Long-term occupational exposures on disability-free survival and mortality in older adults.

BACKGROUND: The impact of long-term occupational exposures on health in older adults is increasingly relevant as populations age. To date, no studies have reported their impact on survival free of disability in older adults. AIMS: We aimed to investigate the association between long-term occupational exposure and disability-free survival (DFS), all-cause mortality and cause-specific mortality in initially healthy older adults. METHODS: We analysed data from 12 215 healthy participants in the ASPirin in Reducing Events in the Elderly (ASPREE) study whose mean age was 75 years. Their work history was collated with the 'ALOHA-plus JEM' (Job Exposure Matrix) to assign occupational exposures. The primary endpoint, DFS, was a composite measure of death, dementia or persistent physical disability. The secondary endpoint, mortality, was classified according to the underlying cause. Cox proportional hazard models were used to calculate hazard ratios and 95% confidence intervals, adjusted for confounders. RESULTS: A total of 1835 individuals reached the DFS endpoint during the median 4.7 years follow-up period. Both ever-high and cumulative exposure to all dusts and all pesticides during a person's working years were associated with reduced DFS. Compared to no exposure, men with high exposure to dusts and pesticides had a reduced DFS. Neither of these exposures were significantly associated with all-cause mortality. Men with high occupational exposure to solvents and women exposed to dusts experienced higher all-cause and cancer-related mortality. CONCLUSIONS: Long-term occupational exposure to all dusts and pesticides was associated with a reduced DFS and increased mortality in community-dwelling healthy older adults.

Maternal occupational exposure to endocrine-disrupting chemicals and urogenital anomalies in the offspring.

STUDY QUESTION: Is there an association between maternal occupational exposure to endocrine-disrupting chemicals (EDCs) early in pregnancy and subgroups of congenital anomalies of kidney and urinary tract (CAKUT), and hypospadias? SUMMARY ANSWER: Exposure to specific EDCs can increase the risk of CAKUT and no association with hypospadias was observed. WHAT IS KNOWN ALREADY: Previous studies showed an association between maternal occupational exposure to EDCs and hypospadias. However, little is known about the effect of these chemicals on the development of CAKUT, especially subgroups of urinary tract anomalies. STUDY DESIGN, SIZE, DURATION: For this case-control study, cases with urogenital anomalies from the European Concerted Action on Congenital Anomalies and Twins Northern Netherlands (Eurocat NNL) registry and non-malformed controls from the Lifelines children cohort (living in the same catchment region as Eurocat NNL) born between 1997 and 2013 were selected. This study included 530 cases with CAKUT, 364 cases with hypospadias, 7 cases with both a urinary tract anomaly and hypospadias and 5602 non-malformed controls. Cases with a genetic or chromosomal anomaly were excluded, and to avoid genetic correlation, we also excluded cases in which a sibling with the same defect was included. PARTICIPANTS/MATERIALS, SETTING, METHODS: Information on maternal occupation held early in pregnancy was collected via self-administered questionnaires. Job titles were translated into occupational exposure to EDCs using a job-exposure matrix (JEM). Adjusted odds ratios (aORs) and 95% CIs were estimated to assess the association between maternal occupational exposure to EDCs (and to specific types of EDCs) and CAKUT and hypospadias. MAIN RESULTS AND THE ROLE OF CHANCE: For CAKUT and hypospadias, 23.1% and 22.9% of the cases were exposed to EDCs, respectively, whereas 19.8% of the controls were exposed. We found an association between maternal occupational exposure to organic solvents/alkylphenolic compounds and CAKUT (aOR 1.41, 95% CI 1.01-1.97) that became stronger when combinations of urinary tract anomalies co-occurred with other defects (aOR 7.51, 95% CI 2.41-23.43). An association was also observed for exposure to phthalates/benzophenones/parabens/siloxanes and CAKUT (aOR 1.56, 95% CI 1.06-2.29), specifically urinary collecting system anomalies (aOR 1.62, 95% CI 1.03-2.54) and combinations of urinary tract anomalies (aOR 2.90, 95% CI 1.09-7.71). We observed no association between EDC exposure and hypospadias. LIMITATIONS, REASONS FOR CAUTION: The different study designs of Eurocat NNL and Lifelines could have introduced differential information bias. Also, exposure misclassification could be an issue: it is possible that the actual exposure differed from the exposure estimated by the JEM. In addition, women could also have been exposed to other exposures not included in the analysis, which could have resulted in residual confounding by co-exposures. WIDER IMPLICATIONS OF THE FINDINGS: Women, their healthcare providers, and their employers need to be aware that occupational exposure to specific EDCs early in pregnancy may be associated with CAKUT in their offspring. An occupational hygienist should be consulted in order to take exposure to those specific EDCs into consideration when risk assessments are carried out at the workplace. STUDY FUNDING/COMPETING INTEREST(S): N.S. was paid by the Graduate School of Medical Sciences (MD/PhD programme), University Medical Center Groningen (UMCG), Groningen, the Netherlands. Eurocat Northern Netherlands is funded by the Dutch Ministry of Health, Welfare and Sports. The Lifelines Biobank initiative has been made possible by subsidy from the Dutch Ministry of Health, Welfare and Sport, the Dutch Ministry of Economic Affairs, the University Medical Center Groningen (UMCG the Netherlands), University Groningen and the Northern Provinces of the Netherlands. The authors report no conflict of interest. TRIAL REGISTRATION NO: N/A.

