Association between outdoor ozone and compensated acute respiratory diseases among workers in Quebec (Canada).

Respiratory effects of ozone in the workplace have not been extensively studied. Our aim was to explore the relationship between daily average ozone levels and compensated acute respiratory problems among workers in Quebec between 2003 and 2010 using a time-stratified case-crossover design. Health data came from the Workers' Compensation Board. Daily concentrations of ozone were estimated using a spatiotemporal model. Conditional logistic regressions, with and without adjustment for temperature, were used to estimate odds ratios (ORs, per 1 ppb increase of ozone), and lag effects were assessed. Relationships with respiratory compensations in all industrial sectors were essentially null. Positive non-statistically significant associations were observed for outdoor sectors, and decreased after controlling for temperature (ORs of 0.98; 1.01 and 1.05 at Lags 0, 1 and 2 respectively). Considering the predicted increase of air pollutant concentrations in the context of climate change, closer investigation should be carried out on outdoor workers.

Effect of summer outdoor temperatures on work-related injuries in Quebec (Canada).

OBJECTIVE: To quantify the associations between occupational injury compensations and exposure to summer outdoor temperatures in Quebec (Canada). METHODS: The relationship between 374,078 injuries compensated by the Workers' Compensation Board (WCB) (between May and September, 2003-2010) and maximum daily outdoor temperatures was modelled using generalised linear models with negative binomial distributions. Pooled effect sizes for all 16 health regions of Quebec were estimated with random-effect models for meta-analyses for all compensations and by sex, age group, mechanism of injury, industrial sector and occupations (manual vs other) within each sector. Time lags and cumulative effect of temperatures were also explored. RESULTS: The relationship between daily counts of compensations and maximum daily temperatures reached statistical significance for three health regions. The incidence rate ratio (IRR) of daily compensations per 1°C increase was 1.002 (95% CI 1.002 to 1.003) for all health regions combined. Statistically significant positive associations were observed for men, workers aged less than 45 years, various industrial sectors with both indoor and outdoor activities, and for slips/trips/falls, contact with object/equipment and exposure to harmful substances/environment. Manual occupations were not systematically at higher risk than non-manual and mixed ones. CONCLUSIONS: This study is the first to quantify the association between work-related injury compensations and exposure to summer temperatures according to physical demands of the occupation and this warrants further investigations. In the context of global warming, results can be used to estimate future impacts of summer outdoor temperatures on workers, as well as to plan preventive interventions.

Summer outdoor temperature and occupational heat-related illnesses in Quebec (Canada).

BACKGROUND: Predicted rise in global mean temperature and intensification of heat waves associated with climate change present an increasing challenge for occupational health and safety. Although important scientific knowledge has been gathered on the health effects of heat, very few studies have focused on quantifying the association between outdoor heat and mortality or morbidity among workers. OBJECTIVE: To quantify the association between occupational heat-related illnesses and exposure to summer outdoor temperatures. METHODS: We modeled 259 heat-related illnesses compensated by the Workers׳ Compensation Board of Quebec between May and September, from 1998 to 2010, with maximum daily summer outdoor temperatures in 16 health regions of Quebec (Canada) using generalized linear models with negative binomial distributions, and estimated the pooled effect sizes for all regions combined, by sex and age groups, and for different time lags with random-effect models for meta-analyses. RESULTS: The mean daily compensation count was 0.13 for all regions of Quebec combined. The relationship between daily counts of compensations and maximum daily temperatures was log-linear; the pooled incidence rate ratio (IRR) of daily heat-related compensations per 1 °C increase in daily maximum temperatures was 1.419 (95% CI 1.326 to 1.520). Associations were similar for men and women and by age groups. Increases in daily maximum temperatures at lags 1 and 2 and for two and three-day lag averages were also associated with increases in daily counts of compensations (IRRs of 1.206 to 1.471 for every 1 °C increase in temperature). CONCLUSION: This study is the first to quantify the association between occupational heat-related illnesses and exposure to summer temperatures in Canada. The model (risk function) developed in this study could be useful to improve the assessment of future impacts of predicted summer outdoor temperatures on workers and vulnerable groups, particularly in colder temperate zones.

Costs of occupational injuries and diseases in Québec.

PROBLEM: Occupational injuries and diseases are costly for companies and for society as a whole. This study estimates the overall costs of occupational injuries and diseases in Québec, both human and financial, during the period from 2005 to 2007. METHOD: The human capital method is used to estimate lost productivity. A health indicator (DALY) is used in combination with a value of statistical life (VSL) to estimate, in monetary terms, the pain and suffering costs resulting from occupational injuries. RESULTS: The costs of occupational injuries and diseases occurring in a single year in Québec are estimated at $4.62 billion, on average, for the 2005-2007 period. Of this amount, approximately $1.78 billion is allocated to financial costs and $2.84 billion to human costs. The average cost per case is $38,355. In view of the limitations identified in the study, it can be argued that this is an underestimation of the costs. Result analysis allows the injury/disease descriptors and industries for which the costs are highest to be identified. PRACTICAL APPLICATIONS: The results of these estimates are a relevant source of information for helping to determine research directions in OHS and prevention. The methodology used can be replicated for the purposes of estimating the costs of injuries and diseases in other populations.

Mortality and cancer incidence in aluminum smelter workers: a 5-year update.

