Association between daily aspirin therapy and risk of hepatocellular carcinoma according to metabolic risk factor burden in non-cirrhotic patients with chronic hepatitis B.

BACKGROUND: Several studies have demonstrated chemopreventive effects of aspirin against hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). AIMS: To investigate the associations of aspirin use with risks of HCC, liver-related mortality, and major bleeding according to metabolic risk factor burden among non-cirrhotic patients with CHB METHODS: Using the Korean National Health Insurance Service database, we identified 282,611 non-cirrhotic adults with CHB. Data on obesity, diabetes, high blood pressure, and hypercholesterolemia were collected. Subjects were stratified into lower and higher metabolic risk groups (≤2 and ≥3 risk factors, respectively). Propensity score-matched cohorts of aspirin users and non-users were generated. Risks of HCC, liver-related death and major bleeding were analyzed. RESULTS: During the median follow-up of 7.4 years, positive associations between metabolic risk factor burden and outcomes were verified (all ptrend < 0.001). In the lower metabolic risk group (13,104 pairs), the association between aspirin use and HCC risk was not significant after multivariable adjustment (adjusted subdistribution hazard ratio [aSHR]: 0.93; 95% CI: 0.84-1.03); however, aspirin use was associated with elevated major bleeding risk (aSHR: 1.22; 95% CI: 1.08-1.39). In the higher metabolic risk group (2984 pairs), aspirin use was associated with reduced risks of HCC (aSHR: 0.72; 95% CI: 0.57-0.91) and liver-related mortality (aSHR: 0.69; 95% CI: 0.50-0.96) without an increase in risk of major bleeding (aSHR: 1.02; 95% CI: 0.79-1.32). CONCLUSIONS: Aspirin therapy was associated with reduced risks of HCC and liver-related death without excess risk of major bleeding, in non-cirrhotic patients with CHB who had a higher metabolic risk factor burden.

Item non-response imputation in the Korea National Health and Nutrition Examination Survey.

OBJECTIVES: The Korea National Health and Nutrition Examination Survey (KNHANES) is a public health survey that assesses individuals' health and nutritional status and monitors the prevalence of major chronic diseases. In general, sampling weights are adjusted for unit non-responses and imputation is conducted for item non-responses. In this study, we proposed strategies for imputing item non-responses in the KNHANES in order to improve the usefulness of data, minimize bias, and increase statistical power. METHODS: After applying logical imputation, we adopted 2 separate imputation methods for each variable type: unweighted sequential hot-deck imputation for categorical variables and sequential regression imputation for continuous variables. For variance estimation, multiple imputations were applied to the continuous variables. To evaluate the performance of the proposed strategies, we compared the marginal distributions of imputed variables and the results of multivariable regression analysis for the complete-case data and the expanded data with imputed values, respectively. RESULTS: When comparing the marginal distributions, most non-responses were imputed. The multivariable regression coefficients presented similar estimates; however, the standard errors decreased, resulting in statistically significant p-values. The proposed imputation strategies may cope with the loss of precision due to missing data, thus enhancing statistical power in analyses of the KNHANES by providing expanded data with imputed values. CONCLUSIONS: The proposed imputation strategy may enhance the utility of data by increasing the number of complete cases and reducing the bias in the analysis, thus laying a foundation to cope with the occurrence of item non-responses in further surveys.

Data collection framework for electronic medical record-based real-world data to evaluate the effectiveness and safety of cancer drugs: a nationwide real-world study of the Korean Cancer Study Group.

Background: Electronic medical records (EMRs) have the highest value among real-world data (RWD). The aim of the present study was to propose a data collection framework of EMR-based RWD to evaluate the effectiveness and safety of cancer drugs by conducting a nationwide real-world study based on the Korean Cancer Study Group. Methods: We considered all patients who received ramucirumab plus paclitaxel (RAM/PTX) for gastric cancer and trastuzumab emtansine (T-DM1) for breast cancer at relevant institutions in South Korea. Standard operating procedures for systematic data collection were prospectively developed. Investigator reliability was evaluated using the concordance rate between the recommended input value for representative fictional cases and the input value of each investigator. Reliability of collected data was evaluated twice during the study period at three institutions randomly selected using the concordance rate between the previously collected data and data collected by an independent investigator. The reliability results of the investigators and collected data were used for revision of the electronic data capture system and site training. Results: Between the starting date of medical insurance coverage and December 2018, a total of 1063 patients at 56 institutions in the RAM/PTX cohort and 824 patients at 60 institutions in the T-DM1 cohort were included. Mean investigator reliability in the RAM/PTX and T-DM1 cohorts was 73.5% and 71.9%, respectively. Mean reliability of collected data in the RAM/PTX and T-DM1 cohort was 90.0% for both cohorts in the first analysis and 89.0% and 84.0% in the second analysis, respectively. Mean missing values of the RAM/PTX and T-DM1 cohorts at the time of simulation of fictional cases and final data analysis decreased from 20.7% to 0.46% and from 18.5% to 0.76%, respectively. Conclusion: This real-world study provides a framework that ensures relevance and reliability of EMR-based RWD for evaluating the effectiveness and safety of cancer drugs.