Possible causes of aberrations in adverse grouping behavior of dairy cows: A field study.

In the Dutch national surveillance system, an increasing number of reports were received in the summer of 2017 from farmers about unusual behavior of their cows. The cows were grouping during the day in summer in one part of the barn and did not move for several hours, which, according to the farmers, led to reduced food and water intake and lying time and resulted in decreased milk production and increased risk of lameness. Many farmers perceived magnetic fields from, for instance, high-voltage lines, automated milking systems, or solar panels as possible causes for the behavior of their cows. Our aim for the study was to study potential factors such as magnetic fields and other factors such as barn climate and insect burden for adverse grouping behavior of dairy cows in the barn. For each case herd, 2 control herds were selected in the same postal area code. A case was a herd in which cattle grouped at least on 7 occasions in a month for several hours. In a control herd, the cows were in the barn during the same time period as in the matching case herd but did not show adverse grouping behavior. A questionnaire was administered by telephone in 31 case herds and 62 control herds. The questionnaire gathered information on behavior of the cows and potential risk factors. In addition, data on the distance of the herd to high-voltage lines was obtained. From a total of 74 variables, all variables with a P-value ≤0.10 were included in full multivariable logistic regression model. Backward selection was carried out at P ≤ 0.10. The grouping behavior of the cows started in most herds in June, was seen only during the day, and lasted mostly 6 to 8 h, with cows often grouped in the northern part of the barn. Identified risk factors appeared to be recently constructed barns, measured stray voltage in barns, and presence of fans in barns. Given the cross-sectional design of the case-control study, causality for these risk factors leading to adverse behavior of the cows could not be proven. Dissemination of the results to farmers hopefully results in measures that can prevent the unusual grouping behavior of cows.

Immunoreactivity to metal and silica associates with sarcoidosis in Dutch patients.

BACKGROUND: Involvement of metals or silica in the pathogenesis of sarcoidosis has been suggested by several case reports and specific epidemiological studies. However, the combination of occupational exposure and an immunological reaction has not been studied before in a group of sarcoidosis patients and non-sarcoidosis controls. METHODS: In 256 sarcoidosis patients and 73 control patients with obstructive sleep apnea, exposure to metal and silica was assessed using a questionnaire consisting of a complete occupational history subsequently linked to job-exposure matrices. Next, immunoreactivity to aluminium, beryllium, zirconium and silica was determined in 33 sarcoidosis and 19 control patients using a lymphocyte proliferation test. RESULTS: In sarcoidosis, 83 out 256 patients (32.4%) had occupational exposure to metals or silica, compared to 24.7% in the control group (p = 0.21). A significantly higher percentage of the sarcoidosis patients tested showed immunoreactivity to metals or silica compared to the control group (21.2 and 0% respectively, p = 0.039). CONCLUSIONS: Immunoreactivity to silica and metals was only found in sarcoidosis patients, supporting the hypothesis that these antigens may be involved in the pathogenesis of a distinct subgroup of sarcoidosis patients. This indicates that when searching for causative agents in sarcoidosis patients, besides beryllium, also zirconium, aluminium and silica deserve clinical investigation.

