Wellington, June 26 : Researchers from the University of Queensland have confirmed an association between winter months and an increase in heart failure.
Working with a team of researchers from the Departments of Clinical Pharmacology and Cardiology at the Royal Adelaide Hospital, Sally Inglis, a PhD student at the University of Queensland, examined the seasonal differences in hospital admissions and deaths in 2961 patients with chronic heart failure residing in South Australia over the period July 1994 to June 2004.
"After examining the results it was clear that heart failure-related hospitalisations peaked in winter and were lowest in summer," the NZPA quoted her, as saying.
"Similarly, deaths in those diagnosed with heart failure were higher in winter and lowest in summer."
People aged over 75 were most at risk from seasonal variations, she added.
The hottest months of the year, January and February, had the lowest hospitalisation and death rates, even though temperatures in Adelaide peaked well above 30 degrees for days at a time.
Several studies have shown dramatic seasonal differences increase heart failure rates in the northern hemisphere, but this research, is the first to show the same is true of milder winters in the southern hemisphere.
"It was interesting how similar our findings were to those from other climates," Inglis said.
"The climates in which this phenomenon has been previously studied are quite different to that of Adelaide.
"We were surprised that these patients from Adelaide seemed to be able to tolerate the hot summer temperatures in Adelaide without an increase in hospitalisations or deaths, which has been reported in some northern hemisphere studies during heat waves," she added.
Inglis said the findings are further proof of the extra pressure on hospitals in winter, and they also indicate that people at risk of heart problems need careful attention in the lead-up to the cold season.
"Patients and their health care providers need to be aware of this and take adequate preventative measures to reduce the risk," she said.
The study is published in the European Journal of Heart Failure.