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Table 1 Participant characteristics and prevalence of MRI findings in LBP and no-LBP groups including test for group difference. The MRI findings are based on the worst score at any lumbar level (L1-L5)

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

41 Years
CharacteristicsTotal
n = 412
LBP Year
n = 284 (68.93%)
No LBP Year
n = 128 (31.07%)
P-Value
Sex
 Men n (%)199 (48.30)134 (47.18)65 (50.78)0.499
 Women n (%)213 (51.70)150 (52.82)63 (49.22) 
BMI Mean (SD)25.05 (4.25)25.24 (4.28)24.63 (4.19)0.176
MRI Findings
 Signal Intensity (worst lumbar level)
  Grade 0 n (%)4 (0.97)3 (1.06)1 (0.78) 
  Grade 1 n (%)51 (12.38)28 (9.86)23 (17.97) 
  Grade 2 n (%)171 (41.50)105 (36.97)66 (51.56) 
  Grade 3 n (%)186 (45.15)148 (52.11)38 (29.69)0.000*a
 Disc Height (worst lumbar level)
  Grade 0 n (%)90 (21.84)56 (19.72)34 (26.56) 
  Grade 1 n (%)103 (25.00)57 (20.07)46 (35.94) 
  Grade 2 n (%)207 (50.24)161 (56.69)46 (35.94) 
  Grade 3 n (%)12 (2.91)10 (3.52)2 (1.56)0.000*a
45 Years
CharacteristicsTotal
n = 348
LBP Year
n = 238 (68.39%)
No LBP Year
n = 110 (31.61%)
P-Value
Sex
 Men n (%)161 (46.26)109 (45.80)52 (47.27)0.798
 Women n (%)187 (53.74)129 (54.20)58 (52.73) 
BMI Mean (SD)25.16 (4.05)25.43 (4.23)24.57 (3.60)0.051
MRI Findings
 Signal Intensity (worst lumbar level)
  Grade 0 n (%)000 
  Grade 1 n (%)52 (15.12)28 (11.81)24 (22.43) 
  Grade 2 n (%)121 (35.17)89 (37.55)32 (29.91) 
  Grade 3 n (%)171 (49.71)120 (50.63)51 (47.66)0.033*b
 Disc Height (worst lumbar level)
  Grade 0 n (%)107 (31.10)73 (30.80)34 (31.78) 
  Grade 1 n (%)69 (20.06)48 (20.25)21 (19.63) 
  Grade 2 n (%)154 (44.77)109 (45.99)45 (42.06) 
  Grade 3 n (%)14 (4.07)7 (2.95)7 (6.54)0.458a
49 Years
CharacteristicsTotal
n = 293
LBP Year
n = 204 (69.62%)
No LBP Year
n = 89 (30.38%)
P-Value
Sex
 Men n (%)136 (46.42)85 (41.67)51 (57.30)0.014*
 Women n (%)157 (53.58)119 (58.33)38 (42.70) 
BMI Mean (SD)27.28 (17.84)28.19 (21.21)25.21 (3.44)0.054
MRI Findings
 Signal Intensity (worst lumbar level)
  Grade 0 n (%)000 
  Grade 1 n (%)31 (10.88)15 (7.54)16 (18.60) 
  Grade 2 n (%)154 (54.04)109 (54.77)45 (52.33) 
  Grade 3 n (%)100 (35.09)75 (37.69)25 (29.07)0.017*b
 Disc Height (worst lumbar level)
  Grade 0 n (%)44 (15.44)23 (11.56)21 (24.42) 
  Grade 1 n (%)52 (18.25)36 (18.09)16 (18.60) 
  Grade 2 n (%)160 (56.14)120 (60.30)40 (46.51) 
  Grade 3 n (%)29 (10.18)20 (10.05)9 (10.47)0.037*b
  1. * = Statistically significant difference between LBP and no-LBP groups (P-value < 0.05)
  2. a = P-value was obtained using Fischer’s exact test
  3. b = P-value was obtained using Pearson’s chi2 test