Korea National Health Insurance Service Research Articles

Association between body mass index and the risk of atrial fibrillation and ischemic stroke according to age: a nationwide population-based cohort study

Abstract Background Atrial fibrillation (AF) and ischemic stroke (IS) are two significant cardiovascular diseases that confer an enormous healthcare burden. A limited study comprehensively evaluated the association between full ranges of body mass index (BMI), including underweight, and AF or IS risks, especially in the different age subgroups. Purpose We investigated the association between BMI and AF and IS incidence according to the Korean population's age groups. Methods This was a nationwide population-based cohort study using data from the Korea National Health Insurance Service, including 9 194 477 healthy adults who underwent a medical examination in 2009. We stratified the study population into three age subgroups: age 20–39 (young, 33.1%), age 40–64 (middle-aged, 56.3%), and age over 65 years (elderly, 10.6%). In each age group, the individuals were categorized based on BMI (kg/m2) into underweight (<18.5), normal (18.5 to <23), overweight (23 to <25), obese I (25 to <30), and obese II (≥30). The first occurrences of AF and IS were followed up until December 31, 2018. According to BMI in each age group, the risks of AF and IS were analyzed by Cox proportional hazards regression with 95% confidence intervals (CI) by adjusting age, sex, lifestyle behaviors, and comorbidities. Results Overall, both underweight and higher BMI were associated with an increased risk of AF and stroke across all age groups. The increased risk of AF for patients with obese II was slightly accentuated compared to patients with normal BMI in the young population than elderly population (hazard ratio [HR] 1.78, 95% CI 1.63–1.94 for age 20–39 years; HR 1.55, 95% CI 1.48–1.61 for age ≥65 years, respectively). For underweight individuals, however, the increased risk of AF became more prominent in the elderly: HR and 95% CI was 1.12 (1.07–1.17) in the age over 65 years old, and 1.05 (0.94–1.16) in the age 20–39. Regarding IS, the young group presented a considerable increment in the magnitude of HRs in both underweight and higher BMI groups. However, the association between the BMI and stroke risk became attenuated in the elderly: HRs and 95% CI in underweight and obese II individuals were 1.10 (0.93–1.30) and 2.223 (1.99–2.49) in the age 20–39 group, whereas 0.97 (0.93–1.01) and 1.03 (0.98–1.08) in the age over 65 years old. Conclusions Underweight as well as obesity was associated with increased risks of AF and IS in the general population. In both AF and IS, the gradient of risks according to BMI was apparent at young ages; thus, maintaining normal body weight should be warranted in early life. An interplay of several factors other than BMI may contribute to ischemic stroke in the old ages, requiring integrated risk management in older patients. Funding Acknowledgement Type of funding sources: None.

Particular matter influences the incidence of acute otitis media in children

Particulate matter (PM) is the main component of air pollution. Children are vulnerable to PM and acute otitis media (AOM), which is one of the most common diseases in children. However, studies on the relationship between AOM in children and PM are rare and their results are inconsistent. The aim of this study is to investigate the effect of PM on AOM in children on the basis of the Korea National Health Insurance service (NHIS) claims data. NHIS claim data from 2008 to 2015 was used to identify outpatient visits, antibiotic use to treat AOM, and demographic data. This data was combined with the data on PM2.5 (≤ 2.5 μm) and PM10 (≤ 10 μm according to its aerodynamic diameter) level extracted from air pollution data from Korean National Institute of Environmental Research for 16 administrative regions. The children with AOM were divided into three age groups (< 2, 2–4, 5–10 years). Generalized linear Poisson regression model was used to estimate the association between AOM and PM using daily counts of AOM and daily mean PM concentrations. It was adjusted to temperature, wind, humidity, season, year, age, and region. With an increase in PM2.5 of 10 μg/m3, the relative risk of OM increased by 4.5% in children under 2 years of age. The effect of PM2.5 was strongest influence on the day of exposure. The exposure to PM10 was related to the incidence of AOM on the day of exposure and the following seven days in all three age groups. The PM concentrations did not strongly affect either AOM duration or the use of antibiotics to cure AOM. The RR in the each lag day after exposure to PM10 was diverse according to the age groups. Regardless of PM size and children’s age, the PM levels are positively related to the incidence of AOM. Both PM2.5 and PM10 have the most adverse effects on children under 2 years of age and on the day of exposure.

