Passive Smoking Induces Atherogenic Changes in Low-Density Lipoprotein

Abstract

Background-According to the American Heart Association, passive smoking is an important risk factor for coronary heart disease (CHD), but the mechanisms underlying this association are not fully understood. We studied the acute effect of passive smoking on the factors that influence the development of CHD: the antioxidant defense of human serum, the extent of lipid peroxidation, and the accumulation of LDL cholesterol in cultured human macrophages, the precursors of foam cells in atherosclerotic lesions. Methods and Results-Blood samples were collected during 2 ordinary working days from healthy, nonsmoking subjects (nϭ10) before and after (up to 5.5 hours) spending half an hour in a smoke-free area (day 1) or in a room for smokers (day 2). Passive smoking caused an acute decrease (1.5 hours after exposure) in serum ascorbic acid (PϽ.001) and in serum antioxidant defense (PϽ.001), a decreased capacity of LDL to resist oxidation (PϽ.01), and the appearance of increased amounts of lipid peroxidation end products in serum (PϽ.01). Finally, LDL isolated from subjects after passive smoking was taken up by cultured macrophages at an increased rate (PϽ.05). Conclusions-Exposure of nonsmoking subjects to secondhand smoke breaks down the serum antioxidant defense, leading to accelerated lipid peroxidation, LDL modification, and accumulation of LDL cholesterol in human macrophages. These data provide the pathophysiological background for the recent epidemiological evidence about the increased CHD risk among passive smokers. (Circulation. 1998;97:2012-2016.)

Effect of Cigar Smoking on the Risk of Cardiovascular Disease, Chronic Obstructive Pulmonary Disease, and Cancer in Men

“…38,39 Another potential reason why cigar smoking may increase the risk of coronary heart disease is the associated high levels of exposure to environmental tobacco smoke. Even cigar smokers who do not inhale are exposed to their own environmental tobacco smoke, a clearly documented risk factor for coronary heart disease [40][41][42][43][44] and COPD. [45][46][47] In summary, our data confirm that cigar smoking is related to a moderate increase in the risk of COPD and cancers of the upper aerodigestive tract and lung, and they add new evidence that cigar smoking is associated with a moderate but significant increase in the risk of coronary heart disease.…”

Why Is Environmental Tobacco Smoke More Strongly Associated with Coronary Heart Disease Than Expected? A Review of Potential Biases and Experimental Data

“…The average concentrations of air nicotine, carbon monoxide, and total particulate concentrations in rabbits exposed to low-dose ETS were 30 pg/m3, 18.8 ppm, and 4.0 ppm, respectively. Bleeding time was shortened as much in rabbits exposed to low as to higher concentrations of ETS (45 (50). Passive smoke exposure has been shown to accelerate arteriosclerotic plaque development in experimental studies of cockerels (51)(52)(53)(54), rabbits (55,56), and rats (57).…”

Antioxidant-Vitamin C: Lung Function; Lung Cancer

“…Free radicals in CS deplete some plasma antioxidants in vitro [122,123], and several studies found lower plasma antioxidant concentrations in smokers in vivo [124][125][126][127][128][129][130]. Less information is available on the effect of CS exposure on plasma antioxidant concentrations in passive smokers [131][132][133][134][135]. It has been difficult to determine whether differences in plasma antioxidants between smokers and non-smokers are actually due to the effect of CS exposure or are due instead to differences in dietary antioxidant intakes or in other covariates.…”