Sex differences in chronic obstructive pulmonary disease characteristics: the Korea National Health and Nutrition Examination Survey 2007-2018.

BACKGROUND/AIMS: Chronic obstructive pulmonary disease (COPD) is less prevalent in females than males, but it affects mortality in females. There may be sex differences in the clinical characteristics of COPD. METHODS: We analyzed the Korea National Health and Nutrition Examination Survey dataset from 2007 to 2018. We compared the clinical characteristics and comorbidities in subjects with COPD according to sex. We adjusted the multivariate logistic regression of lung cancer prevalence according to COPD and sex by age and smoking amount. RESULTS: Females with COPD tended to be older than males with COPD (64.1 ± 0.4 yr vs. 62.3 ± 0.2 yr, respectively, p < 0.001). Approximately 89% of males with COPD had a smoking history, while 86% of females with COPD were non-smokers (p < 0.001). Household income was lower (p < 0.001) and asthma and overall malignancy were more prevalent in females with COPD than males with COPD (25.5 vs. 11.6%, respectively, p < 0.001; (6.3 vs. 5.4%, respectively, p < 0.001). However, lung cancer was more common in males with COPD than females with COPD (0.9 vs. 0.1%, respectively, p < 0.001). Lung cancer prevalence increased in males with moderate COPD compared to subjects without COPD (OR, 4.409; 95% CI, 1.741-9.419). CONCLUSION: Females with COPD had a lower smoking rate, household income, and lung cancer prevalence than males with COPD. More active COPD screening is needed for women of low socioeconomic status, even if they do not smoke.

Acute exacerbation of COPD increases the risk of hip fractures: a nested case-control study from the Korea National Health Insurance Service.

BACKGROUND/AIMS: Hip fracture and acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) could increase mortality in patients with COPD. There are no data on the relationship between AE-COPD and hip fracture, which may significantly affect the prognosis of patients with COPD. Therefore, we conducted this study to determine the effects of AE-COPD on hip fractures in patients with COPD. METHODS: This retrospective, nested, case-control study included 253,471 patients with COPD (≥ 40 years of age) identified from the Korea National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS) from 2002 to 2015. Among 176,598 patients with COPD, 1,415 patients with hip fractures were identified. Each case was matched to one control for age (within 10 years), sex, and year of COPD diagnosis. We estimated the adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for hip fractures associated with AE-COPD using conditional logistic regression analysis, adjusting for underlying diseases and smoking history. RESULTS: In patients with AE-COPD, the risk of hip fracture was 2.50 times higher, regardless of systemic corticosteroid use and underlying disease (aOR, 2.50; 95% CI, 1.67 to 3.75). The risk of hip fracture increased if there was one episode of AE in the year before hip fractures (aOR, 2.25; 95% CI, 1.66 to 3.05). Moreover, the risk of hip fracture also increased in patients with more than two episodes of AE the year before hip fractures (aOR, 2.57; 95% CI, 1.61 to 4.10). CONCLUSION: AE-COPD increases the risk of hip fracture regardless of underlying diseases, including osteoporosis, and treatment with systemic corticosteroids.

A pilot investigation of e-cigarette use and smoking behaviour among patients with chronic airway disease or respiratory symptoms.

BACKGROUND: This pilot study aimed to investigate the current status of e-cigarettes (ECs) use patterns among patients with chronic airway disease or chronic respiratory symptoms and the effects of ECs use on respiratory and mental health. METHODS: A cross-sectional survey was conducted at the outpatient clinic of eight teaching hospitals in South Korea between November 2019 and December 2019. All adult ECs users (19 years and above) who visited the outpatient clinic as a patient with chronic airway disease or chronic respiratory symptoms were eligible to participate in this study. RESULTS: A total of 51 subjects responded to the survey. Most of the participants were male (92.2%) and the mean age was 41.8 years. Dominant airway diseases were asthma and chronic obstructive pulmonary disease. Most of the subjects had a history of cigarette smoking, and 19 subjects were dual users of current cigarettes and ECs. Most of the subjects started ECs use due to health-related reasons. When comparing exclusive ECs users and dual users, St. George's respiratory questionnaire (SGRQ) scores, the proportion of cases with moderate to severe depressive symptoms, and average Fagerstrom test for nicotine dependence scores for ECs were higher in dual users than exclusive ECs users (mean 4.64 vs. 2.38, p = 0.006), respectively. CONCLUSION: Most of the subjects started ECs use due to health concerns, but dual users have more respiratory symptoms and higher nicotine dependence in this pilot study. One hypothesis that comes from these results is that greater nicotine dependence may influence behaviours, habits, and views about ECs. These preliminary observations need confirmation in a large cohort.

