  • Vitamin D status was not significantly impacted by socio-demographic factors, age, gender or BMI.
  • When adjusted for confounding factors, there was a decrease in vitamin D deficiency and an increase in vitamin D sufficiency over the 12 year period (p = 0.001).
  • Despite the improvement in vitamin D status, vitamin D insufficiency and deficiency was 62.0%, 57.9% and 53.9% in 2001, 2007 and 2013.

The researchers concluded:

“In conclusion, the present study revealed that there was significant improvement in vitamin D status among Iranian adults over the 12-y period. However, the current prevalence of this nutrient deficiency is still high enough to be considered a significant public health issue.”


Khosravi-Boroujeni, H. Et al. Prevalence and Trends of  Vitamin D Deficiency among Iranian Adults: A Longitudinal Study from 2001–2013. Journal of Nutritional Science and Vitaminology, 2017.

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