Table 1.
MR estimates from different methods of assessing the causal effect of IBD on BMDs
| BMDs | Step# | No. of SNP | IVW | MBE | WMM | MR-Egger | MR.RAPS | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| β (95%CI) | P value | Cochran Q statistics (df) | P value | β (95%CI) | P value | β (95%CI) | P value | Slope (95%CI) | P value | Intercept (Se) | P value | Cochran Q statistics (df) | P value | β (95%CI) | P value | |||
| IBD and TB-BMD | 3 | 119 | − 0.017 (− 0.029, − 0.0046) | 0.0067 | 146.2 (118) | 0.040 | − 0.0054 (− 0.031, 0.020) | 0.67 | − 0.0059 (− 0.024, 0.013) | 0.53 | − 0.016 (− 0.045, 0.013) | 0.29 | − 9.89e−5 (0.0016) | 0.95 | 146.20 (117) | 0.035 | − 0.016 (− 0.028, − 0.0028) | 0.017 |
| IBD and FN-BMD | 3 | 118 | − 0.019 (− 0.035, − 0.0032) | 0.018 | 140.57 (117) | 0.068 | − 0.049 (− 0.084, − 0.013) | 0.0079 | − 0.024 (− 0.047, − 0.00035) | 0.047 | − 0.0025 (− 0.039, 0.034) | 0.90 | − 0.0020 (0.0020) | 0.33 | 139.42 (116) | 0.068 | − 0.018 (− 0.034, − 0.0014) | 0.034 |
| IBD and LS-BMD | 3 | 120 | − 0.012 (− 0.030, 0.0053) | 0.17 | 135.03 (119) | 0.15 | − 0.034 (− 0.070, 0.0023) | 0.069 | − 0.029 (− 0.056, − 0.0018) | 0.037 | − 0.015 (− 0.057, 0.027) | 0.48 | 0.00032 (0.0023) | 0.89 | 125.00 (118) | 0.14 | − 0.013 (− 0.032, 0.0047) | 0.15 |
| IBD and FA-BMD | 3 | 124 | − 0.026 (− 0.057, 0.0058) | 0.11 | 142.47 (123) | 0.11 | − 0.015 (− 0.084, 0.055) | 0.68 | − 0.017 (− 0.064, 0.029) | 0.46 | 0.012 (− 0.063, 0.086) | 0.76 | − 0.0044 (0.0041) | 0.29 | 141.14 (122) | 0.11 | − 0.028 (− 0.060, 0.0049) | 0.095 |
| IBD and TB-BMD(R*) | 3 | 102 | − 0.016 (− 0.027, − 5.46e−3) | 0.0033 | 102.48 (101) | 0.44 | − 0.012 (− 0.037, 1.28e−2) | 0.35 | − 0.012 (− 0.030, 5.82e−3) | 0.19 | − 0.026 (− 0.052, − 9.06e−5) | 0.052 | 0.0012 (0.0015) | 0.42 | 101.82 (100) | 0.43 | − 0.016 (− 0.027, − 4.39e−3) | 0.0064 |
| IBD and FN-BMD(R*) | 3 | 100 | − 0.014 (− 0.030, 0.0014) | 0.074 | 113.58 (99) | 0.15 | − 0.042 (− 0.078, − 0.0054) | 0.027 | − 0.028 (− 0.051, − 0.0044) | 0.020 | − 0.022 (− 0.058, 0.015) | 0.24 | 0.00094 (0.0021) | 0.66 | 113.36 (98) | 0.14 | − 0.015 (− 0.032, 0.0021) | 0.086 |
| IBD and LS-BMD(R*) | 3 | 101 | 0.00062 (− 0.018, 0.020) | 0.95 | 122.96 (100) | 0.059 | − 0.021 (− 0.056, 0.015) | 0.27 | − 0.022 (− 0.051, 0.0076) | 0.15 | − 0.030 (− 0.073, 0.013) | 0.18 | 0.0039 (0.0025) | 0.13 | 120.13 (99) | 0.073 | 0.0023 (− 0.018, 0.022) | 0.82 |
| IBD and FA-BMD(R*) | 3 | 105 | − 0.026 (− 0.058, 0.0049) | 0.098 | 116.14 (104) | 0.20 | − 0.012 (− 0. 082, 0.058) | 0.75 | − 0.011 (− 0.059, 0.037) | 0.65 | − 0.0017 (− 0.076, 0.073) | 0.96 | − 0.0031 (0.0044) | 0.48 | 115.56 (103) | 0.19 | − 0.028 (− 0.062, 0.0051) | 0.097 |
Step#: 3, MR analysis after removing all the SNPs (with P value less than 1 in MR-PRESSO outlier test); R*, in replication practice
TB-BMD total body bone mineral density, FN-BMD femoral neck bone mineral density, LS-BMD lumbar spine bone mineral density, FA-BMD forearm bone mineral density, β beta coefficient, Se standard error, SNP single nucleotide polymorphism, MR Mendelian randomization, IVW inverse variance weighting, MR-PRESSO MR-Pleiotropy RESidual Sum and Outlier method, MBE mode-based estimate method, WMM weighted median method, MR.RAPS robust adjusted profile score