The Independent and Cumulative Effect of Early Life Risk Factors on Child Growth: A Preliminary Report.

BACKGROUND: Early life risk factors may promote faster infant growth leading to childhood obesity. We examined growth patterns (birth to 12 months) and their association with early life risk factors.

METHODS: Participants were drawn from an ongoing birth cohort of 351 mothers. Child weight and length were obtained at birth, 6 weeks, and 3, 6, 9, and 12 months. Independent variables and demographics were tested as risk factors for inclusion in the cumulative risk score if they were significantly associated with change in weight-for-length z-scores (WFLZ; month 12 minus birth) or based on established evidence for an association with child growth. Multiple regression was used to determine the association of change in WFLZ with low maternal education, low month 3 postpartum maternal weight loss, and nonexclusive breastfeeding by month 3 (use of formula) or their cumulative risk. Trajectory groups were identified using semiparametric mixture models and their association with the risk factors and cumulative risk score was tested using logistic regression.

RESULTS: Nonexclusive breastfeeding by month 3 was associated with greater WFLZ increase. We identified three trajectory groups: low-rising (14.5%), mid-stable (59.4%), and high-rising (26.1%). Low-rising versus mid-stable group membership doubled with nonexclusive breastfeeding by month 3 (odds ratio [OR] = 2.24; 95% confidence interval [CI] = 1.05-4.80), but increased the most among children who had three risk factors compared to none (OR = 4.82; 95% CI = 1.14-20.32). No relationships were observed with high-rising growth.

CONCLUSIONS: Early life risk factors influence the development of growth trajectories during the first year in a cumulative fashion.