Associations of cadmium and lead exposure with leukocyte telomere length: findings from National Health and Nutrition Examination Survey, 1999-2002.
Level 4 - case-series / case-control
Cross-sectional analysis of national survey data
PubMed 25504027 · doi:10.1093/aje/kwu293
What was done
Researchers analyzed data from a nationally representative sample of US adults participating in the National Health and Nutrition Examination Survey (NHANES, 1999–2002). They evaluated multivariable-adjusted associations between leukocyte telomere length (LTL) and concentrations of blood lead (n = 6,796), blood cadmium (n = 6,796), and urinary cadmium (n = 2,093).
What was found
Geometric mean concentrations were 1.67 µg/dL (95% CI: 1.63, 1.70) for blood lead, 0.44 µg/L (95% CI: 0.42, 0.47) for blood cadmium, and 0.28 µg/L (95% CI: 0.27, 0.30) for urine cadmium. In adjusted models, the highest compared with lowest quartiles showed -5.54% shorter LTL for blood cadmium (95% CI: -8.70, -2.37) and -4.50% shorter LTL for urine cadmium (95% CI: -8.79, -0.20), both exhibiting significant dose-response trends (P for trend < 0.05). Blood lead showed no association with LTL.
Why it matters
This study provides population-level evidence linking low-level environmental cadmium exposure to biological markers of accelerated cellular aging, pointing to a potential mechanism for cadmium-associated chronic disease risk.
Limits
The cross-sectional design cannot establish causality or the temporal sequence of exposure and telomere shortening. Biomarkers were measured at a single time point, urine cadmium was measured in a smaller subpopulation (n = 2,093), and residual confounding cannot be excluded.
Cited by
- partial Heavy metal exposure to cadmium and lead is associated with shorter telomeres in a dose-response manner.