Table 4

Adjusted associations of BMI and activity (occupational/ leisure) at 36, 43, and 53 years with kOA in women
36 years 43 years 53 years
OR p-value OR p-value OR p-value
Manual occupation 1.85 (1.06, 3.24) 0.031 1.09 (0.66, 1.82) 0.734 1.87 (1.22, 2.86) 0.004
Non-manual occupation Referent Referent Referent
BMI (per z-score) 1.49 (1.16, 1.91) 0.002 1.73 (1.39, 2.15) <0.001 1.92 (1.59, 2.33) <0.001
 p-value for test of interaction 0.691 0.570 0.203
Lifting unlikely 0.89 (0.51, 1.55) 0.681 1.10 (0.67, 1.81) 0.710 0.71 (0.42, 1.19) 0.317
Lifting somewhat likely Referent Referent Referent
Lifting highly likely 0.73 (0.32, 1.66) 0.449 1.09 (0.55, 2.18) 0.070 1.02 (0.51, 2.07) 0.590
BMI (per z-score) 1.80 (1.47, 2.21) <0.001 1.85 (1.52, 2.25) <0.001 1.73 (1.49, 2.24) <0.001
 p-value for test of interaction 0.344 0.580 0.808
Kneeling unlikely 0.74 (0.49, 1.11) 0.143 0.79 (0.52, 1.18) 0.248 0.93 (0.58, 1.51) 0.776
Kneeling somewhat likely Referent Referent Referent
Kneeling highly likely 0.91 (0.45, 1.85) 0.793 0.80 (0.41, 1.59) 0.530 1.23 (0.58, 2.61) 0.582
BMI (per z-score) 1.78 (1.45, 2.18) <0.001 1.83 (1.50, 2.22) <0.001 1.91 (1.29, 2.83) <0.001
 p-value for test of interaction 0.295 0.780 0.405
Sitting unlikely 1.15 (0.72, 1.84) 0.549 0.76 (0.47, 1.24) 0.276 1.29 (0.77, 2.16) 0.343
Sitting somewhat likely Referent Referent Referent
Sitting highly likely 0.56 (0.33, 0.94) 0.029 0.57 (0.36, 0.89) 0.013 0.89 (0.56, 1.43) 0.653
BMI (per z-score) 1.77 (1.45, 2.18) <0.001 1.80 (1.48, 2.19) <0.001 1.48 (1.41, 2.22) <0.001
 p-value for test of interaction 0.292 0.846 0.234
Inactive 1.00 (0.63, 1.60) 0.985 0.73 (0.47, 1.13) 0.153 1.46 (0.87, 2.47) 0.154
Less active Referent Referent Referent
Most active 0.99 (0.61, 1.63) 0.978 0.50 (0.28, 0.91) 0.022 0.67 (0.37, 1.21) 0.184
BMI (per z-score) 1.85 (1.51, 2.25) <0.001 1.82 (1.50, 2.20) <0.001 1.84 (1.52, 2.23) <0.001
 p-value for test of interaction 0.118 0.005 0.414

OR Odds Ratio, BMI Body Mass Index.

Note: separate models were examined for each activity exposure and BMI and coefficients reported are from models without a BMIxActivity interaction, adjusting for potential confounders - education at 26y, income at 53y, childhood social class, family history of arthritis, history of knee injury and health status at 53y. Where there was evidence for an interaction, Figures 1C and 1D show the full stratified odds ratios for BMI and activity in these models.

Martin et al.

Martin et al. BMC Musculoskeletal Disorders 2013 14:219   doi:10.1186/1471-2474-14-219

Open Data