Abstract: ObjectiveTo explore related risk factors of thyroid nodule in residents of Zhoushan Archipelago.MethodsThe residents were selected with random sampling and surveyed with a questionnaire and their thyroid conditions were assayed with B-mode ultrasound.The population-based case-control study was used to analyse the risk factors with logistic regression model.A total of 831 thyroid nodule cases were matched to 831 residents by gender,age,region,and occupation.ResultsThe annual income was a protective factor for thyroid nodule(P=0.014,odds ratio=0.875,95% confidence interval=0.589-0.998).Other factors such as dietetical conditions,iodine-salt intake,alcohol consumption,smoking,drinking tea,and the concentration of the urinary iodine had no significant correlation with thyroid nodule.ConclusionThere is no close relation between thyroid nodule and dietary habits,the leveles of iodine nutrition in the residents of Zhoushan Archipelago.But futher study on influencing factors of thyroid nodule is needed.