Date of Award

2016

Document Type

Open Access Dissertation

Department

Epidemiology and Biostatistics

Sub-Department

Norman J. Arnold School of Public Health

First Advisor

Swann Arp Adams

Abstract

There is evidence from earlier studies that oral contraceptive pills may be a risk factor for certain chronic diseases, including heart disease, stroke, and breast cancer. Previous studies mainly focus on the estrogen component of combined (estrogen+ progestin) oral contraceptives (COCs) due to their popularity. This focus limits our understanding of progestin-only contraceptives and its relationship to commonly occurring chronic diseases. To provide insight into alternative methods of oral contraception, this dissertation explores the relationship between progestin-only oral contraceptive (POC) pills and heart disease, stroke, and breast cancer. We hypothesize that women using POCs are less likely to have certain chronic diseases compared to women using COCs.

We conducted a retrospective cohort study using Medicaid data for 2000-2013 to (1) examine trends in OC medication use over time, (2) determine the association between the type of OC use and breast cancer mortality, and (3) compare estrogen+ progestin formulations with progestin-only regimens to understand the association of OC types and cardiovascular disease. We found an increasing trend of POC and POC+COC use in the Medicaid population from 2000 to 2013, which could reflect increased knowledge of POCs. However, COCs are still prescribed much more frequently than any other contraceptive method.

In further investigations, we found evidence that women using POCs had a significantly reduced risk of breast cancer mortality whereas women using COCs had an increased risk. Similarly, POCs decreased the risk of heart disease compared to COC use. Conversely, the relationship between POCs and stroke was more abstruse. All analyses were stratified by race to explore differences in oral contraceptive use among African American and European American women in the South Carolina Medicaid registry. We aimed to study a population that is typically under-represented in the scientific literature.

The findings of this study suggest that there may be beneficial effects of using POCs in lieu of COCs to reduce estrogen-related complications of oral contraceptives. Additional studies are required to provide conclusive evidence.

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