Review of Peel Public Health’s Cold Weather Guideline for Child Care Providers

August 2014

Key findings

 No new peer-reviewed primary research was found on the cold temperature threshold of frostbite.  Source(s) of evidence for recommended cold temperature thresholds in grey literature was not always disclosed or updated.  Research is lacking on risk of extreme cold temperature exposure in children and risk of extreme cold temperatures without wind chill.  Existing research on the temperature threshold associated with cold-related injuries is based on adults. However, many organizations identify children as a vulnerable group at higher risk of cold injury.  The key source of evidence was Environment Canada. However, regional thresholds for cold warnings were not evidence-based. More research is being conducted to understand extreme cold temperature thresholds associated with cold-related injuries.

Background

During the unusually cold winter season in 2013-2014, the Dufferin-Peel Catholic District School Board and concerned parents have contacted Peel Public Health regarding Peel Health’s Cold Weather Guideline for keeping children indoors. The Guideline recommends schools to reduce the amount of time children spend outdoors when the temperature is -20 degrees Celsius or colder (with or without wind chill), and to keep children indoors when the temperature is -25 degrees Celsius or colder (with or without wind chill). Concerns were raised regarding the protectiveness of these thresholds for children, and whether it would pose a health risk. The last revision of the Guideline was conducted in July 2009. A review of the current literature since then was undertaken to obtain any updated evidence specific to the recommended ambient temperature levels to prevent the risk of cold-related injuries such as frostbite, frostnip, chilblain, and hypothermia.

Search Strategy

A search of the peer-reviewed and grey literature was conducted. Medline and Environment Complete databases as well as Health-Evidence.org and the Campbell Collaboration were used to search for peer- reviewed literature published from 2009 onwards. Details of the search strategy are outlined in Appendix 1. Reference lists of relevant review articles were searched to obtain source(s) of evidence. Websites of other health units and key national, provincial and international health agencies were visited to search for grey literature. Environment Canada, Canadian Pediatric Society and Toronto Public Health were contacted for further information. School board websites from several districts were also searched for cold weather policies for comparison. TRIP, Google Scholar, and DuckDuckgo were used to search for any additional peer-reviewed or grey literature. The focus was to determine what the recommended ambient temperature threshold was to prevent health impacts of cold-related injuries such as frostbite and chilblain. The sources of evidence used by these organizations to support their recommendations were identified.

Results

Non-Peer Reviewed Sources

The recommended ambient temperature thresholds to prevent cold-related injuries obtained from various health and safety organizations and associated sources of evidence are summarized in Appendix 2. With the exception of Ottawa Public Health, public health units with a Cold Alert/Advisory system are triggered at -15 degrees Celsius or colder without wind chill or when Environment Canada issues a , and/or predicts extreme weather conditions such as a . The rationale behind the cold alert/advisory temperature threshold of -15 degrees Celsius used by most health units is unknown. The ambient temperature threshold triggering the cold weather alert system in Toronto was based on review of weather conditions that preceded deaths of three homeless people in 1995, average minimum winter temperatures in Toronto, and severe winter weather conditions between 1992 and 1996. Ottawa Public Health issues a Cold Weather Caution when the temperature reaches -15 degrees Celsius or colder for the first time in the winter season. A Frostbite Advisory is issued at a wind chill of -25 or colder and a Frostbite Warning at a wind chill temperature of -35 or colder. At the same time, some health units have recommended that children remain indoors at -25 degrees Celsius or colder (or at wind chill of -28) based on previous recommendations of the Canadian Pediatric Society who later changed their recommendation to reflect Environment Canada’s. Similarly, safety associations have indicated a temperature threshold of -25 degrees Celsius, although the source of evidence was not indicated.

According to Environment Canada, the risk of frostbite or frostnip increases at a wind chill factor of -28 (ambient temperature feels like -28 degrees Celsius) or colder, and if exposed for long periods without adequate protection, the risk of hypothermia occurs at a wind chill of -10 or colder. Health Canada referenced this information on their website. These thresholds were established based on research conducted on troops by the Canadian Department of National Defence (Osczevski and Bluestein, 2005). Additionally, Environment Canada recently replaced the Wind Chill Warning with the Extreme Cold Warning. Call-to-action statements developed in collaboration with Health Canada have indicated vulnerable populations including infants are at greater risk of cold-related injury and require extra attention in protection from the cold. Moving indoors is recommended when cold-related symptoms appear. The threshold temperatures vary by region where the threshold for Southcentral/ is a forecasted temperature of -30 degrees Celsius or colder with or without wind chill for at least 2 hours. To our knowledge, review of regional temperature thresholds by Environment Canada (Morrow, 2014) and the cold alert temperature threshold by Toronto Public Health (Toronto Public Health, 2014) is in progress to ensure that they are evidence-based. Environment Canada is currently looking at the climatology of extreme cold air events across Canada while looking at any research that any health agencies may be conducting on morbidity and mortality associated with cold temperatures. Public Health Ontario is also currently conducting research on the morbidity and mortality of extreme temperatures.

