All ETDs from UAB

Advisory Committee Chair

John Waterbor

Advisory Committee Members

Walter Alarcon

Julia Gohlke

Debra Hodges

Pauline Jolly

Document Type

Dissertation

Date of Award

2018

Degree Name by School

Doctor of Philosophy (PhD) School of Public Health

Abstract

Epidemiologic studies have indicated an association between lead exposure and cancer. Although lead exposure has declined in recent decades, from removal of lead in gasoline and paint, lead exposure remains a health concern from environmental and occupational sources including aging water systems. In a retrospective cohort study, Adult Blood Lead Epidemiology and Surveillance (ABLES) records in Alabama were linked to cancer incidence data in the Alabama Statewide Cancer Registry and mortality data from the Alabama Center for Health Statistics, using a probabilistic linkage program. Blood lead level (BLL) measurements were used to categorize exposure levels. Odds ratios approximated relative risks. Logistic regression assessed dose-response across five exposure levels (highest ≥40 μg/dL) compared to baseline exposure (<5 μg/dL). Standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) were calculated using the Alabama population to estimate expected cases of “any cancer”; cancers of the bladder, brain, kidney, lung, and stomach; and expected deaths. SIRs for males in the highest exposure groups were compared with SIRs from a published study of cancer incidence in New Jersey’s ABLES cohort. Of 14,274 individuals in the Alabama ABLES cohort, those highly exposed to lead had significantly increased odds of developing cancer (OR = 2.2), kidney cancer (OR = 3.5), and lung cancer (OR= 3.2), comparing high (≥10 μg/dL) to baseline exposure. Significant trends across five exposure levels indicated dose-response. The odds of kidney cancer increased with dose but did not reach statistical significance. The ABLES cohort exhibited fewer cancer cases and fewer deaths than expected based on Alabama’s cancer incidence and overall mortality rates, suggesting a healthy worker effect. The cancer SIRs for Alabama ABLES males and New Jersey ABLES males were strikingly similar, with ~50% fewer cancer cases observed in the respective ABLES cohorts than were expected. Individuals in the Alabama ABLES cohort with elevated BLL have a statistically significant increased odds of cancer, lung cancer, and kidney cancer, compared to those minimally exposed, exhibiting dose-response across five levels of lead exposure. Similarities to the New Jersey ABLES analysis suggest that our results are reliable, and that lead is a risk factor for cancer.

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