Radon exposure and risk of neurodegenerative diseases among male miners in Ontario, Canada: A cohort study.

BACKGROUND: Environmental radon has been examined as a risk factor for neurodegenerative diseases in a small number of previous studies, but the findings have been inconsistent. This study aims to investigate the association between occupational radon exposure and neurodegenerative disease in a cohort of male miners with work experience in multiple ore types in Ontario, Canada. METHODS: Radon exposure (1915-1988) was assessed using two job-exposure matrices (JEM) constructed from using historical records for 34,536 Ontario male miners. Neurodegenerative outcomes were ascertained between 1992 and 2018. Poisson regression models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) between cumulative radon exposure in working level months (WLM) and each neurodegenerative outcome. RESULTS: Levels of cumulative radon exposure showed variability among cohort members with a mean of 7.5 WLM (standard deviation 24.4). Miners in uranium mines or underground jobs had higher levels and more variability in exposure than workers in non-uranium work or surface jobs. Compared to the reference group (radon < 1 WLM), increased rates of Alzheimer's (RR 1.23, 95% CI 1.05-1.45) and Parkinson's disease (RR 1.43, 95% CI 1.08-1.89) were observed among workers with >1-5 WLM and >5-10 WLM, respectively, but not among higher exposed workers (>10 WLM). CONCLUSION: This study did not observe a positive monotonic dose-response relationship between cumulative radon exposure and Alzheimer's or Parkinson's disease in Ontario mining workers. There was no association observed with motor neuron disease.

Silicosis, asbestosis, and pulmonary fibrosis in Ontario, Canada from 1996 to 2019.

BACKGROUND: Silicosis is a fibrotic lung disease caused by exposure to respirable crystalline silica. Historically, silicosis was common among miners and other professions in the 20th century, and in recent decades has re-emerged in coal mining and appeared in new workplaces, including the manufacture of distressed jeans and artificial stone countertops. METHODS: Physician billing data for the province of Ontario between 1992 and 2019 were analyzed across six time-periods (1993-1995, 1996-2000, 2001-2005, 2006-2010, 2011-2015, and 2016-2019). The case definition was two or more billing records within 24 months with a silicosis diagnosis code (ICD-9 502, ICD-10 J62). Cases from 1993 to 1995 were excluded as prevalent cases. Crude incidence rates per 100,000 persons were calculated by time-period, age, sex, and region. Analyses were repeated in parallel for pulmonary fibrosis (PF) (ICD-9 515, ICD-10 J84) and asbestosis (ICD-9 501; ICD-10 J61). RESULTS: From 1996 to 2019, 444 cases of silicosis, 2719 cases of asbestosis and 59,228 cases of PF were identified. Silicosis rates decreased from 0.42 cases per 100,000 in 1996-2000 to 0.06 per 100,000 people in 2016-2019. A similar trend was observed for asbestosis (1.66 to 0.51 per 100,000 persons) but the incidence rate of PF increased from 11.6 to 33.9 per 100,000 persons. Incidence rates for all outcomes were higher among men and older adults. CONCLUSIONS: A decreasing incidence of silicosis was observed in this analysis. However, the incidence of PF increased, consistent with findings from other jurisdictions. While cases of silicosis have been recorded among artificial stone workers in Ontario these cases do not seem to have impacted the population rates thus far. Ongoing, periodic surveillance of occupational diseases is helpful for tracking population-level trends over time.

Artificial intelligence and the work-health interface: A research agenda for a technologically transforming world of work.

The labor market is undergoing a rapid artificial intelligence (AI) revolution. There is currently limited empirical scholarship that focuses on how AI adoption affects employment opportunities and work environments in ways that shape worker health, safety, well-being and equity. In this article, we present an agenda to guide research examining the implications of AI on the intersection between work and health. To build the agenda, a full day meeting was organized and attended by 50 participants including researchers from diverse disciplines and applied stakeholders. Facilitated meeting discussions aimed to set research priorities related to workplace AI applications and its impact on the health of workers, including critical research questions, methodological approaches, data needs, and resource requirements. Discussions also aimed to identify groups of workers and working contexts that may benefit from AI adoption as well as those that may be disadvantaged by AI. Discussions were synthesized into four research agenda areas: (1) examining the impact of stronger AI on human workers; (2) advancing responsible and healthy AI; (3) informing AI policy for worker health, safety, well-being, and equitable employment; and (4) understanding and addressing worker and employer knowledge needs regarding AI applications. The agenda provides a roadmap for researchers to build a critical evidence base on the impact of AI on workers and workplaces, and will ensure that worker health, safety, well-being, and equity are at the forefront of workplace AI system design and adoption.

