Association between menopausal hormone therapy and the risk of gastric cancer: A Korean nationwide population-based cohort study

OBJECTIVE

Gastric cancer (GC) is more common in men than women, but also more common among postmenopausal than premenopausal women. The protective effect of reproductive hormones against GC remains unclear. Therefore, we evaluated the association between menopausal hormone therapy (MHT) and the risk of GC in women.

METHODS

We investigated the national cohort data of women aged over 40 years who underwent health checkups by the Korean National Health Insurance Service in 2009. After excluding individuals with missing data and those previously diagnosed with cancer, 1,354,621 postmenopausal women were included and divided into groups according to their MHT history. We followed the study population until 2018 and analyzed the hazard ratios (HR) with 95 % confidence intervals (CIs) for the incidence rate of GC in a multivariate adjusted model.

RESULTS

The number of women with and without a history of MHT was 214,723 (15.9 %) and 1,139,898 (84.1 %), respectively. During the mean 8.32 ± 0.8 years of follow-up, a total of 12,496 GC cases developed in the study population (10,962 MHT non-users; 1534 MHT users). In the adjusted model, MHT was associated with a 12 % decrease in the development of GC relative to non-use of MHT (HR 0.88; 95 % CI 0.83-0.93). Exposure to MHT for >2 years was linked to a reduction in GC risk, particularly when initiated before the age of 50, giving a 45 % risk reduction.

CONCLUSIONS

According to our large-scale prospective national cohort study, exogenous MHT is associated with a decreased risk of GC in postmenopausal women.

Prevalence and impact of depression and anxiety among older myocardial infarction survivors: A nationwide cohort study

BACKGROUND

Depression and anxiety may be significant prognostic factors after myocardial infarction (MI). Thus, we investigated depression and anxiety prevalence among older MI survivors and their impact on mortality, stroke, and recurrent MI.

METHODS

This population-based cohort study used the Korean National Health Insurance Service database for data concerning individuals aged 66 years who participated in the National Screening Program from 2009 to 2016. Overall, 11,721 individuals with MI history and 58,605 age- and sex-matched controls were included and followed up until 2019. The presence of depression and anxiety was assessed 2 years before and after participation in the program. Mortality and major adverse outcomes, defined as a composite outcome comprising mortality, stroke, and recurrent MI, were analyzed.

RESULTS

Depression and anxiety prevalence among MI survivors was 20.4 % and 30.3 %, respectively. Crude odds ratios for depression and anxiety, compared with the control group, were 1.207 (1.148-1.269) and 1.078 (1.032-1.126), respectively. During the follow-up, individuals with depression, anxiety, or both showed increased hazard ratios (HRs) for mortality and major adverse outcomes; after adjustments, their HRs were 1.442 (1.182-1.759), 1.129 (0.960-1.328), and 1.498 (1.263-1.776), respectively, for mortality and 1.505 (1.289-1.758), 1.158 (1.021-1.314), and 1.530 (1.337-1.751), respectively, for major adverse outcomes.

LIMITATIONS

Although this was a nationwide cohort study, the MI, depression, and anxiety diagnoses were based on diagnostic codes.

CONCLUSIONS

Higher depression and anxiety prevalence was observed among older MI survivors. Depression and anxiety occurrence correlated with increased adverse clinical outcomes after adjustments.

Cumulative exposure to impaired fasting glucose and gastrointestinal cancer risk: A nationwide cohort study

BACKGROUND

Impaired fasting glucose (IFG) is associated with the risk of various cancers, but the cumulative effect of IFG on gastrointestinal cancer risk remains unclear. This study evaluated the association between the cumulative exposure to IFG and gastrointestinal cancer risk.

METHODS

The authors extracted data from the Korean National Health Insurance Service and health examination data sets. Among individuals ≥40 years old who were free of diabetes or cancer, 1,430,054 who underwent national health examinations over 4 consecutive years from 2009 to 2012 were selected and followed up until gastrointestinal cancer diagnosis, death, or December 31, 2019. The IFG exposure score (range, 0-4) was based on the number of IFG diagnoses over 4 years.

