Table 1. Baseline characteristics of the study participants.
| Variable | Never smokers | Smoking cessation | |||
|---|---|---|---|---|---|
| Quitters with BMI increase | Quitters with BMI maintenance | Quitters with BMI decrease | Current smokers | ||
| Number of cases | 1,504,789 | 89,139 | 231,594 | 23,440 | 2,059,725 |
| Age, years | 56.0±11.5 | 51.6±9.7 | 52.4±9.8 | 54.3±11.1 | 51.3±9.4 |
| BMI, kg/m2 | 24.3±2.9 | 25.1±3.0 | 24.6±2.9 | 23.1±3.0 | 24.1±3.1 |
| Change in BMI, kg/m2 | 0 [-0.65 to 0.68] | 1.77 [1.38 to 2.29] | 0.28 [-0.33 to 0.69] | -1.75 [-2.34 to -1.37] | 0 [-0.65 to 0.68] |
| Fasting blood glucose, mg/dL | 102.0±24.5 | 102.9±23.1 | 104.3±27.5 | 107.8±39.5 | 103.2±27.9 |
| Serum total cholesterol, mg/dL | 193.1±36.0 | 204.5±38.6 | 199.1±37.8 | 189.2±38.9 | 198.0±37.1 |
| History of diabetes mellitus | 204,924 (13.6) | 10,611 (11.9) | 35,576 (15.4) | 4,985 (21.3) | 290,842 (14.1) |
| Regular exercise* | 884,948 (58.8) | 54,053 (60.6) | 150,260 (64.9) | 14,492 (61.8) | 1,162,153 (56.4) |
| Alcohol consumption† | |||||
| Nondrinking | 769,612 (51.1) | 26,195 (29.4) | 64,476 (27.8) | 9,242 (39.4) | 512,185 (24.9) |
| Moderate drinking | 655,685 (43.6) | 50,901 (57.1) | 137,619 (59.4) | 11,884 (50.7) | 1,225,750 (59.5) |
| Heavy drinking | 79,492 (5.3) | 12,043 (13.5) | 29,499 (12.7) | 2,314 (9.9) | 321,790 (15.6) |
| Cigarettes smoked per day | |||||
| <10 | - | 6,618 (7.4) | 30,054 (13.0) | 3,215 (13.7) | 211,261 (10.3) |
| 0–19 | - | 29,973 (33.6) | 91,883 (39.7) | 8,889 (37.9) | 814,597 (39.6) |
| 20–29 | - | 41,853 (47.0) | 91,715 (39.6) | 9,488 (40.5) | 895,767 (43.5) |
| ≥30 | - | 10,695 (12.0) | 17,942 (7.8) | 1,848 (7.9) | 138,100 (6.7) |
| Smoking duration | |||||
| <10 years | - | 4,456 (5.0) | 17,618 (7.6) | 1,891 (8.1) | 87,391 (4.2) |
| 10–19 years | - | 14,043 (15.8) | 42,849 (18.5) | 4,466 (19.1) | 262,476 (12.7) |
| 20–29 years | - | 39,231 (44.0) | 92,311 (39.9) | 8,443 (36.0) | 922,807 (44.8) |
| ≥30 years | - | 31,409 (35.2) | 78,816 (34.0) | 8,640 (36.9) | 787,051 (38.2) |
| Pack-years of smoking | |||||
| <10 | - | 13,963 (15.7) | 55,085 (23.8) | 5,768 (24.6) | 331,736 (16.1) |
| 10–19 | - | 23,749 (26.6) | 66,360 (28.7) | 6,304 (26.9) | 616,685 (29.9) |
| 20–29 | - | 23,360 (26.2) | 51,070 (22.1) | 4,991 (21.3) | 557,834 (27.1) |
| ≥30 | - | 28,067 (31.5) | 59,079 (25.5) | 6,377 (27.2) | 553,470 (26.9) |
Data are n (%), median [interquartile range], or mean±standard-deviation values.
*Regular exercise means ≥20 minutes of vigorous-intensity physical activity ≥3 days per week or ≥30 minutes of moderate-intensity physical activity ≥5 days per week, †Daily alcohol consumption was categorized as follows: heavy drinker, ≥30 g/day; moderate drinker, <30 g/day; and nondrinker.
BMI: body mass index.