Vitamin D3 Levels Tied to Diabetes Mortality

GENTOFTE, Denmark

Severe vitamin D deficiency in people with type II diabetes has been linked to all-cause mortality but not microvascular complications in the eyes and kidneys, according to Danish researchers. They published their findings in a recent issue of Diabetes Care journal (24(5):1081-85)

In their prospective observational follow-up study, researchers followed an inception cohort of type 1 diabetic patients from onset of diabetes diagnosed between 1979 and 1984. Plasma vitamin D [25(OH)D3] levels were determined by high performance liquid chromatography(HPLC)/tandem mass spectrometry in 227 patients before the patients developed microalbuminuria. They considered values equal to or below the 10-percentile (15.5 nmol/L) as severe vitamin D deficiency.

Median (range) vitamin D was 44.6 (1.7–161.7) nmol/L. Vitamin D level was not associated with age, sex, urinary albumin excretion rate (UAER), or blood pressure. During follow-up, 44 patients (18 percent) died. Using a Cox proportional hazards model, researchers discovered the hazard ratio for mortality in subjects with severe vitamin D deficiency was 2.7 (1.1–6.7), P = 0.03, after adjustment for UAER, HbA1c (glycated hemoglobin) and conventional cardiovascular risk factors (age, sex, blood pressure, cholesterol, smoking).

Overall, 81 (37 percent) of the 220 patients developed microalbuminuria, and 27 (12 percent) of these progressed to macroalbuminuria. Further, 192 patients (87 percent) developed background retinopathy, while only 34 (15 percent) progressed to proliferative retinopathy. In the end, severe vitamin D deficiency at baseline did not predict the development of these microvascular complications.