Document Type

Open Access Thesis

Embargo Period

12-8-2015

Degree Program

Public Health

Degree Type

Master of Science (M.S.)

Year Degree Awarded

2015

Month Degree Awarded

May

Advisor Name

Katherine

Advisor Last Name

Reeves

Co-advisor Name

Susan

Co-advisor Last Name

Sturgeon

Abstract

Four in ten people in the US will be diagnosed with cancer during their lifetime. Environmental exposures are important determinants of cancer risk, causing as many as 19% of cancers worldwide. Phthalates are a group of chemicals used to increase the flexibility of plastics and vinyl in household materials such as food packaging, plastic toys, wood finishes and adhesives. Some phthalates may act as endocrine disruptors with hypothesized links to endometriosis, breast cancer, and reproductive outcomes. However, no research yet exists on phthalate exposure and all-cancer mortality. We investigated the relationship between seven urinary phthalate metabolites among 5,205 adults in National Health and Nutrition Examination Survey (NHANES), from 1999 to 2006 with mortality data through 2011. Urinary phthalate metabolites were measured in spot urine samples using HPLC-MS/MS and HPLC-ESI-MS/MS. Cox proportional hazard regressions were conducted to calculate hazard ratios and 95 percent confidence intervals for all-cancer mortality, stratified by gender. Mean creatinine adjusted metabolite concentrations ranged from 0.03 – 3.86 ug/mg in males and 0.07 – 4.37 ug/mg in females. Age-adjusted and multivariate Cox proportional hazard models did not yield statistically significant results for any metabolites. Hazard ratios in the multivariate model for continuous, creatinine adjusted, log transformed metabolite concentrations, ranged from 0.90 to 1.27 in men and 0.86 to 1.07 in women. There was no evidence for a dose-response relationship in the quartile analyses, with p-values for trend above 0.12. This research contributes to the limited cancer literature on phthalate exposure that helps direct future regulations on plasticizers in consumer products.

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