Determinants of Growth From Birth to 12 Months Among Breast-Fed Honduran Infants in Relation to Age of Introduction of Complementary Foods

摘要

Objectives . To evaluate the impact of introducing complementary foods to exclusively breast-fed infants at 4 vs 6 months on growth from 6 to 12 months, and to compare growth patterns of Honduran infants with those of breast-fed infants in the United States.Design . Randomized intervention trial from 4 to 6 months and longitudinal study of infants from birth to 12 months.Setting . Low-income communities in San Pedro Sula, Honduras.Subjects . Primiparous, breast-feeding mothers and their infants (n = 141) recruited from public maternity hospitals.Intervention . Infants were randomly assigned to exclusive breast-feeding to 6 months, or exclusive breast-feeding with addition of hygienically prepared, nutritionally adequate complementary foods at 4 months, with or without maintenance of baseline breast-feeding frequency. After 6 months, mothers continued to breast-feed and also fed their infants home-prepared foods after receiving instruction in appropriate feeding practices.Outcome Measures . Infant weight was measured monthly during the first year of life and infant length monthly from 4 to 12 months.Statistical Analysis . Growth parameters were compared between the Honduran and US cohorts using multiple-regression and repeated-measures analysis of variance. Stepwise multiple regression was used to identify determinants of infant growth.Results . There were no differences in growth patterns by intervention group. Mean birth weight of the Honduran infants was significantly less than that of a cohort of breast-fed infants in an affluent US population (n = 46) (2889 ± 482 vs 3611 ± 509 g), but the Honduran infants exhibited rapid catch up in weight in the first few months of life, and the cohorts were similar in weight by 3 months. Mean weight and length gain were similar to those of the US cohort from 4 to 9 months but were lower from 9 to 12 months. Mean length for age was significantly less than that of the US cohort from 4 to 12 months; this was attributable to the difference in maternal height (12 cm shorter in Honduras on average). Within the Honduran cohort, growth velocity of low birth weight infants (2500 g; n = 28) was similar to that of their normal birth weight peers; thus, the former subgroup remained smaller than the latter throughout the first year of life.Conclusions . In poor populations, when breast-feeding is exclusive for the first 4 to 6 months, continues from 6 to 12 months, and is accompanied by generally adequate complementary foods, faltering in weight does not occur before 9 months among infants born with birth weights of more than 2500 g.