Prevalence of comorbidities in subjects with airflow obstruction in Japan

Background: COPD is one of the leading causes of mortality in Japan. Little is known about the prevalence of comorbid conditions in subjects with COPD in Japan. Objective: The aim of this study was to examine the prevalence of comorbidities between subjects with and without airflow obstruction (AO). Methods: This study included 19,340 subjects (11,549 men, 7,791 women), aged 16-96 years, who underwent spirometric lung function tests at a medical check-up held between April 2009 and March 2010 at the Japanese Red Cross Kumamoto Health Care Center, Kumamoto, Japan. Data on medical history and life style information were collected by means of interview questionnaires. All subjects were evaluated by a physician. AO was defined according to Global Institute for Chronic Obstructive Lung Disease (GOLD) criteria (FEV1/FVC<0.7). Results: In logistic regression models adjusted for age, smoking and BMI, prevalence of subjects with diabetes (odds ratio (OR), 1.28; 95% confidence intervals (95%CI), 1.08-1.51), asthma (OR, 4.09; 95%CI, 3.15-5.31) and lung cancer (OR, 3.84; 95%CI, 1.89-7.80) were significantly higher in subjects with AO compared to subjects without AO in male. In female, prevalence of subjects with hypertension (OR, 1.43; 95%CI, 1.15-1.79), diabetes (OR, 1.40; 95%CI, 1.05-1.86), asthma (OR, 3.22; 95%CI, 2.22-4.67) and lung cancer (OR, 4.52; 95%CI, 1.62-12.62) were significantly higher in subjects with AO compared to subjects without AO. Conclusions: This study documented that numerous comorbidities are frequently associated with AO. Therefore, efforts toward earlier detection of AO and the identification of comorbidities may become an integral part of the core prevention of COPD.