An Epidemiological Investigation Of Thyroid Dysfunction In Adult Residents In Dalian

Background and Objective:In 2010,the first nationwide thyroid disease epidemiology survey data of China was released at the ninth Annual Meeting of Chinese Society of Endocrinology.The results showed that the prevalence of thyroid disease had shown an obvious increase.Thyroid disease had become the second critical disease in the areas of endocrinology.Under the support of the special funds of National Health and Family Planning Commission,the nationwide epidemiological investigation of thyroid disease and iodine nutritional status began in 2014.Our research center had investigated the thyroid disease conditions among urban and rural adult residents in accordance with the unified project requirement in Dalian.Our study aimed to know the condition and epidemiology features of thyroid dysfunction and positive thyroid autoantibodies among urban and rural adult residents in Dalian through screening for the thyroid function,thyroid peroxidase antibody,thyroglobulin antibody and urinary iodine level,and to know the iodine nutritional status among residents in Dalian.Methods:During May to September in 2015,a cluster random sampling method was used to recruit adults aged over 18 years old in urban and rural areas of Dalian.A standard questionnaire in Chinese was administered to all study participants.Venous blood from the participants’ elbow was collected and centrifuged.All participants needed to collect 10ml urine.The serum and urine were stored at minus 20 degrees Celsius.The blood samples and urine samples were detected separately in Institute of Endocrinology of Chinese Medical Sciences University and the Centers for Disease Control of Liaoning province.Thyroid stimulating hormone,thyroid peroxidase antibody,thyroglobulin antibody and urinary iodine,were tested.If the testing TSH was high(>4.2mIU/L),FT4 was added to be tested.If TSH was low(<0.27mIU/L),FT4 and FT3 were added to be tested.The urine samples were used to detect urine iodine level.608～10 years old school-aged children were selected randomly in each urban and rural areas to detect urine iodine level.Database was set up by EpiData 3.1 data software,and statistical analysis was performed using the SPSS(Version 17.0).Result:(1)The crude prevalence of total thyroid dysfunction among adult residents in Dalian was 10.6%and the standardized prevalence was 9.1%.The prevalence of clinical hyperthyroidism,subclinical hyperthyroidism,clinical hypothyroidism and subclinical hypothyroidism were 0.7%,0.6%,0.2%and 9.0%.The crude prevalence of thyroid dysfunction in urban areas was 11.0%and the standardized prevalence was 9.3%,while in rural areas they were 10.1%and 8.8%.Whether in urban or rural areas,the prevalence of subclinical hypothyroidism was significantly higher than that of clinical hyperthyroidism,subclinical hyperthyroidism and clinical hypothyroidism.The prevalence of thyroid dysfunction and subclinical hypothyroidism of female residents were higher than those of male residents(P<0.05).(2)There was no significant difference in the prevalence of total thyroid dysfunction and its four different types between urban and rural residents(P>0.05),and between male residents from urban and rural areas(P>0.05),and between female residents from urban and rural areas(P>0.05).There were differences in the prevalence of total thyroid dysfunction and subclinical hypothyroidism among different age groups in Dalian.The prevalence of total thyroid dysfunction and subclinical hypothyroidism in the age group over 70 was significantly higher than those in 18～29,30～39,40～49 age groups(P<0.05).There was difference in the prevalence of subclinical hypothyroidism among different age groups in male residents,while there was no difference in female residents.In male residents,the prevalence of subclinical hypothyroidism in the age group over 70 was higher than that in 30～39,40～49 age groups(P<0.05).In the 30～39,40～49 age groups in urban areas and the 30～3 9 age group in rural areas,the prevalence of subclinical hypothyroidism of female residents was higher than that of male residents in the same age group(P<0.05).(3)The crude positive rate of TPOAb in Dalian was 9.7%and the standardized positive rate was 8.4%.The crude positive rate of TgAb in Dalian was 10.1%and the standardized positive rate was 8.7%.The crude positive rates of TPOAb and TgAb in urban areas were 10.3%and 10.7%,and the standardized positive rates were 8.8%and 9.2%.The crude positive rates of TPOAb and TgAb in rural areas were 9.0%and 9.4%,and the standardized positive rates were 8.0%and 8.1%.Whether in urban or rural areas,the positive rates of TPOAb and TgAb in female residents were both higher than those in male residents(P<0.05).There were no differences in the positive rate of TPOAb and TgAb between urban or rural areas,and between male residents from urban and rural areas,and between female residents from urban and rural areas.The prevalence of thyroid dysfunction and the TSH level in residents who had positive TPOAb and TgAb were significantly higher than those in residents who had negative TPOAb and TgAb(P<0.05).(4)There were no differences in urinary iodine level between male and female residents in urban areas,between male and female residents in rural areas.There were also no differences in urinary iodine level between male residents from urban and rural areas,and between female residents from urban and rural area,and between school-aged children from urban and rural areas(P>0.05).There was no difference in urinary iodine level among hyperthyroidism group,normal thyroid function group and hypothyroidism group(P>0.05).Conclusion:1.The standardized prevalence of thyroid dysfunction among adult residents in Dalian was 9.1%.The prevalence of clinical hyperthyroidism,subclinical hyperthyroidism,clinical hypothyroidism and subclinical hypothyroidism were 0.7%,0.6%,0.2%and 9.0%.Thyroid dysfunction was given priority to with subclinical hypothyroidism.The prevalence of thyroid dysfunction and subclinical hypothyroidism in female residents were higher than those in male residents.The prevalence of thyroid dysfunction and subclinical hypothyroidism in the age group over 70 was significantly higher than those in 18～29,30～39,40～49 age groups.2.The standardized positive rate of TPOAb among adult residents in Dalian was 8.4%and the standardized positive rate of TgAb was 8.7%.The positive rate of thyroid autoantibodies in female residents was significantly higher than that in male residents.3.The prevalence of thyroid dysfunction and the TSH level in residents who had positive TPOAb and TgAb were significantly higher than those in residents who had negative TPOAb and TgAb.There was no difference in urinary iodine level among hyperthyroidism group,normal thyroid function group and hypothyroidism group.4.The iodine nutritional status among residents in Dalian was adequate iodine nutrition.