Table 3.
Multiple-Variable Linear Mixed Models of Calcium Absorption
| Fractional Calcium Absorption (FCA) |
Net Calcium Absorption (NCA) |
||||
|---|---|---|---|---|---|
| Variable | Slope | P value | Slope | P Value | |
| Age, years | −0.0035 | 0.031 | - | - | |
| Kilocalories, day | −0.0004 | 0.004 | −0.199 | 0.034 | |
| Carbohydrates, g/day | +0.0015 | 0.002 | +0.796 | 0.081 | |
| Fat, g/day | +0.0032 | 0.015 | +1.976 | 0.050 | |
| Fiber, g/day | −0.0052 | 0.008 | −4.422 | 0.027 | |
| Calcium, mg/day | −0.0005 | 0.026 | −0.065 | <0.001 | |
| Potassium, mg/day | +0.0001 | 0.004 | −0.058 | 0.030 | |
| Vitamin D, IU/day | −0.0003 | 0.066 | - | - | |
| GFR, mL/minute | - | - | +0.981 | 0.061 | |
| PTH, pg/dL | +0.0009 | 0.083 | - | - | |
| 1,25(OH)2D, pg/mL | +0.0008 | 0.052 | +1.063 | 0.007 | |
| Model Root Mean Square Error | 0.044 TFCA | 52 mg calcium/day | |||
| Square of Correlation between predicted and actual calcium absorption values | 0.748 | 0.726 | |||
| We analyzed data from the proton pump inhibitor study and the baseline visit from the vitamin D insufficiency study. We excluded two outliers and subjects with no missing data, yielding 74 observations. | We analyzed data from all three calcium absorption studies. We excluded 3 outliers and subjects with missing data, yielding 111 observations. | ||||