Climate Change and Human Health -How does cold trouble us?

Tiina M Mäkinen, Ph.D. and Juhani Hassi, M.D., Ph.D.Institute of Health Sciences, University of Oulu

Photo: Ilpo Okkonen

Arctic Change 2008Quebec City, 11th December

Outline

Photo:Ilpo Okkonen

Climate changeSymptoms and complaints in coldRespiratory symptoms in coldCold and respiratory tract infectionsFrostbitesConclusions and implications

Climate Change and health impacts (I)

Global warming –will cold remain a health risk?Evidence of reduced cold weather mortality (Carlson et al. 2006) –reflects improvements in social, environmental, behavioral, and health-care factorsExcess winter mortality still much more common than heat related mortalityMore adverse health effects expected due to the aging populationEffects of warming on behavioral adaptation

Climate Change and health impacts (II)

Increased amount of temperature extremesIncrease in minimum and maximum temperatures (McGregor 2006)Heavy precipitation; for example heavy snowfalls increase the amount of heartattacks (Glass 1979, Gorjanc et al. 1999)

Cold exposure common in Arctic areasTemperatures range in the area where cold related adverse health effects are (and will remain) common

Prevalence of cold related complaintsand symptoms:FINRISK 2002 STUDY

Raatikka et al. Int J Biometeorol. 2007

Prevalence of cold related complaints and symptoms

Questionnaire study to 6591 men and women aged 25-74 yrsAlmost all subjects reported at least some cold-related complaintsMost common symptoms/complaints in cold:

Musculoskeletal pain (men 30%/women 27%)Respiratory symptoms: dyspnoea, prolonged cough or cough bouts, wheezing of breath or increased excretion of mucus from the lungs (25% / 29%)Episodic peripheral circulation symptoms (e.g. colourchanges (12% / 15%)Cardiovascular symptoms: chest pain, arrhythmias 3.7%

Raatikka et al. Int J Biometeorol. 2007

Prevalence of cold related complaints and symptoms

Decreased mental or physical performance in cold was reported by 75% of men and 70% of womenFirst symptoms to appear are musculosceletal symptoms (-3°C) and mucus excretion (-5°C), symptoms emerge more commonly at temperatures below-10°C

Raatikka et al. 2007 Int J Biometeorol

Cold exposure and respiratory symptoms in a non-selected population: FINRISK 2002

Harju TH et al. manuscript

Respiratory symptoms in cold

Objective: to determine the occurrence of respiratory symptoms and examine how respiratory diseases affects the prevalenceMethods: Men and women 25-74 yrs old (n=6,951), questionnaire study

Age-adjusted prevalence of respiratory symptoms classified bysmoking, separately for health persons and those reporting a diagnosedlung disease

Harju TH et al.

The prevalenceof respiratorysymptoms in coldis higher in peoplewith a chronic lung disease

Respiratory symptoms in cold

Respiratory symptoms were clearly more common (3-20 x) among asthmatics and in chronic bronchitis compared with healthySputum production and dyspnoea the most common symptoms in coldIn healthy people respiratory symptoms are more common with ageing and appear at higher temperatures

Harju TH et al.

Respiratory symptoms in cold

Cold-induced respiratory symptoms started to emerge at -13.5°C for healthy males and -15.3°C for femalesFor asthma, chronic bronchitis or emphysema the threshold temperatures for respiratory symptoms were higher compared to healthy individuals

Harju TH et al.

Cold and respiratory tract infections

Mäkinen TM et al. Respir Med 2008

Cold and respiratory tract infections

Background: Respiratory tract infections (RTI) are the most common infections worldwide, and a source of significant morbidity. RTIs increase wintertime morbidity. It is estimated that at least 20% of the excess winter mortality is due to respiratory diseases.

Objective:To examine the association between temperature, humidity and respiratory tract infections

Methods:Young conscript during military training (n=892) in northern FinlandDiagnosed respiratory tract infections (RTI), measured ambient average and maximal temperatures, humidity

Mäkinen TM et al. Respir Med 2008

Cold and respiratory tract infections

Temperatures of follow-up period ranged from +30 °C to -30 °CThe mean average daily temperature preceding any RTI was -3.7±10.6°C (n=643), for URTI -4.1±10.6°C (n=595) and LRTI -1.1±10.0°C (n=87) There was a significant decrease in both temperature and humidity during the preceding three days of the onset of an infection

Mäkinen TM et al. Respir Med 2008

Common cold

Lower respiratory tract infection

Mäkinen TM et al. Respir Med 2008

A 1 °C decrease in temperature increased the estimated risk of common cold by 2.1% and pharyngitis by 2.8%

The association between temperature and LRTI was nonlinear

Frostbites in the working life

Photo: Ilpo OkkonenMäkinen et al. manuscript

Frostbites in the working lifeBackground:

The prevalence of frostbites in the working life is not well known. Frostbites is a injury which may cause long term disability

Objective:to determine the prevalence and risk factors of frostbites in the working population

Methods: Questionnaires FINRISK 1997 (n=2624) and 2002 (n=6591)Annual incidence of superficial and severe (blister grade or more severe) frostbiteOccupational factors: physical strain at work/while commuting/leisure time, exposure to cold during winterIndividual factors: diseases, use of alcohol, smoking

Mäkinen et al. manuscript

ResultsAnnually occurring superficial frostbites 13% (330/2550)Annually occurring severe frostbites 1% (95/8788)More common in men than womenCommon in agriculture, stock rising, forestry, industry, students, pensioners, unemployedWork related risk factors: certain occupation, high physical strain at work, high weekly cold exposureIndividual risk factors: diabetes, cardiac insufficiency, angina pectoris, stroke (severe frostbites), white fingers in cold, heavy alcohol use and sensations of depression

ConclusionCold related symptoms and complaints are common in the general populationRespiratory symptoms are more common and appear at higher temperatures among those having a lung diseaseThe prevalence of symptoms and complaints increases in the sick and elderly populationCold temperature and low humidity increases the risk for upper respiratory infectionsFrostbites are relatively common in the general population, health status, behaviour and work-related factors affects the risk

Implications (I)

How can we adapt for the climate change?Physiology, behavior, technologyMeasures:

Protective technologies (housing, transportation, clothing)Weather forecasting associated regional warning systemsHealth warning systems associated public health interventionsPublic-health education and prevention

Implications (II)

Cold related health risk management and prevention should be targeted susceptible population groupsWho are the vulnerable population groups?

People suffering from a chronic diseaseElderly populationPeople frequently involved with cold exposure in their recreational activities or occupations

Participating Institutes:Institute of Health Sciences, University of OuluThe Finnish Defence ForcesDept of Microbiology, University of OuluDept of Internal Medicine, University of OuluNational Public Health Institute, Department of Child and Adolescent HealthThe Finnish Meteorological Institute

Funding: The Finnish Work Environment Fund, The FinnishCultural Foundation

Photo:Ilpo Okkonen