Occupational Exposure of Canadian Nail Salon Workers to Plasticizers Including Phthalates and Organophosphate Esters.

Personal exposure of nail salon workers to 10 phthalates and 19 organophosphate esters (OPEs) was assessed in 18 nail salons in Toronto, Canada. Active air samplers (n = 60) and silicone passive samplers, including brooches (n = 58) and wristbands (n = 60), were worn by 45 nail salon workers for ∼8 working hours. Diethyl phthalate (median = 471 ng m-3) and diisobutyl phthalate (337 ng m-3) were highest in active air samplers. Most abundant OPEs in active air samplers were tris(2-chloroisopropyl)phosphate or TCIPP (303 ng m-3) and tris(2-chloroethyl)phosphate or TCEP (139 ng m-3), which are used as flame retardants but have not been reported for use in personal care products or nail salon accessories. Air concentrations of phthalates and OPEs were not associated with the number of services performed during each worker's shift. Within a single work shift, a combined total of 16 (55%) phthalates and OPEs were detected on passive silicone brooches; 19 (66%) were detected on wristbands. Levels of tris(2-chloroisopropyl)phosphate, tris(1,3-dichloro-2-propyl)phosphate or TDCIPP, and triphenyl phosphate or TPhP wristbands were significantly higher than those worn by e-waste workers. Significant correlations (p < 0.05) were found between the levels of some phthalates and OPEs in silicone brooches and wristbands versus those in active air samplers. Stronger correlations were observed between active air samplers versus brooches than wristbands. Sampler characteristics, personal characteristics, and chemical emission sources are the three main factors proposed to influence the use of passive samplers for measuring semi-volatile organic compound exposure.

Can Silicone Passive Samplers be Used for Measuring Exposure of e-Waste Workers to Flame Retardants?

Silicone passive samplers were assessed for measuring personal exposure to 37 flame retardants at three Québec e-waste recycling facilities. Silicone brooches (n = 45), wristbands (n = 28), and armbands (n = 9) worn during a ∼8 h work shift accumulated detectable amounts of 95-100% of the target compounds. Brooch concentrations were significantly correlated with those from active air samplers from which we conclude that the brooches could be used to approximate inhalation exposure and other exposures related to air concentrations such as dermal exposure. The generic sampling rate of the brooch (19 ± 11 m3 day-1 dm-2) was 13 and 22 times greater than estimated for home and office environments, respectively, likely because of the dusty work environment and greater movement of e-waste workers. BDE-209 concentrations in brooches and wristbands were moderately and significantly (p < 0.05) correlated with levels in blood plasma; organophosphorus esters in brooches and wristbands were weakly and insignificantly correlated with their metabolite biomarkers in post-shift spot urine samples. Silicone brooches and wristbands deployed over a single shift in a dusty occupational setting can be useful for indicating the internal exposure to compounds with relatively long biological half-lives, but their use for compounds with relatively short half-lives is not clear and may require either a longer deployment time or an integrated biomarker measure.

Neurodegenerative diseases among miners in Ontario, Canada, using a linked cohort.

OBJECTIVES: We examined employment in mining occupations and industries and its association with neurological disease incidence in a linkage cohort from Ontario, Canada. Outcomes included Alzheimer's disease (alone and with other dementias), Parkinson's disease, parkinsonism, motor neuron disease and amyotrophic lateral sclerosis (ALS). METHODS: The Occupational Disease Surveillance System cohort was created by linking workers' compensation data and healthcare usage records. This analysis included over 1.1 million male workers, followed between 1999 and 2016. Neurological diseases were ascertained using physician billing and hospital discharge records. Adjusted Poisson regression models were used to estimate incidence rate ratios (RR) comparing mining to non-mining workers overall and by ore (industry) and occupation group. RESULTS: Suggested elevations in incidence rates were observed for ALS among workers of metal mines (RR 2.21, 95% CI 1.04 to 4.69) and for motor neuron disease among those employed in mining occupations within metal mining industries (RR 1.96, 95% CI 1.01 to 3.79), though these were based on relatively few cases. In miscellaneous metal mines, workers who held mining occupations had an elevated rate of Alzheimer's disease (RR 1.27, 95% CI 0.92 to 1.77). Parkinson's disease rate was elevated among workers with rock and soil drilling occupations (RR 1.60, 95% CI 1.04 to 2.45). CONCLUSIONS: Mining hazards may be associated with elevated rates of neurodegenerative diseases among workers in mining occupations and industries. More work is needed to better understand mining exposures and their associations with neurodegenerative diseases.