Effects of menopausal hormone therapy on cardiovascular diseases and type 2 diabetes in middle-aged postmenopausal women: analysis of the Korea National Health Insurance Service Database.

Although menopausal hormone therapy (MHT) is the most effective treatment for menopausal symptoms, menopausal women hesitate to start MHT due to concerns about adverse events. Recently, however, it has been recommended to use it for appropriate patients who have been evaluated for baseline diseases, age, and timing of initiation. We aimed to investigate the association of MHT with cardiovascular diseases (CVDs) and type 2 diabetes among middle-aged postmenopausal women in Korea. Data were collected from the National Health Insurance Service database in Korea from 2002 to 2016. A total of 58,060 postmenopausal women (including 8,013 [13.8%] MHT users and 50,047 [86.2%] nonusers) were included. The time-dependent Cox regression model with a 1-year latency period was used to evaluate the hazard ratio (HR) and 95% confidence interval (CI) of the associations of MHT with CVDs and type 2 diabetes outcomes. Subgroup analyses by regimen type and cumulative duration were conducted. In the multivariate-adjusted model, MHT was not significantly associated with CVDs (HR = 1.085, 95% CI: 0.899-1.310) or type 2 diabetes (HR = 1.104, 95% CI: 0.998-1.221). Differential effects were not observed by regimen type, cumulative duration, and years since menopause subgroups. Sensitivity analyses also did not show adverse events by MHT on CVDs and type 2 diabetes. Although protective effects of MHT against CVDs or type 2 diabetes were not observed among postmenopausal women who had screened underlying diseases, our results may contribute to reducing the current concerns about the use of MHT for middle-aged postmenopausal women in Korea.

Association between Air Pollutants and Initial Hospital Admission for Ischemic Stroke in Korea from 2002 to 2013

ObjectivesThere is limited information regarding the association between air pollution exposure and stroke incidence. Therefore, this study aimed to assess the associations between short-term exposure to ambient air pollutants and initial hospital admission for ischemic stroke. Materials and MethodsFrom the Korea National Health Insurance Service–National Sample Cohort 2002–2013 database in South Korea, 55,852 first hospital admissions for ischemic stroke were identified. A generalized additive Poisson model was used to explore the association between air pollutants, including particulate matter, sulfur dioxide, nitrogen dioxide, and carbon monoxide and admissions for ischemic stroke. ResultsAll air pollutant models showed significant associations with ischemic stroke in the single lag model. In all air pollutant models excluding particulate matter 10 μm, a significant association was found between nitrogen dioxide exposure and initial admission for ischemic stroke after adjusting for other pollutants. An increment of 10 μg/m3 in nitrogen dioxide concentration at lag 0 and 14 days corresponded to a 0.259% (95% confidence interval, 0.231–0.287%) and 0.110% (95% confidence interval, 0.097–0.124) increase in initial admission for ischemic stroke, respectively. ConclusionsThe exposure-response relationship between nitrogen dioxide and initial admissions for ischemic stroke was approximately linear, with a sharper response at higher concentrations. Short-term exposure to nitrogen dioxide was positively associated with initial hospital admission for ischemic stroke.

Clinical impact of follow-up imaging on mortality in Korean breast cancer patients: A national cohort study.

BackgroundAs the incidence of breast cancer has increased and the survival rate has improved, supporting the optimal follow‐up strategy has become an important issue. This study aimed to evaluate follow‐up imaging usage after breast cancer surgery and the implications on mortality in Korea.MethodsThis study included 96,575 breast cancer patients diagnosed during 2002–2010 and registered in the Korea Central Cancer Registry, Statistics Korea, and Korean National Health Insurance Service. We evaluated the frequency of breast imaging (mammography and breast MRI) and systemic imaging for evaluating the presence of distant metastasis (chest CT, bone scan, and PET‐CT), and performed analyses to determine if they had an effect on mortality.ResultsThe median follow‐up period was 72.9 months (range: 12.0–133.3) and 7.5% of the patients died. Among all patients, 54.7%, 16.2%, 45.6%, and 8.5% received 3 or more mammograms, chest CTs, bone scans, and PET‐CTs within 3 years after surgery, respectively. Among patients who developed recurrence after 3 or more years, a comparison of overall mortality and breast‐cancer specific mortality according to the frequency of imaging by modality (<3 vs. ≥3) showed that only mammography had significantly reduced mortality (hazard ratio [HR]: 0.72, 95% CI: 0.61–0.84, p < 0.0001; HR: 0.72, 95% CI: 0.61–0.84; p < 0.0001).ConclusionsThis study showed that only frequent mammography reduced mortality and frequent imaging follow‐up with other modalities did not when compared to less frequent imaging. This finding provides supportive evidence that clinicians need to adhere to the current guidelines for surveillance after breast cancer surgery.

