Severe hypovitaminosis D is widespread and more common in non-diabetics than diabetics in Saudi adults.

Objective: To compare the incidence of hypovitaminosis D in subjects, with and without type 2 diabetes mellitus (T2DM), and determine its association to various risk factors.

Methods: Three hundred and forty-one (177 non-diabetic, and 164 T2DM) Saudi adults were included in this cross-sectional study conducted at the Biomarkers Research Program (BRP) of King Saud University, Riyadh, Kingdom of Saudi Arabia from March to August 2009. Anthropometrics and fasting blood samples were obtained. Fasting glucose (FG) and lipid profiles were determined. Serum 25-hydroxy vitamin D (25[OH]D) and parathyroid hormone (PTH) were quantified using enzyme-linked immunosorbent assay. Severe hypovitaminosis D was defined as serum 25(OH)D with levels <12.5 nmol/l.

Results: Age was the most significant predictor of 25(OH)D in both groups, explaining 25% (p=0.0005) and 16% of variances (p=0.0005). Waist-hip ratio, systolic blood pressure and body mass index were significant predictors of 25(OH)D among non-diabetics after age adjustment, explaining 21% of variance perceived (p=0.039). Serum PTH levels were higher in non-diabetic men and women.

Conclusion: Severe hypovitaminosis D is prevalent in both non-diabetic and diabetic Saudis, but was more common in the young and middle-aged non-diabetics. The study further underscores the need for vitamin D fortification of the Saudi diet, and the promotion of vitamin D supplementation in both groups.