TABLE 1.
Age-standardized baseline characteristics by quintile of caffeine intake in the Health Professionals Follow-Up Study1
| Caffeine intake quintile |
|||||
| First (n = 8351) | Second (n = 8394) | Third (n = 8375) | Fourth (n = 8475) | Fifth (n = 8657) | |
| Caffeine, mg/d | 9.4 ± 8.62 | 61 ± 29 | 157 ± 49 | 339 ± 100 | 568 ± 185 |
| Age,3 y | 55 ± 10 | 54 ± 10 | 55 ± 10 | 54 ± 10 | 53 ± 9 |
| BMI (kg/m2), % | |||||
| <20.0 | 2 | 1 | 1 | 1 | 1 |
| 20.0–24.9 | 38 | 32 | 31 | 29 | 27 |
| 25.0–29.9 | 49 | 53 | 54 | 55 | 57 |
| ≥30.0 | 9 | 11 | 11 | 12 | 13 |
| Thiazide use, % | 8 | 10 | 10 | 9 | 8 |
| Calcium supplement use, % | 20 | 17 | 16 | 14 | 13 |
| Calcium, mg/d | 864 ± 436 | 817 ± 415 | 784 ± 375 | 826 ± 396 | 696 ± 345 |
| Potassium, g/d | 3.5 ± 1.2 | 3.4 ± 1.1 | 3.4 ± 1.1 | 3.6 ± 1.1 | 3.2 ± 1.0 |
| Magnesium, mg/d | 359 ± 131 | 348 ± 123 | 347 ± 118 | 367 ± 121 | 332 ± 110 |
| Vitamin C, mg/d | 496 ± 497 | 445 ± 460 | 422 ± 444 | 393 ± 419 | 345 ± 408 |
| Total fructose, g/d | 27 ± 16 | 27 ± 15 | 26 ± 15 | 26 ± 14 | 20 ± 11 |
| Oxalate, mg/d | 141 ± 148 | 145 ± 144 | 148 ± 166 | 149 ± 127 | 127 ± 109 |
| Phytate, mg/d | 1020 ± 566 | 947 ± 472 | 927 ± 449 | 954 ± 440 | 820 ± 396 |
| Alcohol intake, g/d | 8.4 ± 14.0 | 9.7 ± 13.9 | 12 ± 15 | 15 ± 18 | 13 ± 16 |
| Fluid intake, L/d | 1.6 ± 0.7 | 1.7 ± 0.7 | 1.8 ± 0.7 | 2.2 ± 0.8 | 2.4 ± 0.8 |
1
Values are standardized to the age distribution of the study population unless otherwise indicated. Values of categorical variables may not sum to 100% because of rounding.
2
Mean ± SD (all such values).
3
Values are not age adjusted.