Ability to Heat or Cool Home Linked to U.S. Coronary Death Decline
For immediate release: September 24, 1997
Boston, MA--In a large, ecological study that assessed 30 million regularly reported coronary deaths and their seasonal variation over 55 years, investigators from the Harvard School of Public Health and Boston University report that the overall decline in coronary deaths in the U.S. closely follows a corresponding expanded use of heating in the winter increased use of air conditioning in the summer, i.e., improvements in microclimatic control. The study is reported in this week's Journal of the American Medical Association.
It has been assumed that personal preventive measures (including better control of hypertension, smoking cessation and dietary modifications) and therapeutic interventions (more effective surgical and medical treatment) have been wholly responsible for the decline in coronary mortality in the U.S. as well as in most other developed nations. To determine whether improvements in heating and air conditioning also play a role in the coronary mortality decline, the investigators studied changes in the seasonal variation of coronary deaths in the United States.
The study noted that the winter-to-summer ratio of coronary death declined from 1937 to 1970 corresponding with improvement in heating conditions across the country. From 1970 on, however, the winter-to-summer ratio started to increase again in tandem with the rapidly expanding use of central air conditioning in homes, at work and in transportation, that selectively reduces summer deaths (and thus increases the winter-to-summer ratio).
"Because the coronary death rate is higher among lower income groups," comments Dimitrios Trichopoulos, MD, professor of epidemiology at the Harvard School of Public Health and coordinator of the study, "and housing and working conditions of the poor are often substandard, our findings lead us to wonder whether this socio-economic differential in deaths can be partly explained in terms of the degree of control of microclimatic conditions."
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