Skip to main content

Table 1 Description of the cohort, stratified by gender

From: Body mass index, occupational activity, and leisure-time physical activity: an exploration of risk factors and modifiers for knee osteoarthritis in the 1946 British birth cohort

  Total Men Women  
  Mean (SD) N Mean (SD) N Mean (SD) N p-valuea
Body mass index (kg/m2) at 36y 24.1 (3.7) 2646 24.8 (3.2) 1289 23.5 (3.9) 1357 <0.001
Body mass index (kg/m2) at 43y 25.4 (4.2) 2745 25.7 (3.5) 1336 25.2 (4.7) 1409 0.001
Body mass index (kg/m2) at 53y 27.4 (4.8) 2917 27.4 (4.0) 1438 27.4 (5.5) 1479 0.812
  % N % N % N p-value a
Knee osteoarthritis clinical observation at 53y        
 Yes 10.2 302 7.5 109 12.8 193 <0.001
Disabling/life-threatening health conditions at 53y 11.9 353 11.6 169 12.2 184 0.604
 1 or more        
Family history of arthritis        
 Yes 39.3 1099 35.5 486 42.9 613 <0.001
History of knee injury        
 Yes 22.8 673 27.5 399 18.2 274 <0.001
Education at 26y        
 Degree or higher 9.9 277 14.8 203 5.2 74  
 GCE ‘A’ level, Burnham B or A2 25.6 714 28.0 384 23.3 330  
 GCE ‘O’ level or Burnham C 20.1 561 14.6 200 25.5 361  
 Sub GCE or vocational course 7.5 208 5.9 82 8.9 126  
 No qualifications 36.9 1031 36.7 504 37.2 527 <0.001
Income at 53 y        
>£50,000 8.4 234 9.7 137 7.0 97  
 £25,000-£49,999 26.1 732 27.7 391 24.5 341  
<£24,999 65.5 1835 62.6 882 68.5 953 0.002
  1. a p- values for gender comparison by means of t-test & chi square.