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Table 2 Number of cases, concordant measures and intraclass correlations for the study measures

From: The relationships between IBS and perceptions of physical and mental health—a Norwegian twin study

Measure Cases, N (%) Concordant* pairs, n (%) Discordant **pairs, n (%) Probandwise concordance rate, % (95% CI) Intraclass correlations (95% CI)
Total m f MZ DZ MZ DZ MZ DZ MZ DZ
++ − − ++ − −
SRH              
 Physical 987 (18.8) 396 (17.2) 591 (20.1) 81 (8.1) 677 (67.6) 33 (3.6) 618 (67.0) 225 (22.5) 256 (27.7) 41.2 (35.7;48.0) 20.5 (14.6;26.4) 0.48 (0.43;0.52) 0.07 (0.01;0.13)
 Mental 376 (7.3) 134 (6.0) 242 (8.4) 17 (1.7) 821 (81.9) 6 (0.7) 753 (81.6) 115 (11.5) 101 (10.9) 22.8 (13.8;31.8) 10.6 (2.8;18.4) 0.39 (0.33;0.44) 0.14 (0.08;0.20)
Health hinders activities              
 Physical 742 (14.5) 281 (12.6) 461 (16.1) 42 (4.2) 699 (69.8) 26 (2.8) 645 (69.9) 188 (18.8) 187 (20.3) 30.9 (23.7;38.0) 21.8 (14.8;28.7) 0.38 (0.32;0.43) 0.20 (0.14;0.26)
 Mental 326 (6.5) 123 (5.6) 203 (7.2) 49 (4.9) 786 (78.4) 5 (0.5) 738 (80.0) 106 (10.6) 76 (8.2) 11.7 (3.8;19.5) 11.6 (2.3;20.9) 0.17 (0.11;0.23) 0.23 (0.17;0.29)
IBS 575 (10.9) 174 (7.5) 401 (13.5)   29 (2.9)   15 (1.6) 168 (16.8) 175 (19.0) 25.7 (18.1;33.2) 14.6 (8.0;21.2) 0.35 (0.29;0.40) 0.10 (0.04;0.17)
  1. *A twin pair was considered to be concordant for a health measure if both twins scored either 0 or 1 on the respective measure.
  2. **Discordance for SRH and the measures of health interfering with daily activities was based on the respective dichotomized measures