BACKGROUND: Colorectal cancer is the second most common cause of death and illness in developed countries. Previous reviews have suggested that obesity may be associated with 30% to 60% greater risk of colorectal cancer, but little consideration was given to the possible effect of publication bias on the reported association. METHODS: Relevant studies were identified through EMBASE and MEDLINE. Studies were included if they had published quantitative estimates of the association between general obesity [defined here as body mass index (BMI) > or = 30 kg/m(2)] and central obesity (measured using waist circumference) and colorectal cancer. Random-effects meta-analyses were done, involving 70,000 cases of incident colorectal cancer from 31 studies, of which 23 were cohort studies and 8 were case-control studies. RESULTS: After pooling and correcting for publication bias, the estimated relative risk of colorectal cancer was 1.19 [95% confidence interval (95% CI), 1.11-1.29], comparing obese (BMI > or = 30 kg/m(2)) with normal weight (BMI <25 kg/m(2)) people; and 1.45 (95% CI, 1.31-1.61), comparing those with the highest, to the lowest, level of central obesity. After correcting for publication bias, the risk of colorectal cancer was 1.41 (95% CI, 1.30-1.54) in men compared with 1.08 (95% CI, 0.98-1.18) for women (P(heterogeneity) <0.001). There was evidence of a dose-response relationship between BMI and colorectal cancer: for a 2 kg/m(2) increase in BMI, the risk of colorectal cancer increased by 7% (4-10%). For a 2-cm increase in waist circumference, the risk increased by 4% (2-5%). CONCLUSIONS: Obesity has a direct and independent relationship with colorectal cancer, although the strength of the association with general obesity is smaller than previously reported.
BACKGROUND:Colorectal cancer is the second most common cause of death and illness in developed countries. Previous reviews have suggested that obesity may be associated with 30% to 60% greater risk of colorectal cancer, but little consideration was given to the possible effect of publication bias on the reported association. METHODS: Relevant studies were identified through EMBASE and MEDLINE. Studies were included if they had published quantitative estimates of the association between general obesity [defined here as body mass index (BMI) > or = 30 kg/m(2)] and central obesity (measured using waist circumference) and colorectal cancer. Random-effects meta-analyses were done, involving 70,000 cases of incident colorectal cancer from 31 studies, of which 23 were cohort studies and 8 were case-control studies. RESULTS: After pooling and correcting for publication bias, the estimated relative risk of colorectal cancer was 1.19 [95% confidence interval (95% CI), 1.11-1.29], comparing obese (BMI > or = 30 kg/m(2)) with normal weight (BMI <25 kg/m(2)) people; and 1.45 (95% CI, 1.31-1.61), comparing those with the highest, to the lowest, level of central obesity. After correcting for publication bias, the risk of colorectal cancer was 1.41 (95% CI, 1.30-1.54) in men compared with 1.08 (95% CI, 0.98-1.18) for women (P(heterogeneity) <0.001). There was evidence of a dose-response relationship between BMI and colorectal cancer: for a 2 kg/m(2) increase in BMI, the risk of colorectal cancer increased by 7% (4-10%). For a 2-cm increase in waist circumference, the risk increased by 4% (2-5%). CONCLUSIONS:Obesity has a direct and independent relationship with colorectal cancer, although the strength of the association with general obesity is smaller than previously reported.
Authors: Gertraud Maskarinec; Brook E Harmon; Melissa A Little; Nicholas J Ollberding; Laurence N Kolonel; Brian E Henderson; Loic Le Marchand; Lynne R Wilkens Journal: Cancer Causes Control Date: 2015-09-10 Impact factor: 2.506
Authors: Tim Y Hou; Laurie A Davidson; Eunjoo Kim; Yang-Yi Fan; Natividad R Fuentes; Karen Triff; Robert S Chapkin Journal: Annu Rev Nutr Date: 2016-07-17 Impact factor: 11.848
Authors: Dawn Q Chong; Raaj S Mehta; Mingyang Song; Dmitriy Kedrin; Jeffrey A Meyerhardt; Kimmie Ng; Kana Wu; Charles S Fuchs; Edward L Giovannucci; Shuji Ogino; Andrew T Chan Journal: Cancer Prev Res (Phila) Date: 2015-09-17
Authors: Elizabeth T Jacobs; Dennis J Ahnen; Erin L Ashbeck; John A Baron; E Robert Greenberg; Peter Lance; David A Lieberman; Gail McKeown-Eyssen; Arthur Schatzkin; Patricia A Thompson; María Elena Martínez Journal: Am J Epidemiol Date: 2009-01-15 Impact factor: 4.897
Authors: Andrea N Burnett-Hartman; Michael N Passarelli; Scott V Adams; Melissa P Upton; Lee-Ching Zhu; John D Potter; Polly A Newcomb Journal: Am J Epidemiol Date: 2013-03-03 Impact factor: 4.897