Association between Vitamin D and Metabolic Indexes in Patients with Polycystic Ovary Syndrome

Objective: The aim of this study was to investigate the effect of vitamin D on the metabolic characteristics of polycystic ovary syndrome(PCOS) and its mechanism.

Methods and Results: 155 cases of PCOS patients and 74 non-PCOS women withmatched age and BMI were enrolled in this study.Data were collected from May 2016 to November 2017. Plasma 25-hydroxyvitamin D[25(OH)D], metabolic markers, and sex hormones were measured. Homeostasis model assessment(HOMA-IR), triglyceride(TG), testosterone(T), free androgen index(FAI) and uric acid(UA) were significantly increased(P<0.05) while 25-(OH)D, high-density lipoprotein cholesterol (HDL-C) and sex hormone binding globulin(SHBG) were lower(P<0.05) in PCOS than non-PCOS. Body mass index(BMI), fasting plasma insulin(FINS), HOMA-IR, TG, total cholesterol(TC) and T,FAI were higher(P<0.05) in Low-Vitamin D group than High-Vitamin D group. Postprandial plasma glucose(PPG) and postprandialplasma insulin(PINS) were higher(P<0.05) in Low-Vitamin D group than both High-Vitamin D group and Middle-Vitamin D group. Vitamin D was associated with BMI(r=-0.265, P=0.002), SBP(systolic blood pressure)(r=-0.267, P=0.002), HOMA-IR(r=-0.265, P=0.001),PINS(r=-0.252, P=0,002), TG(r=-0.265, P=0.001) and FAI(r=-0.211, P=0.027) in women with PCOS. However, after BMI was adjusted, vitamin D was no longer associated with these indexes. Vitamin D inoverweight/obese women with PCOS was lower than normal-weight women(P<0.05). Vitamin D was associated with DBP(r=-0.746,P=0.021) in overweight women with PCOS and was associated with PINS(r=-0.405,P=0.001)in obese women with PCOS.

Conclusion: Serum level of vitamin D was lower in women with PCOS than controls. Vitamin D in overweight/obese women with PCOS was lower than normal-weight women with PCOS. Vitamin D is associated with insulin resistance and cardiovascular disease risk in overweight/obese women with PCOS.