Table 2. Clinical characteristics and comorbidities across knee status categories.
| Non-OA (Pain-/ROA-) (Weighted n = 8,131,884) | Pain only (Pain+/ROA-) (Weighted n = 1,093,947) | ROA only (Pain-/ROA+) (Weighted n = 2,819,587) | Painful ROA (Pain+/ROA+) (Weighted n = 1,641,640) | P value | |
|---|---|---|---|---|---|
| Age, years, mean ± SD | 59.4 ± 0.2 | 62.1 ± 0.4 | 66.1 ± 0.3 | 69.4 ± 0.4 | < 0.001 |
| Female, % | 42.9 | 61.4 | 62.2 | 83.2 | < 0.001 |
| Income, % | < 0.001 | ||||
| Low | 24.8 | 30.1 | 24.7 | 32.0 | |
| Mid-low | 24.8 | 29.5 | 27.2 | 27.5 | |
| Mid-high | 26.5 | 21.5 | 24.3 | 23.7 | |
| High | 23.9 | 18.9 | 23.8 | 16.8 | |
| Region, % | < 0.001 | ||||
| Urban | 76.4 | 69.7 | 69.4 | 60.5 | |
| Rural | 23.6 | 30.3 | 30.6 | 39.5 | |
| Education, % | < 0.001 | ||||
| Elementary school | 34.6 | 56.2 | 54.9 | 80.0 | |
| Middle school | 20.5 | 19.4 | 17.4 | 11.6 | |
| High school | 30.1 | 17.4 | 20.0 | 6.9 | |
| College graduation | 14.8 | 7.0 | 7.7 | 1.5 | |
| Marital status, % | 0.066 | ||||
| Married | 98.8 | 98.2 | 99.4 | 99.6 | |
| Unmarried | 1.2 | 1.8 | 0.6 | 0.4 | |
| Alcohol consumption, % | < 0.001 | ||||
| Never | 30.1 | 42.0 | 42.4 | 53.2 | |
| ≤ 1 /week | 42.7 | 37.9 | 37.2 | 34.8 | |
| 2–3 /week | 15.1 | 12.1 | 9.5 | 7.0 | |
| ≥ 4 /week | 12.1 | 8.0 | 10.9 | 5.0 | |
| Smoking status, % | < 0.001 | ||||
| Never smoker | 46.8 | 61.1 | 63.8 | 78.1 | |
| Ex-smoker | 29.3. | 21.6 | 23.0 | 12.2 | |
| Current smoker | 23.9 | 17.3 | 13.2 | 9.7 | |
| Body mass index (kg/m2), mean ± SD | 23.6 ± 0.1 | 23.9 ± 0.2 | 24.6 ± 0.1 | 25.2 ± 0.1 | < 0.001 |
| Hypertension, % | 31.2 | 35.5 | 46.8 | 54.5 | < 0.001 |
| Dyslipidemia, % | 15.6 | 20.1 | 17.8 | 19.7 | 0.006 |
| Diabetes, % | 12.7 | 13.2 | 15.1 | 17.4 | 0.003 |
| Stroke, % | 2.7 | 3.0 | 3.5 | 4.0 | 0.177 |
| Myocardial infarction or angina, % | 4.0 | 5.7 | 5.4 | 5.2 | 0.038 |
| Myocardial infarction, % | 1.3 | 2.2 | 1.7 | 1.5 | 0.536 |
| Angina, % | 2.9 | 3.9 | 4.0 | 4.0 | 0.081 |
| Lung cancer, % | 0.1 | 0.1 | 0.2 | 0.1 | 0.309 |
| Cervical cancer, % | 0.4 | 1.0 | 0.8 | 1.0 | 0.121 |
| Breast cancer, % | 0.6 | 1.0 | 0.5 | 1.1 | 0.179 |
| Colon cancer, % | 0.7 | 0.5 | 0.5 | 0.8 | 0.662 |
| Stomach cancer, % | 1.1 | 1.2 | 1.0 | 0.6 | 0.428 |
| Pulmonary tuberculosis, % | 6.9 | 5.9 | 5.6 | 5.4 | 0.218 |
| Asthma, % | 3.0 | 6.0 | 4.0 | 6.8 | < 0.001 |
| Thyroid disease, % | 3.7 | 7.3 | 4.6 | 5.6 | 0.001 |
| Atopic dermatitis, % | 1.0 | 2.3 | 1.4 | 0.8 | 0.062 |
| Depression, % | 4.4 | 8.7 | 3.5 | 6.5 | < 0.001 |
| Chronic kidney disease, % | 0.5 | 1.2 | 0.8 | 1.0 | 0.075 |
| Hepatitis B, % | 1.9 | 1.4 | 1.0 | 1.3 | 0.087 |
| Hepatitis C, % | 0.3 | 0.4 | 0.3 | 0.2 | 0.754 |
| Liver cirrhosis, % | 0.5 | 0.5 | 1.0 | 0.3 | 0.225 |
Overall P-values were provided for the overall effects of clinical characteristics on the OA categories.