17th August, 2010
Cold weather has been linked to an increase in the risk of heart attacks, according to a new study by scientists at the London School of Hygiene & Tropical Medicine (LSHTM).
The study, led by Krishnan Bhaskaran, released and published in the British Medical Journal, yesterday, showed that each 1Â°C reduction in temperature on a single day is associated with around 200 extra heart attacks.
Bhaskaran and colleagues said they analysed data of 84,010 patients admitted to hospital with a heart attack between 2003 and 2006 and compared this with daily temperatures in in some western cities. The results were adjusted to take into account factors such as air pollution, influenza activity, seasonality and long term trends.
The researchers found that a 1Â°C reduction in average daily temperature was associated with a cumulative two per cent increase in risk of heart attack for 28 days. The highest risk was within two weeks of exposure.
The heightened risk may seem small but in the United Kingdom alone, there are an estimated 146,000 heart attacks every year, while poor data gathering hinders effective gathering of information relating to this in developing countries like Nigeria. So even a small increase in risk translates to around 200 extra heart attacks for each 1Â°C reduction in temperature on a single day.
The study said that â€œolder people between the ages of 75 and 84 and those with previous coronary heart disease seemed to be more vulnerable to the effects of temperature reductions.â€
Krishnan Bhaskaran also stressed that, â€œwhile people who had been taking aspirin long-term were less vulnerable, we found no increased risk of heart attacks during higher temperatures.
â€œOur results suggest that even in the summer, the risk is increased by temperature reductions.â€
In conclusion, he said, â€œour study shows a convincing short term increase in the risk of myocardial infarction (heart attacks) associated with lower ambient temperature, predominantly in the two weeks after exposure.â€
He added that further studies needed to be conducted to see what measures could be used to prevent the increased risk, such as advising patients, particularly the elderly, to wear suitable clothing and to heat their homes sufficiently.