These findings reclassified 10

These findings reclassified 10.8% of adults as having supranormal TSH levels who were categorized as normal TSH levels according to the NACB criteria. A very high RI of TSH with 0.74 to 7.04 mIU/L established based on the NACB criteria was found in this populace, which is comparable to the TSH range of 0.62 to 6.84 mIU/L recently reported by a study from South Korea and is presumably due to the high iodine intake in both countries [25]. among those with UIC 300?g/L, and ?12.15% (?13.02% to ?11.28%) among non-smokers. For subnormal TSH, with the highest absolute difference of 3.17% (2.74% AZD8055 to 3.61%) observed among regular smokers, 3.11% (2.49% to 3.74%) among the elderly, and 2.53% (2.29% to 2.77%) among those with BMI 25. Interpretation For adults in China, the NACB standard RI of TSH reveals a lower estimated prevalence of supranormal TSH levels than the kit-recommended RI. Because of the public health significance of overt and subclinical hypothyroidism and the very large populace base in AZD8055 China, the TSH RI should be further assessed. Funding National Health Commission of the People’s Republic of China and National Natural Science Foundation of China. strong class=”kwd-title” Keywords: Prevalence, Thyroid, Abnormal TSH, Reference interval Research in context Evidence before this study We searched PubMed for studies published up to 1 1 Oct 2020 with the search terms abnormal TSH and China and reference interval with no language or date restrictions. The estimated changes in abnormal thyroid-stimulating hormone (TSH) prevalence among adults in China following application of the kit-recommended and National Academy of Clinical Biochemistry (NACB) standard reference interval (RI) was unknown. Added value of this study Using data from a nationally representative survey conducted in China, the estimated prevalence of abnormal TSH levels was 15.33% according to the kit-recommended RI; this value is usually 8.45% higher than that according to the NACB standard RI (6.89%). Implications of all the available evidence Implementing the NACB standard RI of TSH results in a lower estimated prevalence of abnormal TSH levels; the TSH RI should be further assessed to avoid overdiagnosis and overtreatment. Alt-text: Unlabelled box 1.?Introduction Thyroid dysfunction has multiple effects on public health. Previous research indicates that a large proportion of people with thyroid dysfunction are unaware of their condition [1]. In the absence of pituitary or hypothalamic disease, the thyroid-stimulating hormone (TSH) test is the best diagnostic tool for thyroid dysfunction and is recommended as a first-line test in diagnostic algorithms [2]. Supranormal TSH levels have been reported to be associated with an increased risk of higher serum lipid levels and atherosclerosis [3], [4], [5]. In addition, subnormal TSH levels have been related to increased risks of atrial fibrillation, fractures, and cardiovascular mortality [6], [7], [8], [9]. Some professional thyroid societies recommend screening for thyroid dysfunction in high-risk populations (such as pregnant women and elderly individuals) to promote early diagnosis and reduce morbidity and mortality [10,11]. The diagnostic accuracy of thyroid dysfunction is mainly affected by the validity of the serum TSH reference interval (RI). The accurate definition of an RI is extremely important in laboratories, but the use of reference values still remains unsatisfactory [12,13]. The TSH RI was reported to be influenced by age, coexistent acute or chronic illness, type of assay used, iodine status, and ethnicity [14]. The United States National Academy of Clinical Biochemistry (NACB) proposed the criteria for the establishment of new TSH RI, including individuals with no detectable thyroid autoantibodies, thyroid peroxidase antibodies (TPOAb), or thyroglobulin antibodies (TgAb); individuals with no personal or family history of thyroid dysfunction; individuals with no visible or palpable goiter; and individuals who did not receive any medications except estrogen [15]. However, the kit-recommended RI was typically established by measuring the serum concentrations in an AZD8055 apparently healthy ZBTB32 populace without further characterization of the thyroid and clinical chemical or demographic data [16], [17], [18], [19], [20], [21], [22]. A number of studies to date have established normal serum TSH intervals based on reference populations according to the standard of the.