This is not a *CR* study but it does offer some more evidence suggesting that having a low white blood count is optimal. We see a dramatic drop in wbc usually when a person or animal is calorie restricted. The reference range as it stands now is probably too wide, and anything above what is considered low-normal is a risk factor. So one should aim for a total wbc of around 3.0 - 5.0 in my opinion.
Prospective Study of Leukocyte Count as a Predictor of Incident Breast, Colorectal, Endometrial, and Lung Cancer and Mortality in Postmenopausal Women
Karen L. Margolis, MD, MPH; Rebecca J. Rodabough, MS; Cynthia A. Thomson, PhD, RD; Ana Maria Lopez, MD; Anne McTiernan, MD, PhD; for the Women's Health Initiative Research Group
Arch Intern Med. 2007;167:1837-1844.
Background The immune system and inflammation are implicated in the pathogenesis of cancer. Prospective studies linking biomarkers of inflammation with cancer incidence and mortality have been inconclusive.
Methods To determine whether there is an independent association of white blood cell (WBC) count with incident cancer in postmenopausal women, a prospective cohort study was performed at 40 US clinical centers involving 143 748 postmenopausal women aged 50 to 79 years who were free of cancer at baseline and were enrolled in the Women's Health Initiative. The main outcome measures were incident invasive breast, colorectal, endometrial, and lung cancer.
Results In multivariate models, there was a graded association of WBC count with incidence of all 4 types of cancer. Compared with the lowest quartile of WBC count (2.50-4.79x109 cells/L), women with a WBC count in the upper quartile (6.80-15.00x109 cells/L) had a statistically significantly higher risk of invasive breast cancer (hazard ratio
, 1.15; 95% confidence interval [CI], 1.04-1.26), colorectal cancer (HR, 1.19; 95% CI, 1.00-1.41), endometrial cancer (HR, 1.42; 95% CI, 1.12-1.79), and lung cancer (HR, 1.63; 95% CI, 1.35-1.97). The findings were similar when cancers that occurred during the first 2 years of follow-up were excluded. Statistically significant associations remained for invasive breast cancer and endometrial cancer when the analyses were limited to nonsmokers. The WBC count was also statistically significantly associated with breast cancer, lung cancer, and overall cancer mortality.
Conclusion Postmenopausal women with higher WBC counts have a higher risk of incident invasive breast, colorectal, endometrial, and lung cancer, as well as a higher risk of breast, lung, and overall cancer mortality.