Gender Differences in Surgery for Work-Related Musculoskeletal Injury: A Population-Based Cohort Study.

OBJECTIVE: The objective of this study is to examine if women are less likely than men to receive surgery following work-related musculoskeletal injury in the Canadian province of British Columbia. METHODS: The study included 2,403 workers with work-related knee meniscal tear, thoracic/lumbar disc displacement or rotator cuff tear. Probability of surgery was compared by gender using Kaplan-Meier methods and Cox proportional hazards models. RESULTS: For each injury type, a smaller proportion of women received surgery compared to men (knee: 76% vs. 80%; shoulder: 13% vs. 36%; back: 13% vs. 19%). In adjusted models, compared to men, women were 0.87 (95% confidence interval [CI] [0.69, 1.09]), 0.35 (95% CI [0.25, 0.48]) and 0.54 (95% CI [0.31, 0.95]) times less likely to receive knee, shoulder or back surgery, respectively. CONCLUSIONS: Probability of surgery following work-related musculoskeletal injury was lower for women than for men. Strategies to ensure gender equitable delivery of surgical services by workers' compensation systems may be warranted, although further research is necessary to investigate determinants of the gender difference and the impact of elective orthopaedic surgery on occupational outcomes.

Dermatitis among workers in Ontario: results from the Occupational Disease Surveillance System.

OBJECTIVES: Dermatitis is the most common occupational skin disease, and further evidence is needed regarding preventable risk factors. The Occupational Disease Surveillance System (ODSS) derived from administrative data was used to investigate dermatitis risk among industry and occupation groups in Ontario. METHODS: ODSS cohort members were identified from Workplace Safety and Insurance Board (WSIB) accepted lost time claims. A case was defined as having ≥2 dermatitis physician billing claims during a 12-month period within 3 years of cohort entry. A 3-year look-back period prior to cohort entry was used to exclude prevalent cases without a WSIB claim. Workers were followed for 3 years or until dermatitis diagnosis, age 65 years, emigration, death or end of follow-up (31 December 2016), whichever occurred first. Age-adjusted and sex-adjusted Cox proportional hazard models estimated HRs and 95% CIs. The risk of dermatitis was explored using a job exposure matrix that identifies exposure to asthmagens, many of which also cause contact dermatitis. RESULTS: Among 597 401 workers, 23 843 cases of new-onset dermatitis were identified. Expected elevated risks were observed among several groups including furniture and fixture industries, food and beverage preparation and chemicals, petroleum, rubber, plastic and related materials processing occupations and workers exposed to metal working fluids and organic solvents. Decreased risk was observed among farmers, nurses and construction industries, and occupations exposed to latex and indoor cleaning products. CONCLUSIONS: ODSS can contribute to occupational dermatitis surveillance in Ontario by identifying occupational groups at risk of dermatitis that can then be prioritised for prevention activities.

The impact of night shift work on breast cancer: Results from the Burden of Occupational Cancer in Canada Study.

BACKGROUND: We estimated the proportion and number of female breast cancer cases in Canada attributable to night shift work, a probable cause of breast cancer. METHODS: Levin's equation was used to calculate population attributable fractions (PAFs) among Canadian women who ever worked night/rotating shifts from 1961 to 2000, accounting for labor turnover and survival to the year 2011. The calculated PAFs were applied to 2011 Canadian breast cancer incidence statistics to obtain the number of attributable cases. RESULTS: Approximately 1.5 million women ever worked night/rotating shifts during 1961-2000 and survived to 2011. The PAFs ranged from 2.0% (95% confidence interval [CI]: 1.4-6.2) to 5.2% (95% CI: 3.7-13.6), and 470 to 1200 incident breast cancer cases in 2011 were likely due to shift work, of which 38% would have been diagnosed among women in health-related occupations. CONCLUSIONS: More research is needed to increase the certainty of this association, but current evidence supports workplace-based prevention.

Prostate cancer risk by occupation in the Occupational Disease Surveillance System (ODSS) in Ontario, Canada. / Risque de cancer de la prostate par profession dans le Système de surveillance des maladies professionnelles de l'Ontario, Canada.

