Light and noise pollution and socioeconomic status: the risk factors individuals cannot change

For the podcast associated with this article, please visit https://academic.oup.com/eurheartj/pages/Podcasts. This Focus Issue on epidemiology and prevention contains the Special Article ‘The year in cardiovascular medicine 2020: epidemiology and prevention’, authored by Ramon Estruch from the University of Barcelona in Spain, and colleagues.1 The authors note that cardiovascular disease (CVD) prevention has been classically divided into primary (aimed at asymptomatic subjects) and secondary (aimed at patients who have already suffered a cardiovascular event), but currently this classification is considered arbitrary given the overlap observed, for example in diabetic patients. Thus, prevention measures may be better divided into ‘prevention at the population level’ and ‘prevention strategies in subjects with high vascular risk’. In the current paper, the authors review relevant contributions to CVD prevention published in 2020. Estruch et al. have also included references to relevant articles related to cardio-renal syndrome and the common pathways of cancer and CVD, as well as new aspects of cardiac disease due to COVID-19 infection (Figure 1). Different components involved in the lifetime genesis and evolution of cardiovascular risk. The three most important messages are: first, the need to prevent an unhealthy environment; second, the need to maintain an adequate lifestyle; and third, the use of appropriate pharmacotherapy when required. The first two have to be maintained for the lifetime, while pharmacological treatment should be started at an earlier age than was recommended a few years ago. (from Estruch R, Ruilope LM, Cosentino F. The year in cardiovascular medicine 2020: epidemiology and prevention. See pages 813–821) Different components involved in the lifetime genesis and evolution of cardiovascular risk. The three most important messages are: first, the need to prevent an unhealthy environment; second, the need to maintain an adequate lifestyle; and third, the use of appropriate pharmacotherapy when required. The first two have to be maintained for the lifetime, while pharmacological treatment should be started at an earlier age than was recommended a few years ago. (from Estruch R, Ruilope LM, Cosentino F. The year in cardiovascular medicine 2020: epidemiology and prevention. See pages 813–821) Coronary heart disease (CHD) is a leading cause of death globally, responsible for >8.9 million deaths and 165 million disability-adjusted life years in 2017. While traditional risk factors account for a substantial proportion of CHD, the importance of environmental risk factors such as ambient air pollution and night-time noise is increasingly recognized.2–6 In a clinical research article entitled ‘Outdoor light at night and risk of coronary heart disease among older adults: a prospective cohort study’, Shengzhi Sun from the University School of Public Health in Boston, Massachusetts, USA and colleagues estimated the association between outdoor light at night at a person’s residence and risk of CHD within a prospective cohort of older adults in Hong Kong.7 Over a median of 11 years of follow-up, the authors identified 3772 incident CHD hospitalizations and 1695 CHD deaths. Annual levels of outdoor light at night at participants’ residential addresses were estimated using time-varying satellite data for a composite of persistent night-time illumination. The association between light at night and incident CHD hospitalization and mortality exhibited a monotonic exposure–response function. An interquartile range increase in outdoor light at night was associated with a hazard ratio of 1.11 [95% confidence interval (CI) 1.03–1.18] for CHD hospitalizations and 1.10 (95% CI 1.00–1.22) for CHD deaths after adjusting for both individual- and area-level risk factors. The association did not vary across strata of hypothesized risk factors. The authors conclude that among older adults, outdoor light at night at their residence is associated with a higher risk of CHD hospitalizations and deaths. They caution against causal interpretation of these novel findings. Future studies with more detailed information on exposure, individual adaptive behaviours, and potential mediators are warranted to further examine the relationship between light at night and CHD risk. The manuscript is accompanied by an Editorial by Thomas Münzel and colleagues from the University Medical Center Mainz in Germany.8 The authors note that currently, the public interest and efforts in addressing the health burden of environmental stressors have increased significantly and our societies are becoming more and more aware of the impact of the environment on health and disease. More effective policies and prevention strategies that adequately strengthen these efforts are needed to reduce the burden of disease imposed by environmental risk factors such as light, air, and noise pollution. A meta-analysis performed for the new WHO noise guidelines considered all studies published until 2015 and reported that the risk for CHD increases by 8% per 10 dB increase in long-term road traffic noise.9 While most epidemiological studies addressed cardiovascular effects of long-term exposure to transportation noise, there is a need to better understand whether noise exposure also acts as a trigger for cardiovascular events and how the timing of noise exposure modulates this response. Experimental studies have shown acute effects of environmental noise on different physiological responses, such as endothelial dysfunction, hypertension, and sleep quality.10,11 In a clinical research article entitled ‘Does night-time aircraft noise trigger mortality? A case-crossover study on 24 886 cardiovascular deaths’, Martin Röösli from the University of Basel in Switzerland, and colleagues note that it is unclear whether night-time noise events, including from airplanes, could trigger a cardiovascular death.12 In this study, the authors investigated the potential acute effects of aircraft noise on mortality and the specific role of different night-time exposure windows in 24 886 cases of death from CVD from the Swiss National Cohort around Zürich Airport between 2000 and 2015. For night-time deaths, exposure levels 2 h preceding death were significantly associated with mortality for all causes of CVD (odds ratio 1.44, 95% CI 1.03–2.04) for the highest exposure group. Most consistent associations were observed for CHD, myocardial infarction, heart failure, and