Adult Height and Risk of Colorectal Cancer: A Pooled Analysis of 10 Population-based Cohort Studies in Japan

Background: While tall stature has been linked to an increase in the risk of colorectal cancer (CRC), its association with cancer in the colorectum and its subsites remains unclear among Asians. Methods: We conducted a pooled analysis of 10 population-based cohort studies among adults in Japan. Each study estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC incidence associated with adult height were estimated using Cox proportional hazards regression with adjustment of the same set of covariates were then pooled to estimate summary HRs incidence using random-effect models. Results: We identified 9,470 CRC incidences among 390,063 participants during 5,672,930 person-years of follow-up. Men and women with tall stature had a higher risk of CRC and colon cancer. HRs for CRC, colon cancer, and distal colon cancer for the highest versus lowest height categories were 1.23 (95% CI, 1.07–1.40), 1.22 (95% CI, 1.09–1.36), and 1.27 (95% CI, 1.08–1.49), respectively, in men and 1.21 (95% CI, 1.09–1.35), 1.23 (95% CI, 1.08–1.40), and 1.35 (95% CI, 1.003–1.81), respectively, in women. The association with proximal colon cancer and rectal cancer was less evident in both sexes. Conclusion: This pooled analysis confirms the link between tall stature and a higher risk of CRC and colon cancer (especially distal colon) among the Japanese and adds evidence to support the use of adult height to identify those at a higher risk of CRC.