Table 1.
Baseline characteristics by quartiles of pack-years (PY) among 4482 Cardiovascular Health Study participants without baseline prevalent heart failure
| Variables n (%) or mean (±SD) or median (quartiles 1–3) |
Never-smokers (n = 2556) | Quartiles of PYs of prior smoking for former smokers with over 15 years of smoking cessation (n=1297) | Current smokers (n = 629) | Overall P-value | P-value of differences within former smokers | ||||
|---|---|---|---|---|---|---|---|---|---|
| <8 PY (n = 383) | 8–15 PY (n = 250) | 16–31 PY (n = 352) | ≥32 PY (n = 312) | Never vs. former | Current vs. former | ||||
| Age, years | 74 (±6) | 73 (±5) | 74 (±6) | 73 (±5) | 74 (±6) | 71 (±5) | <0.01 | <0.01 | <0.01 |
| Female | 1808 (71) | 203 (53) | 98 (39) | 112 (32) | 65 (21) | 382 (61) | <0.01 | <0.01 | <0.01 |
| African American | 406 (16) | 55 (14) | 36 (14) | 29 (8) | 16 (5) | 126 (20) | <0.01 | <0.01 | <0.01 |
| Married | 1629 (64) | 287 (75) | 179 (72) | 275 (78) | 237 (76) | 356 (57) | <0.01 | <0.01 | 0.33 |
| College or higher education | 1044 (41) | 191 (50) | 117 (47) | 179 (51) | 150 (48) | 250 (40) | <0.01 | <0.01 | 0.76 |
| Income ≥ $25,000/year | 881 (35) | 178 (47) | 121 (48) | 171 (49) | 150 (48) | 169 (27) | <0.01 | <0.01 | 0.94 |
| Smoke, pack-years | ––– | 4 (±2) | 12 (±2) | 24 (±5) | 53 (±22) | 44 (±28) | <0.01 | <0.01 | <0.01 |
| Duration of smoking cessation, years | ––– | 36 (±11) | 30 (±9) | 27 (±8) | 23 (±6) | 0.0 (±0.0) | <0.01 | <0.01 | <0.01 |
| Exposure to passive smoking | 243 (10) | 25 (7) | 24 (10) | 39 (11) | 32 (10) | 173 (28) | 0.27 | <0.01 | 0.16 |
| Alcohol, drinks per week | 1.3 (±4.3) | 2.7 (±6.4) | 3.2 (±6.5) | 3.6 (±7.8) | 4.4 (±8.1) | 3.8 (±8.1) | <0.01† | 0.09† | 0.01 |
| Self-reported fair to poor general health | 575 (23) | 69 (18) | 48 (19) | 70 (20) | 71 (23) | 187 (30) | 0.21 | <0.01 | 0.47 |
| Instrumental activities of daily living | 1.7 (1.1–2.4) | 1.6 (1.0–2.3) | 1.7 (1.2–2.5) | 1.7 (1.2–2.3) | 2.0 (1.4–2.7) | 2.0 (1.4–2.9) | <0.01† | <0.01† | 0.01 |
| Able to walk 0.5 miles without difficulty | 2160 (85) | 347 (91) | 223 (89) | 311 (88) | 261 (84) | 511 (81) | <0.01 | <0.01 | 0.04 |
| Blocks walked last week | 38 (±54) | 40 (±51) | 50 (±65) | 53 (±63) | 45 (±57) | 30 (±46) | <0.01† | <0.01† | 0.02 |
| Past medical history | |||||||||
| Coronary artery disease | 397 (16) | 67 (18) | 46 (18) | 77 (22) | 79 (25) | 95 (15) | <0.01 | <0.01 | 0.06 |
| Myocardial infarction | 155 (6) | 28 (7) | 20 (8) | 40 (11) | 37 (12) | 48 (8) | <0.01 | 0.07 | 0.11 |
| Hypertension | 1551 (61) | 204 (53) | 138 (55) | 212 (60) | 183 (59) | 332 (53) | 0.05 | 0.13 | 0.23 |
| Diabetes mellitus | 397 (16) | 49 (13) | 32 (13) | 54 (15) | 73 (23) | 77 (12) | <0.01 | <0.01 | <0.01 |
| Stroke | 82 (3) | 7 (2) | 10 (4) | 14 (4) | 20 (6) | 25 (4) | 0.02 | 0.05 | 0.02 |
| Atrial fibrillation | 54 (2) | 3 (1) | 3 (1) | 10 (3) | 13 (4) | 9 (1) | 0.02 | 0.01 | 0.01 |
