25/09/2016. Environmental Burden of Disease: What do we really need to worry about? Disclosure. Learning objectives. No conflicts to declare

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1 Environmental Burden of Disease: What do we really need to worry about? Ray Copes, MD Chief, Environmental and Occupational Health, Public Health Ontario Associate Professor, University of Toronto Disclosure No conflicts to declare 2 Learning objectives Describe the methods and findings of previous burden of illness studies. Discuss uses of environmental burden of illness estimates. Apply burden of disease concepts to workplace populations to help guide effective preventive efforts 3 1

2 What is our environment? Macro, micro For a individual, workplace, patients in a medical practice, population (provincial, national, global) Physical environment is one of many factors influencing health 4 Why worry? Because we like to worry? Because we want to take action? But if we want to take action, informed action is likely to lead to better results than uninformed action Good intentions are far more common than good outcomes How can we better understand the problem 5 Risk Assessment A systematic process for describing and quantifying the risk associated with hazardous substances, processes, action, or events from Covelloand MerkhoferRisk Assessment Methods: Approaches for Assessing Health and Environmental Risks 6 2

3 Risk Assessment Often described as 4 step process Scoping or problem formulation often receives little attention This has important implications for the final step of Risk Characterization Although risk assessment are most frequently used in standard setting and compliance; they are probably better suited to comparing (or ranking) risks as a guide to setting priorities Can this be useful tool for setting priorities globally, nationally, for workplaces, practices, individuals? 7 Global burden of disease 1990 (WHO/World Bank Global Burden of Disease) Address lack of data on the contribution of disease, injuries and risk factors to public health 10 risk factors (including air pollution), 107 diseases Concerns about comparability of burden estimates Reliability of measures of effect and exposure estimates from epidemiologic studies used Varying definitions of risk factors between studies Limited data (exposures, outcomes, exposure-outcome relationships) Expert opinion-based weights for disability Lack of standardized methods for risk factor assessment 8 Global burden of disease (2) Global Burden of Disease, WHO (2000) Comparative Risk Assessment module for 25 risk factors Burden from observed risk factor distribution compared to counterfactual scenario 135risk factors (including lead exposure, climate change, urban air pollution and indoor smoke from solid fuels) Updates: 2001, 2002, 2004 (WHO) 9 3

4 What is a disease burden? Mortality Morbidity Pathophysiologic Effects Physiological Effects Exposed 10 Ten leading diseases and injuries Source: Vol 380 December 15/22/29, 2012 Comparison of the magnitude of the ten leading diseases and injuries and the ten leading risk factors based on the percentageofglobal deaths and the percentage of global DALYs, 2010The figure shows 25 total diseases, injuries, and risk factors because some of thelargest contributors to disability-adjusted life years (DALYs) were not in the top ten for deaths, and vice versa. DALYs=disability-adjusted life years. IHD=ischaemic heart disease. LRI=lower respiratory infections. COPD=chronic obstructive pulmonary disease. HAP=household air pollution from solid fuels. BMI=body-mass index. FPG=fasting plasma glucose. PM2.5 Amb=ambient particulate matter pollution. *Tobacco smoking, including second-hand smoke. Physical inac vity and low physical ac vity. Burden of disease attributable to 20 leading risk factors in 2010, expressed percentage of global disability-adjusted life-years as a percentage of global disability-adjusted life-years Both Sexes Source: Lancet. Author manuscript; available in PMC 2014 September 05. NIH-PA 4

5 This is global assessment Helpful for WHO to set global priorities Not as helpful for national or local governments Need to apply at appropriate scale How would the previous Figure look if done for your work force or practice? Individual level tools have been developed and are available ( Can also limit burden of illness assessment to a specific set of factors (e.g. Environment or Workplace) Why Do Environmental Burden of Disease Assessments? 14 Human Health and the Environment are inextricably linked But how? 15 5

