Vital exhaustion and risk for cancer -: A prospective cohort study on the association between depressive feelings, fatigue, and risk for cancer

BACKGROUND. Vital exhaustion, defined as feelings of depression and fatigue, has previously been investigated mainly as a risk factor for cardiovascular disease. The authors investigated the association between depressive feelings and fatigue as covered by the concept of vital exhaustion and the risk for cancer. METHODS. The sample consisted of 8527 persons aged 21-94 who had been examined in 1991-1994 within the Copenhagen City Heart Study. For the analysis, the sample was divided into quartiles on the basis of vital exhaustion scores. Cancer cases were ascertained by linkage to the Danish Cancer Registry. The mean length of follow-tip was 8.6 years. Regression analyses for etiology-based groups of cancer sites were conducted on the basis of the Cox proportional hazards model, with adjustment for a number of confounding variables. RESULTS. Cancer was diagnosed in 976 persons (12%) during follow-up. In comparison to those with the lowest scores, persons with the highest vital exhaustion scores had a significantly decreased risk for developing cancer at all sites (hazard ratio [HR], 0.80; 95% confidence interval [CI], 0.66-0.96), smoking-related cancers (HR, 0.64; 95% Cl, 0.46-0.90), and virus and immune-related cancers (HR, 0.51; 95% Cl, 0.26-0.99). No significant change in risk was found for cancers related to alcohol consumption or hormones. CONCLUSIONS. The results did not support the hypothesis that symptoms of fatigue and depression, as ascertained in the vital exhaustion index, increased the risk for cancer.