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Table 1 Demographic data (n = 4638)

From: Low back pain precedes the development of new knee pain in the elderly population; a novel predictive score from a longitudinal cohort study

Variables With new knee pain (n = 1262) Without new knee pain (n = 3376)
Age (year) 63.6 ± 6.5 [50–75] 62.0 ± 6.3 [50–75]
Sex
 Male 411 (32.6) 1221 (36.2)
 Female 851 (67.4) 2155 (63.8)
BMI 23.1 ± 3.1 [14.3–36.1] 22.3 ± 2.8 [13.6–37.8]
Weight change, No (%)
 Within 3 kg 286 (22.7) 965 (28.6)
 3〜10 kg increase 473 (37.5) 1190 (35.3)
 10 kg < increase 277 (22.0) 592 (17.5)
 3〜10 kg decrease 226 (17.9) 629 (18.6)
 3 kg < decrease 0 (0) 0 (0)
Smoking
 Current smoker 130 (10.3) 361(10.7)
 Quitted 263 (20.8) 728 (21.6)
 Never smoker 869 (68.9) 2287 (67.7)
Alcohol
 Current drinker 688 (54.5) 2034 (60.1)
 Quitted 31 (2.5) 46 (1.4)
 Never drinker 543 (43.0) 1296 (38.4)
Alcohol consumption (unit/day)
 < 1 unit 420 (61.0) 1200 (59.3)
 1 ≤ consumption < 2 198 (28.7) 591 (29.2)
 2 ≤ consumption < 3 62 (9.0) 182 (9.0)
 3 ≤ consumption 9 (1.3) 49 (2.5)
Activity
 Sedentary 76 (6.0) 237 (7.0)
 Moderately active 883 (70.0) 2341 (69.3)
 Active 303 (24.0) 798 (23.7)
Mental health (points) 18.5 ± 3.4 [6–25] 19.1 ± 3.3 [5–25]
Low back pain (points) 0, 0–1 [0–20] 0, 0–2 [0–20]
ABI 1.09 ± 0.08 [0.58–1.31] 1.08 ± 0.07 [0.51–1.39]
hsCRP (mg/dl) 1019.2 ± 3073.5 [50–52,700] 897.1 ± 3338.4 [50–1,260,000]
NTX (nmolBCE/nmolCr) 40.5 ± 21.0 [7–154] 40.2 ± 20.2 [5–196]
CTX (μg/nmolCr) 224.9 ± 139.1 [14–1005] 226.4 ± 131.0 [13–1103]
  1. Data for continuous variables are expressed as mean ± SD [minimum–maximum] except for low back pain (median, inter-quartile range [minimum–maximum]), and data for categorical variables are expressed as numbers and percentages
  2. BMI body mass index, ABI ankle-brachial pressure index, hsCRP high-sensitivity C-reactive protein, NTX cross-linked N-telopeptide of type I collagen (urine), CTX cross-linked C-telopeptide of type I collagen (urine)