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As of January 22, 2020, "disease caused by a novel coronavirus" became a reportable disease of public health significance in Ontario. Public health units were provided with guidance on the entry of patients tested for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the virus causing 2019 coronavirus disease (COVID-19), into the provincial public health information system. Between January 22 and February 22, 2020, there were 359 individuals who had a negative test result recorded and three confirmed cases of COVID-19. Of those who tested negative, 51% were female and 71% were under 50 years of age. The most common symptoms reported were cough (55%), fever (37%) and sore throat (35%). The majority were tested within three days of symptom onset, but over one-quarter tested more than seven days after symptom onset. Over the first month of reportability, reported travel history shifted from China to an increasing proportion with travel outside of China.

Depuis le 22 janvier 2020, la « maladie causée par un nouveau coronavirus » est devenue une maladie à déclaration obligatoire d’importance pour la santé publique en Ontario. Les bureaux de santé publique ont reçu des directives sur la saisie des patients testés pour le coronavirus responsable du syndrome respiratoire aigu sévère (SRAS-CoV-2), le virus causant la maladie à coronavirus 2019 (COVID-19), dans le système provincial d’information sur la santé publique. Entre le 22 janvier et le 22 février 2020, 359 personnes ont reçu un résultat négatif de test et trois cas de COVID-19 ont été confirmés. Parmi les personnes dont le résultat était négatif, 51 % étaient des femmes et 71 % avaient moins de 50 ans. Les symptômes les plus fréquemment signalés étaient la toux (55 %), la fièvre (37 %) et le mal de gorge (35 %). La majorité des personnes ont été testées dans les trois jours suivant l’apparition des symptômes, mais plus d’un quart d’entre elles l’ont été plus de sept jours après. Durant le premier mois de déclaration, les antécédents de voyage déclarés ont passé de la Chine à une proportion croissante de voyages ailleurs qu’en Chine.

Setting Syndemics occur when two or more health conditions interact to increase morbidity and mortality and are exacerbated by social, economic, environmental, and political factors. Routine provincial surveillance in Ontario assesses and reports on the epidemiology of single infectious diseases separately. Therefore, we aimed to develop a method that allows disease overlaps to be examined routinely as a path to better understanding and addressing syndemics in Ontario. Intervention We extracted data for individuals with a record of chlamydia, gonorrhea, infectious syphilis, hepatitis B and C, HIV/AIDS, invasive group A streptococcal disease (iGAS), or tuberculosis in Ontario’s reportable disease database from 1990 to 2018. We transformed the data into a person-based integrated surveillance dataset retaining individuals (clients) with at least one record between 2006 and 2018. Outcomes The resulting dataset had 659,136 unique disease records among 470,673 unique clients. Of those clients, 23.1% had multiple disease records with 50 being the most for one client. We described the frequency of disease overlaps; for example, 34.7% of clients with a syphilis record had a gonorrhea record. We quantified known overlaps, finding 1274 clients had gonorrhea, infectious syphilis, and HIV/AIDS records, and potentially emerging overlaps, finding 59 clients had HIV/AIDS, hepatitis C, and iGAS records. Implications Our novel person-based integrated surveillance dataset represents a platform for ongoing in-depth assessment of disease overlaps such as the relative timing of disease records. It enables a more client-focused approach, is a step towards improved characterization of syndemics in Ontario, and could inform other jurisdictions interested in adopting similar approaches.

