Adiposity and the development of premenstrual syndrome.

Moderate to severe premenstrual syndrome (PMS) affects 8%-20% of premenopausal women and causes substantial levels of impairment, but few modifiable risk factors for PMS have been identified. Adiposity may impact risk through the complex interaction of hormonal and neurochemical factors, but it is not known if adiposity increases a woman's risk of developing PMS. We have addressed these issues in a prospective study nested within the Nurses' Health Study 2. Participants were a subset of women aged 27-44 and free from PMS at baseline, including 1057 women who developed PMS over 10 years of follow-up and 1968 controls. Body mass index (BMI), weight change and weight cycling were assessed biennially via questionnaire. We observed a strong linear relationship between BMI at baseline and risk of incident PMS, with each 1 kg/m(2) increase in BMI associated with a significant 3% increase in PMS risk (95% confidence interval [CI] 1.01-1.05). After adjustment for age, smoking, physical activity, and other factors, women with BMI ≥ 27.5 kg/m(2) at baseline had significantly higher risks of PMS than women with BMI < 20 kg/m(2) (p(trend) = 0.003). A large weight change between age 18 and the year 1991 was significantly associated with PMS risk, whereas weight cycling during this period was not. BMI was positively associated with specific symptoms, including swelling of extremities, backache, and abdominal cramping (all p < 0.001). Our findings suggest that maintaining a healthy body mass may be important for preventing the development of PMS. Additional studies are needed to assess whether losing weight would benefit overweight and obese women who currently experience PMS.