Seasonal effects on vitamin D status influence outcomes of lifestyle intervention in overweight and obese women with polycystic ovary syndrome.
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).


METHODS
Retrospective, unplanned secondary analysis of two cohorts during different seasons.


METHODS
Outpatient clinical research unit.


METHODS
Fifty overweight/obese women with PCOS.


METHODS
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.


METHODS
25-Hydroxyvitamin D (25OH-D), weight, waist circumference (WC), body composition, cardiovascular disease (CVD) risk factors, and menstrual cycle length.


RESULTS
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.


CONCLUSIONS
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.


BACKGROUND
ACTRN12606000198527.
Nutritional Physiology Research Centre, Sansom Institute for Health Research, University of South Australia, South Australia, Australia. rebecca.thomson@unisa.edu.au
Rebecca L
RL
Thomson
Simon
S
Spedding
Grant D
GD
Brinkworth
Manny
M
Noakes
Jonathan D
JD
Buckley
D000328:Adult; D015331:Cohort Studies; D015536:Down-Regulation / Q000502:physiology; D005260:Female; D006801:Humans; D008019:Life Style; D009765:Obesity / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D050177:Overweight / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D011085:Polycystic Ovary Syndrome / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D012189:Retrospective Studies; D012621:Seasons; D015854:Up-Regulation / Q000502:physiology; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D055815:Young Adult
D014807:Vitamin D