Governments could help prevent chronic obstructive pulmonary disease (COPD) by reducing smoking rates; for example, through tobacco sale restriction, increasing tobacco prices, reducing nicotine content, and banning smoking in public areas and workplaces. Smoking cessation in general, and in particular among patients with COPD, could be achieved through specific programs, including behavior modification and the use of nicotine replacement therapy, bupropion, or varenicline. Prevention and/or slowed COPD progression could be achieved by occupational exposure prevention; improved indoor/outdoor air quality; reduced cooking and heating pollutants; use of better stoves and chimneys, and alternative energy sources; and influenza and pneumococcal vaccination.
Key points
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Chronic obstructive pulmonary disease (COPD) is the pulmonary manifestation of multimorbidity caused by genetic susceptibility and interaction of environmental factors.
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COPD and multimorbidity are mainly caused by smoking/pollutants, unhealthy life style, and/or early events.
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The most important preventive interventions are smoking cessation and influenza and pneumococcal vaccination.
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Primary prevention may reduce the incidence and progression of COPD.
Introduction
Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. In 2017, COPD was responsible for 3.2 million deaths, which is expected to reach an annual rate of 4.4 million by 2040. COPD has a worldwide prevalence of 10.1% and afflicts individuals across low-income, middle-income, and high-income countries. Further, the rate of years of life lost prematurely increased by 13.2% between 2007 and 2017. ,
For a long time, COPD has been internationally recognized as a preventable condition given the significant role played by environmental/nongenetic factors in the initiation and development of most of its clinical phenotypes. This article details the characteristics and relationships among these varying and heterogeneous preventable traits. In the latest GOLD (Global Initiative for Chronic Obstructive Lung Disease) version, COPD is defined as “A common, preventable, and treatable disease characterized by persistent respiratory symptoms and airflow limitation, which result from airway and/or alveolar abnormalities usually caused by significant exposure to noxious particles or gases and influenced by host factors, including abnormal lung development. Comorbidities might have a significant impact on morbidity and mortality.”
Prevention is usually classified as primal, primary, secondary, and tertiary ( Table 1 ). Because current literature on COPD pathogenesis mainly discusses cigarette smoking and, to a lesser extent, exposure to outdoor, indoor, and occupational pollutants, this article primarily discusses the prevention, and particularly primary prevention.
| Definition | |
|---|---|
| Primal or primordial prevention | Any measure designed to help future parents provide their upcoming child with adequate attention, as well as secure physical and affective environments, from conception to the first birthday. Primordial prevention refers to measures designed to avoid initial early-life development of risk factors |
| Primary prevention | Measures for preventing disease establishment by eliminating disease causes or increasing resistance to disease. These measures include maintaining a healthy lifestyle, diet, and exercise regimen; avoiding smoking through prevention or cessation; and immunization against disease |
| Secondary prevention | Measures for preventing the disease from being symptomatic; for example, through blood pressure screening for hypertension (a risk factor for many cardiovascular diseases) and cancer screening |
| Tertiary prevention | Measures for reducing the harm of the disease, including symptoms, exacerbations, disability, or death, through treatment and rehabilitation |
General Chronic Obstructive Pulmonary Disease Prevention Concepts
The most recently updated consensus document and review articles on COPD , indicate primary prevention as the most important and effective intervention for COPD development. However, they have limited discussions on primary prevention compared with those on tertiary prevention; that is, pharmacologic treatment and prevention of exacerbations, as well as self-management. This limitation could be attributed to the limited evidence on primary prevention compared with that of other treatments; specifically, pharmacologic treatment.
In general, the most important approach for preventing COPD and chronic diseases is the primary prevention of the most important risk factor; specifically, but not exclusively for COPD, cigarette smoking. This approach has been indicated by the decreased mortality from smoking-induced diseases that have been associated with reduced smoking prevalence in the United States ( www.healthdata.org/data-visualization/tobacco-visualization ). However, although global estimates show a significant reduction in the prevalence of smoking between 1980 and 2012, the total number of smokers has increased in the same period from 721 million to 967 million, with a burden attributable to cigarette smoking exposure and secondhand smoking of 6.3 million deaths annually and 6.3% of disability-adjusted life-years. ,
Moreover, preventing environmental, indoor, and occupational exposure, even in childhood, is important, which has been indicated by improved lung function in children from regions with reduced ambient pollution. Previous studies have suggested that simple changes in cooking and heating methods, as well as in-house ventilation, in regions with indoor biomass use could improve lung health and reduce the COPD incidence. Although the cause-effect relationship between cigarette smoking and COPD is well established, the relationship between other pollutants and COPD is supported by much weaker evidence. In general, the strategy for COPD prevention is similar to that of all chronic diseases involving chronic multimorbidity, which is currently and increasingly the most important epidemic of the millennium. In this context, appropriate vaccination (influenza and pneumococcal vaccines) plays an essential role because this has been associated with positive outcomes not only in COPD but in all chronic diseases. ,
Primal and primary prevention
Currently available knowledge could be used to prevent and control chronic diseases, particularly COPD, which is likely both effective and cost-effective. Several approaches have been recommended for implementation of primal and primary prevention.
