Development and Cognitive Testing of Occupational Safety and Health Questions for a Youth Survey: Addressing the Research Needs for a Vulnerable Working Population.

BACKGROUND: While more than 2.5 million U.S. high students worked in 2020, data to assess how work affects this group are sparse. To facilitate such research, a set of occupational safety and health questions for inclusion on the Youth Risk Behavior Surveillance System (YRBSS) and other youth-focused surveys was developed. METHODS: Survey questions about occupational experiences of young workers were adapted from other surveys or created de novo. Key audiences were engaged to define priority topic areas and develop draft questions, which were further refined through cognitive interviews with working youth. RESULTS: Twenty-one resulting questions spanned multiple work-related topics: employment status; health outcomes; psychosocial exposures; and safety climate. Cognitive testing revealed that youth (aged 14-19) had difficulty with temporal concepts. Some difficulties reflected the propensity of youth to engage in multiple, online, and informal jobs. During 3 rounds of interviews, questions were adjusted to better reflect youth employment circumstances and language. Four states added at least 1 work-related question to their 2023 Youth Risk Behavior Survey questionnaire, and the full set of questions has been disseminated to federal agencies and partners. CONCLUSION: Including tailored questions about employment in surveys of youth will facilitate occupational health surveillance for this group. Analysis of resulting data can help to close knowledge gaps, provide current prevalence data, inform policy, and allow development of focused prevention and intervention strategies to reduce adverse outcomes among young workers.

Assessing the role of social determinants of health in health disparities: The need for data on work.

BACKGROUND: Work is a key social determinant of health. Without the collection of work-related information in public health data systems, the role of social determinants in creating and reinforcing health disparities cannot be fully assessed. METHODS: The Centers for Disease Control and Prevention (CDC) maintains or supports a number of public health surveillance and health monitoring systems, including surveys, case-based disease and exposure systems, vital status records, and administrative data systems. We evaluated a convenience sample of these systems for inclusion of information in three work-related domains: employment status, industry and occupation, and working conditions. RESULTS: While 12 of 39 data systems were identified as collecting work-related data, this information was often minimal (e.g., only employment status), restricted to a subset of respondents, or only gathered periodically. Information on working conditions was particularly sparse. CONCLUSION: Historically, the limited and inconsistent collection of work-related information in public health data systems has hindered understanding of the role work plays in health disparities. Current CDC data modernization efforts present opportunities to enhance the identification and mitigation of health disparities by prioritizing inclusion of an expanded set of work-related data elements.

Prepandemic Mental Health and Well-being: Differences Within the Health Care Workforce and the Need for Targeted Resources.

BACKGROUND: Occupational stress and diminished well-being among health care workers were concerning even before the coronavirus disease 2019 pandemic exacerbated existing stressors and created new challenges for this workforce. Research on the mental health of health care workers has focused on physicians and nurses, with less attention to other occupations. METHODS: To assess pre-coronavirus disease mental health and well-being among workers in multiple health care occupations, we used 2017 to 2019 data from the Behavioral Risk Factor Surveillance System. RESULTS: Across the health care workforce, insufficient sleep (41.0%) and diagnosed depression (18.9%) were the most common conditions reported. Counselors had the highest prevalence of diagnosed depression. Health care support workers had elevated prevalences for most adverse health conditions. CONCLUSIONS: Ensuring a robust health care workforce necessitates identifying and implementing effective occupation-specific prevention, intervention, and mitigation strategies that address organizational and personal conditions adversely affecting mental health.

Health Care Access Among Essential Critical Infrastructure Workers, 31 States, 2017-2018.

OBJECTIVES: Essential workers in the United States need access to health care services for preventive care and for diagnosis and treatment of illnesses (coronavirus disease 2019 [COVID-19] or other infectious or chronic diseases) to remain healthy and continue working during a pandemic. This study evaluated access to health care services among selected essential workers. METHODS: We used the most recent data from the Behavioral Risk Factor Surveillance System, 2017-2018, to estimate the prevalence of 4 measures of health care access (having health insurance, being able to afford to see a doctor when needed, having a personal health care provider, and having a routine checkup in the past year) by broad and detailed occupation group among 189 208 adults aged 18-64. RESULTS: Of all occupations studied, workers in farming, fishing, and forestry occupations were most likely to have no health insurance (46.4%). Personal care aides were most likely to have been unable to see a doctor when needed because of cost (29.3%). Construction laborers were most likely to lack a personal health care provider (51.1%) and to have not had a routine physical checkup in the past year (50.6%). Compared with workers in general, workers in 3 broad occupation groups-food preparation and serving; building and grounds cleaning and maintenance; and construction trades-had significantly lower levels of health care access for all 4 measures. CONCLUSION: Lack of health insurance and underinsurance were common among subsets of essential workers. Limited access to health care might decrease essential workers' access to medical testing and needed care and hinder their ability to address underlying conditions, thereby increasing their risk of severe outcomes from some infectious diseases, such as COVID-19. Improving access to health care for all workers, including essential workers, is critical to ensure workers' health and workforce stability.

