Environmental cadmium exposure and pediatric dental caries

Objectives: To examine the relationship between environmental cadmium exposure and dental caries in children. Methods: Firstly, we analyzed cross-sectional data, including urine cadmium concentrations and counts of decayed or filled tooth surfaces, on approximately 2000 children from the third National Health and Nutrition Examination Survey (NHANES III). We used logistic and zero-inflated negative binomial (ZINB) regression to estimate the association between urine cadmium concentrations and caries experience, adjusting these analyses for potential confounders including environmental tobacco smoke (ETS). Secondly, we undertook a pilot study to test the hypothesis that environmental cadmium exposure may disrupt salivary gland function. We measured concentrations of cadmium, total protein and α-amylase activity in saliva of 37 children living near a site contaminated by mining waste. Results: In the NHANES III sample, an interquartile range (IQR) increase in creatinine-corrected cadmium concentration (0.21 µg/g creatinine) corresponded to a 16% increase in the odds of having experienced caries in deciduous teeth (prevalence odds ratio (OR) = 1.16; 95% CI: 0.96-1.40). This association was statistically significant in children with low ETS exposure (prevalence OR = 1.30; 95% CI: 1.01-1.67). ZINB regression analyses indicated that, among children with any deciduous caries, an IQR increase in cadmium was associated with 17% increase in the number of decayed or filled surfaces. We observed no association between cadmium and caries experience in permanent teeth. Results of the cross-sectional pilot study showed that for a 1 ng/mL increase in salivary cadmium, there was a 5% reduction in total protein concentrations. No statistically significant association was observed between salivary cadmium and α-amylase activity. Conclusions: Environmental cadmium exposure may be associated with increased risk of dental caries in deciduous teeth of children. Acknowledgment: NHANES III analyses presented here have been submitted for publication in Environmental Health Perspectives. Funding: Faculty Seed Grant, Harvard University Centre for the Environment.