Association of Caries and Water Lead Concentrations in Puerto Rico

Objective: Long-term exposure to lead can result in adverse medical outcomes, with minority individuals and communities often disproportionately affected. Limited animal and human studies support lead as a risk factor for dental caries, though the exposure timing, dosage and actions are still somewhat speculative. The goal of this study is to determine whether there is an association between long-term lead exposure, using school drinking water as a proxy for exposure, and the dental caries prevalence of 12-year-old children in Puerto Rico (PR). No prior studies have investigated this association in PR.

Methods: A database consisting of a probabilistic sample of 1435 12-year-old children, representing over 70,000 in PR provided the gender, socioeconomic status and DMFS data. Lead concentrations in school water, as reported by the PR water authorities, were assigned to each child in the school serviced by each water plant. Descriptive statistics and linear regression were performed using SPSS-Version-12.0.

Results: Overall, 10% of the water filtration plants in PR reported water lead levels that exceeded 10ppb while some plants reported lead levels in excess of 52ppb (mean 5.7); maximum permissible concentration of lead in water by EPA is 15ppb. DMFS scores for the school children ranged from 0-42 (mean 6.3). A linear regression model, controlling for gender and socioeconomic level, demonstrated a statistically significant relationship (p=.005) between water lead levels dichotomized above and below 10ppb and DMFS scores.

Conclusions: Reported lead levels in drinking water raise public health concerns. An association between lead levels above 10ppb in water and DMFS scores was observed. Further research studies are needed to investigate additional ecological factors such as fluoride levels and other metal-metal interactions in school water and caries.

This project was supported by Grant 5-R25-RR17589 from the National Center for Research Resources(NCRR), a component of the National Institutes of Health(NIH).