Ami Zota, Sc.D.; Sung Kyun Park, Sc.D.
George Washington University, University of Michigan
NIEHS Grants: R00ES019881, K01ES016587
A study, supported in part by NIEHS, found an association between cadmium exposure and shorter leukocyte telomere length, a marker of cellular aging. Findings from the study also indicate that cadmium might be harmful at levels well below current safety standards set by environmental and occupational safety agencies.
Cell and animal studies have suggested that lead and cadmium induce a shortening of telomeres, which protect the ends of chromosomes. To study this type of cellular damage in people, the researchers examined leukocyte telomere length as well as blood and urine samples from more than 6,700 adults who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2002. After adjusting for potential confounders, the highest (versus lowest) quartiles of blood and urine cadmium were associated with -5.54 percent (95 percent CI: -8.70, -2.37) and -4.50 percent (95 percent CI: -8.79, -0.20) shorter leukocyte telomere lengths, respectively, with evidence of dose-response relationship (P for trend < 0.05). The difference between participants of the same chronological age with low and high cadmium exposure is equivalent to 11 years of age. No association was found between lead levels and telomere length.
Since other studies have shown an association between shorter leukocyte telomere lengths and diseases of aging — including cardiovascular disease, type 2 diabetes, dementia, and cancer — the new findings provide insight into the biological mechanisms underlying cadmium exposure and chronic disease risks.
Citation: Zota AR, Needham BL, Blackburn EH, Lin J, Park SK, Rehkopf DH, Epel ES. 2015. Associations of cadmium and lead exposure with leukocyte telomere length: findings from National Health and Nutrition Examination Survey, 1999-2002. Am J Epidemiol 181(2):127-136.