RESULTS

The median follow-up duration was 6.4 years. Consistent normoglycemia for 4 years was found in 44.3% of the population, whereas 5.0% had persistent IFG and 50.7% had intermittent IFG. Compared to the group with an IFG exposure score of 0, groups with IFG exposure scores of 1, 2, 3, and 4 had a 5%, 8%, 9%, and 12% increased risk of gastrointestinal cancer, respectively (score 1: adjusted hazard ratio [aHR], 1.05; 95% confidence interval [CI], 1.01-1.08; score 2: aHR, 1.08; 95% CI, 1.04-1.12; score 3: aHR, 1.09; 95% CI, 1.05-1.14; score 4: aHR, 1.12; 95% CI, 1.06-1.19). Persistent IFG exposure was also associated with higher risks of individual cancer types (colorectum, stomach, pancreas, biliary tract, and esophagus).

CONCLUSIONS

Cumulative exposure to IFG is associated with an increased risk of developing gastrointestinal cancer, in a dose-dependent manner.

PLAIN LANGUAGE SUMMARY

Hyperglycemia, including both diabetes and prediabetes, has been associated with an increased risk of various cancers. However, the cumulative effect of impaired fasting glucose on the risk of developing gastrointestinal cancer remains unclear. A frequent diagnosis of impaired fasting glucose was dose-dependently associated with a higher risk of developing overall gastrointestinal cancer. Furthermore, risks of individual cancer types increased with persistent impaired fasting glucose. Early detection of hyperglycemia and strict glycemic control can lower the risk of gastrointestinal cancer by reducing hyperglycemic burden. Additionally, for some individuals, lifestyle changes such as managing metabolic syndrome or abstaining from alcohol may also be helpful.

The risk of open angle glaucoma in young adults with allergic diseases: a Nationwide cohort study

This study investigated the potential associations between allergic diseases (asthma, allergic rhinitis, and atopic dermatitis) and the development of primary open-angle glaucoma. We utilized authorized data from the Korean National Health Information Database (KNHID), which provides comprehensive medical claims data and information from the National Health Screening Program. We compared the baseline characteristics of subjects with and without allergic diseases and calculated the incidence and risk of glaucoma development. Cox proportional hazard regression analysis was used to determine the risk of glaucoma development in subjects with allergic diseases. A total of 171,129 subjects aged 20-39 with or without allergic diseases who underwent a general health examination between 2009 and 2015 were included. Subjects with allergic diseases exhibited a higher incidence of glaucoma compared to the control group. The hazard ratio (HR) of glaucoma onset was 1.49 and 1.39 in subjects with at least one allergic disease before and after adjusting for potential confounding factors, respectively. Among allergic diseases, atopic dermatitis showed the highest risk for glaucoma development (aHR 1.73) after adjusting for confounders. Allergic rhinitis showed an increased risk for incident glaucoma after adjustment (aHR 1.38). Asthma showed the lowest but still increased risk for glaucoma (aHR 1.22). The associations were consistent in all subgroup analyses stratified by sex, smoking, drinking, exercise, diabetes, hypertension, dyslipidemia, or history of steroid. In conclusion, allergic diseases are associated with increased risk of glaucoma development. Among allergic diseases, atopic dermatitis showed the highest risk for glaucoma development followed by allergic rhinitis and asthma.

Gamma-glutamyl transferase and the risk of all-cause and disease-specific mortality in patients with diabetes: A nationwide cohort study

BACKGROUND

There exists a paucity of data regarding whether gamma-glutamyl transferase is associated with disease-specific mortality in patients with type 2 diabetes mellitus. This study aimed to investigate the association of serum gamma-glutamyl transferase levels with all-cause and disease-specific mortality in patients with diabetes mellitus using a Korean nationwide health-screening database.

METHODS

A total of 9 687 066 patients without viral hepatitis or liver cirrhosis who underwent health examination in 2009 were included. These patients were divided into four groups according to sex-specific quartiles of serum gamma-glutamyl transferase levels.

RESULTS

During a median follow-up period of 8.1 years, 222 242 deaths were identified. The all-cause mortality rate increased as the serum gamma-glutamyl transferase levels became higher (highest quartile vs lowest quartile: hazard ratio [HR], 1.57; 95% confidence interval [CI], 1.55-1.59; p for trend <.001). Similar trends were observed for cardiovascular disease (HR, 1.57; 95% CI, 1.53-1.62), ischemic heart disease (HR, 1.40; 95% CI, 1.33-1.48), and stroke (HR, 1.72; 95% CI, 1.60-1.85) in the highest quartile, as compared with the lowest quartile (p for trend <.001). As the gamma-glutamyl transferase quartiles became higher, mortality rates related to cancer (HR, 1.56; 95% CI, 1.52-1.60), liver disease (HR, 9.42; 95% CI, 8.81-10.07), respiratory disease (HR, 1.55; 95% CI, 1.49-1.62), and infectious disease (HR, 1.73; 95% CI, 1.59-1.87) also increased in the highest quartile, compared with the lowest quartile (p for trend <.001).

