The Durk Pearson & Sandy Shaw®
Life Extension NewsTM
Volume 13 No. 4 • August 2010


White Blood Cell Count and Risk of Mortality

Three papers1,2,3 focus on the very interesting relationship between increased white blood cell numbers and the morbidity and mortality of acute and chronic vascular disease.

One of these papers1 reports that in the oldest old (age 85 and older), white blood cell (WBC) count and CRP (C-reactive protein, a strong marker of systemic inflammation and a good predictor of vascular events and mortality1), were both independently predictive of mortality. A total of 599 85-year old women and men were followed for five years in the Leiden-85-plus Study. Blood samples were taken at age 85 and then yearly; after age 90, remaining subjects were followed up for mortality. The results showed that for every increase of 1 SD (standard deviation) in WBC count, there was a 1.26 (95% confidence interval [CI]=1.15-1.38) increased risk for all-cause mortality, with similar increased mortality risks for both vascular mortality and nonvascular mortality. An increase of 1 SD in CRP level was associated with a 1.22 (95% CI=1.10-1.35) increased risk for all-cause mortality, with similar increases in mortality risk for nonvascular mortality. There was a tendency for an increased risk of vascular mortality (that is, it didn’t quite reach statistical significance).

A second paper2 reviews the association between leukocytosis (increased white blood cell numbers) and increased morbidity and mortality of ischemic vascular disease. The author refers to the discussion in Dr. Paul Dudley White’s 1949 edition of his text on heart disease, in which Dr. White wrote (without a reference) that severe and sustained leukocytosis after myocardial infarction was associated with poor prognosis. In 1954, it was reported by Cole et al4 that more than 32% of patients with an acute heart attack having a white blood cell count of greater than 15,000/uL died within the first two months after the attack, whereas less than 9% of patients with a WBC count less than 10,000/uL died within the first two months. Studies involving over 350,000 patients treated with “more modern therapies” have been published to date and “in nearly all of these studies, a significant relationship between leukocyte count and vascular disease morbidity and mortality was observed.”2 The paper2 summarized the results of selected studies assessing the association between WBC count and morbidity and mortality of ischemic vascular diseases from 1999–2004. The author2 states that “regardless of the mechanism underlying the association between leukocytosis and mortality after acute myocardial infarction, it appears that modern reperfusion and early revascularization strategies mitigate or eliminate the association between WBC count and mortality during the first 6 months after a myocardial infarction.”

The third paper3 reports that in cholesterol-fed rabbits (either a 0.25% or a 0.1% cholesterol-enriched diet), circulating WBC were elevated by one week of feeding and these higher levels were sustained for at least 30 weeks. But switching the cholesterol-fed rabbits to a regular rabbit chow diet resulted in a reversal to pre-treatment levels of WBC.

Aspirin May Lower WBC Counts

Paper #2 reports that in four separate studies of leukocytosis and cardiovascular risk involving a total of greater than 160,000 patients, “aspirin use was associated with significantly lower WBC counts.” However, the author cautions “[b]ecause these studies were not randomized, many confounding factors may have influenced the apparent association between aspirin use and lower leukocyte counts.”2 Here, again, is a relatively simple and potentially important hypothesis to test in a randomized trial: whether aspirin can be used to reduce excessive WBC counts.

References

  1. Willems et al. White blood cell count and C-Reactive protein are independent predictors of mortality in the oldest old. J Gerontol A Biol Sci Med Sci 65(7):764-8 (2010).
  2. Coller. Leukocytosis and ischemic vascular disease morbidity and mortality: is it time to intervene? Arterioscler Thromb Vasc Biol 25:658-670 (2005)
  3. Feldman et al. Leukocytosis in rabbits with diet-induced atherosclerosis. Arterioscler Thromb Vasc Biol 11:985-94 (1991).
  4. Cole et al. The long-term prognosis following myocardial infarction, and some factors which affect it. Circulation 9:321-34 (1954).

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