Table 1 

Sample characteristics 

Total sample (n = 2,092)* 
Subset with all radiographs (n = 1,373) 

Mean (SD) or n (%) 
Mean (SD) or % 



Age (years) 
65.1 (10.9) 
67.3 (9.7) 
BMI (kg/m^{2}) 
31.3 (7.1) 
30.8 (6.4) 
Male 
695 (33.2) 
472 (34.4) 
African American 
709 (33.9) 
438 (31.9) 
DIP OA^{†} 
902 (43.2) 
637 (46.4) 
PIP OA 
595 (28.5) 
419 (30.5) 
MCP OA 
195 (9.4) 
132 (9.6) 
CMC1 OA 
577 (27.7) 
416 (30.3) 
TFJ OA 
822 (39.8) 
554 (40.4) 
PFJ Ost > = 2 
174 (11.8) 
142 (10.3) 
Hip OA 
643 (33.8) 
475 (34.9)^{§} 
LS OA^{‡} 
1,138 (59.2) 
836 (60.9) 


*For total sample (at least one radiograph, see Figure), For LS OA n = 1,923; 2,068 for TFJ OA; 1,901 for Hip OA; 1,481 for PFJ Ost; 2,088 for DIP and PIP OA; 2,086 for MCP and CMC OA ^{†}Where OA is defined as KL grade > = 2 at any DIP, PIP, CMC, MCP, TFJ, or hip joint ^{‡}Defined as having at least one lumbar level (L1/2 to L5/S1) with both ost and DN OARSI grade > = 1 ^{§}Hip OA n = 1,360 BMI, body mass index; CMC, carpometacarpal joint; DIP, distal interphalangeal joint; LS, lumbosacral spine; MCP, metacarpophalangeal joint; OA, osteoarthritis; OST, osteophytes; PFJ, patellofemoral joint; PIP, proximal interphalangeal joint; SD, standard deviation; TFJ, tibiofemoral joint. 

Nelson et al. Arthritis Research & Therapy 2011 13:R176 doi:10.1186/ar3501 