Table 1 Characteristics of eligible participants
Variables | Total (n = 13,816) | Caffeine intake | Statistics | P | ||||
|---|---|---|---|---|---|---|---|---|
≤ 10 mg (n = 3204) | 10–86 mg (n = 3098) | 86–171 mg (n = 2859) | 171–303 mg (n = 2453) | > 303 mg (n = 2202) | ||||
Constipation, n (%) | χ2 = 42.47 | < 0.001 | ||||||
No | 12,403 (90.49) | 2810 (88.58) | 2705 (87.51) | 2611 (92.60) | 2261 (91.51) | 2016 (92.29) | ||
Yes | 1413 (9.51) | 394 (11.42) | 393 (12.49) | 248 (7.40) | 192 (8.49) | 186 (7.71) | ||
Age, years. n (%) | χ2 = 278.56 | < 0.001 | ||||||
≤ 40 | 4837 (38.65) | 1286 (47.79) | 1254 (44.93) | 981 (38.26) | 723 (34.43) | 593 (27.78) | ||
40–65 | 5843 (45.58) | 1146 (33.39) | 1156 (39.76) | 1197 (45.05) | 1134 (49.04) | 1210 (60.70) | ||
> 65 | 3136 (15.77) | 772 (18.82) | 688 (15.32) | 681 (16.69) | 596 (16.54) | 399 (11.52) | ||
Gender, n (%) | χ2 = 110.84 | < 0.001 | ||||||
Male | 6983 (49.03) | 1499 (46.02) | 1420 (42.33) | 1406 (46.47) | 1343 (52.12) | 1315 (58.23) | ||
Female | 6833 (50.97) | 1705 (53.98) | 1678 (57.67) | 1453 (53.53) | 1110 (47.88) | 887 (41.77) | ||
Race, n (%) | χ2 = 870.37 | < 0.001 | ||||||
Non-Hispanic White | 6838 (71.74) | 1116 (56.74) | 1192 (63.28) | 1367 (70.27) | 1494 (80.02) | 1669 (88.38) | ||
Non-Hispanic Black | 2763 (10.98) | 1059 (21.79) | 721 (13.77) | 509 (10.17) | 321 (6.51) | 153 (2.66) | ||
Others | 4215 (17.29) | 1029 (21.47) | 1185 (22.95) | 983 (19.56) | 638 (13.47) | 380 (8.96) | ||
PIR, n (%) | χ2 = 74.70 | < 0.001 | ||||||
< 1.3 | 3746 (18.59) | 960 (23.18) | 907 (21.23) | 744 (18.64) | 571 (15.04) | 564 (14.86) | ||
≥ 1.3 | 9070 (75.80) | 2022 (71.95) | 1915 (71.33) | 1890 (75.15) | 1719 (80.05) | 1524 (80.55) | ||
Unknown | 1000 (5.61) | 222 (4.87) | 276 (7.44) | 225 (6.21) | 163 (4.91) | 114 (4.59) | ||
Education level, n (%) | χ2 = 36.17 | < 0.001 | ||||||
Below high school | 3856 (17.84) | 994 (20.24) | 989 (20.70) | 792 (17.94) | 588 (14.39) | 493 (15.93) | ||
High school graduate | 3327 (24.55) | 715 (21.47) | 738 (25.31) | 709 (25.59) | 591 (25.98) | 574 (24.41) | ||
College or above | 6633 (57.61) | 1495 (58.29) | 1371 (53.99) | 1358 (56.48) | 1274 (59.63) | 1135 (59.66) | ||
Drinking, n (%) | χ2 = 118.59 | < 0.001 | ||||||
< 2 times/week | 10,792 (73.84) | 2603 (79.45) | 2553 (79.15) | 2266 (75.48) | 1765 (66.92) | 1605 (68.17) | ||
