In a study reported in JAMA Network Open, Paragomi et al found that higher body mass index (BMI) was associated with increased risk of incident colorectal cancer and colorectal cancer–related mortality in Asian countries.
Study Details
The study included data pooled from 17 prospective cohorts (from mainland China, Japan, South Korea, Taiwan, Singapore, and Iran) included in the Asia Cohort Consortium. Cohort enrollment was conducted from January 1984 to December 2002. Analysis of association of BMI (in kg/m2) with risk of incident colorectal cancer included 619,981 participants (mean age = 53.8 years), including 11,900 diagnosed with incident colorectal cancer. Analysis of association of BMI with colorectal cancer–related mortality included 650,195 participants (mean age = 53.5 years), including 4,550 with colorectal cancer–related mortality.
Key Findings
Compared with participants with BMI > 23.0 to 25.0, associations between BMI and risk of incident colorectal cancer (P < .001 for trend) were observed among those with BMI > 25.0 to 27.5 (adjusted hazard ratio [aHR] = 1.09, 95% confidence interval [CI] = 1.03–1.16), BMI > 27.5 to 30.0 (aHR = 1.19, 95% CI = 1.11–1.29), and BMI > 30.0 (aHR = 1.32, 95% CI = 1.19–1.46).
Compared with participants with BMI > 23.0 to 25.0, increased risk of colorectal cancer–related death (P < .001 for trend) was observed among those with BMI > 27.5-30.0 (aHR = 1.18, 95% CI = 1.04–1.34) and BMI > 30.0 (aHR = 1.38, 95% CI = 1.18–1.62). Increased risk (P < .001 for trend) was observed among men with BMI > 30.0 (aHR = 1.87, 95% CI = 1.49–2.34) but not among women (P = .15 for trend; P = .02 for heterogeneity).
BMI-associated risks of colorectal cancer incidence and mortality were greater among participants with colon vs rectal cancer.
Summary
The investigators concluded: “In this cohort study that included a pooled analysis of 17 cohort studies comprising participants across Asia, a positive association between BMI and [colorectal cancer] incidence and related mortality was found. The risk was greater among men and participants with colon cancer. These findings may have implications to better understand the burden of obesity on [colorectal cancer] incidence and related deaths in the Asian population.”
Hung N. Luu, MD, PhD, UPMC Hillman Cancer Center, UPMC Cancer Pavilion, Pittsburgh, is the corresponding author for the JAMA Network Open article.
Disclosure: The study was supported by the National Research Foundation of Korea, Shanghai Men’s Health Study, Japan National Cancer Center Research and Development Fund, and others. For full disclosures of all study authors, visit jamanetwork.com.
