Chronic respiratory diseases: a global view
Authors: Wassim W Labaki, MeiLan K Han
Journal: The Lancet Respiratory Medicine (2020)

Chronic respiratory diseases are among the most common non-communicable diseases worldwide, largely due to the ubiquity of noxious environmental, occupational, and behavioural inhalational exposures.1James SL Abate D Abate KH et al.Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017.Lancet. 2018; 392: 1789-1858Summary Full Text Full Text PDF PubMed Scopus (3033) Google Scholar In addition to chronic obstructive pulmonary disease (COPD) and asthma, chronic respiratory diseases include interstitial lung disease, pulmonary sarcoidosis, and pneumoconioses, such as silicosis and asbestosis. Unfortunately, chronic respiratory diseases have received proportionately less public attention and less research funding than other disease entities such as cardiovascular disease, cancer, stroke, diabetes, and Alzheimer's disease.2Boehm A Pizzini A Sonnweber T et al.Assessing global COPD awareness with Google Trends.Eur Respir J. 2019; 531900351Crossref PubMed Scopus (17) Google Scholar, 3Gross CP Anderson GF Powe NR The relation between funding by the National Institutes of Health and the burden of disease.N Engl J Med. 1999; 340: 1881-1887Crossref PubMed Scopus (357) Google Scholar Therefore, to better inform prevention, screening, treatment, and research efforts dedicated to chronic respiratory diseases, it is crucial to understand their prevalence, morbidity, and mortality, both on global and regional scales. In The Lancet Respiratory Medicine, Joan Soriano and colleagues leverage the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 to estimate the prevalence and attributable health burden of chronic respiratory diseases.4Soriano JB Kendrick P Paulson K Gupta V Vos T Prevalence and attributable health burden of chronic respiratory diseases, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017.Lancet Respir Med. 2020; 8: 585-596Google Scholar They found that close to 545 million people in the world had a chronic respiratory disease in 2017, an increase of 39·8% since 1990. The high-income super-region had the highest prevalence of chronic respiratory diseases, while south Asia and sub-Saharan Africa had, somewhat surprisingly, the lowest prevalence. The most prevalent chronic respiratory diseases were COPD (3·9% global prevalence) and asthma (3·6%). Chronic respiratory diseases accounted for 3·9 million deaths in 2017 (an increase of 18·0% since 1990) and were responsible for 1470 disability-adjusted life-years (DALYs) per 100 000 individuals (112·3 million total DALYs, an increase of 13·3% since 1990). South Asia had the highest mortality attributable to chronic respiratory disease, while sub-Saharan Africa had the lowest. COPD and asthma were the top causes of chronic respiratory disease-related deaths worldwide, but interstitial lung disease and pulmonary sarcoidosis were the second leading cause of death in the high-income, Latin America and the Caribbean, and central Europe, eastern Europe, and central Asia super-regions. Although the absolute estimates of the prevalence and health burden of chronic respiratory diseases increased between 1990 and 2017, there were decreases in age-standardised estimates of prevalence (−14·3%), mortality (−42·6%), and DALYs (−38·2%) in the same period. Smoking accounted for the highest proportion of disability attributable to chronic respiratory disease in all regions for men. However, for women, the leading risk factor for disability varied by region: household air pollution from solid fuel use in south Asia and sub-Saharan Africa, exposure to ambient particulate matter in the southeast Asia, east Asia, and Oceania and the north Africa and Middle East super-regions, and smoking in all other super-regions. These findings not only confirm that chronic respiratory diseases are common and are associated with substantial morbidity and mortality, but also highlight the heterogeneity of chronic respiratory disease-related health burden and risk factors by world region and sex. However, some of these estimates should be interpreted with caution. For example, the lower prevalence of chronic respiratory diseases in south Asia and sub-Saharan Africa might be due to underdiagnosis in settings that lack or underutilise diagnostic capabilities.5Vanjare N Chhowala S Madas S Kodgule R Gogtay J Salvi S Use of spirometry among chest physicians and primary care physicians in India.NPJ Prim Care Respir Med. 2016; 2616036Crossref PubMed Scopus (15) Google Scholar Furthermore, lower mortality in sub-Saharan Africa than in other regions could reflect differences in the age distribution of the population towards younger individuals, in whom deaths from communicable diseases occur in greater frequency than do deaths from chronic