Normal values of Vitamin D and prevalence of Vitamin D deficiency among Iranian population

Vitamin D requirements are met by its synthesis in the skin as a result of exposure to UVB (ultra violet B) and also by food. Despite abundant UVB in sunny countries, there is evidence of high prevalence of Vitamin D (vit D) deficiency in these areas.

5 cities with different longitudes and latitudes were chosen. Patients were selected by random cluster sampling. Blood samples obtained from healthy subjects. After centrifuging the sera collected sent to the EMRC (Endocrinology & Metabolism Research Centre) laboratory for measurment of 25(OH) vitamin D [25(OH)D] and PTH levels. Based on the level of 25(OH), the subjects were classified into 7 groups. Different levels of Vit D deficiency were determined as normal, mild, moderate and severe Vit D deficiency.

5329 people were evaluated for 25(OH)D and three threshold levels for women (40, 25 and 12 nmol/L) and two for men (35 and 25 nmol/L) were determined. Mild Vit D deficiency was observed in 27.2% of women and 37.25% of men. Severe or moderate Vit D deficiency was noticed in 47.85% of women and 34.75 % of men.

The results of this study are compatible with those of other studies in the Middle East. Prevalence of Vit D deficiency in these areas needs justification. Plans for fortification of articles of food with Vit D are recommended.