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3 PHO Rounds: Understanding the Cold Impacts in Ontario Drs. Ariella Zbar 1 and Hong Chen 1,2,3 November 17, 2015 Public Health Ontario, Canada; 1 Institute for Clinical Evaluative Sciences, Canada; 2 University of Toronto, Canada 3

4 Objectives 1. Understand how cold weather is measured and the basis for extreme cold alerts 2. Describe the adverse health effects of cold and vulnerability to these effects 3. Describe the association between cold weather and adverse health effects in Ontario 4. Identify possible interventions and the role of surveillance in mitigating the effects of cold weather on health Disclosures: none 2

5 Cold weather in Canada Coldest ambient temperature ever recorded: -63⁰C (Snag, YT, 1947) Coldest wind chill ever recorded: -78⁰C (Kugaaruk, NU, 1975) Health Canada. Extreme cold [cited 9 November 2015]. Available from: Photo credit: 3

6 Future trends due to climate change: Warmer winters Less frequent cold extremes: 1 in every 10 years to 1 in every 80 years Adam A. Coldest February on record in Quebec and Ontario. GlobalNews [cited 9 November 2015];. Available from: Toronto Region Conservation Authority. Climate Change -Climate Science -Trends and Forecasts. Toronto: Toronto Region Conservation Authority;. Available from: 4

7 Cold Weather in Ontario Climate Normals, Lester B. Pearson Airport ( ) Number of days where average daily temperature fell within minimum temperature range Min Temp Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total > 0 C <= 2 C <= 0 C < -2 C < -10 C < -20 C < - 30 C Adapted from: Government of Canada. Canadian Climate Normals Station Data. Climate [cited 9 November 2015]. Available from: e.html?stnid=5097&lang=e&station Name=toronto&SearchType=Contains&stnNameSubmit=go&dCode=1 5

8 Cold Alerts: Environment Canada Extreme cold warnings as of April 8 th, 2014 Previously, wind chill warning Now includes air temperature Previously, -40⁰C + light winds might trigger warning, whereas lack of wind = no warning Also includes impact and call-to-action It is recommended to stay indoors. If this is not possible, limit time spent outdoors and exposure to the cold as much as possible to reduce the risk of frostbite and hypothermia. Government of Canada. Public Alerting Criteria. Environment Canada [cited 9 November 2015]. Available from: 6

9 Extreme cold warnings across Ontario Adapted from: -45 C (1)OAC Regions Map. Ontario Arts Council; [cited 9 November 2015]. Available from: files/oac%20regions%20maps%20single%20page%20eng.pdf (2)Government of Canada. Public Alerting Criteria. Environment Canada [cited 9 November 2015]. Available from: En&n=d9553ab5-1#extremeCold -40 C -35 C -30 C 7

10 Wind chill Wind erodes boundary air layer adjacent to skin Increases convective heat transfer Reduces the temperature of exposed skin Sensation that air temperature is lower than measured by thermometer Worsens as temperature drops Wind Speed (km/h) Temperature ( C) Osczevski R. The Basis of Wind Chill. ARCTIC. 1995;48(4). Table adapted from: Government of Canada. Wind Chill Calculator.Environment Canada [cited 9 November 2015]. Available from: 8

11 Wind chill Old measure: plastic cylinders of water at 30m above ground in windy weather in the Antarctic Did not account for internal heat production Did not measure at human height where friction reduces wind speeds by ~66% New measure: facial-cooling model tested on 6 male & 6 female subjects Face used as most exposed and most susceptible to frostbite Found old measure to overestimate wind chill by as much as 20 C Osczevski R. The Basis of Wind Chill. Arctic. 1995;48(4). 9

12 Cold: adverse health effects Non-freezing injuries: trench foot, chilblains, cold urticaria Frostbite: frostnip severe frostbite Hypothermia: Stage 1: body temp drops 1-2⁰C Stage 2: body temp drops 2-4⁰C Quick test: unable to oppose thumb and little finger Stage 3: body temp drops below 32⁰C Risk of death Health Canada. Extreme cold [cited 9 November 2015]. Available from: Fudge J, Bennett B, SimanisJ, Roberts W. Medical Evaluation for Exposure Extremes. Clinical Journal of Sport Medicine. 2015;25(5):

13 Cold: vulnerability heat production Increased risk of cold injury heat loss Impaired thermoregulation Other Conditions worsened by cold Low energy Endocrine disorders Age extremes Low cal intake Inactivity Environment Low body fat Female Age extremes Skin changes Hyperhidrosi s Nervous system disorders Centrally/peripherall y acting meds/drugs EtOH, tobacco Vascular disorders Constrictive clothing Infection Renal failure Previous cold injury Respiratory COPD Asthma Cardiovascul ar CAD CHF Raynaud s Adapted from: Fudge J, Bennett B, SimanisJ, Roberts W. Medical Evaluation for Exposure Extremes. Clinical Journal of Sport Medicine. 2015;25(5):

