title: Low serum 25-hydroxyvitamin D concentrations are associated with insulin resistance and obesity in women with polycystic ovary syndrome.
abstract: Insulin resistance (IR) and central obesity are common features of the polycystic ovary syndrome (PCOS). Vitamin D is thought to play a role in the pathogenesis of type 2 diabetes by affecting insulin metabolism. The aim of our study was to investigate the effect of 25-hydroxyvitamin D (25-OH-VD) on metabolic parameters and IR in PCOS. In 120 untreated PCOS patients (median age 28 years) levels of 25-OH-VD (radioimmunoassay method provided by DiaSorin), calcium and anorganic phosphate were measured. In addition, endocrine and metabolic variables were evaluated and a glucose tolerance test was performed to assess indices of IR. In the entire PCOS cohort, 25-OH-VD concentrations were negatively correlated with body mass index (r=-0.2765), body fat (r=-0.2490), HOMA-IR (r=-0.1947), hyperinsulinemia (r=-0.1892) and leptin levels (r=-0.2834), and positively correlated with HDL cholesterol (r=0.2630) (all p<0.05). Subgroup analysis of lean, overweight and obese women revealed significant higher 25-OH-VD levels in lean women. Differences remained significant when women were divided according to their 25-OH-VD levels. Women with hypovitaminosis D (<9 ng/ml) had higher mean BMI, indices of IR and leptin levels compared to women with normal serum levels (all p<0.05). Analysis of vitamin D and biochemical endocrine PCOS features revealed a significant correlation only between 25-OH-VD and sex hormone-binding globulin as well as the free androgen index. In conclusion, in PCOS women, low 25-OH-VD levels are associated with obesity and insulin resistance but not with PCOS per se.
authors.affiliation: Endokrinologikum Ruhr, Center for Metabolic and Endocrine Diseases, Bochum, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Hahn
authors.forename: U
authors.initials: U
authors.lastname: Haselhorst
authors.forename: S
authors.initials: S
authors.lastname: Tan
authors.forename: B
authors.initials: B
authors.lastname: Quadbeck
authors.forename: M
authors.initials: M
authors.lastname: Schmidt
authors.forename: S
authors.initials: S
authors.lastname: Roesler
authors.forename: R
authors.initials: R
authors.lastname: Kimmig
authors.forename: K
authors.initials: K
authors.lastname: Mann
authors.forename: O E
authors.initials: OE
authors.lastname: Janssen
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D017588:Hyperandrogenism / Q000453:epidemiology; D007333:Insulin Resistance; D009765:Obesity / Q000097:blood* / Q000150:complications; D011085:Polycystic Ovary Syndrome / Q000097:blood*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D