To reveal the variables responsible for the differences of fT3 and fT4 levels between patients with type 2 diabetes and controls, multiple regression analysis with backward stepwise selection was conducted using valuables as follows: age, sex, BMI, TSH, fT3 (for T4 analysis), fT4 (for fT3 analysis), TgAb, TPOAb, TRAb, HbA1c, glucose, CPR, and osteocalcin. The gene discussed is CD4; the disease is type 2 diabetes mellitus.