This project uses data from the Third National Health and Nutrition Examination Survey (NHANES III, 1988-84), linked to birth certificates for sample children ages 2-83 mo (coordinated by Dr. Overpeck through an interagency agreement with NCHS/CDC) to explore the health consequences of intrauterine growth. Completed analyses in this year focused on the effects of perinatal factors on early childhood caries (ECC). With improved survival of infants born very preterm, questions have arisen as to whether there are consequences for childhood dental development, particularly whether preterm delivery is associated with an increased risk of ECC. Information on demographic characteristics (race/ethnicity, family income), nutrition (infant feeding, childhood diet, supplements), exposure to fluoridated water, and caries status was extracted for 3,273 children, ages 3-5 years, from the Third National Health and Nutrition Examination Survey (1988-1994). These were linked to birth certificates to acquire birth weight and define degree of prematurity (very preterm <33 wk, preterm 33-36 wk, term 37+ wk); 2.2% were born very preterm, and 7.2% preterm. The main outcome variable was ECC, defined as no caries, moderate (1-7 teeth affected) and severe (8+ teeth affected). The major environmental factor related to caries, the probability of exposure to fluoridated water (public sources) at levels consistent with a protective effect (> 0.6 ppm), was estimated based on region and residential county size. As expected, exposure to fluoridated water was associated with a decrease in number of primary teeth affected with caries (-1.3 teeth affected/10% increase in probability of exposure, p<.001). Adjusting for fluoridated water exposure and other confounding, children born preterm had only a modest increased risk of ECC. However, children born very preterm had a twofold increased risk of moderate ECC (AOR=2.04, 95% CI=0.73-5.67), and a dramatically increased risk of severe ECC (AOR=11.94, 95% CI 1.16-123.07). Thus, the primary dentition of children born very preterm may be susceptible to ECC because of disruptions in tooth enamel formation or factors associated with their postnatal intensive care.