Effectiveness of Lenvatinib Versus Sorafenib for Unresectable Hepatocellular Carcinoma in Patients with Hepatic Decompensation.

BACKGROUND/AIM: Lenvatinib and sorafenib are currently available to treat patients with advanced hepatocellular carcinoma (HCC). However, since the clinical trials evaluating the efficacy of lenvatinib and sorafenib included only patients with Child-Pugh class A, little is known about the effectiveness of the treatments in patients with hepatic decompensation. We compared the effectiveness of lenvatinib and sorafenib in decompensated patients with unresectable HCC. METHODS: Consecutive patients who were classified as Child-Pugh class B or C and received lenvatinib or sorafenib as first-line systemic therapy for unresectable HCC between November 2018 and April 2020 at a tertiary referral center were included in this retrospective study. The primary outcome was overall survival (OS), and the secondary outcomes were progression-free survival (PFS), time-to-progression, best overall tumor response, and safety profiles. RESULTS: Among 94 patients, 34 received lenvatinib and 60 received sorafenib. The median OS was 4.1 months (95% confidence interval [CI], 2.9-5.2): 4.2 months (95% CI, 2.9-5.3) for lenvatinib and 4.1 months (95% CI, 2.7-6.4) for sorafenib. The treatment regimen was not associated with significant improvement in OS after adjusting for covariables (adjusted hazard ratio [aHR], 0.92; 95% CI, 0.54-1.54; P = 0.74). The treatment regimen was not an independent predictor of PFS (lenvatinib vs. sorafenib; aHR, 0.77; 95% CI, 0.48-1.24; P = 0.28). HRs were maintained even after balancing with the inverse probability treatment weighting method. Objective response rates were 11.8% and 6.7% in patients receiving lenvatinib and sorafenib, respectively (P = 0.45). Ten patients in both groups (five in the lenvatinib group and five in the sorafenib group) underwent dose modification due to adverse events, and significant difference was not observed between the treatment groups (P = 0.49). CONCLUSION: The effectiveness of lenvatinib and sorafenib was comparable for the treatment of unresectable HCC in decompensated patients.

Aspirin use and risk of hepatocellular carcinoma in patients with chronic hepatitis B with or without cirrhosis.

BACKGROUND AND AIMS: Studies on differential effect of aspirin therapy on HCC risk across the spectrum of liver diseases are lacking. We investigated the association between aspirin use and risks of HCC, liver-associated death, and major bleeding in chronic hepatitis B (CHB) patients with or without cirrhosis. APPROACH AND RESULTS: We identified 329,635 eligible adults with CHB from 2007 through 2017, using the Korean National Health Insurance Service database, including patients who received aspirin for ≥90 consecutive days (n = 20,200) and patients who never received antiplatelet therapy (n = 309,435). Risks of HCC, liver-associated mortality, and major bleeding were estimated in a propensity-score-matched cohort (19,003 pairs), accounting for competing risks. With a median follow-up of 6.7 years, 10-year cumulative incidence of HCC was 9.5% in the aspirin-treated group and 11.3% in the untreated group (adjusted subdistribution hazard ratio [aSHR], 0.85; 95% CI, 0.78-0.92). However, among patients with cirrhosis (2479 pairs), an association of aspirin use with HCC risk was not evident (aSHR, 1.00; 95% CI, 0.85-1.18). Cirrhosis status had a significant effect on the association between aspirin use and HCC risk (pinteraction , n = 0.04). Aspirin use was also associated with lower liver-associated mortality (aSHR, 0.80; 95% CI, 0.71-0.90). Moreover, aspirin use was not associated with major bleeding risk (aSHR, 1.09; 95% CI, 0.99-1.21). CONCLUSIONS: Aspirin use was associated with reduced risks of HCC and liver-associated mortality in adults with CHB. Cirrhosis status had a substantial effect on the association between aspirin use and HCC risk.

