Table 2.
Baseline characteristics of REGARDS participants according to income and baseline depressive symptoms
| Characteristics | Income <$35,000 (n = 12,466) | Income ≥$35,000 (n = 17,011) | ||||
|---|---|---|---|---|---|---|
| CES-D<4 (n = 10,464) | CES-D ≥ 4 (n = 2002) | P-value | CES-D<4 (n = 15,760) | CES-D ≥ 4 (n = 1251) | P-value | |
| Sociodemographics | ||||||
| Age, M (SD) | 67.4 (9.2) | 63.9 (9.7) | <.001 | 63.8 (9.2) | 62.4 (9.8) | <.001 |
| Female, n (%) | 6398 (61.1%) | 1410 (70.4%) | <.001 | 7583 (48.1%) | 846 (67.6%) | <.001 |
| Male, n (%) | 4066 (38.9%) | 592 (29.6%) | – | 8177 (51.9%) | 405 (32.4%) | – |
| African American, n (%) | 5278 (50.4%) | 1172 (58.5%) | <.001 | 5144 (32.6%) | 530 (42.4%) | <.001 |
| White, n (%) | 5186 (49.6%) | 830 (41.5%) | – | 10,616 (67.4%) | 721 (57.6%) | – |
| Less than high-school education, n (%) | 2050 (19.6%) | 602 (30.1%) | <.001 | 862 (5.5%) | 178 (14.2%) | <.001 |
| High-school education and above, n (%) | 8414 (80.4%) | 1400 (69.9%) | – | 14,898 (94.5%) | 1073 (85.8%) | – |
| No health insurance, n (%) | 997 (9.5%) | 313 (15.6%) | <.001 | 534 (3.4%) | 81 (6.5%) | <.001 |
| Health insurance, n (%) | 9459 (90.4%) | 1689 (84.4%) | – | 15,210 (96.5%) | 1168 (93.4%) | – |
| Missing, n (%) | 8 (0.1%) | 0 (0.0%) | – | 16 (0.1%) | 2 (0.2%) | – |
| Region, n (%) | – | – | <.001 | – | – | <.001 |
| Stroke belt* | 3835 (36.6%) | 790 (39.5%) | – | 5134 (32.6%) | 430 (34.4%) | – |
| Stroke buckle† | 2090 (20.0%) | 436 (21.8%) | – | 3345 (21.2%) | 315 (25.2%) | – |
| Nonstroke belt or buckle | 4539 (43.4%) | 776 (38.8%) | – | 7281 (46.2%) | 506 (40.4%) | – |
| General health and medical conditions | ||||||
| Self-reported general health, n (%) | – | – | <.001 | – | – | <.001 |
| Poor, fair, good | 6427 (61.4%) | 1630 (81.4%) | – | 6784 (43.0%) | 892 (71.3%) | – |
| Excellent, very good | 4016 (38.4%) | 369 (18.4%) | – | 8944 (56.8%) | 356 (28.5%) | – |
| Missing | 21 (0.2%) | 3 (0.1%) | – | 32 (0.2%) | 3 (0.2%) | – |
| History of CHD‡ | 2044 (19.5%) | 495 (24.7%) | <.001 | 2436 (15.5%) | 228 (18.2%) | <.001 |
| Missing | 188 (1.8%) | 50 (2.50%) | – | 289(1.8%) | 31 (2.5%) | – |
| Cardiovascular disease (CVD), n (%)§ | 2785 (26.6%) | 661 (33.0%) | <.001 | 3046 (19.3%) | 325 (26.0%) | <.001 |
| Diabetes, n (%)∥ | 2673 (25.5%) | 642 (32.1%) | <.001 | 2627 (16.7%) | 305 (24.4%) | <.001 |
| Missing | 433 (4.1%) | 80 (4.0%) | – | 534 (3.4%) | 38 (3.0%) | – |
| COPD, n (%) | 1005 (9.6%) | 249 (12.4%) | <.001 | 1300 (8.2%) | 154 (12.3%) | <.001 |
| Physical component score on SF-12 scale, M (SD) | 44.6 (10.9) | 39.1 (11.8) | <.001 | 48.7 (9.3) | 43.2 (12.6) | <.001 |
| Impaired cognitive status (cognitive score ≤ 4) | 830 (7.9%) | 240 (12.0%) | <.001 | 711 (4.5%) | 106 (8.5%) | <.001 |
| Missing | 2304 (22.0%) | 359 (17.9%) | – | 2870 (18.2%) | 148 (11.8%) | – |
| Elevated perceived stress (PSS ≥ 5) | 3026 (28.9%) | 1488 (74.3%) | <.001 | 3252 (20.6%) | 820 (65.5%) | <.001 |
| Depressive Symptoms | ||||||
| Depression at 5-y follow-up (CES-D-4) n = 20,925 | 723 (6.9%) | 485 (24.2%) | <.001 | 745 (4.7%) | 300 (24.0%) | <.001 |
| Missing | 3471 (33.2%) | 878 (43.9%) | – | 3795 (24.1%) | 408 (32.6%) | – |
| Depression at 7-y follow-up (CES-D-4) n = 12,448 | 392 (3.7%) | 257 (12.8%) | <.001 | 475 (3.0%) | 133 (10.6%) | <.001 |
| Missing | 6333 (60.5%) | 1393 (69.6%) | – | 8502 (53.9%) | 801 (64.0%) | – |
| Physiological risk factors | ||||||
| Body mass index, kg/m2, M (SD) | 29.6 (6.5) | 30.8 (7.4) | <.001 | 28.9 (5.7) | 30.1 (6.5) | <.001 |
| Systolic blood pressure, mm Hg, M (SD) | 130.0 (17.2) | 130.2 (18.6) | .71 | 125.7 (15.7) | 126.4 (17.1) | .17 |
