White Blood Cell Counts Hint at Heart Disease Risk
High levels in women indicate greater chances of cardiovascular trouble
MONDAY, March 14, 2005 (HealthDay News) -- A high level of white blood cells indicates an increased risk of heart attack, stroke and other cardiovascular problems in women, a major study finds.
The finding itself is not new, but its application to women is.
"There have been quite a lot of studies that looked at white blood cell count as a predictor of cardiovascular disease," said study author Dr. Karen L. Margolis, an associate professor of medicine at the University of Minnesota. But the research has generally concentrated on men, and "this one is definitely the largest for women," she added.
Her report appears in the March 14 issue of the Archives of Internal Medicine.
The study is part of an increasing focus on cardiovascular disease in women, for whom it is the leading cause of death in the United States. Other studies have found a difference between the sexes -- most notably, one reported last week that showed low-dose aspirin does not reduce the risk of heart attack in women, as it does in men, but does lower the risk of stroke for women.
This latest research uses data from the Women's Health Initiative, which followed more than 72,000 women, aged 50 to 79. Those with a count of more than 6.7 billion white cells per liter of blood -- in the high normal range -- had double the incidence of fatal heart disease. They were also 40 percent more likely to have heart attacks, 46 percent more likely to have strokes and 50 percent more likely to die of all causes over the next six years, as compared to those with a count of 4.7 billion cells per liter.
White blood cells are part of the body's immune defense system, attacking invaders such as bacteria and viruses. White blood cell levels measure inflammation in the body, so the report adds to the growing body of evidence that inflammation play an important role in cardiovascular disease.
Inflammation studies have focused mostly on a molecule called C-reactive protein (CRP) as a marker of inflammation. This study also measured CRP levels and found that white blood cell readings were on the same level as an indicator of risk. Women with elevated levels of both white cells and CRP had a markedly higher risk of cardiovascular -- sevenfold higher than women with lower levels of both markers.
But routine screening of white blood cell levels is not yet in the cards, said Dr. Mary Cushman, an associate professor of medicine at the University of Vermont, who wrote an accompanying editorial in the journal.
"CRP testing now is a very controversial subject," Cushman said. "Adding another test on top of that would increase the controversy. And we don't know what we could do for people with high levels of white blood cells. A lot more work needs to be done."
It's still best to stick to the well-established risk markers, Margolis said. "As a physician, I would ask patients who come into my office first about traditional markers such as age, blood pressure, smoking, diabetes and obesity," she said. "These factors by themselves measure most of the risk."
Cushman said the advice given to someone with elevated markers of inflammation would be the same as for anyone who wants to reduce the risk of cardiovascular disease -- "lose weight, take aspirin and so on." And she worries that a screening program for white blood cell levels might subject people to too many tests.
That might not be so, Margolis said, because "white blood cell counts might be sitting in the charts of a large number of people."
The list of things covered by a routine blood test usually includes white cells, so "if you flip through someone's chart, there's a pretty good chance the white cell count is there. If it is high, maybe the physician should pay attention," she added.
Any questions you might have about white blood cells (the formal name is leukocytes) are answered by the National Library of Medicine.