The joint impact of prediagnostic inflammatory markers and cardiorespiratory fitness on the risk of cancer mortality.

Independently, cardiorespiratory fitness (CRF), C-reactive protein (CRP), and leukocyte count have been shown to predict cancer death. Little is known about the joint impact of CRF and prediagnostic markers of inflammation, particularly leukocyte count and CRP, and their prognostic value with cancer death. The aim of this study was to explore the association between prediagnostic inflammatory markers and CRF with cancer mortality. A population-based cohort of 2270 men from Eastern Finland with no cancer history at baseline participated in the study. CRP, leukocyte count, and CRF data were among the measures collected at baseline. Blood leukocyte count was measured with a cell counter, and serum CRP concentrations were measured using an immunometric assay. The highest value or plateau of directly measured oxygen consumption by a respiratory gas analyzer during an incremental exercise test to exhaustion was used to describe CRF. Over an average follow-up of 22 years, 272 cases of cancer mortality occurred. In a multivariate model, the joint impact of high leukocyte count (>5.40 × 109 /L) and low CRF (VO2 max < 30.08 mL kg-1  min-1 ) had a 1.85-fold (95% CI 1.30-2.63, P < .01) increased risk for cancer death compared to men with low leukocyte count (<5.40 × 109 /L) and high CRF (VO2 max > 30.08 mL kg-1  min-1 ). The joint impact of CRP and CRF shared no association with cancer mortality in a multivariate model. The joint impact of high leukocyte count and low CRF increases risk for cancer death, suggesting it is a better predictor of cancer death compared to the joint impact of CRP and CRF.