Cardiometabolic healthy and unhealthy obesity: does vitamin D play a role?

The aim of this observational study was to clarify the link between vitamin D status and metabolic syndrome (MetS) in people with visceral obesity. Design and methods One-hundred-ninety-six consecutive patients (152 women; mean age 51±13 years) with visceral obesity [mean body weight 103±20 Kg, mean waist circumference (WC) 119±13 cm] were enrolled at the Obesity Outpatient Clinic of the University of Insubria in Varese. Anthropometric measurements were recorded. Laboratory tests, including vitamin D [25(OH)D)], fasting blood glucose (FBG), lipid profile, liver and kidney function tests were assessed. Vitamin D status was defined according to the European Society of Endocrinology guidelines, MetS to the 2009 harmonized definition. An inverse association emerged among [25(OH)D], body mass index (BMI) (p=0.001) and WC (all p=0.003). Serum [25(OH)D] levels were inversely related to FBG and systolic blood pressure (SBP) (respectively, p=0.01 and 0.02). Median serum [25(OH)D] levels were 13.3 ng/ml (CI 95% 12;15) in MetS and 16 ng/ml (CI 95% 14;18) (p=0.01) in non-MetS patients. Among patients with MetS, lower [25(OH)D] concentrations were related to higher risk of hypertension (HT) [Odds Ratio (OR) 1.7, CI 95%, 0.7;4] and hyperglycemia (IFG)/ type 2 diabetes (OR 5.5, CI 95% 2;14). Vitamin D status and MetS are inversely correlated in visceral obesity, particularly with regard to glucose homeostasis and BP. More extensive studies are required to investigate the potential for causality.