Warmer Temperatures Raise Death Rates

Previously, researchers show that heat waves are associated with increased death in the short term. In that that the impact of long-term changes in climate temperature have been unclear, Antonella Zanobetti, from Harvard School of Public Health (Massachusetts USA), and colleagues designed a study that examined climate change is by year within 135 individual cities, involving 3.7 million study subjects who had a chronic medical condition, such as COPD, congestive heart failure, diabetes, or myocardial infarction. In their model that adjusted for ozone, the increase in mortality for each one-degree Celsius increase in summer temperature was 3.7% for those with COPD, and 2.8% for those with congestive heart failure. Pooling the data according to region of the country, the team found greater increases in mortality in the hottest areas. Among patients with myocardial infarction, the hazard ratio per one-degree Celsius temperature deviation rose significantly, when comparing the coolest areas of the country versus the hottest areas. Further, the amount of green space in a given geographic area was an additional factor. Living near or in an area with higher percentage of land with a green surface associated with higher survival rates, as compared to living in an urban area. The study authors conclude that: “Our data suggest that long-term increases in temperature variability may increase the risk of mortality in different subgroups of susceptible older populations.”