Risk factors associated with oesophageal cancer in Bulawayo, Zimbabwe

Abstract

This report presents information on risk factors for oesophageal cancer in Bulawayo, Zimbabwe. The data analysed were from the Cancer Registry of Bulawayo for the years 1963-77, when all registered patients were interviewed using a standard questionnaire. The age-standardised incidence rates in the urban population of Bulawayo in the first 10 year period were 58.6 per 100,000 in men and 8.1 in women. The distribution of risk factors was assessed in 881 oesophageal cancer cases (826 male, 55 female) and a control group comprising other non-tobacco- and non-alcohol-related cancer (5238) cases. There was a marked geographical gradient in risk in both sexes, which remained after adjustment for lifestyle variables. In men tobacco smoking was significantly associated with risk of oesophageal cancer, with the relative risk rising to 5.7 among smokers of 15 or more g day-1; this effect is independent of alcohol drinking. Among women who had ever smoked tobacco, the relative risk was 4.0 compared with those who had never smoked. Alcohol intake showed no independent effect on risk. Low socioeconomic status [odds ratio (OR) = 1.5; confidence interval (CI) = 1.0-2.1] and working as a miner (OR = 2.5; CI = 1.5-4.2) conferred increased risks in comparison with men of high socioeconomic status.