INTRODUCTION: Previous Canadian epidemiologic studies have identified associations between occupations and prostate cancer risk, though evidence is limited. However, there are no well-established preventable risk factors for prostate cancer, which warrants the need for further investigation into occupational factors to strengthen existing evidence. This study uses occupation and prostate cancer information from a large surveillance cohort in Ontario that linked workers' compensation claim data to administrative health databases. METHODS: Occupations were examined using the Occupational Disease Surveillance System (ODSS). ODSS included 1 231 177 male workers for the 1983 to 2015 period, whose records were linked to the Ontario Cancer Registry (OCR) in order to identify and follow up on prostate cancer diagnoses. Cox proportional hazard models were used to calculate age-adjusted hazard ratios and 95% CI to estimate the risk of prostate cancer by occupation group. RESULTS: A total of 34 997 prostate cancer cases were diagnosed among workers in ODSS. Overall, elevated prostate cancer risk was observed for men employed in management/ administration (HR 2.17, 95% CI = 1.98-2.38), teaching (HR 1.99, 95% CI = 1.79-2.21), transportation (HR 1.20, 95% CI = 1.16-1.24), construction (HR 1.09, 95% CI = 1.06-1.12), firefighting (HR 1.62, 95% CI = 1.47-1.78), and police work (HR 1.20, 95% CI = 1.10-1.32). Inconsistent findings were observed for clerical and farming occupations. CONCLUSION: Associations observed in white collar, construction, transportation, and protective services occupations were consistent with previous Canadian studies. Findings emphasize the need to assess job-specific exposures, sedentary behaviour, psychological stress, and shift work. Understanding specific occupational risk factors can lead to better understanding of prostate cancer etiology and improve prevention strategies.

The current burden of cancer attributable to occupational exposures in Canada.

Exposure to occupational carcinogens is often overlooked as a contributor to the burden of cancer. To estimate the proportion of cancer cases attributable to occupational exposure in Canada in 2011, exposure prevalence and levels of 44 carcinogens were informed by data from the Canadian carcinogen exposure surveillance project (CAREX Canada). These were used with Canadian Census (between 1961 and 2011) and Labour Force Survey (annual surveys between 1976 and 2013) data to estimate the number of workers ever exposed to occupational carcinogens. Risk estimates of the association between each carcinogen and cancer site were selected mainly from published literature reviews. Population attributable risks were estimated using Levin's equation and applied to the 2011 cancer statistics from the Canadian Cancer Registry. It is estimated that 15.5 million Canadians alive in 2011 were exposed, during at least one year between 1961 and 2001, to at least one carcinogen in the workplace. Overall, we estimated that in 2011, between 3.9% (95% CI: 3.1%-8.1%) and 4.2% (95% CI: 3.3%-8.7%) of all incident cases of cancer were due to occupational exposure, corresponding to lower and upper numbers of 7700-21,800 cases. Five of the cancer sites - mesothelioma, non-melanoma skin cancer, lung, female breast, and urinary bladder - account for a total of 7600 to 21,200 cancers attributable to occupational exposures such as solar radiation, asbestos, diesel engine exhaust, crystalline silica, and night shift work. Our study highlights cancer sites and occupational exposures that need recognition and efforts by all stakeholders to avoid preventable cancers in the future.

Adult Asthma among Workers in Ontario. Results from the Occupational Disease Surveillance System.

Rationale: Given that approximately 15% of new-onset adult asthma cases originate because of exposures in the workplace, there is a need for systematic and ongoing monitoring of risk among workers. Objectives: To characterize the risk of new-onset adult asthma among workers in Ontario. Methods: We used 575,379 provincial accepted time-loss workers' compensation claimants data linked to physician billing data. Workers aged 15 to 65 years with a nonasthma compensation claim between January 1, 2002, and December 31, 2013, were eligible for inclusion. Cohort entry corresponded to the date of the claim. The case definition required two or more records for asthma within a 12-month period, within a 3-year time window after cohort entry. A 3-year washout period preceding cohort entry was used to exclude prevalent cases. Workers at risk of new-onset adult asthma were followed from cohort entry date to date of diagnosis, emigration, age 65 years, death, or end of study period. Cox regression models were used to generate birth year- and sex-adjusted hazard ratios (HRs) by occupation, industry, and exposures identified using a job exposure matrix. Sex-stratified risk estimates were also generated. Results: Increased risks were detected among well-recognized groups, including bakers (HR, 1.60; 95% confidence interval [CI], 1.22-2.09) and painters and decorators (HR, 1.67; 95% CI, 1.23-2.28). In the job exposure matrix analysis, flour and isocyanates were associated with increased risk of asthma. Concrete finishers (HR, 1.93; 95% CI, 1.12-3.32) and shipping and receiving clerks (HR, 1.21; 95% CI, 1.03-1.43) also showed elevated risk, whereas results varied across woodworker groups. Decreased risks were detected for nursing and farming groups. Conclusions: This practical data linkage approach was successful for examining associations across hundreds of jobs. Unexpected and previously unrecognized findings deserve further investigation and emphasize the importance of an ongoing system to guide research as well as prevention.

