Associations of Fruit and Vegetable Intake with Incident, Sporadic, Colorectal Adenoma Open Access

Burkhardt, Elizabeth Ann (2012)

Permanent URL: https://etd.library.emory.edu/concern/etds/3484zh56j?locale=en
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Abstract


Although associations of fruit and vegetable (F/V) intake with colorectal neoplasms have
been studied extensively, the findings have been inconsistent, perhaps due to differential
distributions of potential effect modifying variables across study populations. We used
data from three case-control studies conducted between 1991 and 2002 to assess
associations of total fruit, total vegetables, and total fruit plus vegetable intakes with
incident, sporadic, colorectal adenoma according to potential effect modifying risk
factors (age, sex, nonsteroidal anti-inflammatory drug [NSAID] use, smoking,
chromosome 8q24 region single nucleotide polymorphisms) and adenoma characteristics
among 792 cases and 985 colonoscopy-negative controls in a pooled analysis, and among
565 cases and 536 community controls in a separate analysis. In comparisons of the
highest to lowest quartiles of F/V intakes, risk estimates were close to the null overall and
in the stratified analyses. The multivariable-adjusted risk estimates that differed the most
from the null included those for fruit intake with adenomas overall in the analysis
involving community controls (odds ratio [OR] 0.78, 95% confidence interval [CI] 0.52-
1.16), among ever smokers in the pooled and community controls analyses (ORs 0.64 [CI
0.42-0.99] and 0.68 [CI 0.41-1.13], respectively), and among those who did not regularly
take an NSAID in the pooled and community control analyses (ORs 0.76 [CI 0.53-1.11]
and 0.70 [CI 0.46-1.08)], respectively). The fruit-adenoma inverse association tended to
be stronger for multiple and distal adenomas and those with more advanced
characteristics; for example, the OR for adenomas with some villous histology was 0.56
(CI 0.32-0.98). However, the OR for the association of vegetable intake with adenomas
among those with the rs7837328 low risk GG genotype was 2.37 (CI 1.09-5.16). These
results provide little to no support for inverse associations of fruit and vegetable intake
with risk for incident, sporadic adenoma, but do provide some support for further
investigations into whether 1) increased fruit intake may reduce risk for advanced
adenomas, especially among persons with higher oxidative stress/inflammation from
smoking or not taking an anti-inflammatory drug, and 2) chromosome 8q24 region
genotypes may modify associations of vegetable intake with adenomas.

Table of Contents

Table of Contents



Chapter 1: Background

.................................................................................................................1

Chapter 2: Manuscript
Abstract ...................................................................................................16
Introduction ..............................................................................................17
Methods....................................................................................................19
Statistical Analysis .....................................................................................24
Results .................................................................................................... 25
Discussion .................................................................................................27

Chapter 3: Conclusions and Recommendations
Public Health Implications .............................................................................37
Future Directions ........................................................................................38

References ...............................................................................................43

Tables ......................................................................................................47

Appendix: Supplemental Tables ..................................................................53






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