6 The beginning of EBD 1981 (Doll & Peto) One of the first attempts to quantify the relationship between risk factors and preventable diseases Estimated preventable US cancer deaths from environmental and lifestyle factors: Cigarette smoking: 30% of all cancer deaths Diet: 35% of cancers Occupational exposures: 4% of cancers Pollution: 2% Doll R, PetoR. The causes of cancer: quantitative estimates of avoidable risks of cancer in the United States today. J NatlCancer Inst Jun; 66 (6): What does the public and policy making community see about the link? Wide array of standards set by multiple jurisdictions and sectors -(e.g. air, water, food, soil) ostensibly set on the basis of protecting human health from environmental exposures. Media coverage of health and environment issues can be informative but often coverage of what s novel rather than normal (the exception rather than the rule) Problem: ad hoc, fragmented, little context. 17 Burden of disease for environmental risk factors Global EBD assessment, WHO (2006) Comparative risk assessment 6 risk factors: Outdoor air pollution Indoor air pollution from solid fuel Lead Water, sanitation and hygiene Climate change Selected occupational risk factors 18 6

7 Outcomes assessed Risk factors Outdoor air pollution Indoor air pollution from solid fuel use Lead Water, sanitation and hygiene Climatechange Selected occupational factors: injuries, noise, carcinogens, airborne particulates Related diseases Cardiovascular mortality, respiratory mortality, mortality from acute respiratory infections in children, lung cancer Lower acute respiratory infections in children, lung cancer, chronic obstructive lung disease (COPD) Intellectual impairment, cardiovascular disease Diarrhoeal diseases, trachoma, schistosomiasis, ascariasis, trichuriasis, hookworm disease Diarrhoeal diseases, malaria, selected unintentional injuries (example from floods), protein-energy malnutrition Unintended injuries, hearing loss, cancers, asthma, COPD, low back pain 19 Country profile of Environmental Burden of Disease Canada Afghanistan Population 32.3 mil 29.9 mil GNI/capita US$ NA % urbanization 80% 49% % people living in cities greater than 100,000 inhabitants 79% 16% Population below the poverty line (national) NA NA Population below the poverty line (international, <$1/day) NA NA Under age 5 mortality rate 6/1000 live births (2006) 257/1000 live births (2006) Life expectancy 81 years (2006) 42 years (2006) Country profile of Environmental Burden of Disease Canada Afghanistan 7

8 Country profile of Environmental Burden of Disease Environmental burden by disease category [DALYs/1000 capita], per year Canada Afghanistan No (2008) NA NA How well are we doing? In many developed countries there has been progress in reducing risks and environmental burden of disease through current approach But. are we directing our efforts to the largest sources of risk? Are our policies and practices effective? Cost-effective? Can we do better? Not without better information? Previous work has been done at the national or local level 23 Previous studies Reference Region Approach Cohen et al(2005) Elliott and Copes (2011) Lucas et al (2008) Stassen et al (2008) Boyd and Genuis (2008) Global BC Global Exposurebased Exposurebased Exposurebased Belgium Exposurebased Canada Outcomebased Results PM 2.5 : 3% of cardiopulmonary deaths, 5% of trachea, bronchus and lung cancer deaths, total 0.8 million premature deaths annually PM 2.5 : 0.2% all-cause mortality among adults Anthropogenic PM 2.5 : 0.93% all-cause mortality among adults UV radiation: 1.6 million DALYs annually Transportation noise: 20,517 DALYs in Flanders in 2004 Total environmental burden of disease: 10,000-25,000 deaths 78, ,000 hospitalizations 8,000-24,000 incident cancers 24 8

9 A modest start Environmental Burden of Cancer for Ontario 25 Environmental burden of disease (EBD) How do we define environment? What would be most useful for policy makers, public, researchers? Information or information for action Attributing current outcomes to past exposures or predicting future outcomes from today s exposures 26 Environmental Burden of Disease Shifts focus from risk to outcomes Does it work? WHO Ontario experience Local issues expected outcomes in a neighbourhood with soil contamination Province wide estimate of BoD- Radon What if we tried to estimate BoDfor all (many?) environmental hazards as a guide to identifying big versus small contributors to adverse health outcomes? 27 9