E-cigarette-associated Severe Pneumonia in Korea Using Data Linkage between the Korea National Health and Nutrition Examination Survey (KNHANES, 2013-2019) and the National Health Insurance Service (NHIS) Claims Database.

BACKGROUND: This study aimed to investigate the association between e-cigarette (EC) use and development of acute severe pneumonia in the Korean population using a national database. METHODS: We conducted a retrospective analysis using linkage of data between the Korean National Health and Nutrition Examination Survey (KNHANES) and the National Health Insurance Service (NHIS) administrative claims database. The primary endpoint of this study was development of severe pneumonia requiring hospital admission according to EC use during the study period. The secondary endpoints were in-hospital mortality, intensive care unit (ICU) admission, ventilator care, and days of hospital stay. RESULTS: The final analysis included 28,950 individuals, of which 578 (2.0%) were EC users. EC users were younger and more often male than non-EC users. The EC users showed higher level of education and household income and had fewer comorbidities. Severe pneumonia was noted in 37 of 28,372 non-EC users (0.13%), but there were no occurrences of severe pneumonia in EC users. The incidence of pneumonia occurrence was not different between the two groups (P = 1.000). CONCLUSIONS: Since e-cigarette or vaping use-associated lung injury (EVALI) is most likely included in acute severe pneumonia occurring within 3 months of EC use, it is considered that there might be no EVALI patients in Korea during the investigation period. A large-scale, prospective study is necessary to evaluate the association between EC use and acute lung injury.

Nicotine Dependence and Stress Susceptibility in E-Cigarette Smokers: The Korea National Health and Nutrition Examination Survey 2013-2017.

BACKGROUND: E-cigarettes are steadily gaining popularity in Korea. However, the characteristics of e-cigarette smokers, especially nicotine dependence and stress susceptibility, have not been evaluated in comparison to those of non-smokers or combustible cigarette smokers in Korea. METHODS: In this study, 28,059 participants from the Korea National Health and Nutrition Examination Survey (2013-2017) were classified into the following three groups: non-smokers, smokers (current smokers and ex-smokers of combustible cigarettes only), and e-smokers (current smokers and ex-smokers of e-cigarettes regardless of combustible cigarette use). RESULTS: Among the participants, 16,980 (60.5%), 9,247 (33.0%), and 1,832 (6.4%) subjects were non-smokers, smokers, and e-smokers, respectively. E-smokers were younger, more educated, and had a higher household income than non-smokers or smokers. The number of e-smokers who smoked within 5 minutes of waking up (31.5% vs. 19.8%, p<0.001) and who planned to quit smoking within 6 months (39.1% vs. 35.7%, p<0.05) was greater than that of smokers. E-smokers perceived stress as "very much" (7.0% vs. 4.4%, p<0.001) and "a lot" (29.1% vs. 20.5%, p<0.001) compared to non-smokers. Suicidal ideation (6.5% vs. 4.7%, p<0.001), plans (2.4% vs. 1.3%, p<0.001), and attempts (1.1% vs. 0.5%, p<0.001) were higher in e-smokers than in non-smokers. Depressive episodes in 1 year (14.2% vs. 11.4%, p<0.05) and suicidal plans (2.4% vs. 1.8%, p<0.05) were more frequent among e-smokers than among smokers. CONCLUSION: E-smokers were younger, more educated, and had a higher income, but they were more dependent on nicotine and susceptible to stress than non-smokers and smokers. Smoking cessation counseling should be tailored according to the characteristics of e-smokers.

