Date Published: December 4, 2018
Publisher: Public Library of Science
Author(s): Y. H. M. Krul-Poel, P. P. Koenders, R. P. Steegers-Theunissen, E. ten Boekel, M. M. ter Wee, Y. Louwers, P. Lips, J. S. E. Laven, S. Simsek, Ramesh Narayanan.
To compare vitamin D status in women with PCOS versus fertile women and subsequently evaluate the association between vitamin D status and metabolic disturbances in PCOS women.
We conducted a cross-sectional comparison study of 639 women with PCOS and 449 fertile women. Serum 25-hydroxyvitamin D (25(OH)D) was stratified into a severe deficient (< 25 nmol/l), insufficient (25–50 nmol/l), moderate (50–75 nmol/l) and adequate (> 75 nmol/l) status. The main outcome measures were the difference in vitamin D status between PCOS and fertile women, and the association between serum 25(OH)D and metabolic disturbances in PCOS women only.
Serum 25(OH)D was significantly lower in PCOS women compared to fertile controls (mean 25(OH)D of 49.0 nmol/l versus 64.5 nmol/l). An adjusted significant difference was seen between serum 25(OH)D and homeostasis model assessment (HOMA-IR) (β = 0.76; 95% CI: 0.63–0.91; p < 0.01), HDL-cholesterol (β = 0.20; 95% CI: 0.05–0.60, p < 0.01) and apolipoprotein A1 (β = 26.2; 95% CI: 7.5–45.0, p < 0.01) between the highest vitamin D group compared to the lowest vitamin D group. This study demonstrates that women with PCOS have a significantly lower serum 25(OH)D compared to fertile controls. A compromised vitamin D status in PCOS women is associated with a higher HOMA-IR and an unfavourable lipid profile. Large randomized controlled trials are necessary to explore the causality of this linkage.
Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of reproductive age, with a prevalence up to 10% depending on which diagnostic criteria are used . It is characterized by ovulatory dysfunction, hyperandrogenism and/or polycystic ovarian morphology . Metabolic disturbances are present in a majority of the women suffering from PCOS, i.e. 30–40% have impaired glucose tolerance and insulin resistance with compensatory hyperinsulinemia, and as many as 10% will develop type 2 diabetes mellitus during their fourth decade . Adipose tissue dysfunction has been implicated as a contributor to insulin resistance in women with PCOS. However, a substantial number of lean women affected by PCOS have insulin resistance as well, independent of obesity [4,5].
The aim of this study was 1) to explore vitamin D status in women with PCOS compared to fertile controls and 2) to evaluate the associations between vitamin D status and metabolic disturbances in PCOS women. In this study the lower vitamin D status in women with PCOS compared to fertile controls was confirmed . Low serum 25(OH)D status is significantly associated with a higher insulin resistance in women with PCOS independent of major confounders as BMI, season and ethnicity. Moreover, women with PCOS and a severe vitamin D deficiency had the lowest levels of HDL cholesterol and apolipoprotein A1.