Cancer incidence among boat-building workers exposed to styrene.

BACKGROUND: A cancer incidence analysis was conducted on The National Institute for Occupational Safety and Health boat-builders cohort exposed to styrene, a possible carcinogen. METHODS: Standardized incidence ratios (SIR) and standardized rate ratios (SRR) were calculated using national and Washington State rates and a person-years analysis program. RESULTS: Among 3704 workers living in Washington State after 1991, when cancer registry case accrual began, 516 first primary diagnoses occurred through 2007. While overall cancer incidence was significantly reduced [SIR: 0.83 (0.76, 0.90)], internal comparisons suggest an association with exposure comparing high to low exposed person-time [SRR: 1.28 (1.05, 1.55)]. CONCLUSION: There is evidence of styrene exposure being linked to cancer incidence, which is notable since the cohort has not yet reached the median age of cancer diagnosis (65) in the United States.

Cancer incidence among capacitor manufacturing workers exposed to polychlorinated biphenyls.

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. Am. J. Ind. Med. 60:198-207, 2017. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Non-malignant respiratory disease among workers in industries using styrene-A review of the evidence.

BACKGROUND: Asthma and obliterative bronchiolitis (OB) cases have occurred among styrene-exposed workers. We aimed to investigate styrene as a risk factor for non-malignant respiratory disease (NMRD). METHODS: From a literature review, we identified case reports and assessed cross-sectional and mortality studies for strength of evidence of positive association (i.e., strong, intermediate, suggestive, none) between styrene exposure and NMRD-related morbidity and mortality. RESULTS: We analyzed 55 articles and two unpublished case reports. Ten OB cases and eight asthma cases were identified. Six (75%) asthma cases had abnormal styrene inhalation challenges. Thirteen (87%) of 15 cross-sectional studies and 12 (50%) of 24 mortality studies provided at least suggestive evidence that styrene was associated with NMRD-related morbidity or mortality. Six (66%) of nine mortality studies assessing chronic obstructive pulmonary disease-related mortality indicated excess mortality. CONCLUSIONS: Available evidence suggests styrene exposure is a potential risk factor for NMRD. Additional studies of styrene-exposed workers are warranted. Am. J. Ind. Med. 60:163-180, 2017. © 2016 Wiley Periodicals, Inc.

Mortality among styrene-exposed workers in the reinforced plastic boatbuilding industry.

BACKGROUND: We updated mortality through 2011 for 5203 boat-building workers potentially exposed to styrene, and analysed mortality among 1678 employed a year or more between 1959 and 1978. The a priori hypotheses: excess leukaemia and lymphoma would be found. METHODS: Standardised mortality ratios (SMRs) and 95% CIs and standardised rate ratios (SRRs) used Washington State rates and a person-years analysis programme, LTAS.NET. The SRR analysis compared outcomes among tertiles of estimated cumulative potential styrene exposure. RESULTS: Overall, 598 deaths (SMR=0.96, CI 0.89 to 1.04) included excess lung (SMR=1.23, CI 0.95 to 1.56) and ovarian cancer (SMR 3.08, CI 1.00 to 7.19), and chronic obstructive pulmonary disease (COPD) (SMR=1.15, CI 0.81 to 1.58). Among 580 workers with potential high-styrene exposure, COPD mortality increased 2-fold (SMR=2.02, CI 1.08 to 3.46). CONCLUSIONS: COPD was more pronounced among those with potential high-styrene exposure. However, no outcome was related to estimated cumulative styrene exposure, and there was no change when latency was taken into account. We found no excess leukaemia or lymphoma mortality. As in most occupational cohort studies, lack of information on lifestyle factors or other employment was a substantial limitation although we excluded from the analyses those (n=3525) who worked <1 year. Unanticipated excess ovarian cancer mortality could be a chance finding. Comparing subcohorts with potential high-styrene and low-styrene exposure, COPD mortality SRR was elevated while lung cancer SRR was not, suggesting that smoking was not the only cause for excess COPD mortality.

Further Confirmation of Germline Glioma Risk Variant rs78378222 in TP53 and Its Implication in Tumor Tissues via Integrative Analysis of TCGA Data.

