Table 1. Baseline Characteristics of the Study Population in 2011.
| Variable | All participants (n = 789 532) | Participant groupa | P value | ||||
|---|---|---|---|---|---|---|---|
| Quitter (n = 114 959) | Reducer I (n = 60 767) | Reducer II (n = 111 890) | Sustainer (n = 376 393) | Increaser (n = 125 523) | |||
| Age, mean (SD), y | 52.2 (8.5) | 53.3 (8.8) | 53.9 (9.4) | 51.9 (8.3) | 52.0 (8.3) | 52.0 (8.6) | <.001 |
| Sex, No. (%) | |||||||
| Female | 33 063 (4.2) | 4811 (4.2) | 4072 (6.7) | 4501 (4.0) | 12 765 (3.4) | 6914 (5.5) | <.001 |
| Male | 756 469 (95.8) | 110 148 (95.8) | 56 695 (93.3) | 107 389 (96.0) | 363 628 (96.6) | 118 609 (94.5) | <.001 |
| Alcohol consumption, No. (%) | |||||||
| None | 203 562 (25.8) | 32 916 (28.6) | 17 800 (29.3) | 28 038 (25.1) | 93 169 (24.8) | 31 639 (25.2) | <.001 |
| Mild | 278 957 (35.3) | 43 483 (37.8) | 23 939 (39.4) | 41 800 (37.4) | 128 661 (34.2) | 41 074 (32.7) | NA |
| Moderate | 178 391 (22.6) | 22 745 (19.8) | 11 900 (19.6) | 25 469 (22.8) | 89 670 (23.8) | 28 607 (22.8) | NA |
| Heavy | 128 622 (16.3) | 15 815 (13.8) | 7128 (11.7) | 16 583 (14.8) | 64 893 (17.2) | 24 203 (19.3) | NA |
| Regular physical activity, No. (%) | |||||||
| None | 632 538 (80.1) | 85 519 (74.4) | 47 665 (78.4) | 89 733 (80.2) | 307 234 (81.6) | 102 387 (81.6) | <.001 |
| Regular | 156 994 (19.9) | 29 440 (25.6) | 13 102 (21.6) | 22 157 (19.8) | 69 159 (18.4) | 23 136 (18.4) | <.001 |
| Anthropometrics, mean (SD) | |||||||
| Height, cm | 168.4 (6.4) | 168.4 (6.4) | 167.5 (6.8) | 168.5 (6.4) | 168.5 (6.3) | 168.1 (6.6) | <.001 |
| Weight, kg | 68.0 (10.2) | 69.5 (10.0) | 67.1 (10.5) | 67.9 (10.2) | 67.8 (10.1) | 67.6 (10.4) | <.001 |
| Waist circumference, cm | 83.5 (7.7) | 84.8 (7.5) | 83.4 (7.9) | 83.4 (7.7) | 83.3 (7.7) | 83.3 (7.8) | <.001 |
| BMI | 23.9 (3.0) | 24.5 (2.9) | 23.8 (3.0) | 23.9 (3.0) | 23.8 (3.0) | 23.9 (3.0) | <.001 |
| Blood pressure, mmHg | |||||||
| Systolic | 124.4 (14.3) | 125.4 (14.2) | 124.8 (14.7) | 124.3 (14.2) | 124.3 (14.3) | 124.2 (14.4) | <.001 |
| Diastolic | 78.2 (9.8) | 78.7 (9.8) | 78.1 (9.9) | 78.2 (9.8) | 78.1 (9.8) | 78.0 (9.9 | <.001 |
| Comorbidities, No. (%) | |||||||
| Hypertension | 241 806 (30.6) | 39 122 (34.0) | 19 900 (32.8) | 33 599 (30.0) | 111 891 (29.7) | 37 294 (29.7) | <.001 |
| Diabetes | 103 139 (13.1) | 15 738 (13.7) | 8694 (14.3) | 14 194 (12.7) | 48 059 (12.8) | 16 454 (13.1) | <.001 |
| Dyslipidemia | 160 062 (20.3) | 27 356 (23.8) | 12 504 (20.6) | 22 306 (19.9) | 73 550 (19.5) | 24 346 (19.4) | <.001 |
