Abdominal obesity and colorectal cancer risk: a systematic review and updated meta-analysis
4 affiliations
- 1Student Research Committee, Iran University of Medical Sciences
- 2Department of Epidemiology, School of Public Health, Tehran University of Medical Sciences
- 3Health Promotion Research Center, Zahedan University of Medical Sciences
- 4Preventive Medicine and Public Health Research Center, School of Medicine, Iran University of Medical Sciences
Abstract
Background This meta-analysis investigates the association between abdominal obesity, as measured by waist circumference (WC) and waist-to-hip ratio (WHR), and the risk of colorectal cancer (CRC). Methods We systematically searched PubMed, Scopus, and Google Scholar for relevant English-language prospective cohort studies. Nine studies met the inclusion criteria for the primary meta-analysis, comprising 13,193,908 participants with 131,438 incident CRC cases. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were estimated using a random-effects model. Results Central obesity was associated with a 31% increased risk of CRC (RR = 1.31; 95% CI: 1.25–1.37). The risk was higher in men (RR = 1.41; 95% CI: 1.31–1.52) than in women (RR = 1.26; 95% CI: 1.19–1.34; P for subgroup difference = 0.04). The association was stronger for colon cancer (RR = 1.37; 95% CI: 1.27–1.47) than for rectal cancer (RR = 1.18; 95% CI: 1.11–1.26; P < 0.001). Waist circumference specifically showed a 32% increased risk (RR = 1.32; 95% CI: 1.25–1.41). Studies using measured WC/WHR reported a higher risk (RR = 1.48; 95% CI: 1.36–1.61) than those using self-reported measures (RR = 1.26; 95% CI: 1.20–1.32; P < 0.001). No significant heterogeneity was found by exposure type (WC vs. WHR) or geographic region. Conclusions Central obesity is a significant and independent risk factor for colorectal cancer, with stronger associations observed for colon cancer than for rectal cancer and higher relative risks in men than in women. Visceral fat appears to play a critical role in colorectal carcinogenesis. Maintaining a healthy waist circumference through regular physical activity and a balanced diet remains a key strategy to reduce CRC risk.
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BibTeX
@article{faghirganji2026abdominal,
title = {{Abdominal obesity and colorectal cancer risk: a systematic review and updated meta-analysis}},
author = {Monireh Faghir-Ganji and Narjes Abdolmohamadi and Alireza Ansari-Moghaddam and Babak Eshrati},
journal = {BMC Cancer},
year = {2026},
month = jul,
doi = {10.1186/s12885-026-16351-1},
url = {https://doi.org/10.1186/s12885-026-16351-1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Abdominal obesity and colorectal cancer risk: a systematic review and updated meta-analysis
AU - Monireh Faghir-Ganji
AU - Narjes Abdolmohamadi
AU - Alireza Ansari-Moghaddam
AU - Babak Eshrati
PY - 2026
DA - 2026/07/01
JO - BMC Cancer
DO - 10.1186/s12885-026-16351-1
UR - https://doi.org/10.1186/s12885-026-16351-1
AB - Background This meta-analysis investigates the association between abdominal obesity, as measured by waist circumference (WC) and waist-to-hip ratio (WHR), and the risk of colorectal cancer (CRC). Methods We systematically searched PubMed, Scopus, and Google Scholar for relevant English-language prospective cohort studies. Nine studies met the inclusion criteria for the primary meta-analysis, comprising 13,193,908 participants with 131,438 incident CRC cases. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were estimated using a random-effects model. Results Central obesity was associated with a 31% increased risk of CRC (RR = 1.31; 95% CI: 1.25–1.37). The risk was higher in men (RR = 1.41; 95% CI: 1.31–1.52) than in women (RR = 1.26; 95% CI: 1.19–1.34; P for subgroup difference = 0.04). The association was stronger for colon cancer (RR = 1.37; 95% CI: 1.27–1.47) than for rectal cancer (RR = 1.18; 95% CI: 1.11–1.26; P < 0.001). Waist circumference specifically showed a 32% increased risk (RR = 1.32; 95% CI: 1.25–1.41). Studies using measured WC/WHR reported a higher risk (RR = 1.48; 95% CI: 1.36–1.61) than those using self-reported measures (RR = 1.26; 95% CI: 1.20–1.32; P < 0.001). No significant heterogeneity was found by exposure type (WC vs. WHR) or geographic region. Conclusions Central obesity is a significant and independent risk factor for colorectal cancer, with stronger associations observed for colon cancer than for rectal cancer and higher relative risks in men than in women. Visceral fat appears to play a critical role in colorectal carcinogenesis. Maintaining a healthy waist circumference through regular physical activity and a balanced diet remains a key strategy to reduce CRC risk.
SN - 1471-2407
ER -