Demographic characteristics after multiple imputation
| Variable | Without PFO (n=2860) | With PFO (n=881) | SMD | P |
| Propensity score | 0.2337 (0.0361) | 0.2413 (0.0383) | 0.1993 | 0.0060 |
| Mean (SD) age, years | 51.09 (7.31) | 50.27 (7.53) | 0.1106 | 0.0038 |
| Gender, n (%) | 0.0339 | 0.3816 | ||
| Female | 2120 (74.13) | 666 (75.60) | ||
| Male | 740 (25.87) | 215 (24.40) | ||
| BMI, n (%) | 0.7874 | |||
| Underweight | 76 (2.65) | 21 (2.33) | 0.0204 | |
| Normal | 1451 (50.72) | 464 (52.62) | ||
| Overweight | 1051 (36.76) | 312 (35.38) | 0.0287 | |
| Obesity | 282 (9.88) | 85 (9.67) | 0.0076 | |
| Educational level, n (%) | 0.1878 | |||
| Primary | 940 (32.86) | 254 (28.84) | ||
| Middle | 1349 (47.18) | 439 (49.84) | 0.0533 | |
| High | 416 (14.56) | 140 (15.88) | 0.0368 | |
| Advanced | 154 (5.40) | 48 (5.44) | 0.0073 | |
| Smoking, n (%) | 476 (16.64) | 143 (16.20) | 0.0126 | 0.7564 |
| Alcohol, n (%) | 430 (15.03) | 134 (15.23) | 0.0077 | 0.8492 |
| Tea, n (%) | 801 (28.01) | 232 (26.29) | 0.0387 | 0.3286 |
| Coffee, n (%) | 36 (1.25) | 15 (1.68) | 0.0352 | 0.3917 |
| Sleep quality, mean (SD) | 3.82 (2.48) | 3.71 (2.46) | 0.0451 | 0.2691 |
| Anxiety, mean (SD) | 1.01 (2.28) | 1.10 (2.42) | 0.0355 | 0.3734 |
| Depression, mean (SD) | 1.03 (2.10) | 1.10 (2.14) | 0.0320 | 0.4232 |
| Family migraine, n (%) | 355 (12.41) | 141 (16.05) | 0.1042 | 0.1001 |
BMI, body mass index; PFO, patent foramen ovale; SMD, standardised mean difference.