Congenital anomalies in the offspring of occupationally exposed mothers: a systematic review and meta-analysis of studies using expert assessment for occupational exposures.

STUDY QUESTION: Is there an association between maternal occupational exposure to solvents, pesticides and metals as assessed by expert-based assessment and congenital anomalies in the offspring? SUMMARY ANSWER: There is an association between maternal occupational exposure to solvents and congenital anomalies in the offspring, including neural tube defects, congenital heart defects and orofacial clefts. WHAT IS KNOWN ALREADY: One important environmental risk factor for development of congenital anomalies is maternal occupational exposure to chemicals in the workplace prior to and during pregnancy. A number of studies have assessed the association with often conflicting results, possibly due to different occupational exposure assessing methods. STUDY DESIGN, SIZE, DURATION: For this systematic review with meta-analysis, the search terms included maternal occupation, exposure, congenital anomalies and offspring. Electronic databases MEDLINE and EMBASE were searched for English studies up to October 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Two reviewers independently screened all citations identified by the search. Case-control studies and cohort studies were included if (I) they reported on the association between maternal occupational exposure to solvents, pesticides or metals and congenital anomalies, and (II) assessment of occupational exposure was performed by experts. Data on study characteristics, confounders and odds ratios (ORs) were extracted from the included studies for four subgroups of congenital anomalies. Methodological quality was assessed using the Newcastle-Ottawa Scale. In the meta-analysis, random effects models were used to pool estimates. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 2806 titles and abstracts and 176 full text papers were screened. Finally, 28 studies met the selection criteria, and 27 studies could be included in the meta-analysis. Our meta-analysis showed that maternal occupational exposure to solvents was associated with neural tube defects (OR: 1.51, 95%CI: 1.09-2.09) and congenital heart defects (OR: 1.31, 95%CI:1.06-1.63) in the offspring. Also maternal occupational exposure to glycol ethers, a subgroup of solvents, was associated with neural tube defects (OR: 1.93, 95%CI: 1.17-3.18) and orofacial clefts (OR: 1.95, 95%CI: 1.38-2.75) in the offspring. Only one study investigated the association between maternal occupational exposure to solvents and hypospadias and found an association (OR: 3.63, 95%CI: 1.94-7.17). Results of the included studies were consistent. In our meta-analysis, we found no associations between occupational exposure to pesticides or metals and congenital anomalies in the offspring. LIMITATIONS, REASONS FOR CAUTION: A limited number of studies was included, which made it impossible to calculate pooled estimates for all congenital anomalies, analyse individual chemicals or calculate exposure-response relations. Bias could have been introduced because not all included studies corrected for potentially confounding factors. WIDER IMPLICATIONS OF THE FINDINGS: Employers and female employees should be aware of the possible teratogenic effects of solvent exposure at the workplace. Therefore, is it important that clinicians and occupational health specialist provide women with preconception advice on occupational solvent exposure, to reduce the congenital anomaly risk. STUDY FUNDING/COMPETING INTEREST(S): NSp was paid by the Graduate School of Medical Sciences (MD/PhD program), UMCG, Groningen, the Netherlands. EUROCAT Northern Netherlands is funded by the Dutch Ministry of Health, Welfare and Sports. There are no competing interests. REGISTRATION NUMBER: CRD42017053943.

A survey on abnormal uterine bleeding among radiographers with frequent MRI exposure using intrauterine contraceptive devices.

