BACKGROUND: In women, adhering to an overall healthy lifestyle is associated with a dramatically reduced risk of cardio-metabolic disorders. Whether such a healthy lifestyle exerts an intergenerational effects on child health deserves examination.

METHODS: We included 5701 children (9-14 years old at baseline) of the Growing Up Today Study 2, and their mothers, who are participants in the Nurses' Health Study II. Pre-pregnancy healthy lifestyle was defined as a normal body mass index, no smoking, physical activity ≥150 min/week, and diet in the top 40% of the Alternative Healthy Eating Index-2010. Obesity during childhood and adolescence was defined using the International Obesity Task Force age- and sex-specific cutoffs. Multivariable log-binominal regression models with generalized estimating equations were used to evaluate the association of pre-pregnancy healthy lifestyle and offspring obesity.

RESULTS: We identified 520 (9.1%) offspring who became obese during follow-up. A healthy body weight of mothers and no smoking before pregnancy was significantly associated with a lower risk of obesity among offspring: the relative risks [RRs; 95% confidence intervals (CIs)] were 0.37 (0.31-0.43) and 0.64 (0.49-0.84), respectively. Eating a healthy diet and regular moderate-to-vigorous physical activities were inversely related to offspring obesity risk, but these relations were not statistically significant. Compared to children of mothers who did not meet any low-risk lifestyle factors, offspring of women who adhered to all four healthy lifestyle factors had 75% lower risk of obesity (RR: 0.25, 95% CI: 0.14-0.43).

CONCLUSION: Adherence to an overall healthy lifestyle before pregnancy is strongly associated with a low risk of offspring obesity in childhood, adolescence, and early adulthood. These findings highlight the importance of an overall healthy lifestyle before pregnancy as a potential strategy to prevent obesity in future generations.