LUNG CANCER RISK ATTRIBUTABLE TO OCCUPATION: IN A CASE CONTROL STUDY IN BLACK SOUTH AFRICANS 2001-2008
Lung cancer is the 4th most common malignancy in South Africa. Although smoking is a well established risk factor, the role of occupational exposures in the local setting is not clear. We estimated the lung cancer risk attributable to common South African occupations.
METHODS:
Data from the on-going Johannesburg Cancer Case-Control Study (JCCCS) of black African adult cancer patients (2001-2008) was used. Information from 579 lung cancer cases and 1120 frequency matched controls was analysed. Controls were randomly selected from cancers not known to be associated with the effects of tobacco, matched by sex and age (±5years). Usual occupation and/or workplace stated at interview were used as an indicator of occupational exposure. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression and attributable fraction (AF) by Miettinen’s formula, adjusted for smoking pack years, HIV status and domestic fuel type use.
RESULTS:
The mean age of cases and controls was 56.0 and 57.1 respectively. Among men the adjusted OR for lung cancer was 3.0 (95% CI 1.4-6.4) in miners and 1.7 (95% CI 1.3-3.2) in those working in transport occupations. In women working as domestic worker (maids, child minders etc) the adjusted OR was 7.3 (95% CI 1.7-11.3) whereas working in the food & beverage industry, the adjusted OR was 4.9 (95% CI 1.4-26.8). Occupation / workplace resulted in an AF of 14% in men and 26% in women.
CONCLUSIONS:
Occupational risk factors for lung cancer in South Africa are gender-specific, having more impact in women than in men. Further studies are needed to assess possible specific exposures in the mining and transport industries for men, and food industry and private homes for women.