Occupational cancer among women: research status and methodologic considerations

Occupational Cancers among Employed Women: A Narrative Review

The facts that occupational cancer in women is under-investigated, with few in-depth analyses are well known. In recent decades the workforce has changed, with an increasing number of women employed. Therefore, the inclusion of women in occupational cancer studies has become more urgent and feasible than in the past decades. The difficulties to evaluate occupational causes of female gynecologic tumors in most past cohorts and the potential variation in outcome responses between men and women must be taken into consideration. This narrative review discusses women's occupational cancer as a current area of research, focusing on three groups of workers characterized by peculiar exposure to occupational carcinogens and where women are often employed: beauticians and hairdressers; farmers; and healthcare workers. We discuss the most relevant cancers in each working category, with a particular focus on female breast cancer. In the three industries reviewed in detail, there are some risk factors which may affect primarily women, inducing breast cancer and cervical cancer, as well as risk factors that are carcinogenic in both genders, but whose effects are less well known in women.

Occupation- and industry-specific cancer mortality among Japanese women from 1980 to 2015

BACKGROUND

The number of women in Japan who continue working after childbirth is on the rise. Over the past few years, Japan's cancer mortality rate has increased. About 50% of all cancer deaths among Japanese women aged 25-64 are caused by lung, gastric, pancreatic and colorectal cancers. This study aims to examine the difference in mortality risk for key cancers among women and explore the effect of the economic crisis in the mid-1990s separately for occupational and industrial categories.

METHODS

Data from 1980 to 2015 were gathered from the Japanese Population Census and National Vital Statistics conducted in the same year. A Poisson regression analysis was used to estimate mortality risk and mortality trends for lung, gastric, pancreatic and colorectal cancer among Japanese working women aged 25-64 years.

RESULTS

Across most industrial and occupational groups, the trends in age-standardised cancer mortality rate for women have declined. Workers in management, security and transportation have a higher cancer mortality risk than sales workers. The risk of death from all four cancers is higher for workers in the mining and electricity industries than for wholesale and retail workers.

CONCLUSION

To improve the health and well-being of employed Japanese women, it is crucial to monitor cancer mortality trends. Using these population-level quantitative risk estimates, industry- and occupation-specific prevention programmes can be developed to target women at higher cancer risk and enable the early detection and treatment of cancer.

Development of a Data Visualization Tool for Occupational Exposure to Chemicals of Concern for Breast Cancer Among California Working Women, 2010-2014

We identified the occupations that employ California women and a list of chemicals of concern for breast cancer. We evaluated the likelihood of on-the-job exposure to the categories of chemicals by occupation among formally and informally employed women. We selected 145 occupations representing more than 6.6 million women (85% of California working women), along with an additional sixteen occupations for informal workers only. We organized 1012 chemicals (including mammary gland carcinogens, developmental toxicants, and endocrine-disrupting chemicals) into twenty-five categories. More than 80 percent of occupations investigated had possible or probable exposure to at least one category of chemicals. This is the first categorization of occupational exposure to chemicals of concern for breast cancer among California working women. Our investigation revealed significant data gaps, which could be improved by policy changes resulting in enhanced collection of data on occupation and chemical exposure.

Thyroid cancer among female workers in Korea, 2007-2015

Background

Prevalence of thyroid cancer has been increasing rapidly worldwide, especially among women. There has been a debate as to whether such an increase represents consequences of over-diagnosis or a true increase. To find the occupational risk of Korean female workers in different industry sectors, we analyzed the data of Korean female workers.

Methods

National Female Worker Cohort data that contain information on total female workers were used for our analysis of prevalence of thyroid cancer (C73 according to KCD-5, 6 code) derived from National Health Insurance data. By combining industrial codes from National Health Insurance Service and those from Korea Workers' Compensation and Welfare Service, the classification of industrial codes became to consist of the total of thirty three representing both non-office (NO) and office (O) categories. Both an internal comparison among female workers within the cohort and an external comparison to compare female workers with Korean general female population were carried out.

