Adherence to WCRF/AICR Cancer Prevention Recommendations and Incident Sporadic Colorectal Adenoma Risk Open Access

Song, Yongjia (2016)

Permanent URL: https://etd.library.emory.edu/concern/etds/m039k496r?locale=en
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Abstract

Colorectal cancer is the second most common cause of cancer death in the United States. Though colorectal cancer incidence has been decreasing mainly due to advances in screening, there is need to develop comprehensive recommendations for cancer prevention with diet and lifestyle. The goal of this thesis is to investigate the association between adherence to the WCRF/AICR cancer prevention recommendations and incident, sporadic colorectal adenoma.

A case-control study was conducted by Minnesota Cancer Prevention Research Unit from 1991 to 1994, and included 574 colorectal adenoma cases, 707 colonoscopy-negative controls, and 550 community-based controls. Data on demographics, diet, and lifestyle were collected to construct a 7-component score based on the WCRF/AICR cancer prevention recommendations. Logistic regression models were used to estimate associations between the computed score and its sub-components with incident, sporadic colorectal adenoma risk.Higher adherence to the WCRF/AICR recommendations was borderline statistically significantly associated with lower risk for incident, sporadic colorectal adenoma (OR = 0.69, 95% CI: 0.47, 1.01; Ptrend = 0.027) when comparing cases with community controls. This inverse association was somewhat stronger among men (OR = 0.66, 95% CI: 0.40, 0.98; Ptrend = 0.023) compared to women (OR = 0.72, 95% CI: 0.40, 1.31; Ptrend = 0.524), but interaction by sex was not statistically significant (Pinteraction by sex = 0.155). In analysis comparing cases with endoscopy controls, similar results were obtained (men: OR = 0.50, 95% CI: 0.30, 0.87; Ptrend = 0.012; women: OR = 1.03, 95% CI: 0.50, 1.81; Ptrend = 0.476; Pinteraction by sex < 0.001).

In conclusion, these results support the hypothesis that higher adherence to the WCRF/AICR recommendations were associated with lower risk for incident, sporadic colorectal adenoma.

Table of Contents

Table of Contents

CHAPTER 1. INTRODUCTION AND BACKGROUND ............................................................ 1

Epidemiology of Colorectal Cancer ................................................................................ 1

Molecular Basis of Colorectal Cancer ............................................................................. 3

Risk Factors of Colorectal Cancer .................................................................................. 4

Demographic risk factors ............................................................................................. 4

Family history of colorectal cancer ................................................................................ 5

Physical activity and body fatness ................................................................................. 6

Plant food .................................................................................................................. 7

Animal food ............................................................................................................... 8

Calcium and vitamin D intake ....................................................................................... 8

Alcohol and smoking ................................................................................................... 9

World Cancer Research Fund Recommendations ............................................................ 10

CHAPTER 2. MATERIALS AND METHODS ....................................................................... 13

Study Population ....................................................................................................... 13

Data Collection .......................................................................................................... 14

WCRF/AICR Score Construction ................................................................................... 15

Colorectal Adenoma ................................................................................................... 16

Statistical Methods .................................................................................................... 16

CHAPTER 3. RESULTS AND DISCUSSION ...................................................................... 19

Demographic and Baseline Characteristics .................................................................... 19

Adherence to WCRF/AICR Recommendations ................................................................ 19

Colorectal Adenoma Characteristics ............................................................................. 22

Discussion ................................................................................................................ 23

8

CHAPTER 4. PUBLIC HEALTH IMPLICATIONS .................................................................. 29

REFERENCES ............................................................................................................. 30

LIST OF TABLES ........................................................................................................ 37

Table 1. WCRF Goals and Recommendations on Food, Nutrition, Physical Activity ................37

Table 2. WCRF/ACIR dietary and lifestyle recommendations and corresponding score

construction in CPRU study, 1991-1994. ....................................................................... 39

Table 3. Demographic and dietary characteristics of study participant by case-control

status, CPRU study, 1991-1994. ................................................................................... 42

Table 4. The association of sporadic colorectal adenoma incidence with categories of

the WCRF/AICR score and each component in CPRU study for all participants and

men and women separately, adjusted for age and sex (all participants analysis only)........... 45

Table 5. Multivariable-adjusted associations of the WCRF/AICR score and its

individual components with incident sporadic colorectal adenoma risk in CPRU study,

1991-1994. ............................................................................................................... 47

Table 6. The association of sporadic colorectal adenoma incidence per 1 unit increase

in the WCRF/AICR score by categories of potential effect modifiers, CPRU study,

1991-1994. ............................................................................................................... 49

Table 7 The association of the WCRF/AICR score (per 1 unit increase) with incident,

sporadic colorectal adenoma by colorectal adenoma characteristicsa, CPRU study,

1991-1994. ............................................................................................................... 51

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