The association between circulating white blood cell count, triglyceride level and cardiovascular and all-cause mortality: Population-based cohort study

Objectives To examine the individual and combined relationship between elevated white blood cell count (WBC), triglyceride level and cardiovascular and all-cause mortality among older Australians. Design Prospective population-based cohort study. Setting Community in Blue Mountains region, Australia. Participants 2904 individuals, aged 49–84 years, free of cardiovascular disease and cancer at the baseline examination. Main outcome measures Cardiovascular (n = 242) and all-cause mortality (n = 575). Results Elevated WBC count and triglyceride level were found to be associated with cardiovascular and all-cause mortality, independent of several important confounders. Multivariable relative risk [RR] (95% confidence interval [CI]) comparing fourth (6.8 × 109 cells/L and above) versus first quartile (4.8 × 109 cells/L and below) of WBC count was 2.01 (1.40–2.90) for cardiovascular mortality and 1.68 (1.35–2.09) for all-cause mortality. Multivariable RR (95% CI) comparing fourth (1.98 mmol/L and above) versus first quartile (0.95 mmol/L and below) of triglyceride level was 1.58 (1.08–2.30) for cardiovascular mortality and 1.40 (1.11–1.77) for all-cause mortality. Furthermore, a combined exposure to the fourth quartiles of both WBC count and triglyceride level was found to be related to more than three-fold risk of cardiovascular mortality (RR [95% CI]: 3.15 [2.17–4.57], p-interaction = 0.01), independent of traditional risk factors. Conclusions Elevated WBC count and triglyceride level were associated with cardiovascular and all-cause mortality among older Australians. These data provide new epidemiological evidence regarding cardiovascular risk stratification using simple, inexpensive, and routinely available measures, suggesting that a combined exposure to both high WBC count and triglyceride level is related to more than three-fold risk of cardiovascular mortality, independent of traditional risk factors.