INS and diabetes mellitus: There were no significant associations between the TyG index and increased arterial stiffness participants aged less than 60 years (n = 1844), whose HbA1c was less than 7% (n = 1170), whose duration of diabetes was less than 5 years (n = 1498) and those with insulin therapy (n = 699), which may be because of the much smaller sample size (all P ≥ 0.05).