| CKD | 31 577 (4.0) | 5707 (5.0) | 2660 (4.4) | 4401 (3.9) | 14 118 (3.8) | 4691 (3.7) | <.001 |
| Laboratory findings | |||||||
| Glucose, mg/dL | 102.2 (27.6) | 103.1 (27.3) | 102.7 (28.6) | 101.9 (27.3) | 101.9 (27.4) | 102.3 (28.8) | <.001 |
| Total cholesterol, mg/dL | 198.2 (36.1) | 200.4 (36.9) | 196.7 (36.6) | 197.8 (36.0) | 197.9 (35.9) | 197.4 (36.0) | <.001 |
| HDL, mg/dL | 52.1 (16.8) | 52.4 (16.5) | 52.2 (17.2) | 51.8 (16.5) | 51.9 (17.0) | 52.3 (16.7) | <.001 |
| LDL, mg/dL | 114.5 (35.3) | 116.7 (34.9) | 113.1 (35.5) | 114.2 (35.3) | 114.2 (35.4) | 113.6 (35.2 | <.001 |
| GFR, mL/min/1.73m2 | 88.9 (37.4) | 87.1 (38.4) | 89.1 (39.1) | 88.8 (34.5) | 89.2 (37.9) | 89.6 (37.0) | <.001 |
| Urban residency, No. (%) | 355 838 (45.1) | 52 520 (45.7) | 26 382 (43.4) | 51 107 (45.7) | 169 748 (45.1) | 56 081 (44.7) | <.001 |
| Household income, No. (%) | |||||||
| Quartile 1 (lowest) | 147 697 (18.7) | 20 380 (17.7) | 12 853 (21.2) | 21 159 (18.9) | 69 275 (18.4) | 24 030 (19.1) | <.001 |
| Quartile 2 | 134 155 (17.0) | 17 867 (15.5) | 11 502 (18.9) | 18 844 (16.8) | 63 258 (16.8) | 22 684 (18.1) | NA |
| Quartile 3 | 213 459 (27.0) | 29 313 (25.5) | 16 158 (26.6) | 30 149 (27.0) | 103 650 (27.5) | 34 189 (27.2) | NA |
| Quartile 4 (highest) | 294 221 (37.3) | 47 399 (41.2) | 20 254 (33.3) | 41 738 (37.3) | 140 210 (37.3) | 44 620 (35.6) | NA |
| Smoking status in 2009, No. (%) | |||||||
| Mild: <10 cigarettes/d | 69 292 (8.8) | 18 417 (16.0) | 2694 (4.4) | 6280 (5.6) | 14 693 (3.9) | 27 208 (21.7) | <.001 |
| Moderate: 10-19 cigarettes/d | 295 770 (37.5) | 47 357 (41.2) | 13 062 (21.5) | 38 056 (34.0) | 125 764 (33.4) | 71 531 (57.0) | NA |
| Heavy: ≥20 cigarettes/d | 424 470 (53.8) | 49 185 (42.8) | 45 011 (74.1) | 67 554 (60.4) | 235 936 (62.7) | 26 784 (21.3) | NA |
| Duration of smoking in 2009, y, No. (%) | |||||||
| <5 | 18 674 (2.4) | 5541 (4.8) | 1474 (2.4) | 1776 (1.6) | 5689 (1.5) | 4194 (3.3) | <.001 |
| 5-9 | 18 229 (2.3) | 3974 (3.5) | 1616 (2.7) | 2054 (1.8) | 6570 (1.8) | 4015 (3.2) | NA |
| 10-19 | 119 613 (15.2) | 19 550 (17.0) | 9391 (15.5) | 15 664 (14.0) | 51 711 (13.7) | 23 297 (18.6) | NA |
| 20-29 | 361 970 (45.9) | 46 801 (40.7) | 24 605 (40.5) | 53 676 (48.0) | 181 015 (48.1) | 55 873 (44.5) | NA |
| ≥30 | 271 046 (34.3) | 39 093 (34.0) | 23 681 (39.0) | 38 720 (34.6) | 131 408 (34.9) | 38 144 (30.4) | NA |
| Pack-years of smoking in 2009, No. (%) | |||||||
| <10 | 129 430 (16.4) | 29 734 (25.9) | 7473 (12.3) | 12 045 (10.8) | 41 525 (11.0) | 38 653 (30.8) | <.001 |