Directions and Challenges in Smoking Cessation Treatment.

Raising the tax on tobacco-related products is the most effective and sustainable intervention for smoking cessation. The 2015 tobacco-tax increase resulted in a decreased smoking rate among Korean adult men. However, participation in the government-sponsored smoking-cessation programs developed after the 2015 tobacco tax increase has declined sharply since 2018. The popularity of electronic cigarettes (e-cigarettes) seems to be an important factor in this decline. Indeed, the market share of e-cigarettes has increased steadily since 2007, when the e-cigarette was introduced in Korea as a vaporizer. The introduction of the tobacco-heating device IQOS in 2017 resulted in the skyrocketing popularity of e-cigarettes, especially among the young generation of Koreans. The U.S. Food and Drug Administration (FDA) authorized marketing of IQOS as a "reduced exposure" tobacco product on July 7, 2020, further complicating smoking-cessation efforts. The agency announced that IQOS produces fewer or lower levels of some toxins than combustible cigarettes. However, FDA authorization does not mean that these products are safe. There is no evidence that reducing the harmful chemical components leads to health benefits. Clinicians need to maintain the position that those who smoke, regardless of tobacco-product type, should be counseled for smoking cessation and prescribed appropriate proven pharmacologic agents.

Blood lead levels in relation to smoking and chronic obstructive pulmonary disease (COPD): a study from Korean National Health and Nutrition Examination Survey (KNHANES).

BACKGROUND: Lead exposure is a resurgent environmental issue globally. Smoking can be a source of lead exposure, although the majority of lead poisonings originate from workplace exposures. However, no study has been undertaken concerning the blood lead levels based on the chronic obstructive pulmonary disease (COPD), smoking status, and other risk factors of COPD. This cross-sectional study was conducted to investigate the blood lead levels according to COPD and clinical variables associated with COPD. METHODS: Data (total number =53,829) were collected from the Korean National Health and Nutrition Examination Survey (IV in 2008 and 2009, V in 2010-2012, and VI in 2013). Multivariable linear regression analyses were performed to determine variables associated with elevated blood lead levels. RESULTS: Univariate regression analysis showed that male sex, older age, smoking, occupation level, income level, education level, and presence of COPD were related to higher blood lead levels, whereas the other co-morbidities including diabetes, hypertension, cerebral stroke, osteoporosis, asthma, and depression were not related (P<0.05). Multivariable regression analysis demonstrated that older age, male sex, smoking, occupation, and education level were independently associated with higher blood lead levels (P<0.05). CONCLUSIONS: Smoking status, occupation, and education level along with old age and male sex were independently associated with higher blood lead levels; however, COPD was not after adjustment of all confounding factors.

Single-molecule observation of ATP-independent SSB displacement by RecO in Deinococcus radiodurans.

Deinococcus radiodurans (DR) survives in the presence of hundreds of double-stranded DNA (dsDNA) breaks by efficiently repairing such breaks. RecO, a protein that is essential for the extreme radioresistance of DR, is one of the major recombination mediator proteins in the RecA-loading process in the RecFOR pathway. However, how RecO participates in the RecA-loading process is still unclear. In this work, we investigated the function of drRecO using single-molecule techniques. We found that drRecO competes with the ssDNA-binding protein (drSSB) for binding to the freely exposed ssDNA, and efficiently displaces drSSB from ssDNA without consuming ATP. drRecO replaces drSSB and dissociates it completely from ssDNA even though drSSB binds to ssDNA approximately 300 times more strongly than drRecO does. We suggest that drRecO facilitates the loading of RecA onto drSSB-coated ssDNA by utilizing a small drSSB-free space on ssDNA that is generated by the fast diffusion of drSSB on ssDNA.

Relationship of chronic obstructive pulmonary disease severity with early and late mortality in elderly patients with hip fracture.

