Australians more likely to have a stroke in winter
31 January 2003
Australians are more likely to have a stroke in winter, with fatality rates highest in winter and spring, an international conference will be told next month.
(Stroke occurs when oxygen supply is cut off to an area of the brain, usually because a blood clot has lodged or formed in the brain. Less commonly strokes can be caused by a burst blood vessel in the brain or on its surface; local bleeding then damages nerve cells in that area of the brain.)
John Hunter Hospital and University of Newcastle researchers found that stroke rates were highest in winter and lowest in summer, with a marked increase in those aged 65 and older.
People were most likely to die within 28 days of the stroke in spring and within 12 months of the stroke in winter.
'The biological reasons are not quite clear but we think blood pressure in winter may generally be higher in elderly people, blood viscosity ('stickiness' or thickness) is probably higher and more people suffer from respiratory infections which are risk factors for stroke,' said Dr Yang Wang, National Health & Medical Research Council (NHMRC) research fellow in neurology at John Hunter Hospital.
Total cholesterol and triglycerides also tended to be higher in colder months.
Results of the study, which have been accepted for publication this year in the journal Stroke, will be presented at the 28th International Stroke Conference in Arizona from 13-15 February 2003.
Researchers analysed data from the years 1995 to 2000 on 3803 people with stroke from the Hunter Region's hospital-based heart and stroke register.
Stroke incidence in winter was 57 per 100,000 of population, compared with 48 per 100,000 in summer.
Dr Wang said findings from this and a similar Melbourne study over 20 years ago strongly suggested a seasonal variation in stroke in Australia or the southern hemisphere.
(Risk factors for stroke include high blood pressure; atrial fibrillation (a heart condition in which the atrium of the heart beats rapidly and irregularly); smoking; diabetes; high cholesterol; older age; a family or personal history of stroke; poor diet; excessive alcohol intake; obesity; lack of exercise; and taking birth control pills.)
Last Reviewed: 30 January 2003
- 1. Medical Observer Weekly 31/03/01
