The primary objectives of this retrospective cohort study are to assess the impact of early protein-energy malnutrition (PEM) on the permanent dentition, specifically with respect to: 1) dental caries, 2) enamel hypoplasia, 3) tooth eruption timing, and 4) salivary function. The proposed investigation will seek to assess clear dose-response and temporal relationships between early childhood PEM (ages birth-5 years old) and these oral outcomes at ages 12-18 years. An explanatory model of enamel hypoplasia, salivary gland hypofunction, tooth eruption timing, and social and behavioral risk factors as possible mechanisms for caries following PEM exposure will be examined. The few existing published human studies of PEM and oral outcomes were typically of cross-sectional design, with limited control for confounding variables, and almost exclusively focused on the primary dentition. Until now, there has been no high quality data base of past PEM exposure with a sufficient lag period of 10 years or more to allow the study of early childhood malnutrition effects on the permanent dentition. This study will capitalize on a 'natural experiment situation' that has occurred in Haiti, i.e., a database of serial weightings of children in their first 5 years of life, who had experienced the full range of PEM, and will maximize the time since exposure for disease determination. PEM exposure will be assessed using weights included in an ongoing Haitian Health Foundation database maintained since 1988 on over 16,000 children. The completion of this natural experiment only requires the collection of the oral health data from a randomly selected sub-group of these 16,000 children, stratified by nutrition status according to the severity and chronicity of their exposure to PEM. A random sample of 12-18 year old children frequency matched for age and gender will be recruited from each PEM stratum, for a total sample of 1,250 children. The investigation will consist of a four-month-long field dental examination, saliva collection and interview survey by a calibrated team of U.S. and Haitian trained dentists and epidemiologists. The primary analyses will consist of regression models that will assess the associations between the four oral outcomes and PEM levels and social/behavioral factors, as well as determining age-specific critical PEM exposure(s). The findings of this study will provide the first scientific evidence regarding the potential effect of early childhood PEM on the complete permanent dentition based on a retrospective longitudinal cohort study. Given the universality of PEM pathophysiology, this study's findings will be generalizable to subsets of U.S. children having oral health disparities.
