TABLE 2.
Hazard Ratios (HRs) and 95% CIs per fifth and specified unit increase in adiposity measures for the risk of inflammatory bowel disease (IBD).
| Cases | Person years | Minimally adjusted model HR (95% CI) | P | Fully adjusted model HR (95% CI) | P | |
|---|---|---|---|---|---|---|
| Inflammatory bowel disease | ||||||
| Body mass index | ||||||
| Per 5 kg/m2 | 1.11 (1.07, 1.15) | <0.001 | 1.06 (1.02, 1.10) | 0.004 | ||
| Q1 | 501 | 1,200,655 | Ref | Ref | ||
| Q2 | 558 | 1,201,876 | 1.06 (0.94, 1.20) | 0.317 | 1.05 (0.93, 1.19) | 0.409 |
| Q3 | 573 | 1,197,337 | 1.07 (0.95, 1.21) | 0.253 | 1.03 (0.92, 1.17) | 0.580 |
| Q4 | 629 | 1,193,695 | 1.17 (1.04, 1.32) | 0.008 | 1.09 (0.97, 1.23) | 0.152 |
| Q5 | 693 | 1,181,936 | 1.34 (1.19, 1.50) | <0.001 | 1.18 (1.04, 1.32) | 0.007 |
| P trend | <0.001 | 0.006 | ||||
| Waist circumference | ||||||
| Per 10 cm | 1.11 (1.08, 1.14) | <0.001 | 1.06 (1.03, 1.10) | <0.001 | ||
| Q1 | 406 | 1,115,916 | Ref | Ref | ||
| Q2 | 541 | 1,171,117 | 1.23 (1.08, 1.40) | 0.002 | 1.19 (1.04, 1.35) | 0.010 |
| Q3 | 579 | 1,200,035 | 1.25 (1.10, 1.43) | 0.001 | 1.18 (1.03, 1.34) | 0.017 |
| Q4 | 666 | 1,229,713 | 1.38 (1.21, 1.58) | <0.001 | 1.25 (1.09, 1.43) | 0.001 |
| Q5 | 762 | 1,258,719 | 1.54 (1.35, 1.76) | <0.001 | 1.30 (1.14, 1.49) | <0.001 |
| P trend | <0.001 | <0.001 | ||||
| Crohn's disease | ||||||
| Body mass index | ||||||
| Per 5 kg/m2 | 1.16 (1.09, 1.23) | <0.001 | 1.11 (1.04, 1.19) | 0.001 | ||
| Q1 | 169 | 1,197,764 | Ref | Ref | ||
| Q2 | 160 | 1,198,842 | 0.94 (0.76, 1.17) | 0.587 | 0.94 (0.76, 1.17) | 0.597 |
| Q3 | 167 | 1,194,974 | 0.99 (0.79, 1.22) | 0.895 | 0.97 (0.78, 1.20) | 0.781 |
| Q4 | 183 | 1,190,988 | 1.08 (0.88, 1.34) | 0.461 | 1.03 (0.83, 1.28) | 0.761 |
| Q5 | 236 | 1,179,593 | 1.41 (1.15, 1.72) | 0.001 | 1.28 (1.04, 1.57) | 0.018 |
| P trend | <0.001 | 0.008 | ||||
| Waist circumference | ||||||
| Per 10 cm | 1.17 (1.11, 1.23) | <0.001 | 1.12 (1.07, 1.18) | <0.001 | ||
| Q1 | 129 | 1,114,099 | Ref | Ref | ||
| Q2 | 171 | 1,168,671 | 1.30 (1.04, 1.64) | 0.024 | 1.26 (1.00, 1.59) | 0.046 |
| Q3 | 171 | 1,197,406 | 1.34 (1.06, 1.70) | 0.015 | 1.27 (1.00, 1.61) | 0.049 |
| Q4 | 211 | 1,226,699 | 1.67 (1.32, 2.11) | <0.001 | 1.53 (1.21, 1.94) | <0.001 |
| Q5 | 233 | 1,255,285 | 1.82 (1.44, 2.31) | <0.001 | 1.58 (1.25, 2.01) | <0.001 |
| P trend | 1.15 (1.09, 1.21) | <0.001 | 1.11 (1.06, 1.17) | <0.001 | ||
| Ulcerative colitis | ||||||
| Body mass index | ||||||
| Per 5 kg/m2 | 1.09 (1.04, 1.14) | <0.001 | 1.03 (0.99, 1.08) | 0.186 | ||
| Q1 | 332 | 1,199,615 | Ref | Ref | ||
| Q2 | 398 | 1,200,530 | 1.12 (0.97, 1.30) | 0.117 | 1.11 (0.95, 1.28) | 0.180 |
| Q3 | 406 | 1,195,714 | 1.12 (0.96, 1.29) | 0.140 | 1.07 (0.92, 1.24) | 0.395 |
| Q4 | 446 | 1,192,607 | 1.22 (1.06, 1.41) | 0.007 | 1.12 (0.97, 1.29) | 0.131 |
| Q5 | 457 | 1,181,077 | 1.30 (1.13, 1.50) | <0.001 | 1.13 (0.98, 1.31) | 0.101 |
| P trend | 1.06 (1.03, 1.10) | <0.001 | 1.02 (0.99, 1.06) | 0.136 | ||
| Waist circumference | ||||||
| Per 10 cm | 1.09 (1.05, 1.13) | <0.001 | 1.04 (1.00, 1.08) | 0.049 | ||
| Q1 | 277 | 1,115,083 | Ref | Ref | ||
| Q2 | 370 | 1,170,019 | 1.19 (1.02, 1.39) | 0.030 | 1.15 (0.98, 1.34) | 0.087 |
| Q3 | 408 | 1,198,972 | 1.21 (1.03, 1.42) | 0.022 | 1.13 (0.96, 1.32) | 0.144 |
| Q4 | 455 | 1,228,312 | 1.26 (1.07, 1.49) | 0.005 | 1.14 (0.96, 1.34) | 0.127 |
| Q5 | 529 | 1,257,155 | 1.42 (1.21, 1.66) | <0.001 | 1.19 (1.01, 1.40) | 0.041 |
| P trend | 1.08 (1.04, 1.12) | <0.001 | 1.03 (0.99, 1.07) | 0.107 | ||
Note: Minimally adjusted model: Cox model adjusted for age, sex and ethnicity; fully adjusted model: further adjusted for TDI, smoking status, drinking status, education, physical activities and diet index. P values with bold indicate statistically significant (P < 0.05).
Abbreviations: CI, confidence interval; IBD, inflammatory bowel disease; HR, hazard ratio; SD, standard deviation.