The Ontario government implemented a regulatory change to mandate the collection of socio-demographic (SD) data for individuals who tested positive for COVID-19. This change was informed by evidence of COVID-19's disproportionate impact on marginalized communities and calls for broader collection of SD data. Given the scarcity of similar efforts, there is a significant knowledge gap around implementing standardized SD data collection in public health settings.Public Health Ontario provided collaborative support for the implementation of SD data collection, grounded in health equity principles, evidence, and best practices. We supported the addition of SD fields in Ontario's COVID-19 data collection systems, issued data entry guidance, hosted webinars for training and learning exchange, and published a resource to support the data collection process. The current focus is on building sustainability and quality improvement through continued engagement of public health units.By November 28, 2020, almost 80% of COVID-19 cases had information recorded for at least one SD question (individual questions, range 46.8-67.0%). We hosted three webinars for the field, and the data collection resource was viewed almost 650 times. Practitioners continue to express needs for support on applying equity principles to data analysis and interpretation, and community engagement on data collection and use.Sharing knowledge on responsive implementation supports in collaboration with the field and using current evidence and guidance will strengthen public health practice for SD data collection. Laying this groundwork will also improve the likelihood of success and sustainability of these equity-focused efforts.RéSUMé: LIEU: Le gouvernement de l’Ontario a appliqué une modification réglementaire exigeant la collecte de données sociodémographiques (SD) sur les personnes testées positives pour la COVID-19. Cette modification découle des preuves de l’impact disproportionné de la COVID-19 dans les populations marginalisées et appelle à une collecte élargie des données SD. Comme les démarches similaires sont rares, il y a de grandes lacunes au sujet de la mise en œuvre de la collecte de données SD standardisées dans les milieux de la santé publique. INTERVENTION: Santé publique Ontario a collaboré à la mise en œuvre d’une collecte de données SD ancrée dans les principes, les données probantes et les pratiques exemplaires de l’équité en santé. Nous avons appuyé l’ajout de champs SD dans les systèmes ontariens de collecte de données sur la COVID-19, fourni des orientations sur la saisie des données, organisé des webinaires de formation et d’échange de connaissances et publié un document à l’appui du processus de collecte de données. La priorité est actuellement accordée au renforcement de la durabilité et à l’amélioration de la qualité grâce à la participation continue des bureaux de santé publique. RéSULTATS: Au 28 novembre 2020, pour près de 80 % des cas de COVID-19, il existait des informations sur au moins une question SD (questions individuelles, intervalle de 46,8 à 67,0 %). Nous avions organisé trois webinaires pour le personnel de terrain, et notre document sur la collecte de données avait été consulté près de 650 fois. Les praticiens continuent à nous demander de l’aide pour appliquer les principes d’équité à l’analyse et à l’interprétation des données et pour faire participer les communautés à la collecte et à l’utilisation des données. CONSéQUENCES: Le partage des connaissances sur les supports de mise en œuvre adaptés, en collaboration avec le terrain et en faisant appel aux connaissances et aux orientations actuelles, renforcera la collecte de données SD dans la pratique en santé publique. En posant ces bases, nous améliorons aussi les chances de réussite et la durabilité de ces démarches axées sur l’équité.

To determine the Ontario-specific risk of local and travel-related Zika virus transmission in the context of a public health emergency of international concern, Public Health Ontario (PHO) completed a rapid risk assessment (RRA) on January 29, 2016, using a newly developed RRA guidance tool. The RRA concluded that risk of local mosquito-borne transmission was low, with a high risk of imported cases through travel. The RRA was updated 3 times based on predetermined triggers. An independent evaluation assessed both the application of the RRA guidance tool (process evaluation) and the usefulness of the RRA (outcome evaluation). We conducted face-to-face, semi-structured interviews with 7 individuals who participated in the creation or review of the Zika virus RRA and 4 end-users at PHO and the Ministry of Health and Long-Term Care. An inductive thematic analysis of responses was undertaken, whereby themes were directly informed by the data. The process evaluation determined that most steps outlined in the RRA guidance tool were adhered to, including forming a cross-functional writing team, clarifying the scope and describing context, completing the RRA summary report, and updating the RRA based on predefined triggers. The outcome evaluation found that end-users judged the Zika virus RRA as evidence-informed, useful, consistent, and timely. The evaluation established that the locally tailored guidance tool, adapted from national and international approaches to RRAs, facilitated a systematic, evidence-informed, and timely formal RRA process at PHO for the Zika virus RRA, which met the needs of end-users. Based on the evaluation, PHO will modify future RRAs by incorporating some flexibility into the literature review process to support timeliness of the RRA, explicitly describing the limitations of studies used to inform the RRA, and refining risk algorithms to better suit emerging infectious disease threats. It is anticipated that these refinements will improve upon the timely assessment of novel or reemerging infectious diseases.