≥ 2 times/week | 3024 (26.16) | 601 (20.55) | 545 (20.85) | 593 (24.52) | 688 (33.08) | 597 (31.83) | ||
Smoking, n (%) | χ2 = 235.00 | < 0.001 | ||||||
Current non-smokers | 10,728 (76.97) | 2702 (84.41) | 2580 (82.63) | 2293 (80.52) | 1841 (75.85) | 1312 (61.45) | ||
Current smokers | 3088 (23.03) | 502 (15.59) | 518 (17.37) | 566 (19.48) | 612 (24.15) | 890 (38.55) | ||
Physical activity, n (%) | χ2 = 10.55 | 0.228 | ||||||
< 450 MET*min/week | 1702 (12.75) | 388 (11.80) | 382 (12.24) | 355 (13.91) | 304 (12.28) | 273 (13.55) | ||
≥ 450 MET*min/week | 7861 (61.94) | 1814 (61.85) | 1705 (61.19) | 1607 (60.88) | 1466 (64.83) | 1269 (60.97) | ||
Unknown | 4253 (25.30) | 1002 (26.36) | 1011 (26.57) | 897 (25.21) | 683 (22.89) | 660 (25.48) | ||
Diabetes, n (%) | χ2 = 35.24 | < 0.001 | ||||||
No | 9680 (75.53) | 2230 (75.42) | 2194 (76.40) | 1961 (73.44) | 1700 (73.94) | 1595 (78.44) | ||
Treated | 3499 (21.14) | 820 (20.76) | 749 (19.88) | 743 (22.17) | 648 (22.91) | 539 (20.02) | ||
Untreated | 637 (3.32) | 154 (3.83) | 155 (3.72) | 155 (4.40) | 105 (3.15) | 68 (1.54) | ||
Depression, n (%) | χ2 = 14.29 | 0.006 | ||||||
No | 11,528 (82.72) | 2737 (85.04) | 2626 (83.45) | 2410 (83.43) | 2023 (81.36) | 1732 (80.34) | ||
Yes | 2288 (17.28) | 467 (14.96) | 472 (16.55) | 449 (16.57) | 430 (18.64) | 470 (19.66) | ||
BMI, kg/m2, Mean (S.E) | 28.71 (0.12) | 28.92 (0.25) | 28.56 (0.14) | 28.59 (0.20) | 28.97 (0.19) | 28.52 (0.16) | F = 1.87 | 0.132 |
Total energy, kcal, Mean (S.E) | 2165.16 (16.15) | 1989.67 (27.34) | 2063.55 (25.80) | 2115.03 (29.37) | 2204.52 (25.10) | 2452.81 (39.44) | F = 26.25 | < 0.001 |
Total fat, gm, Mean (S.E) | 82.12 (0.83) | 72.89 (1.39) | 77.24 (1.33) | 79.73 (1.42) | 85.21 (1.25) | 95.50 (1.77) | F = 30.00 | < 0.001 |
Dietary fiber, gm, Mean (S.E) | 16.43 (0.23) | 16.16 (0.31) | 15.72 (0.27) | 16.57 (0.40) | 16.47 (0.34) | 17.24 (0.37) | F = 4.34 | 0.005 |
Moisture, gm, Mean (S.E) | 3088.80 (29.72) | 2764.83 (42.62) | 2597.81 (41.33) | 2872.51 (36.57) | 3195.06 (39.89) | 4014.84 (50.09) | F = 149.61 | < 0.001 |
Laxative use, n (%) | χ2 = 10.11 | 0.258 | ||||||
No | 4464 (30.04) | 1006 (29.27) | 994 (31.50) | 959 (30.77) | 811 (30.62) | 694 (28.05) | ||
Yes | 555 (3.26) | 153 (4.12) | 120 (3.25) | 121 (3.37) | 90 (2.74) | 71 (2.84) | ||
Unknown | 8797 (66.69) | 2045 (66.61) | 1984 (65.25) | 1779 (65.86) | 1552 (66.63) | 1437 (69.11) | ||