Table 4. Body mass index and risk of colorectal cancer overall and by tumor histopathological characteristics in the pooled cohorts.
| Body mass index (kg/m2) | Ptrend | Pheterogeneity† | |||||
|---|---|---|---|---|---|---|---|
|
| |||||||
| 18.5-22.4 | 22.5-24.9 | 25.0-27.4 | 27.5-29.9 | ≥30 | |||
| Total colorectal cancer | |||||||
| Person-years | 812884 | 951694 | 747717 | 407217 | 427160 | ||
| Cases, No. (n=1528) | 235 | 424 | 408 | 228 | 233 | ||
| Age-adjusted HR (95% CI) | 1 [Reference] | 1.22 (1.04, 1.44) | 1.39 (1.18, 1.64) | 1.46 (1.21, 1.75) | 1.62 (1.35, 1.95) | <0.001 | |
| Multivariable HR (95% CI)* | 1 [Reference] | 1.22 (1.04, 1.43) | 1.38 (1.17, 1.63) | 1.43 (1.19, 1.73) | 1.61 (1.33, 1.95) | <0.001 | |
|
| |||||||
| Poorly-differentiated foci | |||||||
| Absent | |||||||
| Cases, No. (n=1069) | 154 | 286 | 288 | 167 | 174 | ||
| Age-adjusted HR (95% CI) | 1 [Reference] | 1.27 (1.04, 1.55) | 1.52 (1.24, 1.85) | 1.65 (1.32, 2.07) | 1.88 (1.51, 2.35) | <0.001 | 0.006 |
| Multivariable HR (95% CI)* | 1 [Reference] | 1.27 (1.04, 1.55) | 1.50 (1.23, 1.84) | 1.63 (1.30, 2.04) | 1.87 (1.49, 2.34) | <0.001 | 0.006 |
| Present | |||||||
| Cases, No. (n=437) | 78 | 132 | 111 | 58 | 58 | ||
| Age-adjusted HR (95% CI) | 1 [Reference] | 1.13 (0.85, 1.50) | 1.13 (0.84, 1.52) | 1.08 (0.77, 1.53) | 1.17 (0.83, 1.65) | 0.51 | |
| Multivariable HR (95% CI)* | 1 [Reference] | 1.13 (0.85, 1.50) | 1.11 (0.83, 1.49) | 1.06 (0.75, 1.50) | 1.17 (0.82, 1.65) | 0.56 | |
|
| |||||||
| Overall tumor differentiation | |||||||
| Well/moderate | |||||||
| Cases, No. (n=1366) | 205 | 368 | 373 | 207 | 213 | ||
| Age-adjusted HR (95% CI) | 1 [Reference] | 1.21 (1.01, 1.44) | 1.45 (1.21, 1.72) | 1.51 (1.24, 1.84) | 1.70 (1.40, 2.07) | <0.001 | 0.03 |
| Multivariable HR (95% CI)* | 1 [Reference] | 1.20 (1.01, 1.43) | 1.43 (1.20, 1.70) | 1.48 (1.22, 1.81) | 1.69 (1.38, 2.06) | <0.001 | 0.04 |
| Poor | |||||||
| Cases, No. (n=149) | 29 | 51 | 30 | 20 | 19 | ||
| Age-adjusted HR (95% CI) | 1 [Reference] | 1.28 (0.81, 2.03) | 0.91 (0.54, 1.54) | 1.06 (0.59, 1.90) | 1.06 (0.59, 1.90) | 0.79 | |
| Multivariable HR (95% CI)* | 1 [Reference] | 1.28 (0.80, 2.03) | 0.92 (0.55, 1.55) | 1.05 (0.59, 1.87) | 1.07 (0.59, 1.91) | 0.80 | |
|
| |||||||
| Mucinous component | |||||||
| Absent (0%) | |||||||
| Cases, No. (n=875) | 142 | 244 | 233 | 124 | 132 | ||
| Age-adjusted HR (95% CI) | 1 [Reference] | 1.19 (0.97, 1.47) | 1.33 (1.07, 1.65) | 1.37 (1.07, 1.75) | 1.58 (1.24, 2.00) | <0.001 | 0.36 |
| Multivariable HR (95% CI)* | 1 [Reference] | 1.19 (0.97, 1.47) | 1.32 (1.06, 1.64) | 1.34 (1.05, 1.72) | 1.56 (1.23, 2.00) | <0.001 | 0.36 |
| 1% to 49% | |||||||
| Cases, No. (n=400) | 63 | 113 | 104 | 65 | 55 | ||
| Age-adjusted HR (95% CI) | 1 [Reference] | 1.18 (0.86, 1.61) | 1.32 (0.96, 1.82) | 1.51 (1.06, 2.14) | 1.38 (0.95, 1.98) | 0.03 | |
| Multivariable HR (95% CI)* | 1 [Reference] | 1.18 (0.86, 1.61) | 1.31 (0.95, 1.80) | 1.48 (1.04, 2.11) | 1.36 (0.94, 1.97) | 0.04 | |
| ≥50% | |||||||
| Cases, No. (n=164) | 21 | 44 | 43 | 20 | 36 | ||
| Age-adjusted HR (95% CI) | 1 [Reference] | 1.45 (0.86, 2.45) | 1.70 (1.00, 2.88) | 1.36 (0.73, 2.53) | 2.65 (1.54, 4.57) | 0.001 | |
| Multivariable HR (95% CI)* | 1 [Reference] | 1.46 (0.86, 2.46) | 1.68 (0.99, 2.86) | 1.34 (0.72, 2.49) | 2.63 (1.53, 4.54) | 0.001 | |
|
| |||||||
| Signet ring cell component | |||||||
| Absent | |||||||
| Cases, No. (n=1353) | 208 | 374 | 364 | 204 | 203 | ||
| Age-adjusted HR (95% CI) | 1 [Reference] | 1.22 (1.03, 1.45) | 1.40 (1.18, 1.67) | 1.48 (1.22, 1.80) | 1.62 (1.34, 1.97) | <0.001 | 0.67 |
| Multivariable HR (95% CI)* | 1 [Reference] | 1.22 (1.02, 1.45) | 1.39 (1.17, 1.66) | 1.46 (1.20, 1.78) | 1.61 (1.32, 1.97) | <0.001 | 0.67 |
| Present | |||||||
| Cases, No. (n=175) | 27 | 50 | 44 | 24 | 30 | ||
| Age-adjusted HR (95% CI) | 1 [Reference] | 1.25 (0.78, 2.01) | 1.30 (0.80, 2.12) | 1.26 (0.72, 2.19) | 1.60 (0.95, 2.71) | 0.13 | |
| Multivariable HR (95% CI)* | 1 [Reference] | 1.23 (0.77, 1.98) | 1.28 (0.79, 2.09) | 1.23 (0.70, 2.14) | 1.58 (0.93, 2.67) | 0.14 | |
*
Adjusted for the same set of covariates as in Table 2.
†
We assessed whether the magnitude of the subtype-specific associations had an increasing or decreasing ordinal trend according to the subtyping marker using a likelihood ratio test with one degree of freedom, and the statistical significance of this trend was presented as Pheterogeneity.
CI, confidence interval; HR, hazard ratio.