Tobacco and alcohol as risk factors for oesophageal cancer in a high incidence area in South Africa

Abstract

BACKGROUND: The Eastern Cape Province of South Africa, which includes the former Transkei has high rates of squamous cell oesophageal cancer (OC), thought to be caused mainly by nutritional deficiencies and fungal contamination of staple maize. A hospital-based case-control study was conducted at three of the major referral hospitals in this region to measure, among other suspected risk factors, the relative importance of tobacco smoking and alcohol consumption for the disease in this population. METHODS: Incident cases (n=670) of OC and controls (n=1188) were interviewed using a structured questionnaire which included questions on tobacco and alcohol-related consumption. Odds ratios (ORs) with 95% confidence intervals for each of the risk factors were calculated using unconditional multiple logistic regression models. RESULTS: A monotonic dose-response was observed across the categories of each tobacco-related variable in both sexes. Males and females currently smoking a total of >14g of tobacco per day were observed to have over 4-times the odds of developing OC (males OR=4.36, 95% CI 2.24-8.48; females OR=4.56, 95% CI 1.46-14.30), with pipe smoking showing the strongest effect. Similar trends were observed for the alcohol-related variables. The quantity of ethanol consumed was the most important factor in OC development rather than any individual type of alcoholic beverage, especially in smokers. Males and females consuming >53g of ethanol per day had approximately 5-times greater odds in comparison to non-drinkers (males OR=4.72, 95% CI 2.64-8.41; females OR=5.24, 95% CI 3.34-8.23) and 8.5 greater odds in those who smoked >14g tobacco daily. The attributable fractions for smoking and alcohol consumption were 58% and 48% respectively, 64% for both factors combined. CONCLUSION: Tobacco and alcohol use are major risk factors for OC development in this region. IMPACT: This study provides evidence for further reinforcement of cessation of smoking and alcohol consumption to curb OC development.