Table 2.
Characteristics of study population by red blood cell distribution width.
| Characteristics | Red blood cell distribution width | P-value | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Q1 (10.5–12.0%) (n = 2676) |
Q2 (12.1–12.4%) (n = 2732) |
Q3 (12.5–13.0%) (n = 3315) |
Q4 (13.1–31.6%) (n = 3038) |
||||||
| Age [years]a | 40.70 | ±0.36 | 44.25 | ±0.38 | 47.16 | ±0.34 | 50.44 | ±0.38 | <0.001 |
| BMI [kg/m2] | 26.58 | ±0.13 | 27.38 | ±0.14 | 28.45 | ±0.15 | 29.36 | ±0.17 | <0.001 |
| CRP [mg/dL] | 0.29 | ±0.01 | 0.35 | ±0.02 | 0.40 | ±0.01 | 0.60 | ±0.02 | <0.001 |
| Hemoglobin [g/dL] | 14.76 | ±0.05 | 14.84 | ±0.05 | 14.64 | ±0.04 | 13.81 | ±0.05 | <0.001 |
| ASM [%] | 28.22 | ±0.13 | 28.23 | ±0.10 | 27.41 | ±0.12 | 26.45 | ±0.12 | <0.001 |
| RDW [%] | 11.74 | ±0.01 | 12.26 | ±0.003 | 12.69 | ±0.003 | 14.06 | ±0.03 | <0.001 |
| Sex [n (%)]b | |||||||||
| Male | 1335 | (48.1) | 1519 | (55.2) | 1742 | (51.2) | 1369 | (42.1) | <0.001 |
| Female | 1341 | (51.9) | 1213 | (44.8) | 1573 | (48.8) | 1669 | (57.9) | |
| Race/ethnicity [n (%)] | |||||||||
| Non-Hispanic White | 1595 | (79.0) | 1560 | (77.2) | 1707 | (73.5) | 1261 | (63.4) | <0.001 |
| Non-Hispanic Black | 270 | (4.9) | 382 | (6.8) | 608 | (10.1) | 981 | (19.8) | |
| Mexican American | 590 | (6.6) | 583 | (6.5) | 757 | (7.1) | 579 | (6.3) | |
| Other | 221 | (9.4) | 207 | (9.5) | 243 | (9.3) | 217 | (10.5) | |
| Education [n (%)] | |||||||||
| <High School | 603 | (13.6) | 702 | (15.5) | 1014 | (18.7) | 1063 | (23.9) | <0.001 |
| High School | 608 | (23.2) | 649 | (25.4) | 823 | (28.0) | 724 | (26.1) | |
| >High School | 1465 | (63.1) | 1381 | (59.0) | 1478 | (53.3) | 1251 | (50.1) | |
| Household income [n (%)] | |||||||||
| PIR <1 | 368 | (9.6) | 406 | (10.9) | 570 | (12.0) | 594 | (16.0) | <0.001 |
| PIR 1 to <3 | 1021 | (32.5) | 1063 | (33.3) | 1379 | (35.9) | 1380 | (40.5) | |
| PIR ≥3 | 1287 | (58.0) | 1263 | (55.8) | 1366 | (52.1) | 1064 | (43.6) | |
| Smoking pack-years | |||||||||
| Never | 1577 | (58.3) | 1543 | (54.6) | 1777 | (52.5) | 1587 | (50.6) | <0.001 |
| <20 | 829 | (31.9) | 840 | (32.9) | 1026 | (32.5) | 864 | (29.1) | |
| ≥20 | 270 | (9.8) | 349 | (12.5) | 512 | (15.0) | 587 | (20.3) | |
| MVPA [n (%)] | |||||||||
| Low | 1597 | (55.1) | 1713 | (59.2) | 2207 | (62.6) | 2234 | (70.0) | <0.001 |
| High | 1079 | (44.9) | 1019 | (40.8) | 1108 | (37.4) | 804 | (30.0) | |
| Diabetes [n (%)] | |||||||||
| No | 2490 | (95.2) | 2473 | (93.7) | 2955 | (92.6) | 2555 | (87.9) | <0.001 |
| Yes | 186 | (4.8) | 259 | (6.3) | 360 | (7.4) | 483 | (12.1) | |
| Hypertension [n (%)] | |||||||||
| No | 1985 | (78.1) | 1904 | (74.7) | 1994 | (66.6) | 1559 | (59.7) | <0.001 |
| Yes | 691 | (21.9) | 828 | (25.3) | 1321 | (33.4) | 1479 | (40.3) | |
| CVD [n (%)] | |||||||||
| No | 2543 | (96.5) | 2512 | (93.5) | 2962 | (91.8) | 2530 | (86.3) | <0.001 |
| Yes | 133 | (3.5) | 220 | (6.5) | 353 | (8.2) | 508 | (13.7) | |
aWeighted mean ± SE from survey mean (all such values).
bWeighted percentages from survey frequency (all such values).
P for trend was calculated using linear regression for continuous variables; P for difference was calculated using Rao-Scott chi-square test for categorical variables.
BMI, body mass index; CRP, C-reactive protein; ASM, appendicular skeletal muscle mass; RDW, red blood cell distribution width; PIR, poverty income ratio; MVPA, moderate-to-vigorous physical activity; CVD, cardiovascular disease.