| 10 to <20 | 227 456 (28.8) | 34 095 (29.7) | 12 407 (20.4) | 28 597 (25.6) | 102 102 (27.1) | 50 255 (40.0) | NA |
| 20 to <30 | 222 228 (28.2) | 26 063 (22.7) | 17 264 (28.4) | 30 099 (26.9) | 126 763 (33.7) | 22 039 (17.6) | NA |
| ≥30 | 210 418 (26.7) | 25 067 (21.8) | 23 623 (38.9) | 41 149 (36.8) | 106 003 (28.2) | 14 576 (11.6) | NA |
| Smoking status in 2011, No. (%) | |||||||
| None: 0 cigarettes/d | 114 959 (14.6) | 114 959 (100) | NA | NA | NA | NA | <.001 |
| Mild: <10 cigarettes/d | 60 417 (7.7) | NA | 22 110 (36.4) | 15 576 (13.9) | 14 750 (3.9) | 7981 (6.4) | NA |
| Moderate: 10-19 cigarettes/d | 262 132 (33.2) | NA | 33 173 (54.6) | 65 051 (58.1) | 125 992 (33.5) | 37 916 (30.2) | NA |
| Heavy: ≥20 cigarettes/d | 352 024 (44.6) | NA | 5484 (9.0) | 31 263 (27.9) | 235 651 (62.6) | 79 626 (63.4) | NA |
| Duration of smoking in 2011, y, No. (%) | |||||||
| <5 | 125 034 (15.8) | 114 959 (100) | 2424 (4.0) | 1564 (1.4) | 3838 (1.0) | 2249 (1.8) | <.001 |
| 5-9 | 13 652 (1.7) | 0 | 2387 (3.9) | 2293 (2.0) | 5907 (1.6) | 3065 (2.4) | NA |
| 10-19 | 83 989 (10.6) | 0 | 10 851 (17.9) | 14 961 (13.4) | 41 940 (11.1) | 16 237 (12.9) | NA |
| 20-29 | 294 061 (37.2) | 0 | 21 620 (35.6) | 49 849 (44.6) | 168 298 (44.7) | 54 294 (43.3) | NA |
| ≥30 | 272 796 (34.6) | 0 | 23 485 (38.7) | 43 223 (38.6) | 156 410 (41.6) | 49 678 (39.6) | NA |
| Pack-years of smoking in 2011, No. (%) | |||||||
| <10 | 124 411 (15.8) | 25 093 (21.8) | 27 060 (44.5) | 20 627 (18.4) | 36 489 (9.7) | 15 142 (12.1) | <.001 |
| 10 to <20 | 224 677 (28.5) | 31 292 (27.2) | 22 920 (37.7) | 45 227 (40.4) | 96 270 (25.6) | 28 968 (23.1) | NA |
| 20 to <30 | 214 052 (27.1) | 26 271 (22.9) | 7405 (12.2) | 25 659 (22.9) | 121 748 (32.4) | 32 969 (26.3) | NA |
| ≥30 | 226 392 (28.7) | 32 303 (28.1) | 3382 (5.6) | 20 377 (18.2) | 121 886 (32.4) | 48 444 (38.6) | NA |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); CKD, chronic kidney disease; GFR, glomerular filtration rate; HDL, high-density lipoprotein; LDL, low-density lipoprotein; NA, not applicable.
SI conversion factor: To convert glucose to millimoles per liter, multiply by 0.0555; HDL, LDL, and total cholesterol to millimoles per liter, multiply by 0.0259.
a
Quitters were defined as those who stopped smoking; reducers, those who decreased the number of cigarettes smoked per day by 50% or more (reducers I) or by 20% to 50% (reducers II); sustainers, those who maintained (decreased or increased) the number of cigarettes smoked per day by less than 20%; and increasers, those who increased the number of cigarettes smoked per day by 20% or more.