Association between long-term exposure to particulate matter and childhood cancer: Retrospective cohort study

BACKGROUND AND AIM: Particulate matter is known carcinogen, but its association with childhood cancer is inconsistent. The aim of the present study was to examine the association between air pollution and childhood cancer. METHODS: A retrospective cohort was constructed from claims database of the Korea National Health Insurance Service. Children who had been born in 7 metropolitan cities in Korea (Seoul, Incheon, Daejeon, Gwangju, Daegu, Busan, and Ulsan) from 2002 to 2012 were recruited and half of them were randomly selected. Children who were diagnosed with cancer within 5 years of birth were excluded. Monthly mean concentrations of particulate matter with aerodynamic diameter 10 μm (PM10) and other air pollutants (NO2, SO2, CO and O3) was calculated from AirKorea. Monthly mean concentrations of particulate matter with aerodynamic diameter 2.5 μm (PM2.5) was estimated with a concentration prediction model. The cumulative exposure was calculated by averaging monthly concentrations according to the subject's residential information. We constructed Cox proportional hazard model adjusting for potential confounders and O3 concentration. RESULTS:A total of 1,261,855 children (boys 641,704, girls 610,151) were included in the analysis. During the study period, 1,725 were newly diagnosed with cancer. Exposures to higher mean ambient PM2.5 and PM10 concentration increased the risk of childhood cancer. The hazard ratio of all cancers was 3.02 (95% confidence interval [CI]: 1.63, 5.59) and 1.04 (95% CI: 0.71, 1.45) for an increment of 10 μg/m3 of annual mean concentrations of PM2.5 and PM10, respectively. CONCLUSIONS:We observed significant positive association between particulate matter exposure and childhood cancer in a retrospective cohort of 1.2 million children. KEYWORDS: Particulate matter, Cancer, Children, Retrospective cohort

Association of gastroesophageal reflux disease with increased risk of chronic otitis media with effusion in adults: A nationwide population-based cohort study.

This study aimed to evaluate the risk of developing chronic otitis media with effusion (OME) in individuals with gastroesophageal reflux disease (GERD).A retrospective propensity score-matched cohort study was performed using data from the Korea National Health Insurance Service. The GERD group (n = 3532) included certain individuals who had been diagnosed with GERD between January 2002 and December 2005. A comparison control group (n = 14,128) was calculated by 1:4 propensity score matching considering age, sex, and comorbidities and year of enrollment. Each patient was monitored until 2013. Survival analysis, the Log-rank test, and Cox proportional hazard regression models were used to calculate the incidence, survival rate, and hazard ratio (HR) of chronic OME for each group.Among the 17,660 individuals included in the study population (53.2% men), the overall incidence of chronic OME during the 11-year follow-up was 1.84-fold higher in the GERD group than in the non-GERD group (1.8 vs 3.0 per 1000 person-year; adjusted HR 1.84; 95% confidence interval [CI], 1.46–2.31). Moreover, the adjusted HRs of developing chronic OME (allergic rhinitis, 1.69 [95% CI, 1.37–2.10]; asthma, 1.29 [95% CI, 1.02–1.64]; chronic rhinosinusitis, 1.61 [95% CI, 1.26–2.05]) were greater in study population with comorbidities.From long-term follow-up, the prevalence of chronic OME in adults was 1.84 times higher in the GERD group compared with the non-GERD group. Specifically, it found that allergic rhinitis, asthma, or chronic rhinosinusitis showed increase the risk of developing chronic OME than those without these conditions.