Developmental Origins of Adult Chronic Diseases
Multiple longitudinal cohort studies have suggested that the origins of some chronic diseases, including asthma and COPD, could begin before and shortly after birth. Impaired lung function has been documented in infancy, with evidence indicating that this altered lung function trajectory remains well into adulthood. Further, reduced lung function in childhood predisposes the individual to accelerated lung function deterioration and COPD later in life. Evidence relevant to both asthma and COPD indicates that early-life events, including environmental exposures, could alter the development of both immune function and lung mechanics, including lung injury and repair. , This finding indicates that primary prevention of chronic obstructive respiratory diseases should be initiated before conception and continued during pregnancy and the first years of life.
Maternal smoking, particularly in the early stages of pregnancy (<27 weeks), premature birth with or without associated bronchopulmonary dysplasia development, and maternal malnutrition are among the most important early risk factors for lower lung function in later life. Several longitudinal studies have reported that children with early-life lower respiratory tract illnesses are at an increased risk for subsequent chronic respiratory symptoms and forced expiratory volume in 1 second impairment, which often persist into adulthood. This finding is particularly true for pneumonia, which is mostly caused by viruses; specifically, respiratory syncytial virus infections and viral bronchiolitis obliterans. Therefore, prevention of prematurity and bronchopulmonary dysplasia, as well as the implementation of effective vaccinations and prevention strategies for childhood asthma, could help decrease the COPD risk. Similarly, efforts toward decreasing adolescent smoking and exposure to smoking, as well as environmental and indoor pollutants, during pregnancy and childhood could decrease the incidence of COPD.
Maternal Nutrition
Maternal nutrition is a potential risk factor for respiratory disease. Given that diet is modifiable, it provides an appealing approach for prevention strategies. Although there have been extensive studies on the impact of diet on asthma development with controversial results, the relationship between diet and COPD is more difficult to study because of the long natural history of the disease. Thus, most of what is known rests on circumstantial evidence. Theoretically, the consumption of diets with antioxidants during adulthood might prevent the oxidant damage involved in COPD development. However, the current reality is that, despite the prenatal period being a potentially critical development window, where interventions could contribute to the development of a healthy respiratory system and reduce the susceptibility to chronic respiratory diseases occurring later in life, it has been poorly studied and there remains a need for further active research.
Primary Prevention: Lifestyle, Education, and Health Promotion
Physical activity
Physical inactivity is an important preventable trait of chronic diseases, including COPD. Receiving education regarding an active lifestyle and improved access to exercise facilities, as well as walking and cycling paths, could promote physical activity. Individuals can be encouraged to use stairs instead of lifts or escalators in public places through signs, posters, and music; however, this has been reported to have small and short-lived effects. ,
Advocacy
Various communication methods are available. They range from one-to-one conversations to mass media campaigns and are often more effective when applied together rather than individually. Common communication methods include information campaigns, publications, Web sites, press releases, lobbying, and peer-to-peer communication. Providing health education on cardiovascular and respiratory risk factors by broadcasting and print media has been reportedly to be cost-effective.
Community-based interventions
Integrated community-based programs aim to reach the general population, as well as high-risk and priority segments such as workplaces, recreational areas, and religious/health care settings. Moreover, they enable active community participation in health decision making and simultaneous use of community resources and health services, as well as coordination of different activities through partnerships and coalitions. Successful community-based interventions require cooperation among community organizations, policy makers, businesses, health providers, and community residents. The successful implementation of such interventions for chronic diseases in developed countries shows that they could have considerable potential in developing countries.