Background Since 2009, in Ontario, reportable disease surveillance data has been used for timely in-season estimates of influenza severity (i.e., hospitalizations and deaths). Due to changes in reporting requirements influenza reporting no longer captures these indicators of severity, necessitating exploration of other potential sources of data. The purpose of this study was to complete a retrospective analysis to assess the comparability of influenza-related hospitalizations and deaths captured in the Ontario reportable disease information system to those captured in Ontario’s hospital-based discharge database. Methods Hospitalizations and deaths of laboratory-confirmed influenza cases reported during the 2010–11 to 2013–14 influenza seasons were analyzed. Information on hospitalizations and deaths for laboratory-confirmed influenza cases were obtained from two databases; the integrated Public Health Information System, which is the provincial reportable disease database, and the Discharge Abstract Database, which contains information on all in-patient hospital visits using the International Classification of Diseases, 10th Revision, Canada (ICD-10-CA) coding standards. Analyses were completed using the ICD-10 J09 and J10 diagnosis codes as an indicator for laboratory-confirmed influenza, and a secondary analysis included the physician-diagnosed influenza J11 diagnosis code. Results For each season, reported hospitalizations for laboratory-confirmed influenza cases in the reportable disease data were higher compared to hospitalizations with J09 and J10 diagnoses codes, but lower when J11 codes were included. The number of deaths was higher in the reportable disease data, whether or not J11 codes were included. For all four seasons, the weekly trends in the number of hospitalizations and deaths were similar for the reportable disease and hospital data (with and without J11), with seasonal peaks occurring during the same week or within 1 week of each other. Conclusion In our retrospective analyses we found that hospital data provided a reliable estimate of the trends of influenza-related hospitalizations and deaths compared to the reportable disease data for the 2010–11 to 2013–14 influenza seasons in Ontario, but may under-estimate the total seasonal number of deaths. Hospital data could be used for retrospective end-of-season assessments of severity, but due to delays in data availability are unlikely to be timely estimates of severity during in-season surveillance.

Background Ice, or freezing rain storms have the potential to affect human health and disrupt normal functioning of a community. The purpose of this study was to assess acute health impacts of an ice storm that occurred in December 2013 in Toronto, Ontario, Canada. Methods Data on emergency department visits were obtained from the National Ambulatory Care Reporting System. Rates of visits in Toronto during the storm period (December 21, 2013 – January 1, 2014) were compared to rates occurring on the same dates in the previous five years (historical comparison) and compared to those in a major unaffected city, Ottawa, Ontario (geographic comparison). Overall visits and rates for three categories of interest (cardiac conditions, environmental causes and injuries) were assessed. Rate ratios were calculated using Poisson regression with population counts as an offset. Absolute counts of carbon monoxide poisoning were compared descriptively in a sub-analysis. Results During the 2013 storm period, there were 34 549 visits to EDs in Toronto (12.46 per 1000 population) compared with 10 794 visits in Ottawa (11.55 per 1000 population). When considering year and geography separately, rates of several types of ED visits were higher in the storm year than in previous years in both Toronto and Ottawa. Considering year and geography together, rates in the storm year were higher for overall ED visits (RR: 1.10, 95 % CI: 1.09-1.11) and for visits due to environmental causes (RR: 2.52, 95 % CI: 2.21-2.87) compared to previous years regardless of city. For injuries, visit rates were higher in the storm year in both Toronto and Ottawa, but the increase in Toronto was significantly greater than the increase in Ottawa, indicating a significant interaction between geography and year (RR: 1.23, 95 % CI: 1.16-1.30). Conclusions This suggests that the main health impact of the 2013 Ice Storm was an increase in ED visits for injuries, while other increases could have been due to severe weather across Ontario at that time. This study is one of the first to use a population-level database and regression modeling of emergency visit codes to identify acute impacts resulting from ice storms.

Background Negative health outcomes associated with the use of both prescribed and nonprescribed opioids are increasingly prevalent. We examined long-term trends in opioid-related harms in Ontario across a set of 6 indicators and the relation between harms and neighbourhood income in 2016. Methods We examined rates of neonatal abstinence syndrome, opioid poisoning (fatal and nonfatal) and nonpoisoning opioid-related events from 2003 to 2016 in Ontario using population-based health administrative databases. We conducted descriptive analyses for harm indicators across neighbourhood income quintiles in 2016 (2015 for death). We examined social inequalities in opioid-related harms on both relative (prevalence ratio) and absolute (potential rate reduction) scales. Results Rates of opioid-related harms increased dramatically between 2003 and 2016. In 2016, neonatal abstinence syndrome and opioid poisoning and nonpoisoning events showed a strong social gradient, with harm rates being lowest in higher-income neighbourhoods and highest in lower-income neighbourhoods. Prevalence ratios for the lowest-income neighbourhoods compared to the highest-income neighbourhoods ranged from 2.36 (95% confidence interval [CI] 2.15-2.58) for emergency department visits for opioid poisoning to 3.70 (95% CI 2.62-5.23) for neonatal abstinence syndrome. Potential rate reductions for opioid-related harms ranged from 34.8% (95% CI 29.1-40.1) to 49.9% (95% CI 36.7-60.5), which suggests that at least one-third of all harmful events could be prevented if all neighbourhoods had the same socioeconomic profile as the highest-income neighbourhoods. Interpretation Rates of opioid-related harms increased in Ontario between 2003 and 2016, and people in lower-income neighbourhoods experienced substantially higher rates of opioid-related harms than those in higher-income neighbourhoods. This finding can inform planning for opioid-related public health interventions with consideration of health equity.

