A case–control study of risk factors for colorectal cancer in an African population

Abstract

The interplay between hereditary and environmental factors in the causation of colorectal cancer in sub-Saharan Africa is poorly understood. We carried out a community based case-control study to identify the risk factors associated with colorectal cancer in Zimbabwe. We recruited 101 cases of colorectal cancer and 202 controls, matched for age, sex and domicile. Potential risk factors including family history, socioeconomic status, urbanization, diabetes mellitus and previous schistosomiasis were evaluated. Conditional logistic regression was used to estimate the odds ratios associated with the different factors. Cases were more likely to have a tertiary education (32.7 vs. 13.4%, P<0.001) and a higher income (18.8 vs. 6.9%, P=0.002). After multivariate analysis, diabetes mellitus [odds ratio (OR): 5.3; 95% confidence interval (CI): 1.4-19.9; P=0.012], previous urban domicile (OR: 2.8; 95% CI: 1.0-7.8; P=0.042), previous schistosomiasis (OR: 2.4; 95% CI: 1.4-4.2; P=0.001) and cancer in a first-degree relative (OR: 2.4; 95% CI: 1.2-4.8; P=0.018) were associated independently with colorectal cancer. Our findings suggest that family history, diabetes mellitus, previous schistosomiasis and approximation to a western lifestyle are the predominant associations with colorectal cancer in Africans. This offers opportunities for targeted prevention and hypothesis-driven research into the aetiology of colorectal cancer in this population.

Comparison of the clinicopathological features and prognoses of patients with schistosomal and nonschistosomal colorectal cancer

“…The incidence of CRC in developed countries is significantly higher compared with developing countries, which is associated with factors such as high caloric intake (36) and higher obesity rates (35). Several recent studies have suggested that the occurrence of CRC is associated with certain pathogen infections, such as infections with bacteria (37,38), parasites (15,39) and other infection sources, such as human bocavirus (40).…”

“…Several studies have suggested that long-term inflammation caused by chronic schistosomal infection is a key factor in the carcinogenic process of CRC (12,13). However, there are only a few studies which have reported differences in the characteristics between patients with schistosomal and nonschistosomal CRC and the number of reported schistosomal CRC cases is low (14,15). Thus, it is difficult to accurately describe the difference between schistosomal and nonschistosomal CRC.…”

Dietary patterns and colorectal cancer risk in Zimbabwe: A population based case-control study

“…The study design and population have been described previously [ 15 ]. Briefly, a population based case-control study of adult black Zimbabweans with colorectal cancer and community based controls was carried out.…”

<em>CTLA4</em> tagging polymorphisms and risk of colorectal cancer: a case&ndash;control study involving 2,306 subjects

“… 2 , 3 These may be attributed to certain lifestyles and environmental factors, including physically inactive, overweight, smoking, and drinking. Recently, Katsidzira et al 4 reported that diabetes mellitus, previous schistosomiasis, approximation to a western lifestyle, and family history were the predominant associations with CRC. Besides these unhealthy lifestyle and environmental risk factors, genetic factors may also affect the development of CRC.…”