Table 1

Characteristics of participants (n = 326)

Characteristic
Offspring (n = 163)
Controls (n = 163)
P

Values at baseline (2000–2001)



     Age (years)
45.1 ± 6.5
45.2 ± 6.5
0.87
     Height (cm)
169 ± 8
169 ± 9
0.84
     Weight (kg)
80 ± 16
75 ± 14
0.04
     BMI (kg/m2)
27.9 ± 5.1
26.2 ± 4.3
0.02
     Prevalence of knee pain (%)
47
22
<0.01a
     Lower-limb muscle strength (kg)
127 ± 49
135 ± 50
0.006
     PWC170 (W/kg)
2.94 ± 1.13
2.91 ± 0.99
0.77
Change during two-year follow-up



     Change in weight (kg)
1.2 ± 4.4
1.3 ± 5.0
0.89
     Change in BMI (kg/m2)
0.6 ± 1.5
0.7 ± 1.8
0.58
     Incidence of knee pain (%)
47
41
0.35a
     Change in lower-limb muscle strength (kg)
-8.5 ± 24.6
-10.7 ± 28.0
0.47
     Change in PWC170 (W/kg)
-0.7 ± 1.0
-0.4 ± 0.9
<0.01

Where errors are shown, results are means ± SD. BMI, body mass index; PWC170, physical work capacity at 170 beats/minute. aMcNemar tests; others are paired t tests.

Ding et al. Arthritis Research & Therapy 2006 8:R8   doi:10.1186/ar1835