Toronto, Sep 27 (IANS) Seniors with heart failure should avoid fog and low cloud in the winter as changes in temperature and atmospheric pressure could increase risk of heart failure and death among the elderly, suggests new research. A drop of 10 degrees Celsius in the average temperature over seven days, which is common in several countries because of seasonal variations, is associated with an increased risk in being hospitalised or dying of heart failure of about seven per cent in people aged over 65 diagnosed with the disease, according to the study published in the journal Environment International. "Our study shows that exposure to cold or high-pressure weather could trigger events leading to hospitalisation or death in heart failure patients," said Pierre Gosselin, lead author of the study from Universitie Laval in Canada. In the new study, the team assessed 112,793 people aged 65 years and older who had been diagnosed with heart failure in Canada between 2001 and 2011. The participants were followed for an average of 635 days. During this time, the researchers measured the mean temperature, relative humidity, atmospheric pressure and air pollutants in the surrounding environment and studied the data to see if there was an association. The results showed a higher risk of hospitalisation or death in the winter period of the year (October to April) compared to the summer period (May to September). The researchers noticed that the risk of experiencing hospitalisation or death due to heart failure increased 0.7 percent for every one degree Celsius decrease in the mean temperature of the previous seven days. They also found that the risk of heart failure incident increased by 4.5 per cent for each increase of one kPa (kilopascal) in atmospheric pressure. Heart failure patients should "avoid exposure to fog and low cloud weather in winter as they often accompany high pressure systems", Gosselin said.