Results

Among 149,258 female workers, 2,641 cases of thyroid cancers were identified. Differences in prevalence of thyroid cancer between female workers (40.5%) and general Korean female population (32.6%) were observed; however, the differences in prevalence of thyroid cancer between NO workers and O workers were not apparent. An analysis involving workers in Financial and insurance activities sector revealed that, standardized prevalence rate (SPR) of both NO (2.96, 95% CI = 2.01-4.20) and O workers (3.68, 95% CI = 3.10-4.33) increased significantly and that an AOR (adjusted odds ratio) increased marginally (1.38, 95% CI = 0.97-1.96). Further, when stratified in respect to the duration of employment, an AOR of female workers having been employed for more than 8 years showed a significant increase (1.63, 95% CI = 1.07-2.49).

Conclusions

Female workers had a higher risk of thyroid cancer than general female population but the difference between NO workers and O workers was not found to be significant in most industrial sectors. Further studies using data with information regarding specific occupational exposures are needed.

A comprehensive approach of the gender bias in occupational cancer epidemiology: A systematic review of lung cancer studies (2003-2014)

BACKGROUND

In occupational epidemiology, a male-centered perspective often predominates. We aimed to describe current research practices in terms of gender consideration at different stages of epidemiological studies.

METHODS

A systematic review of occupational lung cancer publications indexed in PubMed was conducted over the period 2003-2014. Articles were described according to the sex composition of their study sample.

RESULTS

In 243 studies, 7 (3%) were women-only, 101 (41%) were mixed, with a disproportionate men-to-women ratio (P50 = 3.5; P75 = 12.4). A shift was observed from mixed and unspecified source populations to men-only final samples. Our results also suggest implicit generalization of results from men-only studies, a lack of tests of interaction and often unjustified sex-adjustment for mixed studies.

CONCLUSIONS

The lower proportion of women in studies cannot be fully explained by their under-representation in the target populations, since there were large numbers of women among both potentially exposed workers and patients diagnosed with lung cancer.

Chemical Exposures in the Workplace

Occupational health nurses need to be aware of the current science on breast cancer risks in the workplace because they are risk communicators for employees and their families. Occupational health nurses can serve as advocates for necessary research ultimately leading to risk reduction and prevention strategies in the workplace. Current research suggests exposure to organic solvents, metals, acid mists, sterilizing agents (ethylene oxide), some pesticides, light at night (shift work), and tobacco smoke increases breast cancer risk among women in occupational settings. Animal cancer bioassays conducted by the National Toxicology Program indicate more than 40 chemicals can induce mammary tumors, and most of these are still in production. A variety of occupations worldwide, including health care providers and metal, textile, dye, rubber, and plastic manufacturing workers, have been identified as having some evidence of higher breast cancer risk. Although some chemical exposures are suspected to affect breast cancer risk, estimates of or actual exposures to these chemicals in the workplace often have not been determined. Research needed to better identify breast cancer risks in occupational settings includes monitoring breast cancer incidence in occupations with exposures to suspected carcinogens, characterizing chemical exposures by job type and task, determining whether potential gender differences affect chemical exposures, and using molecular approaches to identify gene-environment interactions.

The inclusion of women in studies of occupational cancer: a review of the epidemiologic literature from 1991-2009

INTRODUCTION

Since the early 1990s, researchers have been concerned with the low rate at which women are included in epidemiologic studies of occupational cancer. A previous evaluation determined that one-third of articles published between 1970 and 1990 included women.

METHODS

To assess whether there has been an improvement in recent years, papers on occupational cancer between 1991 and 2009 were reviewed in fifteen journals.

RESULTS

The proportion of articles that included men remained stable around 90%, while the proportion of articles that included women increased substantially, from 39% in 1991-1995 to 62% in 2006-2009. Articles that assessed risk among men only or men and women presented a higher number of risk estimates and were more likely to evaluate dose-response relationships than studies including women.

CONCLUSIONS

Despite advances in the inclusion of women in studies of occupational cancer, disparities remain in the number of studies of occupational cancer and depth of analysis in studies that included women.

Cancer mortality among Brazilian dentists

BACKGROUND

Previous studies have variably shown excess risks of elected cancers among dentists.

METHODS

National Brazilian mortality data were used to obtain mortality patterns among dentists between 1996 and 2004. Cancer mortality odds ratios (MORs) and cancer proportional mortality ratios for all cancer sites were calculated, using the general population and physicians and lawyers as comparison groups.