OBJECTIVE: To determine the mortality and cancer incidence of aluminum smelter workers. METHOD: The experience of 17,089 workers between 1950 and 2004 was studied. RESULTS: There were 25 deaths/47 female incident cancers and 6350 deaths/3984 male incident cancers. Mortality was significantly elevated for chronic obstructive pulmonary disease, Alzheimer disease (likely influenced by regional factors), all cancers, stomach, bladder, and lung cancers. Incidence was significantly elevated for bladder, lung, and laryngeal cancers. Digestive, lung, and bladder cancer mortality and lung, bladder, and buccal cancer incidence increased significantly with benzo(a)pyrene (B(a)P) exposure. Over time lung cancer risk has diminished but bladder cancer risk has not. CONCLUSIONS: Bladder cancer incidence was not increased at B(a)P exposures below 40 µg/m·yr. Occupational origins for other cancers occurring above expected rates but probably unrelated to B(a)P exposure cannot be excluded. In the prebake plant, nonsignificant increases of lung cancer were observed between 2000 and 2004.

Estimating occupational exposure to carcinogens in Quebec.

BACKGROUND: We estimated the extent of exposure to occupational carcinogens in Quebec, Canada, to help raise awareness of occupational cancers. METHODS: Proportions of workers exposed to 21 recognized and 17 probable carcinogens (according to Quebec occupational health regulation and the International Agency for Research on Cancer [IARC] classification) were extracted from various sources: workplace monitoring data, research projects, a population survey, radiation protection data, exposure estimates from the Carcinogen Exposure Canada (CAREX Canada) Project database, and published exposure data. These proportions were applied to Quebec labor force data. RESULTS: Among the 38 studied, carcinogens with the largest proportions of exposed workers were solar radiation (6.6% of workers), night shift work/rotating shift work including nights (6.0%), diesel exhaust fumes (4.4%), wood dust (2.9%) and polycyclic aromatic hydrocarbons (2.0%). More than 15 carcinogens were identified in several industrial sectors, and up to 100,000 young workers are employed in these sectors. CONCLUSION: Although crude, estimates obtained with different data sources allow identification of research and intervention priorities for cancer in Quebec.

Identification of workers exposed concomitantly to heat stress and chemicals.

In the context of climate change, concomitant exposure to heat stress and chemicals takes on great importance. However, little information is available in this regard. The purpose of this research, therefore, was to develop an approach aimed at identifying worker groups that would be potentially most at risk. The approach comprises 5 consecutive steps: - Establishment of a list of occupations for all industry sectors - Determination of heat stress parameters - Identification of occupations at risk of heat stress - Determination of exposure to chemicals - Identification of occupations potentially most at risk. Overall, 1,010 occupations were selected due to their representativeness of employment sectors in Québec. Using a rating matrix, the risk stemming from exposure to heat stress was judged "critical" or "significant" for 257 occupations. Among these, 136 occupations were identified as showing a high potential of simultaneous exposure to heat stress and chemicals. Lastly, a consultation with thirteen experts made it possible to establish a list of 22 priority occupations, that is, 20 occupations in the metal manufacturing sector, as well as roofers and firefighters. These occupations would merit special attention for an investigation and evaluation of the potential effects on workers' health.

Climate change and Occupational Health and Safety in a temperate climate: potential impacts and research priorities in Quebec, Canada.

The potential impacts of climate change (CC) on Occupational Health and Safety (OHS) have been studied a little in tropical countries, while they received no attention in northern industrialized countries with a temperate climate. This work aimed to establish an overview of the potential links between CC and OHS in those countries and to determine research priorities for Quebec, Canada. A narrative review of the scientific literature (2005-2010) was presented to a working group of international and national experts and stakeholders during a workshop held in 2010. The working group was invited to identify knowledge gaps, and a modified Delphi method helped prioritize research avenues. This process highlighted five categories of hazards that are likely to impact OHS in northern industrialized countries: heat waves/increased temperatures, air pollutants, UV radiation, extreme weather events, vector-borne/zoonotic diseases. These hazards will affect working activities related to natural resources (i.e. agriculture, fishing and forestry) and may influence the socioeconomic context (built environment and green industries), thus indirectly modifying OHS. From this consensus approach, three categories of research were identified: 1) Knowledge acquisition on hazards, target populations and methods of adaptation; 2) Surveillance of diseases/accidents/occupational hazards; and 3) Development of new occupational adaptation strategies.

Are immigrants, ethnic and linguistic minorities over-represented in jobs with a high level of compensated risk? Results from a Montréal, Canada study using census and workers' compensation data.

OBJECTIVES: Few Canadian data sources allow the examination of disparities by ethnicity, language, or immigrant status in occupational exposures or health outcomes. However, it is possible to document the mechanisms that can create disparities, such as the over-representation of population groups in high-risk jobs. We evaluated, in the Montréal context, the relationship between the social composition of jobs and their associated risk level. METHODS: We used data from the 2001 Statistics Canada census and from Québec's workers' compensation board for 2000-2002 to characterize job categories defined as major industrial groups crossed with three professional categories (manual, mixed, non-manual). Immigrant, visible, and linguistic minority status variables were used to describe job composition. The frequency rate of compensated health problems and the average duration of compensation determined job risk level. The relationship between the social composition and risk level of jobs was evaluated with Kendall correlations. RESULTS: The proportion of immigrants and minorities was positively and significantly linked to the risk level across job categories. Many relationships were significant for women only. In analyses done within manual jobs, relationships with the frequency rate reversed and were significant, except for the relationship with the proportion of individuals with knowledge of French only, which remained positive. CONCLUSIONS: Immigrants, visible, and linguistic minorities in Montréal are more likely to work where there is an increased level of compensated risk. Reversed relationships within manual jobs may be explained by under-reporting and under-compensation in vulnerable populations compared to those with knowledge of the province's majority language.