Mortality and morbidity from smoking-induced cardiovascular diseases: the necessity of the cardiologist's involvement and commitment

The risk of cardiovascular events based on the Framingham criteria in Adults Living in Mashhad (Iran)

BACKGROUND AND AIM

Cardiovascular diseases are a problem in low- and middle-income countries, such as Iran. The present research was performed to identify risk factors contributing to cardiovascular diseases and their distributions among the adult population of Mashhad (Iran) using the Framingham criteria.

METHODS

This cross-sectional population-based study performed in 2015 on 2,976 adults living in Mashhad (Iran) using Stratified cluster-random sampling method. Demographic information was acquired by surveyors in the research team using a checklist and referring to a medical laboratory for laboratory assessments. The 10-year risk of cardiovascular diseases for the participants was calculated using the Framingham criteria and was classified into three classes: low risk (<10%), intermediate risk (10-20%), and high risk (>20%). The analysis was done by SPSS Version 11.5 by using the Independent-samples t-test, Kruskal-Wallis, and analysis of variance (ANOVA).

RESULTS

A total of 2,978 participants aged 16-90 participated in our cross-sectional study with an average age of 43.5±14.7 years. Total risk scores among men and women were 7.29±6.3 and 5.8±6.03, respectively. Compared to women, men exhibited a significantly higher risk of cardiovascular diseases (p<0.001). Average heart age among men and women was estimated at 50.37±18.7 and 48.8±17.0 respectively, i.e. significantly older heart age was obtained for men compared to women (p<0.001).

CONCLUSION

According to this study, men are at a great risk of cardiovascular events, so we should develop our screening and educational program especially for this population.

Is smokeless tobacco a risk factor for coronary heart disease? A systematic review of epidemiological studies

BACKGROUND

There is on-going debate about the wisdom of substituting smokeless tobacco products for cigarette smoking as a 'harm reduction' strategy. It is generally believed that health risks associated with smokeless tobacco use (ST) are lower than those with cigarette smoking. However, the population attributable risk of smoking is higher for cardiovascular diseases than for any cancers, and few studies or reviews have considered the cardiovascular outcomes of ST use. A systematic review was therefore carried out to highlight the gaps in the evidence base.

METHODS

Electronic databases were searched, supplemented by screening reference lists, smoking-related websites, and contacting experts. Analytical observational studies of ST use (cohorts, case-control, cross-sectional studies) were included if they reported on cardiovascular disease (CVD) outcomes, or risk factors. Data extraction covered control of confounding, selection of cases and controls, sample size, clear definitions and measurements of the health outcome and ST use. One or two independent reviewers carried out selection, extraction and quality assessments.

RESULTS

A narrative review was carried out. Very few studies were identified; only three from Sweden consider CVD outcomes and these are discrepant. There may be a modest association between use of Swedish snuff (snus) and cardiovascular disease (e.g., relative risk=1.4, 95% confidence interval 1.2-1.6) in one prospective cohort study. Several other studies have considered associations between ST use and intermediate outcomes (CVD risk factors).

CONCLUSIONS

There may be an association between ST use and cardiovascular disease. However, further rigorous studies with adequate sample sizes are required.

Is nicotine a key player or spectator in the induction and progression of cardiovascular disorders?

Cigarette smoking is common in societies worldwide and a growing body of evidence suggests that chronic cigarette smoking may affect the structure and function of cardiovascular system. The chronic exposure to high levels of nicotine, a major component of cigarette smoking, has been observed to play a pathogenic role in the induction and progression of cardiovascular disorders including cardiomyopathy and peripheral vascular disease. Nicotine alters the function of vascular endothelium, initiates the adhesion cascade and stimulates the vascular inflammatory events to induce atherosclerosis and hypertension. Moreover, nicotine has been noted to induce direct coronary spasm and ischemia, which develop coronary artery disease and myocardial infarction. In addition, nicotine stimulates the excessive release of impulses from sinoatrial node that may account for the induction of cardiac arrhythmia. The present review critically discussed the possible detrimental role of chronic nicotine exposure in cardiac and vascular endothelial dysfunction. Moreover, the signaling mechanisms involved in the pathogenesis of nicotine exposure-induced cardiovascular dysfunction have been discussed. In addition, the pharmacological interventions to ameliorate chronic nicotine exposure-induced cardiovascular abnormalities have been delineated.

Risk of Stroke and Myocardial Infarction After Reduction or Cessation of Cigarette Smoking

Background and Purpose— The effect of smoking reduction on cardiovascular disease outcomes has not been studied in Asian populations.

Methods— A total of 475 734 Korean men aged 30 to 58 years, stratified into 9 groups based on smoking status at 2 different time points (1990 and 1992), were followed from 1992 to 2001 for the occurrence of stroke or myocardial infarction (MI) events.