Solar ultraviolet radiation exposure among outdoor workers in Alberta, Canada.

BACKGROUND: Outdoor workers are at risk of prolonged and high solar ultraviolet radiation (UVR) exposure, which is known to cause skin cancer. The objectives of this study were to characterize the UVR exposure levels of outdoor workers in Alberta, Canada, and to investigate what factors may contribute to their exposure. METHODS: This study collected objective solar UVR measurements from outdoor workers primarily in Alberta during the summer of 2019. Workers were recruited via the management or health and safety teams from building trade unions and employers. Calibrated, electronic UVR dosimeters were worn by workers on their hardhats, wrists, or lapels for five working days. Data on workers' demographics, jobs, sun protection behaviors, and personal risk factors were collected using questionnaires, and meteorological data for each sampling day were noted. Mean daily exposure measured as the standard erythemal dose (SED) was calculated and compared to the international occupational exposure limit guideline (1.3 SED). Marginal models were developed to evaluate potential determinants of occupational solar UVR exposure. RESULTS: In total, 883 measurements were collected from 179 workers. On average, workerswere exposed to 1.93 SED (range: 0.03-16.63 SED) per day. Just under half of workers (45%) were exposed to levels exceeding the international exposure limit guideline. In the bivariate analyses, landscape and maintenance workers, as well as trade and recreation workers, had the highest levels of exposure (average: 2.64 and 1.84 SED, respectively). Regional variations were observed, with the "other" cities/regions (outside of Edmonton and Calgary) experiencing the highest average levels (2.60 SED). Workers who placed the dosimeters on their hardhats experienced higher levels compared to the other groups. Exposure was highest on sunny and mixed days. Education, trade, city, dosimeter placement, forecast, hair colour, and number of hours outside were included in the final exposure model, of which trade, dosimeter placement, forecast, and number of hours outside at work were statistically significant. CONCLUSIONS: Exposure to elevated solar UVR levels is common among outdoor workers in Alberta. The study findings can help inform future monitoring studies and exposure reduction initiatives aimed at protecting workers.

A scoping review to identify strategies that work to prevent four important occupational diseases.

BACKGROUND: Despite being largely preventable, many occupational diseases continue to be highly prevalent and extremely costly. Effective strategies are required to reduce their human, economic, and social impacts. METHODS: To better understand which approaches are most likely to lead to progress in preventing noise-related hearing loss, occupational contact dermatitis, occupational cancers, and occupational asthma, we undertook a scoping review and consulted with a number of key informants. RESULTS: We examined a total of 404 articles and found that various types of interventions are reported to contribute to occupational disease prevention but each has its limitations and each is often insufficient on its own. Our principal findings included: legislation and regulations can be an effective means of primary prevention, but their impact depends on both the nature of the regulations and the degree of enforcement; measures across the hierarchy of controls can reduce the risk of some of these diseases and reduce exposures; monitoring, surveillance, and screening are effective prevention tools and for evaluating the impact of legislative/policy change; the effect of education and training is context-dependent and influenced by the manner of delivery; and, multifaceted interventions are often more effective than ones consisting of a single activity. CONCLUSIONS: This scoping review identifies occupational disease prevention strategies worthy of further exploration by decisionmakers and stakeholders and of future systematic evaluation by researchers. It also identified important gaps, including a lack of studies of precarious workers and the need for more studies that rigorously evaluate the effectiveness of interventions.

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.

Urinary bisphenol A and incidence of metabolic syndrome among Chinese men: a prospective cohort study from 2013 to 2017.

