Association Between Physical Activity and Menopausal Symptoms in Perimenopausal Women

Min-Ju Kim; Juhee Cho; Younjhin Ahn; Gyeyoon Yim; Hyun-Young Park

Disclosures

BMC Womens Health. 2014;14(122) 

In This Article

Methods

Ethics Statement

The study was approved by the Institutional Review Board of the Kangbuk Samsung hospital (IRB No. KBC12156). Written informed consent was obtained from all subjects before they participated in the study.

Study Participants

The Kangbuk Samsung Health Study is a cohort study of South Korean men and women aged 18 years or older who underwent a comprehensive annual or biennial health examination at the clinics of the Kangbuk Samsung Hospital Total Healthcare Center in Seoul and Suwon, South Korea. This ancillary study was a cross-sectional observational study and its purpose was to investigate the attitudes of Korean women towards menopause. Among the middle-aged women who visited a healthcare center between November 2012 and March 2013, the subjects who agree to participate in this study were selected. The participation rate was about 71%. Inclusion criteria were age of 44–56 years, no serious illness, and the ability to understand a questionnaire. Subjects who were diagnosed with cancer and were being treated were excluded in the screening stage. In total, 2,204 healthy women were invited to participate in the study. The participants were divided into three groups according to menopausal status on the basis of Stages of Reproductive Aging Workshop (STRAW) criteria, as follows: premenopause is defined as having regular menstrual periods; perimenopause is characterized by persistent ≥ 7 days difference in length of consecutive cycles or interval of amenorrhea of ≥ 60 days; and postmenopause is the period after 12 consecutive months of amenorrhoea.[18] To investigate the influence of physical activity on perimenopause-associated symptoms, the 732 perimenopausal women were selected. Fifty subjects who had a history of hormone replacement therapy for the management of menopausal symptoms, 38 with missing data on their MENQOL questionnaire, 12 who responded 'no symptoms' for all items of the MENQOL, and one with missing information on physical activity were excluded from the analysis. Therefore, 631 women were eligible for this study.

Measurements

Body weight and height were measured to the nearest 0.1 kg or 0.1 cm and body mass index (BMI) was calculated as body weight (kg) divided by height (meters) squared. Waist circumference (WC) was measured at the midpoint between the lower ribs and the top of the iliac crest in the standing position. Blood pressure (BP) was measured three times with a Welch Allyn sphygmomanometer after a 5 min rest period and the average systolic and diastolic BP values of two measurements were calculated.

Blood samples were collected after at least a 10 h fast. Fasting plasma glucose (FPG), total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C) levels were measured enzymatically (Module Extention D2400, Roche, Japan). Hemoglobin A1C was evaluated using an immunoturbidimeter (Integra 800, Roche, Switzerland). The homeostatic model for insulin resistance (HOMA-IR) was calculated using the following formula: fasting insulin (μIU/mL) × fasting glucose (mg/dL)/(22.5 × 18).

Current smoking status was categorized as yes or no. Respondents who reported being married or cohabiting were categorized as living with a partner. Those reporting that they had never married or were separated, divorced or widowed were categorized as living without a partner. Family income was classified as < 4 million won and > 4 million won per month. Education level was categorized as high school or lower, or college/university. Parity was characterized as 1–2 children and 3 or more children.

Menopausal Symptoms

The MENQOL questionnaire was used to assess menopause-related symptoms.[19] This questionnaire consists of 29 items in four domains, namely, vasomotor (three items), psychosocial (seven items), physical (16 items) and sexual (three items), and the subjects were asked to indicate whether they had experienced each symptom and, if they had, to rate the symptom according to its severity from 0 (not at all bothered) to 6 (extremely bothered).[16] For data analysis, this seven-point Likert scale was converted to a score ranging from 1 (not experiencing a symptom) to 8 (extremely bothered).[16] The mean score of each domain was calculated separately. In order to d emonstrate the internal consistency of the four domains in the MENQOL, Cronbach's alpha coefficients were calculated. The coefficients were 0.81 for the vasomotor domain, 0.87 for the psychosocial domain, 0.88 for the physical domain, and 0.84 for the sexual symptoms domain, indicating that this scale had an acceptable reliability.

Physical Activity Assessment

The physical activity of the women was assessed using the International Physical Activity Questionnaire (IPAQ) short form.[20] This questionnaire asks about three specific types of activity, namely, walking, moderate-intensity activities, and vigorous-intensity activities.[20] The minutes spent every week on each type of activity are computed separately by multiplying the duration and frequency of activity.[20] A continuous activity score is calculated by multiplying the selected metabolic equivalent (MET) value and weekly minutes of activity, therefore expressing physical activity as MET-min per week.[20] The subjects were divided into low, moderate and high levels of physical activity on the basis of their total physical activity (MET-min/week) and the frequency of the activities.[20] The MET values and the level of physical activity were calculated according to the guidelines for data processing and analysis of the IPAQ.[20]

Statistical Analysis

Distribution testing for normality was performed using the Shapiro-Wilk test and the data were log-transformed to obtain normalized distributions. The geometric means of log-transformed variables were back-transformed for ease of interpretation and were expressed with 95% confidence intervals (CIs). The baseline characteristics of the study participants were expressed as mean ± standard deviation (SD), geometric mean (95% CI), or number (%). The low, moderate, and high physical activity groups were compared using one-way analysis of variance (ANOVA) with Dunnett's multiple comparison test for continuous variables and chi-square tests for categorical variables. The relationships between baseline characteristics and physical activity level were assessed using a linear-by-linear association test. The relationships between MENQOL total score/subscores and physical activity level were assessed using ANOVA with Dunnett's multiple comparison test. Because of missing data on marital status, family income and education, only 476 of 631 participants were included in the main analysis. The associations between physical activity and MENQOL total score/subscores were assessed by multiple linear regression analysis. MENQOL total score/subscore served as dependent variables, while physical activity level served as an independent variable. Adjustments were made for age, BMI, marital status, family income, education, and parity. The strength of the association between the total MENQOL score/subscores and the physical activity level was expressed as the beta coefficient and P-values. To assess the clinical significance of the result, the effect size was calculated.[21,22] P-values of <0.05 were considered to indicate statistical significance. All data were analyzed using SPSS Statistics 21 (SPSS Inc., IBM Corp., Chicago, IL, USA).

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