Urinary Cadmium, Impaired Fasting Glucose, and Diabetes in the NHANES III

Abstract

OBJECTIVE—Increasing rates of type 2 diabetes worldwide suggest that diabetes may be caused by environmental toxins. Cadmium is a widespread environmental pollutant that accumulates in the pancreas and exerts diabetogenic effects in animals. To test the hypothesis that exposure to cadmium is associated with impaired fasting glucose and type 2 diabetes, we examined the associations between urinary cadmium and the prevalence of impaired fasting glucose (prediabetes) and diabetes in the Third National Health and Nutrition Examination Survey (NHANES III). RESEARCH DESIGN AND METHODS—We analyzed data on 8,722 adults ≥40 years of age from the NHANES III (1988–1994), a cross-sectional health survey of a nationally representative sample of the noninstitutionalized civilian U.S. population. We studied urinary levels of cadmium (adjusted for urine creatinine) in relation to the prevalence of impaired fasting glucose and diabetes, using the criteria of the American Diabetes Association. RESULTS—After adjustment for age, ethnicity, sex, and BMI, the odds of impaired fasting glucose and diabetes increased dose-dependently with elevations in urinary cadmium from 0–0.99 to 1.00–1.99 and ≥2 μg/g creatinine (impaired fasting glucose, odds ratio [OR] 1.48, 95% CI 1.21–1.82 and OR 2.05, 95% CI 1.42–2.95; diabetes, OR 1.24, 95% CI 1.06–1.45 and OR 1.45, 95% CI 1.07–1.97). CONCLUSIONS—In this large cross-sectional study, urinary cadmium levels are significantly and dose-dependently associated with both impaired fasting glucose and diabetes. These findings, which require confirmation in prospective studies, suggest that cadmium may cause prediabetes and diabetes in humans.