School-based interventions
School health programs could be an effective means of reducing risks in a large susceptible population, the behavior of whom could determine future risk for chronic diseases such as COPD. These programs include 4 basic components: health policies, education, supportive environments, and health services. They make use of physical education, nutrition instruction and food services, health promotion among school personnel, and community outreach. Many school health programs focus on preventing risk factors associated with leading causes of death, disease, and disability, including tobacco and alcohol use, as well as dietary practices, physical activity, and sexual behavior. The World Bank reported that school health programs are highly cost-effective. For example, the annual cost of school health programs was estimated to be US$0.03 and US$0.06 per capita in low-income and middle-income countries, respectively, with a resulting 0.1% and 0.4% reduction of future disease burden. ,
Primary Prevention: Environmental Interventions
Recently, Abramson and colleagues reviewed the role of outdoor, indoor, and workplace pollution as risk factors for chronic respiratory diseases, including COPD and asthma, as well as the related potential preventive measures.
Outdoor interventions
Outdoor air pollution is the result of a combination of primary sources, including wood and biomass smoke and vehicle exhaust, and secondary pollutants, including ozone (O 3 ) formed by atmospheric photochemical reactions. Monitored and regulated reference pollutants in many countries include particulate matter (PM 10 μm and PM 2.5 μm) and gaseous pollutants, including O 3 , oxides of nitrogen (NOx), sulfur dioxide (SO 2 ), and carbon monoxide (CO). There have been extensive studies on the health effects of air pollutants, and their relationship with asthma and COPD have been well established, with more limited evidence regarding the relationship between environmental pollution peaks and COPD/asthma exacerbations.
Primary prevention of the adverse effects of air pollution is mainly focused on developing ambient air quality guidelines. Although different approaches have been adopted across jurisdictions, legislated standards are typically based on environmental health risk assessment. In Dublin, banning the sale of coal reduced black smoke levels and was associated with significant reductions in both respiratory and cardiovascular deaths. Implementation of emission control measures by Chinese authorities dramatically improved the air quality in Beijing during the 2008 Olympic Games, which was associated with reduced respiratory inflammation among young adults. However, many countries have not enforced such standards. Secondary prevention measures include advising individuals with preexisting cardiac and respiratory diseases to avoid heavy outdoor exertion on high-pollution days.
Indoor interventions
Biomass fuel (BMF) is the primary source of cooking and/or heating fuel for nearly 2.4 billion individuals worldwide, with most being from low-income countries; further, women and children are the most highly exposed during cooking and other domestic activities. These countries have been reported to have higher levels of BMF air pollutants in homes than the corresponding levels in high-income countries. A meta-analysis of 15 observational studies reported a dose-response association between BMF and COPD development, which indicates the importance of BMF in primary COPD prevention. Further, there is recent evidence of decreased COPD incidence with improved cooking fuels, provision of support and instructions for installing household biogas digesters and kitchen ventilation, improving biomass stoves, and installing exhaust fans. However, similar to environmental pollution, there is no solid evidence of the association between indoor pollution and increased COPD risk.
Workplace interventions
Population studies have reported that 10% to 15% of the total COPD burden might be associated with workplace exposure. COPD prevention could be achieved through adequate control of harmful workplace exposure. The various specific COPD-related workplace exposures could be prevented by reducing work exposure to vapors, gases, dust, and fumes. It might be important to identify workers with rapidly declining lung function, irrespective of the specific exposure, through accurate annual lung function measures. Early identification of patients with COPD is important and should be considered for reducing causative exposures and to prevent further harm to the individual and other similarly exposed workers. This outcome can be achieved using a respiratory questionnaire, accurate lung function measurements, and controlling workplace exposure.
Primary Prevention: Tobacco Smoking
Health policy: laws, regulations, and price interventions
International laws and treaties, as well as national and local legislation, regulations, ordinances, and other legal frameworks, are fundamental elements of effective public health policy and practice. Therefore, they should be considered while developing large-scale strategies for preventable diseases. Historically, laws have played a crucial role in several great achievements in public health, including environmental control laws, warnings on cigarette packs, and other tobacco control measures. Current laws related to chronic diseases, particularly COPD, have been shown to be effective and crucial components of comprehensive prevention and control strategies. Banning smoking in public places, as well as tobacco product advertisement, has been shown to be very cost-effective. There has been extensive use of legal frameworks regarding tobacco control; however, the World Health Organization (WHO) Framework Convention on Tobacco Control remains the only global framework. More effective use of legislation and regulations could reduce the burden of chronic disease (particularly COPD) and protect the rights of individuals with chronic diseases. For example, reducing nicotine levels in cigarettes could substantially reduce the enormous burden of smoking-related diseases and mortality. A clear example of the importance of legislation for prevention is the recent tobacco bill passed in the United States, which increases the federal minimum age for buying cigarettes or other tobacco products (eg, e-cigarettes or other vaping products) from 18 to 21 years (The New York Times. Congress Approves Raising Age to 21 for E-Cigarette and Tobacco Sales, 19 December 2019).
