Smoking Status and Incidence of Cancer After Myocardial Infarction: A Follow-Up Study of over 20 Years

Cardiac surgery and long-term risk for incident cancer: A nationwide population-based study

OBJECTIVE

Previous studies indicate an increased long-term risk for incident cancer and cancer-specific mortality in patients undergoing cardiac surgery. We compared the risk for incident cancer and cancer-specific mortality between patients and matched control subjects from the general population.

METHODS

All patients (n = 127,119) undergoing first-time coronary artery or heart valve surgery in Sweden during 1997-2020 were included in a population-based observational cohort study based on individual data from the SWEDEHEART registry and 4 other mandatory national registries. The patients were compared with an age-, sex-, and place of residence-matched control population (n = 415,287) using multivariable Cox proportional hazards regression models adjusted for baseline characteristics, comorbidities, and socioeconomic factors. A propensity score-matched analysis with 81,522 well-balanced pairs was also performed.

RESULTS

Median follow-up was 9.2 (range, 0-24) years. A total of 31,361/127,119 patients (24.7%) and 102,959/415,287 control subjects (24.8%) developed cancer during follow-up. The crude event rates were 2.75 and 2.83 per 100 person-years, respectively. The adjusted risk for cancer and cancer-specific mortality was lower in patients (adjusted hazard ratios 0.86 [95% CI, 0.85-0.88] and 0.64 [95% CI, 0.62-0.65], respectively). The propensity score-matched analysis showed similar results (hazard ratios, 0.88 [95% CI, 0.86-0.90] and 0.65 [95% CI, 0.63-0.68], respectively). The results were consistent in subgroups based on sex, age, and comorbidities.

CONCLUSIONS

Patients who underwent cardiac surgery have lower risk for cancer and cancer-specific mortality than matched control subjects.

Changes in smoking use and subsequent lung cancer risk in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study

BACKGROUND

Reducing cigarettes per day may lower the risk of lung cancer compared with continuing to smoke at the same intensity. Other changes in smoking behaviors, such as increasing cigarette consumption or quitting for a period and relapsing, may also affect lung cancer risk.

METHODS

We examined changes in smoking status and cigarettes per day among 24 613 Finnish male smokers aged 50-69 years who participated in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Longitudinal data on smoking were collected during study follow-up visits 3 times a year (approximately every 4 months) between 1985 and 1993. Incident lung cancer patients through 2012 were identified by the Finnish Cancer Registry. Risk ratios (RRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression.

RESULTS

Compared with smoking 20 cigarettes per day continuously across the intervention period, reducing an average of 5 cigarettes per day per year while smoking was associated with a 20% lower risk of lung cancer (95% CI = 0.71 to 0.90). A substantially lower risk of lung cancer was also observed when participants smoked at 50% (RR = 0.72, 95% CI = 0.57 to 0.90) and 10% (RR = 0.55, 95% CI = 0.36 to 0.83) of study visits, relative to smoked at 100% of study visits.

CONCLUSIONS

Smokers may lower their risk of lung cancer by reducing smoking intensity (cigarettes per day while smoking) and the time they smoke. However, quitting smoking completely is the most effective way for smokers to reduce their risk of lung cancer.

Smoking cessation for secondary prevention of cardiovascular disease

BACKGROUND

Smoking is a leading cause of cardiovascular disease (CVD), particularly coronary heart disease (CHD). However, quitting smoking may prevent secondary CVD events in people already diagnosed with CHD.  OBJECTIVES: To examine the impact of smoking cessation on death from CVD and major adverse cardiovascular events (MACE), in people with incident CHD.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialised Register, CENTRAL, MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, and the trials registries clinicaltrials.gov and the International Clinical Trials Registry Platform. We ran all searches from database inception to 15 April 2021.  SELECTION CRITERIA: We included cohort studies, and both cluster- and individually randomised controlled trials of at least six months' duration. We treated all included studies as cohort studies and analysed them by smoking status at follow-up. Eligible studies had to recruit adults (> 18 years) with diagnosed CHD and who smoked tobacco at diagnosis, and assess whether they quit or continued smoking during the study. Studies had to measure at least one of our included outcomes with at least six months' follow-up. Our primary outcomes were death from CVD and MACE. Secondary outcomes included all-cause mortality, non-fatal myocardial infarction, non-fatal stroke, new-onset angina and change in quality of life.  DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methods for screening and data extraction.  We assessed the risk of bias for the primary outcomes using the ROBINS-I tool. We compared the incidence of death from CVD and of MACE (primary outcomes) between participants who quit smoking versus those who continued to smoke for each included study that reported these outcomes. We also assessed differences in all-cause mortality, incidence of non-fatal myocardial infarction, incidence of non-fatal stroke and new onset angina. We calculated hazard ratios (HRs) and 95% confidence intervals (95% CI). For our outcome, change in quality of life, we calculated the pooled standardised mean difference (SMD) and 95% CI for the difference in change in quality of life from baseline to follow-up between those who had quit smoking and those who had continued to smoke. For all meta-analyses we used a generic inverse variance random-effects model and quantified statistical heterogeneity using the I²statistic. We assessed the certainty of evidence for our primary outcomes using the eight GRADE considerations relevant to non-randomised studies.

