Concordance rates for varicose veins and haemorrhoids in MZ and DZ twins
| Phenotype | Twin type | Casewise | χ1 | p | ||
|---|---|---|---|---|---|---|
| Concordant unaffected | Discordant affected | Concordant affected | Concordance (95% CI) | |||
| CI, confidence interval. | ||||||
| Varicose veins | ||||||
| MZ | 301 | 68 | 68 | 0.67 (0.59 to 0.74) | ||
| DZ | 892 | 319 | 130 | 0.45 (0.40 to 0.50) | ||
| MZ-DZ | 0.22 | 22.4 | 2.2×10−6 | |||
| Haemorrhoids (excluding during pregnancy) | ||||||
| MZ | 246 | 175 | 182 | 0.68 (0.63 to 0.72) | ||
| DZ | 225 | 257 | 186 | 0.59 (0.55 to 0.64) | ||
| MZ-DZ | 0.08 | 6.5 | 0.01 | |||
| Haemorrhoids (including during pregnancy) | ||||||
| MZ | 246 | 261 | 348 | 0.73 (0.70 to 0.76) | ||
| DZ | 225 | 175 | 332 | 0.64 (0.61 to 0.67) | ||
| MZ-DZ | 0.09 | 13.7 | 2.1×10−4 | |||