RESULTS

Female dentists from both age strata showed higher risks for breast, colon-rectum, lung, brain, and non-Hodgkin lymphoma. Compared to physicians and lawyers, higher MOR estimates were observed for brain cancer among female dentists 20-49 yr. Among male dentists, higher cancer mortality was found for colon-rectum, pancreas, lung, melanoma, and non-Hodgkin lymphoma. Higher risk estimates for liver, prostate, bladder, brain, multiple myeloma and leukemia were observed among 50-79 yr old male dentists.

DISCUSSION

If confirmed, these results indicate the need for limiting occupational exposures among dentists in addition to establishing screening programs to achieve early detection of selected malignant tumors.

Population Attributable Risk for Occupational Gancer in Italy

Population studies estimating the proportion of cancer attributable to occupation (PAR) in different geographical areas in Italy are reviewed. Studies using lists of industrial activities and occupations which are known or suspected to entail exposure to lung carcinogens gave lung cancer PARs between 5% and 36%. Those using job-exposure matrices estimated PARs of 3%-53%, with most of the values ranging between 17 and 33%. For bladder cancer, PARs ranged between 4% and 24%. The uses and limitations of calculating population attribultable risk are discussed.

Mortality ascertainment of women veterans: a comparison of sources of vital status information, 1979-2002

BACKGROUND

To support health research on the unique cohort of women with a history of military service, this study assessed the completeness of mortality ascertainment for Texas women veterans in Department of Veterans Affairs (VA) and non-VA databases.

METHODS

We examined female veteran-specific mortality ascertainment comparing the VA Beneficiary Identification and Records Locator Subsystem Death File (BIRLS DF), VA Patient Treatment Files (PTF), and Social Security Administration-Death Master File (SSA-DMF) with Texas death certificate data. Databases were deterministically cross-linked, using female sex and social security numbers. Deterministic and probabilistic linkage methods were also compared.

RESULTS

Of 6,297 decedents identified by death certificates, SSA-DMF, BIRLS DF, and PTF databases identified 97.5% collectively and 94%, 77%, and 5% individually. Compared with Texas death certificates, sensitivity of VA and SSA databases improved with increasing age.

CONCLUSIONS

This study highlights that although the VA and SSA administrative databases have less complete ascertainment for younger decedents, combined these electronic databases provide nearly complete ascertainment for women veterans. Challenges related to large female-specific cross-linkage studies are explored, and a need to examine methods for female-specific health research studies in the general population is identified.

Do sex and site matter? Different age distribution in melanoma of the trunk among Swedish men and women

BACKGROUND

Recent research on cutaneous malignant melanoma (CMM) points to the coexistence of several biological pathways linked to the anatomical site of the lesion, which could lead to this neoplasm. Although the different anatomical distribution of CMM by sex is usually attributed to gender-specific patterns of sun exposure, it has been suggested that an alternative explanation might lie in gender-specific site susceptibility.

OBJECTIVES

This paper aimed at analysing the age distribution of CMM by site and sex to gain in-depth knowledge of differences between the sexes.

METHODS

Using a large Swedish cohort comprising 2 992 166 workers, Poisson models were fitted to estimate age-specific incidence rates by site and sex, duly adjusted for several factors that might account for changes in environmental exposures (period, birth cohort, socioeconomic level, latitude and rurality).

RESULTS

Incidence rates were 17.4 cases per 100 000 person-years in men and 16.5 in women. Sex differences were particularly striking for CMM of the trunk, where both crude and adjusted incidence rates displayed a steady increase with age in men, but reached a plateau in women at around four cases per 100 000 person-years from the 40-45-year age group (perimenopausal period) upwards. There was an almost fivefold increase in the sex ratio for this body site between the younger and older age groups, a difference which could not be attributed to period or cohort effects.

CONCLUSIONS

If different aetiological pathways can be assumed to lead to melanoma, then disparities between men and women, particularly in CMM of the trunk, suggest that a possible interaction between site and sex should be borne in mind.

Socio-economic class, rurality and risk of cutaneous melanoma by site and gender in Sweden

Background

Cutaneous melanoma (CM) is a cancer usually associated with high socio-economic level in the literature. Few studies have, however, assessed this relationship by gender and site or the association between CM and rurality.