Taxation policies could be used to reduce tobacco use and environmental exposure, as well as generate revenue for health promotion and disease prevention programs. Increasing the price of tobacco could encourage cessation from using tobacco products, prevent others from starting, and discourage relapsing of ex–tobacco users. A 10% price increase in tobacco products has been shown to reduce its demand by 3% to 5% in high-income countries and by 8% in low-income and middle-income countries, with young individuals and the poor being the most responsive to price changes.
Secondhand smoke
A recent systematic review indicated significant variations in the studies conducted worldwide dealing with the potential effects of secondhand smoking and the associated disease burden across countries/regions. The variations observed could be attributed to different exposure levels, types of cigarettes, and smoking patterns leading to insufficient evidence in many areas. Moreover, it highlighted relevant gaps in the data quality, which weakens any conclusions. This finding is consistent with the report by Burney and Amaral on the validity of the evidence regarding outdoor and indoor pollution, a field that has the same methodological problems.
Smoking cessation
Active tobacco smoking is the single major COPD cause in large parts of the world; additionally, it might also cause fixed airflow limitation in patients with chronic asthma. Smoking avoidance and cessation remain the only proven primary prevention strategy for chronic respiratory diseases, particularly COPD development. Primary prevention should seek to prevent smoking initiation and promote smoking cessation. The WHO adopted a firm position and plan to increase smoking cessation and prevention, which has been ratified by several countries, including the European Union. However, 25 years after its publication, there is still no solid evidence of any global reduction in cigarette consumption attributable to this convention ; therefore, this approach remains only hypothetically preventable.
Smoking cessation using multiple approaches has the greatest potential for influencing the natural history of COPD. Long-term quitting success rates of up to 25% can be achieved when individual approaches to smoking cessation and legislative smoking bans are instituted. These approaches are also effective not only at increasing the quitting rates but also in reducing harm from secondhand smoke exposure. In addition, smoking cessation reduces the decline rate of lung function in early COPD and reduces all-cause mortality. , Various pharmacologic and behavioral approaches to smoking cessation are currently available.
It remains unclear whether using electronic nicotine delivery systems (e-cigarettes) is an effective harm reduction strategy or a bridge to tobacco smoking among the youth. The Forum of International Respiratory Societies, which includes the International Union against Tuberculosis, issued a position statement calling for e-cigarette restriction or regulation. , In 2019, there was a lung-illness outbreak with deaths being associated with e-cigarette product use (devices, liquids, refill pods, and/or cartridges). Patients, mostly adolescents and young adults aged less than 35 years, often present with a history of using e-cigarettes or other vaping products, especially tetrahydrocannabinol (THC)-containing products. Although the epidemic peak seems to have ended, it has attracted a lot of attention from health authorities and will possibly lead to some legislative controls on e-cigarette sales and use. Taken together, current evidence indicates that e-cigarettes are not safe and, although they may be effective in improving smoking cessation rates, they are plagued by problems and are not a safe alternative to cigarette smoking. Recently, the European Respiratory Society released a position paper stating the reasons why it does not recommend any product that may damage the lungs and human health, and therefore strongly supports the implementation of the WHO position, which also regulates the use of novel cigarette substitutive products.
Pharmacotherapies for smoking cessation
There has been a recent review of smoking cessation strategies. Nicotine replacement therapy (nicotine gums, inhalers, nasal sprays, transdermal patches, sublingual tablets, or lozenges) reliably increase the long-term smoking abstinence rates. Moreover, varenicline, bupropion, and nortriptyline, all of which have a safe therapeutic profile, have been shown to increase long-term quit rates; however, they should always be part of a supportive intervention program, rather than being provided as the sole intervention for smoking cessation. Counseling delivered by physicians and other health professionals significantly increases the quitting rates compared with self-initiated strategies. Even brief (3-minute) counseling periods urging smokers to quit improve the smoking cessation rates. Moreover, financial incentive models for smoking cessation have been shown to be more effective at facilitating persistent smoking cessation rates at 6 months than usual care. Combining pharmacotherapy and behavioral support increases smoking cessation rates.
