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ORCID

https://orcid.org/0000-0003-4347-281X

Document Type

Open Access Thesis

Degree Program

Public Health

Degree Type

Master of Science (M.S.)

Year Degree Awarded

2020

Month Degree Awarded

May

Abstract

Phthalates are industrial chemicals added to plastics found in products such as children’s toys, cosmetics, and household items, and some laboratory studies suggest phthalates may increase levels of inflammation. Chronic inflammation is associated with many chronic health conditions, such as diabetes and rheumatoid arthritis. Although research is limited, recent studies suggest a strong positive relationship between mono-butyl phthalate (MBP), mono-isobutyl phthalate (MiBP), and monocarboxynonyl phthalate (MCNP) and c-reactive protein (CRP), as well as monoethyl phthalate (MEP) and mono-3-carboxypropyl phthalate (MCPP) and interleukin-6 (IL-6). Additionally, this relationship has not been examined among postmenopausal women, a population that is at higher risk of developing chronic health conditions. Our aim was to examine the association between urinary phthalate biomarkers and inflammation biomarkers among postmenopausal women using baseline data from a subset of participants of the Women’s Health Initiative (WHI) (n=443). Phthalate exposure was assessed using phthalate biomarkers (i.e. phthalate metabolites or their molar sum) from urine samples collected at WHI clinical centers from 1993-1998. We measured 13 phthalate metabolites: MEP, MBP, mono-hydroxybutyl phthalate (MHBP), MiBP, mono-hydroxyisobutyl phthalate (MHiBP), monobenzyl phthalate (MBzP), MCPP, mono (2-ethylhexyl) phthalate (MEHP), mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP), mono (2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-carboxyoctyl phthalate (MCOP), and MCNP. Serum and plasma inflammatory biomarker levels (i.e. CRP, IL-6) were measured in separate WHI ancillary studies, using blood samples collected at baseline. We used multivariable linear regression to analyze associations between each phthalate biomarker and inflammation biomarker, adjusting for important covariates. Phthalate biomarkers MCNP (Model 1: b = 0.523; Model 2: b = 0.362) and MCOP (Model 1: b = 0.384; Model 2: b = 0.240) were positively associated with CRP. Additionally, MCNP (Model 1: b = 0.369; Model 2: b = 0.181) was positively associated with IL-6. Statistically significant associations were not observed among the remaining phthalate biomarkers. Our findings suggest that certain phthalates may be related to increasing levels of inflammation.

First Advisor

Katherine Reeves

Second Advisor

Susan Hankinson

Included in

Epidemiology Commons

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