| Peripheral arterial disease | 262 (10) | 27 (7) | 21 (8) | 33 (9) | 47 (15) | 133 (21) | 0.01 | <0.01 | <0.01 |
| Chronic obstructive pulmonary disease | 255 (10) | 38 (10) | 26 (10) | 39 (11) | 48 (15) | 101 (16) | 0.06 | 0.01 | 0.12 |
| Cancer | 340 (13) | 60 (16) | 27 (11) | 52 (15) | 60 (19) | 81 (13) | 0.02 | 0.04 | 0.05 |
| Clinical examination | |||||||||
| Body mass index, kg/m2 | 27 (±4) | 26 (±4) | 26 (±4) | 27 (±4) | 27 (±4) | 25 (±4) | 0.36 | <0.01 | 0.36 |
| Pulse, beats/minute | 68 (±11) | 67 (±11) | 66 (±11) | 66 (±11) | 67 (±11) | 70 (±12) | <0.01 | <0.01 | 0.59 |
| Systolic BP, mm Hg | 138 (±22) | 135 (±23) | 134 (±21) | 137 (±22) | 137 (±21) | 134 (±22) | 0.01 | 0.08 | 0.40 |
| Diastolic BP, mm Hg | 71 (±11) | 70 (±12) | 71 (±11) | 71 (±11) | 71 (±11) | 70 (±11) | 0.61 | 0.72 | 0.95 |
| Abnormal lung capacity | 126 (5) | 13 (3) | 11 (4) | 14 (4) | 10 (3) | 53 (8) | 0.46 | <0.01 | 0.87 |
| Medications | |||||||||
| ACE inhibitors | 152 (6) | 27 (7) | 22 (9) | 14 (4) | 22 (7) | 30 (5) | 0.13 | 0.06 | 0.10 |
| Beta–blockers | 330 (13) | 46 (12) | 34 (14) | 50 (14) | 40 (13) | 63 (10) | 0.93 | 0.32 | 0.84 |
| Diuretics | 686 (27) | 93 (24) | 61 (25) | 75 (21) | 86 (28) | 127 (20) | 0.18 | 0.10 | 0.32 |
| Aspirin | 1139 (45) | 173 (45) | 127 (51) | 169 (48) | 166 (53) | 285 (45) | 0.02 | 0.13 | 0.18 |
| Laboratory values | |||||||||
| Creatinine, mg/dL | 0.93 (±0.40) | 0.95 (±0.40) | 1.02 (±0.33) | 1.00 (±0.31) | 1.03 (±0.28) | 0.93 (±0.36) | <0.01† | <0.01† | 0.01 |
| Uric acid, mg/dL | 5.5 (±1.5) | 5.5 (±1.4) | 5.9 (±1.5) | 6.0 (±1.5) | 6.0 (±1.6) | 5.5 (±1.5) | <0.01 | <0.01 | <0.01 |
| Albumin, g/dL | 3.98 (±0.29) | 4.03 (±0.31) | 4.00 (±0.29) | 4.02 (±0.29) | 4.02 (±0.28) | 3.99 (±0.29) | 0.01 | 0.22 | 0.65 |
| Hemoglobin, g/dL | 13.8 (±1.3) | 14.1 (±1.4) | 14.3 (±1.3) | 14.4 (±1.3) | 14.4 (±1.3) | 14.3 (±1.3) | <0.01 | <0.01 | <0.01 |
| Total cholesterol, mg/dL | 214 (±39) | 214 (±40) | 208 (±37) | 208 (±36) | 200 (±37) | 211 (±39) | <0.01 | <0.01 | <0.01 |
| Serum insulin, μIU/mL | 17 (±25) | 15 (±11) | 16 (±14) | 16 (±26) | 19 (±29) | 16 (±26) | 0.03† | 0.01† | 0.11 |
| Interleukin-6, units/mL | 1.7 (1.1–2.4) | 1.6 (1.0–2.3) | 1.7 (1.2–2.5) | 1.7 (1.2–2.3) | 2.0 (1.4–2.7) | 2.0 (1.4–2.9) | <0.01† | <0.01† | <0.01 |
| C-reactive protein, mg/dL | 2.4 (1.2–4.2) | 2.2 (1.0–3.9) | 2.0 (0.9–3.8) | 2.1 (1.0–3.7) | 2.8 (1.4–4.5) | 3.4 (1.7–6.4) | 0.01† | <0.01† | <0.01 |
| LV hypertrophy by electrocardiography | 120 (5) | 13 (3) | 8 (3) | 13 (4) | 15 (5) | 30 (5) | 0.58 | 0.69 | 0.73 |
| LV systolic dysfunction by echocardiography | 168 (7) | 25 (7) | 12 (5) | 35 (10) | 42 (14) | 42 (7) | <0.01 | <0.01 | <0.01 |
†
P-values based on independent-samples, nonparametric tests to compare medians across groups
ACE=angiotensin-converting enzyme; BP=blood pressure; LV=left ventricular