Full breast-feeding for at least four months has differential effects on growth before and after six months of age among children in a Mexican community
Cl. Eckhardt et al., Full breast-feeding for at least four months has differential effects on growth before and after six months of age among children in a Mexican community, J NUTR, 131(9), 2001, pp. 2304-2309
This study examines the relationship between breast-feeding and growth from
0 to 6 and 6 to 20 mo among 185 children in a Mexican community. Infants f
rom a previous 6-mo longitudinal study were followed up for additional anth
ropometric measurements at a mean age of 19.9 mo. Size at 6 mo and at follo
w-up were modeled as outcomes of whether infants were fully breast-fed (exc
lusively or predominantly breast-fed) for at least 4 mo, controlling for si
ze at birth and 6 mo, respectively, and potential confounders. From birth t
o 6 mo, fully breast-fed infants had ponderal index increments of 0.07 unit
s larger (P = 0.04) than comparison infants. There were no differences in w
eight. For length, an interaction between full breast-feeding and socioecon
omic status (SES) was found, with fully breast-fed infants of low SES growi
ng more than comparison infants, whereas the opposite was seen at upper SES
levels. From 6 to 20 mo, fully breast-fed infants had weight and length in
crements of 0.53 cm (P < 0.001) and 0.72 kg (P = 0.01) smaller than those o
f comparison infants. For ponderal index, an interaction between mother's e
ducation and breast-feeding revealed an inverted U-shaped response across l
evels of education. Additionally, logistic regressions of monthly breast-fe
eding on lagged measurements revealed that relatively heavier infants had h
igher odds of being fully breast-fed at 2 and 3 mo. Our findings indicate t
hat the benefits of full breast-feeding on growth may be most pronounced ea
rly in life. Further research of unmeasured confounders may explain the ass
ociation of full breast-feeding with slower growth beyond 6 mo.