Global trends emerge in chronic respiratory disease mortality, disability

A study recently published in The BMJ suggests that the number of total deaths worldwide due to chronic respiratory diseases has increased during the past 3 decades, although age-standardized mortality rates have generally declined.

Using data from the Global Burden of Diseases, Injuries and Risk Factors Study 2017, the researchers examined temporal and geographic trends of mortality and disability-adjusted life-years, by age and sex, due to chronic respiratory diseases, including COPD, asthma, pneumoconiosis and interstitial lung disease and pulmonary sarcoidosis, from 1990 to 2017 around the world.

During the study period, the number of deaths due to chronic respiratory diseases increased by 18%, rising from 3.32 million in 1990 to 3.91 million in 2017. Age-standardized mortality rates for chronic respiratory diseases, however, decreased annually by an average of 2.41%.

When evaluated according to specific respiratory diseases, results revealed annual declines in global age-standardized mortality rates for COPD (2.36%), pneumoconiosis (2.56%) and asthma (3.4%) from 1990 to 2017. The mortality rate for ILD and pulmonary sarcoidosis, however, increased by an average of 0.97% per year during the study period.

A study recently published in The BMJ suggests that the number of total deaths worldwide due to chronic respiratory diseases has increased during the past 3 decades, although age-standardized mortality rates have generally declined.

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In terms of disability, DALYs ranged from 97.2 million to 112.3 million from 1990 to 2017. During the study, DALYs due to asthma and pneumoconiosis declined, but those due to COPD and ILD and pulmonary sarcoidosis increased from 1990 to 2017.

There were also notable variations in mortality rates, changes in mortality rates and disability across the 195 countries included in the study, according to the researchers.

Overall, age-standardized mortality and age-standardized DALY rates of chronic respiratory diseases decreased for both sexes throughout the study period, but the decline in mortality was markedly higher in men vs. women. Additionally, the number of deaths for COPD, pneumoconiosis, asthma and ILD and pulmonary sarcoidosis rose with increasing age, with more pronounced increases among adults older than 70 years.

The researchers also assessed a number of factors that could explain the rates of death and disability due to chronic respiratory diseases. Sociodemographic index, which is a composite indicator of income per capita, average education level and total fertility rates, was a key factor affecting mortality and disability rates, according to the data, with regions with the lowest sociodemographic index having the highest mortality and DALYs.

In 2017, tobacco use, including smoking and secondhand smoke, was the major risk factor for mortality and disability due to COPD — accounting for 1.41 million death and 33.01 million DALYs — followed by pollution from particulate matter, which accounted for 1 million deaths and 25.12 million DALYs.

For the study period, particulate matter pollution and occupational risks strongly correlated with COPD mortality, with particulate matter pollution explaining most of the COPD deaths in regions with a low sociodemographic index.

For asthma, high BMI has emerged as the most critical risk factor for DALYs since 2003 and has accounted for the most asthma-related deaths since 2013, with notable differences according to sociodemographic index. Specifically, in regions with low sociodemographic index, smoking was the most important risk factor for asthma, whereas high BMI accounted for most asthma-related deaths in areas with higher sociodemographic-index areas. Occupational asthmagens also appeared to be strong risk factors for asthma, accounting for 6.7% of asthma-related deaths in 2017.

“Aging and risk exposures, including smoking, environmental pollution and a high body mass index, are the main drivers of mortality and should receive more attention with supportive policies,” the researchers wrote. – by Melissa Foster

Disclosure: This study was supported by the National Key R&D Program of China and the National Natural Science Foundation of China. The authors report no relevant financial disclosures.