<p>Associated Factors and Comorbidities of Airflow Limitation in Subjects Undergoing Comprehensive Health Examination in Japan – Survey of Chronic Obstructive Pulmonary Disease Patients Epidemiology in Japan (SCOPE- J)</p>

Abstract

To identify associated factors of having at least one of the airflow limitation, chronic cough/phlegm, and currently treated respiratory diseases in health examinees, and to describe the characteristics of each subgroup classified by comorbidities. Subjects and Methods: This was an observational cross-sectional survey carried out in multiple regions of Japan. Subjects aged 40 years older, undergoing comprehensive health examination, were recruited. Airflow limitation was defined as having forced expiratory volume in 1 s/forced vital capacity lower than 70%. Associated factors of having at least one of the airflow limitation, chronic cough/phlegm, and currently treated respiratory diseases were examined by logistic regression analysis. Subgroup classification by comorbidity patterns was conducted by hierarchical cluster analysis. Results: In a total of 22,293 subjects, 1520 (6.8%) had at least one of the airflow limitation, chronic cough/phlegm, and currently treated respiratory diseases. With this objective variable, the following explanatory variables were significantly associated: older age, higher total score in the chronic obstructive pulmonary disease assessment test (CAT) and coexistence of lung cancer (common in ever-smokers and never-smokers), higher pack-years, lower body mass index, higher C-reactive protein, without coexistence of diabetes mellitus (specific in ever-smokers), male sex, coexistence of anxiety, and sleep disorder (specific in neversmokers). Among the 1520 subjects, 1512 subjects with smoking history data were classified by comorbidity patterns into subgroups of "no comorbidities," "mixed comorbidities," "inflammatory comorbidities," "overweight," "underweight," and "chronic kidney disease." "Inflammatory comorbidities" were specific in ever-smokers, and "underweight" was specific in never-smokers. Conclusion: Several factors were identified as associated factors of having at least one of airflow limitation, chronic cough/phlegm, and currently treated respiratory diseases and they were different between ever-smokers and never-smokers. Different comorbidity patterns were observed by smoking history. These findings could provide information to assist the management of subjects with COPD or at risk for COPD in the general population.

Association Between Osteoporosis Self-Assessment Tool for Asians and Airflow Limitation in Japanese Post-Menopausal Women

“… 32 Epidemiologic studies have shown that the prevalence of AL defined according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria tends to be higher in older generations, and AL was observed in participants in their 40s. 23 , 33 It is unclear whether the high prevalence of AL in older patients is caused by long-term exposure to factors that induce AL or aging effects. Although the use of FEV 1 /FVC<70% for diagnosing COPD in the elderly is controversial, a fixed FEV 1 /FVC <70% value is widely regarded as a diagnostic criterion according to the GOLD.…”

“…However, these excluded individuals could have had COPD or asthma; thus, we expressed “AL” instead of COPD. 22 , 23 Third, the sample size of the study population was limited. Moreover, the modest size of the study population and sampling bias as participants were recruited from among those who underwent optional BMD measurement (DXA).…”

“…As previously described, the screening examinations included physical assessments, questionnaires, and blood collection. 22 , 23 A trained public health nurse administered questionnaires to collect data on the medical history, including medication use, alcohol consumption, smoking status, and physical activity.…”

“…Pulmonary function tests were performed using an electronic spirometer (DISCOM-21 FX; CHEST MI, Tokyo, Japan), as previously described. 22 , 23 …”