Clinical Efficacy of Ruxolitinib in Patients with Myelofibrosis: A Nationwide Population-Based Study in Korea.

Previous studies have reported the survival benefit after ruxolitinib treatment in patients with myelofibrosis (MF). However, population-based data of its efficacy are limited. We analyzed the effects of ruxolitinib in MF patients with data from the Korean National Health Insurance Database. In total, 1199 patients diagnosed with MF from January 2011 to December 2017 were identified, of which 731 were included in this study. Patients who received ruxolitinib (n = 224) were matched with those who did not receive the drug (n = 507) using the 1:1 greedy algorithm. Propensity scores were formulated using five variables: age, sex, previous history of arterial/venous thrombosis, and red blood cell (RBC) or platelet (PLT) transfusion dependence at the time of diagnosis. Cox regression analysis for overall survival (OS) revealed that ruxolitinib treatment (hazard ratio (HR), 0.67; p = 0.017) was significantly related to superior survival. In the multivariable analysis for OS, older age (HR, 1.07; p < 0.001), male sex (HR, 1.94; p = 0.021), and RBC (HR, 3.72; p < 0.001) or PLT (HR, 9.58; p = 0.001) transfusion dependence were significantly associated with poor survival, although type of MF did not significantly affect survival. Considering evidence supporting these results remains weak, further studies on the efficacy of ruxolitinib in other populations are needed.

Trends in Pediatric Thyroid Cancer Incidence, Treatment, and Clinical Course in Korea During 2004-2016: A Nationwide Population-Based Study.

Background: The incidence of thyroid cancer has increased worldwide. We investigated nationwide trends in the incidence and treatment course of pediatric thyroid cancer in South Korea. Methods: Using the National Health Information Database, we analyzed 1580 patients (324 males) <20 years of age diagnosed with thyroid cancer during 2004-2016 in South Korea. The annual percentage change (APC) in the age-standardized incidence rate (ASR) was calculated by joinpoint regression analysis. The initial treatment modality was categorized as either surgery only or surgery with radioactive-iodine treatment (surgery+RAIT), and we defined new treatment events as reoperations or additional RAITs among 1464 patients followed up for ≥12 months. Results: During 2004-2016, the mean ASR per 100,000 person-years increased from 0.6 [confidence interval; CI 0.5-0.8] to 0.9 [CI 0.8-1.1], with a mean APC of 4.0% [CI 1.8-6.2]. The ASRs (APCs) among 0-9-, 10-14-, 15-17-, and 18-19-year olds were 0.07 (9.9% [CI 0.08-20.7]), 0.6 (4.6% [CI 0.2-9.2]), 2.2 (3.9 [CI 1.7-6.0]), and 4.2 (3.5% [CI 0.9-6.2]), respectively. The lobectomy and lymph-node-dissection rates increased (from 18.5% to 33.6%, p = 0.0014; and from 29.6% to 84.5%, p < 0.001; respectively), but the RAIT rate decreased (67.9-39.7%, p < 0.001) during the study period. During a median 6.3-year follow-up, two patients died. New treatment events occurred in 56 (10.7%) of patients in the initial surgery-only group (n = 523). In the initial surgery+RAIT group (n = 941), 316 patients received two or more RAITs within 2 years, and 80 (12.8%) of the remaining 625 patients underwent new treatment events. In the surgery+RAIT subgroup, the event-free survival rate was lower in 0-14-year olds than in 18-19-year olds (hazard ratio 2.5 [CI 1.4-4.4]). Conclusions: The pediatric thyroid cancer incidence increased from 2004 to 2012 in South Korea. The lobectomy and lymph-node-dissection rates increased, but the RAIT rate decreased. The higher risk for new treatment events in patients younger than 15 years requiring initial RAIT may be linked to advanced stage at diagnosis, and it needs to be further evaluated.

Association of Metabolic Risk Factors With Risks of Cancer and All-Cause Mortality in Patients With Chronic Hepatitis B.

