Dynamics of early childhood overweight

To study the dynamic processes that drive development of childhood overweight by examining the effects of prenatal characteristics and early-life feeding (breastfeeding versus bottle feeding) on weight states through age 7 years. We test a model to determine whether prenatal characteristics and early-life feeding influence the development of a persistent early tendency toward overweight and/or whether prenatal characteristics and early-life feeding factors influence the likelihood that children will change weight states as they get older.

Data from the National Longitudinal Survey of Youth's Child-Mother file were used to implement these analyses. A total of 3022 children were included in this sample. For inclusion in this sample, valid information on height and weight during 3 consecutive interviews when the child was aged 24 to 95 months as well as valid data on prenatal and birth characteristics were needed. The primary outcome measure was childhood overweight (BMI >95th percentile). Multivariate logistic models and first-order Markov models were estimated.

Early development of childhood overweight was associated with race, ethnicity, maternal prepregnancy obesity, maternal smoking during pregnancy, and later birth years. In later years, the factor that contributed the most to being overweight was having been overweight in the previous observation period. However, with conditioning on the child's having been overweight in the previous observation period, the prenatal factors that contributed to early childhood overweight, except for birth cohort, were also associated with development of overweight among children who had previously been normal weight and perpetuated the persistence of overweight over time.

This research suggests that prenatal characteristics, particularly race, ethnicity, maternal smoking during pregnancy, and maternal prepregnancy obesity, exert influence on the child's weight states through an early tendency toward overweight, which then is perpetuated as the child ages. These findings are intriguing as they provide additional clues to the genesis of childhood overweight and suggest that overweight prevention may need to begin before pregnancy and in early childhood.