Effects of morbidity on smoking cessation: a national smoking cessation program

BackgroundIn smokers with chronic diseases, we examined the abstinence rates over 6 months and its affecting factors in the context of the Korea National Health Insurance Service (NHIS) smoking cessation program.MethodsTo identify 6-month abstinence, we extracted a sample of 15,017 participants using the multi-stage stratified cluster sampling method from the 359,047 individuals enrolled in the 2016 NHIS smoking cessation program and 1500 smokers responded to the telephone survey. From this group, 1245 individuals (48.50 ± 12.55 years; men 89.8%) were enrolled, as they had no missing information for confounding variables. We compared chronic disease distribution between participants and current smokers in the 2016 Korea National Health and Nutrition Examination Survey. We evaluated the factors affecting continuous abstinence rate (CAR) across patients with different chronic diseases: hypertension, diabetes mellitus (DM), dyslipidemia (DL), chronic obstructive pulmonary disease, and major depressive disorder (MDD).ResultsWhile participation of DM patients was high, the participation of DL patients was relatively low. The CAR over 6 months was 44.74%. The adjusted odds ratio (OR) for continuous abstinence over 6 months was significantly lower in the MDD group than in the no-MDD group (OR 0.43, 95% confidence interval [CI] 0.21 to 0.85). The factors of program completion (complete versus incomplete: OR 3.11, 95% CI 2.43 to 3.98), region (non-metropolitan areas versus Seoul metropolitan area: OR 1.28, 95% CI 1.01 to 1.61), and nicotine dependence (severe versus light or moderate: OR 0.64, 95% CI 0.50 to 0.83) were significantly associated with CAR.ConclusionsThe smoking cessation program was not actively recruiting smokers with chronic diseases. The CARs in each disease group were not different from those in the non-disease groups, except that the MDD group had a lower CAR over 6 months than the no-MDD group. Recruiting smokers with chronic diseases and improving their CARs depends on the careful identification of their characteristics.

Association of gastroesophageal reflux disease with increased risk of chronic otitis media with effusion in adults: A nationwide population-based cohort study.

This study aimed to evaluate the risk of developing chronic otitis media with effusion (OME) in individuals with gastroesophageal reflux disease (GERD).A retrospective propensity score-matched cohort study was performed using data from the Korea National Health Insurance Service. The GERD group (n = 3532) included certain individuals who had been diagnosed with GERD between January 2002 and December 2005. A comparison control group (n = 14,128) was calculated by 1:4 Propensity Score (PS) matching considering age, sex, and comorbidities and year of enrolment. Each patient was monitored until 2013. Survival analysis, the log-rank test, and Cox proportional hazard regression models were used to calculate the incidence, survival rate, and hazard ratio (HR) of chronic OME for each group.Among the 17,660 individuals included in the study population (53.2% male), the overall incidence of chronic OME during the 11-year follow-up was 1.84-fold higher in the GERD group than in the non-GERD group (1.8 vs 3.0 per 1000 person-year; adjusted HR 1.84; 95% confidence interval [CI], 1.46–2.31). Moreover, the adjusted HRs of developing chronic OME (allergic rhinitis, 1.69 [95% CI, 1.37–2.10]; asthma, 1.29 [95% CI, 1.02–1.64]; chronic rhinosinusitis, 1.61 [95% CI, 1.26–2.05]) were greater in study population with comorbidities.From long-term follow-up, the prevalence of chronic OME in adults was 1.84 times higher in the GERD group compared with the non-GERD group. Specifically, it found that allergic rhinitis, asthma, or chronic rhinosinusitis showed increase the risk of developing chronic OME than those without these conditions.