OBJECTIVES: Experimental studies suggested that bisphenol A (BPA) exposure increased the risk of metabolic syndrome (MetS) through the mechanism of insulin resistance. All previous epidemiological studies of BPA and MetS were cross-sectional studies, and their findings were mixed. This study aims to provide further evidence on the association between urinary BPA and risk of MetS using a prospective cohort study in China. METHODS: The study population was from the Shenzhen Night shift workers' cohort. A total of 1227 male workers were recruited from the baseline survey in 2013 and then followed until 2017. Modified Adult Treatment Panel III criteria were used to identify the cases of MetS. Urinary BPA concentration was assessed using high-performance liquid chromatography-tandem mass spectrometry, and it was categorised into three subgroups by tertiles to obtain the adjusted HR (aHR) and 95% CI using Cox proportional hazard model. RESULTS: During 4 years of follow-up, 200 subjects developed MetS. Compared with the lowest urinary BPA subgroup, a weakly increased risk of MetS was suggested among those with the middle (aHR=1.19, 95% CI 0.87 to 1.63) and high level of urinary BPA (aHR=1.16, 95% CI 0.84 to 1.59); however, the significant association with MetS was restricted primarily to the smokers, showing a positive gradient with urinary BPA (middle level: aHR=2.40, 95% CI 1.13 to 5.08; high level: aHR=2.87, 95% CI 1.38 to 5.98; p trend=0.010). CONCLUSION: This prospective cohort study provided further evidence that exposure to BPA may increase the risk of MetS, and this association was further positively modified by cigarette smoking.

Using health insurance administrative data to explore patch testing utilization in Ontario, Canada-An untapped resource.

BACKGROUND: Patch testing is the key diagnostic test for diagnosing allergic contact dermatitis, but there is limited information on the use of patch testing at the population level. OBJECTIVES: To utilize Ontario Health Insurance Plan (OHIP) data to analyse trends in the rate of patch testing in Ontario. METHODS: Patch testing billing data submitted to the OHIP between 1992 and 2014 were analysed. Two patch test billing codes were investigated: one for work-related testing (G198), and one for non-work-related testing (G206). Rates of patch testing overall were calculated, and trends over time were described. RESULTS: There were 51 576 patch test billings: 48 416 non-work-related and 3160 work-related. The annual rate of non-work-related patch testing (G206) ranged from 11.9 per 100 000 people to 25.9 per 100 000 people, increasing over time. The rate of work-related patch testing (G198) ranged from 0.17 to 2.32 per 1 000 000 people, and was relatively stable. The overall distribution of billing by specialty was 70% dermatology, 19% other medical subspecialties, and 10% paediatrics and family medicine. CONCLUSIONS: Administrative health data can contribute to a more complete understanding of patch test utilization at the population level and, over time, can be used to track patch testing practices.

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.

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.

Workers with hand dermatitis and workplace training experiences: A qualitative perspective.

BACKGROUND: Workplace training may help to prevent contact dermatitis, a common work-related disease. Information on the characteristics of existing workplace training programs and worker perceptions of this training is limited. METHODS: Fourteen workers with suspected occupational contact dermatitis participated in one-on-one, semi-structured interviews. An inductive thematic analysis approach was used to identify interview themes. RESULTS: Workers expressed a desire for hands-on training with content relevant to their job tasks, favored training from supervisors who had practical experience, and were conflicted about employer motivations for providing training. Few workers had received training on skin protection. In many cases, the training workers had received differed greatly from their desired training. CONCLUSIONS: Although, workers with contact dermatitis describe having received workplace training, some question its value and effectiveness. This perspective may be attributed not only to the content and methods of training but also the health and safety culture of the workplace. Am. J. Ind. Med. 60:69-76, 2017. © 2016 Wiley Periodicals, Inc.

Historical occupational isocyanate exposure levels in two Canadian provinces.

Isocyanates such as toluene 2, 4-diisocyanate (TDI), methylene bisphenyl isocyanate (MDI), and hexamethylene diisocyanate (HDI) are known sensitizers and exposure to these chemicals can result in isocyanate-induced asthma-the leading cause of occupational asthma. A newly created exposure database was available containing occupational isocyanate measurements spanning 1981-1996 from Ontario and British Columbia (BC)-two of the largest provinces in Canada. The aim was to describe the historical measurements relative to exposure thresholds, ascertain differences in the data between provinces, and identify time trends. Descriptive statistics of the observations were summarized and stratified by isocyanate species and province. Chi-square tests and Student's t-test were performed to determine differences between provinces. To investigate time trends in the odds of a measurement exceeding the limit of detection (LOD) and time-weighted average (TWA), mixed effects logistic regression models were constructed. In total, 6,984 isocyanate measurements were analyzed, the majority of which were below the LOD (79%). Overall, 8.3% of samples were in excess of the 2014 TLV-TWA of 0.005 ppm. Comparing the two provinces, the proportion of samples exceeding the LOD and TLV-TWA was greater in BC for all isocyanate species. Differences in time trends were also observed between provinces-the odds of a sample exceeding the TLV-TWA decreased over time in the case of MDI (Ontario only), TDI (both Ontario and BC), and other isocyanates (BC only). Our finding that a majority of the exposure measurements was below the LOD is similar to that reported by others. Differences between provinces may be due the fact that isocyanates are classified as a designated substance in Ontario and must adhere to specific exposure control regulations. Limitations of the database, such as finite number of variables and measurements available until 1996 only, presents challenges for more in-depth analysis and generalization of results. An argument is made that a Canadian occupational exposure database be maintained to facilitate risk assessments as well as for occupational epidemiology research.