CONCLUSIONS

Serum gamma-glutamyl transferase levels may be useful for the risk assessment of all-cause and disease-specific mortality among patients with type 2 diabetes mellitus.

Weight changes after smoking cessation affect the risk of vertebral fractures: a nationwide population-based cohort study

BACKGROUND CONTEXT

Smoking cessation reduces the risk of vertebral and hip fractures but usually increases body weight. Since underweight is known as a risk factor for vertebral fractures, smoking cessation is considered to have a protective effect on vertebral fractures. However, the actual effect of weight change after smoking cessation on the risk of vertebral fractures remains uncertain.

PURPPOSE

This study aimed to assess the risk of vertebral fractures among individuals who reported smoking cessation with a specific focus on changes in body weight.

STUDY DESIGN

Retrospective cohort study based on nationwide health insurance database.

PATIENT SAMPLE

Participants were from nationwide biennial health checkups between 2007 and 2009 conducted by the Korean National Health Insurance Service. Participants were followed up from 2010 to 2018 to find incidence of newly developed vertebral fractures.

OUTCOME MEASURES

The incidence rate was defined as the incidence rate (IR) per 1,000 person-years (PY). Cox proportional regression analysis was used to analyze the risk of vertebral fracture to determine the hazard ratio (HR) associated with the incidence of vertebral fractures based on smoking status and weight changes.

METHODS

Based on their self-reported questionnaires, the participants were classified into three groups: current smokers, quitters, and nonsmokers. The quitter was defined as an individual who were smokers in 2007 and ceased smoking in 2009. Individuals with smoking cessation were categorized according to the weight change between baseline and 2 years prior: weight maintenance (-5∼5 % of weight change), weight loss (<-5 % of weight change), and weight gain (>5 % of weight change). We used Cox proportional hazards analysis to determine the hazard ratio (HR) associated with the incidence of vertebral fractures based on smoking status and temporal weight change over 2 years.

RESULTS

This study evaluated 913,805 eligible participants, of whom 672,858 were classified as nonsmokers, 34,143 as quitters, and 206,804 as current smokers. Among quitters, 2,372 (6.9%) individuals had weight loss, and 7,816 (22.9%) had weight gain over 2 years. About 23,952 (70.2%) individuals maintained their weight over 2 years. The overall risk of vertebral fractures was significantly higher in quitters (adjusted HR [aHR]=1.110, 95% confidence interval [CI] 1.013-1-216) than in nonsmokers, but it was lower than in current smokers (aHR=1.197, 95%CI 1.143-1.253), regardless of weight change after smoking cessation. However, individuals who experienced weight loss after smoking cessation exhibited a notably higher risk of vertebral fractures than current smokers (aHR=1.321, 95%CI 1.004-1.461). In the female population, weight gain after smoking cessation was associated with a higher risk of vertebral fractures (aHR = 1.470, 95%CI 1.002-2.587) than in current female smokers.

CONCLUSIONS

Maintaining weight after smoking cessation may mitigate the risk of vertebral fractures. Weight loss after smoking cessation adversely affects the protective effects of smoking cessation on vertebral fractures in the general population.

The risk of type 2 diabetes mellitus in multiple sclerosis and neuromyelitis optica spectrum disorder: A nationwide cohort study

BACKGROUND AND OBJECTIVES

An association has been suggested between premorbid type 2 diabetes mellitus (T2DM) and the risk of multiple sclerosis (MS). However, little is known about the risk of developing T2DM in MS and neuromyelitis optica spectrum disorder (NMOSD). This study aimed to determine the T2DM risk in patients with MS and NMSOD.

METHODS

The Korean National Health Insurance Service database was analyzed, and 1,801 and 1,721 adults with MS and NMOSD, respectively, who were free of T2DM between January 2010 and December 2017, were included. Matched controls were selected based on age, sex, and the presence of hypertension and dyslipidemia.

