Who is breast-feeding? Implications of associated social and biomedical variables for research on the consequences of method of infant feeding.

The objective of this paper is to identify social and biomedical variables that influence the selection of methods of infant feeding in the United States and to provide guidelines for the choice of control variables in the design and interpretation of studies that examine the influence of breast-feeding on infant and child health. Data were drawn from a national household survey, the Child Health Supplement of the 1981 Health Interview Survey conducted by the National Center for Health Statistics. Relationships between demographic, socioeconomic, and health variables were studied for the total sample of children under age 5 y as well as for black and white women separately. The data provide evidence for the importance of both social and health variables as selection factors for breast-feeding in the United States.