High blood pressure and colorectal cancer mortality in a 29-year follow-up of the Japanese general population: NIPPON DATA80

Onco-hypertension has been proposed, although associations of high blood pressure (BP) with cancer risk remain inconsistent. We examined associations of high BP with risk of mortality from stomach, lung, colorectal, liver, and pancreatic cancers independent of possible confounders in an analysis that excluded deaths within the first 5 years of follow-up to consider the reverse causality. In a prospective cohort representative of the general Japanese population (1980-2009), we studied 8088 participants (mean age, 48.2 years; 56.0% women) without clinical cardiovascular disease or antihypertensive medication at baseline. Fine-Gray competing risks regression was used to estimate hazard ratios for 10 mmHg higher BP adjusted for confounders including smoking, alcohol-drinking, obesity, and diabetes mellitus. During 29-year follow-up, 159 (2.0%), 159 (2.0%), 89 (1.1%), 86 (1.1%), and 68 (0.8%) participants died from stomach, lung, colorectal, liver, and pancreatic cancers, respectively. We observed a positive association of high BP with risk of colorectal cancer mortality but not with mortality risks from any other cancers. The association with colorectal cancer mortality for systolic and diastolic BP was evident in those aged 30-49 years (hazard ratios 1.43 [95% confidence interval, 1.22-1.67] and 1.86 [1.32-2.62], respectively) but not in those aged 50-59 years and ≥60 years (P for age interaction <0.01 for systolic and diastolic BP). The associations with colorectal cancer mortality were similar in the analyses stratified by smoking, alcohol-drinking, obesity, and diabetic status. In conclusion, high BP among young to middle-aged adults was independently associated with risk of colorectal cancer mortality later in life.