Development of overweight associated with childbearing depends on smoking habit: The Coronary Artery Risk Development in Young Adults (CARDIA) Study.
OBJECTIVE
To prospectively evaluate whether childbearing leads to development of overweight in women and to evaluate the role of other known risk factors.


METHODS
A prospective, multicenter observational study, the Coronary Artery Risk Development in Young Adults (CARDIA) Study from 1986 to 1996, examined subjects at baseline and in follow-up years 2, 5, 7, and 10. Included were 998 (328 black and 670 white) nulliparous women, age 18-30 years, who were not overweight at baseline. Relative odds for incident overweight (BMI > or = 25 kg/m2) associated with parity change (0, 1, or 2+) and risk factors were estimated using discrete-time survival models adjusted for baseline and time-dependent covariates.


RESULTS
Parity change-association with development of overweight depended on smoking habit (interaction, p < 0.001). In multivariate adjusted models, 1 and 2+ births vs. 0, respectively, were associated with increased risk for development of overweight among never smokers [odds ratio (OR) = 2.66; 95% confidence interval (CI): 1.80, 3.93, and 2.10, 95% CI: 1.24, 3.56] and decreased risk among current smokers (OR = 0.41; 95% CI: 0.17, 0.96, and 0.36, 95% CI: 0.08, 1.65). Risk was increased for black vs. white race (OR = 3.49; 95% CI: 2.59, 4.69), frequent weight cycling (OR = 1.45; 95% CI: 1.03, 2.04), and high school education or less (OR = 2.21; 95% CI: 1.50, 3.26) and was decreased for highest physical activity quartile (OR = 0.62; 95% CI: 0.43, 0.90).


CONCLUSIONS
Childbearing contributes to development of overweight in nonsmokers but not in smokers, where development of overweight is less likely in women who bear children. Race, education, and behaviors are important factors in development of overweight in young women.
Gunderson
Erica P
EP
Epidemiology and Prevention Section, Division of Research, Kaiser Permanente, 2000 Broadway, Oakland, CA 94612, USA. epg@dor.kaiser.org
Quesenberry
Charles P
CP
Lewis
Cora E
CE
Tsai
Ai-Lin
AL
Sternfeld
Barbara
B
Smith West
Delia
D
Sidney
Steve
S
D000293:Adolescent; D000328:Adult; D001519:Behavior; D044383:Black People; D015992:Body Mass Index; D003327:Coronary Disease / Q000209:etiology*; D004522:Educational Status; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D009765:Obesity / Q000453:epidemiology* / Q000209:etiology*; D016017:Odds Ratio; D010298:Parity; D011247:Pregnancy; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D044465:White People