White blood cell count in elderly is clinically useful in predicting long-term survival

Introduction. White blood cell (WBC) count is often included in routine clinical checkups. We determined the prognostic impact of WBC count on all-cause, cardiovascular, and noncardiovascular mortality during an 11-year followup in a general population of 75-year-olds. Study Population. The study included 207 men and 220 women comprising 69% of the invited 75-year-olds in a defined geographical area. Main Results. The median WBC count (in 10(9)/L) was 6.3 (interquartile range 5.4-7.2) for men and 5.7 (4.9-6.8) for women, P < 0.001 for sex difference. The hazard ratio (HR) for all-cause mortality per 10(9)/L increase in WBCs was 1.16 (95% confidence interval, 1.03-1.32; P = 0.016) in men and 1.28 (1.10-1.50; P = 0.002) in women. These HRs were essentially unchanged by adjustment for established risk factors (current smoking, known hypertension, prior myocardial infarction, known diabetes, total cholesterol, high-density lipoprotein cholesterol, and body mass index). Furthermore, increased WBC count was significantly associated with cardiovascular mortality in both sexes and with noncardiovascular mortality in women. Conclusions. The WBC count deserves attention as a potentially clinical useful predictor of survival in the 75-year-olds, especially among women.