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. Author manuscript; available in PMC: 2011 Nov 1.
Published in final edited form as: Osteoarthritis Cartilage. 2010 Sep 17;18(11):1386–1392. doi: 10.1016/j.joca.2010.08.015

Table 1.

Demographics of case and control groups at baseline in the present study

Case knees Control knees p-value$
Incident knee pain
 N 157 336
 Age, mean (SD) 62.8 (8.2) 61.5 (8.1) 0.095
 Women, no. (%) 108 (69) 200 (60) 0.048*
 White, no. (%) 137 (87) 292 (86) 0.91
 BMI, mean (SD) 29.7 (4.6) 29.7 (4.5) 0.99
 ROA (K-L grade≥2), no. (%) 64 (41) 75 (22) <.0001*
 BML (grade≥1), (%) 117 (75) 225 (67) 0.090
 Cartilage loss (grade≥2), (%) 141 (90) 271 (81) 0.011*
 Meniscal damage (grade≥1), (%) 68 (43) 99 (30) 0.0025*
 Synovitis (grade≥1), (%) 107 (68) 213 (63) 0.30
 Effusion (grade≥1), (%) 63 (40) 112 (33) 0.14
Malalignment**
  Varus (<179°), no. (%) 71 (45) 138 (41) 0.028*
  Neutral (179–181°), no. (%) 45 (29) 139 (41)
  Valgus (>181°), no. (%) 39 (25) 57 (17)
Incident radiographic OA
 N 149 298
 Age, mean (SD) 61.7 (7.7) 61.5 (7.7) 0.79
 Women, % 92 (62) 177 (59) 0.60
 White, % 120 (81) 258 (86) 0.11
 BMI, mean (SD) 31.0 (5.4) 28.9 (4.5) <.0001*
 BML (grade≥1), (%) 104 (70) 174 (58) 0.056
 Cartilage loss (grade≥2), (%) 144 (97) 232 (78) <.0001*
 Meniscal damage (grade≥1), (%) 71 (48) 55 (18) <.0001*
 Synovitis (grade≥1), (%) 72 (48) 87 (29) 0.0003*
 Effusion (grade≥1), (%) 99 (66) 122 (41) <.0001*
Malalignment
  Varus (<179°), no. (%) 77 (52) 129 (43) 0.059
  Neutral(179–181°), no. (%) 44 (30) 118 (40)
  Valgus (>181°), no. (%) 25 (17) 51 (17)

Abbreviations: N = total number of knees in case and control groups; SD = standard deviation; BMI = body mass index; ROA = radiographic osteoarthritis; BML = bone marrow lesion; K-L grade = Kellgren-Lawrence grade.

*

denotes statistically significant differences (p<0.05).

scored using the Whole Organ Magnetic Resonance Imaging Score (scale 0–3 for BML and synovitis and effusion; scale 0–6 for cartiage; and scale 0–4 for meniscus.)

$

calculated by chi-square test or 2-sample t-test, as appropriate.