Humidity Boosts Heart Attack Risk in Elderly

High humidity, even in a relatively mild climate, heightens the risk of a heart attack among the elderly, according to a new study.

Researchers from Hippokration Hospital (Athens, Greece) analyzed all reported deaths in Athens for the year 2001 and looked at daily weather reports from the Greek national meteorologic society on temperature, pressure levels, and humidity for the same year. The total number of acute myocardial infarction (AMI) deaths during the year numbered 3,126, of which 1,953 were men.

There were sharp seasonal variations in the timing of the deaths, with the overall proportion of deaths a third higher in winter than in summer. Deaths among those aged 70 and above accounted almost entirely for this variation; in this age group deaths from heart attack were 3.5 times higher in June and seven times higher in December than rates in other age groups. The average daily temperature for the preceding week was the most significant factor influencing the daily death rate, but average monthly humidity was the single most important factor influencing average monthly death rates from heart attack in those over 70. The study was published in the July 2006 issue of the journal Heart.

"Ambient temperature is an important predictor of AMI mortality even in the mild climate of a Mediterranean city like Athens, its effects being predominantly evident in the elderly,” said lead author Dr. Polychronis E. Dilaveris.

The December peak of deaths has often been attributed to the Merry Christmas coronary phenomenon, a combination of overindulgence in food and alcohol, combined with emotional stress, said the authors. However in Greece, Easter is celebrated with even more passion than Christmas, yet there is no equivalent peak in heart attack deaths at Easter.