Study design and participants
This study utilized the data originated from the cross-sectional,
observational study, Estrogenic Regulation of Muscle Apoptosis
(ERMA) that investigates how hormonal differences over menopausal
stages affects the physiological and psychological functioning of
middle-aged women. The study data collection proceeded in three phases
described in detail in Kovanen et al.17 and in Figure
1. Briefly, written invitation was sent to 6878 randomly selected women
aged 47 to 55 years living in Central Finland. The response rate was
46.9%. In total, 3064 women were willing to participate in ERMA Phase 1
and, in addition to written consent, they returned prequestionnaire
which included questions on symptoms of pelvic floor disorders.
Thereafter, the exclusion criteria included conditions or use of
medications affecting ovarian function, obesity (self-reported body mass
index [BMI] > 35 kg/m2), and chronic
diseases or medications affecting muscle function. From the eligible
participants (n=1627), 1393 gave fasting blood samples (Phase 2) and
1102 of them answered to the main questionnaire survey (Phase 3). The
sample size of the present study is 1098, since four main questionnaires
were lost due to technical error. The study protocol followed good
clinical and scientific practice and the Declaration of Helsinki and was
approved by the Ethics Committee of the Central Finland Health Care
District (KSSHP Dnro 8U/2014).