Major Chronic Respiratory Diseases in Chiang Mai: Prevalence, Clinical Characteristics, and Their Correlations

To identify the prevalence, clinical characteristics, disease severity, and correlations of major chronic respiratory diseases (CRDs) among the adult population living in Chiang Mai.

A cross-sectional study was conducted with adults living in municipal areas of Chiang Mai. All clinical relevant data collected by face-to-face interview was confirmed by pulmonologists. The chest radiographic findings and post-bronchodilator spirometry were done in all subjects. The aeroallergen skin test and rhinoscopy were performed in all chronic rhinitis and asthma subjects.

Five hundred seventy four subjects with mean age 52.9±10.0 years, 59.6% female, and 37.5% smokers were recruited. The prevalence of overall CRDs was 59.2%. Chronic rhinitis was the most prevalent chronic respiratory disease (n = 239, 41.6%), followed by asthma (n = 58, 10.1%), and chronic obstructive pulmonary disease (COPD) (n = 21, 3.7%). The most common abnormal pulmonary function test was restrictive lung disorders (n = 53, 9.6%). Asthma subjects were determined to be more allergic than chronic rhinitis subjects (58.1% vs. 39.9%, p-value = 0.033). Regarding the disease severity, 14.9% of chronic rhinitis and 10.3% of asthma subjects were classified as moderate to severe degree, whereas 81% of chronic obstructive pulmonary disease subjects were classified as moderate to very severe degrees. In asthma patients, there were positive association with chronic rhinitis (OR 3.9, 95% CI 2.1-7.0, p-value <0.001).

The prevalence of major CRDs in adults among Chiang Mai population was significantly high with overlapped respiratory symptoms and varying disease severity. Additionally, chronic rhinitis had correlation with asthma but not with COPD.