Association of Environmental Cadmium Exposure with Pediatric Dental Caries
Arora, Manish, Weuve, Jennifer, Schwartz, Joel, Wright, Robert O., Environmental Health Perspectives
BACKGROUND: Although animal experiments have shown that cadmium exposure results in severe dental caries, limited epidemiologic data are available on this issue.
OBJECTIVES: We aimed to examine the relationship between environmental cadmium exposure and dental caries in children 6-12 years of age.
METHODS: We analyzed cross-sectional data, including urine cadmium concentrations and counts of decayed or filled tooth surfaces, from the Third National Health and Nutrition Examination Survey. 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).
RESULTS: Urine cadmium concentrations ranged from 0.01 to 3.38 ng/mL. Approximately 56% of children had experienced caries in their deciduous teeth, and almost 30% had been affected by caries in their permanent dentition. An interquartile range (IQR) increase in creatinine-corrected cadmium concentrations (0.21 [mu]g/g creatinine) corresponded to a 16% increase in the odds of having experienced caries in deciduous teeth [prevalence odds ratio (OR) = 1.16; 95% confidence interval (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). The results from the ZINB regression indicated that, among children with any caries history in their deciduous teeth, 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.
CONCLUSIONS: Environmental cadmium exposure may be associated with increased risk of dental caries in deciduous teeth of children.
KEY WORDS: children, dental caries, environmental tobacco smoke, NHANES III, urine cadmium. Environ Health Perspect 116:821-825 (2008). doi:10.1289/ehp. 10947 available via http://dx.doi.org/[Online 6 February 2008]
Dental caries is the most common chronic childhood disease in the United States (U.S. Department of Health and Human Services 2000). The prevalence of dental caries exceeds 50% in 5- to 9-year-old U.S. children and increases to 78% in those 17 years of age, making this disease more common than asthma and hay fever (U.S. Department of Health and Human Services 2000). Dental caries has been associated with numerous adverse effects on children's health including pain, restricted dietary intake, impaired growth, and reduced body weight [reviewed by Shieham (2006)]. Children living below the poverty line have more severe dental caries, and many remain untreated because of low dental health insurance coverage (U.S. Department of Health and Human Services 2000). An increasing body of evidence supports the role of environmental factors in the etiology of dental caries. Exposure to lead and environmental tobacco smoke (ETS), which has high concentrations of cadmium, has been linked with an increased risk of dental caries in children (Aligne et al. 2003; Gemmel et al. 2002; Moss et al. 1999). These studies consistently reported positive associations between environmental exposures and caries in deciduous teeth (baby teeth) but not in permanent teeth (Aligne et al. 2003; Gemmel et al. 2002; Youravong et al. 2006), indicating that children's deciduous dentition may be particularly susceptible to environmental toxicants.
An estimated 2.3% of Americans have elevated urine cadmium concentrations, a bio-marker of cumulative cadmium exposure (Paschal et al. 2000). ETS, a known risk factor for dental caries in children, accounts for approximately 20% of urine cadmium levels in U.S. children (Mannino et al. 2002). Other sources of cadmium include emissions from mining, smelting, fuel combustion, phosphate fertilizer use, sewage sludge application, disposal of metal wastes, and industrial uses of cadmium in manufacturing of batteries, pigments, stabilizers, and alloys [Agency for Toxic Substances and Disease Registry (ATSDR) 1999]. …