Journal of occupational medicine. : official publication of the Industrial Medical Association最新文献

This article discusses historical and social reasons for the emergence of women's occupational cancer as a current area of research interest. It develops background information on relationships between social and occupational factors that must be considered if research on women, work, and cancer is to be well designed. These factors include specific occupational titles and tasks and the socioeconomic status and roles of women being studied. In addition, detailed demographic data on the industrial and occupational distribution of female workers are provided as one basis for setting priorities for women's occupational cancer studies. These demographic data are supplemented by analysis of specific potential exposures to carcinogens and other hazardous substances. By comparing lists of known and suspected carcinogens published by the International Agency for Research on Cancer to the industries and uses listed by the Hazardous Substances Data Base of the National Library of Medicine, a new target list of industries of significance to female workers was derived. Its implications are discussed herein.

The study of occupational diseases among women has been minimal, and when observations of adverse health effects have been made, they often have been obscured, ignored, or mismanaged. Occupational exposures of women to beryllium, benzene, and vinyl chloride serve as past examples of indifference to the plight of women in the workplace. The lack of regulation for waste anesthetic gases and antineoplastic drugs to protect health care workers and veterinarians indicates that this indifference continues today.

Ovarian cancer risk factors may be genetic, reproductive, or hormonal in nature. Occupational exposure to talc and other carcinogenic substances has not been studied in relation to ovarian cancer risk. We therefore examined the job histories of 296 women aged 20 to 79 who were diagnosed with epithelial ovarian cancer in the Washington, DC area in 1978 to 1981, comparing them to 343 hospital controls, matched for age and race. A blind exposure assessment, evaluating each job/industry combination for potential exposure to talc, ionizing radiation, polycyclic aromatic hydrocarbons, and solvents was conducted by an industrial hygienist blind to case-control status. Women exposed to talc had a relative risk of ovarian cancer below the null, but the confidence interval was wide and there was no evidence of a trend. Women exposed to polycyclic aromatic hydrocarbons had an elevated relative risk, also with a wide confidence interval and no evidence of a trend with duration.

A cohort study was conducted of 616 German female workers with a history of exposure to asbestos. Standardized proportionate mortality analysis was done except for mesothelioma, for which proportionate mortality was computed based on best evident cause of death. Mortality from lung cancer was increased three times over expected value. Death rates due to mesothelioma were 340 times higher than in the general population. Female mortality rates surpassed those observed in men twofold for lung cancer and fourfold for mesothelioma. In comparison with published data from international cohort studies, the observed mortality for mesothelioma in our female cohort appeared higher than that previously reported. German women with a history of asbestos exposure are considered a high-risk group for developing mesothelioma and lung cancer. They should be a target group for intervention strategies (eg, chemoprevention, smoking cessation, early cancer detection).

A cohort mortality study was conducted among 9028 (3042 women, 5986 men) workers potentially exposed to chlorinated naphthalenes (chloracnegens structurally similar to dioxins) and asbestos in the manufacture of Navy cable during World War II. Based on mortality through December 31, 1985, standardized mortality ratios (SMRs) for all cancers was 1.03 in women (95% confidence interval [CI] = 0.9 to 1.17) and 1.18 in men (95% CI = 1.10 to 1.26). There were no significant elevations in causes of death hypothesized a prior to be associated with chlorinated naphthalene exposure (malignant neoplasms [MN] of connective tissue, liver, and lymphatic and hematopoietic organs). An excess of MN of the connective tissue was suggested for workers with over 1 year of exposure and 25 years of latency (SMR = 3.54; 95% CI = 0.97 to 9.07). Among cancer sites not hypothesized to be related a priori, three showed concordant excesses among both genders (MN of stomach; rectum; and trachea, bronchus, and lung). No significant elevations occurred in hormonally related cancers among women. Cancer mortality among 460 individuals with chloracne (431 men, 29 women) was similar to that of the entire cohort, although the chloracne subcohort showed significant excesses in two rare causes of death (MN of esophagus, SMR = 3.26; "benign and unspecified neoplasms," SMR = 4.93). Use of county referent rates decreased SMRs for stomach, rectal, and buccal cavity cancer, suggesting a role for nonoccupational risk factors. It is difficult to draw conclusions about carcinogenicity of chlorinated naphthalenes because of study limitations, most importantly, concomitant asbestos exposure and the relatively short duration of exposure to chlorinated naphthalenes among most of the cohort.

