The figure - which is higher than was previously thought - is published in a paper by Dr Debbie Lawlor and colleagues in this month's edition of the Journal of Epidemiology and Community Health.
The research also shows that the high prevalence of risk factors among older women is not matched by levels of preventive treatment.
The findings are based on 4,300 women, randomly selected from 23 towns in England, Wales, and Scotland. The women, aged between 60 and 79, were taking part in the government-funded British Women's Heart and Health Study.
The analyses show that 1 in 5 had been diagnosed with a heart attack, angina, heart failure, stroke or peripheral vascular disease.
The prevalence of risk factors for cardiovascular disease was also high:
- 1 in 2 of all women in the study had high blood pressure
- 12% were smokers
- more than 1 in 4 was obese
- 1 in 2 had a total cholesterol level of 6.5, which is some way above what is considered to be the healthy limit
Among the women with heart disease or stroke:
- 12% were smokers
- one third had high blood pressure for which they were not being treated
- 1 in 3 was obese
- over 90% had a blood cholesterol above 5
Rates of cardiovascular disease were highest in Scotland and lowest in southern England, variations that were not fully explained by prevalence of risk factors, use of health services, or social class.
The authors point out that cardiovascular disease is the leading cause of death among women in industrialised countries and accounts for more than 40% of all deaths among women of all ages in the UK.
The results of this research suggest that heart disease causes a considerable amount of ill health in older British women, who are being poorly managed in terms of their risk factors and secondary prevention.
But they also point out that effectively targeting those women at risk with statins and aspirin has considerable workload implications for doctors. The high prevalence of heart disease (which is often considered a male only condition) among women needs to be recognised, and the importance of not smoking, eating a healthy diet and remaining physically active should be emphasised to women of all ages.