Overall, many websites were focused on providing information on recognizing the symptoms of cold- related injury and general preventative measures required to reduce exposure.

Most school board cold weather policies examined in this review have set cold temperature thresholds at which children should be kept indoors or limited in outdoor activity to be close to Environment Canada’s threshold of frostbite risk or more protective.

Peer-reviewed Sources

No new peer-reviewed primary literature relevant to the general population was found related to recommended ambient threshold temperatures to prevent cold-related injuries. Two articles (a guideline and primary study) were found on risks of cold weather conditions for Olympic athletes and mountain climbers, respectively (Bergeron et al, 2012; Moore and Semple, 2011).

The Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Frostbite (McIntosh et al, 2011) recommended avoiding environmental conditions specifically below -15 degrees Celsius even with low wind speeds to prevent risk of frostbite. This recommendation was based on a re- examination of Siple and Passel’s work (1945) to quantify the risk of frostbite using a cylinder model (Danielsson, 1996).

A review article provided information on epidemiology, clinical presentation and care of frostbite (Kiss, 2012). Based on evidence cited from the US (same evidence source from Environment Canada), frostbite could occur in 30 minutes at -37 degrees Celsius with wind speed of 8 km/h.

Recommendations

 Retain the existing Cold Weather Guideline for keeping children indoors when the temperature or wind chill is at-25 degrees Celsius or colder.  The Guideline should be revised as new research evidence becomes available.  Recommendations of the Guideline assume children are adequately protected from the cold, which should be communicated to child care providers.  The decision to keep children indoors during outdoor play should be at the discretion of child care providers keeping in mind that children may be at higher risk of cold-related injury. Schools may develop in-house policies that may be more protective against extreme cold weather than Peel’s Guideline. Child care providers should monitor that children are adequately dressed for the cold weather conditions.  A detailed information sheet outlining key messages and rationale of the Cold Weather Guideline should be developed for call centre staff in anticipation of future calls from the public.  The Cold Weather Guideline should include the reference source that the extreme cold temperature threshold recommendation is based on (i.e. Environment Canada).

References

Bergeron, MF, Bahr, R, Bӓrtsch, P, et al. (2012). International Olympic Committee consensus statement on thermoregulatory and altitude challenges for high-level athletes. Br J Sports Med, 46: 770-779.

Danielsson, U. (1996). Windchill and the risk of tissue freezing. J Appl Physiol, 81: 2666-2673.

Kiss, TL. (2012). Critical care for frostbite. Critical Care Nursing Clinics of North America, 24(4): 581-591.

McIntosh, SE, Hamonko, M, Freer, L, et al. (2011). Wilderness Medical Society Practice Guidelines for the prevention and treatment of frostbite. Wilderness & Environmental Medicine, 22: 156-166.

Moore, GW and JL Semple. (2011). Freezing and frostbite on Mount Everest: new insights into wind chill and freezing times at extreme altitude. High Altitude Medicine & Biology, 12(3): 271-275.

Morrow, B. Health and Air Quality Program Meteorologist, Meteorological Service of Canada, Environment Canada, Edmonton, , Personal communication via e-mail, June 27, 2014.

Osczevski, R and M Bluestein. (2005). The new wind chill equivalent temperature chart. American Meteorological Society, 86(10): 1453-1458.

Siple, PA and CF Passel. (1945). Measurement of dry atmospheric cooling in subfreezing temperatures. Proc Am Phil Soc, 89: 177-199.

Toronto Public Health. Staff report for action on Cold Weather Protocols in Toronto: Comprehensive review of cold weather protocols and cold weather impacts in Toronto. June 10, 2014.

Appendix 1: Peer-reviewed literature search strategy

PICO question: What is the recommended ambient temperature level at which the risk of developing frostbite, frostnip or chilblain is reduced for children and adults?

Databases searched: Medline, Environment Complete, health-evidence.org, Campbell Collaboration

Medline terms: (“cold temperature [Mesh] AND frostbite/epidemiology, etiology, prevention & control [Mesh]”) OR (“frostbite.ti OR frostnip.ti OR chilblain.ti” AND “cold.ti OR freezing.ti”)

Limits: humans, English language, publication date 2009-current

Citations retrieved: 26

Note: Search terms were adapted to the other databases.

