Differential effects of cigarette smoking on cardiovascular disease in females: A narrative review and call to action

OBJECTIVE

Cigarette smoking continues to be a major driver in the incidence and progression of cardiovascular disease (CVD). As females become an increasingly larger fraction of those who smoke it is imperative that the sex-specific effects of smoking be further explored and acted upon.

METHODS

This narrative review describes current evidence on the differential effects of smoking on CVD in females and the need to improve treatment.

RESULTS

Evidence to date suggests that smoking has disproportionately negative effects on the cardiovascular (CV) system in females, especially in those who are younger. Usually, the onset of CVD is later in females than males, but smoking decreases or eliminates this gap. Females are also more likely to develop types of CVD closely tied to smoking, such as ST-elevated myocardial infarctions, with even higher rates among those who are younger. Possible mechanisms for these worse outcomes in females include a complex interplay between nicotine, other products of combusted cigarettes, and hormones. Sex differences also exist in treatment for smoking. In females, Varenicline appears more effective than either Bupropion or nicotine replacement therapy while in males, all three therapies show similar efficacy. Disparities in smoking are also apparent in secondary prevention settings. Females and males are entering secondary prevention with equal rates of smoking, with potentially higher levels of exposure to the byproducts of smoking in females.

CONCLUSIONS

These disproportionately negative outcomes for females who smoke require additional research and these persisting rates of smoking suggest a need for female-specific approaches for treating smoking.

The Impact of Risk Factors for Coronary Heart Disease on Related Disability in Older Irish Adults

OBJECTIVE

The aim of this study is to examine the prevalence of coronary heart disease (CHD)-related disability (hereafter also "disability") and the impact of CHD risk factors on disability in older adults in the Republic of Ireland (ROI) and Northern Ireland (NI).

METHOD

Population attributable fractions were calculated using risk factor relative risks and disability prevalence derived from The Irish Longitudinal Study on Ageing and the Northern Ireland Health Survey.

RESULTS

Disability was significantly lower in ROI (4.1% vs. 8.8%). Smoking and diabetes prevalence rates, and the fraction of disability that could be attributed to smoking (ROI: 6.6%; NI: 6.1%), obesity (ROI: 13.8%; NI: 11.3%), and diabetes (ROI: 6.2%; NI: 7.2%), were comparable in both countries. Physical inactivity (31.3% vs. 54.8%) and depression (10.2% vs. 17.6%) were lower in ROI. Disability attributable to depression (ROI: 16.3%; NI: 25.2%) and physical inactivity (ROI: 27.5%; NI: 39.9%) was lower in ROI.

DISCUSSION

Country-specific similarities and differences in the prevalence of disability and associated risk factors will inform public health and social care policy in both countries.

Assessing and Modifying Coronary Artery Disease Risk in Women

OPINION STATEMENT

Despite continued advances in the field, cardiovascular disease remains the leading cause of death in women in the USA with an annual mortality rate that has remained higher for women as compared to men. The factors leading to this sex difference remain incompletely understood. Likely contributors include atypical symptoms at presentation and lack of recognition of cardiovascular risk by women and their providers alike. In addition, women have a higher burden of comorbidities at the time of disease diagnosis and can have differential pathophysiological mechanisms of their acute events. Women also can develop unique cardiovascular risk factors such as preeclampsia and hypertensive disorders of pregnancy. As a result, when women present with symptoms, even atypical, healthcare providers should increase their index level of suspicion for cardiovascular disease. Even after diagnosis, women are less likely to receive guideline-directed medical therapies and be referred for coronary angiography or cardiac rehabilitation. Thus, greater awareness of and research into the aspects of coronary disease that remain unique to women is critical, as women presenting with coronary disease continue to receive disparate care as compared to men. Improvements in awareness and care and new research avenues may reduce the incidence and complications of cardiovascular disease among women.

Computed tomography coronary angiography in patients with acute myocardial infarction and normal invasive coronary angiography

Background

Three to five percent of patients with acute myocardial infarction (AMI) have normal coronary arteries on invasive coronary angiography (ICA). The aim of this study was to assess the presence and characteristics of atherosclerotic plaques on computed tomography coronary angiography (CTCA) and describe the clinical characteristics of this group of patients.

Methods

This was a multicentre, prospective, descriptive study on CTCA evaluation in thirty patients fulfilling criteria for AMI and without visible coronary plaques on ICA. CTCA evaluation was performed head to head in consensus by two experienced observers blinded to baseline patient characteristics and ICA results. Analysis of plaque characteristics and plaque effect on the arterial lumen was performed. Coronary segments were visually scored for the presence of plaque. Seventeen segments were differentiated, according to a modified American Heart Association classification. Echocardiography performed according to routine during the initial hospitalisation was retrieved for analysis of wall motion abnormalities and left ventricular systolic function in most patients.