"INTRODUCTION: Since the early 1990s, researchers have been concerned with the low rate at which women are included in epidemiologic studies of occupational cancer. A previous evaluation determined that one-third of articles published between 1970 and 1990 included women. METHODS: To assess whether there has been an improvement in recent years, papers on occupational cancer between 1991 and 2009 were reviewed in fifteen journals. RESULTS: The proportion of articles that included men remained stable around 90%, while the proportion of articles that included women increased substantially, from 39% in 1991-1995 to 62% in 2006-2009. Articles that assessed risk among men only or men and women presented a higher number of risk estimates and were more likely to evaluate dose-response relationships than studies including women. CONCLUSIONS: Despite advances in the inclusion of women in studies of occupational cancer, disparities remain in the number of studies of occupational cancer and depth of analysis in studies that included women."

OBJECTIVES: The purpose of this study is to describe the impact of the 2016 Zika virus (ZIKV) outbreak on the health-seeking and information-seeking behaviours of Ontarians. METHODS: A timeline that included events and announcements from health agencies was constructed to describe the unfolding of the ZIKV outbreak between January 1 and September 30, 2016. In order to gain an understanding of the information and health-seeking behaviours of Ontarians, data from the following sources were collected and analyzed descriptively over time in 1-week intervals: trends in web searches, calls to a provincial telemedicine advice line, test submissions to the provincial laboratory and Zika-related media coverage. RESULTS: The World Health Organization’s declaration that the ZIKV outbreak was a public health emergency of international concern (PHEIC) prompted a surge in media coverage peaking at 165 articles in a 1-week period. Concurrently, the frequency of Zika-related web searches was at its highest over the time period of the study, weekly telemedicine calls requesting Zika-related information were at their highest (177 calls/week) and requests for laboratory testing increased (162 patients submitting specimens/week). CONCLUSIONS: Understanding the public response to novel and re-emerging infectious disease outbreaks as they unfold has the potential to facilitate timely public messaging for disease prevention, enable resource planning and inform effective public health action.

Purpose To determine the risk of Hodgkin lymphoma (HL) associated with exposures to multiple pesticides grouped by various classes, including carcinogenic classifications. Methods Data collected in the Cross-Canada Study of Pesticides and Health, a population-based incident case–control study in six provinces conducted between 1991 and 1994, were analyzed using unconditional logistic regression. Cases (n = 316) were identified through provincial cancer registries and hospital records. Controls (n = 1,506) were frequency-matched to cases by age (±2 years) within each province and were identified through provincial health records, telephone listings, or voter lists. The Cochran–Armitage test was used to check for trends within pesticide classes. Results Overall, there was an increase in the risk of HL among all subjects who reported use of five or more insecticides (OR 1.88, 95 % CI 0.92–3.87) and among subjects younger than 40 who reported use of two acetylcholinesterase inhibitors (OR 3.16, 95 % CI 1.02–9.29). There was an elevated odds ratio associated with reported use of three or more probably carcinogenic pesticides (OR 2.47, 95 % CI 1.06–5.75), but no increase in risk for use of possibly carcinogenic pesticides. The risk of HL from reported use of fungicides or any pesticides was greater for cases diagnosed before age 40 than for cases diagnosed at or after age 40. When analyses excluded proxy respondents, OR estimates strengthened in some circumstances. Conclusions This study found associations between HL and fungicides, insecticides, specifically acetylcholinesterase inhibitors, and pesticides previously identified as probable human carcinogens. These associations should be further evaluated, specifically in relation to age at diagnosis.

