Lung cancer, tobacco, and environmental factors in the African population of the Northern Province, South Africa

Abstract

Objective-To measure the association between lung cancer and exposure to tobacco, occupational pollution, and environmental pollution. Design-Case-control study among incident African patients with cancer. Questionnaire assessment of exposure to tobacco, occupation, and place of birth. Setting-Northern Province, South Africa. Subjects-Between 1993 and 1995, 288 men and 60 women with lung cancer and 183 male and 197 female controls (consisting of patients newly diagnosed with cancers other than those known to be associated with smoking) were interviewed. Unmatched, unconditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) of developing lung cancer in relation to a number of variables. Main outcome measure-Risk of developing lung cancer related to exposure to tobacco, indoor pollution, dusty work environment, and residential exposure to asbestos. Results-There was a significant increase in the risk of developing lung cancer through smoking. In men, the ORs were 2.2 (95% CI = 1.0 to 4.6) in ex-smokers, 9.8 (95% CI = 5.9 to 16.4) in light smokers (0-14 g/day), and 12.0 (95% CI = 6.5 to 22.3) in heavy smokers. In women, the ORs were 5.8 (95% CI = 1.3 to 25.8) in ex-smokers and 5.5 (95% CI = 2.6 to 11.3) in current smokers. Work in a dusty industry showed an elevated risk (OR = 3.2, 95% CI = 1.8 to 5.8) for lung cancer only in men. Male residents of areas where asbestos was shipped for distribution (termed moderately polluted asbestos areas) had a 2.5-fold increase (95% CI = 1.0 to 4.4) in the risk (OR) of developing lung cancer, and residents of areas where asbestos was mined (termed heavily polluted asbestos areas) had a 2.8-fold increase in risk (95% CI = 0.7 to 10.4). Female residents of heavily polluted asbestos areas showed elevated risks of 5.4 (95% CI = 1.3 to 22.5) of developing lung cancer. Conclusion-The data suggest that tobacco smoking is the most important risk factor for the development of lung cancer in this setting. Risks for lung cancer are reminiscent of those observed in Western countries in the 1960s and 1970s. However, environmental exposure to asbestos, a dusty occupation (in men), and perhaps indoor air pollution may also contribute to the development of lung cancer in this province. (Tobacco Control 1999;8:398-401)

Risk factors for oesophageal, lung, oral and laryngeal cancers in black South Africans

“…The findings of this analysis of oesophageal, lung, oral and laryngeal cancers diagnosed in black patients at state hospitals in Johannesburg are broadly in line with international findings, including studies on lung cancer in Zimbabwe (Parkin et al, 1994), and Northern Province, South Africa (Mzileni et al, 1999); and on oesophageal cancer in Zimbabwe (Parkin et al, 1994) and in Soweto (Segal et al, 1988). Tobacco smoking was the leading risk factor for all of the cancers analysed with both current and former use harmful, and the expected dose-response effect seen.…”

“…Indications of a role for smoking in the development of lung cancer among more urbanised African men from Johannesburg and Natal in South Africa, and Bulawayo in Zimbabwe, have been observed since the 1960s with the incidence of lung cancer already beginning to rise at that time (Bradshaw and Schonland, 1969;Parkin et al, 1994). More recently, a case -control study from the Northern Province of South Africa (which is 88% rural) has described an association between smoking and lung cancer for African men and, for the first time, for African women (Mzileni et al, 1999).…”

Nicotine dependence and problem behaviors among urban South African adolescents

“…In South Africa, an estimated 20,000 adults die from tobacco-related causes per annum (Sitas et al, 2004), and as elsewhere, tobacco use is associated with lung cancer and other diseases (Mzileni, Sitas, Steyn, Carrara, & Bekker, 1999; Sitas et al, 2004). Approximately 31% of South African high school students in Grades 8 to 11 (mean ages 14 – 17) were smokers of tobacco products in 2002, with about one fifth of them being current (past 30-day) smokers (Reddy et al, 2003).…”

The health impact of nonoccupational exposure to asbestos: what do we know?

“…A cohort study that included all Whites born from 1916 through 1936 in the mining town of Prieska in Cape Town province (crocidolite mines) found a significantly excess number of cases of pleural mesothelioma and lung cancer, including among women who had never worked in the asbestos industry (Kielkowski et al, 2000). A case-control study including the cases of lung cancer diagnosed between 1993 and 1995 in another crocidolite mining region, the Northern Province, found an OR of 5.4 (CI = 1.3-22.5) among women who lived in mining areas (Mzileni et al, 1999).…”