Effects of cigarette smoking or nicotine replacement on cardiovascular risk factors and parameters of haemorheology

Abstract

Objectives. Cigarette smoking causes cardiovascular (CV) disease, but the relative roles of nicotine and other components of tobacco smoke remain unclear. We investigated the effect of stopping smoking, by using nicotine replacement therapy (NRT), on haemorheology parameters. Design. Open, parallel-group trial (intervention group and control smokers). Setting. Clinic within university department of pharmacology. Subjects. One hundred and ninety-seven males, aged 25-45 years, smoking >20 cigarettes per day. Interventions. One hundred and sixty-four subjects were instructed to stop smoking and received NRT for 12 weeks and 33 acted as controls. After 12 weeks, NRT was discontinued, and all subjects were followed-up at 26 weeks. At the end of the study, the NRT group was divided into abstainers (self-reported, verified by exhaled carbon monoxide <10 ppm) and relapsers, who were unable to remain abstinent. Main outcome measures. Plasma viscosity, fibrinogen, erythrocyte deformability, reactive capillary blood flow, transcutaneous partial oxygen tension (tcpO 2 ) and haematocrit, assessed at 4, 8, 12, and 26 weeks. Results. After 6 months, plasma fibrinogen (9.95 vs. 8.24 lmol L -1 at baseline; P < 0.003), reactive capillary flow (t-p max : 9.3 vs. 11.2 s at baseline; P < 0.005), and tcpO 2 (50.4 vs. 34.9 mmHg at baseline; P < 0.0001) were significantly improved in abstainers, but changes in plasma viscosity and erythrocyte deformability were inconclusive. Other CV risk factors, such as haematocrit and white blood cell count, decreased to a greater extent in abstainers than in relapsers. Expired carbon monoxide concentrations reflected the changes in smoking and decreased in abstainers from 30.4 ppm at baseline to 4.2 ppm; P < 0.0001). Conclusions. Smoking cessation improved CV parameters, and use of nicotine medications did not negate these improvements.

Suppression of Inflammatory Cytokine Production by Carbon Monoxide Involves the JNK Pathway and AP-1

“…The attenuation of IL-6 production by exogenous CO in vitro occurred even at very low concentrations of CO (50 ppm). For comparison, this concentration of CO is close to the levels that can routinely be measured in the exhaled breath of healthy individuals who smoke (30 ppm) (28).…”

Current research on cigarette toxicity: critical appraisal in view of clinical laboratory

“…87 Again haematocrit and white blood cell count decreased extensively in abstainers. 87 On a different account, Galea G et al observed highly significant differences in whole blood viscosity, plasma viscosity, plasma fibrinogen concentrations, packed cell volume and caboxyhaemoglobin concentrations between smokers and non-smokers.…”

“…87 Again haematocrit and white blood cell count decreased extensively in abstainers. 87 On a different account, Galea G et al observed highly significant differences in whole blood viscosity, plasma viscosity, plasma fibrinogen concentrations, packed cell volume and caboxyhaemoglobin concentrations between smokers and non-smokers. 88 Smoking cessation leads quickly to improvement of clinical, functional and laboratory parameters such as reduced carboxyhaemoglobin, increased oxyhemoglobin and increased average expiratory flow between 25 -75% of vital capacity.…”

Maladie cardiovasculaire et voyage aérien : particularités et enjeux

“…La position assise prolongée réalisant une compression veineuse poplitée et/ou fémorale, l'hémoconcen-tration liée à une mauvaise hydratation pendant le vol et une diminution de l'hygrométrie (> 20 %) sont autant de facteurs initiateurs d'une stase veineuse. En outre, le tabagisme (désor-mais interdit au cours du vol) accentue la viscosité sanguine et augmente le taux de fibrinogène circulant [13].…”