Association between sex steroids, ovarian reserve, and vitamin D levels in healthy nonobese women

Abstract

Context: Vitamin D maintains calcium and phosphorous homeostasis and promotes bone mineralization; however, its nonskeletal functions are increasingly being recognized. Recent evidence supports a role for vitamin D in reproductive potential, but few studies have investigated the potential effects of vitamin D on reproductive hormone biosynthesis and ovarian reserve. Objective: The aim of this study was to determine the relationships between the serum level of vitamin D, reproductive hormone levels, and ovarian reserve in healthy nonobese women. Design: This was a cross-sectional study. Setting: The study was performed at the Fertility Center at CHA Medical Center. Participants: Seventy-three healthy women volunteers participated in this study. The participants were nonobese parous women with regular menstrual cycles and no history of infertility. Main Outcome Measures: Wedetermined serum levels of vitamin D, steroid hormones, SHBG, ovarian reserve markers, homeostatic model assessment of insulin resistance index, and lipid profiles. Results: In linear regression analysis adjusting for age, body mass index, homeostatic model assessment of insulin resistance, and lipid profile, serum vitamin D level positively correlated with total T (P < .001) and free androgen index (P