Heart disease risk in older women identified by simple blood test

Mar 15 2005

Postmenopausal women who are not identified by traditional cardiovascular risk factors, could benefit from a simple blood test to show their white blood cell (WBC) count which may predict cardiovascular events and risk of death.

In the development of atherosclerosis, thickening and hardening of the arteries, there is increasing evidence that inflammation is a factor.

The number of different molecules involved in inflammation has been used as a way to identify and monitor patients at risk for coronary heart disease; white blood cell count is a stable, well-standardized, widely available and inexpensive measure of systemic inflammation.

Karen L Margolis, M.D., M.P.H., of the Hennepin County Medical Center, Minneapolis, and colleagues used data of 72,242 postmenopausal women aged 50 to 79 years from the Women’s Health Initiative (WHI) Observational Study to assess white blood cell count as an independent predictor of cardiovascular events (for example, heart attack or stroke) and death from any cause.

The women were comprehensively screened for personal information, medical history, previous history of cardiovascular events or cancer, and blood collection at the beginning of the study. Follow-up was by annual questionnaires, and in the third year participants attended a clinic.

The size and breadth of the study provides an ideal opportunity to determine if the association of white blood cell count with future cardiovascular events is evident in postmenopausal women and to check the independence of this connection from other known CVD risk factors and biomarkers. Other risk factors and biomarkers included in the analysis were age, race, ethnicity, baseline hypertension, diabetes, smoking, body mass index diet, physical activity, current use of aspirin or hormone therapy and C-reactive protein, a biomarker for inflammation.

White blood cell counts were measured at the beginning of the study and women were divided into four levels, with the first representing women with the lowest level of white blood cells and the fourth women with the highest level. Medical histories were taken each year for six years of follow-up. Only women who were entirely free of clinical CVD and cancer at the beginning of the study were included in the analysis.

Women in the fourth level had a doubled risk for coronary heart disease death compared with women in the first level. Women in the top level also had a 40 percent higher risk of heart attack, a 46 percent higher risk of strokes, and 50 percent higher risk for total mortality.

Cardiovascular risk identification by inflammatory markers, including the WBC count, may identify high-risk individuals who are not currently identified by traditional risk factors; further studies are needed to assess the effectiveness of risk reduction in these patients.