Colorectal cancer: A case-control study of dietary factors in an indigenous East African population.

Wismayer R, Kiwanuka J, Wabinga H and Odida M

Published on: 2023-03-26

Abstract

Introduction: Low-income countries in East Africa have a lower incidence of colorectal cancer (CRC) than high-income countries; however, the incidence has steadily increased in the last few decades. In East Africa, the extent to which genetic and environmental factors, particularly dietary factors, contribute to the aetiology of CRC is unclear. Therefore, the objective of our study was to determine the relationship between dietary factors and CRC in an indigenous population in East Africa.

Methods: We conducted a case-control study and recruited 128 cases and 256 controls, block-matched for age (±5 years) and sex. Data regarding diet were obtained from all the participants using an interview-based questionnaire. The potential dietary risk factors and protective factors evaluated included the type, frequency of meat consumed and the type and frequency of fibre foods consumed. The frequency was either 4x and above/week or 2-3x/week or 1x/week or never. Ordinal and conditional logistic regression analyses were used to determine the odds ratios associated with the different risk and protective factors.

Results: The mean age (IQR) for the case participants was 55.5 (43-67.5) years, and that of the control participants was 54 (42-65) years. The male: female ratio was 1:1 for all the participants. The most significant risk factor included the consumption of boiled beef 2-3x/week (aOR: 3.24; p<0.035). Consumption of high fibre foods, including: - millet for ≥4x/week (aOR: 0.23; p=0.003)), spinach for ≥4x/week (aOR: 0.32; p=0.043), and potatoes 2-3x/week (aOR: 0.30; p=0.044), were protective against CRC. Cassava showed a tendency to reduce the likelihood of CRC when consumed ≥4x/week (aOR: 0.38) however this did not reach statistical significance (p=0.093).

Conclusions: The consumption of boiled beef increases the risk of CRC, while the intake of high-fibre foods may reduce the risk of CRC among Ugandans. We recommend nutritional educational programmes to increase public awareness regarding the protective role of a high-fibre diet and to limit the intake of cooked meat in our indigenous East African population.