Reference Ranges for Thyroid-Stimulating Hormone and Free Thyroxine in Older Men: Results From the Health In Men Study.

In older adults, thyroid-stimulating hormone (TSH) concentrations are raised and higher free thyroxine (FT4) is associated with poorer health outcomes. As use of nonage-appropriate reference ranges could lead to suboptimal management, we aimed to define reference intervals for TSH and FT4 in older men. We conducted the study on community-dwelling men aged 70-89 years. Baseline TSH and FT4 levels were assayed (Elecsys 2010, Roche Diagnostics). Conventional reference intervals for TSH and FT4 were 0.4-4.0 mIU/L and 10-23 pmol/L, respectively. Incident deaths were ascertained using data linkage. Of the 3,885 men included in the analysis, the 2.5th and 97.5th centiles for TSH and FT4 were 0.64-5.9 mIU/L and 12.1-20.6 pmol/L (0.94-1.60ng/dL), respectively. Of the 411 very healthy men defined by excellent or very good self-rated health and absence of major medical comorbidities, 2.5th to 97.5th centiles for TSH and FT4 were 0.67-4.98 mIU/L and 12.1-20.5 pmol/L (0.94-1.59ng/dL), respectively. TSH was not associated with mortality, whereas higher FT4 was associated with increased mortality. Applying intervals based on very healthy older men to the cohort as a whole led to the reclassification of 310 men (8.0%). More men were classified as being hyperthyroid or hypothyroid, or having subclinical hyperthyroidism, and fewer as having subclinical hypothyroidism. In older men, the reference interval for TSH in older men is shifted upward, whereas the reference interval for FT4 is compressed compared with the conventional reference ranges. Applying reference intervals based on healthy older men identifies a substantial number of older men as having overt thyroid disease or subclinical hyperthyroidism and reduces the number classified as having subclinical hypothyroidism.

Yeap BB ，Manning L ，Chubb SA ，Hankey GJ ，Golledge J ，Almeida OP ，Flicker L ... -  《-》

Higher free thyroxine levels are associated with all-cause mortality in euthyroid older men: the Health In Men Study.

Yeap BB ，Alfonso H ，Hankey GJ ，Flicker L ，Golledge J ，Norman PE ，Chubb SA ... -  《-》

Reference intervals for thyroid-stimulating hormone (TSH) and free thyroxine (FT4) in infants' day 14-30 of life and a comparison with other studies.

Wong JSL ，Selveindran NM ，Mohamed RZ ，Zain FM ，Anas SS ，Hong JYH ... -  《-》

Changes in thyroid function and evolution of subclinical thyroid disease in older men.

Tan SY ，Chubb SAP ，Flicker L ，Almeida OP ，Golledge J ，Hankey GJ ，Yeap BB ... -  《-》

Reference ranges of serum TSH, FT4 and thyroid autoantibodies in the Thai population: the national health examination survey.

Data on reference intervals of thyroid functions in Southeast Asia are limited. The aim of this study was to provide reference ranges of thyroid functions and thyroid autoantibodies in Thais. Serum samples from 2545 apparently healthy non-pregnant subjects, aged ≥14 years, from the fourth Thai National Health Examination Survey were measured for TSH, FT4, antithyroperoxidase (TPO Ab), antithyroglobulin (Tg Ab) and antithyrotrophin receptor antibodies (TRAb). A reference population was selected from the disease-free population by excluding those who had thyroid autoantibodies and TSH > 20 mIU/l. For the total population, median TSH and FT4 levels were 1·94 mIU/l and 1·35 ng/dl, respectively. TSH was higher and FT4 was lower in females than in males. Based on National Academy of Clinical Biochemistry criteria, the reference intervals (2·5th-97·5th percentile) were: TSH, 0·34-5·11 mIU/l; FT4, 0·98-1·79 ng/dl; TPO Ab, 5-84·88 IU/ml; Tg Ab, 10-118·2 IU/ml; and TRAb, 0·3-1·24 IU/l. With the new reference ranges, hypothyroidism was found in 4·16% of the total population (0·78% overt and 3·38% subclinical hypothyroidism) and hyperthyroidism was found in 3·18% (0·94% overt and 2·24% subclinical hyperthyroidism). Positive TPO Ab, Tg Ab and TRAb were found in 8·96%, 12·26% and 5·93%, respectively. The upper normal limit of TSH tended to increase with age, particularly for those aged 80 years and older. The reference interval for TSH needs to be derived from each specific population. Slightly elevated TSH concentrations in the elderly could be considered acceptable, with no need for thyroxine treatment.

Sriphrapradang C ，Pavarangkoon S ，Jongjaroenprasert W ，Chailurkit LO ，Ongphiphadhanakul B ，Aekplakorn W ... -  《-》