Multivariable models to show associations with SMM
| Unadjusted model | Model 1* | Model 2† | Model 3‡ | |
| OR (95% CI) | OR (95% CI) | OR (95% CI) | OR (95% CI) | |
| IMD quintile | ||||
| Most deprived 20% | 1.20 (1.14 to 1.25) | 1.16 (1.11 to 1.23) | 1.16 (1.10 to 1.22) | 1.13 (1.07 to 1.19) |
| More deprived 20–40% | 1.15 (1.09 to 1.20) | 1.12 (1.06 to 1.17) | 1.11 (1.06 to 1.17) | 1.10 (1.04 to 1.15) |
| Less deprived 40–60% | 1.10 (1.05 to 1.15) | 1.09 (1.03 to 1.15) | 1.09 (1.03 to 1.14) | 1.08 (1.02 to 1.13) |
| Less deprived 60–80% | 1.06 (1.01 to 1.12) | 1.07 (1.02 to 1.13) | 1.07 (1.01 to 1.13) | 1.06 (1.01 to 1.12) |
| Least deprived 80–100% | 1(ref) | 1(ref) | 1(ref) | 1(ref) |
| Ethnicity | ||||
| White | 1(ref) | 1(ref) | 1(ref) | 1(ref) |
| Black or Black British—Caribbean | 1.73 (1.51 to 1.99) | 1.69 (1.47 to 1.94) | 1.68 (1.46 to 1.93) | 1.66 (1.44 to 1.90) |
| Black or Black British—African | 1.89 (1.74 to 2.04) | 1.81 (1.67 to 1.96) | 1.86 (1.72 to 2.02) | 1.84 (1.70 to 2.00) |
| Asian or Asian British—Indian | 1.23 (1.13 to 1.33) | 1.19 (1.10 to 1.29) | 1.23 (1.13 to 1.33) | 1.26 (1.16 to 1.36) |
| Asian or Asian British—Pakistani | 1.47 (1.37 to 1.59) | 1.44 (1.33 to 1.55) | 1.47 (1.36 to 1.59) | 1.49 (1.38 to 1.61) |
| Asian or Asian British—Bangladeshi | 1.64 (1.45 to 1.85) | 1.60 (1.41 to 1.81) | 1.64 (1.45 to 1.86) | 1.68 (1.48 to 1.90) |
| Mixed | 1.22 (1.10 to 1.35) | 1.21 (1.09 to 1.33) | 1.22 (1.10 to 1.35) | 1.23 (1.11 to 1.36) |
| Other | 1.37 (1.31 to 1.44) | 1.33 (1.27 to 1.40) | 1.37 (1.31 to 1.44) | 1.41 (1.34 to 1.48) |
| Age group | ||||
| <20 | 1.20 (1.11 to 1.29) | 0.85 (0.79 to 0.92) | 0.86 (0.80 to 0.93) | 0.87 (0.81 to 0.94) |
| 20–25 | 1 to (ref) | 1(ref) | 1(ref) | 1(ref) |
| 25–30 | 1.24 (1.15 to 1.33) | 1.04 (0.99 to 1.08) | 1.04 (0.99 to 1.08) | 1.04 (1.00 to 1.09) |
| 30–35 | 1.27 (1.18 to 1.36) | 1.09 (1.04 to 1.14) | 1.09 (1.05 to 1.14) | 1.11 (1.06 to 1.16) |
| 35–40 | 1.37 (1.27 to 1.48) | 1.18 (1.12 to 1.25) | 1.17 (1.11 to 1.24) | 1.20 (1.13 to 1.26) |
| >40 | 1.72 (1.55 to 1.91) | 1.51 (1.38 to 1.65) | 1.48 (1.35 to 1.62) | 1.51 (1.38 to 1.65) |
| Pre-existing medical conditions§ | 1.38 (1.33 to 1.44) | 1.39 (1.33 to 1.45) | 1.35 (1.29 to 1.41) | |
| Pre-existing mental health diagnosis§ | 1.24 (1.16 to 1.32) | 1.17 (1.10 to 1.25) | 1.15 (1.08 to 1.24) | |
| Substance misuse or smoking§ | 1.06 (1.01 to 1.11) | 0.99 (0.94 to 1.04) | ||
| Obesity/overweight§ | 1.42 (1.37 to 1.46) | 1.40 (1.35 to 1.45) |
*Model 1 additional adjustment for age (in 5-year categories) and ethnicity (in eight categories).
†Model 2 additional adjustment for medical and psychological factors including pre-exisiting medical conditions and pre-exisiting mental health problems.
‡Model 3 additional adjustment health behaviours, obesity, smoking and substance misuse.
§See list of conditions included list in online supplemental table S2.
IMD, Index of Multiple Deprivation; SMM, severe maternal morbidity.