PURPOSE: Based on a previous case report of menometrorrhagia (prolonged/excessive uterine bleeding, occurring at irregular and/or frequent intervals) in MRI workers with intrauterine devices (IUDs), it was evaluated whether this association could be confirmed. METHODS: A survey was performed among 381 female radiographers registered with their national association. Logistic regression was used to analyze associations of abnormal uterine bleeding with the frequency of working with MRI scanners, presence near the scanner/in the scanner room during image acquisition, and with scanner strength or type. RESULTS: A total of 68 women reported using IUDs, and 72 reported abnormal uterine bleeding. Compared with unexposed women not using IUDs, the odds ratio in women with IUDs working with MRI scanners was 2.09 (95% confidence interval 0.83-3.66). Associations were stronger if women working with MRI reported being present during image acquisition (odds ratio 3.43, 95% CI 1.26-9.34). Associations with scanner strength or type were not consistent. CONCLUSIONS: Radiographers using IUDs who are occupationally exposed to stray fields from MRI scanners report abnormal uterine bleeding more often than their co-workers without an IUD, or nonexposed co-workers with an IUD. In particular, radiographers present inside the scanner room during image acquisition showed an increased risk. Magn Reson Med 79:1083-1089, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Pesticides and other occupational exposures are associated with airway obstruction: the LifeLines cohort study.

OBJECTIVES: Occupational exposures are important and possibly modifiable contributors to the global burden of chronic obstructive pulmonary disease (COPD). Exposure to vapours, gases, dusts and fumes (VGDF) has been associated with a two- to threefold higher COPD risk. Less is known about effects of occupational exposure to pesticides and solvents. In the current study, we assessed if VGDF, pesticides and solvents are associated with the level of lung function and the prevalence of airway obstruction in the general population. METHODS: We included 11 851 subjects aged 18-89 years from the LifeLines cohort study. Regression models assessing associations between occupational exposures (no/low/high), level of lung function (prebronchodilator FEV(1), FEV(1)/FVC) and mild and moderate/severe airway obstruction were adjusted for sex, age, height, weight, current/ex-smoking and packyears. Additionally, we stratified by smoking status and gender and tested for interaction. A second general population cohort (n=2364) was used to verify our initial findings. RESULTS: Occupational exposure to VGDF and pesticides was associated with a lower level of FEV(1) and FEV(1)/FVC and with a higher prevalence of mild and moderate/severe airway obstruction in the two general populations investigated. There were no associations with exposure to solvents. CONCLUSIONS: Occupational exposure to both VGDF and pesticides is associated with airway obstruction in the general population.

Interactions between SERPINA1 PiMZ genotype, occupational exposure and lung function decline.

OBJECTIVES: We evaluated interactions between SERPINA1 PiMZ genotype, associated with intermediate α1-antitrysin deficiency, with outdoor particulate matter ≤10 µm (PM10), and occupational exposure to vapours, dusts, gases and fumes (VGDF), and their effects on annual change in lung function. METHODS: Pre-bronchodilator spirometry was performed in 3739 adults of the Swiss Cohort Study on Air Pollution and Lung Disease in Adults (SAPALDIA) for whom SERPINA1 genotypes were available. At baseline in 1991, participants were aged 18-62 years; follow-up measurements were conducted from 2001 to 2003. In linear mixed regression models of annual change in lung function, multiplicative interactions were evaluated between PiMZ genotype (PiMM as reference) and change in PM10 (µg/m(3)), and VGDF exposure (high-level, low-level or no exposure as reference) during follow-up. RESULTS: Annual declines in forced expiratory flow at 25-75% of forced vital capacity (FEF25-75%) (-82 mL/s, 95% CI -125 to -39) and forced expiratory volume in 1 s over forced vital capacity (FEV1/FVC) (-0.3%, 95% CI -0.6% to 0.0%) in association with VGDF exposure were observed only in PiMZ carriers (Pinteraction<0.0001 and Pinteraction=0.03, respectively). A three-way interaction between PiMZ genotype, smoking and VGDF exposure was identified such that VGDF-associated FEF25-75% decline was observed only in ever smoking PiMZ carriers (Pinteraction=0.01). No interactions were identified between PiMZ genotype and outdoor PM10. CONCLUSIONS: SERPINA1 PiMZ genotype, in combination with smoking, modified the association between occupational VGDF exposure and longitudinal change in lung function, suggesting that interactions between these factors are relevant for lung function decline. These novel findings warrant replication in larger studies.

Perinatal asphyxia in monochorionic versus dichorionic twins: incidence, risk factors and outcome.

