Table 3.
Estimated genetic and environmental parameters for kidney stones in the Washington State Twin Registry adjusted for age
| Estimates of variance components (95% confidence intervals)a | Test of model fit | ||||||
|---|---|---|---|---|---|---|---|
| Modelb | Additive genetics (A) | Common environment (C) | Unique environment (E) | Δχ2 | df | ΔP | ΔAICc |
| All twins | |||||||
| ACE | 0.52 (0.32–0.59) | 0.00 (0.00–0.18) | 0.48 (0.41–0.55) | — | — | — | — |
| AE | 0.52 (0.45–0.59) | — | 0.48 (0.41–0.55) | 0.0 | 1 | 1.0 | −2.0 |
| CE | — | 0.44 (0.37–0.50) | 0.56 (0.50–0.63) | 17.0 | 1 | <0.05 | 15.0 |
| Male/Male pairs | |||||||
| ACE | 0.57 (0.23–0.68) | 0.00 (0.00–0.31) | 0.43 (0.32–0.54) | — | — | — | — |
| AE | 0.57 (0.46–0.68) | — | 0.43 (0.32–0.54) | 0.0 | 1 | 1.0 | −2.0 |
| CE | — | 0.48 (0.37–0.58) | 0.52 (0.42–0.63) | 8.8 | 1 | <0.05 | 6.8 |
| Female/Female pairs | |||||||
| ACE | 0.46 (0.17–0.56) | 0.00 (0.00–0.25) | 0.54 (0.44–0.64) | — | — | — | — |
| AE | 0.46 (0.36–0.56) | — | 0.54 (0.44–0.64) | 0.00 | 1 | 1.00 | −2.0 |
| CE | — | 0.38 (0.29–0.47) | 0.62 (0.53–0.71) | 8.2 | 1 | <0.05 | 6.2 |
a
Proportion of variance explained by additive genetics, common environment, and unique environment according to each model.
b
ACE refers to the model including additive genetics (A), common environment (C), and unique environment (E). AE includes only additive genetics and unique environment, and CE common and unique environment; reduced models are compared with ACE.
c
Akaike’s information criterion (AIC) is a global measure of goodness of fit; best-fitting models are shown in bold.