Theses Doctoral

Beliefs about Diet and Colorectal Cancer Prevention in an Urban Population

Zaharek, Marguerite Marie

The American Cancer Society (ACS), American Institute for Cancer Research (AICR) and National Cancer Institute (NCI) advocate regular asymptomatic screening (e.g. colonoscopy) as the best immediate strategy for colorectal cancer (CRC) prevention, but studies also indicate changes in diet can lower risk of developing CRC. Forty-five percent of CRC cases have been estimated preventable through appropriate diet, physical activity and weight management. Despite evidence on the association between diet and CRC risk, few studies have addressed beliefs about diet and CRC prevention. The primary aim of the present cross-sectional study was to explore diet-related beliefs on CRC prevention, and to examine if a relationship exists between beliefs and reported dietary intake.

Participants (n=169) were 50 to 75 years of age, asymptomatic for CRC, middle to low income, predominantly female 133 (78.7%) and Black 115 (68%). One hundred and thirty-four (79.3%) were born outside the continental U.S., and 102 (60.4%) were from Caribbean countries. A total of 113 (66.9%) reported they believed diet can prevent CRC, 75 (44.4%) without being probed specifically about diet, and 38 (22.5%) additional when probed. There were no statistically significant differences in believing diet can prevent CRC by age, gender or ethnicity, but there were differences between whites and non-whites (p=.044). Other characteristics associated with belief in diet for CRC prevention included household income greater than $50,000 (p=.005), education greater than high school (p=.001) and normal body mass index (BMI) (p=.001). Among women, believing diet prevents CRC was associated with greater engagement in other preventive health behaviors (p=.009). Reported beliefs reflected national dietary recommendations, and the top most frequently mentioned dietary beliefs were: Increasing dietary fiber, vegetables and fruits, and decreasing red meat, fat and processed meats. Those who believed diet can prevent CRC had healthier intakes for dietary fiber (p=.005), fruit, vegetable, bean (p=.027) vitamin C (p=.039), red meat (p=.032) and cholesterol (p=.045).

Beliefs for specific foods to prevent CRC (e.g. more dietary fiber, more fruits/vegetables, less meat, etc.) were suggestive of healthier intake patterns, but none of these findings were statistically significant. When a healthy diet composite score was created based on intake of at least three servings of fruits and vegetables and less than 35% calories from fat, there were statistically significant differences between those who believed diet plays a role in CRC prevention. Sixty-five (74.7%) of those who had a healthy diet believed diet can prevent CRC, in comparison to only 48 (58.5%) of those who did not have a healthy diet (p=.039).

This study demonstrated an association between beliefs and food intake in an urban and predominantly immigrant sample of men and women. Findings revealed that most people may already believe dietary factors can prevent CRC, and therefore nutrition education efforts should capitalize on these perspectives to encourage healthy food-related behaviors. The promotion of appropriate food choices through nutrition education messages that address beliefs about CRC prevention can potentially reinforce and further strengthen existing sentiments. However, one third of the participants did not believe dietary intake can prevent CRC, thus indicating a need for nutrition education and strategies to target those who are less likely to embrace the benefits of a healthy dietary pattern.


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More About This Work

Academic Units
Behavioral Nutrition
Thesis Advisors
Wolf, Randi L.
Ph.D., Columbia University
Published Here
May 23, 2013