Hazard ratios and model statistics of the shared frailty survival models (Models 0–2).

Estimate: estimated hazard ratios for the factors and estimated values for the model statistics (Model 0–2: adjusted by age, sex, and public health centre district); Qs = Quartiles, CI = confidence interval; trend p: p value of trend test; Explained geographical variance: percentage of reduction in Theta of fitted models compared to Model 0; Difference in AIC: the subtraction of AIC of fitted model from AIC of Model 0.