INTRODUCTION: We conducted a comparative study to compare patients with and without chronic obstructive pulmonary disease (COPD) and to analyze the effect of COPD severity on mortality in elderly patients with hip fractures who were diagnosed by pulmonologists. The purposes of this study were to compare early and late mortality after hip fracture between COPD and non-COPD patients and to assess risk factors of mortality after hip fractures in elderly patients with COPD. METHODS: This study included 1294 patients (1294 hips) who were diagnosed as having unilateral femoral neck or intertrochanteric fractures and who underwent surgery at two hospitals between 2004 and 2017. The patients were categorized into a non-COPD group (853 patients) and a COPD group (441 patients; mild-to-moderate [354 patients] and severe-to-very severe COPD subgroups [87 patients]). The cumulative crude mortality rate was calculated, and 30-day, 60-day, 3-month, 6-month, and 1-year mortality rates were compared between the non-COPD and COPD groups. Logistic regression analysis was conducted to identify independent factors associated with mortality. RESULTS: The 30-day, 60-day, 3-month, 6-month, and 1-year postoperative cumulative mortality rates were 1.3%, 2.5%, 3.5%, 6.6%, and 10.7%, respectively, in the non-COPD group, and 2.9%, 5.7%, 7.7%, 11.8%, and 16.6%, respectively, in the COPD group (p = 0.049, p = 0.004, p = 0.002, p = 0.002, and p = 0.004, respectively). The 30-day, 60-day, 3-month, 6-month, and 1-year postoperative cumulative mortality rates in the severe-to-very severe COPD group were 4.6%, 6.9%, 11.5%, 20.7%, and 26.4%, respectively. In elderly patients with hip fracture, COPD increased the risk of mortality for 1.6 times and 1.7 times at 3 months and 1 year postoperative, respectively. In subgroup analysis, severe-to-very severe COPD was associated with 1.55-fold and 1.65-fold increased postoperative mortality risk at 6 months and 1 year respectively, as compared with mild-moderate COPD. CONCLUSIONS: In elderly patients with hip fracture, the comparison between the COPD and non-COPD patients revealed that COPD was an independent factor of mortality at a minimum of 1-year follow-up, and COPD severity in patients with hip fracture was also a risk factor of 6-month and 1-year mortality.

Procalcitonin-Guided Treatment on Duration of Antibiotic Therapy and Cost in Septic Patients (PRODA): a Multi-Center Randomized Controlled Trial.

BACKGROUND: The objective of this study was to establish the efficacy and safety of procalcitonin (PCT)-guided antibiotic discontinuation in critically ill patients with sepsis in a country with a high prevalence of antimicrobial resistance and a national health insurance system. METHODS: In a multi-center randomized controlled trial, patients were randomly assigned to a PCT group (stopping antibiotics based on a predefined cut-off range of PCT) or a control group. The primary end-point was antibiotic duration. We also performed a cost-minimization analysis of PCT-guided antibiotic discontinuation. RESULTS: The two groups (23 in the PCT group and 29 in the control group) had similar demographic and clinical characteristics except for need for renal replacement therapy on ICU admission (46% vs. 14%; P = 0.010). In the per-protocol analysis, the median duration of antibiotic treatment for sepsis was 4 days shorter in the PCT group than the control group (8 days; interquartile range [IQR], 6-10 days vs. 14 days; IQR, 12-21 days; P = 0.001). However, main secondary outcomes, such as clinical cure, 28-day mortality, hospital mortality, and ICU and hospital stays were not different between the two groups. In cost evaluation, PCT-guided therapy decreased antibiotic costs by USD 30 (USD 241 in the PCT group vs. USD 270 in the control group). The results of the intention-to-treat analysis were similar to those obtained for the per-protocol analysis. CONCLUSION: PCT-guided antibiotic discontinuation in critically ill patients with sepsis could reduce the duration of antibiotic use and its costs with no apparent adverse outcomes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02202941.

Association between secondhand smoke exposure and hypertension in never smokers: a cross-sectional survey using data from Korean National Health and Nutritional Examination Survey V, 2010-2012.

