Length and ponderal index at birth: associations with mortality, hospitalizations, development and post-natal growth in Brazilian infants

• Published in: International journal of epidemiology Vol. 27; no. 2; pp. 242 - 247
• Main Authors: Morris, Saul S, Victoria, Cesar G, Barros, Fernando C, Halpern, Ricardo, Menezes, Ana MB, César, Juraci A, Horta, Bernardo L, Tomasi, Elaine
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.04.1998; Oxford Publishing Limited (England)
• Subjects: Adult; Analysis. Health state; Anthropometry; Biological and medical sciences; Birth Weight; body length; Brazil; Brazil - epidemiology; Child Development; Cohort Studies; Epidemiology; Female; Follow-Up Studies; General aspects; Gestational Age; Growth; hospitalization; Hospitalization - statistics & numerical data; Humans; Infant Mortality; Infant, Newborn; intrauterine growth retardation; Male; Medical sciences; ponderal index; Population; Prospective Studies; Public health. Hygiene; Public health. Hygiene-occupational medicine; Risk Factors; Social Class; Tropical medicine; South America; Brazil; America; Biometrics; Human; Birth height; Prognosis; Mortality; Prediction; Infant; Hospitalization; Postnatal development; Epidemiology; Cohort study; Risk factor; Birth weight; Public health; Measurement; South America; Americas; Prospective Studies; Age Factors; Growth; Anthropometry; Cohort Analysis; Youth; Biology; Research Methodology; Latin America; Studies; Infant Mortality > determinants; Population Characteristics; Brazil; Population; Research Report; Child Development; Developing Countries; Demographic Factors; Population Dynamics
• ISSN: 0300-5771; 1464-3685; 1464-3685
• DOI: 10.1093/ije/27.2.242

Background Low birthweight infants suffer greater mortality and neonatal morbidity, grow less well in infancy and show poorer psycho-motor development. However, this simple categorization may obscure important differences in aetiology and prognosis between infants born stunted, thin, or both. Methods In 1993, all births in Pelotas, Brazil, were enrolled into a prospective study of health and development in infancy. Of 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 delay and attained growth at 12 months were assessed on a subsample of 1364 infants. Logistic regression was used to control for gestational age and socioeconomic status. Results There was no association between birth length and ponderal index tertiles. After adjusting for gestational age, infants in the lower tertiles of both 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 with greater birth lengths and/or ponderal indices. Suspected developmental delay was associated with length and, less strongly, with ponderal index, but there was no synergism between the two. Infants in the middle and upper tertiles of ponderal index at birth became thinner. Conclusions Birth length was strongly associated with development at 12 months, but only infants born both short and thin were at increased risk of mortality and hospitalizations. The combination of the two measures provides a useful classification of the anthropometric status of the newborn.