Table 3.
Associations and difference in diagnostic accuracy between disc height 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, 2 and 3 is reported as p-values from chi square tests. More details are given in Additional File 5
| Disc height at 41 Years | Threshold 1: ≥ grade 1 (n = 319) (77.99%) OR (95% CI) |
Threshold 2: ≥ grade 2 (n = 218) (53.30%) OR (95% CI) |
Threshold 3: = grade 3 (n = 12) (2.93%) OR (95% CI) |
AUC comparison (p-value) |
|---|---|---|---|---|
| All participants (n = 409) | 1.44 (0.89;2.35) | 2.53 (1.64;3.90)* | 2.29 (0.49;10.63) |
AUC T1 = AUC T2: 0.004* AUC T2 = AUC T3: 0.006* AUC T1 = AUC T3: 0.760 |
| Men (n = 197) | 2.14 (1.02;4.49)* | 3.96 (2.11;7.43)* | 1.82 (0.20;16.80) |
AUC T1 = AUC T2: 0.001* AUC T2 = AUC T3: 0.000* AUC T1 = AUC T3: 0.121 |
| Women (n = 210) | 1.09 (0.55;2.14) | 1.73 (0.94;3.18) | 2.12 (0.24;18.55) |
AUC T1 = AUC T2: 0.001* AUC T2 = AUC T3: 0.004* AUC T1 = AUC T3: 0.586 |
| Upper lumbar spine (n = 409) | 1.44 (0.88;2.36) | 3.68 (1.62;8.38)* | – | AUC T1 = AUC T2: 0.097 |
| Lower lumbar spine (n = 409) | 1.49 (0.94;2.38) | 2.31 (1.49;3.57)* | 2.00 (0.42;9.42) |
AUC T1 = AUC T2: 0.019 AUC T2 = AUC T3: 0.01* AUC T1 = AUC T3: 0.519 |
| Disc height at 45 Years |
Threshold 1: ≥ grade 1 (n = 237) (69.50%) OR (95% CI) |
Threshold 2: ≥ grade 2 (n = 168) (49.27%) OR (95% CI) |
Threshold 3: = grade 3 (n = 14) (4.11%) OR (95% CI) |
AUC comparison (p-value) |
| All participants (n = 341) | 1.05 (0.64;1,74) | 0.97 (0.61;1,55) | 0.43 (0.15;1.26) |
AUC T1 = AUC T2: 0.724 AUC T2 = AUC T3: 0.296 AUC T1 = AUC T3: 0.275 |
| Men (n = 160) | 1.53 (0.73;3.21) | 1.17 (0.59;2.29) | 1.13 (0.21;6.09) |
AUC T1 = AUC T2: 0.725 AUC T2 = AUC T3: 0.954 AUC T1 = AUC T3: 0.795 |
| Women (n = 181) | 0.77 (0.39;1.55) | 0.83 (0.43;1.58) | 0.16 (0.03;0.87)* |
AUC T1 = AUC T2: 0.929 AUC T2 = AUC T3: 0.441 AUC T1 = AUC T3: 0.540 |
| Upper lumbar spine (n = 341) | 1.51 (0.86;2.64) | 1.94 (0.93;4.06) | – | AUC T1 = AUC T2: 0.735 |
| Lower lumbar spine (n = 341) | 0.99 (0.62;1.60) | 0.96 (0.60;1.54) | 0.43 (0.15;1.26) |
AUC T1 = AUC T2: 0.896 AUC T2 = AUC T3: 0.284 AUC T1 = AUC T3: 0.302 |
| Disc height at 49 Years |
Threshold 1: ≥ grade 1 (n = 238) (84.40%) OR (95% CI) |
Threshold 2: ≥ grade 2 (n = 187) (66.31%) OR (95% CI) |
Threshold 3: = grade 3 (n = 29) (10.28%) OR (95% CI) |
AUC comparison (p-value) |
| All participants (n = 282) | 2.49 (1.28;4.85)* | 1.84 (1.08;3.13)* | 0.89 (0.38;2.06) |
AUC T1 = AUC T2: 0.995 AUC T2 = AUC T3: 0.134 AUC T1 = AUC T3: 0.070 |
| Men (n = 132) | 3.22 (1.27;8.16)* | 2.20 (1.04;4.64)* | 1.73 (0.51;5.84) |
AUC T1 = AUC T2: 0.864 AUC T2 = AUC T3: 0.046* AUC T1 = AUC T3: 0.019* |
| Women (n = 150) | 1.69 (0.61;4.68) | 1.57 (0.72;3.42) | 0.44 (0.13;1.48) |
AUC T1 = AUC T2: 0.876 AUC T2 = AUC T3: 0.081 AUC T1 = AUC T3: 0.074 |
| Upper lumbar spine (n = 282) | 3.69 (2.00;6.81)* | 4.77 (2.17;10.49)* | – | AUC T1 = AUC T2: 0.448 |
| Lower lumbar spine (n = 282) | 1.74 (0.95;3.17) | 1.50 (0.89;2.52) | 0.89 (0.38;2.10) |
AUC T1 = AUC T2: 0.971 AUC T2 = AUC T3: 0.233 AUC T1 = AUC T3: 0.202 |
* = P-value < 0.05
-No participants with or without LDD at this threshold