Strengths and limitations
The present study had several strengths. It was conducted in a large homogenous cohort of relatively healthy Finnish women, which permits precise measurements without a need to control potential confounders (e.g. ethnicity, health or income). On the contrary, our results may not be generalizable to more heterogenous populations. Unique to our study was the exact determination of menopause status of the participants by FSH measurements and menstrual bleeding diaries. This enabled us to adjust the models with menopause status, and reliably evaluate its association with pelvic floor disorders. Furthermore, the extend of this study is exceptional: five different pelvic floor disorders were studied among the large observational cohort including retrospective data for early adulthood physical activity.
The study had also some limitations. The experienced symptoms of pelvic floor disorders were asked by postal query in an early stage of the study. We were not able to study if this timing has influenced the willingness of the participants to report the conditions that may be considered sensitive. In addition, the threshold to report pelvic floor disorders may vary, since the manner women experience symptoms most likely differs from person to person, and the symptoms may also remain unrecognized.23,24
Pelvic floor disorders have been associated with higher BMI,25,26,27 however, women with BMI>35 kg/m2 were excluded from the analytical study sample, thus the results cannot be generalized to severely obese individuals. However, there were no obvious difference in the prevalence of any type of pelvic floor disorder among large Phase 1 study sample in which BMI was not exclusion criteria and among the analytical sample. Another limitation is that previous and current physical activity were self-reported, which may result some recalling or reporting bias by underestimating the number of low and overestimating the number of high physically active participants.28