Determinants of Infant Growth: Evidence from Hong Kong's " Children of 1997" Birth Cohort

Purpose: A high rate of infant growth may be associated with adult cardiovascular disease. We investigated factors associated with infant weight growth in a large sample from the recently transitioned population of Hong Kong. Methods: We used a nonlinear shape invariant model with random effects among 5949 term, singletons (77% follow-up) from a population-representative Hong Kong Chinese birth cohort " Children of 1997" to investigate factors associated with weight growth in the first year of life. Results: Overall birth weight was lower but infant growth was more rapid than the 2006 WHO standards. Shorter gestation and lower birth order were associated with lower birth weight and faster infant growth. Female sex, maternal smoking in pregnancy, and a mother born in Hong Kong were associated with lower birth weight, but not with faster growth. Higher maternal education was associated with faster infant growth, grades 10-11 (1.03, 95% confidence interval [CI] = 1.03-1.05), greater than or equal to grade12 (1.07, CI = 1.04-1.09) compared with less than or equal to grade 9. Conclusions: Infant growth may respond more rapidly to socio-economic development than birth weight. Whether mother's education is associated with rapid infant growth via current conditions or her own " constitution" is unclear, nevertheless we believe this study illustrates the importance of contextually specific research for understanding the determinants of population health.