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Table 4 Comparison of ACE models in both birth cohorts

From: Interplay between heritability of smoking and environmental conditions? A comparison of two birth cohorts

  Compare cohorts -2 LL Df Versus Χ2 Δ df p
1 Full ACE 5676.915 4990     
2 Constrain Rcdos at 1 5677.127 4992 1 0.212 2 0.8994
3 EQ ACE for men over cohorts 5677.825 4995 2 0.698 3 0.8737
4 EQ ACE for women over cohorts 5677.692 4995 2 0.565 3 0.9044
5 EQ ACE for both sexes over cohorts 5678.229 4998 2 1.102 6 0.9814
6 No sex differences in contributions of A,C,E 5688.117 5001 5 9.888 3 0.0195
7 Drop A 5718.180 5002 6 39.951 1 < 0.0001
8 Drop C 5695.529 5002 6 7,412 1 0.0064
  1. Full ACE: the influence of A, C and E factors is estimated separately for men and women and for both cohorts. The shared environmental correlation (Rc) in DZ twins of opposite sex (DOS) is estimated as a free parameter. Model 2: test for qualitative sex differences (Rcdos is fixed at 1). Model 3: ACE in cohort 1993-1995 is equalized to ACE in cohort 2009-2010 for men. Model 4: ACE in cohort 1993-1995 is equalized to ACE in cohort 2009-2010 for women. Model 5: ACE in cohort 1993-1995 is equalized to ACE in cohort 2009-2010 for men and women simultaneously. Model 6: ACE for men is equalized to ACE for women. Model 7: Additive genetics effects (A) are dropped. Model 8: Shared environmental influences (C) are dropped