AN EPIDEMIOLOGIC-STUDY OF RISK-FACTORS FOR LUNG-CANCER IN GUANGZHOU, CHINA

Citation
Yx. Du et al., AN EPIDEMIOLOGIC-STUDY OF RISK-FACTORS FOR LUNG-CANCER IN GUANGZHOU, CHINA, Lung cancer, 14, 1996, pp. 9-37
Citations number
24
Categorie Soggetti
Oncology
Journal title
ISSN journal
01695002
Volume
14
Year of publication
1996
Supplement
1
Pages
9 - 37
Database
ISI
SICI code
0169-5002(1996)14:<9:AEORFL>2.0.ZU;2-K
Abstract
Lung cancer has been on a rapid rise worldwide during the last three o r four decades, in part due to modern social habits and unhealthy life styles. Although smoking, air pollution, and certain types of occupati onal exposure have been recognized as the major risk factors for lung cancer, the significance of each of these factors appears to vary with sex, country, and with region within a given country. In the case of nonsmoking females, some risk factors for lung cancer remain to be ide ntified. In the city of Guangzhou, lung cancer is one of the five lead ing tumors and the rate has been increasing steadily in both males and females since the 1970s. In this report, more than 6000 cases of lung cancer deaths, accumulated over the past 9 years, were analyzed. The severity of air pollution and cigarette smoking were positively correl ated with the incidence of lung cancer deaths. Analysis of levels of S O2 and NOx suggests that the major source of indoor air pollution came from cooking. Two studies were performed in order to determine the re lative contribution and importance of smoking, indoor air pollution an d occupational exposure as risk factors for the rising incidence of lu ng cancer. The first was a population-based case-control study involvi ng 849 subjects (566 males and 283 females). The second study was base d on the data made available by the Third National Census survey, in w hich the standardized mortality rate (SMR) and population attributable risk (PAR) for lung cancer due to occupational exposure for the popul ation in Guangzhou were analyzed. Results of these two studies show th at: in females, indoor air pollution, derived primarily from burning c oal, was found to be a highly significant risk factor for lung cancer. In males, however, cigarette smoking and occupational exposure were s ignificantly associated with lung cancer. To further elucidate the con tribution of indoor air pollution as a risk factor for lung cancer in nonsmoking females, two additional case-control studies were performed in 1985 and 1986. The 1985 study involved 120 nonsmokers (28 males, 9 2 females) in which the influence of such lifestyle factors as: person al history of nonmalignant respiratory diseases, fresh vegetable consu mption, lifetime occupation and occupational exposure histories, expos ure to environmental tobacco smoke (ETS), degree of indoor air polluti on, general conditions of home residence, cooking practices and enviro nments, and family history of cancer were first individually assessed and then collectively subjected to multiple conditional regression ana lysis for evaluation as risk factors for lung cancer. The 1986 study i nvolved 75 cases of never-smoking females in which the aim was to inve stigate the influence of exposure to spousal smoke as a risk factor fo r lung cancer. These studies suggest that consumption of fresh vegetab les was a ''protective'' factor for lung cancer in both males and fema les. In females, indoor air pollution and size of the kitchen were ris k factors for lung cancer, whereas ETS exposure, respiratory disease h istory, family history of cancer, living conditions, use of cooking fu el, and participation in cooking, were not statistically associated wi th female lung cancer deaths. Occupational exposure was also correlate d with the incidence of female lung cancer deaths. In males, chemists had the highest SMR, whereas in females, homemakers had the highest SM R.In males, the most common lung cancer cell type was squamous cell ca rcinoma, whereas in females adenocarcinoma was the most predominant ty pe. The factors affecting the distribution of histologic lung cancer c ell types were also investigated and discussed.