Many studies suggest that TN is related to age; however,we failed to stratify age into different groups. It is possible that the prevalence of TN may increase with increasing age.Guo et al. have demonstrated that individuals >40 years of age have a higher prevalence of TN.20 Zheng et al. have suggested that advanced age contributes to the high rates of Ns in postmenopausal females.21 Another article has maintained that thyroid nodular disease increases with age,and that age itself is a risk factor for thyroid cancer.22