A LONGITUDINAL-STUDY OF CHRONIC LEAD-EXPOSURE AND PHYSICAL GROWTH IN BOSTON CHILDREN

We investigated the cross-sectional and longitudinal relationships bet ween chronic exposure to lead and physical growth among a cohort of ch ildren reassessed 13 years after initial examination. We measured weig ht, height, and dentin lead levels of 270 children in 1975-78. In 1989 -1390 we reexamined 79 of these children for measurement of weight, he ight, and bone Lead levels by means of irt vivo K X-ray fluorescence. To avoid potential confounding by race and chelation history, analysis was restricted to white subjects without a history of lead chelation therapy. A total of 236 subjects provided complete information for the study of cross-sectional relationship between dentin lead levels and physical growth: 58 subjects for the study of longitudinal relationshi p between dentin lead levels and changes in physical growth and 54 sub jects for che study of longitudinal relationship between bone lead lev els and changes in physical growth. Dentin lead levels averaged 14.9 m u g/g; tibia and patella lead levels averaged 1.2 and 5.0 mu g/g, resp ectively. With control for potential confounders including age, sex, b aseline body size, and mother's socioeconomic status, log(10) dentin l ead level was positively associated with body mass index as of 1375-19 78 (beta = 1.02, p = 0.03) and increase in body mass index between 197 5-78 and 1989-90 (beta = 2.65, p = 0.03). Bone lead levels were not si gnificantly associated with physical growth. This is the first study r elating chronic lead exposure to body mass index. The results suggest that chronic lead exposure in childhood may result in obesity that per sists into adulthood.