Background:There have been few population-based studies on the relationships between physical activity (PA) and menstrual symptoms, as most research to date has focussed on athletes.
Methods:Participants in The Australian Longitudinal Study of Women’s Health (age 22-27 in 2000) completed mailed surveys in 1996, with follow-ups in 2000, 2003, 2006, 2009, 2012 and 2015. They reported their PA levels, height and weight, and the frequency of irregular periods and heavy menstrual bleeding (HMB) in each survey. Generalised estimating equation population-averaged model analyses were conducted to calculate odds ratios (OR) and 95% confidence intervals (95% CIs) for the associations between PA and BMI with menstrual symptoms using data from 10618 women.
Results:The prevalence of irregular periods (19.4% at age 22-27) remained stable over 15 years; there were no associations between PA and irregular periods. Odds were higher in women who were overweight [OR 1.08, (95%CI 1.00-1.17)] or obese [OR 1.29, (95%CI 1.18-1.41)] than in women with healthy weight.
The prevalence of HMB (15.9% at age 22-27) doubled over 15 years and was consistently highest in women in the lowest PA category. Women who were highly active had 10% lower odds [OR 0.90, (95%CI 0.82-0.98)] than women who did no PA. Overweight and obese women had higher odds [overweight: OR 1.15, (95%CI 1.07-1.23); obese: OR 1.37, (95%CI 1.26-1.49)] of HMB than women with healthy weight. Among obese women, there was a 19% [OR 0.81,(95%CI 0.68-0.97)] reduction in the odds of HMB in those who reported high PA.
Conclusions:Menstrual symptoms are positively associated with BMI. However, the adverse effects of high BMI on HMB were attenuated byhigh levels of PA. While intervention studies are needed to confirm associations between PA and menstrual symptoms, these data suggest that promotion of PA at this life stage is important for reproductive health.