OBJECTIVES: Secondhand smoke (SHS) exposure is associated with cardiovascular disease. This study aims to determine the association between SHS exposure estimated by questionnaire and hypertension in Korean never smokers. SETTING: Korean National Health and Nutrition Examination Survey (KNHANES) V was conducted from 2010 to 2012. PARTICIPANTS: We selected the never smokers aged over 20 years who answered the question about the SHS exposure. PRIMARY AND SECONDARY MEASURES: SHS exposure in both the home and work place was estimated using a self-reporting questionnaire. We investigated the association between SHS exposure and hypertension by using multivariate analysis. And we evaluated the mean systolic and diastolic blood pressure values according to SHS exposure after adjusting for possible confounding factors. All analyses were stratified by women and men. RESULTS: There were 10 532 (women 8987 and men 1545) never smokers. We divided the subjects into three groups according to the amount of SHS exposure: none-group I, <2 hour/day-group II and ≥2 hour/day-group III. Using multivariate analysis, hypertension was more commonly associated with group III than group I in women (adjusted OR 1.50, 95% CI 1.00 to 2.04, p=0.011). Adjusted mean systolic and diastolic blood pressure values in women who were not taking antihypertensive medication were significantly elevated in group III by 2.3 and 1.7 mm Hg, respectively. CONCLUSION: SHS exposure is significantly associated with hypertension in women never smokers.

Characteristics and Clinical Outcomes of Critically Ill Cancer Patients Admitted to Korean Intensive Care Units.

BACKGROUND: The objective of this study was to investigate the characteristics and clinical outcomes of critically ill cancer patients admitted to intensive care units (ICUs) in Korea. METHODS: This was a retrospective cohort study that analyzed prospective collected data from the Validation of Simplified Acute Physiology Score 3 (SAPS3) in Korean ICU (VSKI) study, which is a nationwide, multicenter, and prospective study that considered 5,063 patients from 22 ICUs in Korea over a period of 7 months. Among them, patients older than 18 years of age who were diagnosed with solid or hematologic malignancies prior to admission to the ICU were included in the present study. RESULTS: During the study period, a total of 1,762 cancer patients were admitted to the ICUs and 833 of them were deemed eligible for analysis. Six hundred fifty-eight (79%) had solid tumors and 175 (21%) had hematologic malignancies, respectively. Respiratory problems (30.1%) was the most common reason leading to ICU admission. Patients with hematologic malignancies had higher Sequential Organ Failure Assessment (12 vs. 8, P<0.001) and SAPS3 (71 vs. 69, P<0.001) values and were more likely to be associated with chemotherapy, steroid therapy, and immunocompromised status versus patients with solid tumors. The use of inotropes/vasopressors, mechanical ventilation, and/or continuous renal replacement therapy was more frequently required in hematologic malignancy patients. Mortality rates in the ICU (41.7% vs. 24.6%, P<0.001) and hospital (53.1% vs. 38.6%, P=0.002) were higher in hematologic malignancy patients than in solid tumor patients. CONCLUSIONS: Cancer patients accounted for one-third of all patients admitted to the studied ICUs in Korea. Clinical characteristics were different according to the type of malignancy. Patients with hematologic malignancies had a worse prognosis than did patients with solid tumor.

Oligomerization of the tetramerization domain of p53 probed by two- and three-color single-molecule FRET.

We describe a method that combines two- and three-color single-molecule FRET spectroscopy with 2D FRET efficiency-lifetime analysis to probe the oligomerization process of intrinsically disordered proteins. This method is applied to the oligomerization of the tetramerization domain (TD) of the tumor suppressor protein p53. TD exists as a monomer at subnanomolar concentrations and forms a dimer and a tetramer at higher concentrations. Because the dissociation constants of the dimer and tetramer are very close, as we determine in this paper, it is not possible to characterize different oligomeric species by ensemble methods, especially the dimer that cannot be readily separated. However, by using single-molecule FRET spectroscopy that includes measurements of fluorescence lifetime and two- and three-color FRET efficiencies with corrections for submillisecond acceptor blinking, we show that it is possible to obtain structural information for individual oligomers at equilibrium and to determine the dimerization kinetics. From these analyses, we show that the monomer is intrinsically disordered and that the dimer conformation is very similar to that of the tetramer but the C terminus of the dimer is more flexible.