14 Cold: vulnerability Individual (as per previous slide) Group Age extremes: under 1 year, over 65 Persons experiencing homelessness Outdoor workers Winter sports enthusiasts Neighbourhood Poorly-insulated or poorly-heated homes Homes without power Health Canada. Extreme cold [cited 9 November 2015]. Available from: Government of Canada. Cold Environments. Canadian Centre for Occupational Health and Safety [cited 9 November 2015]. Available from: 12

15 A brief review of current evidence on health effect of cold

16 If further considering cold as a contributing factor, cold may account for an even larger percentage of weather-related deaths 384 cities globally million natural deaths Including 21 Canadian urban centres (9 in Ontario) Gasparrini et al 2015 Lancet

17 If further consider cold as a contributing factor, cold may account for an even larger % of weatherrelated deaths 384 cities globally million natural deaths Including 21 Canadian urban centres (9 in Ontario) Attributable mortality by temperature Total temperatures Cold temperatures Gasparrini et al 2015 Lancet UK 8.8% ( ) 8.5% ( ) USA 5.9% ( ) 5.5% ( ) Canada 5.0% ( ) 4.5% ( ) China 11.0% ( ) 10.4% ( )

18 What do we know about the cold effect on mortality across Ontario? Excess mortality (95% CI) 9% 6% 3% 0% -3% -6% -9% Cold (per 5 o C decrease in temperature) Nonaccidental death Any cardiovascular disease Ischemic heart disease Myocardial infarction CVD-related deaths Heart failure, cardiac arrest and related Stroke All Ontario residents who died between 1996 and 2010 Lived in 27 CDs with temp data Cold significantly increased premature deaths, especially from cardiovascular disease The risk estimates translate to approximately 7 excess deaths per day for each 5 o C decrease in daily mean temperature Chen et al 2015 CMAJ Open (in press) Chen et al 2015 CMAJ Open (in press)

19 What do we know about the cold effect on mortality across Ontario (cont )? Different temperature metrics Total temperatures Cold temperatures UK 8.8% ( ) 8.5% ( ) USA 5.9% ( ) 5.5% ( ) Canada 5.0% ( ) 4.5% ( ) China 11.0% ( ) 10.4% ( ) Estimated excess death from cold (96% CI) * Daily mean air temperature 3.0% (1.8% - 4.2%) Daily mean windchill 1.8% (0.7% - 3.0%) * For each 5 o C decrease Chen et al 2015 CMAJ Open (in press)

20 Please note that we have temporarily removed a few slides presenting unpublished results. Once these results receive peer-review review and get published, we will add these slides back to the presentation. Thanks for your patience!

21 Some remarks Cold is a more important risk factor for morbidity and mortality than most people realize, even in countries with milder winter climates The relationship between cold and human health is complex, with cold effect lasting up to 3 weeks Cold effect persisted throughout most of the year Majority of health burden from cold is related to mild cold because it is far more common To effectively reduce the impact of cold, it is important to incorporate this perspective in future interventions The delay in cold effect offers an opportunity (time window) to prevent clinical outcomes before they occur

22 Interventions: considerations Why? Short and/or long term Who? Ex. cold alert (short term), energy subsidy for low-income families (long term) General population and/or vulnerable groups What? Partnerships Media, law, government incentives 20

23 Short term intervention example: cold alerts Reliable forecast for population and region of interest Understand cause-and-effect relationship between thermal environment and population health outcomes Effective response measures in place to implement within lead-time Involvement of institutions that have sufficient resources, capacity, knowledge and political will to undertake specific response measures HeKovats R, Kristie L. Heatwaves and public health in Europe. The European Journal of Public Health. 2006;16(6): Masato G, Bone A, Charlton-Perez A, CavanyS, Neal R, DankersR et al. Improving the Health Forecasting Alert System for Cold Weather and Heat-Waves In England: A Proof-of-Concept Using Temperature-Mortality Relationships. PLOS ONE. 2015;10(10):e

24 Long term intervention example: energy subsidy Ontario Energy Board Ontario Energy Board. Help for Low-Income Energy Consumers [cited 16 November 2015]. Available from: Income+Energy+Consumers 22

25 Surveillance Cold-related fractures ED attendances, daily minimum temperature (⁰C), daily snow depth (cm): winter ( ) Hughes H, MorbeyR, Hughes T, Locker T, Shannon T, Carmichael C et al. Using an Emergency Department SyndromicSurveillance System to investigate the impact of extreme cold weather events. Public Health. 2014;128(7):

26 Acknowledgements Sarah Li, John Wang, Ray Copes (Public Health Ontario) Eric Lavigne, Richard Burnett, Sabit Cakmak, Abderrahmane Yagouti (Health Canada) Mark Goldberg (McGill University) Antonio Gasparrini (London School of Hygiene & Tropical Medicine) Paul Villeneuve (Carleton University) Funding source: Health Canada and CIHR

27 Thank you