diseases.6Institute for Health Metrics and EvaluationGBD Compare—Viz Hub.https://vizhub.healthdata.org/gbd-compare/Date accessed: March 12, 2020Google Scholar In addition, imperfect clinical case definitions probably affect the accuracy of some of the reported figures. For instance, a non-negligible number of individuals between the ages of 5 years and 24 years are reported as having COPD, which would be unexpected, even when taking into account the possible contribution of α-1-antitrypsin deficiency. Despite these limitations, this study provides an important framework to spur much needed action to address the growing burden of chronic respiratory diseases worldwide. First, ramping up global, regional, and local tobacco and pollution control measures is paramount. A separate GBD report showed that levels of ambient particulate matter pollution, ambient ozone pollution, and several occupational exposures have increased significantly between 1990 and 2017.7Stanaway JD Afshin A Gakidou E et al.Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017.Lancet. 2018; 392: 1923-1994Summary Full Text Full Text PDF PubMed Scopus (1438) Google Scholar In addition, many countries are still facing rising smoking epidemics, especially among women and adolescents.8Wang M Luo X Xu S et al.Trends in smoking prevalence and implication for chronic diseases in China: serial national cross-sectional surveys from 2003 to 2013.Lancet Respir Med. 2019; 7: 35-45Summary Full Text Full Text PDF PubMed Scopus (80) Google Scholar Second, efforts should be deployed to promote early diagnosis and treatment of chronic respiratory diseases with the goal of improving long-term clinical outcomes, including premature mortality. A substantial number of individuals living with a chronic respiratory disease remain, unfortunately, undiagnosed, even in developed countries.9Martinez CH Mannino DM Jaimes FA et al.Undiagnosed obstructive lung disease in the United States: associated factors and long-term mortality.Ann Am Thorac Soc. 2015; 12: 1788-1795Crossref PubMed Scopus (86) Google Scholar Timely detection of chronic respiratory diseases requires adequate access to and use of diagnostic instruments such as spirometry and chest imaging, but also effective and practical case-finding approaches.10Labaki WW Han MK Improving detection of early chronic obstructive pulmonary disease.Ann Am Thorac Soc. 2018; 15: S243-S248Crossref PubMed Scopus (12) Google Scholar Third, increasing research funding is essential to develop strategies to detect chronic respiratory diseases at their earliest stage and to accelerate the discovery of novel therapies, which are sorely needed for many of these diseases. As an example of funding disparity, cannabis-related research received US$220 million in US National Institutes of Health funding in 2019, in contrast to $112 million for COPD research.11National Institutes of HealthEstimates of funding for various research, condition, and disease categories (RCDC).https://report.nih.gov/categorical_spending.aspxDate: Feb 24, 2020Date accessed: March 11, 2020Google Scholar The age-standardised declines in the prevalence, morbidity, and mortality of chronic respiratory diseases over the past three decades are encouraging. These trends should inspire governments, world organisations, medical societies, health systems, health-care providers, and individuals in the community to continue to advocate for clean air, tobacco-free environments, and access to care. Similar to the concept of cardiovascular health, it is time to shift the paradigm from prevention of respiratory disease to promotion of respiratory health.12Reyfman PA Washko GR Dransfield MT Spira A Han MK Kalhan R Defining impaired respiratory health. A paradigm shift for pulmonary medicine.Am J Respir Crit Care Med. 2018; 198: 440-446Crossref PubMed Scopus (12) Google Scholar Such an initiative calls for continued research on individual-level and population-level factors associated with increased susceptibility to impaired respiratory health. WWL has received non-financial support from Pulmonx and personal fees from Konica Minolta outside of the submitted work. MKH has received personal fees from GlaxoSmithKline, Boehringer Ingelheim, AstraZeneca, Mylan, and Merck, and non-financial support from Novartis and Sunovion outside of the submitted work. Prevalence and attributable health burden of chronic respiratory diseases, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017Our study shows that chronic respiratory diseases remain a leading cause of death and disability worldwide, with growth in absolute numbers but sharp declines in several age-standardised estimators since 1990. Premature mortality from chronic respiratory diseases seems to be highest in regions with less-resourced health systems on a per-capita basis. Full-Text PDF Open Access