Does low birthweight influence the nutritional status of children at school age? A cohort study in northeast Brazil

Birthweight is recognized to be a determinant of a full term infant's early growth pattern; however, few studies have explored whether this effect is sustained into school age, especially in developing countries. We have used a cohort study from North East Brazil to investigate factors determining the anthropometric status of eight-year-old children born at full-term with low or appropriate weight. A cohort of 375 full-term infants was recruited at birth in six maternity hospitals between 1993 and 1994, in a poor region of the interior of the State of Pernambuco. At the age of 8 years, 86 born with low birthweight and 127 with appropriate birthweight were traced. Multivariable linear regression analyses were used to identify the net effect of socioeconomic conditions, maternal nutritional status and child factors on weight-for-age and height-for-age. An enter approach was used to estimate the contribution of different factors on child anthropometry. Birthweight had little influence on child nutritional status at school age. Maternal BMI and height together were the biggest contributors to variation in child weight-for-age (12.3%) and height-for-age (13.2%), followed by family socioeconomic conditions. Maternal height as a proxy of maternal constraint was the single factor that best explained the variation in both indices (6.2% for weight-for-age and 11.1% for height-for-age). Haemoglobin level measured at eight years made a small but significant contribution to variation in height-for-age (5.6%) and weight for age (1.4%). Maternal nutritional status, reflecting genetic inheritance and the poor socioeconomic conditions of this population, was the most important determinant of the nutritional status of children at school age, rather than birthweight.