Introduction: Six of 14 prior studies reported significant associations between cadmium (Cd) and type 2 diabetes mellitus (T2DM).
Materials and Methods: In a Superfund Cleanup community, Phase II screening included physical examination and laboratory tests. Participants were African Americans aged ≥19 years to ≦89 years. Multiple logistic regression was used.
Results: Of 873 subjects environmentally exposed, 109 T2DM individuals who lived in the community for an average of 21.0 years, and 766 non-T2DM individuals resident in the study community for 19.0 years. Most T2DM individuals (70.3%) were ≥50 years old (p<0.00001). Blood Cd levels were significantly higher among T2DM subjects (p<0.006). T2DM status was regressed on age ≥50 years, Cd, other metals, decades of residence in smelter community, gender, abnormal GGT, and smoking. T2DM predictors were age ≥ 50 years (OR = 3.10; 95% CI: 1.91-5.02, p<0.0001), Cd level (OR = 1.85; 95% CI: 1.14 - 2.99, p < 0.01), and BMI (OR=1.07; CI: 1.04-1.09).
Discussion: Cd exposure is associated with T2DM in an EPA Superfund community, controlling for covariate effects. Comparing our findings with 14 prior Cd and T2DM studies shows that T2DM rates less than 10% were not sufficiently powered, unless OR ≥ 3.0 (See Figure). Findings suggest that Cd is associated with T2DM, and studies failing to show a significant effect may have a Type II error, and not an indication of no association.
B.B. Little: None. R.F. Reilly: None. B. Walsh: None.