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Table 2 Associations and difference in diagnostic accuracy between disc signal intensity and ‘LBP year’ at different thresholds and ages. Associations are expressed as odds ratios (OR) with 95% confidence intervals (95% CI) obtained from logistic regression analyses adjusted for body mass index. The probability of no difference in Area Under Curves (AUC) between Thresholds 1 and 2 is reported as p-values from chi square tests. More details are given in Additional File 4

From: An exploratory study of different definitions and thresholds for lumbar disc degeneration assessed by MRI and their associations with low back pain using data from a cohort study of a general population

Disc signal intensity at 41 Years

Threshold 2: ≥ grade 2

(n = 356) (87.04%)

OR (95% CI)

Threshold 3: = grade 3

(n = 185) (45.23%)

OR (95% CI)

AUC comparison (p-value)

All participants (n = 409)

2.02 (1.12;3.64)*

2.57 (1.65;4.02)*

AUC T2 = AUC T3: 0.020*

 Men (n = 197)

2.88 (1.20;6.90)*

2.52 (1.35;4.72)*

AUC T2 = AUC T3: 0.017*

 Women (n = 210)

1.63 (0.70;3.76)

2.90 (1.50;5.60)*

AUC T2 = AUC T3: 0.016*

 Upper lumbar spine (n = 409)

1.16 (0.76;1.77)

2.27 (0.91;5.62)

AUC T2 = AUC T3: 0.240

 Lower lumbar spine (n = 409)

1.91 (1.16;3.16)*

2.55 (1.61;4.05)*

AUC T2 = AUC T3: 0.111

Disc signal intensity at 45 Years

Threshold 2: ≥ grade 2

(n = 290) (85.04%)

OR (95% CI)

Threshold 3: = grade 3

(n = 170) (49.85%)

OR (95% CI)

AUC comparison (p-value)

All participants (n = 341)

2.17 (1.18;4.00)*

1.10 (0.69;1.75)

AUC T2 = AUC T3: 0.123

 Men (n = 160)

2.25 (0.92;5.47)

1.47 (0.75;2.90)

AUC T2 = AUC T3: 0.134

 Women (n = 181)

2.11 (0.90;4.92)

0.85 (0.45;1.61)

AUC T2 = AUC T3: 0.267

 Upper lumbar spine (n = 341)

1.34 (0.84;2.14)

1.48 (0.72;3.06)

AUC T2 = AUC T3: 0.767

 Lower lumbar spine (n = 341)

1.57 (0.91;2.74)

0.98 (0.61;1.55)

AUC T2 = AUC T3: 0.589

Disc signal intensity at 49 Years

Threshold 2: ≥ grade 2

(n = 251) (89.01%)

OR (95% CI)

Threshold 3: = grade 3

(n = 100) (35.46%)

OR (95% CI)

AUC comparison (p-value)

All participants (n = 282)

2.65 (1.23;5.67)*

1.49 (0.86;2.59)

AUC T2 = AUC T3: 0.859

 Men (n = 132)

5.49 (1.63;18.52)*

2.30 (1.05;5.06)*

AUC T2 = AUC T3: 0.825

 Women (n = 150)

1.35 (0.43;4.25)

0.98 (0.44;2.16)

AUC T2 = AUC T3: 0.01*

 Upper lumbar spine (n = 282)

2.08 (1.21;3.58)*

5.08 (1.16;22.21)*

AUC T2 = AUC T3: 0.247

 Lower lumbar spine (n = 282)

2.23 (1.15;4.30)*

1.29 (0.74;2.26)

AUC T2 = AUC T3: 0.324

  1. Note: The results for threshold ≥1 were underpowered and are therefore not presented in the Table
  2. * P-value < 0.05