The Change of Thyroid Stimulating Hormone Values of Healthy Subjects According toTemperature and Aging

Abstract

Abstract Objective: We conducted a study to investigate the normal range for TSH and within-individual variations of TSH according to temperat䴸re and aging. Patients and Methods: We enrolled patients who underwent periodic medical examinations five times over a six year period (2007.8~2013.6). Anthropometric data and thyroid ultrasonography were evaluated, and serum TSH, T3, and T4 were assayed. Results: Subjects were 19-64 years old, 120 were female, and 208 were male. Reference ranges for TSH were 0.53-4.94 mlU/L in the first test, 0.49-5.61 mlU/L in the second test, 0.46-6.06 mlU/L in the third test, 0.48-5.99 mlU/L in the fourth test, and 0.52-6.3 mlU/L in the fifth test. When the TSH level was analyzed according to temperature and sex, mean TSH was higher in months in which the average monthly temperatures were below 100C in Jinju, Gyeongnam and female. The aging and low temperatures are associated with increased serum TSH concentrations in the within-individual. Conclusions: This study showed that aging is associated with increased serum TSH concentrations in the within- individual and serum TSH concentrations are different in the within-individual according to the temperature.

Keywords

• reference range for tsh
• tsh
• variation of tsh