Detection of unknown ototoxic adverse drug reactions: an electronic healthcare record-based longitudinal nationwide cohort analysis

Ototoxic medications can lead to significant morbidity. Thus, pre-marketing clinical trials have assessed new drugs that have ototoxic potential. Nevertheless, several ototoxic side effects of drugs may remain undetected. Hence, we sought to retrospectively investigate the potential risk of ototoxic adverse drug reactions among commonly used drugs via a longitudinal cohort study. An electronic health records-based data analysis with a propensity-matched comparator group was carried out. This study was conducted using the MetaNurse algorithm for standard nursing statements on electronic healthcare records and the National Sample Cohort obtained from the South Korea National Health Insurance Service. Five target drugs capable of causing ototoxic adverse drug reactions were identified using MetaNurse; two drugs were excluded after database-based analysis because of the absence of bilateral hearing loss events in patients. Survival analysis, log-rank test, and Cox proportional hazards regression models were used to calculate the incidence, survival rate, and hazard ratio of bilateral hearing loss among patients who were prescribed candidate ototoxic drugs. The adjusted hazard ratio of bilateral hearing loss was 1.31 (1.03–1.68), 2.20 (1.05–4.60), and 2.26 (1.18–4.33) in cimetidine, hydroxyzine, and sucralfate users, respectively. Our results indicated that hydroxyzine and sucralfate may cause ototoxic adverse drug reactions in patients. Thus, clinicians should consider avoiding co-administration of these drugs with other well-confirmed ototoxic drugs should be emphasized.

A Deep Recurrent Neural Network-Based Explainable Prediction Model for Progression from Atrophic Gastritis to Gastric Cancer

Gastric cancer is the fifth most common cancer type worldwide and one of the most frequently diagnosed cancers in South Korea. In this study, we propose DeepPrevention, which comprises a prediction module to predict the possibility of progression from atrophic gastritis to gastric cancer and an explanation module to identify risk factors for progression from atrophic gastritis to gastric cancer, to identify patients with atrophic gastritis who are at high risk of gastric cancer. The data set used in this study was South Korea National Health Insurance Service (NHIS) medical checkup data for atrophic gastritis patients from 2002 to 2013. Our experimental results showed that the most influential predictors of gastric cancer development were sex, smoking duration, and current smoking status. In addition, we found that the average age of gastric cancer diagnosis in a group of high-risk patients was 57, and income, BMI, regular exercise, and the number of endoscopic screenings did not show any significant difference between groups. At the individual level, we identified that there were relatively strong associations between gastric cancer and smoking duration and smoking status.

Cost-effectiveness of open versus laparoscopic pancreatectomy: A population-based study using data from the Korea National Health Insurance Service

It has been shown that laparoscopic pancreatic resection (LPR) is comparable to open pancreatic resection (OPR). However, cost-effectiveness analysis of LPR is rare. We performed a population-based study on the cost-effectiveness of LPR versus OPR. Data of 9,255 patients who received pancreaticoduodenectomy (PD) (66.8%) and distal pancreatectomy (DP) (33.2%) from 2016 to 2018 were retrieved from the National Health Insurance Service. Events after pancreatectomy were categorized as no complications, intervention, reoperation, and death. Probabilities of each event and average cost during index admission (IA) and postoperative 1 year (Po1Y) were utilized to calculate incremental cost effectiveness ratio (ICER), the cost difference between two interventions divided by quality adjusted life year (QALY). QALY, a function of length and quality of life, was measured with utility values determined by researching literature. LPR was performed in 8.2% of PDs and 17.8% of DPs. For PD, LPR was associated with an increase of 0.0404 QALYs for IA and 0.0127 QALYs for Po1Y compared with OPR. Incremental cost was 421,917 KRW for IA and -1,860,579 KRW for Po1Y, leading to an ICER of 10,437,432 KRW per QALY gained for IA and -146,752,689 KRW per QALY gained for Po1Y. For DP, LPR improved 0.0909 QALYs for IA and 0.0469 QALYs for Po1A. Incremental cost was -1,632,107 KRW for IA and -7,730,674 KRW for Po1Y, leading to an ICER of -17,954,499KRW per QALY gained for IA and -164,990,346 KRW for Po1Y. Except initial higher cost of LPR, LPR was a cost-effective alternative to OPR for PD and DP.

Association between exercise habits and stroke, heart failure, and mortality in Korean patients with incident atrial fibrillation: A nationwide population-based cohort study.

