Incidence and risk of chronic obstructive pulmonary disease in a Korean community-based cohort

Ah Young Leem,1 Boram Park,2 Young Sam Kim,1 Ji Ye Jung,1 Sungho Won2 1Division of Pulmonology, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, 2Department of Epidemiology and Biostatistics, School of Public Health, Seoul National University, Seoul, Korea Purpose: COPD is a leading cause of morbidity and mortality. However, few studies have used spirometry to investigate its incidence, especially in Asia. In the present study, we analyzed the incidence and risk factors of COPD using a community cohort database in Korea. Patients and methods: The study included 6,517 subjects aged 40–69 years from the Ansung–Ansan cohort database I–III (2001–2006). We calculated the crude incidence rate and the standardized incidence rate corrected for the Korean general population and the world population with COPD. We also determined the relative risks (RRs) for incident COPD and the attributable risks. Results: In total, 329 new COPD cases were diagnosed during follow-up. The overall crude incidence rate per 100,000 person-years was 1,447. The standardized incidence rate corrected for the Korean general population was 1,550; this value was higher in men and increased with increasing age. Risk factors for incident COPD were age ≥60 years (adjusted RR [aRR] =2.52 vs age <60 years), male sex (aRR =2.02 vs female), heavy smoking (≥20 pack-years; aRR =2.54 vs never smoker), and lowest income group (first quartile; aRR =2.03 vs fourth quartile). The adjusted attributable risk was highest for education level of high school or lower (44.9%), followed by smoking history (25.8%), income (22.9%), and sex (12.0%). Conclusion: In Korea, 15.5/1,000 people are diagnosed with COPD annually. The incidence rate increases with increasing age, heavier smoking, and decreasing income, with a higher rate in men than in women. Keywords: chronic obstructive pulmonary disease, incidence rate, relative risk, attributable ris

Comorbidities in obstructive lung disease in Korea: data from the fourth and fifth Korean National Health and Nutrition Examination Survey

Hee Jin Park, Ah Young Leem, Sang Hoon Lee, Ju Han Song, Moo Suk Park, Young Sam Kim, Se Kyu Kim, Joon Chang, Kyung Soo Chung Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Severance Hospital, Institute of Chest Disease, Yonsei University College of Medicine, Seoul, South Korea Background: Comorbidities can occur frequently in patients with chronic obstructive pulmonary disease (COPD) and can influence mortality and morbidity independently. It is increasingly recognized that many patients with COPD have comorbidities that have a major impact on their quality of life and survival. Therefore, we investigated the prevalence of comorbidities in Korean COPD populations. Methods: We used data obtained in the 6 years of the fourth and fifth Korean National Health and Nutrition Examination Survey (KNHANES) IV and V. Among 50,405 subjects, 16,151 subjects aged ≥40 years who performed spirometry adequately were included in this study. Airway obstruction was defined as forced expiratory volume in 1 second/forced vital capacity <0.7, and the Global Initiative For Chronic Obstructive Lung Disease stage was used to evaluate the severity of airway obstruction. Statistical analyses were performed using SAS 9.2. Results: Among the 16,151 subjects (43.2% male, 56.8% female; mean age: 57.1 years for men and 57.2 years for women), 13.1% had obstructive lung function; 11.3%, restrictive lung function; and 75.6%, normal lung function. Among individuals with obstructive lung function, 45.3%, 49.4%, and 5.3% had mild, moderate, and severe and very severe airflow limitation. The prevalence of hypertension, diabetes mellitus (DM), underweight, and hypertriglyceridemia was higher in the obstructive lung function group than in the normal lung function group (49.6% vs 35.2%; 16.8% vs 10.5%; 3.3% vs 1.3%; 19.7% vs 17.0%). According to the severity of airway obstruction, hypertension and underweight were more common as severity increased, although the prevalence of DM and hypertriglyceridemia was lower in subjects with severe airway obstruction. The prevalence of hypercholesterolemia, overweight, and osteoarthritis was lower in the obstructive lung function group, especially in the severe airway obstruction groups. Conclusions: Overall, our analysis is similar to research that was conducted earlier. Our study showed that hypertension and underweight are common comorbidities in COPD patients, and are higher as the severity of airflow obstruction increased in both men and women. DM, hypertriglyceridemia, and low high-density lipoprotein cholesterol are more common in subjects with airway obstruction, although their incidence is lower in the severe group. Keywords: chronic obstructive pulmonary disease, comorbidity, hypertension, underweigh

