According to new guidelines released by the American Heart Association, almost all women are at risk of heart disease and doctors should consider prescribing a daily aspirin for them.

In the United States 42.1 million or just over one-third of all women have heart disease and it is the largest single cause of death among women.

The new guidelines add support to recommendations that exercise for at least an hour is important on most days of the week, as is maintaining a healthy weight, eating less fat and more fresh fruit and vegetables and quitting smoking.

Dr. Lori Mosca of the New York-Presbyterian Hospital and colleagues say almost all women are at risk for cardiovascular disease, which underscores the importance of a heart-healthy lifestyle for everyone.

Mosca says since the last guidelines were developed, more definitive clinical trials have become available which suggest that health care providers should consider aspirin in women to prevent stroke.

The new guidelines recommend that women change their eating and exercise habits to control blood pressure and quit smoking.

Exercise is recommended for at least 60 to 90 minutes on most, and preferably all, days of the week, at levels equivalent to brisk walking; saturated fat intake should be lowered to less than 7 percent of calories and oily fish or some other source of omega-3 fatty acids eaten at least twice a week.

The guidelines discourage women from using hormone replacement therapy and selective estrogen receptor modulators such as the osteoporosis drug raloxifene to prevent heart disease.

They also say supplements such as vitamin E, C, folic acid and beta-carotene do not prevent heart disease and should not be taken to prevent it.

However routine low dose aspirin therapy may be considered in women age 65 or older regardless of heart risk and women with a very high risk of heart disease should aim to lower their LDL (low density lipoprotein or "bad" cholesterol) to less than 70 mg/dL.

Meanwhile cardiologists at Johns Hopkins University School of Medicine are calling for an expansion of the criteria widely used by physicians to detect and assess a postmenopausal woman's chances of developing cardiovascular disease.

According to Dr. Roger Blumenthal and colleagues a family history of heart disease and blood levels of a protein tied to vessel inflammation, C-reactive protein, should immediately be added to traditional assessments of women's risk of suffering a heart attack, stroke or severe chest pain (angina).

Blumenthal, an associate professor and director of the Ciccarone Preventive Cardiology Center at The Johns Hopkins University School of Medicine, says doctors should intervene with lifestyle changes and drug treatment before symptoms start to appear.

Blumenthal says the best means of prevention is through early identification of those most at risk.

Such methods he believes could change the discrepancy between the death rate for men and women from cardiovascular disease, which has steadily declined for men over the last 20 years, but has remained relatively the same for women.

The new risk-factor list would strengthen existing assessment tools, including the Framingham Risk Estimate, which gauges how likely a person is to suffer a fatal or nonfatal heart attack within 10 years and calculates risk based on a summary score of such factors as age, blood pressure, cholesterol levels and smoking.

The Hopkins experts say there is clear evidence that only family history and C-reactive protein, or hsCRP for short, had significant, additional predictive value in determining women really at moderate or high risk of future cardiovascular disease.