Examining lung cancer risks across different industries and occupations in Ontario, Canada: the establishment of the Occupational Disease Surveillance System.

BACKGROUND: The Occupational Disease Surveillance System (ODSS) was established in Ontario, Canada by linking a cohort of workers with data created from Workplace Safety and Insurance Board (WSIB) claims to administrative health databases. The aim of this study was to use ODSS to identify high-risk industry and occupation groups for lung cancer in Ontario. METHODS: Workers in the WSIB lost time claims database were linked to the Ontario Cancer Registry using subjects' health insurance numbers, name, sex, birthdate and death date (if applicable). Several occupations and industries known to be at increased risk were outlined a priori to examine whether ODSS could replicate these associations. Age-adjusted, sex-stratified Cox proportional hazard models compared the risk of lung cancer within one industry/occupation versus all other groups in the cohort. Workers with a lung cancer diagnosis prior to cohort entry were excluded for analysis, leaving 2 187 762 workers for analysis. RESULTS: During the 1983 to 2014 follow-up, 34 661 workers in the cohort were diagnosed with lung cancer. Among expected high-risk industries, elevated risks were observed among workers in quarries/sand pits and construction industries for both sexes, and among males in metal mines, iron foundries, non-metallic mineral products industries and transportation industries. Excess risk was also observed among occupations in drilling/blasting, other mining/quarrying, mineral ore treating, excavating/grading/paving, truck driving, painting, bus driving and construction. CONCLUSIONS: This current surveillance system identified several established high-risk groups for lung cancer and could be used for ongoing surveillance of occupational lung cancer in Ontario.

Burden of lung cancer attributable to occupational diesel engine exhaust exposure in Canada.

OBJECTIVE: To estimate the population attributable fraction (PAF) and number of incident and fatal lung cancers in Canada from occupational exposure to diesel engine exhaust (DEE). METHODS: DEE exposure prevalence and level estimates were used with Canadian Census and Labour Force Survey data to model the exposed population across the risk exposure period (REP, 1961-2001). Relative risks of lung cancer were calculated based on a meta-regression selected from the literature. PAFs were calculated using Levin's equation and applied to the 2011 lung cancer statistics obtained from the Canadian Cancer Registry. RESULTS: We estimated that 2.4% (95% CI 1.6% to 6.6%) of lung cancers in Canada are attributable to occupational DEE exposure, corresponding to approximately 560 (95% CI 380 to 1570) incident and 460 (95% CI 310 to 1270) fatal lung cancers in 2011. Overall, 1.6 million individuals alive in 2011 were occupationally exposed to DEE during the REP, 97% of whom were male. Occupations with the highest burden were underground miners, truck drivers and mechanics. Half of the attributable lung cancers occurred among workers with low exposure. CONCLUSIONS: This is the first study to quantify the burden of lung cancer attributable to occupational DEE exposure in Canada. Our results underscore a large potential for prevention, and a large public health impact from occupational exposure to low levels of DEE.

Surveillance of mesothelioma and workers' compensation in British Columbia, Canada.

OBJECTIVES: To determine the rate of workers' compensation for mesothelioma cases in the Canadian province of British Columbia, examine trends in mesothelioma cases and compensation over time, and identify factors associated with compensation status for mesothelioma cases. METHODS: Mesothelioma cases in the provincial cancer registry were linked at the individual level with accepted claims for mesothelioma in the provincial workers' compensation system for the period 1970-2005. RESULTS: 391 of the 485 workers' compensated claims were linked (81% match rate) with a record in the cancer registry for an overall mesothelioma compensation rate of 33% over the study period and a high of 49% in the last 5 years. Compensation rates were lower for women, older (retired) as well as younger workers, and sites other than the pleura. CONCLUSIONS: Although the workers' compensation rate for mesothelioma increased over time, the rate was much lower than anticipated for cases believed to be work-related cancers. Several key factors may significantly influence awareness by clinicians and workers of the work-relatedness of mesothelioma and of workers' compensation benefits. Regulatory agencies need to develop policies or effective notification systems to ensure that all newly diagnosed mesothelioma cases seek compensation benefits.

