Table 4 The associations of F/M with thyroid hormone sensitivity in age subgroup

Age < 65 years

model I

One-line effect

 − 0.03 (− 0.07, 0.00) 0.0523

0.54 (0.28, 0.81) < 0.0001

8.27 (0.20, 16.33) 0.0448

0.55 (0.18, 0.91) 0.0031

model II

inflection point (k)

0.21

0.68

0.26

0.26

 < K segment effect 1

0.05 (− 0.15, 0.26) 0.6194

0.63 (0.32, 0.93) < 0.0001

 − 9.48 (− 39.99, 21.03) 0.5427

 − 0.13 (− 1.49, 1.24) 0.8545

 > K segment effect 2

 − 0.04 (− 0.07, − 0.00) 0.0351

0.19 (− 0.53, 0.90) 0.6096

10.55 (1.65, 19.46) 0.0205

0.63 (0.23, 1.03) 0.0019

Effect difference

 − 0.09 (− 0.30, 0.12) 0.4094

 − 0.44 (− 1.25, 0.37) 0.2870

20.03 (− 13.19, 53.25) 0.2376

0.76 (− 0.73, 2.24) 0.3164

The predicted value of the equation at the inflection point

0.35 (0.34, 0.35)

0.02 (− 0.04, 0.07)

21.06 (19.64, 22.47)

2.15 (2.09, 2.22)

Log-likelihood ratio test

0.406

0.284

0.234

0.313

Age ≥ 65 years

model I

One-line effect

0.01 (− 0.12, 0.14) 0.8632

0.18 (− 0.98, 1.34) 0.7593

26.81 (− 12.41, 66.03) 0.1855

0.85 (− 0.68, 2.39) 0.2819

model II

inflection point (k)

0.22

0.41

0.69

0.76

 < K segment effect 1

0.25 (− 0.35, 0.86) 0.4113

0.72 (− 0.93, 2.37) 0.3938

20.72 (− 22.61, 64.06) 0.3526

1.15 (− 0.52, 2.82) 0.1842

 > K segment effect 2

 − 0.01 (− 0.14, 0.13) 0.9240

 − 0.14 (− 1.49, 1.22) 0.8429

49.82 (− 28.82, 128.46) 0.2194

 − 0.99 (− 5.33, 3.35) 0.6574

Effect difference

 − 0.26 (− 0.89, 0.37) 0.4216

 − 0.86 (− 2.72, 1.00) 0.3687

29.10 (− 56.96, 115.16) 0.5102

 − 2.13 (− 6.85, 2.58) 0.3785

The predicted value of the equation at the inflection point

0.32 (0.30, 0.34)

0.10 (− 0.05, 0.25)

24.86 (18.20, 31.53)

2.37 (2.07, 2.66)

Log-likelihood ratio test

0.382

0.328

0.473

0.338