Methods

A major-sized historical occupational Swedish cohort comprising 2,992,166 workers was used to estimate relative risk of cutaneous melanoma, broken down by gender and anatomical site, for occupational sectors (as a proxy of socio-economic class) and rurality. To this end, Poisson models were fitted for each site in men and women, including occupational sector and town size, with adjustment for age, period of diagnosis and geographical area as possible confounding factors.

Results

White collar workers presented a marked increased of risk in men in all melanoma cases, as well as in trunk, upper and lower limbs. This pattern was less clear for women, in which some heterogeneity appeared, as low risks in lower socioeconomic sectors in trunk, or risk excesses in white collar workers in lower limbs did not achieve statistical significance. Males also showed significant differences in risk by rural/urban distribution, but in women this association was limited to CM of lower limb. Risk of CM of head/neck did not vary by occupational sector or town size, thus depicting a specific epidemiological profile, which proved common to both sexes.

Conclusion

While differences in risk between men and women could suggest greater homogeneity in UV-exposure behaviour among women, the uniform risk pattern in head and neck melanoma, present in both sexes, might support the coexistence of different aetiological pathways, related to anatomical site.

Primary prevention of breast cancer by hormone-induced differentiation

Breast cancer is a fatal disease whose incidence is gradually increasing in most industrialized countries and in all ethnic groups. Primary prevention is the ultimate goal for the control of this disease. The knowledge that breast cancer risk is reduced by early full-term pregnancy and that additional pregnancies increase the rate of protection has provided novel tools for designing cancer prevention strategies. The protective effect of pregnancy has been experimentally reproduced in virgin rats by treatment with the placental hormone human chorionic gonadotropin (hCG). HCG prevents the initiation and inhibits the progression of chemically induced mammary carcinomas by inducing differentiation of the mammary gland, inhibiting cell proliferation, and increasing apoptosis. It also induces the synthesis of inhibin, a tumor suppressor factor, downregulates the level of expression of the estrogen receptor alpha (ER-alpha) by methylation of CpG islands, imprinting a permanent genomic signature that characterizes the refractory condition of the mammary gland to undergo malignant transformation. The genomic signature induced by hCG is identical to that induced by pregnancy and is specific for this hormone. Comparison of the mammary gland's genomic profile of virgin Sprague-Dawley rats treated daily with hCG for 21 days with that of rats receiving 17beta-estradiol (E2) and progesterone (Pg) (E2 + Pg) revealed that in hCG-treated rats 194 genes were significantly up-modulated (> 2.5 log2-folds) (p < 0.01) and commonly expressed, whereas these genes were not expressed in the E2 + Pg group. The genomic signature induced by hCG and pregnancy included activators or repressors of transcription genes, apoptosis, growth factors, cell division control, DNA repair, tumor suppressor, and cell-surface antigen genes. Our data indicate that hCG, like pregnancy, induces permanent genomic changes that are not reproduced by steroid hormones and in addition regulates gene expression through epigenetic mechanisms that are differentiation-dependent processes, leading us to conclude that hormonally induced differentiation offers enormous promise for the primary prevention of breast cancer.

Risk of breast cancer after night- and shift work: current evidence and ongoing studies in Denmark

Breast cancer is the most frequent cancer among women, and the number is increasing worldwide. This tumour is strongly associated with Western lifestyle, but the specific risk factors behind this observation are not well known. Exposure to light-at-night, including disturbance of the circadian rhythm, possibly mediated via the melatonin synthesis and clock genes, has been suggested as a contributing cause of breast cancer. Since shift- and night-time work is prevalent and increasing in modern societies, this exposure may be of public health concern, and contribute to the continuing elevation in breast cancer risk. Until now only few epidemiological studies have evaluated breast cancer risk after shift and night work. Although these studies are all suffering from methodological problems, especially concerning assessment of light exposure, results have consistently shown an increase in risk associated with night and shift work. Good opportunities for epidemiological cancer research exist in Denmark, and several studies on different aspects of breast cancer, work schedules, light exposure and melatonin levels are ongoing in order to further examine different aspects of this issue.