Results

Twenty-five patients presented with non ST-elevation myocardial infarction (NSTEMI) and five with ST-elevation myocardial infarction (STEMI). Mean age was 60.2 years and 23/30 were women. The prevalence of risk factors of coronary artery disease (CAD) was low. In total, 452 coronary segments were analysed. Eighty percent (24/30) had completely normal coronary arteries and twenty percent (6/30) had coronary atherosclerosis on CTCA. In patients with atherosclerotic plaques, the median number of segments with plaque per patient was one. Echocardiography was normal in 4/22 patients based on normal global longitudinal strain (GLS) and normal wall motion score index (WMSI); 4/22 patients had normal GLS with pathological WMSI; 3/22 patients had pathological GLS and normal WMSI; 11/22 patients had pathological GLS and WMSI and among them we could identify 5 patients with a Takotsubo pattern on echo.

Conclusions

Despite a diagnosis of AMI, 80 % of patients with normal ICA showed no coronary plaques on CTCA. The remaining 20 % had only minimal non-obstructive atherosclerosis. Patients fulfilling clinical criteria for AMI but with completely normal ICA need further evaluation, suggestively with magnetic resonance imaging (MRI).

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0254-y) contains supplementary material, which is available to authorized users.

Smoking status and life expectancy after acute myocardial infarction in the elderly

OBJECTIVE

Smokers have lower short-term mortality after acute myocardial infarction (AMI) than non-smokers; however, little is known about the long-term effects of smoking on life expectancy after AMI. This study aimed to quantify the burden of smoking after AMI using life expectancy and years of life lost.

METHODS

We analysed data from the Cooperative Cardiovascular Project, a medical record study of 158,349 elderly Medicare patients with AMI and over 17 years of follow-up, to evaluate the age-specific association of smoking with life expectancy and years of life lost after AMI.

RESULTS

Our sample included 23,447 (14.8%) current smokers. Current smokers had lower crude mortality up to 5 years, which was largely explained by their younger age at AMI. After adjustment other patient characteristics, smoking was associated with lower 30-day (HR 0.91, 95% CI 0.87 to 0.94) but higher long-term mortality (17-year HR 1.19, 95% CI 1.17 to 1.20) after AMI. Overall, crude life expectancy estimates were lower for current smokers than non-smokers at all ages, which translated into sizeable numbers of life-years lost attributable to smoking. As age at AMI increased, the magnitude of life-years lost due to smoking decreased. After full risk adjustment, the differences in life expectancy between current smokers and non-smokers persisted at all ages.

CONCLUSIONS

Current smoking is associated with lower life expectancy and large numbers of life-years lost after AMI. Our findings lend additional support to smoking cessation efforts after AMI.

Cigarette smoking is associated with dose-dependent adverse effects on paraoxonase activity and fibrinogen in young women

CONTEXT

Smoking is associated with increased fibrinogen and decreased paraoxonase (PON) activity, markers of inflammation and oxidative stress, in patients with coronary artery disease.

OBJECTIVE

We tested the hypothesis that the adverse effect of smoking on these biomarkers of inflammation and oxidative stress would be detectable in otherwise healthy young female habitual smokers.

MATERIALS AND METHODS

Thirty-eight young women participated in the study (n = 20 habitual smokers, n = 18 non-smokers). Fibrinogen, PON-1 activity and HDL oxidant index (HOI) were measured.

RESULTS

Mean values of fibrinogen, PON-1 activity and log HOI were not different between the groups. Importantly, however, decreased PON-1 activity (rs = -0.51, p = 0.03) and increased fibrinogen (rs = 0.49, p = 0.04) were significantly correlated with increasing number of cigarettes smoked per day in habitual smokers.

DISCUSSION AND CONCLUSION

Cigarette smoking is associated with a dose-dependent adverse effect on PON-1 activity and fibrinogen in young women, which may have implications for future cardiovascular risk.

Adverse effects of cigarette and noncigarette smoke exposure on the autonomic nervous system: mechanisms and implications for cardiovascular risk

This review summarizes the detrimental effects of cigarette and noncigarette emission exposure on autonomic function, with particular emphasis on the mechanisms of acute and chronic modulation of the sympathetic nervous system. We propose that the nicotine and fine particulate matter in tobacco smoke lead to increased sympathetic nerve activity, which becomes persistent via a positive feedback loop between sympathetic nerve activity and reactive oxidative species. Furthermore, we propose that baroreflex suppression of sympathetic activation is attenuated in habitual smokers; that is, the baroreflex plays a permissive role, allowing sympathoexcitation to occur without restraint in the setting of increased pressor response. This model is also applicable to other nontobacco cigarette emission exposures (e.g., marijuana, waterpipes [hookahs], electronic cigarettes, and even air pollution). Fortunately, emerging data suggest that baroreflex sensitivity and autonomic function may be restored after smoking cessation, providing further evidence in support of the health benefits of smoking cessation.

Traditional risk factors and a Genetic Risk Score are associated with age of first acute coronary syndrome

OBJECTIVE

To examine the association between traditional risk factors (TRF) and a Genetic Risk Score (GRS) with age of first acute coronary syndrome (ACS). Early onset ACS may occur due to a high burden of TRFs or to genetic factors that accelerate atherosclerosis. Whether recently discovered genetic variants for ACS are more prevalent at earlier age of first ACS remains unknown.

