Table 1 Reference data used for age-specific prevalence estimates (%) for degenerative features of the spinal column (Brinjikji et al. [3]) and paravertebral muscle fat (%; ± standard deviation; Crawford et al. [11] and Valentin et al. [12]) according to age. Sample sizes are in parentheses

Brinjikji et al. 2015 [3]

Imaging Finding

20

30

40

50

n

Disk degeneration

37 % (273)

52 % (604)

68 % (415)

80 % (311)

(1603)

Disk signal loss

17 % (46)

33 % (142)

54 % (352)

73 % (73)

(613)

Disk height loss

24 % (15)

34 % (163)

45 % (186)

56 % (208)

(572)

Disk bulge

30 % (55)

40 % (101)

50 % (151)

60 % (123)

(430)

Disk protrusion

29 % (87)

31 % (468)

33 % (490)

36 % (363)

(1408)

Annular fissure

19 % (167)

20 % (350)

22 % (426)

23 % (53)

(996)

Facet degeneration

4 % (0), (100)^a

9 % (0), (100)^a

18 % (596)

32 % (53)

(849)

Spondylolisthesis

3 % (0), (100)^a

5 % (0), (100)^a

8 % (31)

14 % (53)

(284)

Crawford et al. 2015 [11]

Paravertebral muscles

20–29

30–39

40–49

50–60

MF + ES

12.4 ± 3.7(20)

15.9 ± 5.0(20)

15.7 ± 4.5 (20)

18.1 ± 7.8 (20)

(80)

Multifidus

16.3 ± 5.3 (20)

20.8 ± 6.4 (20)

21.6 ± 6.1 (20)

24.1 ± 8.7 (20)

(80)

Erector spinae

10.1 ± 4.7 (20)

12.9 ± 4.3 (20)

12.4 ± 3.4 (20)

14.7 ± 7.3 (20)

(80)

Valentin et al. 2015 [12]

Paravertebral muscles

18–25

45–60

Psoas

35.7 ± 2.0 (12)

37.1 ± 1.5 (12)

(24)

MF + ES

40.2 ± 3.0 (12)

42.8 ± 2.9 (12)

(24)

Multifidus

40.7 ± 3.4 (12)

43.9 ± 3.7 (12)

(24)

Erector spinae

39.6 ± 2.8 (12)

41.8 ± 2.3 (12)

(24)