Trajectories of BMI z-score from Birth to Adolescence and Their Maternal, Socioeconomic, and Environmental Risk Factors

Introduction: The life course perspective suggests factors acting early in life accumulate and/or interact with later-life factors to influence health. To date there have been two studies that have looked at risk factors associated with atypical growth patterns in childhood, but neither examined growth during both early childhood and adolescence. The purpose of this study is to identify potential maternal, socioeconomic, and environmental risk factors that distinguish children with high-rising body mass index (BMI) z-score trajectories, from birth to adolescence. Methods: This study employs a longitudinal, birth cohort in rural upstate New York (n=520). The exposures include variables pertaining to maternal mental and physical health, breastfeeding, family income trajectory, and middle school environment. The outcome, BMI z-score trajectory, was derived using measured heights and weights from birth to 14 years. The trajectories were classified using latent-class modeling, which grouped children based on their similar growth trajectories. Logistic regression with backward stepwise elimination was used to examine the risk factors that distinguish membership in the atypical trajectories. Results: Four trajectories in BMI z-score were identified: never-overweight (49.1%); overweight stable (20.3%); high-rising overweight (17.2%); and high-rising obese (13.4%). Preliminary models suggest an association between high-rising overweight and obese trajectories with high maternal BMI, high birth weight, low-income, food insecurity at age 2, and maternal smoking during pregnancy. Conclusions: This study suggests that maternal characteristics during pregnancy as well as social characteristics throughout childhood have a long lasting impact on high-rising BMI z-score trajectories.