Early anthropometric measures and reproductive factors as predictors of body mass index and obesity among older women.

OBJECTIVE

To examine whether early anthropometric measures and reproductive factors were associated with body mass index (BMI), overweight, and obesity.

DESIGN

Cross-sectional, observational study.

SUBJECTS

In all, 18 109 healthy women who participated in the Swedish Mammography Cohort aged 49-83 y.

MEASUREMENTS

Early anthropometric (birthweight and body shape at age 10 y) and reproductive (age at menarche, age at the birth of the first child, and parity) variables were our predictors and current BMI, overweight (BMI 25-29.99 kg/m(2)), and obesity (BMI > or =30 kg/m(2)) were our outcomes.

RESULTS

In multivariate-adjusted polytomous logistic regression analysis, risk of overweight and obesity increased with increasing body shape at age 10 y and decreased with increasing age at menarche and age at first birth (P for trend <0.0001). A U-shaped relation with birthweight was observed. In our tests for effect modification of the relation with overweight/obesity (ow/ob; BMI > or =25 kg/m(2)), we detected significant interactions between body shape at 10 y and age (P<0.0001); body shape at 10 y and physical activity (P<0.0001); age at first birth and smoking (P=0.02); and parity and physical activity (P=0.004). The increased risk of ow/ob among women who reported a larger childhood body shape was reduced as women moved from the lowest to highest quartile of physical activity in adulthood. Likewise, the increasing risk of ow/ob among women with greater parity was reduced with increased physical activity.

CONCLUSION

Early anthropometric measures and reproductive factors are significantly associated with BMI, overweight, and obesity among older women. The effects of childhood body weight, age at first birth, and parity may be modified by adult lifestyle choices, as well as age.