Extreme Temperatures Increase Premature Cardiovascular Death

According to the World Health Organization more than 80 percent of deaths due to cardiovascular disease are in low and middle income countries. And premature CVD occurs in developing nations than in richer countries.

A new report that is being handed by the researchers from the Queensland University of Technology (QUT) in Brisbane, Australia, states that, "extreme temperatures during heat waves and cold spells may increase the risk of premature cardiovascular disease death."

This is the first study that examines the association between daily average temperatures and the years of life lost due to CVD.

Years of life lost measures premature death by estimating years of life lost according to average life expectancy.

"The findings are important because of how the body responds to temperate extremes, the growing obesity trend and Earth's climate changes," said Cunrui Huang, M.Med., M.S.P.H., the study's lead researcher and a Ph.D. scholar at the School of Public Health and Institute of Health and Biomedical Innovation at Queensland University of Technology (QUT) in Brisbane, Australia.

The previous studies have stated that exposure to extreme temperature alters blood pressure, blood thickness, cholesterol and heart rate.

"With increasing rates of obesity and related conditions, including diabetes, more people will be vulnerable to extreme temperatures and that could increase the future disease burden of extreme temperatures," Huang said.

The researchers worked on the data on daily temperatures in Brisbane, Australia between 1996 and 2004 and compared them to cardiovascular related deaths in the same period.

"Brisbane has hot, humid summers and mild, dry winters. The average daily mean temperature was 68.9 degrees Fahrenheit, with the coldest 1 percent of days 53 degrees Fahrenheit characterized as cold spells and the hottest 1 percent (84.5 degree Fahrenheit) heat waves. Per 1 million people, 72 years of life were lost per day due to CVD," researchers said.

They found that risk for premature CVD death was high during extreme heat.

"This might be because people become exhausted due to the sustained strain on their cardiovascular systems without relief, or health systems become overstretched and ambulances take longer to reach emergency cases," said Adrian G. Barnett, Ph.D., co-author of the study and associate professor of biostatistics at QUT. "We suspect that people take better protective actions during prolonged cold weather, which might be why we did not find as great a risk of CVD during cold spells."

"Spending a few hours daily in a temperate environment can help reduce heat- and cold-related illnesses and deaths," Barnett said.

The researchers conclude saying this finding may not be applicable to other communities and also they focused more on death rate where CVD was underlying cause.