Heat wave impact on morbidity and mortality in the elderly population: a review of recent studies

Background: The on-going climate change is predicted to yield a growing number of extreme climate events which will increase in both intensity and frequency. Increased longevity is changing society's demographics. It is very likely this will have a direct impact on population health. Many studies have previously shown that the elderly in a society are among the most vulnerable to heat waves.

Objectives: With a rapidly growing number of publications on this subject the objective was to review the recent literature for research regarding the impact of heat waves and elevated temperature on the elderly with regards to mortality and morbidity.

Methods: PubMed was searched to identify studies published in English between 1st of January 2008 and 31st of December 2010 using the following key words: heat wave, mortality, morbidity, elderly and temperature. The relationship between high temperature and mortality and/or morbidity had to be studied. Results for the elderly had to be provided.

Results: Six studies of temperature-morbidity-relationship were found and 24 studies of temperature-mortality-relationship. Studies consistently reported increases in cardiovascular and respiratory mortality, as appeared also respiratory admissions to do during hot days and heat waves. However, the number of studies on morbidity published was much fewer. Few studies reported social, medical and environmental susceptibility factors.

Conclusions: Future research should focus on studying susceptibilities and to non-fatal events which are not as studied as mortality. Studies on the modification of type of urban environment, housing and mortality and morbidity in the elderly population are also needed.