Employment status, unemployment duration, and health-related metrics among US adults of prime working age: Behavioral Risk Factor Surveillance System, 2018-2019.

BACKGROUND: While unemployment has been associated with poor health, few recent studies in the United States have comprehensively assessed associations between employment status (including duration unemployed) and healthcare access, health-related behaviors, and specific health outcomes. METHODS: We assessed health-related metrics by employment status in 2018-2019 Behavioral Risk Factor Surveillance System respondents ages 25-54. We calculated the unadjusted prevalence and adjusted prevalence ratios to compare employed workers to respondents who were self-employed, short-term (<12 months) unemployed, long-term unemployed, and unable to work. RESULTS: Adverse health outcomes increased with unemployment duration and were highest for those unable to work. Non-Hispanic Blacks were most likely to be unemployed or unable to work. Short-term unemployment and self-employment were associated with poor healthcare access. Health behaviors and outcomes declined with increasing duration of unemployment and were worst for those unable to work. CONCLUSIONS: In the United States, access to affordable healthcare is problematic for both the self-employed and the short-term unemployed. Short-term unemployment is a particularly important locus for intervention and provision of resources to prevent health declines that may hinder re-employment.

Prevalence and Predictors of Home Health Care Workers' General, Physical, and Mental Health: Findings From the 2014‒2018 Behavioral Risk Factor Surveillance System.

Objectives. To determine the prevalence and predictors of US home health care workers' (HHWs') self-reported general, physical, and mental health. Methods. Using the 2014-2018 Behavioral Risk Factor Surveillance System, we analyzed the characteristics and health of 2987 HHWs (weighted n = 659 000) compared with 2 similar low-wage worker groups (health care aides and health care support workers, not working in the home). We conducted multivariable logistic regression to determine which characteristics predicted HHWs' health. Results. Overall, 26.6% of HHWs had fair or poor general health, 14.1% had poor physical health, and 20.9% had poor mental health; the prevalence of each outcome was significantly higher than that of the comparison groups. Among HHWs, certain factors, such as low household income, an inability to see a doctor because of cost, and a history of depression, were associated with all 3 aspects of suboptimal health. Conclusions. HHWs had worse general, physical, and mental health compared with low-wage workers not in home health. Public Health Implications. Increased attention to the health of HHWs by public health experts and policymakers is warranted. In addition, targeted interventions appropriate to their specific health needs may be required. (Am J Public Health. 2021;111(12):2239-2250. https://doi.org/10.2105/AJPH.2021.306512).

Incident chronic obstructive pulmonary disease associated with occupation, industry, and workplace exposures in the Health and Retirement Study.

BACKGROUND: Chronic health effects from accumulated occupational exposures manifest as the workforce ages. The Health and Retirement Study (HRS), a panel survey of U.S. adults nearing/in retirement, allows assessment of associations among industry and occupation (I/O), workplace exposures, and incident chronic obstructive pulmonary disease (COPD). METHODS: The study population comprised respondents from the 1992 HRS cohort employed in 1972 or later and not diagnosed with COPD as of initial interview. We examined associations with incident COPD through 2016 and: (1) broad and selected detailed I/O, (2) workplace exposures, and (3) exposures within I/O. Given the cohort's baseline age (50-62), we calculated subhazard ratios (SHRs) for COPD accounting for competing risk of death. RESULTS: SHRs for COPD were significantly elevated for several industries: mining; blast furnaces, steelworks, rolling and finishing mills; groceries and related products; and automotive repair shops. Occupations with significantly elevated SHRs were maids and housemen; farmworkers; vehicle/mobile equipment mechanics and repair workers; material moving equipment operators; and nonconstruction laborers. Significantly elevated COPD SHRs were observed for specific I/O-exposure pairs: blast furnace/steelworks/rolling/finishing mills and asbestos; automotive repair shops and aerosol paints; farmworkers and pesticide exposures; and both material moving equipment operators and nonconstruction laborers exposed to dust and ash. CONCLUSIONS: Certain jobs and occupational exposures are associated with increased risk for developing COPD in late preretirement and during retirement. Given the disability and economic costs of COPD, these findings support focusing exposure prevention and medical monitoring resources on groups of workers at increased risk.

