Early growth faltering of rural Mesoamerindian breast-fed infants

Early growth faltering has been described in breast-fed infants 4-6 months of age from less-developed communities. The timing and magnitude of growth faltering, however, depends on the appropriateness or comparability of the reference used to evaluate growth performance. In this paper we compared the growth performance of a group of rural Mesoamerindian breast-fed infants from birth through 6 months of age to that of a reference group of breast-fed infants reared under favourable nutritional and environment conditions in the United States. The validity of this assessment is based upon the comparability of infant feeding mode. Mean weights and lengths and corresponding weight-for-age and length-for-age percentiles and z-scores were significantly lower among the Mesoamerindian (Otomi Indian) infants (p = 0.001). Mean weight-for-length percentiles and z-scores did not differ between groups. Weight gain (g/day) was significantly lower among the Otomi infants throughout the entire 6 months (p = 0.001). Length velocities of the Otomi infants were lower than reference infants at 3-6 months (p = 0.001). The growth pattern of the Otomi infants differed from that of the reference group: decreases in growth velocities and weight-for-age and length-for-age z-scores were significantly more precipitous for the Otomi infants between 4 and 6 months of age (p = 0.001). We conclude that growth faltering was evident among the Otomi infants between 4 and 6 months of age, relative to a reference growth of breast-fed infants.