The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. I. Background and introduction.

The Special Supplemental Food Program for Women, Infants, and Children (WIC) aims to improve the nutrition and health of low-income, nutritionally at-risk pregnant women and preschool children with supplemental food, nutrition education, and coordination of health care. Started in 1972, it recently served greater than 3.4 million persons monthly and at a cost of $1.66 billion annually. The National WIC Evaluation (NWE) consisted of four studies: The historical study estimated changes in birth outcome attributable to WIC from 1972 to 1980 in 19 states and the District of Columbia from WIC program data and vital statistics. The longitudinal study of pregnant women compared dietary intake, weight gain, anthropometry, duration of gestation, birth weight, and infant length and head circumference between a representative national sample of WIC participants and economically comparable women. The cross-sectional study of preschool children related WIC to dietary intake, anthropometry, and psychological development. The food expenditures study estimated the impact of WIC on family grocery and other food expenditures.

The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. IV. Study methodology and sample characteristics in the longitudinal study of pregnant women, the study of children, and the food expenditures study.

The longitudinal study of pregnant women enrolled a national probability sample of 5,205 women first certified for WIC and 1,358 comparable low-income pregnant women in 174 WIC clinics located in 58 areas in the contiguous 48 states and in 55 prenatal clinics without WIC programs in counties with low program coverage. The women completed 24-h dietary recalls, histories of food expenditures, health care utilization, health and sociodemographic status, and anthropometric assessment. At late-pregnancy follow-up 3,967 WIC and 1043 control women were interviewed and 853 WIC and 762 control women completed 1-wk food expenditure diaries. Birth outcome was abstracted (from hospital records) for 3,863 WIC and 1058 control women. Anthropometry, dietary intake, health, and use of health services were related to WIC among 2,619 random low-income preschoolers. Psychological development was assessed in 526 children aged 4 and 5 y. Control women had higher income, education, and employment status; therefore, WIC program benefits probably were underestimated.

The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. V. Longitudinal study of pregnant women.

The major associations with the Special Supplemental Food Program for Women, Infants, and Children (WIC) in pregnancy were increased intake of protein, iron, calcium, and vitamin C (four of five targeted nutrients) and of energy, magnesium, phosphorus, thiamin, riboflavin, niacin, vitamin B-6, and vitamin B-12; reversal of low weight gain in early pregnancy; smaller fat stores in late pregnancy; reduced frequency of premature rupture of the uterine membranes; larger infant head circumference with no effect on birth weight and length; increased birth weight and head circumference with better program quality; and lower fetal mortality of appreciable but not significant magnitude. Incremental energy intake was comparable to that in most small-scale supplementation trials. There was no evidence of effects on frequency of prenatal care, use of alcohol or tobacco, the intention to breast-feed, or the rate of breast-feeding. Maternal alcohol intake was associated with depressed infant head circumference, over and above effects on birth weight and length.

The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. VI. Study of infants and children.

The major associations with the Special Supplemental Food Program for Women, Infants, and Children (WIC) in preschool children were better dietary intake associated with current WIC participation, especially for Fe, vitamin A, and vitamin C, but there were no increases in energy intake and, after infancy, no residual benefits from past WIC participation; strongest dietary effects among children who were poor, black, or in single-parent or large families (children lost to WIC were as needy as those currently enrolled); shorter stature, suggesting effective targeting (with enrollment in utero there was no parallel deficit in head circumference, which is consistent with results for newborns); better immunization and more frequent regular source of health care but no more frequent use of preventive health services; and better vocabulary with WIC participation begun in utero; better digit memory with entry into the program after the first birthday (differences that emerged only after statistical adjustment for sociodemographic factors); and more advantageous child behavior (NS).

The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. VII. Study of food expenditures.

Recalls of monthly family food expenditure, taken before and after maternal WIC benefits, were obtained from 4,219 WIC and 785 control women; 1-wk expenditure diaries (at follow-up) were obtained from 1,031 WIC and 551 control women chosen randomly. Control families had higher incomes, spent more on groceries and in restaurants, and received fewer food stamp benefits. Women probably underreported the value of WIC benefits by recall (WIC vouchers are not dollar denominated). Although control families were more affluent, there were consistent effects of children's WIC benefits on weekly family grocery expenditure by diary ($6.10, p less than 0.05) and by recall ($2.14, p less than 0.01, and $1.48, p less than 0.05). WIC benefits to infants were associated with very large (but not significant) increments in grocery spending by diary ($7.57). WIC benefits to the pregnant woman were strongly associated with larger amounts of WIC food entering the household (as were infant and child benefits) but effects on grocery spending were unclear.

Decreasing fuel-oil consumption through feedback and social commendation.

The energy crisis of the winter of 1973-74 led to severe shortages of fuel oil for home heating and a government request for voluntary conservation by the oil consumer. This experiment tested two methods of facilitating fuel-oil conservation. Home fuel-oil consumers were randomly assigned to one of three experimental groups: feedback of information on rate of oil use, feedback plus commendation for reduced consumption, or a no-treatment control. The consumption rate for the feedback plus commendation group was significantly lower than that of either the informational feedback group or the control group. The informational feedback group did not differ from the control group. The results suggest that feedback alone may not result in oil conservation, but that feedback combined with commendation can produce socially significant savings.