title: Susceptibility to mortality related to temperature and heat and cold wave duration in the population of Stockholm County, Sweden.
abstract: BACKGROUND
  Ambient temperatures can cause an increase in mortality. A better understanding is needed of how health status and other factors modify the risk associated with high and low temperatures, to improve the basis of preventive measures. Differences in susceptibility to temperature and to heat and cold wave duration are relatively unexplored.
  
  
  OBJECTIVE
  We studied the associations between mortality and temperature and heat and cold wave duration, stratified by age and individual and medical factors.
  
  
  METHODS
  Deaths among all residents of Stockholm County between 1990 and 2002 were linked to discharge diagnosis data from hospital admissions, and associations were examined using the time stratified case-crossover design. Analyses were stratified by gender, age, pre-existing disease, country of origin, and municipality level wealth, and adjusted for potential confounding factors. Results : The effect on mortality by heat wave duration was higher for lower ages, in areas with lower wealth, for hospitalized patients younger than age 65. Odds were elevated among females younger than age 65, in groups with a previous hospital admission for mental disorders, and in persons with previous cardiovascular disease. Gradual increases in summer temperatures were associated with mortality in people older than 80 years, and with mortality in groups with a previous myocardial infarction and with chronic obstructive pulmonary disease (COPD) in the population younger than 65 years. During winter, mortality was associated with a decrease in temperature particularly in men and with the duration of cold spells for the population older than 80. A history of hospitalization for myocardial infarction increased the odds associated with cold temperatures among the population older than 65. Previous mental disease or substance abuse increased the odds of death among the population younger than 65.
  
  
  CONCLUSIONS
  To increase effectiveness, we suggest preventive efforts should not assume susceptible groups are the same for warm and cold days and heat and cold waves, respectively.
authors.affiliation: Department of Public Health and Clinical Medicine, Epidemiology and Global Health, Umeå University, Umeå, Sweden; Joacim.rocklov@envmed.umu.se.
authors.forename: Joacim
authors.initials: J
authors.lastname: Rocklöv
authors.affiliation: Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine, Umeå University, Umeå, Sweden.
authors.forename: Bertil
authors.initials: B
authors.lastname: Forsberg
authors.affiliation: Department of Public Health and Clinical Medicine, Epidemiology and Global Health, Umeå University, Umeå, Sweden; Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine, Umeå University, Umeå, Sweden.
authors.forename: Kristie
authors.initials: K
authors.lastname: Ebi
authors.affiliation: Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Centre for Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden.
authors.forename: Tom
authors.initials: T
authors.lastname: Bellander
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003080:Cold Temperature / Q000009:adverse effects*; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009026:Mortality; D012307:Risk Factors; D012737:Sex Factors; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
keywords: cold; heat; hospitalization; mortality; temperature; weather