We confirmed strong association of rs78378222:A>C (per allele odds ratio [OR] = 3.14; P = 6.48 × 10(-11) ), a germline rare single-nucleotide polymorphism (SNP) in TP53, via imputation of a genome-wide association study of glioma (1,856 cases and 4,955 controls). We subsequently performed integrative analyses on the Cancer Genome Atlas (TCGA) data for GBM (glioblastoma multiforme) and LUAD (lung adenocarcinoma). Based on SNP data, we imputed genotypes for rs78378222 and selected individuals carrying rare risk allele (C). Using RNA sequencing data, we observed aberrant transcripts with ∼3 kb longer than normal for those individuals. Using exome sequencing data, we further showed that loss of haplotype carrying common protective allele (A) occurred somatically in GBM but not in LUAD. Our bioinformatic analysis suggests rare risk allele (C) disrupts mRNA termination, and an allelic loss of a genomic region harboring common protective allele (A) occurs during tumor initiation or progression for glioma.

Immunoglobulin genes influence the magnitude of humoral immunity to cytomegalovirus glycoprotein B.

Human cytomegalovirus (HCMV) is a risk factor for many human diseases, but among exposed individuals, not everyone is equally likely to develop HCMV-spurred diseases, implying the presence of host genetic factors that might modulate immunity to this virus. Here, we show that antibody responsiveness to HCMV glycoprotein B (gB) is significantly associated with particular immunoglobulin GM (γ marker) genotypes. Anti-HCMV gB antibody levels were highest in GM 17/17 homozygotes, intermediate in GM 3/17 heterozygotes, and lowest in GM 3/3 homozygotes (28.2, 19.0, and 8.1 µg/mL, respectively; P=.014). These findings provide mechanistic insights in the etiopathogenesis of HCMV-spurred diseases.

Bladder cancer incidence among workers exposed to o-toluidine, aniline and nitrobenzene at a rubber chemical manufacturing plant.

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.

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.

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.

Known glioma risk loci are associated with glioma with a family history of brain tumours -- a case-control gene association study.

Familial cancer can be used to leverage genetic association studies. Recent genome-wide association studies have reported independent associations between seven single nucleotide polymorphisms (SNPs) and risk of glioma. The aim of this study was to investigate whether glioma cases with a positive family history of brain tumours, defined as having at least one first- or second-degree relative with a history of brain tumour, are associated with known glioma risk loci. One thousand four hundred and thirty-one glioma cases and 2,868 cancer-free controls were identified from four case-control studies and two prospective cohorts from USA, Sweden and Denmark and genotyped for seven SNPs previously reported to be associated with glioma risk in case-control designed studies. Odds ratios were calculated by unconditional logistic regression. In analyses including glioma cases with a family history of brain tumours (n = 104) and control subjects free of glioma at baseline, three of seven SNPs were associated with glioma risk: rs2736100 (5p15.33, TERT), rs4977756 (9p21.3, CDKN2A-CDKN2B) and rs6010620 (20q13.33, RTEL1). After Bonferroni correction for multiple comparisons, only one marker was statistically significantly associated with glioma risk, rs6010620 (ORtrend for the minor (A) allele, 0.39; 95% CI: 0.25-0.61; Bonferroni adjusted ptrend , 1.7 × 10(-4) ). In conclusion, as previously shown for glioma regardless of family history of brain tumours, rs6010620 (RTEL1) was associated with an increased risk of glioma when restricting to cases with family history of brain tumours. These findings require confirmation in further studies with a larger number of glioma cases with a family history of brain tumours.

Joint effects between five identified risk variants, allergy, and autoimmune conditions on glioma risk.

