Ningbo thyroid dysfunction prevalence study： a cross-sectional survey in an employees-cohort

• Published in: Chinese medical journal 2010-07, Vol.123 (13), p.1673-1678
• Main Authors: Mao, Yu-Shan, Liu, Zhi-Min, Chen, Chang-Xi, Zhu, Zhong-Wei, Hong, Zhong-Li
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Cross-Sectional Studies; Female; Humans; Hyperthyroidism - epidemiology; Hyperthyroidism - metabolism; Hypothyroidism - epidemiology; Hypothyroidism - metabolism; Male; Middle Aged; Surveys and Questionnaires; Thyroid Diseases - epidemiology; Thyroid Diseases - metabolism; Thyroid Function Tests; Thyrotropin - metabolism; Young Adult; 促甲状腺激素; 功能障碍; 横断面调查; 甲状腺功能减退
• ISSN: 0366-6999; 2542-5641
• DOI: 10.3760/cma.j.issn.0366-6999.2010.13.011

Background The prevalence and the spectrum of thyroid dysfunction in the mainland of China are not adequately understood. We performed a population-based study to determine the prevalence of major thyroid dysfunctions including overt and subclinical hyper- and hypothyroidism in a stable cohort. Methods All active and retired employees aged 20 years and older （11 067） of Sinopec Zhenhai Refining ＆ Chemical Company in Ningbo participated in the cross-sectional survey with a questionnaire and blood samples. Results A total of 10 405 individuals attended for screening. Using biochemical definitions 95.5% were euthyroid. The prevalence of former diagnosed hyperthyroidism was 1.1% in females and 0.4% in males, hypothyroidism 1.7% and 0.3%, and thyroid surgery 1.2% and 0.3%, respectively. In both sex the prevalence increased with age. Twenty-four percent of individuals with thyroid surgery or medications had abnormal thyroid-stimulating hormone （TSH） levels. In individuals without a history of thyroid disease, the prevalence of pathological TSH values in females and males were TSH 〉10 mU/L 0.60% and 0.29%; TSH 4.8-9.9 mU/L 5.71% and 2.25%; TSH 〈0.3 mU/L 0.87% and 0.41%, respectively. Overt hyper- and hypothyroidism were uncommon （0.2%, 0.3%, respectively）. The prevalence of subclinical hyper- and hypothyroidism was 0.4% and 3.4%, respectively. Subclinical hypothyroidism was more common in females （male 2.4% vs. female 5.8%, P 〈0.001） and with increasing age （P 〈0.001）. Conclusions The prevalence of thyroid dysfunction is 4.5% in the cohort. Among individuals with thyroid medications or surgery, only 75.7% were within the normal range of TSH. These results indicate that thyroid dysfunction is common in Chinese adults.