Mothers prolong breastfeeding of undernourished children in rural Senegal.

BACKGROUND: Breastfeeding, when prolonged beyond infancy, is a risk factor for low nutritional status in most cross-sectional samples from less developed countries. Therefore, it has been suggested that prolonged breastfeeding impairs growth. To test whether, on the contrary, breastfeeding is prolonged because the child is already undernourished, nutritional status prior to weaning was compared according to age at weaning.
METHODS: Precise dates of birth and weaning were collected weekly through continuous demographic surveillance in a rural area of Senegal. Weight and length at 9-10 months were measured during vaccination sessions (coverage: 78%) from 1989 to 1996. Eight infants weaned before 9 months were excluded, and the duration of breastfeeding of the remaining 4515 children was compared according to nutritional status at 9-10 months by survival analysis.
RESULTS: Length-for-age during infancy was associated with duration of breastfeeding: the median duration was 25.0 months for z-scores <-2, 24.1 months for z-scores -2 to -1, 23.4 months for z-scores -1 to 0 and 22.7 months for z-scores >0 (P for trend <0.0001). Weight-for-length during infancy was also associated with duration of breastfeeding (P for trend <0.0001), though the differences among groups were smaller. The relationships remained at the same significance levels after adjustment for season of birth, mother's age, parity, height, occupation and education.
CONCLUSION: Duration of breastfeeding is not determined by characteristics of the mothers only. Women prolong breastfeeding for undernourished children and reduce the duration for well-nourished children, probably because they are aware of the mortality risk following weaning.