Table 3.
HR, 95% CI, and β-Coefficients for Risk Predictors in the Parsimonious Prediction Models of LBP (Primary Outcome)
| Covariate | β (SE) | HR (95% CI) | P value | Risk pointa |
|---|---|---|---|---|
| Sex | ||||
| M | Reference | Reference | 0 | |
| F | 0.315 (0.008) | 1.37 (1.35-1.39) | < 0.001 | 32 |
| Age (yr) | ||||
| < 45 | Reference | Reference | 0 | |
| 45-54 | 0.437 (0.009) | 1.55 (1.52-1.58) | < 0.001 | 44 |
| 55-64 | 0.729 (0.010) | 2.07 (2.04-2.11) | < 0.001 | 73 |
| ≥ 65 | 0.979 (0.012) | 2.66 (2.60-2.72) | < 0.001 | 98 |
| Income/Insurance premium (%) | ||||
| High (> 60) | Reference | Reference | 0 | |
| Medium (30-60) | 0.063 (0.008) | 1.07 (1.05-1.08) | < 0.001 | 6 |
| Low (< 30) | 0.036 (0.010) | 1.04 (1.02-1.06) | < 0.001 | 4 |
| Physical activity (times/wk) | ||||
| High (≥ 4) | Reference | Reference | 0 | |
| Moderate (1-3) | –0.007 (0.014) | 0.99 (0.97-1.02) | 0.0030 | –1 |
| Low (none) | 0.017 (0.014) | 1.02 (0.99-1.05) | 0.0589 | 2 |
| Alcohol consumption (times/mo) | ||||
| Rarely (< 2) | Reference | Reference | 0 | |
| Moderate drinker (2-3) | –0.041 (0.008) | 0.96 (0.95-0.97) | < 0.001 | –4 |
| Heavy drinker (≥ 4) | –0.021 (0.013) | 0.98 (0.95-1.01) | 0.1243 | –2 |
| BMI (kg/m2) | ||||
| < 18.5 | –0.231 (0.015) | 0.79 (0.77-0.82) | < 0.001 | –23 |
| 18.5-24.9 | Reference | Reference | 0 | |
| 25.0-29.9 | 0.104 (0.007) | 1.11 (1.09-1.13) | < 0.001 | 10 |
| ≥ 30 | 0.121 (0.019) | 1.13 (1.09-1.17) | < 0.001 | 12 |
| Blood pressure/HTN | ||||
| SBP < 120 and DBP < 80 | Reference | Reference | 0 | |
| SBP 120-139 or DBP 80-89 | 0.0004 (0.007) | 1.00 (0.99-1.02) | 0.9570 | 0 |
| SBP 140-159 or DBP 90-99 | –0.036 (0.012) | 0.97 (0.94-0.99) | 0.0031 | –4 |
| SBP ≥ 160 or DBP ≥ 100 or Rx | –0.082 (0.030) | 0.92 (0.87-0.98) | 0.0054 | –8 |
| Total cholesterol (mg/dL) | ||||
| < 200 | Reference | Reference | 0 | |
| 200-239 | 0.014 (0.007) | 1.01 (1.00-1.03) | 0.0513 | 1 |
| ≥ 240 | –0.029 (0.011) | 0.97 (0.95-0.99) | 0.0053 | –3 |
| Diagnosed IVDD | ||||
| No | Reference | Reference | 0 | |
| Yes | 0.532 (0.012) | 1.70 (1.67-1.74) | < 0.001 | 53 |
| Spinal stenosis | ||||
| No | Reference | Reference | 0 | |
| Yes | 0.207 (0.028) | 1.23 (1.17-1.30) | < 0.001 | 21 |
| History of BMD disorders | ||||
| No | Reference | Reference | 0 | |
| Yes | 0.254 (0.016) | 1.29 (1.25-1.33) | < 0.001 | 25 |
HR: hazard ratio, CI: confidence interval, LBP: low back pain, SE: standard error, BMI: body mass index, HTN: hypertension, SBP: systolic blood pressure, DBP: diastolic blood pressure, Rx: medication due to HTN, IVDD: intervertebral disc degeneration, BMD: bone mineral density.
a
Risk predictors retained in the models at α = 0.01 level of significance using backward selection procedure; The risk points were calculated by multiplying the estimated coefficients by 100 and rounding to the next integer.