BACKGROUND AND AIMS: Long-term antiviral therapy can effectively suppress viral replication and improve clinical outcomes in patients with chronic hepatitis B (CHB), but it cannot eliminate risk of HCC. We investigated the association of metabolic risk factors with the risks of cancer and all-cause mortality in patients with CHB. APPROACH AND RESULTS: This nationwide population-based study from the Korean National Health Insurance Service database consisted of adults with CHB who underwent health examinations from 2007 through 2012. We collected baseline data on metabolic risk factors, including obesity, high blood pressure, hypercholesterolemia, and diabetes. The risks of developing HCC, non-HCC cancer, and overall death were analyzed according to the metabolic risk profile. The study population composed of 317,856 patients (median age, 46 years [interquartile range, 37-54 years]; 219,418 men [69.0%]) had 2,609,523.8 person-years of follow-up. A total of 18,850 HCCs, 22,164 non-HCC cancers, and 15,768 deaths were observed during a median follow-up period of 8.5 years. The metabolic risk factor burden was positively associated with the risks of HCC, non-HCC cancer, and all-cause mortality (all P < 0.0001 for trend). Patients with ≥3 metabolic risk factors, compared with those without metabolic risk factors, showed adjusted hazard ratios of 1.23 (95% CI, 1.16-1.31) for HCC, 1.34 (95% CI, 1.27-1.41) for non-HCC cancer, and 1.31 (95% CI, 1.23-1.39) for all-cause mortality. Among patients receiving antiviral therapy for over 5 years, the risk-increasing association of the sum of metabolic risk factors with the risks of HCC and overall death was consistent. CONCLUSION: The metabolic risk factor burden was associated with increased risks of HCC, non-HCC cancer, and all-cause mortality in patients with CHB.

Trends in the Diagnosis and Treatment of Patients with Medullary Thyroid Carcinoma in Korea.

BACKGROUND: Thyroid cancer is becoming increasingly common worldwide, but little is known about the epidemiology of medullary thyroid carcinoma (MTC). This study investigated the current status of the incidence and treatment of MTC using Korean National Health Insurance Service (NHIS) data for the entire Korean population from 2004 to 2016. METHODS: This study included 1,790 MTC patients identified from the NHIS database. RESULTS: The age-standardized incidence rate showed a slightly decreasing or stationary trend during the period, from 0.25 per 100,000 persons in 2004 to 0.19 in 2016. The average proportion of MTC among all thyroid cancers was 0.5%. For initial surgical treatment, 65.4% of patients underwent total thyroidectomy. After surgery, external-beam radiation therapy (EBRT) was performed in 10% of patients, a proportion that increased from 6.7% in 2004 to 11.0% in 2016. Reoperations were performed in 2.7% of patients (n=49) at a median of 1.9 years of follow-up (interquartile range, 1.2 to 3.4). Since November 2015, 25 (1.4%) patients with MTC were prescribed vandetanib by December 2016. CONCLUSION: The incidence of MTC decreased slightly with time, and the proportion of patients who underwent total thyroidectomy was about 65%. EBRT, reoperation, and tyrosine kinase inhibitor therapy are additional treatments after initial surgery for advanced MTC in Korea.

Greenness, civil environment, and pregnancy outcomes: perspectives with a systematic review and meta-analysis.

BACKGROUND: Various maternal conditions, especially in utero conditions and prenatal exposure to environments with air pollution and greenness, have been reviewed to address the enhancement and prevention of susceptibility to health risks, including low birthweight, preterm delivery, and preeclampsia. This study aimed to qualitatively and quantitatively investigate the associations between pregnancy outcomes and the characteristics of surrounding living environment, including greenness, air pollution, and civilization. METHODS: A secondary search of the MEDLINE, EMBASE, Cochrane Library, K-eArticles, and CINAHL databases was conducted without language restrictions to identify the relevant publications from the time of inception of the databases to April 2019. RESULTS: A total of 89 studies were identified, and 10 were included in the quantitative synthesis. The greenness of the environment within 100-, 250- and 500-m buffers, after adjusting for the air quality and civilization factors, was weakly but positively associated with birthweight. The pooled regression slope was 0.00134 (95% confidence interval [CI], 0.000, 0.0020). The greenness of the environment was also associated with a significant decrease in the incidence of poor pregnancy outcomes, namely, low birthweight, small for gestational age (odds ratio [OR] 0.94; 95% CI, 0.92, 0.97), and preterm delivery (OR 0.98; 95% CI, 0.97, 0.99). CONCLUSIONS: The greenness of the environment had a positive effect on the pregnancy outcomes, despite poor air quality and civilization. Following urbanization, planning for greenness management, environmental medicine, and public health is important and thus should be proposed as preventive methods as way of increasing birthweight and life expectancy.

Nationwide study of paroxysmal nocturnal hemoglobinuria in South Korea: paradox of eculizumab.

