Objective: To investigate the effect of undertaking lifestyle interventions during periods of seasonal change on vitamin D status and health outcomes in overweight/obese women with polycystic ovary syndrome (PCOS).
Design: Retrospective, unplanned secondary analysis of two cohorts during different seasons.
Setting: Outpatient clinical research unit.
Patient(s): Fifty overweight/obese women with PCOS.
Intervention(s): Twenty-week lifestyle modification program (Clinical Trials registration no.: ACTRN12606000198527); one cohort started in winter and finished in summer, and one started in summer and finished in winter.
Main outcome measure(s): 25-Hydroxyvitamin D (25OH-D), weight, waist circumference (WC), body composition, cardiovascular disease (CVD) risk factors, and menstrual cycle length.
Result(s): Baseline 25OH-D levels were 27.6 ± 9.0 nmol/L. The winter cohort had lower 25OH-D levels at baseline, which increased over 20 weeks, whereas the summer cohort started with higher levels which decreased. Changes in 25OH-D were inversely correlated with changes in WC and cholesterol when controlling for baseline values, such that increases in 25OH-D were associated with greater reductions in WC and cholesterol.
Conclusion(s): Obesity and CVD risk profiles improved in vitamin D-deficient women with PCOS after a 20-week lifestyle intervention during which vitamin D status improved with seasonal change.
Clinical trial registration number: ACTRN12606000198527.
Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.