Mortality from non-malignant diseases in a cohort of female pulp and paper workers in Norway

OBJECTIVES

The objective of the present study was to investigate the risk of death from non-malignant diseases in female pulp and paper workers in Norway.

METHODS

A total of 3143 women first employed between 1920-93 were included in the study cohort. Information about each cohort member was obtained from personnel record files in the mills in order to identify employment periods and job categories. Data on cause and date of death were added by linkage to the Cause of Death Register using unique personal identification numbers. The follow up period was 1951-2000. Standardised mortality ratios (SMRs) with 95% confidence intervals (95% CIs) were calculated using the national female mortality rates as reference. Poisson regression analysis was used to examine internal relations between the duration of employment in paper departments and the risk of death from selected causes. Relative risks (RRs) and 95% CIs were calculated.

RESULTS

The study showed a significantly increased risk for total non-malignant mortality (SMR = 1.14, 95% CI 1.05 to 1.24), mainly due to increased mortality from ischaemic heart disease (SMR = 1.22, 95% CI 1.03 to 1.43) and cerebrovascular diseases (SMR = 1.16, 95% CI 0.94 to 1.42). Analysis by department showed the highest risk of death in paper department workers with short term employment. Internal analyses showed a 5% and 9% increase in risk of dying from ischaemic heart disease and respiratory diseases, respectively, among paper department workers exposed to paper dust. The risk decreased with increasing duration of employment.

CONCLUSION

The increased risk of ischaemic heart diseases and respiratory diseases seen among employees of paper departments may be related to exposure to paper dust.

Sex, gender and women's occupational health: the importance of considering mechanism

A number of researchers have pointed out that less is known about occupational determinants of health in women than in men. The authors examine inventories of ongoing Canadian research and of recent scientific publications in order to identify trends in the approaches used to study women's occupational health (WOH). We also consider conceptual issues in the treatment of the sex and gender of subjects. We observe that women have been the subject of relatively few investigations of occupational health in the natural or biomedical sciences and that studies of WOH have concentrated on the health care professions and on psychosocial stressors, with a deficit in toxicological and physiological studies. We use recent studies of mercury exposure in chloralkali process plants and of musculoskeletal disorders among office workers to provide specific examples of problems in conceptualizing WOH. We propose that WOH be studied more often, especially by researchers in the natural and biomedical sciences, and that such studies include both women and men, where possible, and consider the complex relationships of gender and sex to the pathways involved. More interdisciplinary research would facilitate this process, since social researchers have tended to focus more on gender/sex issues. Our findings demonstrate that it is necessary to explore the implications of using sex routinely as an explanatory variable in occupational health research and to increase emphasis on the mechanisms involved in any sex or gender differences sought or found. From an equity perspective, it is also important to situate biological sex differences so as to prevent them from being used erroneously to justify job segregation or inequitable health promotion measures.

Cutaneous melanoma in Swedish women: Occupational risks by anatomic site

BACKGROUND

Few occupational studies have addressed melanoma in women. Accordingly, our aim was to identify occupations with higher risk of cutaneous melanoma, overall and by site, in Swedish female workers.

METHODS

All gainfully employed Swedish women were followed-up from 1971 to 1989, using Death/Cancer Registers. Occupational risk ratios adjusted for age, period, town size, and geographic zone were computed for each site. Risk patterns for different sites were then compared.

RESULTS

High risks were observed among educators, bank tellers, dental nurses, librarians/archivists/curators, horticultural workers, and hatmakers/milliners. Telephone operators and textile workers had increased risk, mainly in the leg. Other occupation-specific site excesses were also found. Upper-limb risks were correlated with head/neck and thorax, though these two sites were not associated. Legs registered a special pattern, with a moderate correlation with upper limbs or thorax, and no correlation with head/neck.

CONCLUSIONS

Some occupations with possible exposure to arsenic/mercury displayed increased risk. The generalized excess risk among hatmakers/milliners warrants further attention. The weak correlation between legs and other sites suggests site specificity in melanoma risk factors.

Mortality in Florida professional firefighters, 1972 to 1999

BACKGROUND

Exposure to occupational hazards among firefighters may lead to increased mortality from cancer, lung, or heart disease.

METHODS

Age- and gender-adjusted mortality rates of 34,796 male and 2,017 female Florida professional firefighters between 1972 and 1999 were compared with the Florida general population.

