Prevalence and Risk Factors of Chronic Obstructive Pulmonary Disease Among Tibetans Living at High Altitudes

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a major public health problem in China. Because of regional diversity in the geography and financial resources of various regions in China, data on the prevalence and risk factors of COPD in high altitude Chinese populations, including Tibetans, are limited. Methods: This prospective cross-sectional study of six urban and rural Tibetan regions in China was performed using stratified-cluster random sampling. A revised questionnaire was used to interview every participant, who all underwent chest radiography and pre- and post-bronchodilator pulmonary function testing. The diagnostic criteria used for COPD was based on the Global Initiative for Chronic Obstructive Lung Disease. Findings: The study was composed of a representative sample of 3,741 participants aged 15-83 years who had satisfactory spirograms. The overall prevalence of COPD was 4*9% (95% confidence interval [CI]: 4*2%-5*6%). The difference between men and women (4*9% [3*9%-5*9%] vs 5*0% [4*0%-5*9%]; P=0*922) was not significant, but a higher prevalence of COPD was found in participants aged =40 years (8*0% [6*7%-9*2%]) than in those aged 15-39 years (2*3% [1*6%-2*9%], P<0*001). By multivariable adjusted analysis, age, lower altitude, biomass smoke, and a history of tuberculosis were significantly associated with a higher prevalence of COPD, while education was associated with a lower prevalence. Interpretation: COPD was prevalent in Tibetans aged older than 15 years and is a major health burden in high altitude regions. Biomass smoke may be a highly significant risk factor of COPD among Tibetans at high altitude. Preventing exposure to pollution caused by biomass smoke should be a public health priority for high-altitude residents. Funding: Ministry of Health and Ministry of Science and Technology of China Declaration of interests: All authors declare no competing interests. The study protocol was approved by the institutional review board or ethics committee of Beijing Hospital.