Vitamin D2026

Serum vitamin D levels in non-obese women with polycystic ovary syndrome: a systematic review and meta-analysis.

Jiang Mei, Wang Tan, Huang Ling — Frontiers in endocrinology

Summary

A new study reviewed existing research on vitamin D levels in women with polycystic ovary syndrome (PCOS) who are not obese. It found no significant difference in vitamin D levels between these women and healthy individuals. This suggests that vitamin D deficiency often linked to PCOS might be more closely related to obesity itself, rather than the syndrome's underlying mechanisms.

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Key points

This study examined vitamin D levels in non-obese women diagnosed with polycystic ovary syndrome (PCOS).
Researchers found no significant difference in vitamin D levels compared to healthy women.
The findings suggest that obesity, rather than PCOS itself, might be a primary factor contributing to vitamin D deficiency in women with the syndrome.

What the study looked at

What question the study asked: This systematic review and meta-analysis investigated whether non-obese women diagnosed with polycystic ovary syndrome (PCOS) have different blood vitamin D levels compared to healthy women. The goal was to provide a clearer picture, as previous studies on this specific group had yielded conflicting results regarding vitamin D status. How it was studied: Researchers conducted a comprehensive search across major scientific databases to identify relevant studies published up to May 2025. They included eleven studies that compared non-obese women with PCOS to healthy controls. A total of 533 non-obese PCOS patients and 574 healthy individuals were included in their statistical analysis, known as a meta-analysis, to combine and evaluate the findings. What it found: The combined analysis indicated that there were no significant differences in the levels of key vitamin D forms in the blood between non-obese women with PCOS and healthy women. This outcome suggests that vitamin D deficiency, often observed in women with PCOS, might be primarily driven by the presence of obesity rather than the underlying mechanisms of PCOS itself.

Dietary takeaway

This study suggests that for women with PCOS, maintaining a healthy weight might be particularly important for their vitamin D status. While this research focused on non-obese individuals, ensuring adequate vitamin D intake through foods like fatty fish and fortified dairy, along with safe sun exposure, remains crucial for everyone's overall health. It's important to remember that this is one review of existing studies, and more research is always needed to draw definitive conclusions.

Abstract

INTRODUCTION: Vitamin D deficiency is linked to increased risk of polycystic ovary syndrome (PCOS) and may worsen metabolic disorders such as insulin resistance. However, evidence remains inconsistent regarding vitamin D status in non-obese women with PCOS. This study aimed to perform the first systematic review and meta-analysis evaluating serum vitamin D levels in non-obese PCOS patients. METHODS: Relevant studies were searched in PubMed, Embase, Cochrane Library, and Web of Science up to May 2025. Eligible studies comparing non-obese PCOS women and healthy controls were included. Two reviewers independently screened articles. Meta-analysis was conducted using a random-effects model, supplemented by subgroup, sensitivity, and publication bias analyses. RESULTS: Eleven studies involving 533 non-obese PCOS patients and 574 controls were included. No significant differences were found in serum 25(OH)D or 1,25(OH)D levels between groups. Heterogeneity was mainly attributed to region, diagnostic criteria, BMI, and assay methods. Significant publication bias was detected. DISCUSSION: Serum vitamin D levels are not significantly associated with non-obese PCOS, implying vitamin D deficiency may be driven by obesity rather than PCOS pathogenesis. Vitamin D supplementation may benefit obese PCOS patients, and further prospective studies are needed. SYSTEMATIC REVIEW REGISTRATION: http://www.crd.york.ac.uk/PROSPERO, identifier CRD420251168257.

View on PubMed →DOI: 10.3389/fendo.2026.1839319