Relationship between the frequency of menstrual pain and bodyweight in female adolescents

Purpose: Many female adolescents suffer menstrual pain and their daily activities are often adversely affected. It is, therefore, necessary to clarify what factors are associated with menstrual pain in order to assist in improving their quality of life (QOL). The purpose of the present study was to examine if adolescents' physique, which reflects their diet and physical activities, has any influence on the frequency of menstrual pain. Especial attention was concentrated on the Body Mass Index (BMI).

Subjects and methods: Using a cross-sectional sample of 2,718 college women aged 18 to 21, both a measurement of body weight and height and a survey with a self-administered questionnaire were carried out in April 2000. The data for the 2,282 college women who properly answered questions were analyzed to study the association of the frequency of menstrual pain with age, physique, exercising habits and factors associated with menstruation such as menarcheal age, menstrual cycle, menstrual duration and menstrual flow.

Results: Of the 2,282 college women studied, 34.1% regularly experienced menstrual pain, 48.7% sometimes and 17.2% seldom. When the college women studied were divided into three groups according to an old definition of obesity by Nippon Himan Gakkai, 34.8% of them belonged to the underweight group (BMI < 19.8), 53.8% to the normal group (19.8 < or = BMI < 24.2) and 11.4% were overweight (BMI > or = 24.2). Logistic analysis showed the odds ratio (OR) for the underweight group regularly experienced menstrual pain to be 1.3 (95% confidence intervals (CI): 1.1-1.6) while that for the overweight group was 1.1 (95% CI: 0.8-1.5), taking the normal group as the reference. Early menarche and heavy menstrual flow increased the risk of experiencing menstrual pain while irregular menstrual cycle was associated with decrease.

Conclusion: The prevalence of menstrual pain among the college women studied was very high, 82.8%, the frequency being greatest in the underweight group (BMI < 19.8). Given the current trend for young women to wish to be thin and the fact that nearly half of Japanese females aged 15 to 24 are already lean, this study suggests that it is very important to take measures to counteract young women's enthusiasm for excessive dieting or other approaches to weight loss since this will help reduce their menstrual pain and improve their QOL.