Table 1.
Characteristics of participants.
| Variables | Median (IQR) or Percent (%) |
|---|---|
| Continuous variables | |
| Age (years) | 47.70 ± 17.79 |
| BMI (kg/m2) | 28.89 ± 6.85 |
| Aspartate aminotransferase (AST)(U/L) | 25.54 ± 14.01 |
| urine creatinine (mg/dL) | 0.89 ± 0.29 |
| serum fasting glucose (mg/dL) | 102.92 ± 41.51 |
| 1-methyluric acid (umol/L) | 0.91 ± 1.19 |
| 3-methyluric acid (umol/L) | 0.01 ± 0.02 |
| 7-methyluric acid (umol/L) | 0.22 ± 0.34 |
| 1,3-dimethyluric acid (umol/L) | 0.11 ± 0.26 |
| 1,7-dimethyluric acid (umol/L) | 0.42 ± 0.49 |
| 3,7-dimethyluric acid (umol/L) | 0.01 ± 0.02 |
| 1,3,7-trimethyluric acid (umol/L) | 0.03 ± 0.03 |
| 1-methylxanthine (umol/L) | 0.48 ± 0.68 |
| 3-methylxanthine (umol/L) | 0.42 ± 0.61 |
| 7-methylxanthine (umol/L) | 0.67 ± 0.92 |
| 1,3-dimethylxanthine (theophylline) (umol/L) | 0.03 ± 0.07 |
| 1,7-dimethylxanthine (paraxanthine) (umol/L) | 0.29 ± 0.40 |
| 3,7-dimethylxanthine (theobromine) (umol/L) | 0.28 ± 0.44 |
| 1,3,7-trimethylxanthine (caffeine) (umol/L) | 0.09 ± 0.18 |
| 5-acetylamino-6-amino-3-methyluracil (uM/L) | 0.96 ± 1.25 |
| Caffeine intake on the exam day (mg) | 142.74 ± 192.73 |
| Total plain water drank the day before exam (mg) | 1130.95 ± 1213.59 |
| Categorical variables | |
| Gender | |
| Male | 49.8 |
| Female | 50.2 |
| Race | |
| Mexican American | 9.5 |
| Other Hispanic | 10.5 |
| Non-Hispanic White | 36.9 |
| Non-Hispanic Black | 26.8 |
| Other Race—including Multi-Racial | 16.4 |
| Heart disease—ever had a diagnosis | |
| Congestive heart failure | 3.5 |
| Coronary heart disease | 4 |
| Angina | 2.6 |
| Heart attack | 3.8 |
| Smoking | 43.5 |
interquartile range (IQR).