Nepal was one of the countries with the highest concentration of people disabled by chronic obstructive pulmonary disease (COPD) in 2015, according to a new study published by The Lancet Respiratory Medicine on Thursday. 

About 3.2 million people worldwide succumbed that year to COPD, a group of lung conditions including emphysema and bronchitis that make it difficult to breathe, caused mainly by smoking and pollution, the Lancet tally showed. Around 400,000  people died from asthma. COPD and asthma are two most common chronic lung diseases.

Asthma is twice as prevalent, but COPD is eight times more deadly, the study found. Both diseases can be treated affordably, but many sufferers are often left undiagnosed, misdiagnosed or under-treated.

COPD was the fourth-ranked cause of death worldwide in 2015, according to the World Health Organization, behind heart disease (nine million), stroke (six million) and lower respiratory infections (just over 3.2 million).

Researchers led by Theo Vos, a professor at the Institute of Health Metrics and Evaluation at the University of Washington, analysed data from 188 countries to estimate, in each one, the number of cases and deaths annually from 1990 to 2015.

COPD prevalence and death rates declined over that period, but the overall numbers increased—with nearly 12 percent more deaths— because of population growth. For asthma, prevalence went up by almost 13 percent to 358 million people worldwide, but the number of deaths dropped by more than a quarter.

“These diseases have received less attention than other prominent non-communicable diseases like cardiovascular disease, cancer or diabetes,” Vos said in a statement. 

The other countries with the highest concentration of people disabled by COPD in 2015 were Papua New Guinea, India and Lesotho.

For asthma, the biggest disease burdens were found in Afghanistan, the Central African Republic, Fiji, Kiribati, Lesotho, Papula New Guinea and Swaziland.

High-income Asian nations were least affected by COPD, along with countries in central Europe, north Africa, the Middle East and western Europe. Central and eastern Europe, along with China, Japan and Italy, had among the lowest rates of asthma.

Smoking is known to aggravate asthma, as are allergens, whether indoors or in nature.

Indoor cooking is also a major culprit for chronic lung diseases, the authors noted.