Vitamin D Levels in Women with Polycystic Ovary Syndrome: A Population-Based Study

Abstract

Background: Conflicting evidence supports a role for vitamin D in women with reproductive disorders such as polycystic ovary syndrome (PCOS) but studies on large, unselected populations have been lacking. Methods: We conducted a general population-based study from the prospective Northern Finland Birth Cohort 1966 (NFBC1966). Serum 25-hydroksyvitamin D (25(OH)D) levels were evaluated in women with self-reported PCOS (n = 280) versus non-symptomatic controls (n = 1573) at the age of 31 with wide range of endocrine and metabolic confounders. Results: The levels of 25(OH)D were similar among women with and without self-reported PCOS (50.35 vs. 48.30 nmol/L, p = 0.051). Women with self-reported PCOS presented with a higher body mass index (BMI), increased insulin resistance, and low-grade inflammation and testosterone levels compared to controls. The adjusted linear regression model showed a positive association between total 25(OH)D levels in self-reported PCOS (β = 2.46, 95% confidence interval (CI) 0.84 to 4.08, p = 0.003). The result remained after adjustment for BMI, testosterone, homeostatic model assessment of insulin resistance (HOMA-IR), and high-sensitivity C-reactive protein (hs-CRP) levels. Conclusion: In this population-based setting, PCOS was associated with higher vitamin D levels when adjusting for confounding factors, without distinct beneficial effects on metabolic derangements.

Mechanisms Involved in the Relationship between Vitamin D and Insulin Resistance: Impact on Clinical Practice

“…However, in subjects from the AMIGOS trial, no significant association was observed between 25(OH)D deficiency and live births. The study of Lumme et al, which included 1246 women, showed that women with PCOS were no more prone to vitamin D deficiency than non-symptomatic controls, since a considerable number of women in both groups had low 25(OH)D levels with mean 25(OH)D concentrations above the normal range in participants with selfreported PCOS [179]. Nevertheless, the authors of this paper recommend that sufficient vitamin D levels should be ensured in women with PCOS, especially in overweight and obese women.…”

The determinants and longitudinal changes in vitamin D status in middle-age: a Northern Finland Birth Cohort 1966 study

“…The study population was derived from a prospective, general population-based birth cohort, the Northern Finland Birth Cohort 1966 (NFBC1966). This cohort has been described in detail elsewhere [ 21 , 22 ], including two studies about VitD [ 23 , 24 ]. In this study, we included the cohort participants who attended both the 31-year (1997) and 46-year (2012–2013) clinical follow-ups, before and during NNC launched food fortification programme (Fig.…”

“…We tested for marital status, physical activity, smoking, alcohol consumption, occupational and education variables and their relevant two-way interactions in the model, but no interaction was found, and their effects did not change the estimates of the other variables in the model. As a sensitivity analysis, we ran a similar regression analysis including the outlier data and an another with exclusion of females using oral contraceptives and hormonal replacement therapy (Online resource 2), since there is evidence for a difference in 25(OH)D among this group [ 23 , 24 ].…”

Polycystic ovary syndrome: new insights on the puzzle of adiposity, chronic low-grade inflammation and metabolic disturbances

“…However, even if its nuclear receptor (VDR) is observed in many tissues, including the ovary, the exact mechanism of action of vitamin D has yet to be established in PCOS. Previous trials addressing its circulating levels have shown lower, similar or higher serum concentrations in women with PCOS (12,(14)(15)(16).…”

“…In another recent study addressing the prevalence of vitamin D deficiency in women with PCOS and different phenotypes, those presenting androgen excess had higher crude odds ratio for vitamin D deficiency, but the significance was lost after adjustment for BMI and ethnicity (18). Indeed, considering that obesity has been linked to lower serum vitamin D levels (19) and women with PCOS present higher prevalence of overweight/obesity as well as insulin resistance, assessing a potential independent role of vitamin D in PCOS still remains a challenge (14).…”