Table 2.

TSH values and LT4 dosage according to age.

	18–29 (n: 188)	30–39 (n: 320)	40–49 (n: 455)	50–59 (n: 478)	60–69 (n: 248)	70–79 (n: 54)	80–89 (n: 12)	P
TSH (mIU/mL)	5.5 ± 2.8	5.2 ± 3.5	5.1 ± 3	3.9 ± 0.4	3.03 ± 2	6.2 ± 2.1	4.8 ± 5.2	0.04
Duration of treatment (yrs)	5 ± 3.7	4.6 ± 4	5.7 ± 4	6.2 ± 5.6	7.3 ± 6	8.2 ± 5.2	13.7 ± 9	0.04
Daily dose (µg/day)	95.4 ± 49	95.7 ± 45	104 ± 56	91.3 ± 43	87.9 ± 39	94.9 ± 42	73.8 ± 35	0.001
Daily LT4 dosage (µg/kg)	1.44 ± 0.8	1.51 ± 0.6	1.34 ± 0.6	1.72 ± 0.3	1.59 ± 0.2	1.24 ± 0.5	1.04 ± 0.4	0.001

Yrs, years; LT4, levothyroxine.