Relationship between blood levels of heavy metals and lung function based on the Korean National Health and Nutrition Examination Survey IV–V

Ah Young Leem, Se Kyu Kim, Joon Chang, Young Ae Kang, Young Sam Kim, Moo Suk Park, Song Yee Kim, Eun Young Kim, Kyung Soo Chung, Ji Ye Jung Division of Pulmonology, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea Background: Heavy metal exposure may contribute to inflammation in the lungs via increased oxidative stress, resulting in tissue destruction and obstructive lung function (OLF). In this study, we evaluated the relationship between lead and cadmium levels in blood, and lung function in the Korean population.Methods: Pooled cross-sectional data from 5,972 subjects who participated in the Korean National Health and Nutrition Examination Survey 2008–2012 were used for this study. OLF was defined as forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) <0.7. Graphite-furnace atomic absorption spectrometry was used to measure levels of lead and cadmium in blood.Results: Adjusted means for age, sex, body mass index, and smoking status in blood lead and cadmium levels were increased with age and were higher in men and current smokers. The FEV1/FVC ratio was lower in the highest quartile group of lead (78.4% vs 79.0%; P=0.025) and cadmium (78.3% vs 79.2%; P<0.001) concentrations, compared with those in the lowest quartile groups. Multiple linear regression demonstrated an inverse relationship between the FEV1/FVC ratio and concentrations of lead (estimated -0.002; P=0.007) and cadmium (estimated -0.005; P=0.001). Of the 5,972 subjects, 674 (11.3%) were classified into the OLF group. Among current smokers, the risk of OLF was higher in subjects in the highest quartile group of cadmium concentration than in those in the lowest quartile group (odds ratio 1.94; 95% confidence interval 1.06–3.57).Conclusion: We demonstrated a significant association between the FEV1/FVC ratio and blood concentrations of lead and cadmium in the Korean population. The risk for OLF was elevated with increasing concentrations of cadmium among current smokers. Keywords: lead, cadmium, pulmonary function, obstructive lung diseas

Relationship between depression and lung function in the general population in Korea: a retrospective cross-sectional study

Youngmok Park, Ji Ye Jung, Young Sam Kim, Kyung Soo Chung, Joo Han Song, Song Yee Kim, Eun Young Kim, Young Ae Kang, Moo Suk Park, Joon Chang, Ah Young Leem Division of Pulmonology, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seodaemun-gu, Seoul, South Korea Background: Lung function and depression are closely related to many chronic lung diseases. However, few studies have evaluated this association in the general population. In this study, we evaluated the relationship between lung function and depression in the general population in Korea. Participants and methods: Data from the Ansung–Ansan cohort, a community-based cohort in Korea, were used to analyze the relationships between depression and lung function parameters. A total of 3,321 men and women aged 40–69 years were enrolled. Spirometry data included the forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and the FEV1/FVC ratio. Depression was defined as a score of ≥16 by the Beck Depression Inventory (BDI). A propensity score analysis was conducted with the aim of reducing the bias of the retrospective study. Results: The overall prevalence of depression in the study population was 13.1% (434/3,321 participants). Depression was significantly more prevalent in women than in men (P<0.001) and in never smokers than in ever smokers (P<0.001). The group with depression was older (P<0.001) and had a lower average body mass index (BMI) (P=0.015) than the group without depression. The FEV1 (P<0.001), FVC (P<0.001), and FEV1/FVC ratio (P=0.022) were significantly lower in the group with depression than in the group without depression. After adjusting for age, sex, BMI, and smoking status, the mean FEV1 was lower in the group with a high BDI score than in the group with a low BDI score (P=0.044). Using multiple linear regression analysis and adjusting for covariates, no statistically significant relationship between lung function and the BDI score was found. However, the BDI score and FEV1 were inversely related in subjects older than 50 years (P=0.023). Conclusion: Depression is associated with decreased lung function in the general population, especially in adults older than 50 years. Keywords: Beck Depression Inventory, COPD, depression, lung functio