COPD cases more common at high altitude, new study suggests
‘Fresh’ mountain air is possibly not always as healthy for the lungs as assumed: research has found that COPD cases occur more frequently in areas of high altitude when compared with areas of low altitude in rural Kyrgyzstan, according to new findings.
Study authors suggest that the reason for this is linked to indoor air pollution generated by cooking stoves and fires for heating.
Researchers from Leiden University Medical Centre (LUMC), the University Medical Centre in Groningen (UMCG) and colleagues from Kyrgyzstan conducted lung function tests among 199 residents of high-altitude areas and 193 residents of low altitude areas in Kyrgyzstan.
The results show that COPD occurred more frequently in the group of people living in the high-altitude area – 36.7% versus 10.4%. The study also analysed particulate matter concentrations, which are an indicator of how clean the air is. The results showed that concentrations in the mountains reached values that were more than 11 times higher than the daily maximum concentrations recommended by the World Health Organization (WHO).
The study found a clear relationship between high indoor air particulate matter concentrations and the occurrence of COPD, even when other risk factors such as age and smoking were accounted for. The high levels of concentrations can be explained by the environmental conditions of living at high altitude. The extreme cold weather, with temperatures of up to -20°C in winter, means that residents keep windows and doors closed and ventilate their homes less, while burning more fuel for cooking and heating. All highland residents relied on biomass fuels for cooking and heating, mostly from the dung of the sheep they herd, which generates much smoke.
Another important risk factor for COPD was living at high altitude. This could be explained by the influence of altitude on lung development, or by unmeasured factors between high- and lowlands, such as socioeconomic status.
"Our research shows that preventive measures concerning air pollution indoors are of great importance, especially in the rural mountains. Awareness of the risks of burning biomass and offering alternatives, such as clean cooking ovens and stoves, can be important steps ", says LUMC PhD student Evelyn Brakema.
The results have been discussed with the Kyrgyz Minister of Health and have contributed to the decision of the World Bank to distribute tens of thousands of clean cookstoves to the country.
This study was funded by Healthy Lungs for Life. The results have contributed to the start of the FRESHAIR research project, funded by Horizon2020, which the European Lung Foundation was a partner in.