Prevalence and risk factors of airflow limitation in a Mongolian population in Ulaanbaatar: Cross-sectional studies

<div><p>The burden of chronic obstructive pulmonary disease (COPD) is expected to increase in the coming decades. In Ulaanbaatar, Mongolia, air pollution, which has been suggested to correlate with COPD, is a growing concern. However, the COPD prevalence in Ulaanbaatar is currently unknown. This study aims to estimate the prevalence of airflow limitation and investigate the association between airflow limitation and putative risk factors in the Mongolian population. Five cross-sectional studies were carried out in Ulaanbaatar. Administration of a self-completed questionnaire, body measurements, and medical examination including spirometry were performed in 746 subjects aged 40 to 79 years living in Ulaanbaatar. The age- and sex-standardized prevalence of airflow limitation in Ulaanbaatar varied widely from 4.0 to 10.9% depending on the criteria for asthma. Age, body mass index (BMI), and smoking habit were independent predictors for airflow limitation while residential area and household fuel type were not significant. In conclusion, prevalence of putative COPD was 10.0% when subjects with physician-diagnosed asthma were excluded from COPD. Older age, lower BMI, and current smoking status were putative risk factors for airflow limitation. This prevalence was consistent with reports from Asian countries.</p></div

Additional file 1: Table S1. of Effects of air pollution and seasons on health-related quality of life of Mongolian adults living in Ulaanbaatar: cross-sectional studies

Factors associated with HR-QoL of Mongolian subjects. (DOCX 44 KB

Characteristics of the study subjects with valid spirometry.

<p>Characteristics of the study subjects with valid spirometry.</p

Factors affecting the prevalence of airflow limitation.

<p>Factors affecting the prevalence of airflow limitation.</p

Prevalence of airflow limitation in study population standardized by Mongolian population.

<p>Prevalence of airflow limitation in study population standardized by Mongolian population.</p

Age-specific impacts of body fat mass (BFM) on deciding FEF₅₀ and FEF₇₅ estimated for three different age groups of male and female participants.

<p>(A): Partial regression coefficients of Ln(BFM) for reference means of Ln(FEF₅₀) in young-, middle-, and advanced-age groups of either gender. They are expressed as ΔLn(FEF₅₀)/ΔLn(BFM). (B): Partial regression coefficients of Ln(BFM) for Ln(FEF₇₅) are defined as ΔLn(FEF₇₅)/ΔLn(BFM).</p

Demographic, anthropometric, and spirometric characteristics of male participants.

<p>Values are the means ± SD. BMI: body mass index. %FAT: fat percentage of body mass. BFM: body fat mass calculated from body mass (kg) multiplied by %FAT/100. ^*: significantly different from the young-age group (at least p<0.01). ^†: different from the middle-age group (at least p<0.01).</p

Demographic, anthropometric, and spirometric characteristics of female participants.

<p>Values are the means ± SD. Symbols are the same as denoted in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100733#pone-0100733-t001" target="_blank">Table 1</a>. ^*: different from the young-age group (at least p<0.03). ^†: different from the middle-age group (at least p<0.03).</p

Age-specific impacts of height (H) on PEF and FEF₅₀ estimated for three different age groups of both men and women.

<p>(A): Partial regression coefficients of Ln(H) for reference means of Ln(PEF) in young-, middle-, and advanced-age groups of either gender. Partial regression coefficients of Ln(H) for ΔLn(PEF) are defined as ΔLn(PEF)/ΔLn(H). (B): Partial regression coefficients of Ln(H) for Ln(FEF₅₀) are defined as ΔLn(FEF₅₀)/ΔLn(H).</p

Age-specific effects of height (H) on decision of FEV₁/FVC and FEF₇₅ estimated for three different age groups of male and female participants.

<p>(A): Partial regression coefficients of Ln(H) for reference means of Ln(FEV₁/FVC) in young-, middle-, and advanced-age groups of either gender. Partial regression coefficients of Ln(H) for Ln(FEV₁/FVC) are denoted as ΔLn(FEV₁/FVC)/ΔLn(H). (B): Partial regression coefficients of Ln(H) for Ln(FEF₇₅) are designated as ΔLn(FEV₇₅)/ΔLn(H).</p