Growth in height and weight of South African urban infants from birth to five years: The Birth to Ten Study.

The Birth To Ten (BTT) birth cohort study was designed to investigate the health and growth of children living in the Soweto-Johannesburg Metropole, South Africa. During 1990-1991, 4034 singleton births, from a total birth population of 5449 that occurred between 23 April and 8 June, 1990, were enrolled into the study. Anthropometric, socioeconomic, health, nutritional, and demographic data were collected at birth and at 3, 6, 12, 24, 48, and 60 months. Socioeconomic data relating to household commodities, maternal education, and paternal occupation were combined to create socioeconomic status (SES) groups for comparative purposes. Mean birth weights were less than American norms and demonstrated significant differences between the sexes. The percentage of low birth weight children of normal gestational age (7.1%) was similar to that of developed countries. Growth in weight exceeded that of the National Center for Health Statistics (NCHS) reference during the first 6 months and then fell to -0.43 Z-scores by 4 years. Height growth was consistently less than the NCHS reference and the prevalence of stunting and wasting increased to 22.4% and 6.8%, respectively, by 2 years. Catch-up occurred between 4 and 5 years resulting in a reduction in the prevalence of stunting and wasting to 5.4% and 0.8%, respectively, at 5 years. SES differences were apparent throughout the time period but only reached significance in height and weight after 4 years of age. Am. J. Hum. Biol. 10:495-504, 1998. © 1998 Wiley-Liss, Inc.