Low serum 25 hydroxyvitamin D3 (vitamin D3) is known to perturb cellular function in many tissues, including the endocrine pancreas, which are involved in obesity and type II diabetes mellitus (TIIDM). Vitamin D3 insufficiency has been linked to obesity, whether obesity is assessed by body mass index (BMI) or waist circumference (waist). Central obesity, using waist as the surrogate, is associated with the metabolic syndrome (MetSyn), insulin resistance, TIIDM and atherosclerotic cardiovascular disease (CVD).
McGill, A., Stewart, J., LITHANDER, F., Strik, C., & Poppitt, S. (2008). Relationships of low serum vitamin D3 with anthropometry and markers of the metabolic syndrome and diabetes in overweight and obesity. Nutrition Journal, 7(1), 1-1. https://doi.org/10.1186/1475-2891-7-4