The association between caries and childhood lead exposure

Epidemiologic studies suggest an association between lead exposure and cari es. Our objective was to establish whether children with a higher lead expo sure as toddlers had more caries at school age than children with a lower l ead exposure. We used a retrospective cohort design. A sample of children w ho attended second and fifth grades in the Rochester, New York, public scho ols during the 1995-1996 and 1996-1997 school years were examined for carie s through a dental screening program. For each child we assessed the number of decayed, missing, or filled surfaces on permanent teeth (DMFS), and the number of decayed or filled surfaces on deciduous teeth (dfs); the number of surfaces at risk (SAR) was also recorded. Lead exposure was defined as t he mean of all blood lead levels collected between 18 and 37 months of age by fingerstick [provided the blood lead level was less than or equal to 0.4 8 mu mol/L (less than or equal to 10 mug/dL)] or venipuncture. A total of 2 48 children (197 second graders and 51 fifth graders) were examined for car ies and had a record of blood lead levels to define lead exposure. The mean dfs was 3.4 (range 0-29); the mean DMFS was 0.5 (range 0-8). Logistic regr ession was used to examine the association between the proportion of childr en with DMFS greater than or equal to 1, and the proportion with dfs greate r than or equal to 1, and lead exposure [< 0.48 <mu>mol/L vs. greater than or equal to 0.48 mu mol/L (< 10 <mu>g/dL vs. greater than or equal to 10 mu g/dL)] while controlling for SAR, age at examination, and grade in school. For DMFS, the adjusted odds ratio was 0.95 [95% confidence interval (CI), 0 .43-2.09; p = 0.89); for dfs, the odds ratio was 1.77 (95% CI, 0.97-3.24; p = 0.07). This study did not demonstrate that lead exposure > 10 mug/dL as a toddler was a strong predictor of caries among school-age children. Howev er, the results should be interpreted cautiously because of limitations in the assessment of lead exposure and limited statistical power.