Psychosocial Predictors of Being an Underweight Infant Differ by Racial Group: A Prospective Study of Louisiana WIC Program Participants

Objectives: In order to prospectively identify psychosocial predictors of infants being underweight, we followed 3,302 low-income infants. These infants received well-baby care in health departments and were enrolled in the Women, Infants, and Children (WIC) Supplemental Food Program from the newborn period to 12 months of age. Methods: We linked risk factor data collected from newborn medical history records to anthropometric data from a WIC database. The unadjusted relative risk of being underweight at 12 months of age, defined as weight for recumbent length below the 5th percentile, according to current Centers for Disease Control and Prevention growth charts, for each group was calculated for the study population and for black and white racial groups. Using logistic regression, we calculated odds ratios measuring the effect of the newborn risk factors on underweight status at 12 months of age. Results: There were no psychosocial risk factors that were significantly associated with being underweight simultaneously in both racial groups. Among black infants, those whose mothers had an eighth grade education or lower were at greater risk of being underweight at 12 months of age (OR=3.7, CI=1.5–4.8), as were those whose mothers were married (OR=2.7, CI=1.5–4.8). Among white infants, those whose mothers initiated prenatal care in the third trimester were significantly more likely to have underweight infants at 12 months of age (OR=4.5, CI=1.6–12.4). Conclusions: Predictors of being underweight at 12 months of age in a low-income population differ by racial group. Further research of public health interventions targeting families of infants with the significant psychosocial risk factors is needed.