Table 2.
Association of Physical Functioning with Baseline Chronic Medical Conditions (CMCs), Incident CMCs, and Interactions with Timea
| Model Parameters | Model 1: Baseline CMCs Only |
Model 2: Change-Point Model (two-way interaction) |
Model 3: Change-Point Model (three-way interaction) |
|||
|---|---|---|---|---|---|---|
| IRRb (95% CIc) |
Percent Differenced | IRR (95% CI) |
Percent Difference | IRR (95% CI) |
Percent Difference | |
| Baseline CMCs | 0.962 (0.952, 0.972) | −3.80 | 0.944 (0.934, 0.954) | −5.60 | 0.960 (0.950, 0.970) | −4.00 |
| Time (years) | 0.998 (0.997, 0.999) | −0.23 | 0.996 (0.995, 0.997) | −0.40 | 0.998 (0.997, 0.999) | −0.20 |
| Baseline CMCs × time | 0.997 (0.997, 0.997) | −0.32 | 0.998 (0.997, 0.999) | −0.20 | ||
| New CMC | 1.012 (1.002, 1.022) | 1.20 | 0.995 (0.981, 1.009) | N/A | ||
| New CMC × time | 0.997 (0.996, 0.998) | −0.30 | 0.999 (0.998, 1.00) | N/A | ||
| Baseline CMCs × new CMC | 1.019 (1.009, 1.029) | 1.90 | ||||
| Baseline CMCs × new CMC × time | 0.997 (0.996, 0.998) | −0.30 |
Note: aModels adjusted for age, race/ethnicity, financial strain, marital status, education, hormone use, smoking, body mass index, health status, bodily pain, fracture history, physical activity, and perceptual speed; bIncident rate ratio, calculated by exponentiating beta values; cConfidence interval; dCalculated by subtracting the IRR from 1 and multiplying by 100.