Table 3.
Onset of severe knee pain at three years in people aged 50 and over with no knee pain at baseline by body mass index (BMI) category.
| BMI category at baseline | Severe knee pain at 3 years | Unadjusted analysis | Adjusted analysisa | |||||
| n | n (%) | Relative Risk (RR) (95% Confidence Interval (CI)) | RRb (95% CI) | Potential cases avoidedc (% of all incident cases) | RR (95% CI) | RRb (95% CI) | Potential cases avoidedc (% of all incident cases) | |
| Normald | 939 | 50 (5.3) | 1.00 | - | - | 1.00 | - | - |
| Overweight | 785 | 56 (7.1) | 1.34 (0.93, 1.94) | 1.00 | 14 (10.1) | 1.53 (1.03, 2.26) | 1.00 | 20 (14.4) |
| Obese | 223 | 33 (14.8) | 2.78 (1.84, 4.21) | 2.07 (1.39, 3.11) | 17 (12.2) | 2.79 (1.75, 4.47) | 1.85 (1.17, 2.92) | 15 (10.8) |
| Total | 1947e | 139 (7.1) | 31 (22.3) | 35 (25.2) | ||||
a adjusted for age, gender, deprivation, anxiety, depression, previous knee injury, widespread pain measured at baseline
b obesity category compared to overweight
c number of cases which could have been avoided by reducing overweight people to normal and obese people to overweight
d Normal weight category includes individuals who were underweight
e Total number is smaller than in Table 2, because 49 people had incomplete WOMAC data and severity scores could not be calculated.