Association between Ultra-processed Food Consumption and History of Colorectal Cancer among U.S. Adults: A Cross-sectional Analysis of National Health and Nutrition Examination Survey (2017– March 2020)

Abstract

Background: Ultra-processed foods constitute a substantial proportion of dietary intake among U.S. adults and have been associated with several chronic diseases. Evidence regarding their relationship with colorectal cancer remains limited and inconsistent, particularly in nationally representative populations. Objective: To examine the association between ultra-processed food consumption and a history of colorectal cancer among U.S. adults. Methods: This cross-sectional study used NHANES 2017–March 2020 pre-pandemic data. Foods reported during the Day 1 24-hour dietary recall were classified according to the NOVA system. Ultra-processed food intake was expressed as a percentage of total daily energy intake and categorised into quartiles. A history of colorectal cancer was identified using the Medical Conditions Questionnaire. Survey-weighted logistic regression was performed with adjustment for age, sex, race and ethnicity, educational attainment, body mass index, diabetes, hypertension, smoking status, and physical activity. Results: The analytic sample included 7,372 adults, of whom 58 reported a history of colorectal cancer, representing approximately 232,402,091 U.S. adults. The weighted prevalence of colorectal cancer ranged from 0.43% to 0.89% across quartiles of ultra-processed food intake. Compared with the lowest quartile, the adjusted odds ratios were 1.66 (95% CI, 0.45–6.20) for the second quartile, 0.96 (95% CI, 0.31–3.03) for the third quartile, and 1.34 (95% CI, 0.47–3.85) for the highest quartile. None of these estimates was statistically significant, and the confidence intervals were wide. Conclusions: This cross-sectional analysis did not identify a statistically significant association between ultra-processed food intake and a history of colorectal cancer. However, the small number of colorectal cancer cases, wide confidence intervals, use of a single dietary recall, and inability to establish temporality limit the interpretation of the findings. The results should not be considered evidence that an association is absent. Larger prospective studies using repeated dietary assessments and validated incident colorectal cancer outcomes are needed.