Pesticide exposures and immune suppression have been independently associated with the risk of non-Hodgkin lymphoma (NHL), but their joint effect has not been well explored. Data from a case-control study of men from six Canadian provinces were used to evaluate the potential effect modification of asthma, allergies, or asthma and allergies and hay fever combined on NHL risk from use of: (i) any pesticide; (ii) any organochlorine insecticide; (iii) any organophosphate insecticide; (iv) any phenoxy herbicide; (v) selected individual pesticides [1,1'-(2,2,2-trichloroethylidene)bis[4-chlorobenzene]; 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT), malathion, (4-chloro-2-methylphenoxy)acetic acid (MCPA), mecoprop, and (2,4-dichlorophenoxy)acetic acid (2,4-D); and (vi) from the number of potentially carcinogenic pesticides. Incident NHL cases (n = 513) diagnosed between 1991 and 1994 were recruited from provincial cancer registries and hospitalization records and compared to 1,506 controls. A stratified analysis was conducted to calculate odds ratios (ORs) adjusted for age, province, proxy respondent, and diesel oil exposure. Subjects with asthma, allergies, or hay fever had non-significantly elevated risks of NHL associated with use of MCPA (OR = 2.67, 95% confidence interval [CI]: 0.90-7.93) compared to subjects without any of these conditions (OR = 0.81, 95% CI: 0.39-1.70). Conversely, those with asthma, allergies, or hay fever who reported use of malathion had lower risks of NHL (OR = 1.25, 95% CI: 0.69-2.26) versus subjects with none of these conditions (OR = 2.44, 95% CI: 1.65-3.61). Similar effects were observed for asthma and allergies evaluated individually. Although there were some leads regarding effect modification by these immunologic conditions on the association between pesticide use and NHL, small numbers, measurement error and possible recall bias limit interpretation of these results.

Introduction En milieu de travail, les travailleurs peuvent être exposés à des agents cancérogènes connus ou présumés, dont bon nombre n’ont pas fait l’objet d’une évaluation complète. La recherche sur le cancer d’origine professionnelle a connu une baisse au cours des dernières décennies, et ce, même si les besoins demeurent constants. Le Centre de recherche sur le cancer professionnel (CRCP) a été créé en vue de contrer cette tendance à la baisse en Ontario. Le CRCP a mené une enquête auprès de l’ensemble des intervenants pour connaître les questions prioritaires en matière de recherche sur le cancer d’origine professionnelle. Méthodologie Dans le cadre de l’enquête, le CRCP a reçu 177 réponses provenant d’intervenants du milieu universitaire, du milieu de la santé et de l’industrie, d’intervenants affiliés à des syndicats et de responsables des politiques. Les réponses ont été analysées en fonction de l’exposition en milieu de travail, des emplois à risque et du siège de cancer, et elles ont été stratifiées selon le poste occupé. Résultats Les questions prioritaires soulevées comprennent diverses catégories d’exposition en milieu de travail, notamment les catégories « produits chimiques », « particules et fibres inhalables » (p. ex. amiante), « rayonnements » (p. ex. champs électromagnétiques), « pesticides » et « travail par quarts », ainsi que divers types d’emplois, en particulier les mineurs, les travailleurs de la construction et les travailleurs de la santé. Un financement inadéquat et des données insuffisantes sur l’exposition ont été définis comme les principaux obstacles à la recherche sur le cancer d’origine professionnelle. Discussion Les résultats de cette enquête font ressortir le besoin criant de recherche sur le cancer d’origine professionnelle en Ontario et ailleurs. Ces données seront très utiles pour l’élaboration du programme de recherche du CRCP.

Introduction Workers are potentially exposed to known and suspected carcinogens in the workplace, many of which have not been fully evaluated. Despite persistent need, research on occupational cancer appears to have declined in recent decades. The formation of the Occupational Cancer Research Centre (OCRC) is an effort to counter this downward trend in Ontario. The OCRC conducted a survey of the broad stakeholder community to learn about priority issues on occupational cancer research. Methods The OCRC received 177 responses to its survey from academic, health care, policy, industry, and labour-affiliated stakeholders. Responses were analyzed based on workplace exposures, at-risk occupations and cancers by organ system, stratified by respondents’ occupational role. Results Priority issues identified included workplace exposures such as chemicals, respirable dusts and fibres (e.g. asbestos), radiation (e.g. electromagnetic fields), pesticides, and shift work; and occupations such as miners, construction workers, and health care workers. Insufficient funding and a lack of exposure data were identified as the central barriers to conducting occupational cancer research. Discussion The results of this survey underscore the great need for occupational cancer research in Ontario and beyond. They will be very useful as the OCRC develops its research agenda.

