HARVARD GAZETTE ARCHIVES

Heating, AC Reduce Deaths from Heart Attacks

By William J. Cromie

Gazette Staff

Heating and air conditioning contributed to a drop in fatal heart attacks during the past 55 years, researchers at the School of Public Health claim.

They checked records of monthly heart deaths from 1937 through 1991 in the United States. Improved heating seems to account for part of the drop in deaths until 1970. After that, air conditioning apparently was more important.

"It has long been recognized that cold temperatures act as a trigger for coronary events," the researchers wrote in yesterday's Journal of the American Medical Association. "The decline in seasonality of coronary mortality until 1970 is compatible with an effect of heating in countering the effects of cold. Migration from rural areas to cities may have contributed to this decline by reducing the population that is simultaneously exposed to physical exertion and extreme cold."

After 1970, air conditioning played a role in blunting the effects of heat waves on heart attacks. Central air was rare before 1970, and room air conditioners cooled only about 41 percent of all housing units. By 1991, almost 70 percent of houses and apartments were cooled by central or room air conditioning.

At the same time, new medical treatments and lifestyle changes contributed significantly to the drop in heart disease and deaths. Some experts believe that changes in diet, lowering blood pressure, exercising more, and quitting smoking account for as much as half of the reduction in heart-attack deaths in the United States and other developed countries. Heart drugs, surgery, and other medical treatments get credit for the other half.

"But little attention has been directed to the possibility that improvements in heating and cooling at home, in the workplace, or during transportation have contributed to the marked decline of coronary mortality in developed countries," notes Dimitrios Seretakis, lead author of the report.

Despite the welcome decline, heart attack remains the single greatest killer of Americans. Hardly a minute goes by that someone in this country does not die from one, according to the American Heart Association.

"Socioeconomic factors still contribute to this toll," declares Dimitrios Trichopoulos, director of the study and Gregory Professor of Cancer Prevention. "Heart-attack deaths are more common among low-income people. Housing and working conditions of the underprivileged are often substandard. Public officials must take that into consideration when they make decisions about the costs of subsidizing heating and cooling for some groups. There are no statistics on this as far as I know, but I would guess that giving people more control of temperatures where they live and work might prevent thousands of deaths from heart attacks each year."

Other researchers who contributed to this study include Pagona Lagiou, Loren Lipworth, and Lisa Signorello of the School of Public Health, and Kenneth Rothman of Boston University Medical Center.