Background: This study aims to establish reference intervals (RIs) for thyroid hormones in the elderly population and analyze their influence on the prevalence of subclinical hypothyroidism.
Methods: Thyroid hormone records of subjects who underwent routine health checkup at our hospital between 2018 and 2020 were analyzed. Thyroid stimulating hormone (TSH), total triiodothyronine, total thyroxine, free triiodothyronine (FT3), and free thyroxine (FT4) levels were compared between young and elderly subjects. Thresholds of these thyroid hormones were established for elderly subjects.
Results: A total of 22,207 subjects were included. Of them, 2,254 (10.15%) were aged ≥ 65 years. Elderly subjects had higher TSH, and lower FT3 and FT4 levels when compared with young subjects. In the elderly group, the RIs for TSH, FT3 and FT4 were 0.55-5.14 mIU/L, 3.68-5.47 pmol/L, and 12.00-19.87 pmol/L, respectively. The age and sex specific RIs for TSH were 0.56-5.07 mIU/L for men and 0.51-5.25 mIU/L for women. With whole-group RIs and age and sex-specific RIs for elderly people, the prevalence of subclinical hypothyroidism was 9.83% and 6.29% (p < 0.001), respectively.
Conclusions: Elderly individuals had higher TSH levels than young individuals. Our study indicated that establishing specific RIs for elderly individuals is needed. This has implications for the diagnosis and management of subclinical hypothyroidism in the elderly population.
Uvod: Ova studija ima za cilj da utvrdi referentne intervale (RI) za tiroidne hormone u starijoj populaciji i analizira njihov uticaj na prevalenciju subkliničkog hipotireoze.
Metode: Analizirani su podaci o hormonima štitaste žlezde ispitanika koji su bili podvrgnuti rutinskom zdravstvenom pregledu u našoj bolnici u periodu od 2018. do 2020. godine. Tireostimulišući hormon (TSH), ukupni trijodtironin, ukupni tiroksin, slobodni trijodtironin (FT3) i nivo slobodnog tiroksina (FT4) upoređivani su između mladih i starijih ispitanika. Pragovi vrednosti ovih tiroidnih hormona su utvrđeni za starije osobe.
Rezultati: Uključeno je ukupno 22.207 ispitanika. Od njih 2.254 (10,15%) bilo je staro ≥ 65 godina. Stariji subjekti su imali veći TSH i niže nivoe FT3 i FT4 u poređenju sa mladim subjektima. U starijoj grupi, RI za TSH, FT3 i FT4 bili su 0,55-5,14 mIU/L, 3,68-5,47 pmol/L i 12,00-19,87 pmol/L, respektivno. RI za TSH bio je 0,56-5,07 mIU/L za muškarce i 0,51-5,25 mIU/L za žene. Kod RI cele grupe i RI specifičnih za uzrast i pol za starije osobe, prevalencija subkliničkog hipotireoze bila je 9,83% i 6,29% (p < 0,001), respektivno.
Zaključak: Starije osobe su imale veći nivo TSH od mladih osoba. Naša studija je pokazala da je potrebno uspostavljanje specifičnih RI za starije osobe. Ovo ima implikacije na dijagnozu i lečenje subkliničkog hipotireoze kod starije populacije.
Keywords: elderly; reference intervals; subclinical hypothyroidism; thyroid hormones.
2023 Jingxuan Fu, Yidan Wang, Yunyi Liu, Qinfei Song, Jingrong Cao, Wang Peichang, published by CEON/CEES.