Eculizumab is effective in managing patients with paroxysmal nocturnal hemoglobinuria (PNH). In South Korea, the financial support for eculizumab therapy is extended by the National Health Insurance Services (NHIS) only to patients with high-risk PNH for approximately 10 years. In this study, we performed a nationwide analysis of the real-world efficacy of eculizumab therapy in patients diagnosed with PNH between January 1, 2002, and December 31, 2016, by using the NHIS database. Patients treated with eculizumab (the eculizumab-treated group) exhibited a significantly higher survival rate than patients not treated with eculizumab (the eculizumab-untreated group), with 4-year survival rates after propensity score matching of 98.31% and 79.67%, respectively (p = 0.0489). The mean red blood cell (RBC) transfusion units per 12 months after eculizumab therapy were significantly lower than that before eculizumab therapy (5.75 units vs. 12.28 units, p < 0.0001). The median time for the first transfusion in the eculizumab-treated group was significantly longer than that in the eculizumab-untreated group. The 4-year transfusion-independence rate for the eculizumab-treated group was significantly higher than that for the eculizumab-untreated group (20.81% vs. 10.24%, p = 0.078). There was no significant difference between the two groups in the incidence of new documented complications related to PNH. In conclusion, eculizumab therapy for patients with high-risk PNH may effectively improve the survival rate and reduce the transfusion requirement. Paradoxically, eculizumab-treated patients with severe PNH exhibit a higher survival rate than eculizumab-untreated patients with less severe PNH.

Prevalence and complications of nonsurgical hypoparathyroidism in Korea: A nationwide cohort study.

OBJECTIVE: The risk of complications of nonsurgical hypoparathyroidism in Asia is unclear. We estimated the prevalence and risk of complications in patients with nonsurgical hypoparathyroidism. METHODS: We performed a retrospective cohort study using a nationwide claims database from 2005 to 2016. Among the entire Korean population, we identified 897 patients diagnosed with nonsurgical hypoparathyroidism during 2005-2015. We selected 210 patients with nonsurgical hypoparathyroidism during 2005-2008 who had no complications at baseline and followed them to 2016. Control subjects (n = 2075) were matched using propensity scores based on age, sex, and comorbid disease with a 1:10 ratio and monitored until 2016. RESULTS: The age-standardized prevalence of nonsurgical hypoparathyroidism was 0.2 cases per 100,000 persons in 2005. During a mean follow-up period of 9.5 years, patients with nonsurgical hypoparathyroidism had a higher risk of cardiovascular disease, especially arrhythmia (hazard ratio [HR], 2.03; 95% confidence interval [CI], 1.11-3.70) and heart failure (HR, 2.43; 95% CI, 1.22-4.83). The risk of vertebral fracture was higher in patients than in controls (HR, 2.27; 95% CI, 1.09-4.72). Patients had a significantly increased risk of renal disease (HR, 2.57; 95% CI, 1.56-4.21), seizure (HR, 5.74; 95% CI, 3.34-9.86), depression and bipolar disease (HR, 1.82; 95% CI, 1.30-2.56), and cataract (HR, 1.90; 95% CI, 1.30-2.79) compared with controls. CONCLUSIONS: The prevalence of nonsurgical hypoparathyroidism was very low in Korea but was associated with a higher risk of incident cardiovascular disease and vertebral fracture as well as known complications including renal disease, seizure, and cataract.

Epidemiology and Prognosis of Pheochromocytoma/Paraganglioma in Korea: A Nationwide Study Based on the National Health Insurance Service.

BACKGROUND: Pheochromocytomas and paragangliomas (PPGLs) are rare endocrine tumors originating from chromaffin cells. PPGLs are associated with a high mortality rate and several complications. To date, no epidemiological studies have been conducted on PPGLs in Asia. This study aimed to investigate the epidemiology and prognosis of PPGLs in Korea using nationwide data. METHODS: Using the National Health Insurance Service Database, subjects with a principal diagnosis of PPGLs on two or more occasions between 2003 and 2014 who satisfied the operational definition of PPGLs were included. Incidence, prevalence, complications, metastasis, and mortality were investigated. RESULTS: In total, 1048 subjects with a mean age of 47.6±16.1 years were included. There was no sex preponderance. The overall prevalence of PPGLs was 2.13 per 100,000 persons, and the overall age-standardized incidence rate was 0.18 per 100,000 person-years. Malignant PPGLs accounted for 17.7% (185 of 1,048) of cases, and 94 subjects exhibited metastasis at the time of diagnosis. Among initially non-metastatic PPGLs, 9.5% (nine of 954) eventually metastasized after a mean duration of 78.1±41.4 months. The 5-year survival rates for non-metastatic and metastatic PPGLs at diagnosis were 97% and 84%, respectively. Multivariable Cox regression models adjusted for covariates showed that metastatic PPGLs were associated with a 2.40-fold higher risk of mortality than non-metastatic PPGLs (95% confidence interval, 1.38 to 4.17; P=0.002). CONCLUSION: PPGLs are rare in Korea, and the prognosis of these endocrine tumors varies depending on whether they are benign or malignant. This epidemiological study paves the way for further research on PPGLs.