| Total cholesterol, mg/dL, M (SD) | 192.4 (41.4) | 195.1 (44.7) | .011 | 191.3 (38.6) | 193.8 (40.0) | .032 |
| High-density lipoprotein, mg/dL, M (SD) | 51.7 (15.9) | 52.3 (16.4) | .12 | 51.8 (16.4) | 52.8 (16.2) | .040 |
| QT interval, corrected for heart rate, ms, M (SD.) | 408.8 (24.6) | 410.7 (24.6) | .001 | 406.1 (22.7) | 408.8 (23.1) | <.001 |
| High-sensitivity C-reactive protein, mg/L, median, IQR | 2.6 (1.1, 5.9) | 3.4 (1.3, 7.7) | <.001 | 1.9 (0.8, 4.3) | 2.5 (1.1, 5.9) | <.001 |
| Albumin to creatinine ratio, mg/g, median, IQR | 8.6 (5.1,20.1) | 9.1 (5.3, 23.0) | .031 | 6.7 (4.4, 13.4) | 7.4 (4.7, 15.6) | <.001 |
| Medications | ||||||
| Antihypertensive medication use, n (%) | 6007 (57.4%) | 1253 (62.6%) | <.001 | 7272 (46.1%) | 654 (52.3%) | <.001 |
| Missing, n (%) | 126 (1.2%) | 23 (1.1%) | – | 161 (1.0%) | 23 (1.8%) | – |
| Statin use, n (%) | 3324 (31.8%) | 645 (32.2%) | .67 | 4916 (31.2%) | 402 (32.1%) | .49 |
| Missing, n (%) | 21 (0.2%) | 6 (0.3%) | – | 40 (0.3%) | 3 (0.2%) | – |
| Aspirin use, n (%) | 4556 (43.5%) | 900 (45.0%) | .24 | 6816 (43.2%) | 514 (41.1%) | .14 |
| Missing, n (%) | 7 (0.1%) | 1 (<1%) | – | 7 (<1%) | 1 (0.1%) | – |
| Antidepressant use, n (%) | 1330 (12.7%) | 550 (27.5%) | <.001 | 1832 (11.6%) | 371 (29.7%) | <.001 |
| Missing, n (%) | 21 (0.2%) | 6 (0.3%) | – | 40 (0.3%) | 3 (0.2%) | – |
| Behavioral risk factors | ||||||
| Self-reported smoking, pack years, M (SD.) | 15.0 (24.9) | 16.6 (26.0) | .010 | 12.1 (21.2) | 13.7 (23.0) | .010 |
| Current smoking, n (%) | 1746(16.7%) | 569 (28.4%) | <.001 | 1714 (10.9%) | 230 (18.4%) | <.001 |
| Former smokers, n (%) | 4153 (39.7%) | 631 (31.5%) | – | 6580 (41.8%) | 469 (37.5%) | – |
| Never smokers, n (%) | 4532 (43.3%) | 798 (39.9%) | – | 7398 (46.9%) | 543 (43.4%) | – |
| Missing, n (%) | 33 (0.3%) | 4 (0.2%) | – | 68 (0.4%) | 9 (0.7%) | – |
| Alcohol use, n (%) | – | – | .14 | – | – | <.001 |
| Heavy | 288 (2.8%) | 69 (3.4%) | – | 755 (4.8%) | 60 (4.8%) | – |
| Moderate | 2542 (24.3%) | 460 (23.0%) | – | 6242 (39.6%) | 380 (30.4%) | – |
| None | 7431 (71.0%) | 1410 (70.4%) | – | 8483 (53.8%) | 780 (62.4%) | – |
| Missing, n (%) | 203 (1.9%) | 63 (3.1%) | – | 280(1.8%) | 31 (2.5%) | – |
| Physical inactivity, n (%) | 6357 (60.8%) | 1006 (50.2%) | <.001 | 10,977 (69.7%) | 699 (55.9%) | <.001 |
| Missing, n (%) | 182 (1.7%) | 21 (1.0%) | – | 211 (1.3%) | 24 (1.9%) | – |
| Medication nonadherence, n (%) | 2780 (26.6%) | 719 (35.9%) | <.001 | 4036 (25.6%) | 419 (33.5%) | <.001 |
| Missing, n (%) | 882 (8.4%) | 147 (7.3%) | – | 1581 (10.0%) | 94 (7.5%) | – |
IQR = interquartile range; M = mean; n = total number assuming no missing data; PSS = Perceived Stress Scale; SD = standard deviation.
¶
Indicates a statistically significant P-value.
#
Indicates a nonstatistically significant P-value.
**
Defined as a score ≥4 on the 4-item Center for Epidemiologic Studies Depression scale at one of the 2 follow-up periods, 5 and 7 y after enrollment in REGARDS.
*
Stroke belt defined as the states of Alabama, Arkansas, Louisiana, Mississippi, Tennessee, and the noncoastal regions within the states of North Carolina, South Carolina, and Georgia.
†
Stroke buckle defined as coastal regions within the states of North Carolina, South Carolina, and Georgia.
‡
History of CHD was defined as either a self-reported history, echocardiogram evidence of a myocardial infarction, history of a percutaneous coronary intervention, or coronary artery bypass surgery.
§
CVD defined as baseline coronary heart disease, stroke, periphery artery disease, or aortic aneurism.
∥
Diabetes defined as fasting blood glucose ≥126 or random glucose >200 mL per dL or oral hypoglycemic or insulin use.