Case-control analysis of the association between socioeconomic variables and gastric bypass surgery
| Variable | OR with 95% CI | P value |
| Education | ||
| Elementary school | Ref | <0.001 |
| Upper secondary school | 1.33 (1.18 to 1.51) | |
| College level | 1.42 (1.29 to 1.57) | |
| Income | ||
| Quartile 1 | 1.00 (1.00 to 1.00) | <0.001 |
| Quartile 2 | 1.37 (1.22 to 1.53) | |
| Quartile 3 | 1.76 (1.57 to 1.97) | |
| Quartile 4 | 1.94 (1.72 to 2.18) | |
| Marital status | ||
| Single | Ref | <0.001 |
| Married | 1.51 (1.37 to 1.66) | |
| Divorced | 1.65 (1.46 to 1.86) | |
| Widowed | 0.88 (0.67 to 1.15) | |
| Country of birth | ||
| Sweden | Ref | 0.007 |
| Europe (except Sweden) | 0.84 (0.73 to 0.95) | |
| Rest of the world | 0.87 (0.77 to 1.00) |
Statistical differences within groups were tested by a logistic regression model.