Non-Hodgkin lymphoma (NHL) has been linked to several agricultural exposures, including some commonly used pesticides. Although there is a significant body of literature examining the effects of exposure to individual pesticides on NHL, the impact of exposure to multiple pesticides or specific pesticide combinations has not been explored in depth. Data from a six-province Canadian case-control study conducted between 1991 and 1994 were analyzed to investigate the relationship between NHL, the total number of pesticides used and some common pesticide combinations. Cases (n = 513) were identified through hospital records and provincial cancer registries and controls (n = 1,506), frequency matched to cases by age and province of residence, were obtained through provincial health records, telephone listings, or voter lists. In multiple logistic regression analyses, risk of NHL increased with the number of pesticides used. Similar results were obtained in analyses restricted to herbicides, insecticides and several pesticide classes. Odds ratios increased further when only ‘potentially carcinogenic’ pesticides were considered (OR[one pesticide] = 1.30, 95% CI = 0.90–1.88; OR[two to four] = 1.54, CI = 1.11–2.12; OR[five or more] = 1.94, CI = 1.17–3.23). Elevated risks were also found among those reporting use of malathion in combination with several other pesticides. These analyses support and extend previous findings that the risk of NHL increases with the number of pesticides used and some pesticide combinations.

Since the early 1990s, researchers have been concerned with the low rate at which women are included in epidemiologic studies of occupational cancer. A previous evaluation determined that one-third of articles published between 1970 and 1990 included women.To assess whether there has been an improvement in recent years, papers on occupational cancer between 1991 and 2009 were reviewed in fifteen journals.The proportion of articles that included men remained stable around 90%, while the proportion of articles that included women increased substantially, from 39% in 1991-1995 to 62% in 2006-2009. Articles that assessed risk among men only or men and women presented a higher number of risk estimates and were more likely to evaluate dose-response relationships than studies including women.Despite advances in the inclusion of women in studies of occupational cancer, disparities remain in the number of studies of occupational cancer and depth of analysis in studies that included women.

Objective To assess trends in occupational cancer epidemiology research through a literature review of occupational health and epidemiology journals. Methods Fifteen journals were reviewed from 1991 to 2009, and characteristics of articles that assessed the risk of cancer associated with an occupation, industry, or occupational exposure, were incorporated into a database. Results The number of occupational cancer epidemiology articles published annually declined in recent years (2003 onwards) in the journals reviewed. The number of articles presenting dose–response analyses increased over the review period, from 29% in the first 4 years of review to 49% in the last 4 years. Conclusion There has been a decrease in the number of occupational cancer epidemiology articles published annually during the review period. The results of these articles help determine the carcinogenicity of workplace exposures and permissible exposure limits, both of which may be hindered with a decline in research. Am. J. Ind. Med. 57:259–264, 2014. © 2013 Wiley Periodicals, Inc.

A number of workplace exposures are known to cause cancer. In fact, the workplace has been a major source of information regarding causes of cancer. In most countries, there are sizable public and private efforts to control occupational exposures to minimize disease risks. Despite these considerable and appropriate, preventive efforts, there is relatively little information on their effectiveness. The few studies available do indicate that controlling occupational exposures leads to a reduction in cancer risk. However, details regarding this reduction, e.g., time-dependent changes in risk following intervention and potential confounding and effect modification from other occupational exposures or personal habits, are largely lacking. Such information is needed to identify and characterize successful exposure-reduction approaches and to reduce the cancer burden on our working population in a timely manner.

Objectives Literature documenting the effectiveness of occupational risk-reduction or preventive interventions tends to focus on measuring changes in exposure levels as opposed cancer rates. This systematic review compiles and summarises existing evidence of the impact of asbestos-related interventions on rates of lung cancer, mesothelioma and overall malignancy. Methods A complete review of all literature used by the International Agency for Research on Cancer (IARC) in Monograph 100C and all articles indexed in PubMed since the monograph was completed. Studies were included if they described an asbestos-related intervention or provided risk estimates stratified by time of exposure. Results were analysed using narrative synthesis. Results Of 1094 papers reviewed, nine studies from United States and Canada, United Kingdom, Italy, Germany, Norway and Israel met the inclusion criteria. Interventions included dust reduction efforts such as implementing enclosed or wet processes, discontinuing production, and adopting public policies banning use. Six of eight studies measuring lung cancer reported a decrease in risk after 10–50 years of follow-up and one study reported an overall decrease in malignancy. Only half of studies reporting on mesothelioma observed a decrease in risk over similar time periods. Conclusions There is evidence in the literature that prevention efforts have been effective in decreasing incidence of lung cancer and to a lesser extent mesothelioma. Longer latency periods may partially explain the smaller effect on mesothelioma. These results are informative for projecting future cancer rates and document the benefits of interventions aimed at decreasing asbestos exposure.