Year of Publication

2012

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Medicine

Department

Nutritional Sciences

First Advisor

Dr. Lisa Gaetke

Abstract

Diabetes and cardiovascular disease are leading causes of death and disability in the United States. These chronic diseases are clinical sequelae of metabolic syndrome (MetS), a condition that affects approximately one-third (1/3) of American adults. Metabolic syndrome occurs in response to environmental and genetic influences, among them food intake, a sedentary lifestyle, BMI, advancing age, and exposure to persistent organic pollutants (POPs). POPs are known to cause endocrine disruption and PCBs cause oxidative stress, disrupt endothelial cell integrity, and promote atherosclerosis. Nutrition plays a significant role in the prevention and management of these chronic diseases and has been shown to modulate the toxicity of PCBs. Serum carotenoid (SC) concentrations are the best biomarker indicative of fruit and vegetable intake and an improved nutritional status.

The purpose of this study was to investigate the relationship between serum carotenoid concentrations, serum concentrations of PCBs, and the probability of developing metabolic syndrome. The National Health and Nutrition Examination Survey (NHANES) is a program of the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention (CDC), that utilizes a cross-sectional sample survey design to collect, maintain, and disseminate the health and nutrition data of persons residing in the United States. Carotenoids and PCBs share similar biological pathways due in part to lipophilicity. Both concentrate to lipids in blood, are stored primarily in adipose tissue, and may competitively bind nuclear receptors.

A statistical interaction was sought between the two variables for their combined effect on the probability of metabolic syndrome. An increase in probability was observed in the first exposure quartile for many PCBs, individually and pooled, suggestive of a low dose endocrine effect. Statistical modeling consistently showed strong decreasing trends in the probability of metabolic syndrome with higher concentrations of serum carotenoids in the 3rd and 4th PCB exposure quartiles. These data suggest a protective effect of serum carotenoids, and therefore of fruit and vegetable intake, despite higher serum levels of PCBs, in the probability of developing metabolic syndrome.

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