METHODS

To construct a multilocus GRS, participants were genotyped for 30 single nucleotide polymorphisms (SNP) identified from prior genome-wide association studies. Linear regression models were fit to estimate the association between TRFs and GRS with age of first ACS.

RESULTS

We included 460 participants with a first ACS enrolled in the Recurrence and Inflammation in the Acute Coronary Syndromes (RISCA) cohort. Several TRFs were associated (all p<0.05) with earlier age of first ACS: male sex (6.9 years earlier (95% CI 4.1 to 9.7)), current cigarette smoking (8.1 years (95% CI 6.1 to 10.0)), overweight (Body Mass Index, BMI >25) and obesity (BMI>30) (5.2 years (95% CI 2.6 to 7.9)). In women, hormone replacement therapy was also associated with earlier age of first ACS (4.8 years earlier (95% CI 0.3 to 8.4)). After multivariable adjustment for TRFs, a 1 SD increment in the GRS was associated with a 1.0 (95% CI 0.1 to 2.0) year earlier age of first ACS.

CONCLUSIONS

Among individuals with a first ACS, a GRS composed of 30 SNPs is associated with younger age of presentation. Although genetic predisposition modestly contributes to earlier ACS, a heavy burden of TRF is associated with markedly earlier ACS.

Implications of changing definitions of myocardial infarction on number of events and all-cause mortality: the WHO 1979, ESC/ACC 2000, AHA 2003, and Universal 2007 definitions revisited

PURPOSE

To analyse the impact of four different definitions of acute myocardial infarction (AMI) on number of events and all-cause mortality after AMI.

METHODS

We retrospectively examined number of AMI events and mortality according to four different definitions of AMI, among 1494 patients admitted to Haukeland University Hospital in Norway from March 2002 to February 2003. Eligible for analysis were 815 patients with a discharge diagnosis of an AMI, and 679 patients without any AMI discharge diagnosis but with elevated cardiac troponin I level during admission.

RESULTS

Applying the WHO 1979 definition resulted in 566 definite AMIs among the 1494 patients and was used as reference. According to the other definitions, there were 455 (-20%) definite AMIs by the original troponin 'rise and fall' version of the ESC/ACC 2000 definition, 729 (+29%) by the troponin 'rise or fall' interpretation of the ESC/ACC 2000 definition, 761 (+34%) by the AHA 2003 definition, and 743 (+31%) by the Universal 2007 definition (all p < 0.001). The 28-day, 1-year, 5-year, and 8-year mortality for definite AMI applying the WHO 1979 definition was 12, 19, 32, and 40%, whereas applying the Universal 2007 definition resulted in a mortality of 14, 21, 35, and 43%, respectively.

CONCLUSIONS

The change of definitions of AMI during the last decades has had a significant impact on the number of AMI events and a moderate impact on the AMI mortality among hospitalized patients.

Reduction in cardiovascular risk using proactive multifactorial intervention versus usual care in younger (< 65 years) and older (≥ 65 years) patients in the CRUCIAL trial

OBJECTIVE

To compare the reduction in calculated Framingham 10 year coronary heart disease (CHD) risk after 52 weeks' intervention with a proactive multifactorial intervention (PMI) strategy (based on single-pill amlodipine/atorvastatin [SPAA]) versus continuing usual care (UC) (based on investigators' best clinical judgment) among younger (<65 years) and older (≥ 65 years) patients.

RESEARCH DESIGN AND METHODS

Sub-analysis of the Cluster Randomized Usual Care versus Caduet Investigation Assessing Long-term risk (CRUCIAL) trial. Eligible patients had hypertension and ≥ 3 cardiovascular risk factors.

MAIN OUTCOME MEASURE

Treatment-related reduction in calculated Framingham 10 year CHD risk between baseline and Week 52 in younger and older patients.

RESULTS

Nine hundred patients (63.5%) were <65 years (mean age 54.2 years, 57.4% men) and 517 patients (36.5%) were ≥ 65 years (mean age 70.5 years, 42.7% men). Younger patients had lower mean baseline CHD risk versus older patients (17.1% vs. 22.6%). A greater reduction in calculated CHD risk at Week 52 was observed in the PMI versus the UC arm in both younger (-33.2% vs. -2.9%, p < 0.001) and older (-32.7% vs. -5.7%, p < 0.001) patients. Least-squares mean treatment differences (PMI vs. UC) in percentage change from baseline in calculated CHD risk were similar in younger and older patients (-26.3% vs. -25.7%, age interaction p = 0.887). CHD risk reduction was slightly greater among younger men than younger women (-29.3 vs. -23.9, gender interaction p = 0.062). A low proportion of patients discontinued the PMI strategy due to adverse events in both age groups (5.8% vs. 6.1%, respectively). Study limitations included ad-hoc (not pre-specified) sub-group analysis and short duration of follow-up.

CONCLUSIONS

The PMI strategy based on the inclusion of SPAA in the treatment regimen is more effective than UC in reducing calculated CHD risk. This strategy may be considered as the treatment of choice in younger and older hypertensive patients with additional cardiovascular risk factors.