TABLE 2.
ESTIMATES OF PROBANDWISE CONCORDANCE RATES, AND TETRACHORIC CORRELATIONS, FOR CHRONIC BRONCHITIS
| Twin Group | Concordant Unaffected | Discordant | Concordant Affected | Probandwise Concordance Rate (SE) | Tetrachoric Correlation (SE) |
|---|---|---|---|---|---|
| Total sample | |||||
| MZ | 3,699 | 414 | 65 | 0.239 (0.024) | 0.445 (0.042) |
| DZ | 10,209 | 1,368 | 93 | 0.120 (0.011) | 0.178 (0.031) |
| Younger than 60 yr | |||||
| MZ | 2,485 | 245 | 40 | 0.246 (0.032) | 0.477 (0.052) |
| DZ | 6,726 | 743 | 35 | 0.086 (0.014) | 0.123 (0.045) |
| 60 yr or older | |||||
| MZ | 1,214 | 169 | 25 | 0.228 (0.038) | 0.388 (0.070) |
| DZ | 3,483 | 625 | 58 | 0.157 (0.018) | 0.197 (0.044) |
| Sex | |||||
| MZ M | 1,625 | 148 | 28 | 0.275 (0.041) | 0.531 (0.061) |
| MZ F | 2,074 | 266 | 37 | 0.218 (0.030) | 0.385 (0.056) |
| DZ M | 2,351 | 253 | 14 | 0.100 (0.025) | 0.173 (0.074) |
| DZ F | 2,826 | 423 | 32 | 0.131 (0.021) | 0.180 (0.055) |
| DZ OS | 5,032 | 692 | 47 | 0.120 (0.016) | 0.175 (0.044) |
Definition of abbreviations: DZ = dizygotic; DZ OS = dizygotic opposite-sex twins; F = female; M = male; MZ = monozygotic.