Smoking without exception adversely affects vascular structure and function in apparently healthy Chinese: Implications in global atherosclerosis prevention

Background Both active and passive smoking are prevalent in China but cardiovascular diseases were less prevalent in the past. We studied the current relationship between surrogate atherosclerosis markers and smoking in Chinese. Methods Endothelium-dependent flow-mediated dilation (FMD) of brachial artery and carotid intima-media thickness (IMT) were measured non-invasively by ultrasound in 616 apparently healthy Chinese (23% smokers), recruited from greater China and the USA. Results The Chinese smokers had significantly impaired FMD (7.0 ± 2.3 vs. 8.2 ± 2.5%, p < 0.001) and endothelium-independent vasodilation (GTN, 17.4 ± 3.9 vs. 18.7 ± 4.1%, p = 0.001) and thicker IMT (0.61 ± 0.13 vs. 0.58 ± 0.12 mm, p = 0.025). 91% of the smokers were male. Both endothelium-dependent (6.9 ± 2.2 vs. 8.0 ± 2.5%, p < 0.001) and independent (17.3 ± 3.5 vs. 18.2 ± 3.7%, p = 0.047) vasodilation were significantly lower in the male smokers than non-smokers, although their age and cholesterol levels were lower. FMD-to-GTN ratio in the smokers were lower (0.41 ± 0.12 vs. 0.45 ± 0.13, p = 0.005). Multivariate analyses confirmed an independent adverse impact of smoking on vascular functions. There were no consistent interactions between subject location and impact of smoking on FMD and IMT. Conclusion In these apparently healthy native and overseas Chinese subjects, smoking is adversely associated with endothelial dysfunction and arterial wall thickening, with serious implication in atherosclerosis prevention.