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Table 3 Bone parameters at the radius, tibia, and third metacarpal bone in RA patients and controls (means ± sd), P-values of two-sided Mann-Whitney tests (significant values are in bold), and difference between mean values of RA and control group

From: Reduced trabecular bone mineral density and cortical thickness accompanied by increased outer bone circumference in metacarpal bone of rheumatoid arthritis patients: a cross-sectional study

   Group RA (n = 50) Ref (n = 100) Mann-Whitney test P-value Relative difference [%]
Bone Site Parameter Mean SD Mean SD   
Radius 4% BMC (g/cm) 1.03 0.23 1.09 0.17 0.087 -5.5
   Total CSA (mm2) 339.3 55.3 338.4 48.2 0.599 0.3
   Total BMD (mg/cm3) 305.3 58.2 325.5 53.1 0.076 -6.2
   Trab. BMD (mg/cm3) 151.6 47.3 186.1 38.4 0.000 -18.5
  66% BMC (g/cm) 0.89 0.21 0.98 0.16 0.009 -9.2
   Total CSA (mm2) 139.4 26.1 132.6 20.7 0.110 5.1
   Cort. CSA (mm2) 63.3 19.6 71.8 13.3 0.017 -11.8
   Cort. BMD (mg/cm3) 1,094.0 78.7 1137.6 57.3 0.000 -3.8
   Cort. Thickness (mm) 1.80 0.59 2.14 0.45 0.001 -15.9
Tibia 4% BMC (g/cm) 2.76 0.60 3.02 0.43 0.002 -8.6
   Total CSA (mm2) 1,087.6 161.2 1071.7 126.9 0.251 1.5
   Total BMD (mg/cm3) 255.0 47.7 284.6 43.7 0.000 -10.4
   Trab. BMD (mg/cm3) 192.5 43.5 222.9 37.3 0.000 -13.6
  66% BMC (g/cm) 3.54 0.54 3.72 0.43 0.085 -4.8
   Total CSA (mm2) 549.9 81.4 548.3 67.6 0.956 0.3
   Cort. CSA [mm2) 266.4 43.9 282.6 33.4 0.048 -5.7
   Cort. BMD (mg/cm3) 1,117.0 54.8 1130.6 36.6 0.152 -1.2
   Cort. Thickness (mm) 3.78 0.65 4.05 0.52 0.029 -6.7
MCP3 4% BMC (mg/mm) 40.48 9.96 43.70 7.18 0.031 -7.4
   Total CSA (mm2) 124.8 19.6 124.2 13.0 0.751 0.5
   Total BMD (mg/cm3) 321.6 66.0 351.8 44.4 0.001 -8.6
   Trab. BMD (mg/cm3) 266.0 80.5 303.2 44.9 0.001 -12.3
  30% BMC (mg/mm) 43.68 11.34 47.07 6.16 0.130 -7.2
   Total CSA (mm2) 76.10 13.60 71.26 11.52 0.015 6.8
   Cort. CSA (mm2) 31.59 8.49 34.66 4.22 0.088 -8.9
   Cort. BMD (mg/cm3) 1,100.1 87.5 1146.2 57.7 0.005 -4.0
   Cort. Thickness (mm) 1.19 0.36 1.38 0.23 0.005 -13.8
  50% BMC (mg/mm) 44.97 11.39 48.25 6.22 0.102 -6.8
   Total CSA (mm2) 59.69 8.15 56.66 6.13 0.019 5.3
   Cort. CSA (mm2) 33.04 8.56 36.06 4.70 0.043 - 8.4
   Cort. BMD (mg/cm3) 1,153.0 76.5 1,189.9 44.7 0.008 -3.1
   Cort. Thickness (mm) 1.48 0.45 1.71 0.28 0.001 -13.5
   relative cortical area 0.56 0.14 0.64 0.08 0.001 -12.5
  1. P-values are rounded to three decimal places, values of 0.000 are equivalent to P < 0.0005. BMC stands for bone mineral content per mm of slice thickness, CSA for cross-sectional area, BMD for volumetric bone mineral density, trab for trabecular and cort for cortical.