Table 1.
Participant Baseline Characteristics
| Dietary caffeine intake | |||||
|---|---|---|---|---|---|
| Q1 ( < = 13 mg/d) | Q2 (13 ~ 98.8 mg/d) | Q3 (98.5 ~ 221 mg/d) | Q4 ( > = 221 mg/d) | p | |
| N | 649 | 642 | 647 | 644 | |
| Age (years) | 46.00 (31.00, 62.00) | 45.00 (31.00, 61.00) | 49.00 (36.00, 63.00) | 50.00 (38.00, 62.00) | < 0.001 |
| Race | |||||
| Mexican American | 101 (15.6%) | 116 (18.1%) | 101 (15.6%) | 65 (10.1%) | < 0.001 |
| Non-Hispanic White | 196 (30.2%) | 207 (32.2%) | 274 (42.3%) | 420 (65.2%) | |
| Non-Hispanic Black | 238 (36.7%) | 167 (26%) | 111 (17.2%) | 58 (9%) | |
| Others | 114 (17.6%) | 152 (23.7%) | 161 (24.9%) | 101 (15.7%) | |
| Sex (Female) | 305 (47%) | 305 (47.5%) | 291 (45%) | 260 (40.4%) | 0.041 |
| Education | |||||
| <=High School diploma | 329 (50.7%) | 309 (48.3%) | 303 (46.9%) | 300 (46.6%) | 0.437 |
| >High School diploma | 320 (49.3%) | 331 (51.7%) | 343 (53.1%) | 344 (53.4%) | |
| Marriage | |||||
|
Married /Living with partner |
343 (52.9%) | 385 (60%) | 408 (63.1%) | 412 (64%) | < 0.001 |
|
Widowed/Separated /Divorced |
155 (23.9%) | 116 (18.1%) | 127 (19.6%) | 149 (23.1%) | |
| Never married | 151 (23.3%) | 141 (22%) | 112 (17.3%) | 83 (12.9%) | |
| Smoke | |||||
| < 100 cigarretes | 554 (85.4%) | 538 (83.8%) | 503 (77.7%) | 444 (68.9%) | < 0.001 |
| >= 100 cigarretes | 95 (14.6%) | 104 (16.2%) | 144 (22.3%) | 200 (31.1%) | |
| Drink | |||||
| < 12 drinks/year | 194 (29.9%) | 169 (26.3%) | 152 (23.5%) | 116 (18%) | < 0.001 |
| >= 12 drinks/year | 455 (70.1%) | 473 (73.7%) | 495 (76.5%) | 528 (82%) | |
| BMI (kg/m2) | 27.96 (24.20, 32.80) | 27.43 (24.17, 32.08) | 27.80 (24.33, 32.52) | 28.18 (24.80, 32.39) | 0.404 |
| Hyperglycemia | 86 (13.3%) | 89 (13.9%) | 109 (16.8%) | 83 (12.9%) | 0.160 |
| Hypertension | 228 (35.1%) | 218 (34%) | 242 (37.4%) | 214 (33.2%) | 0.417 |
| CVD | 60 (9.2%) | 59 (9.2%) | 61 (9.4%) | 52 (8.1%) | 0.827 |
| Cancer | 51 (7.9%) | 49 (7.7%) | 57 (8.8%) | 71 (11%) | 0.127 |
| Comorbidities | |||||
| 0 | 420 (64.7%) | 386 (60.1%) | 380 (58.7%) | 356 (55.3%) | 0.030 |
| < 3 | 214 (33%) | 233 (36.3%) | 243 (37.6%) | 260 (40.4%) | |
| >=3 | 15 (2.3%) | 23 (3.6%) | 24 (3.7%) | 28 (4.3%) | |
| Serum lipids | |||||
| LDL (mmol/L) | 2.90 (2.30, 3.41) | 2.90 (2.35, 3.58) | 3.05 (2.40, 3.70) | 3.08 (2.46, 3.70) | 0.046 |
| HDL (mmol/L) | 1.32 (1.09, 1.60) | 1.29 (1.06, 1.53) | 1.27 (1.06, 1.55) | 1.25 (1.06, 1.55) | 0.163 |
| Total cholesterol (mmol/L) | 4.84 (4.22, 5.61) | 4.89 (4.19, 5.59) | 5.07 (4.32, 5.79) | 5.09 (4.40, 5.83) | < 0.001 |
| Thyroid function | |||||
| TSH (mU/L) | 1.50 (1.02, 2.23) | 1.48 (1.04, 2.12) | 1.43 (1.03, 2.07) | 1.56 (1.11, 2.28) | 0.140 |
| FT3 (pg/mL) | 3.12 (2.90, 3.40) | 3.18 (2.96, 3.41) | 3.15 (2.94, 3.41) | 3.17 (2.95, 3.40) | 0.243 |
| FT4 (pmol/L) | 10.30 (9.00, 11.50) | 10.30 (9.30, 11.50) | 10.30 (9.30, 11.60) | 10.30 (9.00, 11.50) | 0.281 |
| TPOAb (U/mL) | 0.60 (0.30, 1.3) | 0.60 (0.30, 1.60) | 0.60 (0.30, 1.40) | 0.60 (0.30, 1.40) | 0.499 |
| Diet | |||||
| Energy (kcal/d) |
1855.00 (1328.00, 2455.00) |
1932.00 (1402.00, 2553.00) |
1989.00 (1512.50, 2643.50) |
2158.50 (1650.60, 2910.00) |
< 0.001 |
| Protein (gm/d) | 72.66 (50.57, 99.05) | 73.44 (50.16, 96.94) | 77.86 (53.52, 102.75) | 81.08 (57.23, 113.02) | < 0.001 |
| Carbohydrate (gm/d) |
221.83 (164.04, 294.95) |
239.40 (177.41, 318.37) |
240.70 (186.15, 332.27) |
260.88 (191.57, 345.20) |
< 0.001 |
| Fat (gm/d) | 64.28 (40.41, 96.49) | 64.71 (45.22, 99.0) | 73.18 (49.68, 101.31) | 83.03 (56.52, 114.80) | < 0.001 |
| Vitamin D (mcg/d) | 5.40 (1.90, 13.70) | 4.10 (1.60, 11.10) | 5.60 (2.20, 14.45) | 5.50 (2.05, 14.05) | 0.0024 |
| Calcium (mg/d) |
918.00 (569.00, 1404.00) |
849.00 (569.00, 1250.00) |
956.00 (637.00, 1412.00) |
991.50 (644.50, 1503.00) |
< 0.001 |
| Magnesium (mg/d) | 275.00(200.00, 380.00) | 264.50 (205.00, 363.00) | 304.00 (211.00, 399.00) | 318.50 (243.00, 451.00) | < 0.001 |
| Iron (mg/d) | 13.31 (9.06, 21.38) | 13.69 (9.57, 19.61) | 15.18 (10.00, 23.32) | 15.40 (10.45, 23.02) | < 0.001 |
| Zinc (mg/d) | 11.23 (7.33, 18.96) | 10.36 (7.08, 16.10) | 12.76 (7.93, 20.26) | 12.56 (8.06, 20.68) | < 0.001 |
| Selenium (mg/d) | 106.90 (70.70, 160.40) | 106.95 (73.30, 147.50) | 120.40 (80.30, 171.25) | 122.70 (76.90, 170.60) | < 0.001 |
| Urinary iodine (ug/L) | 135.60 (72.60, 244.90) | 134.75 (70.80, 242.30) | 136.00 (82.45, 219.95) | 129.70 (68.30, 212.60) | 0.207 |
Data were presented as medians (percentile 25-percentile 75) or frequencies (%)