Dietary omega-3 fatty acids and risk of incident sporadic colorectal adenomas: Analysis of a case-control study Open Access

Tolbert, Ethan Wade (2009)

Permanent URL: https://etd.library.emory.edu/concern/etds/4t64gn629?locale=en
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Abstract

Background: Omega-3 fatty acids may reduce colorectal carcinogenesis, but results from epidemiologic studies are inconsistent. We investigated associations of omega-3 fatty acids with risk of colorectal adenomas in a case-control study, and whether they were modified by nonsteroidal anti-inflammatory drug (NSAID) use. Methods: The MAP I study was a community-, colonoscopy-based case-control study of colorectal adenomas. Participants aged 30 - 74 years with no history of colorectal neoplasms who had outpatient colonoscopy were recruited from gastroenterology practices from 1995 to 1997. The final sample included 177 incident sporadic adenoma cases and 228 controls. Prior to undergoing colonoscopy, participants completed questionnaires eliciting demographics, medical history, and dietary intake. Multivariate-adjusted odds ratios (OR) were calculated using logistic regression models. Results: Cases were older, more often men, and did not regularly take NSAIDs. Higher levels of omega-3 fatty acids were associated with more than a doubling of risk of adenomas. In contrast, a higher ratio of omega-3 fatty acids to total fat was associated with a significant nearly halving of adenoma risk. Higher levels of fish were also significantly associated with decreased risk of adenoms (OR 0.37; 95% CI 0.20, 0.68; ptrend = 0.01). The direct associations of omega-3 fatty acids with adenoma was stronger in those with a family history of colorectal cancer (OR 3.6; 95% CI 1.06, 12.24), and those with low total fat intakes (OR 4.45; 95% CI 1.83, 10.82). The inverse associations of fish with adenoma were stronger in those with a family history of colorectal cancer (OR 0.20, 95% CI 0.03, 0.68). Conclusions: In summary, we found statistically significant evidence for reduced risk of colorectal adenoma with higher intakes of fish. However, our findings for omega-3 fatty acid intakes were inconsistent, likely because intakes were homogeneous within the low end of the range of omega-3 fatty intake. Further study of fish and omega-3 fatty acid associations with incident, sporadic colorectal adenoma is indicated, especially in light of widespread use of supplemental omega-3 fatty acids by the general public.

Table of Contents

TABLE OF CONTENTS

INTRODUCTION................................................................. 1
BACKGROUND.................................................................. 2
METHODS......................................................................... 5
RESULTS...........................................................................10
DISCUSSION.....................................................................13
REFERENCES.....................................................................20
TABLES............................................................................26












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