TABLE 1.
Baseline characteristics by absolute phosphorus intake quartiles1
| Quartile 1 (n = 2424) | Quartile 2 (n = 2422) | Quartile 3 (n = 2421) | Quartile 4 (n = 2419) | P | |
| Absolute phosphorus intake (mg/d) | 629 (503–737)2 | 993 (905–1078) | 1356 (1259–1471) | 1992 (1769–2355) | |
| Phosphorus density (mg/kcal) | 0.48 (0.40–0.58) | 0.55 (0.47–0.67) | 0.61 (0.51–0.71) | 0.67 (0.57–0.79) | <0.001 |
| Deaths/100 person-years3 | 2.51 ± 0.494 | 2.66 ± 0.71 | 2.43 ± 0.44 | 2.64 ± 0.64 | 0.5 |
| CVD deaths/100 person-years3 | 0.62 ± 0.08 | 1.58 ± 0.6 | 0.98 ± 0.4 | 0.68 ± 0.3 | 1.0 |
| Age (y) | 42.5 ± 0.5 | 42.6 ± 0.6 | 41.0 ± 0.5 | 38.5 ± 0.4 | <0.001 |
| M (%) | 23.5 | 38.2 | 53.0 | 75.6 | <0.001 |
| Black (%) | 14.9 | 10.6 | 8.6 | 6.8 | <0.001 |
| Mexican (%) | 3.8 | 4.9 | 5.0 | 6.4 | <0.001 |
| Poverty (%) | 13.8 | 11.5 | 9.8 | 10.1 | 0.001 |
| Less than high school education (%) | 23.7 | 20.8 | 17.8 | 18.2 | 0.001 |
| No. of moderate-vigorous activities/wk | 3.54 ± 0.16 | 3.81 ± 0.20 | 4.59 ± 0.21 | 4.68 ± 0.21 | <0.001 |
| BMI (kg/m2) | 26.2 ± 0.2 | 26.2 ± 0.2 | 26.1 ± 0.2 | 26.3 ± 0.2 | 0.7 |
| Current smoker (%) | 31.2 | 29.3 | 29.3 | 30.7 | 0.9 |
| Hypertension (%) | 19.6 | 17.6 | 16.0 | 15.8 | 0.02 |
| Microalbuminuria (%) | 8.9 | 8.4 | 7.4 | 6.4 | 0.005 |
| eGFR (mL · min−1 · 1.73 m−2) | 102.6 ± 0.7 | 101.6 ± 0.7 | 102.1 ± 0.6 | 104.4 ± 0.6 | 0.01 |
| Serum phosphorus (mg/dL) | 3.44 ± 0.02 | 3.43 ± 0.01 | 3.43 ± 0.02 | 3.44 ± 0.02 | 1.0 |
| Vitamin D (ng/dL) | 27.5 ± 0.7 | 28.8 ± 0.5 | 30.6 ± 0.6 | 32.6 ± 0.5 | <0.001 |
| Low vitamin D (%) | 17.2 | 13.4 | 8.4 | 5.8 | <0.001 |
1
Means and proportions of baseline characteristics were compared across quartiles by using logistic regression for categorical variables and linear regression for continuous variables. CVD, cardiovascular disease; eGFR, estimated glomerular filtration rate.
2
Median; IQR in parentheses (all such values).
3
Age-standardized death rates.
4
Mean ± SE (all such values).