Table 1 Characteristics of participants, 2003–2012 NHANES (n = 3039). RDW red blood cell distribution width, BMI body mass index, COPD chronic obstructive pulmonary disease, CVD cardiovascular disease, ICS inhaled corticosteroids, SABA short-acting Beta2 agonist.
Variables | RDW-tertile | P | ||
|---|---|---|---|---|
Low 10.8–12.3% (n = 997) | Middle 12.4–12.9% (n = 953) | High ≥ 13.0% (n = 1089) | ||
Age, Mean ± SD | 41.5 ± 16.6 | 46.1 ± 17.4 | 50.9 ± 18.0 | < 0.001 |
Female, n (%) | 528 (53) | 538 (56.5) | 676 (62.1) | < 0.001 |
Ethnicity, n (%) | < 0.001 | |||
Non-Hispanic White | 607 (60.9) | 523 (54.9) | 502 (46.1) | |
Mexican American | 99 (9.9) | 102 (10.7) | 84 (7.7) | |
Non-Hispanic Black | 139 (13.9) | 174 (18.3) | 349 (32.0) | |
Other Race | 152 (15.2) | 154 (16.2) | 154 (14.1) | |
BMI, n (%) | < 0.001 | |||
< 25 | 336 (33.7) | 265 (27.8) | 225 (20.7) | |
25–30 | 319 (32.0) | 282 (29.6) | 294 (27.0) | |
> 30 | 342 (34.3) | 406 (42.6) | 570 (52.3) | |
Smoke, n (%) | < 0.001 | |||
Never smoker | 507 (50.9) | 491 (51.5) | 450 (41.4) | |
Former smoker | 228 (22.9) | 233 (24.4) | 322 (29.6) | |
Current smoker | 262 (26.3) | 229 (24.0) | 316 (29.0) | |
Education, n (%) | < 0.001 | |||
< High school diploma | 55 (5.5) | 65 (6.8) | 112 (10.3) | |
Completed high school | 350 (35.1) | 366 (38.4) | 457 (42.0) | |
≥ College | 592 (59.4) | 522 (54.8) | 520 (47.8) | |
Comorbidities, n (%) | ||||
COPD | 104 (10.4) | 127 (13.3) | 233 (21.4) | < 0.001 |
CVD | 87 (8.7) | 116 (12.2) | 232 (21.3) | < 0.001 |
Hypertension | 336 (33.7) | 378 (39.7) | 604 (55.5) | < 0.001 |
Diabetes | 186 (18.7) | 219 (23.0) | 362 (33.2) | < 0.001 |
Asthma related, n (%) | ||||
Eosinophils ≥ 300/uL | 339 (34) | 311 (32.6) | 373 (34.3) | 0.715 |
ICS use | 116 (11.6) | 117 (12.3) | 197 (18.1) | < 0.001 |
SABA use | 182 (18.3) | 166 (17.4) | 278 (25.6) | < 0.001 |
Hemoglobin | 14.6 ± 1.2 | 14.4 ± 1.3 | 14.0 ± 1.2 | < 0.001 |
Asthma attacks, n (%) | ||||
Wheezing | 436(45.1) | 397(41.8) | 539(48.0) | 0.205 |
Asthma emergency | 56 (5.6) | 72 (7.6) | 124 (11.4) | < 0.001 |
Overnight hospitalizations | 106 (10.6) | 128 (13.4) | 259 (23.8) | < 0.001 |
Mortality, n (%) | ||||
All-cause | 78 (7.8) | 115 (12.1) | 241 (22.1) | < 0.001 |
Respiratory-related | 3 (0.3) | 15 (1.6) | 39 (3.6) | < 0.001 |