OBJECTIVE: To estimate the incidence, risk factors, severity and outcome after perinatal asphyxia in monochorionic (MC) versus dichorionic (DC) twins. METHODS: We included all consecutive near-term MC and DC twins with perinatal asphyxia admitted to our neonatal ward between 2004 and 2013 and compared the perinatal characteristics and neonatal outcome between both groups. RESULTS: The incidence of perinatal asphyxia in MC and DC twin infants was 4.0 (11/272) and 4.0% (8/200; p = 1.00). In contrast to DC twins, asphyxia in MC twins was strongly associated with acute exsanguination and anemia at birth; 64% (7/11) in MC twins and 0% (0/8) in DC twins (p < 0.01). Median hemoglobin level at birth in the MC and DC groups was 11.5 and 18.6 g/dl, respectively (p < 0.01). CONCLUSIONS: Perinatal asphyxia in MC twins is often associated with severe anemia at birth due to acute hemorrhage through the placental vascular anastomoses.

Wireless phone use in childhood and adolescence and neuroepithelial brain tumours: Results from the international MOBI-Kids study.

In recent decades, the possibility that use of mobile communicating devices, particularly wireless (mobile and cordless) phones, may increase brain tumour risk, has been a concern, particularly given the considerable increase in their use by young people. MOBI-Kids, a 14-country (Australia, Austria, Canada, France, Germany, Greece, India, Israel, Italy, Japan, Korea, the Netherlands, New Zealand, Spain) case-control study, was conducted to evaluate whether wireless phone use (and particularly resulting exposure to radiofrequency (RF) and extremely low frequency (ELF) electromagnetic fields (EMF)) increases risk of brain tumours in young people. Between 2010 and 2015, the study recruited 899 people with brain tumours aged 10 to 24 years old and 1,910 controls (operated for appendicitis) matched to the cases on date of diagnosis, study region and age. Participation rates were 72% for cases and 54% for controls. The mean ages of cases and controls were 16.5 and 16.6 years, respectively; 57% were males. The vast majority of study participants were wireless phones users, even in the youngest age group, and the study included substantial numbers of long-term (over 10 years) users: 22% overall, 51% in the 20-24-year-olds. Most tumours were of the neuroepithelial type (NBT; n = 671), mainly glioma. The odds ratios (OR) of NBT appeared to decrease with increasing time since start of use of wireless phones, cumulative number of calls and cumulative call time, particularly in the 15-19 years old age group. A decreasing trend in ORs was also observed with increasing estimated cumulative RF specific energy and ELF induced current density at the location of the tumour. Further analyses suggest that the large number of ORs below 1 in this study is unlikely to represent an unknown causal preventive effect of mobile phone exposure: they can be at least partially explained by differential recall by proxies and prodromal symptoms affecting phone use before diagnosis of the cases. We cannot rule out, however, residual confounding from sources we did not measure. Overall, our study provides no evidence of a causal association between wireless phone use and brain tumours in young people. However, the sources of bias summarised above prevent us from ruling out a small increased risk.

Do young adults with childhood asthma avoid occupational exposures at first hire?

Information on the healthy worker hire effect in relation to asthma is scant. We aimed to assess whether and how childhood asthma-related characteristics (before hire) relate to occupational exposures at first hire. Analyses were conducted in 298 children examined at the first survey of the Epidemiological Study on the Genetics and Environment of Asthma (1991-1995), who reported a training period or a job at follow-up in 2003-2007 (aged 17-29 yrs; 53% males). Exposure likelihood to dust, gases and/or fumes in their first occupation was estimated by the ALOHA job exposure matrix. Asthma before the first occupation and two asthma classifications for severity (Global Initiative for Asthma 2002 guidelines) and symptoms were defined by questionnaire. In their first job, 47% of subjects were exposed. After adjustment (age, sex and education), pre-hire onset asthmatics (59%) were nonsignificantly less likely to be exposed (OR 0.67, 95% CI 0.41-1.11). Associations were stronger when considering those with severe asthma or high symptom score in childhood (OR 0.27 (95% CI 0.11-0.63) and OR 0.49 (95% CI 0.25-0.99), respectively). The association was observed in those who completed a university degree (OR 0.55, 95% CI 0.29-1.04) but not in the others (OR 0.98, 95% CI 0.44-2.22), with consistent results for all asthma characteristics. Results suggest a healthy worker hire effect in subjects with more severe or more symptomatic asthma in childhood. Education may modulate self-selection.

