Table 1 Population characteristics of biochemically euthyroid individuals in included cohorts (n = 9432)

Age in years (median (IQR))

23.0 (21.0–26.0)

59.8 (55.1–65.5)

65.7 (61.8–70.4)

43.0 (30.0–53.0)

75.4 (72.9–78.3)

68.9 (65.2–73.3)

Women

200 (55.2)

181 (78.7)

202 (48.2)

1594 (64.6)

2195 (48.6)

773 (53.6)

Current smoker

47 (13.1)^a

38 (16.5)

51 (12.2)^c

984 (39.9)

1231 (27.3)^g

204 (14.2)^h

BMI (median (IQR))

22.3 (20.8–24.2)^b

26.0 (24.0–29.0)

26.3 (24.2–28.6)^d

24.6 (22.0–28.0)^f

26.2 (23.8–28.9)^g

26.4 (24.2–29.0)

TSH (median (IQR))

2.09 (1.59–2.79)

1.76 (1.27–2.34)

2.13 (1.54–2.89)

2.07 (1.47–2.80)

1.73 (1.22–2.44)

1.76 (1.27–2.51)

fT4 (mean (SD))

16.4 (2.1)

15.8 (1.8)

15.6 (1.9)

15.6 (2.0)

15.6 (1.9)

15.7 (1.8)

History of diabetes mellitus

0 (0.0)

3 (1.3)

20 (6.0)^e

103 (4.2)

471 (10.4)

149 (10.4)ⁱ

Lipid-lowering medication use

0 (0.0)

8 (3.5)

55 (16.6)^e

184 (7.5)

2248 (49.8)

199 (14.7)^j

History of thyroid disease

0 (0.0)

N.A.

N.A.

62 (2.5)

N.A.

111 (7.7)

Thyroid medication use

0 (0.0)

3 (1.3)

7 (2.1)^e

34 (1.4)

113 (2.5)

28 (1.9)

Medication use influencing the thyroid gland

0 (0.0)

N.A.

1 (0.3)^e

3 (0.1)

12 (0.3)

N.A.