Reference Intervals for Thyroid-Associated Hormones and the Prevalence of Thyroid Diseases in the Chinese Population

Abstract

Background Thyroid diseases are highly prevalent worldwide, but their diagnosis remains a challenge. We established reference intervals (RIs) for thyroid-associated hormones and evaluated the prevalence of thyroid diseases in China. Methods After excluding outliers based on the results of ultrasound screening, thyroid antibody tests, and the Tukey method, the medical records of 20,303 euthyroid adults, who visited the Department of Health Care at Peking Union Medical College Hospital from January 2014 to December 2018, were analyzed. Thyroid-associated hormones were measured by the Siemens Advia Centaur XP analyzer. The RIs for thyroid-associated hormones were calculated according to the CLSI C28-A3 guidelines, and were compared with the RIs provided by Siemens. The prevalence of thyroid diseases over the five years was evaluated and compared using the chi-square test. Results The RIs for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total thyroxine (TT4), and total triiodothyronine (TT3) were 0.71–4.92 mIU/L, 12.2–20.1 pmol/L, 3.9–6.0 pmol/L, 65.6–135.1 nmol/L, and 1.2–2.2 nmol/L, respectively. The RIs of all hormones except TT4 differed significantly between males and females. The RIs of TSH increased with increasing age. The prevalence of overt hypothyroidism, overt hyperthyroidism, subclinical hypothyroidism, and subclinical hyperthyroidism was 0.5% and 0.8%, 0.2% and 0.6%, 3.8% and 6.1%, and 3.3% and 4.7% in males and females, respectively, which differed from those provided by Siemens. Conclusions Sex-specific RIs were established for thyroid-associated hormones, and the prevalence of thyroid diseases was determined in the Chinese population.

Establishment of Reference Intervals for Thyroid-Associated Hormones Using refineR Algorithm in Chinese Population at High-Altitude Areas

“…Difference in the upper limits may be explained by the age composition of the population living at different altitudes in China, as in the case of the three regions of Tibet, where the proportion of people aged >65 years was only approximately 5% (32). Obvious discrepancies were observed for TSH, FT3, and FT4 levels between males and females, although the effect of sex on TSH level was not as remarkable as those on FT3 or FT4, which was consistent with previous studies (14,27,33,34). Thus, sexspecific RIs for FT4 and FT3, but not for TSH, were proposed in our study and results showed that both the upper and lower limits of RIs for FT3 and FT4 were higher in males than in females, which can be interpreted by the potential effect of sex hormones on the HPT axis (10,35).…”

Age- and sex-specific reference intervals for thyroid hormones in a Chinese pediatrics: a prospective observational study of 1,279 healthy children

“…FT3 significantly increased upon puberty and showed a significant sex-specific difference at which age, while FT4 remained constant throughout puberty (10). In China, the sex/geographic/assay-specific and gestation-specific RIs of thyroid hormones have been established in adult populations (22)(23)(24)(25), emphasizing the need for assay-specific RIs of thyroid hormones in Chinese pediatric populations to avoid false positive or negative results.…”

“…The sex-specific and gestation-specific RIs of thyroid hormones have been established in Chinese adult populations (22)(23)(24)(25). Therefore, the present study aimed to evaluate the distribution of thyroid hormones and to establish age-and sex-specific RIs for a Chinese pediatric population.…”

Establishment of Reference Intervals of Ten Commonly Used Clinical Chemistry Analytes: A Real-World Study in China

“…Previous studies rarely used large sample of data of Chinese population to establish RIs. Besides, instead of developing RIs for a broad spectrum of clinical chemistry analytes, previous publications usually focused on a single analyte or specific health issue, such as thyroid-associated biomarkers or myocardial enzyme analytes [16,17]. Hence, our study could fill these gaps to some extent.…”