Healthy hire effect, job selection and inhalation exposure among young adults with asthma.

The aim of the present study was to assess whether asthma onset prior to entering the workforce influences whether a person holds a subsequent job with asthma-related inhalation exposures. The data of 19,784 adults from the European Community Respiratory Health Survey were analysed. For each respondent, a current or previously held job was linked to a job exposure matrix assigning high, low or no exposure to dust, gases or fumes. Jobs were also categorised according to the risk of exposures related to occupational asthma. Associations between asthma and subsequent occupational exposures were assessed using logistic regression models, with a random intercept for study centre and fixed adjustment for age, sex, type of study sample and smoking status. Of the respondents, 8% (n = 1,619) reported asthma with onset before completion of full-time education. This population was at decreased risk of having a job with high (odds ratio 0.79; 95% confidence interval 0.68-0.92) or low (0.91; 0.80-1.03) exposure to dust, gases or fumes. The associations were consistent across exposure types (dusts, gases or fumes) and for jobs with a high risk of occupational asthma. Adults with asthma onset prior to entering the workforce may be less likely to hold jobs involving inhalation exposures.

The occupational contribution to severe exacerbation of asthma.

The goal of this study was to identify occupational risk factors for severe exacerbation of asthma and estimate the extent to which occupation contributes to these events. The 966 participants were working adults with current asthma who participated in the follow-up phase of the European Community Respiratory Health Survey. Severe exacerbation of asthma was defined as self-reported unplanned care for asthma in the past 12 months. Occupations held in the same period were combined with a general population job-exposure matrix to assess occupational exposures. 74 participants reported having had at least one severe exacerbation event, for a 1-yr cumulative incidence of 7.7%. From regression models that controlled for confounders, the relative risk (RR) was statistically significant for low (RR 1.7, 95% CI 1.1-2.6) and high (RR 3.6, 95% CI 2.2-5.8) biological dust exposure, high mineral dust exposure (RR 1.8, 95% CI 1.02-3.2), and high gas and fumes exposure (RR 2.5, 95% CI 1.2-5.5). The summary category of high dust, gas, or fumes exposure had RR 3.1 (95% CI 1.9-5.1). Based on this RR, the population attributable risk was 14.7% among workers with current asthma. These results suggest occupation contributes to approximately one in seven cases of severe exacerbation of asthma in a working population, and various agents play a role.

Pesticide safety training and practices in women working in small-scale agriculture in South Africa.

OBJECTIVES: Unregulated use of pesticides continues in developing countries in the presence of illiteracy and limited safety training and practices. This paper describes training and safety practices when mixing and spraying pesticides, and acetylcholinesterase levels among women farmers in KwaZulu-Natal, South Africa. METHODS: A cross-sectional study conducted in women working in small-scale agriculture in rural KwaZulu-Natal, South Africa in 2006 assessed pesticide training and safety practices using a questionnaire survey and measured acetylcholinesterase levels in 803 women. Three components of safety behaviour were identified through principle component analysis and described. RESULTS: The mean age of participants was 41.8 years (range 18-82 years) with a mean of 6.9 years (range 1-12 years) of education among school attendees. Among the 803 women included, 366 (45.6%) were the primary sprayers on their farm. Only 16.4% of the sprayers had ever attended a pesticide training course and only 18.0% reported ever reading pesticide labels. Of the women using some form of protective equipment, 56.7% and 54.9% reported doing so when mixing and spraying pesticides, respectively. The mean acetylcholinesterase level corrected for haemoglobin among study participants was 28.9 U/g Hb (95% CI 28.4 to 29.4). CONCLUSION: Women working in small-scale agriculture in rural KwaZulu-Natal with limited access to pesticide training observe few safety practices when mixing and spraying pesticides.

A review of the data quality and comparability of case-control studies of low-level exposure to benzene in the petroleum industry.

