Birthweight distributions in Mexico City and among US Southwest Mexican Americans: the effect of altitude.

Abstract

In this study birthweight distributions for Mexican Americans and Mexico City were compared. Sharp differences in the two distributions were nearly eliminated by controlling for altitude. The small remaining excess in low birthweight in Mexico City appears to be due to a slight overrepresentation of tertiary hospital deliveries, and possibly to a greater prevalence of pathological conditions. The results are consistent with the favorable low birthweight rate reported for Mexican Americans and illustrate the need to adjust for altitude in studies of low birthweight.