RESULTS

The risk of developing T2DM was 1.54 times higher in NMOSD than in the controls (adjusted hazard ratio [aHR], 95 % confidence interval [CI] = 1.20-1.96). However, increased T2DM risk was not observed in MS (aHR = 1.13, 95 % CI = 0.91-1.42). The T2DM risk in patients with NMOSD was higher in those who received steroid treatment (aHR = 1.77, 95 % CI = 1.36-2.30) but not in those who did not (aHR = 0.59, 95 % CI = 0.24-1.43, p for interaction = 0.02).

DISCUSSION

T2DM risk was increased in NMOSD but not in MS. Administering steroid treatment to patients with NMOSD may increase their T2DM risk.

Weight change in people with depression and the risk of dementia: a nationwide cohort study

BACKGROUND

Depression is a risk factor for dementia and weight change can appear as a symptom of depression. However, the association between weight change after the diagnosis of depression and the risk of dementia is poorly established. This study aimed to investigate the association between weight change before and after a diagnosis of depression with the subsequent risk of dementia.

METHODS

The National Health Insurance Sharing Service database was used. 1 308 730 patients aged ⩾40 years diagnosed with depression were identified to be eligible. Weight changes after their depression diagnosis were categorized and subsequent incidence of dementia was followed up.

RESULTS

During an average follow-up period of 5.2 years (s.d., 2.0 years), 69 373 subjects were newly diagnosed with all-cause dementia (56 351 were Alzheimer's disease and 6877 were vascular dementia). Regarding all outcomes, compared to those with a minimal weight change (-5 to 5%), all groups with weight gain or loss showed increased risks of dementia after adjusting potential risk factors for dementia, in all analysis models with a dose-response relationship, showing a U-shaped association.

CONCLUSIONS

Weight change as a symptom of depression could be a predictor for the future development of dementia.

The positive impact of smoking cessation on fracture risk in a nationwide cohort study

Many studies sought to demonstrate the association between smoking and fracture risk. However, the correlation between smoking and fractures remains controversial. This study aimed to examine the impact of smoking and smoking cessation on the occurrence of fractures using prospective nationwide cohort data. We enrolled those who underwent a National Health Insurance Service (NHIS) health checkup in 2009-2010 who had a previous health checkup 4-year prior (2005-2006). The study population of 4,028,559 subjects was classified into three groups (non-smoker, smoking cessation, current smoker). The study population was also analyzed according to fracture type (all fractures, vertebral fracture, hip fracture). Lastly, the smoking cessation group and current smoker group were divided into four subgroups based on a lifetime smoking amount cut-off of 20 pack-years (PY). Multivariate-adjusted hazard ratios (HRs) of fracture were examined through a Cox proportional hazards model. After multivariable adjustment, non-smokers showed the lowest risk of fracture (HR = 0.818, CI 0.807-0.828, p < 0.0001) and smoking cessation significantly lowered the risk of fracture (HR 0.938, 95% CI 0.917-0.959, p < 0.0001) compared to current smokers. Regardless of 20PY, all smoking cessation subgroups showed significantly less risk of fractures than current smokers with ≥ 20PYs. Smoking increases the risk of fracture, and smoking cessation lowers the risk of fracture.

Fracture Risk Among Stroke Survivors According to Poststroke Disability Status and Stroke Type

BACKGROUND

Stroke survivors face physical and cognitive challenges, leading to an increased dependency and a higher fall risk. We aimed to investigate the impact of poststroke disability and stroke type on fracture risk at various sites compared with matched controls.

METHODS

This retrospective cohort study used data from the Korean National Health Insurance System database (2010-2018), including patients with stroke and 1:1 matched controls. Stroke survivors were grouped based on the presence and severity of their poststroke disability and stroke type. The primary outcome was a newly diagnosed fracture, analyzed by Cox proportional hazard regression analyses adjusting for potential confounders.