Factors associated with stage of change in smoker in relation to smoking cessation based on the Korean National Health and Nutrition Examination Survey II-V.

Despite a decrease in incidence, smoking remains the most serious public health problem worldwide. Identification of the factors contributing to changes in willingness to quit smoking may aid the development of strategies that encourage smoking cessation. Pooled cross-sectional data from 11,924 smokers from the Korean National Health and Nutrition Examination Survey II-V were analyzed. The stages of change in smoking cessation were categorized as pre-contemplation, contemplation, and preparation. Baseline characteristics, socioeconomic factors, quality of life, psychological status, and smoking-related factors were compared between groups. The smokers were grouped as follows: 32.4% pre-contemplation, 54.4% contemplation, and 13.1% preparation. The proportion of smokers in the pre-contemplation group decreased (from 37.4% to 28.4%) from 2001 to 2012, while the proportion in the preparation group increased (from 6.4% to 18.1%). Compared with the preparation group, after adjusting for confounding factors, the pre-contemplation group was older [≥65 years-old; odds ratio (OR) = 1.40], more often single (OR = 1.38), less educated (elementary school or lower; OR = 1.93), less physically active in terms of walking (OR = 1.38) or performing strengthening exercises (OR = 1.61), smoked more heavily (≥20 cigarettes per day; OR = 4.75), and had a lower prevalence of chronic disease (OR = 0.76). Moreover, smokers who had never received education on smoking cessation were less willing to quit than those who had (OR = 0.44). In Korean smokers, the stages of change for smoking cessation were associated with age, education, marital status, chronic diseases, physical activity, and participation in smoking cessation programs.

Epidemiological trend of pulmonary thromboembolism at a tertiary hospital in Korea.

BACKGROUND/AIMS: Despite increasing interest in pulmonary thromboembolism (PTE), data on recent trends in PTE incidence are limited. This study evaluated the recent incidence rate of PTE. METHODS: We performed a retrospective chart review of patients with PTE admitted to Chung-Ang University Hospital during the 10-year period from 2006 to 2015. Age-standardized incidence and mortality rates were calculated by the direct method per 100,000 populations. To analyze the trend of risk factor, we also calculated the proportions of cancer, major operation, and recent major fracture over that time. RESULTS: Total crude incidence rate of PTE per 100,000 was 229.36 and the age-sex adjusted standardized incidence rate was 151.28 (95% confidence interval [CI], 127.88 to 177.10). The incidence rate have been significantly increased 1.083 times annually from 2006 (105.96 per 100,000) to 2015 (320.02 per 100,000) (95% CI, 1.049 to 1.118; p < 0.001). These incidences also increased annually in age group of 35 to 54, 55 to 74, and ≥ 75 years, and in both males (odds ratio [OR], 1.071; 95% CI, 1.019 to 1.127; p = 0.007) and females (OR, 1.091; 95% CI, 1.047 to 1.136; p < 0.001). Cancer accounted for most of the increase from 20.0% at 2006 to 2007 to 42.8% at 2014 to 2015 (OR, 1.154; 95% CI, 1.074 to 1.240; p < 0.001), while the proportions of recent fracture and major operation remained constant. CONCLUSIONS: The incidence of pulmonary embolism has gradually increased over the 10 years. The increase of PTE incidence was mainly due to increased proportion of cancer patients.

Dietary vitamin C intake protects against COPD: the Korea National Health and Nutrition Examination Survey in 2012.