10 WHO exposure- and scenario-based methods Exposure-based approach - Identify outcomes associated with risk factor - Distribution of exposure in population - Exposure-response relationship - Calculate distribution of health impacts Exposure Exposure-response relationship Outcomes Scenario-based approach - Identify outcomes associated with risk factor - Defined exposure scenarios for population - Exposure-response relationship - Calculate distribution of health impacts 28 WHO outcome-based method Outcome-based approach - Identify outcomes associated with risk factor - Distribution of outcomes in population - Determination and definition of attributable fraction for risk factor - Calculate attributable fraction Exposure Exposureresponse relationship Outcomes 29 Environmental Burden of Cancer in Ontario PHO Grand Rounds August 9, 2016 Ray Copes, Sue Greco Public Health Ontario Stephanie Young Cancer Care Ontario 10

11 a. Selected environmental carcinogens 31 Results reflect: 1. EXPOSURE Current (2010) levels of exposure Exposure across a lifetime Population-, not individual-, level exposures No threshold assumption 2. POTENCY Underlying studies to develop potency estimates cancercare.on.ca/environmentreport publichealthontario.ca/environmentalcancer environmental carcinogens relevant to Ontario population COMBUSTION BY- PRODUCTS Fine particulate matter (PM 2.5 ) Diesel engine exhaust Polycyclic aromatic hydrocarbons (PAHs) Second-hand smoke (SHS) 2,3,7,8-Tetrachlorodibenzo-dioxin (dioxin) METALS OTHER Arsenic Cadmium Chromium Nickel Acrylamide Asbestos Polychlorinated biphenyls (PCBs) VOLATILE ORGANIC COMPOUNDS (VOCs) 1,2-Dichloropropane 1,3-Butadiene Chlorinated toluenes Benzene Dichloromethane Formaldehyde Tetrachloroethylene (PCE) Trichloroethylene (TCE) Vinyl chloride RADIATION Radon Solar ultraviolet (UV) radiation 33 11

12 b. Considered multiple routes of exposure 34 c. Developed exposure estimates from a variety of data sources Exposures based on carcinogen concentrations in indoor air, outdoor air, food, drinking water, and dust Data sources ranged from provincial monitoring campaigns to population-based surveys and individual studies Current exposure estimates applied across a lifetime 35 d. Used two models to estimate the environmental burden of cancer Model Risk Assessment Population Attributable Fraction (PAF) Estimates: Excess cases Fraction of cases Function of: Exposure Potency Number exposed Attributable fraction (influenced by exposure and potency/relative risk) Number of cancer cases (site specific) Number

13 Environmental burden of cancer dominated by 3 Heat map for each carcinogen and route of exposure Reducing the Environmental Burden of Cancer Exposure can be reduced through legislation and public policy Requires coordinated efforts among complex technical, environmental, health and social systems Solutions demand an integrated whole-of-government approach and cooperation by the private sector, nongovernmental organizations and individual citizens cancercare.on.ca/environmentreport publichealthontario.ca/environmentalcancer 39 13

14 Take-home messages There have been some past successes in reducing exposures (e.g. second hand smoke) Opportunity to tackle current exposures of public health significance Three carcinogens contributed to over 90% of the environmental burden of cancer in Ontario UV (from sunlight) Radon (from indoor air) PM 2.5 (from outdoor air) cancercare.on.ca/environmentreport publichealthontario.ca/environmentalcancer 40 Take-home messages There have been some past successes in reducing exposures (e.g. second hand smoke) Opportunity to tackle current exposures of public health significance Three carcinogens contributed to over 90% of the environmental burden of cancer in Ontario UV (from sunlight) Radon (from indoor air) PM 2.5 (from outdoor air) But need to distinguish between attributable and preventable! cancercare.on.ca/environmentreport publichealthontario.ca/environmentalcancer 41 Environmental burden of cancer falls between burdens of alcohol and smoking Overall burden is 4,800 (range: 3,540 to 6,510) new cancer cases each year in Ontario from exposure to these 23 carcinogens 6% (range: 4 to 8%) of all new cases in Ontario (2011) Results dominated by a few carcinogens, with burden for half of carcinogens over 10 cancers per year Generally consistent with but more detailed than past estimates cancercare.on.ca/environmentreport publichealthontario.ca/environmentalcancer 42 14

15 43 Thank You 44 15