Table 3.
Associations between pack-years of smoking in current smokers and endothelial function markers *.
| Model 1 † beta estimate [95% CI] | P-value | Model 2 ‡ beta estimate [95% CI] | P-value | |
|---|---|---|---|---|
| Pack-years of smoking | Estimates for flow-mediated dilation | |||
| Never smoking (ref.) | – | – | – | – |
| >0– < 10 | 0.057 [−0.36; 0.47] | 0.79 | 0.057 [−0.41; 0.52] | 0.81 |
| ≥10– < 20 | −0.24 [−0.69; 0.21] | 0.30 | −0.24 [−0.75; 0.28] | 0.37 |
| ≥20– < 30 | −0.19 [−0.70; 0.32] | 0.46 | −0.11 [−0.67; 0.46] | 0.71 |
| ≥30 | 0.014 [−0.40; 0.43] | 0.95 | 0.061 [−0.42; 0.54] | 0.80 |
| Estimates for baseline brachial artery diameter | ||||
| Never smoking (ref.) | – | – | – | – |
| >0– < 10 | −0.0036 [−0.050; 0.043] | 0.88 | −0.014 [−0.065; 0.036] | 0.58 |
| ≥10– < 20 | −0.035 [−0.085; 0.015] | 0.17 | −0.028 [−0.084; 0.028] | 0.32 |
| ≥20– < 30 | −0.045 [−0.10; 0.012] | 0.12 | −0.071 [−0.13; −0.0094] | 0.024 |
| ≥30 | −0.060 [−0.11; −0.013] | 0.012 | −0.094 [−0.15; −0.042] | 0.00038 |
| Estimates for reactive hyperemia index | ||||
| Never smoking (ref.) | – | – | – | – |
| >0– < 10 | −0.075 [−0.11; −0.040] | < 0.0001 | −0.054 [−0.091; −0.017] | 0.0045 |
| ≥10– < 20 | −0.038 [−0.076; 0.00017] | 0.051 | −0.050 [−0.092; −0.0086] | 0.018 |
| ≥20– < 30 | −0.060 [−0.10; −0.017] | 0.0063 | −0.061 [−0.11; −0.015] | 0.0092 |
| ≥30 | −0.077 [−0.11; −0.041] | < 0.0001 | −0.069 [−0.11; −0.030] | 0.00050 |
| Estimates for baseline pulse amplitude | ||||
| Never smoking (ref.) | – | – | – | – |
| >0– < 10 | 62 [28; 95] | 0.00029 | 46 [9.8; 82] | 0.013 |
| ≥10– < 20 | 26 [−12; 63] | 0.18 | 35 [−5.3; 76] | 0.089 |
| ≥20– < 30 | 63 [21; 105] | 0.0031 | 55 [10; 100] | 0.016 |
| ≥30 | 50 [16; 84] | 0.0044 | 45 [7.4; 83] | 0.019 |
| Estimates for reflection index | ||||
| Never smoking (ref.) | – | – | – | – |
| >0– < 10 | 3.6 [2.4; 4.8] | < 0.0001 | 3.2 [1.9; 4.5] | < 0.0001 |
| ≥10– < 20 | 4.5 [3.3; 5.8] | < 0.0001 | 3.9 [2.4; 5.3] | < 0.0001 |
| ≥20– < 30 | 3.2 [1.8; 4.7] | < 0.0001 | 3.5 [1.9; 5.1] | < 0.0001 |
| ≥30 | 2.8 [1.6; 4.0] | < 0.0001 | 2.9 [1.5; 4.2] | < 0.0001 |
Beta estimates and 95% confidence intervals are derived from a linear regression model modeling for endothelial function. Pack-years were modeled as categories (the reference category was never smoking). Sample sizes (model 2) were for flow-mediated dilation N = 6,143, baseline brachial artery diameter N = 6,660, reactive hyperemia index N = 5,424, baseline pulse amplitude N = 5,424, and reflection index N = 6,706.
Model 1 was adjusted for sex and age.
Model 2 was additionally adjusted for arterial hypertension, waist-to-height ratio, diabetes mellitus, dyslipidemia, family history of myocardial infarction or stroke, socioeconomic status, alcohol consumption, physical activity, depression, passive smoking, smoking prior to examination, prevalent cardiovascular disease (compromising congestive heart failure, coronary artery disease, myocardial infarction, stroke, atrial fibrillation, and peripheral artery disease), and medication use (diabetic drugs, antithrombotic agents, antihypertensives, diuretics, beta-blockers, calcium channel blocker, agents acting on the renin-angiotensin-aldosterone system, and lipid modifying agents).
Statistically significant P-values < 0.05 are given in bold.