Results— Compared with nonreducing heavy smokers (≥20 cigarettes/d), those who quit smoking showed significantly lower risks of ischemic stroke, subarachnoid hemorrhage, and MI with hazard ratios (95% confidence intervals [CI]) of 0.66 (0.55 to 0.79), 0.58 (0.38 to 0.90), and 0.43 (0.34 to 0.53), respectively. For hemorrhagic stroke, quitters showed lower risk compared with heavy smokers, but the difference was not statistically significant (hazard ratio 0.82, 95% CI: 0.64 to 1.06). Compared with nonreducing heavy smokers, the risks of all stroke combined and MI among reducers tended to decrease, although the reductions were not statistically significant. The risks of subarachnoid hemorrhage and MI in those who reduced from moderate to light smoking tended to be lower than in nonreducing moderate (10 to 19 cigarettes/d) smokers. The association between the reduction of smoking level and the risk of stroke and MI did not change significantly when the analysis was limited to those whose smoking status in 1992 was maintained up to 1994.

Conclusions— Smoking cessation was associated with a decrease in the risks of ischemic stroke, subarachnoid hemorrhage, and MI. More studies are needed to verify the likely health benefits of reducing smoking.

Smoking in Asians: it doesn't stop at vascular endothelium

Smoking is a global risk factor for atherosclerosis, affecting societies all over the world. Smoking exerts its pro-atherogenic effects by triggering the generation of free radicals and by modifying vascular redox signaling. These abnormal vascular responses to cigarette smoking result into impaired endothelial function, decreased nitric oxide bioavailability, increased intima media thickness and finally atherosclerotic plaque formation in human arteries. Importantly, evidence suggests that cigarette smoking may have an effect on vascular smooth muscle cells function, leading to impaired endothelium-independent dilation in response to nitrate, in the brachial artery of healthy smokers. Taken together, it is now well established that smoking induces functional and structural abnormalities in the vascular wall, by mechanisms involving endothelial dysfunction and impairment of vascular smooth muscle cells in human arterial tree.

Cardiovascular disease and the global tobacco epidemic: a wake-up call for cardiologists

The global tobacco epidemic continues unabated with the recruitment of young people, including women, to join the ranks of smokers. Even though cardiovascular diseases account for some of the major tobacco-related morbidity and mortality, cardiologists and their professional societies have lagged behind in the crusade against tobacco. A great opportunity exists for more involvement and leadership role by cardiologists, especially in countries where tobacco control efforts are not well established. For this to happen, there is a need to identify barriers to cardiologists' involvement in tobacco prevention and cessation efforts and to devise locally-relevant strategies to address them. Also, the areas where the contribution of cardiologists can be most fruitful must be identified. Considering that a substantial portion of the future burden of cardiovascular disease will occur among current tobacco users, treating tobacco dependence and supporting tobacco quitters are the most urgent tasks for cardiologists interested in reducing the human toll of tobacco. The cardiovascular community must consider the variety of needs and available resources to fight tobacco in different regions. Recommendations to involve more cardiologists in tobacco control, at the clinical, public health and policy levels, are presented.

Metabolic modulation of carbon monoxide toxicity

Carbon monoxide (CO) gas is a product of the incomplete combustion of carbon-based fuels and substances. From a public health perspective, CO poisoning may be the cause of more than 50% of fatal poisonings in many industrial countries. The adverse effects of CO poisoning may be more widespread because of unreported situations and delayed neurologic effects, which may be linked to CO exposure. Chronic CO effects that are subtle, such as the adverse effects on vascular diseases, may increase the number of people at risk. The apparent role of CO as an important mediator of cell signaling is a paradox and may represent an example of hormesis, i.e. beneficial effects at low concentration but adverse effects at higher concentrations. Nevertheless, because CO can form ligands with iron (heme) and copper sites, the potential for metabolic intervention is likely. Furthermore, CO-induced oxidative stress opens the opportunity for modulating the adverse effects of CO with antioxidants (both water- and lipid-soluble compounds) and various factors involved with reducing oxidative stress. However, consideration must be given to the micro-environment in some situations that could potentially create more oxidation and subsequent metabolic damage if the combinations and concentrations of antioxidants are not correct, i.e. pro oxidant effects. Likewise, it is important that we take precautions in the development of antioxidant adjuvants to use with oxygen therapies in CO poisoning.

Vitamin C prevents the acute atherogenic effects of passive smoking

During passive smoking the body is attacked by an excess of free radicals inducing oxidative stress. In nonsmoking subjects even a short period of passive smoking breaks down serum antioxidant defense (TRAP) and accelerates lipid peroxidation leading to accumulation of their low-density lipoprotein (LDL) cholesterol in cultured human macrophages. We now studied whether these acute proatherogenic effects of secondhand smoke could be prevented by an effective free radical scavenger, vitamin C. Blood samples were collected from nonsmoking subjects (n = 10) as they were consecutively exposed to normal air or cigarette smoke during four separate days. During the last 2 d, a single dose of vitamin C (3 g) was given, which doubled its plasma concentration. Vitamin C did not influence the plasma antioxidant defense or the resistance of LDL to oxidation in normal air, but prevented the smoke-induced decrease in plasma TRAP (p <.001), the decrease in the resistance of LDL to oxidation (p <.05), and the accelerated formation of serum thiobarbituric acid reactive substances (TBARS) (p <.05) otherwise observed 1.5 h after the beginning of passive smoking. Vitamin C protected nonsmoking subjects against the harmful effects of free radicals during exposure to secondhand smoke.