There is a paucity of information about cardiovascular outcomes related to exercise habit change after a new diagnosis of atrial fibrillation (AF). We investigated the association between exercise habits after a new AF diagnosis and ischemic stroke, heart failure (HF), and all-cause death. This is a nationwide population-based cohort study using data from the Korea National Health Insurance Service. A retrospective analysis was performed for 66,692 patients with newly diagnosed AF between 2010 and 2016 who underwent 2 serial health examinations within 2 years before and after their AF diagnosis. Individuals were divided into 4 categories according to performance of regular exercise, which was investigated by a self-reported questionnaire in each health examination, before and after their AF diagnosis: persistent non-exercisers (30.5%), new exercisers (17.8%), exercise dropouts (17.4%), and exercise maintainers (34.2%). The primary outcomes were incidence of ischemic stroke, HF, and all-cause death. Differences in baseline characteristics among groups were balanced considering demographics, comorbidities, medications, lifestyle behaviors, and income status. The risks of the outcomes were computed by weighted Cox proportional hazards models with inverse probability of treatment weighting (IPTW) during a mean follow-up of 3.4 ± 2.0 years. The new exerciser and exercise maintainer groups were associated with a lower risk of HF compared to the persistent non-exerciser group: the hazard ratios (HRs) (95% CIs) were 0.95 (0.90-0.99) and 0.92 (0.88-0.96), respectively (p < 0.001). Also, performing exercise any time before or after AF diagnosis was associated with a lower risk of mortality compared to persistent non-exercising: the HR (95% CI) was 0.82 (0.73-0.91) for new exercisers, 0.83 (0.74-0.93) for exercise dropouts, and 0.61 (0.55-0.67) for exercise maintainers (p < 0.001). For ischemic stroke, the estimates of HRs were 10%-14% lower in patients of the exercise groups, yet differences were statistically insignificant (p = 0.057). Energy expenditure of 1,000-1,499 MET-min/wk (regular moderate exercise 170-240 min/wk) was consistently associated with a lower risk of each outcome based on a subgroup analysis of the new exerciser group. Study limitations include recall bias introduced due to the nature of the self-reported questionnaire and restricted external generalizability to other ethnic groups. Initiating or continuing regular exercise after AF diagnosis was associated with lower risks of HF and mortality. The promotion of exercise might reduce the future risk of adverse outcomes in patients with AF.

Humidifier Disinfectant Consumption and Humidifier Disinfectant-Associated Lung Injury in South Korea: A Nationwide Population-Based Study

Humidifier disinfectant (HD) is a household biocidal product used in humidifier water tanks to prevent the growth of microorganisms. In 2011, a series of lung injury cases of unknown causes emerged in children and pregnant women who had used HD in Korea. This study investigated changes in the nationwide number of cases of humidifier disinfectant-associated lung injury (HDLI) in concordance with nationwide HD consumption using data covering the entire Korean population. More than 25 kinds of HD products were sold between 1994 and 2011. The number of diagnosed HDLI, assessed by S27.3 (other injuries of lungs) of the Korea National Health Insurance Service (NHIS) data, sharply increased by 2005, subsequently decreased after 2005, and almost disappeared after 2011 in concordance with the annual number of HD sales. The number of self-reported HDLIs, assessed using data from all suspected HDLI cases registered in the Korea Ministry of Environment, changed with the annual number of HD sales, with a delay pattern, potentially induced by the late awareness of lung injury diseases. The present study suggests that changes in the nationwide annual consumption of HD products were consistent with changes in the annual number of HDLI cases in Korea.

Synergistic harmful interaction between sustained physical inactivity and hypertension/diabetes mellitus on the risk of all-cause mortality: a retrospective observational cohort study.