Do private clinics or expedited fees reduce disability duration for injured workers following knee surgery?

OBJECTIVE: To investigate the effect of workers' compensation policies related to expedited surgical fees and private clinic surgical setting on disability duration among injured workers. METHODS: The study included 1,380 injured workers with knee meniscectomy between 2001 and 2005 in British Columbia. Using linked workers' compensation claim and surgery/clinical records, wait time for surgery (time from last surgical consult to surgery) and time from surgery to return to work were computed and compared for workers who received care in public versus private facilities, and according to whether their surgeons received fees intended to expedite care. RESULTS: The public expedited group had the shortest disability duration from surgical consult to return to work; the expedited fee reduced the surgery wait time (~2 work weeks), and surgeries performed in public hospitals had a shorter return-to-work time (~1 work week). DISCUSSION: An overall difference of approximately three work weeks in disability duration may have meaningful clinical and quality-of-life implications for injured workers. However, minimal differences in expedited surgical wait times by private clinics versus public hospitals, and small differences in return-to-work outcomes favouring the public hospital group, suggest that a future economic evaluation of workers' compensation policies related to surgical setting is warranted.

Research opportunities using administrative databases and existing surveys for new knowledge in occupational health and safety in Canada, Quebec, Ontario and British Columbia.

In Canada, many datasets are initially collected for purposes other than occupational health and safety (OHS) research. These include administrative health care billing records, pharmaceutical records, vital statistics, provincial cancer registries and workers' compensation claims data. In addition, many national and provincial health surveys, while not focused specifically on occupational health and safety, collect data on the health status and health determinants of populations, and such data can be used for investigating OHS issues among Canadian workers. This paper provides examples of the use of administrative and survey data for OHS research projects from the provinces of Quebec, Ontario and British Columbia to illustrate the potential of such data. These three provinces have a long history of using administrative and survey data for OHS research and have developed capacity in this regard for improving access to data, for linkage of records across databases and for developing methods to answer OHS questions. As research using these data sources expands, a consistent understanding within the work and health research community must be forged concerning the strengths and limitations of these data resources and their comparability.

Sociodemographic, clinical, and work characteristics associated with return-to-work outcomes following surgery for work-related knee injury.

OBJECTIVE: This study examined the association between return-to-work (RTW) outcomes and sociodemographic, clinical, and work characteristics among a cohort of injured workers who underwent knee surgery between 2001-2005 in British Columbia, Canada. METHODS: Workers' compensation databases were used to identify the retrospective cohort and abstract the study variables. Multinomial logistic regression provided odds ratios (OR) and 95% confidence intervals (95% CI) for the association between RTW (unspecified, partial, full, or non-RTW) and the independent variables. RESULTS: Data was abstracted for 1394 injured workers. Compared to men, women were more likely to have partial RTW (OR 2.55, 95% CI 1.53-4.23) and non-RTW (OR 2.61, 95% CI 1.35-5.03) than full RTW; low income earners were more likely than high income earners to have partial RTW (OR 3.05, 95% CI 1.86-4.99) and non-RTW (OR 4.07, 95% CI 2.19-7.57). Moreover, workers in trade, primary resource, and processing/manufacturing occupations were more likely than those in management occupations to have non-RTW than full RTW by the end of follow-up (OR 2.97, 95% CI 1.32-6.68; OR 9.31, 95% CI 3.41-25.41, and OR 2.71, 95% CI 1.07-6.5, respectively). Surgical and clinical factors were not associated with RTW outcomes. CONCLUSIONS: Using population-based data, our study found a link between sociodemographic and work characteristics and the type of RTW outcome following knee surgery for a work-related injury. Women and lower income earners tended not to have full RTW, after controlling for covariates. Workers in physically demanding occupations also tended not to have full RTW, suggesting that factors beyond clinical and surgical characteristics influence disability outcomes. RTW programs need to take into consideration these broader determinants of worker health.