Exposure assessments for occupational epidemiological studies are typically conducted to (1) establish risk gradients with exposure, evaluating a potential causal relationship, or (2) estimate exposure-response dosimetry for quantitative risk calculations. Unavailable quantitative exposure data require use of surrogate or qualitative measures. Differences in women's employment patterns may make surrogate measures less reliable, resulting in systematic errors. Exposures associated with traditionally female careers have not been fully evaluated. Occupational cohorts are often defined to include workers with a minimum employment duration or employment for some minimum time in exposure-related jobs, thereby excluding many women workers. Even when included among studied and exposed worker cohorts, women's domestic exposures may confound risk evaluation. Male/female differences in xenobiotic uptake, distribution, kinetics, and metabolism may affect the relationship between external exposure and resulting biologically effective dose. Clinical factors alter the recognition of disease among women workers, confounding risk determination. Recognizing these problems during design and analysis of occupational cancer epidemiology research is essential to develop valid preventive strategies.

Several studies have examined disease risks for women separately from risks for men, but few have examined exposure differences. This report used data from an epidemiological study of formaldehyde workers to compare formaldehyde exposures between men and women. Exposures were estimated from historical monitoring results, walk-through workplace surveys, interviews with long-term workers, and reviews of historical records. The mean of the exposures in the first job, the last job, and the highest exposed job were calculated by gender. Differences were found when all subjects were included in the analysis (men having higher exposures, on average, than women), but when nonexposed subjects were removed (40% of women, 6% of men), differences were minor. There was a substantial difference in the estimated peak exposure between men and women that decreased, but remained, when only exposed subjects were included. Evaluation of exposures in 1940 to 1945, 1965, and 1979 found that women had a higher average exposure than men in 1940 to 1945, but this pattern was reversed in 1965. By 1979, the average difference between the two genders had disappeared. A comparison of cumulative exposure found that exposed women had half the total exposure of exposed men. More men than women were exposed to other chemicals. Women tended to predominate in clerical, laboratory, assembly, finishing, inspecting, packing, and shipping jobs.

Animal bioassays for carcinogenicity are essential components of occupational health studies. Animal data that have been collected under controlled experimental conditions provide definitive information about the carcinogenic activities of individual substances or defined mixtures and their relative potencies in the test species. Such information serves as a frame of reference for clinical and epidemiologic studies, pointing to potential adverse health effects and to the types of substances that might produce them. This article alerts the occupational and environmental health communities to 20 substances that produced breast tumors, 13 substances that produced uterine tumors, and 8 substances that produced ovarian tumors in long-term National Toxicology Program animal studies. Each of the substances also produced neoplasms at other body sites. Follow-up studies of molecular measures of exposure and response in people and in animals will reduce the uncertainties of transspecies extrapolations.

A cohort study of dry-cleaning workers (1109 women, 592 men) in the mid-1980s revealed significant excess bladder cancer mortality. This article updates vital status through 1990. Significant excesses were seen for bladder cancer (nine deaths, standardized mortality ratio [SMR] = 2.54, 95% confidence interval [CI] = 1.16-4.82), esophageal cancer (10 deaths, SMR = 2.14, 95% CI = 1.02-3.94), and intestinal cancer (26 deaths, SMR = 1.56, 95% CI = 1.02-2.29). In a subcohort exposed only to perchloroethylene (PCE), those with 5 or more years of employment and 20 or more years since first exposure had a significant increased risk of esophageal cancer (four deaths, SMR = 7.17, 95% CI = 1.92-19.82). Women had significant excess esophageal cancer (five deaths, SMR = 3.24, 95% CI = 1.05-7.58) and elevated SMRs for intestinal, pancreatic, and bladder cancer mortality. This study confirms the esophageal cancer risk among dry-cleaning workers seen in another study and suggests an association with PCE. It further documents the risks for intestinal, pancreatic, and bladder cancers in this industry.

Gender differences in risk for leukemia and other selected and combined disease categories were examined by major occupational category for 74,828 benzene-exposed workers compared to 35,805 unexposed workers from 12 cities in China. No significant differences in the relative risks for total mortality and cancer mortality were found between female and male benzene-exposed workers, although risks tended to be somewhat higher among male than among female employees. Both female and male workers in several occupational categories had notably increased risks for all hematopoietic and lymphoproliferative (HLP) malignant and nonmalignant disorders combined and for total leukemia. Variation in risk for HLP disorders by occupational category was observed in both genders, with highest risks for male and female chemical manufacturing workers, female nonproduction employees, and male printers. However, the numbers of leukemia and other HLP malignancies in each category were small. The findings suggest that both female and male benzene-exposed workers in several occupational categories experience excess leukemia and other HLP disorders with relatively minor gender differences. Although this population is one of the largest cohorts of benzene-exposed workers studied to date, evaluation of the observed variation in risk for HLP neoplasms among the occupational groups for workers of each gender is limited by the small numbers of these relatively rare malignancies.