MAIN RESULTS

We included 68 studies, consisting of 80,702 participants. For both primary outcomes, smoking cessation was associated with a decreased risk compared with continuous smoking: CVD death (HR 0.61, 95% CI 0.49 to 0.75; I² = 62%; 18 studies, 17,982 participants; moderate-certainty evidence) and MACE (HR 0.57, 95% CI 0.45 to 0.71; I² = 84%; 15 studies, 20,290 participants; low-certainty evidence). These findings were robust to our planned sensitivity analyses. Through subgroup analysis, for example comparing adjusted versus non-adjusted estimates, we found no evidence of differences in the effect size. While there was substantial heterogeneity, this was primarily in magnitude rather than the direction of the effect estimates. Overall, we judged 11 (16%) studies to be at moderate risk of bias and 18 (26%) at serious risk, primarily due to possible confounding. There was also some evidence of funnel plot asymmetry for MACE outcomes. For these reasons, we rated our certainty in the estimates for CVD death as moderate and MACE as low.  For our secondary outcomes, smoking cessation was associated with a decreased risk in all-cause mortality (HR 0.60, 95% CI 0.55 to 0.66; I² = 58%; 48 studies, 59,354 participants), non-fatal myocardial infarction (HR 0.64, 95% CI 0.58 to 0.72; I² = 2%; 24 studies, 23,264 participants) and non-fatal stroke (HR 0.70, 95% CI 0.53 to 0.90; I² = 0%; 9 studies, 11,352 participants). As only one study reported new onset of angina, we did not conduct meta-analysis, but this study reported a lower risk in people who stopped smoking. Quitting smoking was not associated with a worsening of quality of life and suggested improvement in quality of life, with the lower bound of the CI also consistent with no difference (SMD 0.12, 95% CI 0.01 to 0.24; I² = 48%; 8 studies, 3182 participants).  AUTHORS' CONCLUSIONS: There is moderate-certainty evidence that smoking cessation is associated with a reduction of approximately one-third in the risk of recurrent cardiovascular disease in people who stop smoking at diagnosis. This association may be causal, based on the link between smoking cessation and restoration of endothelial and platelet function, where dysfunction of both can result in increased likelihood of CVD events.  Our results provide evidence that there is a decreased risk of secondary CVD events in those who quit smoking compared with those who continue, and that there is a suggested improvement in quality of life as a result of quitting smoking. Additional studies that account for confounding, such as use of secondary CVD prevention medication, would strengthen the evidence in this area.

Dissatisfaction with Married Life in Men Is Related to Increased Stroke and All-Cause Mortality

The objectives of this study were to assess the association between marital satisfaction and specific and all-cause mortality, and to examine whether this association is independent of other known risk factors for early mortality. In this prospective cohort, male Israeli civil servants and municipal employees (n = 8945) underwent an extensive appraisal of health and behavioral patterns and were followed for more than three decades. Cox proportional hazards analysis was used to estimate the relative risks for stroke and all-cause mortality over time across marital satisfaction categories. During the 32 years of follow-up, 5736 (64.1%) died. Dissatisfaction with married life was related to increased long-term risk of stroke (HR = 1.94; 95%CI, 1.41–2.90) and all-cause mortality (HR = 1.21; 95%CI, 1.04–1.41). The latter association was of a similar order of magnitude to other known risk factors for early mortality, such as people with a history of smoking (HR = 1.37; 95%CI, 1.30–1.48) compared to people who have never smoked and for physically inactive participants (HR = 1.21; 95%CI, 1.14–1.37) compared to physically active participants. The results of our study suggest that marital dissatisfaction may predict an elevated risk of all-cause mortality. Assessing marital satisfaction and measuring the health benefits of marital education programs for couples should be implemented as part of health promotion strategies for the general population.

Cigarette Smoking Reduction and Health Risks: A Systematic Review and Meta-analysis

Introduction

Studies have shown the health benefits of cigarette smoking cessation. However, the literature remains unclear about the relationship between smoking reduction and health risks. This comprehensive review and meta-analysis updates previous reviews with the newest estimates.

