Early life exposure to behavioral risk factors of obesity and subsequent weight among preschool-aged children in Los Angeles

Early weight gain and obesity in children can alter their health trajectory over the life course. Yet, few studies examined the effect of early life weight (as indicated by weight-for-height-Z score [WHZ]) on subsequent WHZ among pre-school-aged children using appropriate methods accounting for time-varying covariates. Additionally, obesity involves multiple risk factors, which taken individually may not be as potent as when they occur concurrently. We used linear regression and the g-formula to estimate the total and joint effect of early WHZ and the total effect of a behavioral risk factor index on end-of-follow-up WHZ. We used data from the Special Supplemental Nutrition Program for Women, Infants and Children (WIC). Survey data obtained in 2008 were linked to WIC administrative data to follow 1820 low-income preschool-aged children in Los Angeles County from 2008 to 2010.The child’s WHZ in 2010 increased by a mean of 0.53 (95%CI: 0.49; 0.57) as early WHZ (2008) increased one unit. The joint total effect for every one unit increase in the first WHZ measurement (2008) and the subsequent WHZ measurement (2009) on the end-of-follow-up (2010) WHZ is about 0.81 (95%CI: 0.77; 0.86). Watching TV, playing in playgrounds, consuming sugar-sweetened-beverages, eating fruits and vegetables, eating fast-foods did not appear to alter the child’s WHZ at the end-of-follow-up. However, breastfeeding for at least six months was protective (adjusted mean difference -0.16, 95%CI: -0.32; -0.02) as well as having a high score on the behavioral risk factor index (-0.21, 95%CI: -0.34; -0.08). Early weight gain plays an important role in determining subsequent weight. Tackling weight gain and multiple risk factors simultaneously early in life are important strategies for preventing obesity later in life.