Effect Factors Of The Prevalence Of Thyroid Nodules In Zhejiang Province

Objective:1. To find out the current status of iodine nutrition of community residents in Zhejiang Province to evaluate the level of iodine nutrition in different areas and groups of population.2. To assess the prevalence rate and distribution features of thyroid nodules among the community residents in Zhejiang Province.3. To explore the risk factors for thyroid nodules among the community residents in Zhejiang Province.Methods:1. The method of stratified cluster sampling was adopted,the residents of twenty-two communities in Zhejiang Province were selected. The cross-sectional survey,conducted by questionnaire,examination on thyroid and laboratory test,such as the test of urinary iodine,water iodine and the concentration of the iodine salt,had played positive roles in calculating the prevalence rate of thyroid nodules and the level of iodine nutrition.The distribution features of thyroid nodules was described,and the possible risk factors for thyroid nodules was analyzed with logistic regression.2. A case-control study was conducted among the subjects of the first part study.The cases were the informed consent patients with thyroid nodules,and the controls were the normal subjects, frequency matched with the case mainly by age,gender, region of residence. The study factor was analyzed with logistic regression.Result:1. The results of this cross-sectional survey about iodine nutrition are as follows: the median water iodine and salt iodine of Zhejiang was 2.42μg/L and 27.0 mg/kg respectively,79.54% iodized salts were coveraged, the ingesting rate of qualified iodized-salt was 76.65%,and the median urinary iodine of the population in zhejiang is 160.74μg/L, which of pregnancy was 137.99μg/L, the percentage which is less than 100μg/L was 25.92%, more than 300μg/L was 15.30%.and the proprotion of water,salt and other food in iodine intake was 1.71%,76.41% and 21.88% respectively.2. From the results of cross-sectional survey about thyroid nodules,we can see that the prevalence of thyroid nodules in Zhejiang was 21.78%, which of a single nodule was 11.75% ,that was higher than multiple nodules(10.03%);The prevalence of thyroid nodules in men was less than women, urban residents than rural, and both increased gradually with age; The residents in coastal areas had the highest prevalence of thyroid nodules, followed by sub-coastal areas, inland minimum; High education level, consumption of seafood habits, anger frequency, the history of thyroid disease and iodine deficiency were potentia risk factors for thyroid nodules in this surveyed population,which need to be confirmed by further case-control study.3. The results of multi-factor Logistic regression used to analyze the association between thyroid nodules and the related variables in cases-control study about thyroid nodules are as follows: working in the textile(OR=5.40),the history of contact with metal powder(OR=4.36), the family history of thyroid disease (OR=1.84),the history of receiving X-ray and CT diagnosis (OR=5.54,OR=3.03) were significant associated with thyroid nodules.in female,working in the textile(OR=2.60),the family history of thyroid disease (OR=2.30),the history of receiving X diagnosis (OR=14.15), younger age of first pregnancy(OR=2.38),contraception history (OR=1.66) and the history of hormone replacement therapy(OR=0.52)were significant associated with thyroid nodules.Conclution:1. The status of iodine nutrition in Zhejiang province in general is appropriate, but the level of iodine nutrition in pregnant women was less than the state, which should be cause for concern.2. The prevalence of thyroid nodules in Zhejiang Province was 21.78%, female prevalence was greater than men, and gradually increased with age, the elderly population should be the focus of prevention.3. It is demonstrated that working in the textile,the history of contact with metal powder,the family history of thyroid disease,the history of receiving X-ray and CT diagnosis were risk factors for thyroid nodules. In female,working in the textile,the family history of thyroid disease, the history of receiving X diagnosis, younger age of first pregnancy and contraception history were risk factors for thyroid nodules,the history of hormone replacement therapy was protective factors.