Table 3 Results of meta-analysis set 2

Studies (k)

43

10

47

27 included in [10]

5 included in [10]

28 included in [10]

3 excluded from [10]

5 new studies

3 excluded from [10]

13 new studies

16 new studies

Individuals in total (n)

63,295

Individuals per comparison (n)

59,973

28,511

63,181

MZ twins (n)

25,957

10,164

27,203

DZ twins (n)

34,016

18,347

35,978

Prevalence in MZ twins

11.45% (n = 2971)

1.83% (n = 186)

12.08% (n = 3286)

Prevalence in DZ twins

11.82% (n = 4019)

3.26% (n = 599)

13.29% (n = 4780)

OR [95% CI]

0.98 [0.89, 1.07]

0.96 [0.46, 1.99]

1.01 [0.91, 1.12]

z

− 0.51

− 0.11

0.13

Heterogeneity among studies

Q(42) = 74.08**

Q(9) = 100.52***

Q(46) = 149.78***

I² = 36.00%

I² = 86.33%

I² = 57.63%

Tau² = 0.02

Tau² = 0.88

Tau² = 0.05