arrhythmia. Associations were more pronounced for females and for people living in areas with low road and railway background noise and in buildings constructed before 1970. Röösli et al. conclude that their findings suggest that night-time aircraft noise can trigger acute cardiovascular mortality. The manuscript is accompanied by an Editorial by Andreas Daiber and colleagues from the University Medical Center Mainz in Germany.13 The authors note that the study by Röösli et al. describes for the first time acute effects of noise on cardiovascular mortality. They conclude that there is now substantial evidence that (aircraft) noise is a cardiovascular risk factor that cannot be modified by patients or doctors, but rather by politicians and cardiovascular societies reinforcing, for example, the new noise limits published in the WHO guidelines concerning road, aircraft, and railway noise. Atrial fibrillation (AF) is one of the most commonly diagnosed arrhythmias; however, data remain scarce regarding its epidemiology in Europe. Despite innovations in AF treatment, ranging from anticoagulation to ablation, previous studies have shown a global increase in AF-associated mortality in the last 20 years.14,15 In a clinical research article entitled ‘Paradoxical impact of socioeconomic factors on outcome of atrial fibrillation in Europe: trends in incidence and mortality from atrial fibrillation’, Becker Mushriq Al-khayatt from Saint George’s University Hospitals NHS Foundation Trust in London, UK, and colleagues aimed to understand the changing trends in AF incidence and mortality across Europe from 1990 to 2017, and how socioeconomic factors and sex differences play a role.16 The authors performed a temporal analysis of data from the 2017 Global Burden of Disease Database for 20 countries across Europe using Joinpoint regression analysis and present age-adjusted incidence, mortality, and mortality to incidence ratios (MIRs). Incidence and mortality trends were heterogenous throughout Europe. Mortality rates were higher in wealthier countries, with the highest being in Sweden for both men and women (8.83 and 8.88 per 100 000, respectively) in 2017. MIRs were higher in women in all studied countries, with the disparity increasing over time mostly in Germany. Graphical abstract. (from Agerström J, Carlsson M, Bremer A, Herlitz J, Israelsson J, Å restedt K. Discriminatory cardiac arrest care? Patients with low socioeconomic status receive delayed cardiopulmonary resuscitation and are less likely to survive an inhospital cardiac arrest. Pages 861–869) Graphical abstract. (from Agerström J, Carlsson M, Bremer A, Herlitz J, Israelsson J, Å restedt K. Discriminatory cardiac arrest care? Patients with low socioeconomic status receive delayed cardiopulmonary resuscitation and are less likely to survive an inhospital cardiac arrest. Pages 861–869) The authors conclude that their study identifies several key findings. First, the rates of change of incidence and mortality are heterogeneous throughout Europe, with some nations faring better than others over the 28 years studied, with a significantly higher mortality in countries above the mean European gross domestic product per capita. Secondly, mortality attributable to AF per case, or at least its approximation in the form of MIR, has not improved over time, and in many nations is actually increasing, despite apparent advances in AF care. Thirdly, MIRs are higher in women than in men in all countries studied, with some nations faring worse than others in terms of this sex disparity. The manuscript is accompanied by an Editorial by Isabelle Van Gelder from the University Medical Center Groningen in The Netherlands.17 In their commentary, the authors note that the study by Mushriq Al-khayatt and colleagues is a call for more research in individual European countries and more multinational studies including Western and Eastern European countries, as is currently done in the STEEER-AF and EHRA-PATHS trials. Individuals with low socioeconomic status (SES) face widespread prejudice in society. Patients with higher SES appear to be more likely to receive bystander cardiopulmonary resuscitation (CPR), which might partly explain the positive overall relationship between SES and survival after out-of-hospital cardiac arrest.18 Whether there are SES disparities in relation to in-hospital cardiac arrest (IHCA), however, is unclear. In a clinical research article entitled ‘Discriminatory cardiac arrest care? Patients with low socioeconomic status receive delayed cardiopulmonary resuscitation and are less likely to survive an in-hospital cardiac arrest’, Jens Agerströmv from the Linnaeus University in Kalmar/Växjö in Sweden, and colleagues examine SES disparities in IHCA treatment and survival, assessing SES at the patient level and adjusting for major demographic, clinical, and contextual factors.19 About 24 000 IHCAs from the Swedish Register of Cardiopulmonary Resuscitation were analysed. Education and income constituted SES proxies. Controlling for age, gender, ethnicity, comorbidity, heart rhythm, aetiology, hospital, and year, primary analyses showed that high (vs. low) SES patients were significantly less likely to receive delayed CPR. Furthermore, patients with high SES were significantly more likely to survive CPR, to survive to hospital discharge with good neurological outcome, and to survive to 30 days. Secondary analyses showed that patients with high SES were also significantly more likely to receive prophylactic heart rhythm monitoring, and this seems to partially explain the observed SES differences in CPR delay (Figure 2). Agerströmv and colleagues conclude that there are clear SES differences in IHCA treatment and survival, even when controlling for major sociodemographic, clinical, and contextual factors. This suggests that patients with low SES could be subject to discrimination when suffering IHCA. The manuscript is accompanied by an Editorial by Elias Mossialos and Sahan Jayawardana from the The London School of Economics and Political Science in the UK.20 The authors conclude that closing the gaps in life expectancy between different social groups in Europe—and world wide—will require us once more to align our economic and moral concerns and address the societal conditions that generate health disparities in the first place. The editors hope that this issue of the European Heart Journal will be of interest to its readers. With thanks to Amelia Meier-Batschelet, Johanna Huggler, and Martin Meyer for help with compilation of this article.