Association of vitamin D2 and D3 with type 2 diabetes complications

Aims Vitamin D measurement is a composite of vitamin D-2 (25(OH)D-2) and D-3 (25(OH)D-3) levels, and its deficiency is associated with the development of type 2 diabetes (T2DM) and diabetic complications; vitamin D deficiency may be treated with vitamin D-2 supplements. This study was undertaken to determine if vitamin D-2 and D-3 levels differed between those with and without T2DM in this Middle Eastern population, and the relationship between diabetic microvascular complications and vitamin D-2 and vitamin D-3 levels in subjects with T2DM(.) Methods Four hundred ninety-six Qatari subjects, 274 with and 222 without T2DM participated in the study. Plasma levels of total vitamin D-2 and D-3 were measured by LC-MS/MS analysis. Results All subjects were taking vitamin D-2 and none were taking D-3 supplements. Vitamin D-2 levels were higher in diabetics, particularly in females, and higher levels were associated with hypertension and dyslipidemia in the diabetic subjects (p < 0.001), but were not related to diabetic retinopathy or nephropathy. Vitamin D-3 levels measured in the same subjects were lower in diabetics, particularly in females (p < 0.001), were unrelated to dyslipidemia or hypertension, but were associated with retinopathy (p < 0.014). Neither vitamin D-2 nor vitamin D-3 were associated with neuropathy. For those subjects with hypertension, dyslipidemia, retinopathy or neuropathy, comparison of highest with lowest tertiles for vitamin D-2 and vitamin D-3 showed no difference. Conclusions In this Qatari cohort, vitamin D-2 was associated with hypertension and dyslipidemia, whilst vitamin D-3 levels were associated with diabetic retinopathy. Vitamin D-2 levels were higher, whilst vitamin D-3 were lower in diabetics and females, likely due to ingestion of vitamin D-2 supplements.