Common variants in two of the five genetic regions recently identified from genome-wide association studies (GWAS) of risk of glioma were reported to interact with a history of allergic symptoms. In a pooled analysis of five epidemiologic studies, we evaluated the association between the five GWAS implicated gene variants and allergies and autoimmune conditions (AIC) on glioma risk (851 adult glioma cases and 3,977 controls). We further evaluated the joint effects between allergies and AIC and these gene variants on glioma risk. Risk estimates were calculated as odds ratios (OR) and 95 % confidence intervals (95 % CI), adjusted for age, gender, and study. Joint effects were evaluated by conducting stratified analyses whereby the risk associations (OR and 95 % CI) with the allergy or autoimmune conditions for glioma were evaluated by the presence or absence of the 'at-risk' variant, and estimated p interaction by fitting models with the main effects of allergy or autoimmune conditions and genotype and an interaction (product) term between them. Four of the five SNPs previously reported by others were statistically significantly associated with increased risk of glioma in our study (rs2736100, rs4295627, rs4977756, and rs6010620); rs498872 was not associated with glioma in our study. Reporting any allergies or AIC was associated with reduced risks of glioma (allergy: adjusted OR = 0.71, 95 % CI 0.55-0.91; AIC: adjusted OR = 0.65, 95 % CI 0.47-0.90). We did not observe differential association between allergic or autoimmune conditions and glioma by genotype, and there were no statistically significant p interactions. Stratified analysis by glioma grade (low and high grade) did not suggest risk differences by disease grade. Our results do not provide evidence that allergies or AIC modulate the association between the four GWAS-identified SNPs examined and risk of glioma.

The Upper Midwest Health Study: gliomas and occupational exposure to chlorinated solvents.

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.

Genome-wide association study of glioma and meta-analysis.

Gliomas account for approximately 80 % of all primary malignant brain tumors and, despite improvements in clinical care over the last 20 years, remain among the most lethal tumors, underscoring the need for gaining new insights that could translate into clinical advances. Recent genome-wide association studies (GWAS) have identified seven new susceptibility regions. We conducted a new independent GWAS of glioma using 1,856 cases and 4,955 controls (from 14 cohort studies, 3 case-control studies, and 1 population-based case-only study) and found evidence of strong replication for three of the seven previously reported associations at 20q13.33 (RTEL), 5p15.33 (TERT), and 9p21.3 (CDKN2BAS), and consistent association signals for the remaining four at 7p11.2 (EGFR both loci), 8q24.21 (CCDC26) and 11q23.3 (PHLDB1). The direction and magnitude of the signal were consistent for samples from cohort and case-control studies, but the strength of the association was more pronounced for loci rs6010620 (20q,13.33; RTEL) and rs2736100 (5p15.33, TERT) in cohort studies despite the smaller number of cases in this group, likely due to relatively more higher grade tumors being captured in the cohort studies. We further examined the 85 most promising single nucleotide polymorphism (SNP) markers identified in our study in three replication sets (5,015 cases and 11,601 controls), but no new markers reached genome-wide significance. Our findings suggest that larger studies focusing on novel approaches as well as specific tumor subtypes or subgroups will be required to identify additional common susceptibility loci for glioma risk.

The Upper Midwest Health Study: a case-control study of pesticide applicators and risk of glioma.

BACKGROUND: An excess incidence of brain cancer in farmers has been noted in several studies. The National Institute for Occupational Safety and Health developed the Upper Midwest Health Study (UMHS) as a case-control study of intracranial gliomas and pesticide uses among rural residents. Previous studies of UMHS participants, using "ever-never" exposure to farm pesticides and analyzing men and women separately, found no positive association of farm pesticide exposure and glioma risks. The primary objective was to determine if quantitatively estimated exposure of pesticide applicators was associated with an increased risk of glioma in male and female participants. METHODS: The study included 798 histologically confirmed primary intracranial glioma cases (45 % with proxy respondents) and 1,175 population-based controls, all adult (age 18-80) non-metropolitan residents of Iowa, Michigan, Minnesota, and Wisconsin. The analyses used quantitatively estimated exposure from questionnaire responses evaluated by an experienced industrial hygienist with 25 years of work on farm pesticide analyses. Odds ratios (ORs) and 95 % confidence intervals (CIs) using unconditional logistic regression modeling were calculated adjusting for frequency-matching variables (10-year age group and sex), and for age and education (a surrogate for socioeconomic status). Analyses were separately conducted with or without proxy respondents. RESULTS: No significant positive associations with glioma were observed with cumulative years or estimated lifetime cumulative exposure of farm pesticide use. There was, a significant inverse association for phenoxy pesticide used on the farm (OR 0.96 per 10 g-years of cumulative exposure, CI 0.93-0.99). No significant findings were observed when proxy respondents were excluded. Non-farm occupational applicators of any pesticide had decreased glioma risk: OR 0.72, CI 0.52-0.99. Similarly, house and garden pesticide applicators had a decreased risk of glioma: OR 0.79, CI 0.66-0.93, with statistically significant inverse associations for use of 2,4-D, arsenates, organophosphates, and phenoxys. CONCLUSIONS: These results are consistent with our previous findings for UMHS of reported farm pesticide exposure and support a lack of positive association between pesticides and glioma.

