MATERNAL SMOKING DURING LACTATION - RELATION TO GROWTH DURING THE FIRST YEAR OF LIFE IN A DUTCH BIRTH COHORT

A recent article by Little et al, (Am J Epidemiol 1994;140:544-54) rep orted that infants in Seattle, Washington, who were breastfed by mothe rs who smoked gained more weight than either infants who were breastfe d by mothers who did not smoke or infants who were bottle-fed by mothe rs who smoked. In this study, the authors aimed to verify this result with the use of data from the Social Medical Survey of Children Attend ing Child Health Clinics (SMOCC) cohort, a nationally representative c ohort of 2,151 children born in the Netherlands in 1988-1989. During t he first year of life, data on type of milk feeding, weight, length, a nd head circumference were collected at 1, 2, 3, 6, 9, and 12 months o f age. Infants of smokers who were mainly breastfed in the first 3 mon ths of life (n = 117) were compared with similarly breastfed infants o f nonsmokers (n = 572), with infants of smokers who had been mainly bo ttle-fed (n = 270), and with infants of nonsmokers who had been mainly bottle-fed (n = 535), The authors failed to observe any additional in crease in body mass, length, or head circumference in infants of breas tfeeding smokers compared with infants of the three other groups, When the authors used all of their data to study growth with a multivariat e longitudinal regression model (general estimating equations (GEE) mo del), the data showed clearly reduced growth in breastfed children (li mited to the period after the second month of life) and some ''catch-u p'' growth in body mass and head circumference in children with intrau terine exposure to tobacco.