Table 1. Population characteristics by quartiles of dietary niacin intake.
| Characteristic | Total (n = 7170) | Niacin Intake, mg/d | p | |||
|---|---|---|---|---|---|---|
| Q1(≤16.08) (n = 1793) |
Q2(16.09–21.84) (n = 1792) |
Q3(21.85–28.97) (n = 1792) |
Q4 (≥28.98) (n = 1793) |
|||
| Sex, n (%) | < 0.001 | |||||
| Male | 3407 (47.5) | 487 (27.2) | 687 (38.3) | 917 (51.2) | 1316 (73.4) | |
| Female | 3763 (52.5) | 1306 (72.8) | 1105 (61.7) | 875 (48.8) | 477 (26.6) | |
| Age, years, Mean ± SD | 59.5 ± 11.9 | 61.4 ± 11.8 | 60.5 ± 12.1 | 59.5 ± 12.0 | 56.6 ± 11.2 | < 0.001 |
| Physical activity, n (%) | < 0.001 | |||||
| Sedentary | 3900 (54.4) | 1067 (59.5) | 978 (54.6) | 936 (52.2) | 919 (51.3) | |
| Moderate | 2048 (28.6) | 516 (28.8) | 522 (29.1) | 549 (30.6) | 461 (25.7) | |
| Vigorous | 1222 (17.0) | 210 (11.7) | 292 (16.3) | 307 (17.1) | 413 (23.0) | |
| Smoking status, n (%) | < 0.001 | |||||
| Never | 3817 (53.2) | 992 (55.3) | 1012 (56.5) | 953 (53.2) | 860 (48.0) | |
| Former | 2145 (29.9) | 492 (27.4) | 515 (28.7) | 539 (30.1) | 599 (33.4) | |
| Current | 1208 (16.8) | 309 (17.2) | 265 (14.8) | 300 (16.7) | 334 (18.6) | |
| Race/ethnicity, n (%) | < 0.001 | |||||
| Mexican American | 926 (12.9) | 231 (12.9) | 234 (13.1) | 222 (12.4) | 239 (13.3) | |
| Non-Hispanic white | 3106 (43.3) | 700 (39.0) | 787 (43.9) | 807 (45.0) | 812 (45.3) | |
| Non-Hispanic black | 1501 (20.9) | 444 (24.8) | 380 (21.2) | 349 (19.5) | 328 (18.3) | |
| Others | 1637 (22.8) | 418 (23.3) | 391 (21.8) | 414 (23.1) | 414 (23.1) | |
| Education level, n (%) | < 0.001 | |||||
| Less than high school | 1402 (19.6) | 443 (24.7) | 353 (19.7) | 314 (17.5) | 292 (16.3) | |
| High school | 1670 (23.3) | 435 (24.3) | 413 (23.0) | 430 (24.0) | 392 (21.9) | |
| More than high school | 4098 (57.2) | 915 (51) | 1026 (57.3) | 1048 (58.5) | 1109 (61.9) | |
| Marital status, n (%) | < 0.001 | |||||
| Married | 4211 (58.7) | 949 (52.9) | 1036 (57.8) | 1110 (61.9) | 1116 (62.2) | |
| living with a partner | 331 (4.6) | 68 (3.8) | 82 (4.6) | 76 (4.2) | 105 (5.9) | |
| Living alone | 2628 (36.7) | 776 (43.3) | 674 (37.6) | 606 (33.8) | 572 (31.9) | |
| Family income, n (%) | < 0.001 | |||||
| Low (PIR<1.3) | 1970 (27.5) | 600 (33.5) | 464 (25.9) | 470 (26.2) | 436 (24.3) | |
| Medium (1.3≤PIR<3.5) | 2802 (39.1) | 714 (39.8) | 707 (39.5) | 696 (38.8) | 685 (38.2) | |
| High (PIR≥3.5) | 2398 (33.4) | 479 (26.7) | 621 (34.7) | 626 (34.9) | 672 (37.5) | |
| Body mass index, n (%) | 0.299 | |||||
| <25 kg/m2 | 1694 (23.6) | 406 (22.6) | 453 (25.3) | 408 (22.8) | 427 (23.8) | |
| 25 to <30 kg/m2 | 2432 (33.9) | 594 (33.1) | 593 (33.1) | 617 (34.4) | 628 (35) | |
| ≥30 kg/m2 | 3044 (42.5) | 793 (44.2) | 746 (41.6) | 767 (42.8) | 738 (41.2) | |
| Total energy, Kcal, Mean ± SD | 2028.3 ± 921.1 | 1352.2 ± 549.2 | 1813.0 ± 627.3 | 2142.0 ± 671.5 | 2806.0 ± 1061.6 | < 0.001 |
| Serum cotinine, ng/mL, Median (IQR) | 0.03 (0.01, 0.51) | 0.03(0.01,0.56) | 0.02 (0.01, 0.29) | 0.02 (0.01, 0.30) | 0.03 (0.01,1.97) | < 0.001 |
| Hypertension, n (%) | 3465 (48.3) | 926 (51.6) | 883 (49.3) | 876 (48.9) | 780 (43.5) | < 0.001 |
| High cholesterol, n (%) | 3391 (47.3) | 840 (46.8) | 849 (47.4) | 884 (49.3) | 818 (45.6) | 0.162 |
| Diabetes, n (%) | 1470 (20.5) | 420 (23.4) | 346 (19.3) | 365 (20.4) | 339 (18.9) | 0.003 |
| Coronary heart disease, n (%) | 466 (6.5) | 126 (7) | 122 (6.8) | 111 (6.2) | 107 (6) | 0.53 |
| Stroke, n (%) | 389 (5.4) | 134 (7.5) | 92 (5.1) | 87 (4.9) | 76 (4.2) | < 0.001 |
| Cancer, n (%) | 1013 (14.1) | 258 (14.4) | 291 (16.2) | 238 (13.3) | 226 (12.6) | 0.011 |
| Niacin Intake, mg/d, Mean ± SD | 23.8 ± 11.6 | 12.1 ± 2.9 | 19.0 ± 1.6 | 25.2 ± 2.0 | 38.9 ± 11.6 | < 0.001 |
| COPD, n (%) | 834 (11.6) | 254 (14.2) | 221 (12.3) | 189 (10.5) | 170 (9.5) | < 0.001 |
Abbreviations: COPD, chronic obstructive pulmonary disease; PIR, family poverty income ratio; Q1–Q4, quartiles based on dietary niacin intake.