Table 2.
Associations of maternal pre-pregnancy body mass index and paternal body mass index with the risk of type 1 diabetes
| Parent | Study | Exposure | Person-years | Events | Unadjusted HR (95% CI) | Adjusted HR (95% CI) | Test of heterogeneity (p-value) |
|---|---|---|---|---|---|---|---|
| Mother | MoBa | Continuous | 896 679 | 293 | 1.05 (1.03, 1.08) | 1.05 (1.02, 1.07) | |
| Underweight | 26 400 | 9 | 1.31 (0.67, 2.56) | 1.33 (0.68, 2.59) | |||
| Normal weight | 588 534 | 158 | 1 | 1 | |||
| Overweight | 197 983 | 88 | 1.64 (1.25, 2.15) | 1.60 (1.21, 2.10) | |||
| Obese | 83 762 | 38 | 1.67 (1.17, 2.40) | 1.57 (1.09, 2.27) | |||
| DNBC | Continuous | 722 194 | 206 | 1.01 (0.97, 1.04) | 1.00 (0.96, 1.03) | ||
| Underweight | 37 816 | 11 | 1.28 (0.69, 2.37) | 1.30 (0.70, 2.40) | |||
| Normal weight | 472 585 | 138 | 1 | 1 | |||
| Overweight | 127 823 | 33 | 0.79 (0.54, 1.17) | 0.75 (0.51, 1.11) | |||
| Obese | 83 970 | 24 | 1.41 (0.91, 2.18) | 1.18 (0.73, 1.88) | |||
| Combined | Continuous | 1 618 873 | 499 | 1.03 (0.99, 1.07) | 1.03 (0.98, 1.08) | 0.025 | |
| Underweight | 64 216 | 20 | 1.29 (0.82, 2.04) | 1.31 (0.84, 2.07) | 0.961 | ||
| Normal weight | 1 061 119 | 296 | 1 | 1 | NA | ||
| Overweight | 325 806 | 121 | 1.15 (0.56, 2.36) | 1.11 (0.53, 2.33) | 0.002 | ||
| Obese | 167 732 | 62 | 1.56 (1.18, 2.06) | 1.41 (1.06, 1.89) | 0.350 | ||
| Father | MoBa | Continuous | 896 679 | 293 | 1.06 (1.02, 1.10) | 1.05 (1.01, 1.09) | |
| Underweight | 1868 | 1 | 1.97 (0.27, 14.10) | 1.89 (0.26, 13.75) | |||
| Normal weight | 402 983 | 113 | 1 | 1 | |||
| Overweight | 405 868 | 136 | 1.19 (0.92, 1.54) | 1.17 (0.90, 1.51) | |||
| Obese | 85 961 | 43 | 1.78 (1.24, 2.57) | 1.67 (1.15, 2.43) | |||
| DNBC | Continuous | 722 194 | 206 | 1.01 (0.97, 1.06) | 1.01 (0.97, 1.06) | ||
| Underweight | 3824 | 1 | 1.22 (0.17, 8.73) | 1.21 (0.17, 8.63) | |||
| Normal weight | 351 465 | 104 | 1 | 1 | |||
| Overweight | 304 472 | 82 | 1.04 (0.77, 1.40) | 1.06 (0.79, 1.43) | |||
| Obese | 62 433 | 19 | 1.34 (0.81, 2.21) | 1.40 (0.85, 2.32) | |||
| Combined | Continuous | 1 618 873 | 499 | 1.04 (0.99, 1.09) | 1.03 (0.99, 1.07) | 0.19 | |
| Underweight | 5692 | 2 | 1.55 (0.38, 6.25) | 1.51 (0.37, 6.09) | 0.75 | ||
| Normal weight | 754 448 | 217 | 1 | 1 | NA | ||
| Overweight | 710 340 | 218 | 1.12 (0.92, 1.37) | 1.12 (0.92, 1.36) | 0.62 | ||
| Obese | 148 394 | 62 | 1.61 (1.20, 2.17) | 1.51 (1.11, 2.04) | 0.72 |
Maternal pre-pregnancy body mass index adjusted for maternal age, parity, education, smoking status during pregnancy and diabetes (type 1 in MoBa and all types in DNBC). Paternal body mass index adjusted for paternal age, education, smoking (paternal smoking in MoBa and maternal partner smoking in DNBC) and type 1 diabetes (MoBa only). Multiple imputation of missing exposure and covariate information using chained equations. A total of 20 datasets were imputed.