Stanford University researchers were testing the hypothesis that socio-economic status (SES), measured principally by the education level attained, would be the key factor in determining which women developed disease of the cardiovascular system, including the heart.

They found that status did have an effect, but it did not explain the significant differences between white women and both black and Mexican-American women in determining CVD risk.

Risk variation

The study looked at 5,266 women.

It suggests that ethnic variations in CVD risk - as measured by blood pressure, body mass index, physical inactivity, cholesterol levels, and diabetes rates - may be genetically based.

The authors say there are large differences in CVD risk factors by SES, a finding they believe illustrates the high-risk status of both ethnic minority women as well as white women with low SES.

Global problem

The authors explain: "Our findings are especially relevant in light of the global rise of CVD and other chronic diseases that are influenced by increasing prevalences of hypertension, cigarette smoking, hypercholesterolemia, obesity, physical inactivity and diabetes.

"The striking differences by both ethnicity and SES underscore the critical need to improve screening, early detection, and treatment of CVD-related conditions for black and Mexican American women, as well as for women of lower SES in all ethnic groups," they say.

Heart disease accounts for 500,000 deaths among US women annually.