Development of Job Exposure Matrices to Estimate Occupational Exposure to Solar and Artificial Ultraviolet Radiation.

OBJECTIVES: Job exposure matrices (JEMs) are important tools for estimating occupational exposures in study populations where only information on industry and occupation (I&O) are available. JEMs The objective of this work was to create JEMs for solar and artificial ultraviolet radiation (UVR) using a US standardized coding scheme. METHODS: Using U.S. Census Bureau industry and occupation codes, separate lists of I&O pairs were developed for solar and artificial UVR by a panel of Certified Industrial Hygienists who assigned exposure ratings to I&O pairs with potential exposure. Parameters for exposure included prevalence (P) and frequency (F) for solar UVR and P, F, and intensity (I) for artificial UVR. Prevalence, or percent of all workers employed in an I&O pair who were exposed, was categorically rated: 0 to <1, 1 to <20; 20 to <80, and ≥80. Frequency of exposure, defined by the number of hours per week workers were exposed, was categorically rated: 0 to <5, 5 to <20, 20 to <35, and ≥35 h per week. For artificial UVR only, intensity of exposure was assigned three ratings: low, low with rare excursions, and >low under normal conditions. Discrepant ratings were resolved via consensus. RESULTS: After excluding I&O pairs assigned P and F ratings of 0 (solar UVR) and P, F, and I ratings of 0 (artificial UVR) from the JEM, 9206 I&O pairs were rated for solar UVR and 2010 I&O pairs for artificial UVR. For solar UVR, 723 (7.9% of all rated pairs) had ratings in the highest category for P and F; this group included 45 occupations in varied industries. Construction and extraction occupations represented most of the occupations (n = 20; 44%), followed by farming, fishing, and forestry occupations (n = 6; 13%). For artificial UVR, 87 I&O pairs (4.3% of all rated pairs) had maximum ratings for P, F, and I; these comprised a single occupation (welding, soldering, and brazing workers) in diverse industries. CONCLUSIONS: JEMs for solar and artificial UVR were developed for a broad range of I&O pairs in the US population and are available for use by researchers conducting occupational epidemiological studies.

Prevalence of Underlying Medical Conditions Among Selected Essential Critical Infrastructure Workers - Behavioral Risk Factor Surveillance System, 31 States, 2017-2018.

Certain underlying medical conditions are associated with higher risks for severe morbidity and mortality from coronavirus disease 2019 (COVID-19) (1). Prevalence of these underlying conditions among workers differs by industry and occupation. Many essential workers, who hold jobs critical to the continued function of infrastructure operations (2), have high potential for exposure to SARS-CoV-2, the virus that causes COVID-19, because their jobs require close contact with patients, the general public, or coworkers. To assess the baseline prevalence of underlying conditions among workers in six essential occupations and seven essential industries, CDC analyzed data from the 2017 and 2018 Behavioral Risk Factor Surveillance System (BRFSS) surveys, the most recent data available.* This report presents unadjusted prevalences and adjusted prevalence ratios (aPRs) for selected underlying conditions. Among workers in the home health aide occupation and the nursing home/rehabilitation industry, aPRs were significantly elevated for the largest number of conditions. Extra efforts to minimize exposure risk and prevent and treat underlying conditions are warranted to protect workers whose jobs increase their risk for exposure to SARS-CoV-2.

Differences in Safety Climate Perception by Health Care Worker, Work Schedule, and Workplace Characteristics.

Safety climate has been associated with patient and health care worker safety and outcomes. However, few studies have examined how perceptions of workplace safety differ by worker, work schedule, and workplace characteristics. Data from 10 168 participants in the National Institute for Occupational Safety and Health's Health and Safety Practices Survey of Healthcare Workers were analyzed. Multivariable regression analyses examined associations among worker and workplace characteristics and items measuring 5 areas of workplace safety perception. Safety climate perception scores were higher (more positive) for dentists and for health care workers who were salaried, were self-employed, worked day shifts and shifts ⩽11 hours, and spent <76% of their time in patient care. A wide range of health care worker, work schedule, and workplace characteristics should be considered in analyses designed to evaluate safety climate and identify potential interventions to improve downstream safety outcomes.

Codability of industry and occupation information from cancer registry records: Differences by patient demographics, casefinding source, payor, and cancer type.

INTRODUCTION: Industry and occupation (I&O) information collected by cancer registries is useful for assessing associations among jobs and malignancies. However, systematic differences in I&O availability can bias findings. METHODS: Codability by patient demographics, payor, identifying (casefinding) source, and cancer site was assessed using I&O text from first primaries diagnosed 2011-2012 and reported to California Cancer Registry. I&O were coded to a U.S. Census code or classified as blank/inadequate/unknown, retired, or not working for pay. RESULTS: Industry was codable for 37% of cases; 50% had "unknown" and 9% "retired" instead of usual industry. Cases initially reported by hospitals, covered by preferred providers, or with known occupational etiology had highest codable industry; cases from private pathology laboratories, with Medicaid, or diagnosed in outpatient settings had least. Occupation results were similar. CONCLUSIONS: Recording usual I&O for retirees and improving linkages for reporting entities without patient access would improve I&O codability and research validity.

Birth defects in infants born to employees of a microelectronics and business machine manufacturing facility.

BACKGROUND: Concerns about solvent releases from a microelectronics/business machine manufacturing facility in upstate New York led to interest in the health of former workers, including this investigation of birth defects in children of male and female employees. METHODS: Children born 1983 to 2001 to facility employees were enumerated and matched to New York State's Congenital Malformations Registry. Reported structural birth defects were compared with numbers expected from state rates (excluding New York City), generating standardized prevalence ratios (SPRs). Exposure assessors classified employees as ever/never potentially exposed at the facility to metals, chlorinated hydrocarbons, and other hydrocarbons during windows critical to organogenesis (female workers) or spermatogenesis (male workers). Among workers, adjusted prevalence ratios were generated to evaluate associations between potential exposures and specific birth defects. RESULTS: External comparisons for structural defects were at expectation for infants of male workers (SPR = 1.01; 95% confidence interval [CI], 0.77-1.29; n = 60) and lower for births to female workers (SPR = 0.84; 95% CI, 0.50-1.33; n = 18). Among full-term infants of male workers, ventricular septal defects (VSDs) were somewhat elevated compared with the general population (SPR = 1.58; 95% CI, 0.99-2.39; n = 22). Within the cohort, potential paternal metal exposure was associated with increased VSD risk (adjusted prevalence ratio = 2.70; 95% CI, = 1.09-6.67; n = 7). CONCLUSION: While overall SPRs were near expectation, paternal exposure to metals (primarily lead) appeared to be associated with increased VSD risk in infants. Take-home of occupational exposures, nonoccupational exposures, and chance could not be ruled out as causes. Case numbers for many defects were small, limiting assessment of the role of occupational exposures. Birth Defects Research (Part A) 106:696-707, 2016. © 2016 Wiley Periodicals, Inc.

Predictors of adherence to safe handling practices for antineoplastic drugs: A survey of hospital nurses.

Despite growing awareness of the hazards of exposure to antineoplastic drugs (ADs), surveys continue to find incomplete adherence to recommended safe handling guidelines. A 2011 survey of healthcare workers presents an opportunity to examine factors associated with adherence among 1094 hospital nurses who administered ADs. Data for these hypothesis-generating analyses were taken from an anonymous, web-based survey of healthcare workers. Regression modeling was used to examine associations between a number of predictors (engineering controls, work practices, nurse perceptions, and nurse and hospital characteristics) and three outcomes reported by nurses: use of personal protective equipment (PPE); activities performed with gloves previously worn to administer ADs; and spills of ADs. Adherence to safe handling guidelines was not universal, and AD spills were reported by 9.5% of nurses during the week prior to the survey. Familiarity with safe handling guidelines and training in safe handling were associated with more reported PPE use. Nurse-perceived availability of PPE was associated with more reported PPE use and lower odds of reported spills. Use of closed system drug-transfer devices and luer-lock fittings also decreased the odds of self-reported AD spills, while more frequent AD administration increased the risk. AD administration frequency was also associated with performing more activities with gloves previously worn to administer ADs, and nurse perception of having adequate time for taking safety precautions with fewer such activities. The results suggest that training and familiarity with guidelines for safe handling of ADs, adequate time to adhere to guidelines, and availability of PPE and certain engineering controls are key to ensuring adherence to safe handling practices. Further assessment of training components and engineering controls would be useful for tailoring interventions targeting these areas.

Cancer incidence and metolachlor use in the Agricultural Health Study: An update.

Metolachlor, a widely used herbicide, is classified as a Group C carcinogen by the U.S. Environmental Protection Agency based on increased liver neoplasms in female rats. Epidemiologic studies of the health effects of metolachlor have been limited. The Agricultural Health Study (AHS) is a prospective cohort study including licensed private and commercial pesticide applicators in Iowa and North Carolina enrolled 1993-1997. We evaluated cancer incidence through 2010/2011 (NC/IA) for 49,616 applicators, 53% of whom reported ever using metolachlor. We used Poisson regression to evaluate relations between two metrics of metolachlor use (lifetime days, intensity-weighted lifetime days) and cancer incidence. We saw no association between metolachlor use and incidence of all cancers combined (n = 5,701 with a 5-year lag) or most site-specific cancers. For liver cancer, in analyses restricted to exposed workers, elevations observed at higher categories of use were not statistically significant. However, trends for both lifetime and intensity-weighted lifetime days of metolachor use were positive and statistically significant with an unexposed reference group. A similar pattern was observed for follicular cell lymphoma, but no other lymphoma subtypes. An earlier suggestion of increased lung cancer risk at high levels of metolachlor use in this cohort was not confirmed in this update. This suggestion of an association between metolachlor and liver cancer among pesticide applicators is a novel finding and echoes observation of increased liver neoplasms in some animal studies. However, our findings for both liver cancer and follicular cell lymphoma warrant follow-up to better differentiate effects of metolachlor use from other factors.

Retrospective assessment of exposure to chemicals for a microelectronics and business machine manufacturing facility.

A retrospective exposure assessment was performed for use in a health outcomes study of a facility manufacturing circuit boards, business machines, and other equipment during the years 1969-2002. A matrix was developed identifying chemical use by department-year based on company-provided information. Use of six chemical agents (fiberglass, lead, methylene chloride, methyl chloroform, perchloroethylene, and trichloroethylene) and six chemical classes (acid-base, aromatic hydrocarbons, chlorinated hydrocarbons, other hydrocarbons, chlorofluorocarbons, and metals), and general (including unspecified) chemicals was identified. The matrix also contained an assignment for each department-year categorizing the potential for use of chemicals as negligible, intermittent/incidental, or routine. These department-based exposure matrix data were combined with work history data to provide duration of potential chemical use for workers. Negligible, intermittent/incidental or routine extent-of-chemical-use categories comprised 42.6%, 39.4%, and 17.9%, respectively, of total person-years of employment. Cumulative exposure scores were also developed, representing a relative measure of the cumulative extent of potential exposure to the six chemical agents, six chemical classes, and general (including unspecified) chemicals. Additionally, the study period was divided into manufacturing eras showing trends in chemical use, and showing that process use of trichloroethylene and methylene chloride ended in the mid-1980s and the mid-1990s, respectively. This approach may be useful in other assessments addressing a variety of chemicals, and with data constraints common to retrospective chemical exposure studies.

Retrospective cohort study of a microelectronics and business machine facility.

OBJECTIVES: We examined health outcomes among 34,494 workers employed at a microelectronics and business machine facility 1969-2001. METHODS: Standardized mortality ratio (SMR) and standardized incidence ratios were used to evaluate health outcomes in the cohort and Cox regression modeling to evaluate relations between scores for occupational exposures and outcomes of a priori interest. RESULTS: Just over 17% of the cohort (5,966 people) had died through 2009. All cause, all cancer, and many cause-specific SMRs showed statistically significant deficits. In hourly males, SMRs were significantly elevated for non-Hodgkin's lymphoma and rectal cancer. Salaried males had excess testicular cancer incidence. Pleural cancer and mesothelioma excesses were observed in workers hired before 1969, but no available records substantiate use of asbestos in manufacturing processes. A positive, statistically significant relation was observed between exposure scores for tetrachloroethylene and nervous system diseases. CONCLUSIONS: Few significant exposure-outcome relations were observed, but risks from occupational exposures cannot be ruled out due to data limitations and the relative youth of the cohort.

Mortality and ionising radiation exposures among workers employed at the Fernald Feed Materials Production Center (1951-1985).

OBJECTIVES: To examine mortality patterns and dose-response relations between ionising radiation and mortality outcomes of a priori interest in 6409 uranium workers employed for at least 30 days (1951-1985), and followed through 2004. METHODS: Cohort mortality was evaluated through standardised mortality ratios (SMR). Linear excess relative risk (ERR) regression models examined associations between cause-specific mortality and exposures to internal ionising radiation from uranium deposition, external gamma and x-ray radiation, and radon decay products, while adjusting for non-radiologic covariates. RESULTS: Person-years at risk totalled 236 568 (mean follow-up 37 years), and 43% of the cohort had died. All-cause mortality was below expectation only in salaried workers. Cancer mortality was significantly elevated in hourly males, primarily from excess lung cancer (SMR=1.25, 95% CI 1.09 to 1.42). Cancer mortality in salaried males was near expectation, but lymphohaematopoietic malignancies were significantly elevated (SMR=1.52, 95% CI 1.06 to 2.12). A positive dose-response relation was observed for intestinal cancer, with a significant elevation in the highest internal organ dose category and a significant dose-response with organ dose from internal uranium deposition (ERR=1.5 per 100 µGy, 95% CI 0.12 to 4.1). CONCLUSIONS: A healthy worker effect was observed only in salaried workers. Hourly workers had excess cancer mortality compared with the US population, although there was little evidence of a dose-response trend for any cancer evaluated except intestinal cancer. The association between non-malignant respiratory disease and radiation dose observed in previous studies was not apparent, possibly due to improved exposure assessment, different outcome groupings, and extended follow-up.

Update of the NIOSH life table analysis system: a person-years analysis program for the windows computing environment.

BACKGROUND: Person-years analysis is a fundamental tool of occupational epidemiology. A life table analysis system (LTAS), previously developed by the National Institute for Occupational Safety and Health, was limited by its platform and analysis and reporting capabilities. We describe the updating of LTAS for the Windows operating system (LTAS.NET) with improved properties. SOFTWARE DEVELOPMENT PROCESS: A group of epidemiologists, programmers, and statisticians developed software, platform, and computing requirements. Statistical methods include the use of (indirectly) standardized mortality ratios, (directly) standardized rate ratios, confidence intervals, and P values based on the normal approximation and exact Poisson methods, and a trend estimator for linear exposure-response associations. SOFTWARE FEATURES: We show examples using LTAS.NET to stratify and analyze multiple fixed and time-dependent variables. Data import, stratification, and reporting options are highly flexible. Users may export stratified data for Poisson regression modeling. CONCLUSIONS: LTAS.NET incorporates improvements that will facilitate more complex person-years analysis of occupational cohort data.

Occupational exposure to polychlorinated biphenyls and risk of breast cancer.

BACKGROUND: Despite the endocrine system activity exhibited by polychlorinated biphenyls (PCBs), recent studies have shown little association between PCB exposure and breast cancer mortality. OBJECTIVES: To further evaluate the relation between PCB exposure and breast cancer risk, we studied incidence, a more sensitive end point than mortality, in an occupational cohort. METHODS: We followed 5,752 women employed for at least 1 year in one of three capacitor manufacturing facilities, identifying cases from questionnaires, cancer registries, and death certificates through 1998. We collected lifestyle and reproductive information via questionnaire from participants or next of kin and used semiquantitative job-exposure matrices for inhalation and dermal exposures combined. We generated standardized incidence ratios (SIRs) and standardized rate ratios and used Cox proportional hazards regression models to evaluate potential confounders and effect modifiers. RESULTS: Overall, the breast cancer SIR was 0.81 (95% confidence interval, 0.72-0.92; n = 257), and regression modeling showed little effect of employment duration or cumulative exposure. However, for the 362 women of questionnaire-identified races other than white, we observed positive, statistically significant associations with employment duration and cumulative exposure; only smoking, birth cohort, and self- or proxy questionnaire completion had statistically significant explanatory power when added to models with exposure metrics. CONCLUSIONS: We found no overall elevation in breast cancer risk after occupational exposure to PCBs. However, the exposure-related risk elevations seen among nonwhite workers, although of limited interpretability given the small number of cases, warrant further investigation, because the usual reproductive risk factors accounted for little of the increased risk.