LENGTH AND PONDERAL INDEX AT BIRTH - ASSOCIATIONS WITH MORTALITY, HOSPITALIZATIONS, DEVELOPMENT AND POSTNATAL-GROWTH IN BRAZILIAN INFANTS

Background Low birthweight infants suffer greater mortality and neonat al morbidity, grow less well in infancy and show poorer psyche-motor d evelopment. However, this simple categorization may obscure important differences in aetiology and prognosis between infants born stunted, t hin, or both. Methods In 1993, all births in Pelotas, Brazil, were enr olled into a prospective study of health and development in infancy. O f 5249 live births, 5160 had length and weight measures at birth, and were classified into tertiles of length and ponderal index. All deaths and hospitalizations were monitored, and suspected developmental dela y and attained growth at 12 months were assessed on a subsample of 136 4 infants. Logistic regression was used to control for gestational age and socioeconomic status. Results There was no association between bi rth length and ponderal index tertiles. After adjusting for gestationa l age, infants in the lower tertiles of bath length and ponderal index presented a 3.8-times higher risk of mortality from day 8 to day 365, and a 2.5-times higher risk of hospitalization compared to infants wi th greater birth lengths and/or ponderal indices. Suspected developmen tal delay was associated with length and, less strongly, with ponderal index, but there was no synergism between the two. Infants in the mid dle and upper tertiles of ponderal index at birth became thinner. Conc lusions Birth length was strongly associated with development at 12 mo nths, but only infants born both short and thin were at increased risk of mortality and hospitalizations. The combination of the two measure s provides a useful classification of the anthropometric status of the newborn.