RESULTS

One thousand four hundred eleven male and 38 female firefighter deaths with known causes were identified. In male firefighters, mortality due to all causes and most non-malignant diseases was significantly less than expected. There was no excess overall mortality from cancer, but excesses existed for male breast cancer [standardized mortality ratio (SMR = 7.41; 95% confidence interval (CI): 1.99-18.96) and thyroid cancer (SMR = 4.82; 95% CI: 1.30-12.34)]. Mortality from bladder cancer was increased and approached statistical significance (SMR = 1.79; 95% CI: 0.98-3.00). Firefighters certified between 1972 and 1976 had excess mortality from bladder cancer (SMR = 1.95; 95% CI: 1.04-3.33). Female firefighters had similar morality patterns to Florida women except for atherosclerotic heart disease (SMR = 3.85; 95% CI: 1.66-7.58).

CONCLUSIONS

Excess mortality risk from bladder cancer may be related to occupational exposure during firefighting. The thyroid cancer and breast cancer risk in males, as well as the excess risk of cardiovascular disease mortality noted in females warrant further investigation.

Physical Exposures in Work Commonly Done by Women

The North American workforce is still highly sex-segregated, with most members of each sex in jobs composed primarily of workers of the same sex. This division is accentuated when jobs involve physical demands. Women have traditionally been assigned to tasks whose physical demands are considered to be light. Nevertheless, these tasks can have biological effects, sometimes serious. Phenomena related to physical demands of women's work can be considered in three categories: (a) musculoskeletal and cardiovascular demands of tasks often assigned to women in factories and service work; (b) sex- and gender-specific effects of toxic substances found in the workplace; and (c) interactions between work and the domestic responsibilities of many women. These phenomena are described, using examples recently gathered from workplaces. Effects of biological sex are distinguished, as far as possible, from effects of gender (social roles). Keywords: ergonomics, gender, occupation, anthropometry, toxicity, repetitive movements, static effort

Occupational cancer among women: where have we been and where are we going?

Studies of occupational exposures have been a fruitful area of research for identifying carcinogens. Some of the early observations, such as increased risk of breast cancer among nuns and bone cancer among radium dial workers, were made among women. Recent research on cancer among women has shown increased risks of cancer in many industries and occupations. Estimates that 1% of cancer among women is attributable to occupation are based on research conducted mainly in the 1970s among men in developed countries. These studies do not reflect the dramatic changes in the participation of women in the workplace or the patterns of employment of women in developing countries. The proportion of women in the paid workforce, the amounts and types of unpaid labor, the distribution of women by economy sector, the scale of the workplaces, the allowable exposure levels in the workplace, and implementation of controls have changed over time and vary internationally. Occupational cancer researchers need to expand their focus on women, increase activities in developing countries, include newly created industries, use sophisticated exposure assessment methods, and, where appropriate, incorporate molecular epidemiologic techniques to discover new occupational carcinogens and to identify where better control measures are needed.

Occupational history and exposure and the risk of adult leukemia in Shanghai

PURPOSE

Evaluation of the association of selected occupational exposures with leukemia risk.

METHODS

Population-based case-control study of 486 leukemia subjects and 502 healthy controls residing in Shanghai from 1987 to 1989. Adjusted odds ratios (OR) were calculated for the association between occupational factors and leukemia risk.

RESULTS

Significant increase in leukemia risk was observed in chemical manufacturing industry workers (OR=3.1, 95% CI=1.0-9.8). Increased risks for leukemia were observed from self-reported exposures to benzene (OR=1.7, 95% CI=1.1-2.6), radioactive materials (OR=3.7, 95% CI=1.3-10.2), synthetic fiber dust (OR=2.0, 95% CI=1.2-3.5), and toluene (OR=1.6, 95% CI=1.0-2.5). Dose-response relations of leukemia risk was observed with the duration of exposure to benzene (OR=3.3, 95% CI=1.6-6.9 for >or=15 years exposure; p for trend<0.01), radioactive materials (OR=5.2, 95% CI=1.1-24.7 for >or=15 years exposure; p for trend=0.02), paints (OR=2.3, 95% CI=1.2-4.7 for >or=15 years exposure; p for trend=0.09), and toluene (OR=2.9, 95% CI=1.3-6.7 for >or=15 years exposure; p for trend=0.02).