The Upper Midwest Health Study: industry and occupation of glioma cases and controls.

BACKGROUND: Understanding glioma etiology requires determining which environmental factors are associated with glioma. Upper Midwest Health Study case-control participant work histories collected 1995-1998 were evaluated for occupational associations with glioma. "Exposures of interest" from our study protocol comprise our a priori hypotheses. MATERIALS AND METHODS: Year-long or longer jobs for 1,973 participants were assigned Standard Occupational Classifications (SOC) and Standard Industrial Classifications (SIC). The analysis file includes 8,078 SIC- and SOC-coded jobs. For each individual, SAS 9.2 programs collated employment with identical SIC-SOC coding. Distributions of longest "total employment duration" (total years worked in jobs with identical industry and occupation codes, including multiple jobs, and non-consecutive jobs) were compared between cases and controls, using an industrial hygiene algorithm to group occupations. RESULTS: Longest employment duration was calculated for 780 cases and 1,156 controls. More case than control longest total employment duration was in the "engineer, architect" occupational group [16 cases, 10 controls, odds ratio (OR) 2.50, adjusted for age group, sex, age and education, 95% confidence interval (CI) 1.12-5.60]. Employment as a food processing worker [mostly butchers and meat cutters] was of borderline significance (27 cases, 21 controls, adjusted OR: 1.78, CI: 0.99-3.18). CONCLUSIONS: Among our exposures of interest work as engineers or as butchers and meat cutters was associated with increased glioma risk. Significant associations could be due to chance, because of multiple comparisons, but similar findings have been reported for other glioma studies. Our results suggest some possible associations but by themselves could not provide conclusive evidence.

Exposure to o-toluidine, aniline, and nitrobenzene in a rubber chemical manufacturing plant: a retrospective exposure assessment update.

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.

Joint associations between genetic variants and reproductive factors in glioma risk among women.

In a pooled analysis of 4 US epidemiologic studies (1993-2001), the authors evaluated the role of 5 female reproductive factors in 357 women with glioma and 822 controls. The authors further evaluated the independent association between 5 implicated gene variants and glioma risk among the study population, as well as the joint associations of female reproductive factors (ages at menarche and menopause, menopausal status, use of oral contraceptives, and menopausal hormone therapy) and these gene variants on glioma risk. Risk estimates were calculated as odds ratios and 95% confidence intervals that were adjusted for age, race, and study. Three of the gene variants (rs4295627, a variant of CCDC26; rs4977756, a variant of CDKN2A and CDKN2B; and rs6010620, a variant of RTEL1) were statistically significantly associated with glioma risk in the present population. Compared with women who had an early age at menarche (<12 years of age), those who reported menarche at 12-13 years of age or at 14 years of age or older had a 1.7-fold higher risk and a 1.9-fold higher risk of glioma, respectively (P for trend = 0.009). Postmenopausal women and women who reported ever having used oral contraceptives had a decreased risk of glioma. The authors did not observe joint associations between these reproductive characteristics and the implicated glioma gene variants. These results require replication, but if confirmed, they would suggest that the gene variants that have previously been implicated in the development of glioma are unlikely to act through the same hormonal mechanisms in women.

Mortality and end-stage renal disease incidence among dry cleaning workers.

