Food groups and colon cancer risk in African‐Americans and Caucasians

Abstract

The disparities in colon cancer incidence between AfricanAmericans and other U.S. ethnic groups are largely unexplained. This report examines associations of various food groups with colon cancer in African-Americans and Caucasians from a case-control study. Incident cases of histologically confirmed colon cancer, age 40 -80 years, (n ‫؍‬ 613) and matched controls (n ‫؍‬ 996) were interviewed in-person to ascertain potential colon cancer risk factors. Diet over the year before diagnosis or interview date was assessed using a validated food frequency questionnaire adapted to include regional foods. Multivariate logistic regression models estimated energy-adjusted and non-energy adjusted odds ratios (OR). Controls generally reported higher consumption (daily amount and weekly frequency) of fruits, vegetables and dark green, deep yellow fruits/vegetables, whereas cases consumed more refined carbohydrates and fats, oils and snacks. Regardless of ethnic group or energy adjustment, high and frequent vegetable consumption (particularly dark green vegetables) was protective, consistent with 20 -50% reductions in risk. In Caucasians, high refined carbohydrate and red meat consumption (amount and frequency) was associated with a statistically significant 2-fold increased risk in non-energy adjusted models. In African-Americans, frequent intake of dairy foods was associated with a doubling in risk (OR ‫؍‬ 1.9, 95% CI ‫؍‬ 1.1-3.4) in non-energy-adjusted models, whereas frequent fruit consumption correlated with a nonsignificant 30% lower risk. These findings add to growing evidence that plant foods may protect against colon cancer; however, the effects of the other food groups varied by ethnic group and energy adjustment. These results may also explain some of the ethnic differences in colon cancer incidence. © 2004 Wiley-Liss, Inc. Key words: African-Americans; colon cancer; diet; foods; food groups; ethnic group; CaucasiansCarcinoma of the colon is one of the most common cancers in developed countries. 1 In the United States (U.S.), colon cancer is the second leading cause of cancer death and the third most common cancer among adults, accounting for approximately 15% of all cancers diagnosed annually. 2,3 The American Cancer Society projects that in the year 2003, 147,500 new colon and rectal cancer cases will be diagnosed and an estimated 57,100 persons will die from these cancers. 4 Colon cancer incidence and mortality vary markedly by ethnic group; specifically, African-Americans have the highest incidence and mortality rates among all U.S. ethnic groups. 3,4 Between 1992-99, for example, colon and rectal cancer incidence and mortality rates were 61.9 and 29.1 per 100,000 respectively among African-Americans. In contrast, for Caucasians, these rates were 51.9 and 21.9 per 100,000, respectively. 3 The reasons for ethnic differences in incidence rates for colon cancer are largely unknown. Socioeconomic, behavioral, cultural and health care differences undoubtedly contribute to some of these disparities but do not complet...

Diet, Lifestyle, and Genomic Instability in the North Carolina Colon Cancer Study

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