CONCLUSIONS

Adult leukemia risk may be associated with working in the chemical industry, and exposure to benzene, synthetic fiber dust, radioactive materials, and toluene in the study population.

Be the fairest of them all: challenges and recommendations for the treatment of gender in occupational health research

BACKGROUND

Both women's and men's occupational health problems merit scientific attention. Researchers need to consider the effect of gender on how occupational health issues are experienced, expressed, defined, and addressed. More serious consideration of gender-related factors will help identify risk factors for both women and men.

METHODS

The authors, who come from a number of disciplines (ergonomics, epidemiology, public health, social medicine, community psychology, economics, sociology) pooled their critiques in order to arrive at the most common and significant problems faced by occupational health researchers who wish to consider gender appropriately.

RESULTS

This paper describes some ways that gender can be and has been handled in studies of occupational health, as well as some of the consequences. The paper also suggests specific research practices that avoid errors. Obstacles to gender-sensitive practices are considered.

CONCLUSIONS

Although gender-sensitive practices may be difficult to operationalize in some cases, they enrich the scientific quality of research and should lead to better data and ultimately to well-targeted prevention programs.

Extended mortality follow-up of a cohort of dry cleaners

PURPOSE

The mortality follow-up of a cohort of dry cleaners was extended to further evaluate cancers risks associated with organic solvents.

METHODS

The underlying and contributing causes of death among 5,369 members of a dry cleaning union in St. Louis were determined through December 31, 1993. The mortality experience of the cohort was compared to that of the US population adjusted for age at entry, year of death, race and gender.

RESULTS

The total mortality was about as expected (SMR = 1.0, N = 2351, 95% CI = 1.0-1.1). Excesses were observed for emphysema (SMR = 1.7, N = 21, 95% CI = 1.0-2.5), Hodgkin's disease (SMR = 2.0, N = 5, 95% CI = 0.6-4.6) and cancers of the esophagus (SMR = 2.2, N = 26, 95% CI = 1.5-3.3), larynx (SMR = 1.7, N = 6, 95% CI = 0.6-3.7), lung (SMR = 1.4, N = 125), 95% CI = 1.1-1.6), and cervix (SMR = 1.6, N = 27, 95% CI = 1.0-2.3). These excesses occurred among men and women and blacks and whites. Bladder cancer was elevated among white men and women and kidney cancer among black men and women, but not significantly so. None of these causes of death showed strong relationships with duration or estimated level of exposure to dry cleaning solvents, although relative risks for cancers of the larynx, lung and kidney were larger among subjects estimated to have higher levels of exposure and risks from bladder cancer and chronic nephritis were greater among persons who entered the union after 1960.

CONCLUSION

The excesses observed are unlikely to be due to chance because most occurred in earlier as well as the recent follow-up. The specific factors contributing the excesses, however, are not clear. Socioeconomic, lifestyle, and occupational exposures are all possibilities. Lack of information on socioeconomic and lifestyle factors hampers evaluation.

Cause-specific mortality among Kelly Air Force Base civilian employees, 1981-2001

In response to concerns about occupational and environmental exposures, and a perceived cluster of amyotrophic lateral sclerosis (ALS) in the community, the mortality experience among 31,811 civilian employees who worked for at least 1 year between 1981 and 2000 at Kelly Air Force Base, Texas was ascertained. A total of 3264 deaths occurred through October 31, 2001. Overall, significant deficits in mortality were observed for all causes of death and all cancers combined. An excess of breast cancer [standardized mortality ratio (SMR) = 216; 95% confidence interval (CI) = 128-341] among blue-collar women was identified, and remained elevated after adjusting for race and ethnicity [rate ratio (RR) = 2.83; 95% CI = 1.50-5.34]. Mortality from motor neuron disease, which includes ALS deaths, was not increased overall (SMR = 0.98; 95% CI = 0.52-1.68), and was lower among blue-collar employees and higher among white-collar employees than expected, based on small numbers. Overall, mortality patterns indicated a healthy worker population and no large increased mortality associated with employment at Kelly Air Force Base.