Cross-sectional Associations between Exposure to Persistent Organic Pollutants and Leukocyte Telomere Length among U.S. Adults in NHANES, 2001-2002.

ABSTRACT:

Background

Exposure to persistent organic pollutants (POPs) such as dioxins, furans, and polychlorinated biphenyls (PCBs) may influence leukocyte telomere length (LTL), a biomarker associated with chronic disease. In vitro research suggests dioxins may bind to the aryl hydrocarbon receptor (AhR) and induce telomerase activity, which elongates LTL. However, few epidemiologic studies have investigated associations between POPs and LTL.

Objectives

We examined the association between 18 PCBs, 7 dioxins, and 9 furans and LTL among 1,330 U.S. adults from NHANES 2001-2002.

Methods

We created three summed POP metrics based on toxic equivalency factor (TEF), a potency measure including affinity for the AhR: a) non-dioxin-like PCBs (composed of 10 non-dioxin-like PCBs; no AhR affinity and no TEF); b) non-ortho PCBs (composed of 2 non-ortho-substituted PCBs with high TEFs); and c) toxic equivalency (TEQ) (composed of 7 dioxins, 9 furans, 2 non-ortho-substituted PCBs, and 6 mono-ortho-substituted PCBs; weighted by TEF). We tested the association between each metric and LTL using linear regression, adjusting for demographics, blood cell count and distribution, and another metric with a different TEF (i.e., non-ortho PCBs and TEQ adjusted for non-dioxin-like PCBs; non-dioxin-like PCBs adjusted for non-ortho PCBs).

Results

In adjusted models, each doubling of serum concentrations of non-ortho PCBs and TEQ was associated with 3.74% (95% CI: 2.10, 5.40) and 5.29% (95% CI: 1.66, 9.05) longer LTLs, respectively. Compared with the lowest quartile, the highest quartile of exposure was associated with 9.16% (95% CI: 2.96, 15.73) and 7.84% (95% CI: -0.53, 16.92) longer LTLs, respectively. Non-dioxin-like PCBs were not associated with LTL.

Conclusions

POPs with high TEFs and AhR affinity were associated with longer LTL. Because many dioxin-associated cancers are also associated with longer LTL, these results may provide insight into the mechanisms underlying PCB- and dioxin-related carcinogenesis.

Citation

Mitro SD, Birnbaum LS, Needham BL, Zota AR. 2016. Cross-sectional associations between exposure to persistent organic pollutants and leukocyte telomere length among U.S. adults in NHANES, 2001-2002. Environ Health Perspect 124:651-658;?http://dx.doi.org/10.1289/ehp.1510187.

SUBMITTER: Mitro SD 

PROVIDER: S-EPMC4858394 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature