Last data update: Jun 17, 2024. (Total: 47034 publications since 2009)
Records 1-30 (of 38 Records) |
Query Trace: Hein MJ [original query] |
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Melanoma, thyroid cancer, and gynecologic cancers in a cohort of female flight attendants
Pinkerton LE , Hein MJ , Anderson JL , Christianson A , Little MP , Sigurdson AJ , Schubauer-Berigan MK . Am J Ind Med 2018 61 (7) 572-581 BACKGROUND: Flight attendants may have an increased risk of some cancers from occupational exposure to cosmic radiation and circadian disruption. METHODS: The incidence of thyroid, ovarian, and uterine cancer among approximately 6000 female flight attendants compared to the US population was evaluated via life table analyses. Associations of these cancers, melanoma, and cervical cancer with cumulative cosmic radiation dose and metrics of circadian disruption were evaluated using Cox regression. RESULTS: Incidence of thyroid, ovarian, and uterine cancer was not elevated. No significant, positive exposure-response relations were observed. Weak, non-significant, positive relations were observed for thyroid cancer with cosmic radiation and time zones crossed and for melanoma with another metric of circadian disruption. CONCLUSIONS: We found little evidence of increased risk of these cancers from occupational cosmic radiation or circadian disruption in female flight attendants. Limitations include few observed cases of some cancers, limited data on risk factors, and misclassification of exposures. |
Participation in a US community-based cardiovascular health study: investigating nonrandom selection effects related to employment, perceived stress, work-related stress, and family caregiving
MacDonald LA , Fujishiro K , Howard VJ , Landsbergis P , Hein MJ . Ann Epidemiol 2017 27 (9) 545-552 e2 PURPOSE: Participation in health studies may be inversely associated with employment and stress. We investigated whether employment, perceived stress, work-related stress, and family caregiving were related to participation in a longitudinal US community-based health study of black and white men and women aged ≥45 years. METHODS: Prevalence ratios and confidence intervals were estimated for completion of the second stage (S2) of a two-stage enrollment process by employment (status, type), and stress (perceived stress, work-related stress, caregiving), adjusting for age, sex, race, region, income, and education. Eligibility and consent for a follow-up occupational survey were similarly evaluated. RESULTS: Wage- but not self-employed participants were less likely than the unemployed to complete S2. Among the employed, S2 completion did not vary by stress; however, family caregivers with a short time burden of care (<2 hour/d) were more likely to complete S2, compared to noncaregivers. Eligibility and participation in the follow-up occupational survey were higher among those employed (vs. unemployed) at enrollment but were not associated with enrollment stress levels. CONCLUSIONS: Limited evidence of selection bias was seen by employment and stress within a large US community-based cohort, but findings suggest the need for enrollment procedures to consider possible barriers to participation among wage-employed individuals. |
Prevalence of cardiovascular health by occupation: A cross-sectional analysis among U.S. workers aged ≥45 years
MacDonald LA , Bertke S , Hein MJ , Judd S , Baron S , Merritt R , Howard VJ . Am J Prev Med 2017 53 (2) 152-161 INTRODUCTION: Identification of groups with poor cardiovascular health (CVH) can inform where and how to target public health efforts. National prevalence estimates of CVH were derived for clinical (blood glucose, total cholesterol, blood pressure) and behavioral (BMI, diet quality, physical activity, smoking) factors among U.S. workers aged ≥45 years. METHODS: This cross-sectional analysis included 6,282 employed black and white men and women aged ≥45 years enrolled in the national population-based REasons for Geographic And Racial Differences in Stroke study from 2003 to 2007. Each CVH factor was scored as ideal (2); intermediate (1); or poor (0) according to American Heart Association criteria, and summed to define optimal composite scores: CVH (sum, 10-14); clinical (sum, 5-6); and behavioral (sum, 6-8) health. Occupational data were collected 2011-2013. Analyses were conducted in 2016. RESULTS: Only 14% met ideal criteria for all three clinical health factors, and none met ideal criteria for all four behavioral health factors. Sales and low status office workers had a low prevalence of optimal CVH. Service workers in protective services and the food preparation and serving occupations had a low prevalence of optimal clinical health; computer and healthcare support workers had a low prevalence of optimal behavioral health. CONCLUSIONS: The prevalence of optimal CVH among middle-aged and older workers in the U.S. is low, but considerable differences exist by occupation. Targeted public health interventions may improve the CVH of at-risk older workers with different clinical and behavioral risk factor profiles employed in diverse occupational settings. |
Agreement between two methods for retrospective assessment of occupational exposure intensity to six chlorinated solvents: Data from The National Birth Defects Prevention Study
Johnson CY , Rocheleau CM , Hein MJ , Waters MA , Stewart PA , Lawson CC , Reefhuis J . J Occup Environ Hyg 2017 14 (5) 389-396 The wide variety of jobs encountered in population-based studies makes retrospective exposure assessment challenging in occupational epidemiology. In this analysis, two methods for estimating exposure intensity to chlorinated solvents are compared: rated (assigned by an expert rater) and modeled (assigned using statistical models). Estimates of rated and modeled intensities were compared for jobs held by mothers participating in the National Birth Defects Prevention Study with possible exposure to six chlorinated solvents: carbon tetrachloride, chloroform, methylene chloride, perchloroethylene, 1,1,1-trichloroethane, and trichloroethylene. For each possibly exposed job, an industrial hygienist assigned (1) an exposure intensity (rated intensity) and (2) determinants of exposure to be used in a statistical model of exposure intensity (modeled intensity). Of 12,326 reported jobs, between 31 (0.3%) and 746 (6%) jobs were rated as possibly exposed to each of the six solvents. Agreement between rated and modeled intensities was low overall (Spearman correlation coefficient range: -0.09 to 0.28; kappa range: -0.23 to 0.43). Although no air measurements were available to determine if rated or modeled estimates were more accurate, review of participants' job titles showed that modeled estimates were often unexpectedly high given the low-exposure tasks found in these jobs. Differences between the high-exposure jobs used to create the statistical models (obtained from air measurements in the published literature) and the low-exposure jobs in the actual study population is a potential explanation for the disagreement between the two methods. Investigators should be aware that statistical models estimating exposure intensity using existing data from one type of worker population might not be generalizable to all populations of workers. |
Cancer incidence among capacitor manufacturing workers exposed to polychlorinated biphenyls
Ruder AM , Hein MJ , Hopf NB , Waters MA . Am J Ind Med 2017 60 (2) 198-207 BACKGROUND: We evaluated cancer incidence in a cohort of polychlorinated biphenyl (PCB) exposed workers. METHODS: Incident cancers, identified using state registries, were compared to those in a national population using standardized incidence ratios. Trends in prostate cancer incidence with cumulative PCB exposure were evaluated using standardized rate ratios and Cox regression models. For selected sites, cumulative PCB exposure was compared between aggressive (fatal/distant stage) and localized/regional cancers. RESULTS: We identified 3,371 invasive first primary cancer diagnoses among 21,317 eligible workers through 2007. Overall relative incidence was reduced. Elevations were only observed for respiratory cancers and among women, urinary organ cancers. Among men, prostate cancer incidence was reduced and not associated with cumulative PCB exposure although median exposures were significantly higher for aggressive compared to localized/regional prostate cancers. CONCLUSION: Previously observed associations between cumulative PCB exposure and prostate cancer mortality were not confirmed in this analysis; prostate cancer stage at diagnosis may explain the discrepancy. |
Occupational exposure to chlorinated solvents and kidney cancer: a case-control study
Purdue MP , Stewart PA , Friesen MC , Colt JS , Locke SJ , Hein MJ , Waters MA , Graubard BI , Davis F , Ruterbusch J , Schwartz K , Chow WH , Rothman N , Hofmann JN . Occup Environ Med 2016 74 (4) 268-274 OBJECTIVES: Trichloroethylene, a chlorinated solvent widely used for metal degreasing, is classified by the International Agency for Research on Cancer as a kidney carcinogen. Other chlorinated solvents are suspected carcinogens, most notably the cleaning solvent perchloroethylene, although it is unclear whether they are associated with kidney cancer. We investigated kidney cancer associations with occupational exposure to 6 chlorinated solvents (trichloroethylene, perchloroethylene, 1,1,1-trichloroethane, carbon tetrachloride, chloroform, and methylene chloride) within a case-control study using detailed exposure assessment methods. METHODS: Cases (n=1217) and controls (n=1235) provided information on their occupational histories and, for selected occupations, on tasks involving potential exposure to chlorinated solvents through job-specific interview modules. Using this information, an industrial hygienist assessed potential exposure to each solvent. We computed ORs and 95% CIs for different exposure metrics, with unexposed participants as the referent group. RESULTS: 1,1,1-trichloroethane, carbon tetrachloride, chloroform, and methylene chloride were not associated with kidney cancer. Among jobs with high exposure intensity, high cumulative hours exposed to perchloroethylene was associated with increased risk, both overall (third tertile vs unexposed: OR 3.1, 95% CI 1.3 to 7.4) and after excluding participants with ≥50% exposure probability for trichloroethylene (OR 3.0, 95% CI 0.99 to 9.0). A non-significant association with high cumulative hours exposed to trichloroethylene was observed (OR 1.7, 95% CI 0.8 to 3.8). CONCLUSIONS: In this study, high exposure to perchloroethylene was associated with kidney cancer, independent of trichloroethylene. Additional studies are needed to further investigate this finding. |
Breast cancer incidence among female flight attendants: Exposure-response analyses
Pinkerton LE , Hein MJ , Anderson JL , Little MP , Sigurdson AJ , Schubauer-Berigan MK . Scand J Work Environ Health 2016 42 (6) 538-546 OBJECTIVE: The aim of this study was to examine the association of breast cancer incidence with cosmic radiation dose and circadian rhythm disruption in a cohort of 6093 US female flight attendants. METHODS: The association of breast cancer risk with cumulative cosmic radiation dose, time spent working during the standard sleep interval, and time zones crossed (all lagged by ten years), adjusted for non-occupational breast cancer risk factors, was evaluated using Cox regression. Individual exposure estimates were derived from work history data and domicile- and era-specific exposure estimates. Breast cancers were identified from telephone interviews and state cancer registries, and covariate data were obtained from telephone interviews. RESULTS: Breast cancer incidence in the overall cohort was not associated with exposure. Positive associations in breast cancer incidence were observed with all three exposures only among the 884 women with parity of ≥3. Adjusted excess relative risks for women with parity of ≥3 were 1.6 [95% confidence interval (95% CI) 0.14-6.6], 0.99 (95% CI -0.04-4.3), and 1.5 (95% CI 0.14-6.2) per 10 mGy, per 2000 hours spent working in the standard sleep interval, and per 4600 time zones crossed (the approximate means of the fourth exposure quintiles among breast cancer cases), respectively. CONCLUSIONS: Positive exposure-response relations, although observed only in a small subset of the cohort, were robust. Future studies of breast cancer incidence among other workers with circadian rhythm disruption should assess interaction with parity to see if our findings are confirmed. |
Mortality of lead smelter workers: A follow-up study with exposure assessment
Bertke SJ , Lehman EJ , Wurzelbacher SJ , Hein MJ . Am J Ind Med 2016 59 (11) 979-986 BACKGROUND: Lead exposure has been linked to impaired renal function and kidney failure. High lead exposures have been associated with increased mortality from certain cancers, hypertension, cardiovascular disease, and amyotrophic lateral sclerosis (ALS). METHODS: We extended vital status follow-up on a cohort of 1,990 lead smelter workers by 25 years and computed standardized mortality ratios and rate ratios (RR) stratified by cumulative lead exposure. RESULTS: The update added 13,823 person-years at risk and 721 deaths. Increased risk of mortality was observed for the a priori outcomes of lung cancer, cardiovascular disease (including cerebrovascular disease), chronic kidney disease, and ALS. However, of these outcomes, only cardiovascular, cerebrovascular, and chronic kidney diseases were associated with a positive exposure-response in RR analyses. CONCLUSIONS: This study reaffirms the association of lead exposure with cardiovascular and kidney diseases; however, increased mortality observed for certain cancers is not likely to be due to lead exposure. Am. J. Ind. Med. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. |
Mortality from neurodegenerative diseases in a cohort of US flight attendants
Pinkerton LE , Hein MJ , Grajewski B , Kamel F . Am J Ind Med 2016 59 (7) 532-7 BACKGROUND: Concern exists about the potential chronic neurological effects among aircrew of exposure to chemical contaminants from engine oil in aircraft cabin air. We evaluated mortality from neurodegenerative diseases among 11,311 former US flight attendants. METHODS: Vital status was ascertained through 2007, and life table analyses were conducted to obtain standardized mortality ratios (SMRs). RESULTS: Amyotrophic lateral sclerosis (ALS) mortality was over twice as high in the cohort as in the US general population, based on nine observed ALS deaths. There was no clear pattern in risk when SMRs for ALS were stratified by exposure duration. Mortality from other neurodegenerative diseases was not elevated. CONCLUSIONS: Our findings are limited due to small numbers of observed deaths and reliance on mortality data, but suggest that flight attendants may have an increased risk of ALS. Additional research is needed. |
Suicide mortality among retired national football league players who played 5 or more seasons
Lehman EJ , Hein MJ , Gersic CM . Am J Sports Med 2016 44 (10) 2486-2491 BACKGROUND: There is current disagreement in the scientific literature about the relationship between playing football and suicide risk, particularly among professional players in the National Football League (NFL). While some research indicates players are at high risk of football-related concussions, which may lead to chronic traumatic encephalopathy and suicide, other research finds such a connection to be speculative and unsupported by methodologically sound research. PURPOSE: To compare the suicide mortality of a cohort of NFL players to what would be expected in the general population of the United States. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A cohort of 3439 NFL players with at least 5 credited playing seasons between 1959 and 1988 was assembled for statistical analysis. The vital status for this cohort was updated through 2013. Standardized mortality ratios (SMRs), the ratio of observed deaths to expected deaths, and 95% CIs were computed for the cohort; 95% CIs that excluded unity were considered statistically significant. For internal comparison purposes, standardized rate ratios were calculated to compare mortality results between players stratified into speed and nonspeed position types. RESULTS: Suicide among this cohort of professional football players was significantly less than would be expected in comparison with the United States population (SMR = 0.47; 95% CI, 0.24-0.82). There were no significant differences in suicide mortality between speed and nonspeed position players. CONCLUSION: There is no indication of elevated suicide risk in this cohort of professional football players with 5 or more credited seasons of play. Because of the unique nature of this cohort, these study results may not be applicable to professional football players who played fewer than 5 years or to college or high school players. |
Re: Bias in the proportionate mortality ratio analysis of small study populations: A case on analyses of radiation and mesothelioma
Hein MJ , Schubauer-Berigan MK . Int J Radiat Biol 2015 91 (11) 908-10 Studies of mortality in occupational groups frequently use proportionate mortality ratio (PMR) analyses (Steenland et al.Citation1990). In the simplest case, the PMR is the ratio of the proportion of deaths due to a specific cause in the study population to the proportion of deaths due to the same cause in a referent population. Software packages such as the NIOSH Life-Table Analysis System (LTAS.NET) can estimate PMRs that are adjusted for gender, race, age, and calendar year (Schubauer-Berigan et al. Citation2011). Zhou (Citation2014) recently claimed that the PMR reported in the NIOSH LTAS.NET program is biased under certain conditions - namely, when the number of deaths available for analysis is small relative to the number of cause-of-death categories, resulting in categories with zero observed deaths. To remove the bias, Zhou proposed an adjustment that involved excluding deaths from the referent population for categories with zero deaths in the sample when estimating the PMR. The objective of this letter is to point out faulty logic in Zhou's proposed adjustment and assure users of LTAS.NET that the PMR estimates produced by LTAS.NET are not biased. |
Breast cancer incidence in a cohort of U.S. flight attendants
Schubauer-Berigan MK , Anderson JL , Hein MJ , Little MP , Sigurdson AJ , Pinkerton LE . Am J Ind Med 2015 58 (3) 252-66 BACKGROUND: Flight attendants may have elevated breast cancer incidence (BCI). We evaluated BCI's association with cosmic radiation dose and circadian rhythm disruption among 6,093 female former U.S. flight attendants. METHODS: We collected questionnaire data on BCI and risk factors for breast cancer from 2002-2005. We conducted analyses to evaluate (i) BCI in the cohort compared to the U.S. population; and (ii) exposure-response relations. We applied an indirect adjustment to estimate whether parity and age at first birth (AFB) differences between the cohort and U.S. population could explain BCI that differed from expectation. RESULTS: BCI was elevated but may be explained by lower parity and older AFB in the cohort than among U.S. women. BCI was not associated with exposure metrics in the cohort overall. Significant positive associations with both were observed only among women with parity of three or more. CONCLUSIONS: Future cohort analyses may be informative on the role of these occupational exposures and non-occupational risk factors. |
Miscarriage among flight attendants
Grajewski B , Whelan EA , Lawson CC , Hein MJ , Waters MA , Anderson JL , MacDonald LA , Mertens CJ , Tseng CY , Cassinelli RT 2nd , Luo L . Epidemiology 2015 26 (2) 192-203 BACKGROUND: Cosmic radiation and circadian disruption are potential reproductive hazards for flight attendants. METHODS: Flight attendants from 3 US airlines in 3 cities were interviewed for pregnancy histories and lifestyle, medical, and occupational covariates. We assessed cosmic radiation and circadian disruption from company records of 2 million individual flights. Using Cox regression models, we compared respondents (1) by levels of flight exposures and (2) to teachers from the same cities, to evaluate whether these exposures were associated with miscarriage. RESULTS: Of 2654 women interviewed (2273 flight attendants and 381 teachers), 958 pregnancies among 764 women met study criteria. A hypothetical pregnant flight attendant with median first-trimester exposures flew 130 hours in 53 flight segments, crossed 34 time zones, and flew 15 hours during her home-base sleep hours (10 pm-8 am), incurring 0.13 mGy absorbed dose (0.36 mSv effective dose) of cosmic radiation. About 2% of flight attendant pregnancies were likely exposed to a solar particle event, but doses varied widely. Analyses suggested that cosmic radiation exposure of 0.1 mGy or more may be associated with increased risk of miscarriage in weeks 9-13 (odds ratio = 1.7 [95% confidence interval = 0.95-3.2]). Risk of a first-trimester miscarriage with 15 hours or more of flying during home-base sleep hours was increased (1.5 [1.1-2.2]), as was risk with high physical job demands (2.5 [1.5-4.2]). Miscarriage risk was not increased among flight attendants compared with teachers. CONCLUSIONS: Miscarriage was associated with flight attendant work during sleep hours and high physical job demands and may be associated with cosmic radiation exposure. |
Methods and feasibility of collecting occupational data for a large population-based cohort study in the United States: the reasons for geographic and racial differences in stroke study
MacDonald LA , Pulley L , Hein MJ , Howard VJ . BMC Public Health 2014 14 (1) 142 BACKGROUND: Coronary heart disease and stroke are major contributors to preventable mortality. Evidence links work conditions to these diseases; however, occupational data are perceived to be difficult to collect for large population-based cohorts. We report methodological details and the feasibility of conducting an occupational ancillary study for a large U.S. prospective cohort being followed longitudinally for cardiovascular disease and stroke. METHODS: Current and historical occupational information were collected from active participants of the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study. A survey was designed to gather quality occupational data among this national cohort of black and white men and women aged 45 years and older (enrolled 2003-2007). Trained staff conducted Computer-Assisted Telephone Interviews (CATI). After a brief pilot period, interviewers received additional training in the collection of narrative industry and occupation data before administering the survey to remaining cohort members. Trained coders used a computer-assisted coding system to assign U.S. Census codes for industry and occupation. All data were double coded; discrepant codes were independently resolved. RESULTS: Over a 2-year period, 17,648 participants provided consent and completed the occupational survey (87% response rate). A total of 20,427 jobs were assigned Census codes. Inter-rater reliability was 80% for industry and 74% for occupation. Less than 0.5% of the industry and occupation data were uncodable, compared with 12% during the pilot period. Concordance between the current and longest-held jobs was moderately high. The median time to collect employment status plus narrative and descriptive job information by CATI was 1.6 to 2.3 minutes per job. Median time to assign Census codes was 1.3 minutes per rater. CONCLUSIONS: The feasibility of conducting high-quality occupational data collection and coding for a large heterogeneous population-based sample was demonstrated. We found that training for interview staff was important in ensuring that narrative responses for industry and occupation were adequately specified for coding. Estimates of survey administration time and coding from digital records provide an objective basis for planning future studies. The social and environmental conditions of work are important understudied risk factors that can be feasibly integrated into large population-based health studies. |
Coronary artery disease and cancer mortality in a cohort of workers exposed to vinyl chloride, carbon disulfide, rotating shift work, and o-toluidine at a chemical manufacturing plant
Carreon T , Hein MJ , Hanley KW , Viet SM , Ruder AM . Am J Ind Med 2014 57 (4) 398-411 BACKGROUND: We updated through 2007 the mortality experience of 1,874 workers employed at a New York State chemical manufacturing plant between 1946 and 2006. METHODS: Reassessed exposures to vinyl chloride, carbon disulfide, and shift work and categories of o-toluidine exposure were based on year, department and job title. Standardized mortality ratios (SMR) compared mortality to that of the US population. Internal comparisons used directly standardized rate ratios. RESULTS: Hepatobiliary cancer mortality was elevated among workers ever exposed to vinyl chloride (SMR = 3.80, 95% confidence interval 1.89-6.80); directly standardized rates increased with increasing vinyl chloride exposure duration. No increase in non-Hodgkin lymphoma mortality was observed with vinyl chloride and shift work exposures. Internal comparisons showed increased coronary artery disease mortality among long-term workers exposed to carbon disulfide and shift work for 4 years or more. CONCLUSIONS: Excess coronary artery disease mortality confirms earlier results; further investigation is needed to understand risk factors. |
Bladder cancer incidence among workers exposed to o-toluidine, aniline and nitrobenzene at a rubber chemical manufacturing plant
Carreon T , Hein MJ , Hanley KW , Viet SM , Ruder AM . Occup Environ Med 2013 71 (3) 175-82 BACKGROUND: An earlier investigation found increased bladder cancer incidence among workers at a rubber chemical manufacturing plant that used o-toluidine, aniline and nitrobenzene. The cohort was expanded to include additional workers (n=1875) and updated through 2007 to assess bladder cancer with improved exposure characterisation. METHODS: Work histories were updated and exposure categories and ranks were developed for o-toluidine, aniline and nitrobenzene combined. Incident cancers were identified by linkage to six state cancer registries. Residency in time-dependent cancer registry catchment areas was determined. SIR and standardised rate ratios for bladder cancer were calculated by exposure category and cumulative rank quartiles for different lag periods. Cox regression was used to model bladder cancer incidence with estimated cumulative rank, adjusting for confounders. Indirect methods were used to control for smoking. RESULTS: Excess bladder cancer was observed compared to the New York State population (SIR=2.87, 95% CI 2.02 to 3.96), with higher elevations among workers definitely exposed (moderate/high) (SIR=3.90, 95% CI 2.57 to 5.68), and in the highest cumulative rank quartile (SIR=6.13, 95% CI 2.80 to 11.6, 10-year lag). Bladder cancer rates increased significantly with estimated cumulative rank (10-year lag). Smoking only accounted for an estimated 8% elevation in bladder cancer incidence. CONCLUSIONS: Bladder cancer incidence remains elevated in this cohort and significantly associated with estimated cumulative exposure. Results are consistent with earlier findings in this and other cohorts. Despite other concurrent chemical exposures, we consider o-toluidine most likely responsible for the bladder cancer incidence elevation and recommend a re-examination of occupational exposure limits. |
Cohort mortality study of garment industry workers exposed to formaldehyde: update and internal comparisons
Meyers AR , Pinkerton LE , Hein MJ . Am J Ind Med 2013 56 (9) 1027-39 BACKGROUND: To further evaluate the association between formaldehyde and leukemia, we extended follow-up through 2008 for a cohort mortality study of 11,043 US formaldehyde-exposed garment workers. METHODS: We computed standardized mortality ratios and standardized rate ratios stratified by year of first exposure, exposure duration, and time since first exposure. Associations between exposure duration and rates of leukemia and myeloid leukemia were further examined using Poisson regression models. RESULTS: Compared to the US population, myeloid leukemia mortality was elevated but overall leukemia mortality was not. In internal analyses, overall leukemia mortality increased with increasing exposure duration and this trend was statistically significant. CONCLUSIONS: We continue to see limited evidence of an association between formaldehyde and leukemia. However, the extended follow-up did not strengthen previously observed associations. In addition to continued epidemiologic research, we recommend further research to evaluate the biological plausibility of a causal relation between formaldehyde and leukemia. |
Mortality among 24,865 workers exposed to polychlorinated biphenyls (PCBs) in three electrical capacitor manufacturing plants: a ten-year update
Ruder AM , Hein MJ , Hopf NB , Waters MA . Int J Hyg Environ Health 2013 217 176-87 The objective of this analysis was to evaluate mortality among a cohort of 24,865 capacitor-manufacturing workers exposed to polychlorinated biphenyls (PCBs) at plants in Indiana, Massachusetts, and New York and followed for mortality through 2008. Cumulative PCB exposure was estimated using plant-specific job-exposure matrices. External comparisons to US and state-specific populations used standardized mortality ratios, adjusted for gender, race, age and calendar year. Among long-term workers employed 3 months or longer, within-cohort comparisons used standardized rate ratios and multivariable Poisson regression modeling. Through 2008, more than one million person-years at risk and 8749 deaths were accrued. Among long-term employees, all-cause and all-cancer mortality were not elevated; of the a priori outcomes assessed only melanoma mortality was elevated. Mortality was elevated for some outcomes of a priori interest among subgroups of long-term workers: all cancer, intestinal cancer and amyotrophic lateral sclerosis (women); melanoma (men); melanoma and brain and nervous system cancer (Indiana plant); and melanoma and multiple myeloma (New York plant). Standardized rates of stomach and uterine cancer and multiple myeloma mortality increased with estimated cumulative PCB exposure. Poisson regression modeling showed significant associations with estimated cumulative PCB exposure for prostate and stomach cancer mortality. For other outcomes of a priori interest - rectal, liver, ovarian, breast, and thyroid cancer, non-Hodgkin lymphoma, Alzheimer disease, and Parkinson disease - neither elevated mortality nor positive associations with PCB exposure were observed. Associations between estimated cumulative PCB exposure and stomach, uterine, and prostate cancer and myeloma mortality confirmed our previous positive findings. |
Assessment of ALS mortality in a cohort of formaldehyde-exposed garment workers
Pinkerton LE , Hein MJ , Meyers A , Kamel F . Amyotroph Lateral Scler Frontotemporal Degener 2013 14 353-5 The etiology of ALS is unknown. Although some investigators have evaluated the role of occupational exposures (1), their role is poorly understood. | Among subjects with known exposure duration in the American Cancer Society’s Cancer Prevention Study II cohort (~1 million subjects), the ALS mortality rate was more than two times higher for subjects with self-reported formaldehyde exposure, compared to unexposed subjects (rate ratio 2.47, 95% confidence interval (CI) 1.58-3.86, 1120 unexposed and 22 exposed cases), and strongly associated with exposure duration (2). Compared to unexposed subjects, the rate ratios were 1.5, 2.1, and 4.1 for subjects with < 4, 4–10, and > 10 years of self-reported formaldehyde exposure, respectively. In contrast, formaldehyde exposure (inferred from occupation) was not associated with ALS in a small case-control study (109 cases, 253 controls) by Fang and colleagues (1). In this study, no association was observed with weighted exposure duration although an imprecise 3-fold increase of ALS, based on four cases, was observed among a sub-group of the highest exposure tertile. | We evaluated ALS mortality among a cohort of formaldehyde-exposed garment workers (3–5). |
Mortality and ionising radiation exposures among workers employed at the Fernald Feed Materials Production Center (1951-1985)
Silver SR , Bertke SJ , Hein MJ , Daniels RD , Fleming DA , Anderson JL , Pinney SM , Hornung RW , Tseng CY . Occup Environ Med 2013 70 (7) 453-63 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 muGy, 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. |
The Upper Midwest Health Study: gliomas and occupational exposure to chlorinated solvents
Ruder AM , Yiin JH , Waters MA , Carreon T , Hein MJ , Butler MA , Calvert GM , Davis-King KE , Schulte PA , Mandel JS , Morton RF , Reding DJ , Rosenman KD , Stewart PA . Occup Environ Med 2012 70 (2) 73-80 ![]() OBJECTIVES: Occupational exposure to chlorinated aliphatic solvents has been associated with an increased cancer risk, including brain cancer. However, many of these solvents remain in active, large-volume use. We evaluated glioma risk from non-farm occupational exposure (ever/never and estimated cumulative exposure) to any of the six chlorinated solvents-carbon tetrachloride, chloroform, methylene chloride, trichloroethylene, tetrachloroethylene or 1,1,1-trichloroethane-among 798 cases and 1175 population-based controls, aged 18-80 years and non-metropolitan residents of Iowa, Michigan, Minnesota and Wisconsin. METHODS: Solvent use was estimated based on occupation, industry and era, using a bibliographic database of published exposure levels and exposure determinants. Unconditional logistic regression was used to calculate ORs adjusted for frequency matching variables age group and sex, and age and education. Additional analyses were limited to 904 participants who donated blood specimens (excluding controls reporting a previous diagnosis of cancer) genotyped for glutathione-S-transferases GSTP1, GSTM3 and GSTT1. Individuals with functional GST genes might convert chlorinated solvents crossing the blood-brain barrier into cytotoxic metabolites. RESULTS: Both estimated cumulative exposure (ppm-years) and ever exposure to chlorinated solvents were associated with decreased glioma risk and were statistically significant overall and for women. In analyses comparing participants with a high probability of exposure with the unexposed, no associations were statistically significant. Solvent-exposed participants with functional GST genes were not at increased risk of glioma. CONCLUSIONS: We observed no associations of glioma risk and chlorinated solvent exposure. Large pooled studies are needed to explore the interaction of genetic pathways and environmental and occupational exposures in glioma aetiology. |
Neurodegenerative causes of death among retired National Football League players
Lehman EJ , Hein MJ , Baron SL , Gersic CN . Neurology 2012 79 (19) 1970-4 OBJECTIVE: To analyze neurodegenerative causes of death, specifically Alzheimer disease (AD), Parkinson disease, and amyotrophic lateral sclerosis (ALS), among a cohort of professional football players. METHODS: This was a cohort mortality study of 3,439 National Football League players with at least 5 pension-credited playing seasons from 1959 to 1988. Vital status was ascertained through 2007. For analysis purposes, players were placed into 2 strata based on characteristics of position played: nonspeed players (linemen) and speed players (all other positions except punter/kicker). External comparisons with the US population used standardized mortality ratios (SMRs); internal comparisons between speed and nonspeed player positions used standardized rate ratios (SRRs). RESULTS: Overall player mortality compared with that of the US population was reduced (SMR 0.53, 95% confidence interval [CI] 0.48-0.59). Neurodegenerative mortality was increased using both underlying cause of death rate files (SMR 2.83, 95% CI 1.36-5.21) and multiple cause of death (MCOD) rate files (SMR 3.26, 95% CI 1.90-5.22). Of the neurodegenerative causes, results were elevated (using MCOD rates) for both ALS (SMR 4.31, 95% CI 1.73-8.87) and AD (SMR 3.86, 95% CI 1.55-7.95). In internal analysis (using MCOD rates), higher neurodegenerative mortality was observed among players in speed positions compared with players in nonspeed positions (SRR 3.29, 95% CI 0.92-11.7). CONCLUSIONS: The neurodegenerative mortality of this cohort is 3 times higher than that of the general US population; that for 2 of the major neurodegenerative subcategories, AD and ALS, is 4 times higher. These results are consistent with recent studies that suggest an increased risk of neurodegenerative disease among football players. (Neurology 2012;79:1-1) |
Occupational exposure to chlorinated solvents and risks of glioma and meningioma in adults
Neta G , Stewart PA , Rajaraman P , Hein MJ , Waters MA , Purdue MP , Samanic C , Coble JB , Linet MS , Inskip PD . Occup Environ Med 2012 69 (11) 793-801 ![]() OBJECTIVES: Chlorinated solvents are classified as probable or possible carcinogens. It is unknown whether exposure to these agents increases the risk of malignant or benign brain tumours. Our objective was to evaluate associations of brain tumour risk with occupational exposure to six chlorinated solvents (ie, dichloromethane, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene and perchloroethylene). METHODS: 489 glioma cases, 197 meningioma cases and 799 controls were enrolled in a hospital-based case-control study conducted at three USA hospitals in Arizona, Massachusetts and Pennsylvania. Information about occupational history was obtained through a detailed inperson interview that included job-specific modules of questions such that the interview was tailored to each individual's particular work history. An industrial hygienist assessed potential solvent exposure based on this information and an exhaustive review of the relevant industrial hygiene literature. Unconditional logistic regression models were used to calculate OR and 95% CI for each solvent for ever/never, duration, cumulative, average weekly and highest exposure. RESULTS: Overall, we found no consistent evidence of an increased risk of glioma or meningioma related to occupational exposure to the six chlorinated solvents evaluated. There was some suggestion of an association between carbon tetrachloride and glioma in analyses restricted to exposed subjects, with average weekly exposure above the median associated with increased risk compared with below the median exposure (OR = 7.1, 95% CI 1.1 to 45.2). CONCLUSIONS: We found no consistent evidence for increased brain tumour risk related to chlorinated solvents. |
Exposure to o-toluidine, aniline, and nitrobenzene in a rubber chemical manufacturing plant: a retrospective exposure assessment update
Hanley KW , Viet SM , Hein MJ , Carreon T , Ruder AM . J Occup Environ Hyg 2012 9 (8) 478-90 The National Institute for Occupational Safety and Health previously conducted a retrospective cancer incidence and mortality study of workers employed at a rubber chemical manufacturing plant. Compared with New York State incidence, the bladder cancer risk was 6.5 times higher for workers considered to have definite exposure to ortho-toluidine and aniline, and 4 times higher for workers with possible exposure. Exposure characterization in the original study utilized a surrogate measure based only on departments in which each worker was ever employed. As part of an update of that study, some departments in the three original exposure groups were reclassified based on a follow-up site visit; interviews with employees, management, and union representatives; and review of records including exposure data. An additional evaluation of department-job combinations, rather than only departments, was used to stratify exposure into four categories. An approximate rank of "relative" exposure level for each department-job-year combination was also assigned using a ranking scale of 0 to 10. The ranks were supported by quantitative exposure levels and by professional judgment. The numerical ranking scale was applied to each worker by multiplying the exposure rank by duration for each job held based on comprehensive individual work histories. The cumulative rank scores for this cohort ranged from 0 to 300 unit-years. The medians of the cumulative rank scores for the exposure categories showed very good agreement with increasing exposure classifications (e.g., 0.72, 4.6, 11, 14 unit-years for the four exposure categories). Workers' breathing zone air sampling data collected at this plant from 1976-2004 were well below published occupational exposure limits for these chemicals, but additional cases of bladder cancer have been reported. The exposure assessment revisions and rank estimates will be used to analyze the updated bladder cancer incidence data. |
Lung cancer mortality in North Carolina and South Carolina chrysotile asbestos textile workers
Elliott L , Loomis D , Dement J , Hein MJ , Richardson D , Stayner L . Occup Environ Med 2012 69 (6) 385-90 OBJECTIVES: Studies of workers in two US cohorts of asbestos textile workers exposed to chrysotile (North Carolina (NC) and South Carolina (SC)) found increasing risk of lung cancer mortality with cumulative fibre exposure. However, the risk appeared to increase more steeply in SC, possibly due to differences in study methods. The authors conducted pooled analyses of the cohorts and investigated the exposure-disease relationship using uniform cohort inclusion criteria and statistical methods. METHODS: Workers were included after 30 days of employment in a production job during qualifying years, and vital status ascertained through 2003 (2001 for SC). Poisson regression was used to estimate the exposure-response relationship between asbestos and lung cancer, using both exponential and linear relative rate models adjusted for age, sex, race, birth cohort and decade of follow-up. RESULTS: The cohort included 6136 workers, contributing 218,631 person-years of observation and 3356 deaths. Cumulative exposures at the four study facilities varied considerably. The pooled relative rate for lung cancer, comparing 100 f-yr/ml to 0 f-yr/ml, was 1.11 (95% CI 1.06 to 1.16) for the combined cohort, with different effects in the NC cohort (RR=1.10, 95% CI 1.03 to 1.16) and the SC cohort (RR=1.67, 95% CI 1.44 to 1.93). CONCLUSIONS: Increased rates of lung cancer were significantly associated with cumulative fibre exposure overall and in both the Carolina asbestos-textile cohorts. Previously reported differences in exposure-response between the cohorts do not appear to be related to inclusion criteria or analytical methods. |
Body mass index, playing position, race, and the cardiovascular mortality of retired professional football players
Baron SL , Hein MJ , Lehman E , Gersic CM . Am J Cardiol 2012 109 (6) 889-96 Concern exists about cardiovascular disease (CVD) in professional football players. We examined whether playing position and size influence CVD mortality in 3,439 National Football League players with ≥5 pension-credited playing seasons from 1959 to 1988. Standardized mortality ratios (SMRs) compared player mortality through 2007 to the United States population of men stratified by age, race, and calendar year. Cox proportional hazards models evaluated associations of playing-time body mass index (BMI), race, and position with CVD mortality. Overall player mortality was significantly decreased (SMR 0.53, 95% confidence interval [CI] 0.48 to 0.59) as was mortality from cancer (SMR 0.58, 95% CI 0.46 to 0.72), and CVD (SMR 0.68, 95% CI 0.56 to 0.81). CVD mortality was increased for defensive linemen (SMR 1.42, 95% CI 1.02 to 1.92) but not for offensive linemen (SMR 0.70, 95% CI 0.45 to 1.05). Defensive linemen's cardiomyopathy mortality was also increased (SMR 5.34, 95% CI 2.30 to 10.5). Internal analyses found that CVD mortality was increased for players of nonwhite race (hazard ratio 1.69, 95% CI 1.13 to 2.51). After adjusting for age, race, and calendar year, CVD mortality was increased for those with a playing-time BMI ≥30 kg/m(2) (hazard ratio 2.02, 95% CI 1.06 to 3.85) and for defensive linemen compared to offensive linemen (hazard ratio 2.07, 95% CI 1.24 to 3.46). In conclusion, National Football League players from the 1959 through 1988 seasons had decreased overall mortality but those with a playing-time BMI ≥30 kg/m(2) had 2 times the risk of CVD mortality compared to other players and African-American players and defensive linemen had higher CVD mortality compared to other players even after adjusting for playing-time BMI. |
Inter-rater reliability of assessed prenatal maternal occupational exposures to solvents, polycyclic aromatic hydrocarbons, and heavy metals
Rocheleau CM , Lawson CC , Waters MA , Hein MJ , Stewart PA , Correa A , Echeverria D , Reefhuis J . J Occup Environ Hyg 2011 8 (12) 718-28 Because direct measurements of past occupational exposures are rarely available in population-based case-control studies, exposure assessment of job histories by multiple expert raters is frequently used; however, the subjective nature of this method makes measuring reliability an important quality control step. We evaluated inter-rater reliability of 7729 retrospective jobs reported in the National Birth Defects Prevention Study. Jobs were classified as exposed, unexposed, or exposure unknown by two independent industrial hygienists; exposed jobs were further evaluated for intensity, frequency, and routes. Exposure prevalence ranged from 0.1-9.8%. Inter-rater reliability for exposure (yes/no), assessed by kappa coefficients, was fair to good for cadmium (kappa = 0.46), chlorinated solvents (kappa = 0.59), cobalt (kappa = 0.54), glycol ethers (kappa = 0.50), nickel compounds (kappa = 0.65), oil mists (kappa = 0.63), and Stoddard Solvent (kappa = 0.55); PAHs (kappa = 0.24) and elemental nickel (kappa = 0.37) had poor agreement. After a consensus conference resolved disagreements, an additional 4962 jobs were evaluated. Inter-rater reliability improved or stayed the same for cadmium (kappa = 0.51), chlorinated solvents (kappa = 0.81), oil mists (kappa = 0.63), PAHs (kappa = 0.52), and Stoddard solvent (kappa = 0.92) in the second job set. Inter-rater reliability varied by exposure agent and prevalence, demonstrating the importance of measuring reliability in studies using a multiple expert rater method of exposure assessment. |
Assessment of occupational cosmic radiation exposure of flight attendants using questionnaire data
Anderson JL , Waters MA , Hein MJ , Schubauer-Berigan MK , Pinkerton LE . Aviat Space Environ Med 2011 82 (11) 1049-1054 INTRODUCTION: Female flight attendants may have a higher risk of breast and other cancers than the general population because of routine exposure to cosmic radiation. As part of a forthcoming study of breast and other cancer incidence, occupational cosmic radiation exposure of a cohort of female flight attendants was estimated. METHODS: Questionnaire data were collected from living female cohort members who were formerly employed as flight attendants with Pan American World Airways. These data included airline at which the flight attendant was employed, assigned domicile, start and end dates for employment at domicile, and number of block hours and commuter segments flown per month. Questionnaire respondents were assigned daily absorbed and effective doses using a time-weighted dose rate specific to the domicile and/or work history era combined with self-reported work history information. RESULTS: Completed work history questionnaires were received from 5898 living cohort members. Mean employment time as a flight attendant was 7.4 yr at Pan Am and 12 yr in total. Estimated mean annual effective dose from all sources of occupational cosmic radiation exposure was 2.5 +/- 1.0 mSv, with a mean career dose of 30 mSv. DISCUSSION: Annual effective doses were similar to doses assessed for other flight attendant cohorts; however, questionnaire-based cumulative doses assessed in this study were on average higher than those assessed for other flight attendant cohorts using company-based records. The difference is attributed to the inclusion of dose from work at other airlines and commuter flights, which was made possible by using questionnaire data. |
Cause-specific mortality among a cohort of U.S. flight attendants
Pinkerton LE , Waters MA , Hein MJ , Zivkovich Z , Schubauer-Berigan MK , Grajewski B . Am J Ind Med 2011 55 (1) 25-36 BACKGROUND: We evaluated mortality among 11,311 former U.S. flight attendants. The primary a priori outcomes of interest were breast cancer and melanoma. METHODS: Vital status was ascertained through 2007, and life table analyses was conducted. Cumulative exposure to cosmic radiation and circadian rhythm disruption were estimated from work history data and historical published flight schedules. RESULTS: All-cause mortality was less than expected among women but was elevated among men, primarily due to elevated HIV-related disease mortality. Mortality from breast cancer among women and melanoma was neither significantly elevated nor related to metrics of exposure. Mortality was elevated for non-Hodgkin's lymphoma among men; for alcoholism, drowning, and intentional self-harm among women; and for railway, water, and air transportation accidents. CONCLUSIONS: We found no evidence of increased breast cancer or melanoma mortality. Limitations include reliance on mortality data and limited power resulting from few melanoma deaths and relatively short employment durations. Am. J. Ind. Med. (c) 2011 Wiley Periodicals, Inc. |
Update of the NIOSH life table analysis system: a person-years analysis program for the windows computing environment
Schubauer-Berigan MK , Hein MJ , Raudabaugh WM , Ruder AM , Silver SR , Spaeth S , Steenland K , Petersen MR , Waters KM . Am J Ind Med 2011 54 (12) 915-24 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. |
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