OBJECTIVE: Perchloroethylene (PCE) is a known animal carcinogen and probable human carcinogen. Dry cleaning exposures, particularly PCE, are also associated with renal toxicity. The objective was to follow-up a cohort of dry cleaners to evaluate mortality and assess end-stage renal disease (ESRD) morbidity. METHODS: This study adds 8 years of mortality follow-up for 1704 dry cleaning workers in four cities. Employees eligible for inclusion worked for ≥1 year before 1960 in a shop using PCE as the primary solvent. Life table analyses for mortality and ESRD morbidity were conducted. Only employees alive on 1 January 1977 were included in ESRD analyses. RESULTS: Overall cancer deaths were in significant excess in this cohort (standardised mortality ratio (SMR) 1.22, 95% CI 1.09 to 1.36). Oesophageal, lung and tongue cancers had significant excesses of deaths. Oesophageal cancer risk was highest among those employed in a PCE-using shop for ≥5 years with ≥20 years' latency since first such employment. Deaths from non-malignant underlying diseases of the stomach and duodenum were in significant excess. Hypertensive ESRD morbidity was significantly elevated in the entire cohort (standardised incidence ratio (SIR) 1.98, 95% CI 1.11 to 3.27), and among workers employed only in PCE-using dry cleaning shops for ≥5 years. CONCLUSION: Employment in the dry cleaning industry and occupational exposure to PCE are associated with an increased risk for ESRD and for cancer at several sites. The employment duration findings for oesophageal cancer and hypertensive ESRD further support an association with PCE exposure instead of lifestyle or socioeconomic factors.

Cytogenetic analysis of an exposed-referent study: perchloroethylene-exposed dry cleaners compared to unexposed laundry workers.

BACKGROUND: Significant numbers of people are exposed to tetrachloroethylene (perchloroethylene, PCE) every year, including workers in the dry cleaning industry. Adverse health effects have been associated with PCE exposure. However, investigations of possible cumulative cytogenetic damage resulting from PCE exposure are lacking. METHODS: Eighteen dry cleaning workers and 18 laundry workers (unexposed controls) provided a peripheral blood sample for cytogenetic analysis by whole chromosome painting. Pre-shift exhaled air on these same participants was collected and analyzed for PCE levels. The laundry workers were matched to the dry cleaners on race, age, and smoking status. The relationships between levels of cytological damage and exposures (including PCE levels in the shop and in workers' blood, packyears, cumulative alcohol consumption, and age) were compared with correlation coefficients and t-tests. Multiple linear regressions considered blood PCE, packyears, alcohol, and age. RESULTS: There were no significant differences between the PCE-exposed dry cleaners and the laundry workers for chromosome translocation frequencies, but PCE levels were significantly correlated with percentage of cells with acentric fragments (R2 = 0.488, p < 0.026). CONCLUSIONS: There does not appear to be a strong effect in these dry cleaning workers of PCE exposure on persistent chromosome damage as measured by translocations. However, the correlation between frequencies of acentric fragments and PCE exposure level suggests that recent exposures to PCE may induce transient genetic damage. More heavily exposed participants and a larger sample size will be needed to determine whether PCE exposure induces significant levels of persistent chromosome damage.

Maternal exposure to polychlorinated biphenyls and the secondary sex ratio: an occupational cohort study.

BACKGROUND: Though commercial production of polychlorinated biphenyls was banned in the United States in 1977, exposure continues due to their environmental persistence. Several studies have examined the association between environmental polychlorinated biphenyl exposure and modulations of the secondary sex ratio, with conflicting results. OBJECTIVE: Our objective was to evaluate the association between maternal preconceptional occupational polychlorinated biphenyl exposure and the secondary sex ratio. METHODS: We examined primipara singleton births of 2595 women, who worked in three capacitor plants at least one year during the period polychlorinated biphenyls were used. Cumulative estimated maternal occupational polychlorinated biphenyl exposure at the time of the infant's conception was calculated from plant-specific job-exposure matrices. A logistic regression analysis was used to evaluate the association between maternal polychlorinated biphenyl exposure and male sex at birth (yes/no). RESULTS: Maternal body mass index at age 20, smoking status, and race did not vary between those occupationally exposed and those unexposed before the child's conception. Polychlorinated biphenyl-exposed mothers were, however, more likely to have used oral contraceptives and to have been older at the birth of their first child than non-occupationally exposed women. Among 1506 infants liveborn to polychlorinated biphenyl-exposed primiparous women, 49.8% were male; compared to 49.9% among those not exposed (n = 1089). Multivariate analyses controlling for mother's age and year of birth found no significant association between the odds of a male birth and mother's cumulative estimated polychlorinated biphenyl exposure to time of conception. CONCLUSIONS: Based on these data, we find no evidence of altered sex ratio among children born to primiparous polychlorinated biphenyl-exposed female workers.

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.