Table 3.
Cross-sectional analysis at baseline: Current impact of cumulative lifetime smoking and OA symptoms for patients with radiographically confirmed knee OA, beta coefficients (95% confidence intervals (CI))
| Mean (Standard Deviation) | [high] pack years vs Never Smoked Beta coefficients (95%CI) | [low] pack years vs Never Smoked Beta coefficients (95%CI) | ||
|---|---|---|---|---|
| Pain | High: 4.6 (4.0) Low: 4.2 (4.0) Never: 3.9 (3.9) |
Negative beta indicates less pain | ||
| Crude | 0.69 (0.29 to 1.09) | 0.26 (−0.16 to 0.69) | ||
| Multivariable-adjusted§ | 0.36 (0.01 to 0.71) | 0.23 (−0.11 to 0.57) | ||
|
| ||||
| Stiffness | High: 2.5 (1.8) Low: 2.4 (1.8) Never: 2.2 (1.8) |
Negative beta indicates less stiffness | ||
| Crude | 0.27 (0.09 to 0.46) | 0.13 (−0.06 to 0.33) | ||
| Multivariable-adjusted§ | 0.20 (0.03 to 0.37) | 0.14 (−0.03 to 0.30) | ||
|
| ||||
| Function | High: 13.8 (12.6) Low: 13.5 (13.4) Never: 12.4 (12.7) |
Negative beta indicates better function | ||
| Crude | 1.39 (0.09 to 2.69) | 1.05 (−0.32 to 2.41) | ||
| Multivariable-adjusted§ | 0.60 (−0.48 to 1.69) | 0.98 (−0.08 to 2.03) | ||
|
| ||||
| Joint Space Width | High: 4.9 mm (1.6) Low: 5.1 mm (1.5) Never: 5.0 mm (1.6) |
Positive beta indicates better JSW | ||
| Crude | −0.08 (−0.24 to 0.07) | 0.16 (−0.01 to 0.32) | ||
| Multivariable-adjusted§ | −0.05 (−0.19 to 0.09) | 0.15 (0.02 to 0.28) | ||
§
Adjusted for current smoking status, age (linear term), sex, race, education, K-L grade, and SF12 physical component scores