The majority (84%) of people with AF are over the age of 65 years. In the UK, the prevalence of AF is 7.2% for patients aged 65 and over. AF is a particularly important risk factor for stroke in the elderly. 15% of all strokes are associated with the arrhythmia, increasing to 36% in people over the age of 80. The prevalence of AF is higher in men at all ages, although the overall number of patients with AF is approximately equal between the sexes because of unequal death rates. In overall terms, approximately 50% of patients with AF are 75 or over, and over half of these are women.