In multiple logistic regression analysis comparing pPTH with non-PTH patients, older age (OR 1.06, 95% Cl 1.01-1.13, p = 0.034) and insomnia after injury (OR 12.3, 95% Cl 2.79-54.13, p = 0.001) were independent risk factors for pPTH. The gene discussed is PTH; the disease is insomnia.