Appendix 2: Review of recommendations from grey literature

Organization Ambient temperature / Wind chill Action/result Source of evidence Notes (year) factor Environment Wind chill of < -27 Risk of frostnip or Based on a 2001 study by Call-to-action statements for Canada (2014) frostbite increases Defence Research & Extreme Cold Warning developed Development (and team of with Health Canada indicate scientist and medical vulnerable groups at greater risk of Temperature or wind chill of < -30 Extreme Cold experts in the US organized frostbite and hypothermia including degrees Celsius expected for at least Warning by the National Weather infants. Recommendation to move 2 hours for Service) indoors if cold-related symptoms Southcentral/Southwestern Ontario. appear. At extreme alert severity, recommendation to stay indoors. Health Canada Wind chill of < -27 Risk of health Environment Canada (2013) effects (windburn, frostbite, hypothermia) increases Canadian Temperature or wind chill of < -27 Keep children Environment Canada Pediatric degrees Celsius indoors Society (2012) Toronto Public Temperature of < -15 degrees Cold weather alert Based on review of weather Recently, transfer of responsibility Health (2014) Celsius (without wind chill) and/or conditions that preceded to issue Cold weather alert to Environment Canada issues wind deaths of three homeless Medical Officer of Health from The chill warning for outdoor activity people in 1995, average Shelter, Support & Housing and/or predicts extreme weather minimum winter Administration made to ensure conditions (e.g. blizzard). temperatures in Toronto, temperature threshold regularly and severe winter weather reviewed based on scientific conditions between 1992 evidence. Consideration being and 1996. made for other weather-related factors such as wind chill, precipitation, sudden drops in temperature, long periods of cold weather.

Halton Region Temperature < -15 degrees Celsius Cold weather alert Source not indicated. Health Unit (without wind chill) or wind chill (2014) reaches level at which Environment Canada issues warning for outdoor activity (-35 degrees Celsius) or extreme weather conditions. Niagara Temperature < -15 degrees Celsius Cold weather alert Canadian Pediatric Society Region Health and/or severe weather conditions Unit (2014) At temperature of < -25 degrees Keep children Celsius or wind chill < -28 indoors Ottawa Public Wind chill < -25 Frostbite advisory Source not indicated. Health (2014) Wind chill < -35 Frostbite warning

First forecasted temperature of < - Cold weather 15 degrees Celsius of the season caution Simcoe- Temperature of < -25 degrees Keep children Canadian Pediatric Society Muskoka Celsius or wind chill < -28 indoors District Health (2014) Ottawa- Wind chill < -25 Keep children Ottawa Public health Carleton indoors (although no source District School indicated for Ottawa Public Board (2013) Health) York Region Temperature or wind chill < -20 Indoor recess Source/rationale not District School degrees Celsius considered indicated. Board (2014) Shortened recess Temperature or wind chill at -18 to - considered 19 degrees Celsius York Catholic Temperature or wind chill of -20 Keep children Source/rationale not District School degrees Celsius indoors indicated, although Board (2013) Environment Canada cited Outdoor break as resource for wind chill Wind chill between -15 and -20 shortened to 20 hazards. degrees Celsius minutes or children remain indoors Toronto Temperature or wind chill of <-28 Keep children Source not indicated, District School degrees Celsius indoors although school principal to Board (2013) consult with Environment Short recess may Canada or Toronto Public Temperature or wind chill of -20 to - be shortened to Health websites for 28 degrees Celsius 10 minutes and information as necessary. lunch recess shortened to 20 minutes Toronto Temperature or wind chill creates Keep children Source not indicated, Catholic risk of frostbite indoors although Environment District School Canada (last update 2003) Board (2004) Halton District Temperature or wind chill of <-20 Keep children Source not indicated. School Board degrees Celsius indoors (2014) Halton Temperature or wind chill of < -20 Keep children Halton Health Department Catholic degrees Celsius indoors District School Board (2014) Temperature or wind chill between - Break can be no 15 and -20 degrees Celsius longer than 20 minutes at a time Wellington Wind chill of -45 (Wind Chill Director will Environment Canada Catholic Warning) consider school School Board closure (2002) Canada Safety Wind chill of -25 Average person’s Defence Research & Council (2009) skin freezes Development Canada Parachute Temperature or wind chill of < -25 Keep children Source not indicated. Canada degrees Celsius indoors (unknown)