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 x 10(9) cells/L and above) versus first quartile (4.8 x 10(9) 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.