Aims and Methods

We conducted a systematic review and meta-analysis evaluating the association between smoking reduction and some health risks in observational studies. We defined the following smoking categories: heavy smokers smoked ≥15–20 cigarettes per day (CPD), moderate smokers smoked 10–19 CPD, and light smokers smoked <10 CPD. The relative risks (RRs) and 95% confidence intervals (CIs) were estimated using random-effect models.

Results

We identified 19 studies including four case–control and 15 cohort studies. Compared with continuing heavy smokers, we found decreased lung cancer risk for those who reduced CPD by more than 50% (RR = 0.72, 95% CI: 0.52, 0.91), from heavy to moderate (RR = 0.66, 95% CI: 0.46, 0.85), and from heavy to light (RR = 0.60, 95% CI: 0.49, 0.72). We also found lower risk of cardiovascular disease (CVD) for those who reduced from heavy to light smoking (RR = 0.78, 95% CI: 0.67, 0.89) but not those who reduced by more than 50% and reduced smoking from heavy to moderate. We did not find any significant difference in all-cause mortality, all-cancer risks, and smoking-/tobacco-related cancer risk among those who reduced.

Conclusions

Substantial smoking reduction may decrease lung cancer risk but results on CVD (coronary heart disease and stroke combined) risk were mixed. The relationships between smoking reduction and other endpoints examined were not significant.

Implications

This meta-analysis helps clarify our understanding of various smoking reduction levels on some health risks. While smoking reduction may decrease risks of lung cancer, the relationships between smoking reduction and other endpoints, including all-cause mortality and cardiovascular disease, remain unclear. Although smoking reduction may decrease lung cancer risks, the magnitude of lung cancer risk remain high. Among smokers, complete cessation remains the most effective approach for cancer and CVD prevention.

Abnormal ankle-brachial index (ABI) predicts primary and secondary cardiovascular risk and cancer mortality

BACKGROUND

An abnormal ankle-brachial pressure index (ABI) is a marker of the risk for increased total and cardiovascular (CV) mortality. However, it is not clear whether it is associated with an even worse prognosis in patients with previous CV events or with cancer mortality.

MATERIALS AND METHODS

Consecutive subjects undergoing ABI assessment for suspected peripheral artery disease or for stratification of CV risk in ten centers in the Veneto Region (northeast Italy), between 2011 and 2014 were enrolled. The ABI was expressed as normal ≥0.9 to ≤1.3, and abnormal <0.9 or >1.3. All-cause mortality and CV or cancer mortality and hospitalizations for CV disease were collected from administrative databases up to December 2018.

RESULTS

The study enrolled 1,177 patients. ABI was abnormal in 57.2%. Median follow-up was 61.6 months (53.4-70.1). All-cause, CV and cancer mortality were higher in patients with abnormal than normal ABI, with hazard ratios (HR) respectively 2.0 (95% CI 1.48-2.69), 1.98 (95% CI 1.24-3.17) and 1.85 (95% CI 1.09-3.15). Among subjects with abnormal ABI, the risk of overall mortality, HR 1.57 (95% CI 1.17-2.12), and CV mortality, HR 2.39 (95% CI 1.43-3.99), was higher in those with previous CV events. These latter also had a higher risk of hospitalization for myocardial infarction and stroke: HR 1.85 (95% CI 1.023.37) and 2.17 (95% CI 1.10-4.28).

CONCLUSIONS

The co-existence of abnormal ABI and a history of CV events identifies subjects at higher risk, who call for a more aggressive approach. Abnormal ABI is also a predictor of cancer mortality.

Common risk factors for heart failure and cancer

Cardiovascular (CV) disease and cancer are the leading causes of death.1,2 Over the last decades, it has been appreciated that both CV disease and cancer are more common in individuals in whom risk factors for disease development accumulate, and preventative measures have been extremely important in driving down the incidence of disease.3-6 In general, the field of epidemiology, risk reduction, and preventative trials is divided into health care professionals who have an interest in either CV disease or cancer. As a result, the medical literature and medical practice has largely focused on the one disease, or the other. However, human individuals do not behave according to this dogma. Emerging data clearly suggest that identical risk factors may lead to CV disease in the one individual, but may cause cancer in another, or even both diseases in the same individual. This overlap exists between risk factors that are historically classified as 'CV risk factors' as these factors do equally strong predict cancer development. Therefore, we propose that a holistic approach might better estimate actual risks for CV disease and cancer. In this review, we summarize current insights in common behavioural risk factors for heart failure, being the most progressed and lethal form of CV disease, and cancer.