Effects of tobacco smoking on cancer and cardiovascular disease in urban black South Africans

Abstract

Demographic and lifestyle information from 9690 black patients diagnosed with cancer or cardiovascular disease was collected in an ongoing case -control study in Johannesburg, South Africa. Compared to never smokers, the odds ratio (OR) for lung cancer among current smokers was 16.3 (95% confidence interval (CI), 9.6 -27.6) for men and 6.4 (95% CI, 4.0 -10.4) for women. The corresponding OR for other smoking-related cancers was 4.6 (95% CI, 3.7 -5.7) among men and 1.9 (95% CI, 1.6 -2.2) among women, and for cardiovascular disease, 3.4 (95% CI, 2.1 -5.4) among men and 1.5 (95% CI, 1.1 -2.1) among women. Risks were higher among smokers than former smokers, and all risk estimates increased with increasing levels of smoking duration and intensity. Non-electric domestic fuel was associated with approximately 60% increase in the risk of smoking-related cancer, but not cardiovascular disease. Risks for cancers of cervix, oesophagus, oral cavity/pharynx, stomach, larynx, pancreas and anogenital region, as well as squamous cell carcinoma of skin were all significantly higher among current than never-smokers, with ORs ranging from 1.5 for cervix (95% CI, 1.2 -1.8) to 14.7 for larynx (95% CI, 7.2 -30). The risks of tobacco-related disease reported here are similar to that currently observed in Western countries, even though cigarette consumption is relatively low in this population.

Smoking and the Risk of Nonmelanoma Skin Cancer

“…Important factors allowed for were age (20 studies), sex (14 studies), skin type/pigmentation/tendency to burn (5 studies), and exposure to sun/sunburn (6 studies); additionally, the population in one study 27 was based on comparisons between twins. Six of the 25 included studies did not provide data in a suitable format 9,14,21,24,29,32 and thus could not be included in the meta-analyses; however, data for these studies are reported narratively.…”

Oral leukoplakia in a South African sample: a clinicopathological study

“…The low frequency of oral leukoplakia in black persons may be attributed to the fact that in general, black persons seek medical treatment late in the course of their disease, and by the time of diagnosis, the oral leukoplakia has already undergone malignant transformation and progressed to oral squamous cell carcinoma (9,50); and to the fact that in South Africa, black persons smoke tobacco less than do white persons (10,11). Indeed, in this study, 62% of black patients with oral leukoplakia smoked tobacco compared to 82% of white patients with oral leukoplakia (Table VII).…”

“…This apparent low prevalence of oral leukoplakia in black South Africans is difficult to explain. This may be due to the fact that in the pre-1994 era, black people had limited access to government health facilities, that black persons in South Africa smoke less compared to other South African population groups, and that in general, black people seek medical treatment late in the course of their disease and by the time of diagnosis, the oral leukoplakia has already transformed into oral SCC (10,11). It is however possible that for reasons unknown, the prevalence of oral leukoplakia in South African blacks is inherently low.…”

Clinical profile of patients diagnosed with primary lung cancer at the Pulmonology Division, Universitas Academic Hospital, Bloemfontein, 2010-2011

“…According to their observations, education level was inversely associated with the mortality rate of all types of cancer, and the difference was most pronounced in individuals with up to 12 years of education, and in those with more than 12 years of education. 29 In a South African study, Stein et al 11 reported that 68% of black patients with lung cancer had completed a maximum of five years of schooling. According to the United Nations Educational, Scientific and Cultural Organization, in 2011, the mean number of years of school attendance by adults older than 25 years of age in South Africa was 8.5 years, 31 implying that a substantial proportion of the total South African population has an education level of lower than Grade 9.…”