Cancer risks among iron and steel workers in Anshan, China, Part I: Proportional mortality ratio analysis.

A standardized proportional mortality ratio (SPMR) study of 8,887 deaths during 1980-1989 among male workers in a large integrated iron-steel complex in Anshan, China, was conducted to provide clues to occupational risk factors. Accidents and cancer accounted for a higher proportion of deaths among the iron-steel workers than among the general male population (SPMR = 1.21; 95% CI = 1.12-1.31 and 1.14; 95% CI = 1.10-1.18, respectively). Among all workers, SPMRs were significantly elevated for stomach, lung, and colorectal cancers (SPMR = 1.37, 1.37, 1.38, respectively), but not other cancers. Risks of stomach cancer appeared to be highest among workers employed in jobs with exposure to iron and coal dust, whereas significant increases in colorectal cancer were seen for loading and other dusty jobs and for administrative and sedentary jobs without dust exposure. Risks of lung cancer appeared increased for a variety of jobs throughout the complex, especially those with probable high levels of exposure to polycyclic hydrocarbons and asbestos. Risk of esophageal cancer was significantly elevated for fire-resistant brick makers, and risk of nonmalignant respiratory disease was significantly elevated for those employed as furnace workers, foundry workers, and fire-resistant brick makers.

Cancer risks among iron and steel workers in Anshan, China, Part II: Case-control studies of lung and stomach cancer.

Nested case-control interview studies of lung cancer (610 incident cases), stomach cancer (292 incident cases), and 959 controls were conducted to follow up leads from a proportional mortality analysis of deaths among male workers in a large integrated iron-steel complex in Anshan, China. For lung cancer, after adjusting for the significant non-occupational risk factors (smoking, other pulmonary disease, family history of lung cancer, and low consumption of fruit or tea), risks were significantly elevated for those employed for 15 or more years in smelting and rolling (OR = 1.5, CI = 1.1-2.2), in the fire-resistant brick factory (OR = 2.9, CI = 1.4-5.9), in general loading (OR = 2.5, CI = 1.0-6.1), and as coke oven workers (OR = 3.4; CI = 1.4-8.5). For stomach cancer, after adjusting for consumption of pickled vegetables, prior gastric diseases, family history of stomach cancer, low intake of fruits and vegetables, and education, risks were significantly elevated for those employed for 15 or more years in ore sintering and transportation (OR = 2.1, CI = 1.0-4.4), in the fire-resistant brick factory (OR = 2.5, CI = 1.1-5.8), in general loading (OR = 3.2, CI = 1.2-8.9), as boilerworkers and cooks (OR = 2.6, CI = 1.2-5.6), and as coke oven workers (OR = 5.4, CI = 1.8-16.0). For both lung and stomach cancers, significant dose-response gradients were observed for exposure to total dust and benzo(a)pyrene, but not for specific chemical components of dust. Overall, long-term steel workers with exposure to workplace pollutants had a 40% increased risk of both lung and stomach cancers. These case-control studies confirm many of the occupational findings reported in the proportionate mortality analysis, and suggest avenues for further work to evaluate the carcinogenicity of individual components of dust.

Lifestyle, environmental pollution and lung cancer in cities of Liaoning in northeastern China.

Several studies were conducted in cities of Liaoning Province, one of the areas of China with heavy concentrations of industry, to investigate the effects of life-style factors and environmental pollutants on lung cancer causation. A case-control study involving 1249 lung cancer patients and 1345 population-based controls was conducted in 1985-1988 in Shenyang, the capital of Liaoning. Cigarette smoking was found to be the principal cause of lung cancer in this population, accounting for 55% of the disease in males and 37% in females. There was also a significant increase in lung cancer risk associated with an overall index of indoor air pollution due to coal-burning emission. The population attributable risk (PAR) for indoor air pollution was 13% for males and 17% for females. Risks were significantly increased for workers in the non-ferrous smelter (odds ratio (OR) = 2.6, 95% CI, 1.3-5.1), chemical and drug manufacturing (OR = 3.0, 95% CI, 1.0-8.0), and the glass and pottery industry (OR = 1.6, 95% CI, 1.0-2.5). Studies in the Anshan Iron-Steel Complex showed a significant excess of lung cancer for workers exposed to a variety of dusts. A standardized proportional mortality ratio (SPMR) study of 8887 deaths during 1980-1989 among male workers of the complex indicated a 37% excess risk of lung cancer compared to residents of the city. A nested case-control study was then conducted in that complex. A total of 610 cases of lung cancer diagnosed during 1987-1993 and 959 randomly selected controls from 196 993 active and retired employees of the complex were interviewed. Historical monitoring records for dust and benzo(a)pyrene (B(a)P) were collected from 1956-1992 to calculate cumulative exposure for each person. Results suggested that risks were increased for all occupations in which there was exposure to dusts, with the highest risks seen among coke oven workers (OR = 3.5, 95% CI, 2.0-6.4) and fire-resistant brick makers (OR = 2.9, 95% CI, 1.9-4.4). Significant dose-response patterns between cumulative total dust, cumulative total B(a)P and lung cancer risk were observed. The findings suggest that smoking and environmental pollution combine to account for elevated rates of lung cancer in cities of northeastern China.