Hypertension, diabetes mellitus and physical inactivity can cause cardiovascular complications or premature death. However, it has not been clarified whether those major comorbidities and physical activity interact in affecting health outcomes. The aim of this study is to evaluate the potential interaction between temporal physical activity profiles and hypertension or diabetes mellitus on the risk for all-cause mortality. This study used Korea National Health Insurance Service (KNHIS) database and included about 6.5 million participants who underwent health screening in 2009 and 2011. Physical activity was evaluated as 2-year change based on self-reported survey using 7-day recall method, and grouped as remained active, inactive-to-active, active-to-inactive, or remained inactive. Participants were categorized into groups according to the presence of hypertension/diabetes mellitus. Outcome included all-cause mortality. In total, 6 554 082 participants (48.4 ± 13.3 years; 56.7% men) were included. During a median 6.4-year follow-up, 83 241 deaths occurred. Compared with the 'remained active' group, other groups had a higher mortality risk after adjustment for covariates [adjusted hazard ratio (aHR) 1.17, 95% CI 1.13-1.21 in the 'inactive-to-active' group, aHR 1.28, 95% CI 1.24-1.32 in the 'active-to-inactive' group, aHR 1.52, 95% CI 1.48-1.57 in the 'remained inactive' group). Hypertension and diabetes mellitus were significant effect modifiers in the association between physical activity and the risk of all-cause mortality (P for interaction <0.001). The harmful effects of persistent physical inactivity on all-cause mortality were the most obvious in those with both hypertension and diabetes mellitus among groups. Sustained physical inactivity was associated with increased risk of all-cause mortality in those with hypertension or diabetes mellitus more strongly than in those without. Physicians should emphasize sustained physical activity even more in patients with hypertension or diabetes mellitus.

Association between obstructive sleep apnea and thyroid cancer incidence: a national health insurance data study.

Little is known about the incidence of thyroid cancer in patients with obstructive sleep apnea (OSA). This study aimed to evaluate whether OSA is associated with the incidence of thyroid cancer based on the Korea National Health Insurance Service (KNHIS) database. This study was designed as a retrospective cohort data analysis of the KNHIS dataset. A total of 198,574 patients who were over 20years of age and had been newly diagnosed with OSA between 2007 and 2014 were enrolled. A control group of 992,870 individuals was selected based on propensity score matching by age and sex. The mean follow-up duration was 4.5 ± 2.3years. The primary endpoint was the incidence of newly diagnosed thyroid cancer. The hazard ratio (HR) for thyroid cancer incidence among OSA patients compared to the control was 1.72 (95% confidence interval [CI] 1.60-1.84) based on Model 1 (not adjusted by any covariate) and 1.64 (95% CI 1.53-1.76) based on Model 2 (adjusted by income level, diabetes, hypertension, and dyslipidemia). Thyroid cancer incidence was significantly higher in male patients (HR = 1.93, 95% CI 1.74-2.12) than female ones (HR = 1.39, 95% CI 1.26-1.54). When compared by age, the HR of thyroid cancer was higher in middle-aged (40 ≤ age < 65years) patients (HR = 1.68, 95% CI 1.55-1.83) than in young (20 ≤ age < 40years, HR = 1.53, 95% CI 1.32-1.77) or old (65 ≤ age, HR = 1.28, 95% CI 0.94-1.74) patients. OSA may increase the risk of developing thyroid cancer, especially in middle-aged men.

Changes in Cardiovascular Risk Factors and Cardiovascular Events in the Elderly Population.

BackgroundThis study examines changes in the ideal cardiovascular health (CVH) status and whether these changes are associated with incident cardiovascular disease (CVD) and mortality in the elderly Asian population.Methods and ResultsIn the Korea National Health Insurance Service–Senior cohort aged ≥60 years, 208 673 participants without prior CVD, including 109 431 who showed changes in CVH status, were assessed. The association of the changes in cardiovascular risk factors with incident CVD was assessed from 2004 to 2014 in the elderly (aged 60–74 years) and very elderly (≥75 years) groups. During the follow‐up period (7.1 years for CVD and 7.2 years for mortality), 19 429 incident CVD events and 24 225 deaths occurred. In both the elderly and very elderly participants, higher CVH status resulted in a lower risk of CVD and mortality. In the very elderly participants, compared with consistently low CVH, consistently high CVH (subhazard ratio, 0.41; 95% CI, 0.23–0.73) was associated with a lower risk of CVD. This trend was consistently observed in the elderly population. In the very elderly participants, total cholesterol level was not informative enough for the prediction of CVD events. In both the elderly and very elderly groups, body mass index and total cholesterol were not informative enough for the prediction of all‐cause mortality.ConclusionsIn both the elderly and very elderly Asian populations without CVD, a consistent relationship was observed between the improvement of a composite metric of CVH and the reduced risk of CVD. Body mass index and total cholesterol were not informative enough for the prediction of all‐cause mortality in both the elderly and very elderly groups.