BACKGROUND: Vitamin C, as an antioxidant, has recently been suggested to provide protection against COPD; however, only few national cohort studies have investigated these effects. We aimed to confirm the protective effects of vitamin C against COPD in Korean patients. PATIENTS AND METHODS: We analyzed the data of 3,283 adults aged ≥40 years (representing 23,541,704 subjects) who underwent pulmonary function tests and responded to questionnaires on smoking history and vitamin C intake, with stratification variables and sampling weight designated by the Korea 2012 National Health and Nutrition Examination Survey. RESULTS: Among all the subjects, 512 (representing 3,459,679 subjects; 15.6%) were diagnosed as having COPD based on pulmonary function test results. Male gender, old age, residence in suburban/rural regions, low household income, low educational level, an occupation in agriculture or fisheries, and heavy smoking were significantly associated with COPD. Low intake of nutrients, including potassium, vitamin A, carotene, retinol, and vitamin C, was significantly associated with COPD. The prevalence of COPD in heavy smokers with the lowest quartile (Q1, <48.50 mg; 63.0%) and low-middle quartile (Q2, 48.50-84.38 mg; 56.4%) of vitamin C intake was significantly higher than that in subjects with the high-middle quartile (Q3, 84.38-141.63 mg; 29.5%) and highest quartile (Q4, >141.63 mg; 32.6%) of vitamin C intake (P=0.015). In multivariate analysis, male gender, old age, heavy smoking, and a low intake of vitamin C were significant independent risk factors for COPD. A significant reduction of 76.7% in COPD risk was observed with a Q3 vitamin C intake compared to Q1 vitamin C intake (odds ratio, 0.233; 95% confidence interval, 0.094-0.576) in heavy smokers. CONCLUSION: This large-scale national study suggests that dietary vitamin C provides protection against COPD, independent of smoking history, in the general Korean population.

Gender Differences in Relations of Smoking Status, Depression, and Suicidality in Korea: Findings from the Korea National Health and Nutrition Examination Survey 2008-2012.

OBJECTIVE: As mental health problems may play an important role in initiating and maintaining cigarette smoking in females and there are an increasing number of female smokers, we evaluated the relationship between smoking status and mental health problems including depression and suicide ideation in women in Korea. METHODS: We analyzed the 5-year cumulative data (19 years of age or older, n=32,184) from the Korean National Health and Nutrition Examination Survey (KNHANES) conducted from 2008 to 2012. Logistic regression analyses were used to evaluate associations between cigarette smoking status and mental health parameters while controlling for potentially confounding variables. RESULTS: Among current smokers, females showed higher lifetime prevalence in having a depressive episode, a doctor-diagnosed major depression, a current diagnosis of depression, or receiving treatment for depression in comparison with males. In addition, females were more likely to report on having a depressive episode, suicidal ideation and attempts, and psychiatric counselling within the previous year, as compared to males. Female former smokers showed intermediate characteristics in parameters of mental health status within the previous year, ranking between lifetime non-smokers and the current smokers. CONCLUSION: Identifying the factors related to mental health status among current smokers can increase opportunities for an early intervention and help reduce the prevalence of smoking and increase smoking cessation rates particularly in females. Developing adaptive coping strategies other than smoking in female youth is potentially important in reducing the initiation of smoking.

Pulmonary Impairment in Tuberculosis Survivors: The Korean National Health and Nutrition Examination Survey 2008-2012.