PURPOSE: Published case-control studies of risks of leukaemia following low exposures to benzene in the distribution of petroleum (gasoline) have not all identified the same level of risk, but the studies have had differences in cohort inclusion, case determination and availability of occupational and lifestyle data. We reviewed the quality and comparability of the data from three (of four) studies. METHODS: Through site visits, discussions with the investigators and reading study reports, we reviewed and audited the methods used for selecting cases and controls, for estimating individual exposures and for analysing and interpreting the data. Case-control comparisons of exposures were examined using customized graphs. RESULTS: We found that there were no issues of subject selection, methods or general data quality that were likely to have distorted their internal comparisons; we could not check in detail whether the metric for exposure assessments was the same across the studies; the exposure assessments for the Australian study required the least backward estimation, and the Canadian, which also had fewest cases, the most; evidence of an increased risk at higher exposures in Australia was convincing. CONCLUSIONS: The findings are consistent with some effect of benzene at higher lifetime exposures. A proposed pooled analysis should improve quantification of any exposure-response relationship.

Comparison of Two Information Sources for Cause-of-Death Follow-up in the Russian Federation: The Asbest Chrysotile Cohort Study.

BACKGROUND: The Asbest chrysotile cohort was set up in Asbest town, Sverdlovsk oblast, Russian Federation, among the current and former workforce of the world's largest operating chrysotile mine and its processing mills, to investigate cancer risk in relation to occupational exposure to chrysotile. OBJECTIVES: The cohort of 35,837 people was followed-up for mortality using cause-of-death information from official death certificates issued by the Civil Act Registration Office (ZAGS) of Sverdlovsk oblast from 1976 to 2015. Data were also retrieved from the electronic cause-of-death registry of the Medical Information Analytical Centre (MIAC) of Sverdlovsk oblast, which was launched in 1990 and operates independently of ZAGS. The objectives were to compare the completeness of record linkage (RL) with ZAGS and with MIAC, and to compare the agreement of cause-of-death information obtained from ZAGS and from MIAC, with a focus on malignant neoplasms. METHODS: RL completeness of identifying cohort members in ZAGS and in MIAC was compared for the period 1990 to 2015. In the next step, for the comparison of the retrieved cause-of-death information, 5,463 deaths (1,009 from cancer) were used that were registered in 2002 to 2015, when causes of death were coded using International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10) nomenclature by MIAC. For ZAGS, original cause-of-death text from the death certificates was obtained and then coded according to ICD-10 by the International Agency for Research on Cancer/World Health Organization (IARC/WHO). Agreement was evaluated at various levels of detail, and reasons for any disagreements between the MIAC and the IARC/WHO ICD-10-coded cancer diagnosis were systematically explored. RESULTS: A total of 10,886 deaths were obtained from all avenues of follow-up for the period 1990 to 2015 in the cohort; 10,816 (99.4%) of these were found in ZAGS. This percentage was 88.3% if only automated deterministic RL was used and 99.4% when deterministic RL was complemented with manual searches of cohort members. Comparison of the cause-of-death information showed agreement of 97.9% at the ICD-10 main group level between ZAGS (coded by IARC/WHO) and MIAC. Of 1,009 cancer deaths, 679 (67.3%) cases had identical coding, 258 (25.6%) cases corresponded at the three-character ICD-10 level, 36 (3.6%) had codes that were within the same anatomical or morphological cluster, and for only 36 (3.6%) cases were major discrepancies identified. Altogether, the agreement between IARC/WHO coding of cause-of-death information from ZAGS and MIAC coding of malignant neoplasms was therefore 96.4%. CONCLUSIONS: RL completeness and agreement of cause-of-death information obtained from ZAGS and from MIAC were both very high. This is reassuring for the quality of cancer mortality follow-up of the Asbest chrysotile cohort. For future epidemiological studies in the Russian Federation, ZAGS appears to be a reliable information source for mortality follow-up, if the automated RL is complemented with manual searches of cohort members. MIAC is a good resource for prospective studies.

An international prospective general population-based study of respiratory work disability.

