New Risk Factors Linked to Heart Disease

If you're a postmenopausal woman, you may be more likely to develop cardiovascular disease than you think. It used to be that age, blood pressure, cholesterol levels and smoking were the major risk factors that were used by most doctors to assess the risk of heart disease for older women. But new research, reported in the Journal of the American Medical Association (JAMA) February 14, 2007, shows that there are two more very important risk factors that should be considered.

As a result, Johns Hopkins cardiologists are calling for an expansion of the criteria to assess a postmenopausal woman's chances of developing cardiovascular disease. Those two new risk factors are family history and blood levels of a protein tied to blood vessel inflammation.

According to the new research, if a woman's parent or a sibling has suffered a coronary event, her own chances of arterial disease are doubled. Her risk is also doubled if she has high blood levels of C-reactive protein, in excess of 3 milligrams per liter. If both new risk factors are present, a woman's probability of having a heart attack or stroke jumps nearly fourfold. By adding the two new risk factors, the risk scores changed for at least 20% of the women studied.

This comes as no surprise to Dr. Roger Blumenthal, who is the director of the Ciccarone Preventive Cardiology Center at The Johns Hopkins University School of Medicine. Blumenthal conducted research in 2005 using the old Framingham Risk Estimate that has two fewer risk factors than the new one called the Reynolds Risk Score. The old risk model failed to identify about 30% of women over age 60 that had advanced hardening and narrowing of the arteries.

Doctor Blumenthal says, "Our best means of prevention is through early identification of those most at risk." Blumenthal adds that "...physicians should intervene with lifestyle changes and drug treatment before symptoms start to appear." Blumenthal suggests that additional screening, using CT scans of the arteries and calcium scoring, is a good idea to better find women who would likely benefit from aspirin and statin therapy to prevent heart attacks and strokes. Blumenthal also believes those additional screening tests should be considered for women with no symptoms and at least two traditional risk factors who are also undergoing lifelong drug therapy with aspirin and lipid-lowering drugs.

Cardiologist Erin Michos, a clinical fellow at Hopkins, strongly agrees with Blumenthal. Michos says the new Reynolds Risk Score guidelines should make heart attacks and strokes less likely to occur. However, that will depend on therapies such as aspirin and cholesterol-lowering medications being prescribed for individuals at higher risk.

The old Framingham Risk Estimate was developed over the decade spanning 1956 to 1966. Researchers in Framingham, Massachusetts, defined age, high blood pressure (hypertension), smoking, diabetes and high cholesterol (hyperlipidemia) as the major determinants of coronary heart disease and coined the term "coronary risk factors." Up until now, the model for predicting cardiovascular disease for women has remained largely unchanged for the past 40-plus years.

The new Reynolds Risk Score was developed by Paul M Ridker, M.D., M.P.H. and his colleagues from Brigham and Women's Hospital in Boston.

Ridker's research assessed 35 risk factors among a pool of nearly 25-thousand initially healthy women, 45 years or older, who were free of cardiovascular disease and cancer. The participants in the study were followed up for a median of 10.2 years for cardiovascular events, such as heart attack (myocardial infarction), stroke, heart surgery, and cardiovascular related deaths.

The researchers on Ridker's team used data from randomly selected two-thirds of the women in the study to develop new algorithms that were then used to compare outcomes in the remaining one-third of women. The result was the new Reynolds Risk Score, which adds the factors of family history and C-reactive protein (CRP) onto the original list of age, blood pressure, cholesterol levels and smoking. The other 33 risk factors that were assessed were not found to be significant in predicting cardiovascular disease in postmenopausal woman.

Coronary heart disease (CHD) is the leading cause of death for women and men in the United States. Half of all people who suffer a first major coronary event have no prior symptoms.