Table 2.
Odds ratio (OR) [95% confidence interval (CI)] for the association of sleep quality, a single item from the Pittsburgh Sleep Quality Index (PSQI) with knee pain outcomes stratified by baseline widespread pain status
| Sleep quality in past week in the PSQI | ||||
|---|---|---|---|---|
| Knee pain outcomes | 0,1=Poor (Referent group) | 2=Fairly good | 3 =Very good | p-trend |
| Consistent frequent knee pain | ||||
| Cross-sectional association for prevalent consistent frequent knee pain (N=4640) | ||||
| Knee (n/N)1 | 376/824 (45.6%) | 887/2582 (34.4%) | 342/1234 (27.7%) | |
| OR (95% CI)2 | 1.0 (ref) | 0.84 (0.68, 1.03) | 0.69 (0.54, 0.90) | 0.005 |
| Longitudinal association for incident consistent frequent knee pain (N=2646) | ||||
| Knee (n/N) | 88/385 (17.6%) | 309/1503 (61.7%) | 104/758 (20.8%) | |
| OR (95% CI) | 1.0 (ref) | 1.07 (0.84, 1.36) | 0.80 (0.60, 1.07) | 0.08 |
| Knee pain worsening (N=4658) | ||||
| Widespread pain absence (N=2746) | ||||
| Knee (n/N) | 87/358 (24.3%) | 304/1476 (20.6%) | 159/912 (17.4%) | |
| OR (95% CI) | 1.0 (ref) | 0.86 (0.62, 1.21) | 0.70 (0.48, 1.02) | 0.037 |
| Widespread pain presence (N=1912) | ||||
| Knee (n/N) | 176/470 (37.4%) | 359/1116 (32.1%) | 87/326 (26.7%) | |
| OR (95% CI) | 1.0 (ref) | 0.72 (0.54, 0.96) | 0.53 (0.35, 0.78) | 0.01 |
1
Number of knees: n (knees with pain worsening or incident joint pain) / N (total number of knees)
2
Model adjusted for age (years), sex (men vs. women), race (white vs. non-white), study site, BMI (kg/m2), education level (college and above vs. below college), tobacco use (pack-years), Charlson’s comorbidity index (range 0-9), fatigue (10-point scale), CES-D depression indicator (yes, no), and prescription use of NSAIDs (yes, no).