OBJECTIVES: Pulmonary tuberculosis (TB) can affect lung function, but studies regarding long-term follow-up in patients with no sequelae on chest X-ray (CXR) have not been performed. We evaluated lung functional impairment and persistent respiratory symptoms in those with prior pulmonary TB and those with prior pulmonary TB with no residual sequelae on CXR, and determined risk factors for airflow obstruction. METHODS: We used data from adults aged ≥ 40 years from the annual Korean National Health and Nutrition Examination Surveys conducted between 2008 and 2012. P values for comparisons were adjusted for age, sex, and smoking status. RESULTS: In total of 14,967 adults, 822 subjects (5.5%) had diagnosed and treated pulmonary TB (mean 29.0 years ago). The FVC% (84.9 vs. 92.6), FEV1% (83.4 vs. 92.4), and FEV1/FVC% (73.4 vs. 77.9) were significantly decreased in subjects with prior pulmonary TB compared to those without (p < 0.001, each). In 12,885 subjects with no sequalae on CXR, those with prior pulmonary TB (296, 2.3%) had significantly lower FEV1% (90.9 vs. 93.4, p = 0.001) and FEV1/FVC% (76.6 vs. 78.4, p < 0.001) than those without. Subjects with prior pulmonary TB as well as subjects with no sequalae on CXR were more likely to experience cough and physical activity limitations due to pulmonary symptoms than those without prior pulmonary TB (p < 0.001, each). In total subjects, prior pulmonary TB (OR, 2.314; 95% CI, 1.922-2.785), along with age, male, asthma, and smoking mount was risk factor for airflow obstruction. In subjects with prior pulmonary tuberculosis, inactive TB lesion on chest x-ray (OR, 2.300; 95% CI, 1.606-3.294) were risk factors of airflow obstruction. CONCLUSION: In addition to subjects with inactive TB lesion on CXR, subjects with no sequelae on CXR can show impaired pulmonary function and respiratory symptoms. Prior TB is a risk factor for airflow obstruction and that the risk is more important when they have inactive lesions on chest X-ray. Hence, the patients with treated TB should need to have regular follow-up of lung function and stop smoking for early detection and prevention of the chronic airway disease.

Effect of Exposure to Second-Hand Smoke on the Quality of Life: A Nationwide Population-Based Study from South Korea.

BACKGROUND: Although exposure to second-hand smoke (SHS) has been associated with various medical conditions, only limited data are available on its association with health-related quality of life (HRQOL), particularly data obtained with the EQ-5D or EQ visual analogue scale (VAS). METHODS: This cross-sectional study evaluated 10,532 adult never-smokers who participated in the fifth Korea National Health and Nutrition Examination Survey. By using linear regression models to adjust for possible confounders and incorporating survey weights in analyses, the association between exposure to SHS and HRQOL-measured with the EQ-5D index and the EQ-VAS score-was evaluated. Data were further stratified by the amount of exposure time. RESULTS: After weighted analysis and adjustment, exposure to SHS was significantly associated with lower measures on the EQ-5D index (ß = -0.007, P = 0.005) and EQ-VAS score (ß = -1.936, P < 0.001). When comparing the unexposed group with the groups exposed <2h/day and ≥2h/day, exposure to a longer duration of SHS was significantly associated with lower scores on the EQ-5D index and the EQ-VAS score. CONCLUSION: In conclusion, exposure to SHS was associated with reduced HRQOL measured by the EQ-5D index and EQ-VAS score, revealing a dose-response relationship.

Seven-day continuous abstinence rate from smoking at 1, 2, or 3 years after the use of varenicline.

BACKGROUND: Varenicline, a selective partial agonist/antagonist of the α4ß2 nicotinic receptor, has proven effectiveness for smoking cessation by several randomized, controlled trials. Because few studies have evaluated the long-term efficacy of varenicline, we tried to evaluate the smoking status of varenicline users up to 3 years after the initial prescription of the drug. METHODS: We interviewed varenicline users who were prescribed the drug from June 2007 to May 2010 by telephone, from June 2010 to May 2011. RESULTS: One-hundred and thirty-three of 250 varenicline users (53.2%) were available for the survey. Seven-day continuous abstinence from smoking was adhered to by 17 of 39 respondents (43.6%) at 1 year, and 11 of 36 (30.6%) and 19 of 58 (32.8%) at 2 and 3 years since the first use of varenicline, respectively. Compared to current smokers, successful quitters were older (55.0 years vs. 49.9 years, p=0.01), had better compliance to the 12-week course (27.7 vs. 9.3%, p=0.01), and had taken varenicline longer (10.1 vs. 5.9 weeks, p=0.01). Fifty-four of 71 current smokers (76.1%) were willing to stop smoking in the near future. The preferred ways to cease smoking were will-power (48.1%), varenicline (25.9%), nicotine replacement therapy (11.1%), and others (14.9%). CONCLUSION: Smokers should be encouraged to stick to the proven way for recommended period of time for successful cessation of smoking.