Urinary metal concentrations among female welders.

As part of a Canada-wide study of women entering non-traditional trades [Women's Health in Apprenticeship Trades-Metalworkers and Electricians (WHAT-ME)], we examined spot urine samples from women welders in Alberta to determine whether urinary metal concentrations exceeded those of the general population, to compare levels to previously published urinary concentrations in male welders and to examine the relationship with welding tasks. Women mailed-in urine samples collected close to the time of completing a detailed exposure questionnaire, including welding tasks on their most recent day welding at work. Of 53 welders working in their trade, 45 had urinary creatinine >0.3-≤3.0g l(-1) and were included in analyses. Seven metals were examined for which both population and male welder urinary concentrations were available: cadmium, chromium, cobalt, copper, manganese, nickel, and zinc. Principal component analysis was used to extract three components from natural log transformed creatinine-corrected metal concentrations. Of the 45 women, 17 reported more than one main task. Overall two thirds worked in fabrication, a third on pipe welding, and smaller numbers on repair, in construction or other tasks: manual metal arc welding was reported by 62%, semi-automatic arc welding by 47%, and arc welding with a tungsten electrode by 15%. In multiple regression analyses, little relation was found between urinary metals and task or type of welding, except for cadmium where lower levels were seen in those reporting semi-automatic manual welding (after adjustment for age and smoking). The proportion of women welders exceeding the selected general population 95th percentile was high for manganese (96%) and chromium (29%). Urinary metal concentrations were similar to those reported for male welders with only manganese, with a geometric mean in women of 1.91 µg g(-1) creatinine, and perhaps copper (11.8 µg g(-1) creatinine), consistently lower in male welders. Although not evident from the task analysis reported here, differences in exposure by sex may be explained by type of welding or by other work practices. A closely comparable cohort of male welders would be necessary to examine this hypothesis more fully.

Association of residential greenness with incident allergic rhinitis among adults: A prospective analysis of UK Biobank.

BACKGROUND: Limited studies have assessed the impact of residential greenness exposure on allergic rhinitis in adults, and its relationship with ambient air pollutants remains unknown. OBJECTIVE: To investigate the association of residential greenness with allergic rhinitis incidence and explore the mediation effects of ambient air pollutants in adults using data from a prospective cohort study in UK Biobank. METHODS: Greenness was defined as the area-weighted mean of greenness coverage based on the land used data from the Generalized Land Use Database for England (GLUD) 2005 in the UK Biobank. Multiple Cox proportional hazard models and a generalized additive model incorporating restricted cubic splines were used to model the potential nonlinear effect of residential greenness on allergic rhinitis incidence and the potential mediation effect of ambient air pollutants. RESULTS: Among the 281,699 subjects included in the analysis, 3260 allergic rhinitis incident cases occurred after a median follow-up of 14 years. With per 10% increase in residential greenness at a 300-m buffer, a 2.5% (95% CI: 1.0%, 4.0%) decreased risk of allergic rhinitis was observed. An L-shaped, non-linear dose-response relationship was indicated with a threshold of 54.9% greenness above which no excess allergic rhinitis risk was seen. PM10 partially mediated the relationship between greenness and allergic rhinitis incidence with a mediation effect of 26.9% (95% CI: 12.6%, 41.2%). A similar pattern of association was found at 1000-m buffer size. CONCLUSION: This study demonstrates a significant beneficial effect of residential greenness on reducing allergic rhinitis incidence. Greenness may erase air pollutants and mitigate the rhinitis risk from air pollution.