The effects of the WIC program on the growth of infants.

The Special Supplemental Food Program for Women, Infants and Children (WIC) provides food supplements and nutrition counseling to pregnant and lactating women and children up to age 5 who are at nutritional risk. The purpose of this study was to determine the effects of the program on the growth of infants. Retrospective longitudinal anthropometric data were obtained on 906 WIC and 1001 non-WIC infants from birth to 18 months of age. A new methodology was developed that addressed two factors in longitudinal studies frequently confounded with program impact: 1) regression to the mean and 2) expected growth. Regression analyses indicated that children who were on WIC between 6 and 18 months of age were growing at greater than expected rates. The most persistent program effect was at 6 months of age, after the children had been on the program for an average of 4 months. The study indicated that data routinely collected by the program can be used for evaluation purposes.