A systematic review on health effects following long-term exposure to temperature

Abstract

Background/Aim Health effects of long-term exposure to temperature have only recently received attention. We performed a systematic review to assess health associations with long-term (exceeding three months) exposure to temperature metrics in the framework of the EXHAUSTION project.Methods We performed a systematic search in PubMed and Web of Science databases up to October 2019. The search resulted in 61 studies meeting inclusion criteria from the 2946 records screened.We identified 14 studies including total mortality, 16 including cardiovascular outcomes, 11 including respiratory outcomes, 16 with birth outcomes and 15 on outcomes other than those above.Results Studies investigating annual mortality changes in relation to annual temperature metrics show that extreme and variable temperature is associated with adverse health outcomes at an annual level, indicating that aggregate effects of temperature extremes cannot be attributed to short-term mortality displacement. Studies on cardiovascular mortality show stronger associations with low rather than high temperature, whilst those on blood pressure report that in populations living in warmer climates levels tend to be lower. Studies on respiratory outcomes generally report effects of both heat and cold, but they are limited in number and use diverse health endpoints. Several studies report on birth outcomes as well as other outcomes with less consistent results. Air pollution interaction effects have not been assessed in any study. Other potential effect modifiers that were investigated in a limited number of studies, indicate stronger effects among the elderly and socially deprived.Conclusions Our review revealed gaps in previous research related to the study of long-term effects of temperature. More and better designed studies are needed. The investigation of effect modification by air pollutants and other environmental factors will add valuable information for policy decisions on climate change adaptation and mitigation.