Parity and body weight in the United States: differences by race and size of place of residence.

Objective: In women, parity has been studied in relation to body weights. This study examined whether and how relationships between parity and body weight differ by race and size of place of residence, adjusting for sociodemographic factors (age, income, education, working status, and marital status) and health behaviors (alcohol consumption, birth control pills, diet, physical activity, and smoking).

Methods: A U.S. national sample of 3398 white and black women from the Third National Health and Nutrition Examination Survey was used to study the relationships using multiple linear regression analysis.

Results: The parity-weight relationships varied by race and size of place of residence. After adjusting for the covariates, significant relationships between parity and body weight were found only in black women in metropolitan areas and white women in non-metropolitan areas. Compared with women with no children, white women with two children living in non-metropolitan areas tended to have lower BMIs, whereas black women in metropolitan areas with one or two children showed higher BMIs.

Conclusions: Overall, the parity-weight relationships in these groups of women were not strong or linear. The parity-weight relationships of black women in non-metropolitan areas warrant further examination.