Perceived psychologic stress and colorectal cancer mortality: Findings from the Japan collaborative cohort study

Objective: The purpose of this research was to examine the relationship between perceived psychologic stress and colorectal cancer mortality in a prospective large-scale study. Methods: Between the years 1988 and 1990, 32,153 men and 45,854 women aged 40 to 79 years were enrolled. Participants completed a self-administered questionnaire that addressed demographic, lifestyle, and psychosocial characteristics. Subjects were subsequently followed for mortality until the end of 1999. Perceived psychologic stress was assessed using the question "Do you feel stress during your daily life?" The 4 possible responses, ranging from "little or none" (1) to "extreme" (4), were dichotomized as low (1 or 2) or high (3 or 4) stress. Relative risks (RRs) with 95% confidence intervals (CIs) for colon and rectal cancer according to the perceived level of stress were estimated using Cox's proportional hazard model. Results: During the follow-up period (average, 9.6 years), 193 colon cancer deaths (96 men and 97 women) and 127 rectal cancer deaths (88 men and 39 women) were confirmed within the study group. Women who reported high stress had a 1.64-fold higher risk of colon cancer mortality (multivariate-adjusted RR, 1.64; 95% CI, 1.01-2.66) compared with those reporting low stress. There was no significant association between perceived stress and female rectal cancer or male colon and rectal cancer mortality. Conclusions: Perceived psychologic stress was weakly associated with increased mortality from colon cancer in women. No positive or inverse association was found in men. Further studies are needed to confirm our results.