Mental health according to sleep duration in stroke survivors: A population-based nationwide cross-sectional study.

AIM: Many stroke survivors experience sleep disorders, and are at risk of severe depression and stress. This study examined the association between mental health and sleep duration among Korean stroke survivors. METHODS: This cross-sectional study analyzed data from the Korea National Health and Nutrition Examination Surveys V (2010-2012) and VI (2013). The nationally representative sample included 504 adults aged ≥19 years. RESULTS: The odds ratio for suicidal ideation was 2.71 (95% confidence interval 1.11-6.60) for stroke survivors who slept <5 h as compared with stroke survivors who slept between 6 and 8 h. Although stress and depression did not differ according to sleep duration, suicidal ideation did. CONCLUSIONS: Sleep duration should be considered as a possible leverage point for preventing suicidal ideation among stroke survivors, and health promotion programs that promote and educate survivors about the importance of appropriate sleep duration are required. Geriatr Gerontol Int 2019; ••: ••-••.

Association between quality of life and sleep time among community-dwelling stroke survivors: Findings from a nationally representative survey.

AIM: This study aimed to examine the association between quality of life and sleep time among adult stroke survivors. METHODS: This cross-sectional study used nationally representative data from the Korea National Health and Nutrition Examination Survey (2010-2013), and analyzed data on 504 adult stroke survivors. RESULTS: Findings showed that stroke survivors' daily sleep time significantly varied by sex (P < 0.001), education (P = 0.006) and body mass index (P = 0.012). The EuroQOL-5 Dimension index (P < 0.001), and its dimensions of mobility (P = 0.011), usual activities (P < 0.001) and pain/discomfort (P = 0.005) showed significant differences among people with different sleep times. In the final model, after adjusting for covariates, respondents who slept ≤5 h had odds ratios of 1.82 (95% confidence interval 1.05-3.16) for usual activities and 1.95 (95% confidence interval 1.16-3.27) for pain/discomfort compared with respondents who slept 6-8 h. Respondents who slept ≥9 h had an odds ratio of 3.03 (95% confidence interval 1.43-6.43) for usual activities compared with those who slept 6-8 h. Adjusted means for the EuroQOL-5 Dimension index showed significant differences: 0.76 for ≤5 h, 0.85 for 6-8 h and 0.75 for ≥9 h (P = 0.001). CONCLUSIONS: Our findings show an association between quality of life and sleep time among adult stroke survivors. Sleep time should be considered in efforts to improve stroke survivors' quality of life, including education and interventions that encourage 6-8 h of sleep. Geriatr Gerontol Int 2019; 19: 1226-1230.

Association between smoking type and prevalence of atopic dermatitis and asthma in men and women.

AIM: This study aimed to examine the association between smoking type and the prevalence of atopic dermatitis and asthma in men and women. BACKGROUND: Cases of allergic diseases have been steadily increasing worldwide. Smoking is associated with serious diseases. Only a few studies have assessed the association between smoking and atopic dermatitis and asthma in adults, and gender difference studies are scarce despite a significant difference in smoking rates. METHODS: We conducted a secondary cross-sectional analysis of 17 886 adults with atopic dermatitis and 17 889 with asthma aged ≥19 years, using raw data from the Fifth Korea national Health and Nutrition Examination Survey (2010-2012). RESULTS: The prevalence of atopic dermatitis in men was not associated with active or passive smoking, whereas asthma prevalence in men was associated with indoor passive smoking exposure at home. We found that atopic dermatitis prevalence in women was associated with current smoking status, whereas asthma prevalence in women was associated with the presence of an indoor daily smoker at home and indoor passive smoking exposure at home. CONCLUSION: Asthmatic adults should be informed of the hazards of passive smoking, and women with atopic dermatitis should in particular be dissuaded from smoking.