Hereditary, environmental, and dietary risk factors of colorectal cancer: a case-control study in the Algerian East

Colorectal carcinoma (CRC) is the second most common cancer diagnosed in Algeria. The incidence and the mortality rate of CRC have increased so that the nation now ranks third in Africa in both these variables. Many environmental and genetic factors are suspected to play an important role in the development of the disease. This study aimed to identify the risk factors for CRC in Algeria. We performed a case-control study in five Medical Oncology Services in this region: Tebessa, Batna, Annaba, Setif, and Constantine, from 2016 to 2019. Altogether, 200 patients diagnosed with CRC and 200 age-matched controls without any diagnosis of cancer were included. Study participants were interviewed about environmental, dietary, and hereditary risk factors, i.e., family history of cancer, using a questionnaire. Results showed a significant association between high educational level and a decreased risk of CRC. Diagnoses of any cancer or of CRC in first-degree or in second- or third-degree relatives also were significantly associated with CRC risk. Occupational exposures showed a significant link with an increased risk of CRC, as did obesity, alcohol consumption, and passive smoking. Yogurt, cereals, sugar, butter, and margarine consumption were significant protective factors, while cheese, dried fruits, red meat, juice, and fizzy drink consumption was associated with increased risk. Our findings suggest a benefit of public health campaigns to enhance awareness about CRC and to encourage healthy dietary choices and avoidance of non-dietary risk factors.