Uvulopalatopharyngoplasty may decrease the incidence of Parkinson\u2019s disease associated with obstructive sleep apnea

The purpose of this study was to investigate whether the incidence of Parkinson’s disease (PD) is increased among patients with obstructive sleep apnea (OSA) and whether surgical treatment can prevent such an increase. This was a retrospective cohort study. We analysed the claims data from the Korea National Health Insurance Service. A total of 202,726 patients who were newly diagnosed with OSA between 2007 and 2014 were included. The patients were divided into two groups: patients who underwent uvulopalatopharyngoplasty (surgery group, n = 22,742) and those who did not (conservative group, n = 179,984). The control group (n = 1,013,630) was selected by propensity score matching. They were tracked until 31st December 2015. The hazard ratio of PD diagnosis (95% confidence interval) in the OSA group with respect to the control group was calculated using the Cox proportional hazard model. In the conservative group, the incidence of PD (hazard ratio 2.57 [2.32–2.85]) was significantly higher than that in the control group, while the incidence of PD in the surgery group was similar to that in the control group (hazard ratio 1.45 [0.89–2.22]). Patients with OSA are at an increased risk of developing PD, and uvulopalatopharyngoplasty may mitigate this risk.

Association of Preterm Birth with Depression and Particulate Matter: Machine Learning Analysis Using National Health Insurance Data.

This study uses machine learning and population data to analyze major determinants of preterm birth including depression and particulate matter. Retrospective cohort data came from Korea National Health Insurance Service claims data for 405,586 women who were aged 25–40 years and gave births for the first time after a singleton pregnancy during 2015–2017. The dependent variable was preterm birth during 2015–2017 and 90 independent variables were included (demographic/socioeconomic information, particulate matter, disease information, medication history, obstetric information). Random forest variable importance was used to identify major determinants of preterm birth including depression and particulate matter. Based on random forest variable importance, the top 40 determinants of preterm birth during 2015–2017 included socioeconomic status, age, proton pump inhibitor, benzodiazepine, tricyclic antidepressant, sleeping pills, progesterone, gastroesophageal reflux disease (GERD) for the years 2002–2014, particulate matter for the months January–December 2014, region, myoma uteri, diabetes for the years 2013–2014 and depression for the years 2011–2014. In conclusion, preterm birth has strong associations with depression and particulate matter. What is really needed for effective prenatal care is strong intervention for particulate matters together with active counseling and medication for common depressive symptoms (neglected by pregnant women).

Prevalence of Intracranial Aneurysm in Patients With Aortic Disease in Korea: A Nationwide Population-Based Study.

BackgroundPatients with aortic disease (AD) might have a higher prevalence of intracranial aneurysm (IA). The present study evaluated the prevalence of IA in patients with AD and identified potential risk factors of IA using nationwide representative cohort sample data.Methods and ResultsWe defined AD as both aortic dissections and aortic aneurysms. This study used a nationwide representative cohort sample from the Korea National Health Insurance Service–National Sample Cohort database from 1.1million patients. Using χ 2 or Fisher’s exact tests, the prevalence of the IA in patients with AD and potential risk factors for their concurrence were analyzed. The prevalence of IA in patients with AD was 6.8% (155/2285). The adjusted odds ratios (OR) for having concurrent IA in patients with AD was 3.809 (95% CI, 3.191–4.546; P<0.01). Patients with AD and hypertension were >19 times more likely to be affected by IA (adjusted OR, 18.679; 95% CI, 16.555–21.076; P<0.01). Patients with AD and diabetes mellitus, old age (>60 years), and male sex were >4, 3, and 2 times more likely to be affected by IA, respectively (adjusted OR, 4.291, 3.469, and 1.983, respectively; 95% CI, 3.914–4.704, 3.152–3.878, and 1.779–2.112, respectively). Subgroup analysis with socioeconomic status or disability revealed that the prevalence of IA was significantly higher in all groups.ConclusionsIn the current population‐based study, the prevalence of IA in patients with AD was quadrupled compared with that in the general population. Early IA screening might be considered among patients with AD for appropriate management.