BACKGROUND: Previous cross-sectional studies have shown that job change due to breathing problems at the workplace (respiratory work disability) is common among adults of working age. That research indicated that occupational exposure to gases, dust and fumes was associated with job change due to breathing problems, although causal inferences have been tempered by the cross-sectional nature of previously available data. There is a need for general population-based prospective studies to assess the incidence of respiratory work disability and to delineate better the roles of potential predictors of respiratory work disability. METHODS: A prospective general population cohort study was performed in 25 centres in 11 European countries and one centre in the USA. A longitudinal analysis was undertaken of the European Community Respiratory Health Survey including all participants employed at any point since the baseline survey, 6659 subjects randomly sampled and 779 subjects comprising all subjects reporting physician-diagnosed asthma. The main outcome measure was new-onset respiratory work disability, defined as a reported job change during follow-up attributed to breathing problems. Exposure to dusts (biological or mineral), gases or fumes during follow-up was recorded using a job-exposure matrix. Cox proportional hazard regression modelling was used to analyse such exposure as a predictor of time until job change due to breathing problems. RESULTS: The incidence rate of respiratory work disability was 1.2/1000 person-years of observation in the random sample (95% CI 1.0 to 1.5) and 5.7/1000 person-years in the asthma cohort (95% CI 4.1 to 7.8). In the random population sample, as well as in the asthma cohort, high occupational exposure to biological dust, mineral dust or gases or fumes predicted increased risk of respiratory work disability. In the random sample, sex was not associated with increased risk of work disability while, in the asthma cohort, female sex was associated with an increased disability risk (hazard ratio 2.8, 95% CI 1.3 to 5.9). CONCLUSIONS: Respiratory work disability is common overall. It is associated with workplace exposures that could be controlled through preventive measures.

Bayesian modelling of lung cancer risk and bitumen fume exposure adjusted for unmeasured confounding by smoking.

OBJECTIVES: Residual confounding can be present in epidemiological studies because information on confounding factors was not collected. A Bayesian framework, which has the advantage over frequentist methods that the uncertainty in the association between the confounding factor and exposure and disease can be reflected in the credible intervals of the risk parameter, is proposed to assess the magnitude and direction of this bias. METHODS: To illustrate this method, bias from smoking as an unmeasured confounder in a cohort study of lung cancer risk in the European asphalt industry was assessed. A Poisson disease model was specified to assess lung cancer risk associated with career average, cumulative and lagged bitumen fume exposure. Prior distributions for the exposure strata, as well as for other covariates, were specified as uninformative normal distributions. The priors on smoking habits were specified as Dirichlet distributions based on smoking prevalence estimates available for a sub-cohort and assumptions about precision of these estimates. RESULTS: Median bias in this example was estimated at 13%, and suggested an attenuating effect on the original exposure-disease associations. Nonetheless, the results still implied an increased lung cancer risk, especially for average exposure. CONCLUSIONS: This Bayesian framework provides a method to assess the bias from an unmeasured confounding factor taking into account the uncertainty surrounding the estimate and from random sampling error. Specifically for this example, the bias arising from unmeasured smoking history in this asphalt workers' cohort is unlikely to explain the increased lung cancer risk associated with average bitumen fume exposure found in the original study.

Musculoskeletal pain in women working in small-scale agriculture in South Africa.

BACKGROUND: Musculoskeletal pain is associated with demographic, occupational and physical factors. METHODS: Our study investigated the prevalence and factors associated with musculoskeletal pain in 911 women working in small-scale agriculture in rural northern KwaZulu-Natal, South Africa in 2006 using a questionnaire survey. RESULTS: In total, 67% (n = 574) of women reported any chronic musculoskeletal pain. The 12-month prevalence of pain ranged from 63.9% to 73.3% and the prevalence of specific chronic pain lasting more than 3 months ranged from 42.8% to 48.3%. Older age, carrying heavy loads, working with hands above shoulder height, and frequently squatting and kneeling were associated with chronic musculoskeletal pain. CONCLUSION: The prevalence of pain reported in our study, was similar to other developing countries, but considerably higher than in developed countries. Ergonomic interventions including improved and adapted work techniques and tools should be considered to reduce the prevalence of pain in our study population.