Vaccinations
Influenza
A recent Cochrane analysis on several randomized controlled trials (RCTs) concluded that inactivated vaccination of patients with COPD reduced influenza-induced exacerbations greater than or equal to 3 weeks after vaccination; further, the effect size was similar to that of previous observational studies. Coadministration of live attenuated virus with the inactivated vaccine did not confer additional benefit. GOLD recommends influenza vaccinations for all patients with COPD.
Pneumococcal
Although both the Centers for Disease Control and Prevention (CDC) and the GOLD acknowledge limited evidence stemming from the design and conduct of RCTs, they both recommend pneumococcal vaccination. In randomized, double-blind, placebo-controlled trial involving 84,496 adults 65 years of age or older, the 13-valent polysaccharide conjugate vaccine (PCV13) was effective in preventing vaccine-type pneumococcal, bacteremic, and nonbacteremic community-acquired pneumonia and vaccine-type invasive pneumococcal disease but not in preventing community-acquired pneumonia from any cause. CDC recommends that individuals aged from 19 to 64 years should routinely receive PCV13 and the 23-valent pneumococcal polysaccharide vaccine (PPSV23). GOLD recommends the aforementioned pneumococcal vaccinations for all patients aged greater than 65 years. Moreover, the PPSV23 is recommended for younger patients with COPD with significant comorbid conditions, including chronic heart or lung disease.
Secondary prevention
In 2016, the US Preventive Services Task Force recommended against screening asymptomatic adults for COPD using spirometry. GOLD has recommended case finding in symptomatic patients but not screening in asymptomatic populations. The aforementioned recommendations are based on the absence of any evidence that screening helps in preventing risk factors. Further, early diagnosis is not useful because there is currently no available treatment that prevents the progression of early mild COPD in symptomatic patients to more severe COPD. , Thus the issue of screening for COPD remains highly controversial. , However, case finding is paramount so that interventions designed to reduce disease progression can be implemented.
Tertiary prevention
Tertiary prevention refers to reducing symptoms, exacerbations, disability, or death through pharmacologic treatment and rehabilitation. As detailed earlier, smoking cessation remains the most effective treatment to improve symptoms, alter disease progression, and reduce mortality in actively smoking patients with COPD. A recent study reported that 2-year treatment with tiotropium in early mild to moderate COPD improved lung function and quality of life and reduced exacerbations and lung function decline. However, it remains unclear whether these findings indicate a treatment effect in the early natural history of COPD. There are similar ongoing bronchodilator studies on whether there is a pharmacologic treatment effect in symptomatic smokers without airflow limitation, a relevant patient population that might present another true early COPD or pre-COPD. ,
Summary
COPD is defined as a preventable condition given that environmental/nongenetic factors play a crucial role in the initiation and development of most of the disease’s clinical expressions, which are possibly related to several interconnected preventable traits. Most of the current evidence on COPD pathogenesis originates from cigarette smoking, and to a lesser extent exposure to outdoor, indoor, and occupational pollutants. Therefore, currently available evidence regarding prevention strategies, and particularly primary prevention, is mainly related to these preventable traits. Smoking cessation has the greatest capacity for influencing the natural history of COPD, and smoking avoidance and cessation remains the only proven primary prevention strategy for chronic respiratory diseases. However, even 25 years after the publications of the WHO regarding cigarette smoking, there is still no solid evidence indicating that this convention has globally reduced cigarette consumption. Primary prevention of adverse air pollution effects has been focused on developing ambient air quality guidelines; however, many countries have lacked in the enforcement of standards. BMF air pollutants measured in homes in low-income countries have been greater than the corresponding values in high-income countries, with evidence of a consistent dose-response relationship. Improving cooking fuels and kitchen ventilation could potentially be effective in decreasing COPD incidence in these conditions. However, although primary prevention remains fundamental for COPD and for all chronic diseases, the evidence of its feasibility and effectiveness remains weak. This weakness is emphasized by a National Institutes of Health (NIH) workshop report that provides a detailed list of future research/actions necessary to properly address this important issue ( Box 1 ).