RESULTS

Among 223 358 stroke survivors (mean age, 64.8±10.9 years; 61.2% men), 16 344 fractures occurred during a mean follow-up of 3.7±2.5 years. In matched controls (n=322 161; mean age, 65.4±11.2 years; 61.3% men), 20 398 fractures were identified. Stroke survivors had increased overall fracture risk compared with matched controls (adjusted hazard ratio [aHR], 1.40 [95% CI, 1.37-1.43]). Specifically, hip fracture risk was even greater in stroke survivors (incidence rate per 1000 person-years, 4.7 [95% CI, 4.5-4.8]; aHR, 2.42 [95% CI, 2.30-2.55]) than controls (incidence rate, 2.2 [95% CI, 2.1-2.3]). The risk of vertebral fractures (aHR, 1.29 [95% CI, 1.25-1.34]) and other fractures (aHR, 1.19 [95% CI, 1.15-1.23]) was also higher than that of the control group. Hip fracture risk was the highest among stroke survivors with severe poststroke disability (aHR, 4.82 [95% CI, 4.28-5.42]), although vertebral or other fracture risk was the highest among those with mild poststroke disability. No significant difference in fracture risk was found between hemorrhagic and ischemic stroke survivors when stratified by disability status.

CONCLUSIONS

Our findings showed increased subsequent fracture risk among stroke survivors, particularly those with poststroke disability and for hip fracture. Bone health assessment and treatment should be emphasized as an essential part of stroke management.

Association between glycemic status and the risk of gastric cancer in pre/peri-and postmenopausal women: A nationwide cohort study

PURPOSE

This study aimed to assess the correlation between glycemic status (prediabetes and type 2 diabetes mellitus) and the risk of gastric cancer according to menopausal status.

METHODS

A total of 982,559 pre/peri-menopausal and 1445,419 postmenopausal women aged ≥ 40, who underwent the Korean national health screening in 2009, were included and followed up until 2018. Hazard ratio (HR) and 95% confidence interval (CI) were calculated for development of gastric cancers according to hyperglycemic status in both groups using Cox proportional hazards models.

RESULTS

Over a mean follow-up period of 8.3 years, 3259 (0.33%) pre/peri-menopausal women and 13,245 (0.92%) postmenopausal women were diagnosed with gastric cancer. In postmenopausal women, only diabetes mellitus conferred a higher risk of gastric cancer compared to normal glycemic status (HR, 1.15; 95% CI, 1.09-1.20), with an increasing trend of gastric cancers from prediabetes to diabetes (P for trend < 0.001) observed regardless of menopausal status. Obesity, smoking, and heavy alcohol consumption was associated with increased gastric cancer risk mainly in the postmenopausal period.

CONCLUSIONS

The risk of gastric cancer escalates with deteriorating glycemic status in a dose-response manner. Diabetes mellitus is linked with an elevated risk of gastric cancer in postmenopausal women.

Changes in physical activity and diabetes risk after cancer diagnosis: a nationwide cohort study

PURPOSE

Physical activity has the potential to reduce the risk of diabetes after cancer diagnosis. However, current evidence supporting its effects is limited. This study aims to examine the associations between changes in physical activity and subsequent risk of diabetes among cancer survivors.

METHODS

A total of 264,250 cancer survivors (mean age 56.7 (12.5) years, 44.2% males) without a prior history of diabetes were assessed for adherence to physical activity both before and after their diagnosis. The primary outcome was incident diabetes. The Fine-Gray proportional sub-distribution hazards model was used to calculate sub-distribution hazard ratios (sHRs) and 95% confidence intervals (CIs) for diabetes risk, considering death as a competing risk.

RESULTS

Over a follow-up of 1,065,802 person-years, maintaining regular physical activity from pre-diagnosis was associated with a 10% reduced risk of diabetes after cancer diagnosis (sHR 0.90, 95% CI 0.85-0.96), considering traditional diabetes risk factors, sociodemographics, and primary cancer sites. Cancer survivors who became active and inactive after their cancer diagnosis exhibited a marginally decreased risk of diabetes (sHR 0.98, 95% CI 0.93-1.03; sHR 0.97, 95% CI 0.92-1.03). The strength and direction of the association varied depending on the primary site of cancer.

CONCLUSIONS

Regular physical activity starting before a cancer diagnosis is associated with a lower risk of diabetes following the diagnosis, independent of established diabetes risk factors.

IMPLICATIONS FOR CANCER SURVIVORS

The study underscores the importance of engaging in sufficient physical activity to mitigate the risk of diabetes in cancer survivors.

Cardiorenal outcomes and mortality after sodium-glucose cotransporter-2 inhibitor initiation in type 2 diabetes patients with percutaneous coronary intervention history

AIMS

To evaluate the effects of initiating sodium-glucose cotransporter-2 (SGLT2) inhibitors on cardiorenal outcomes and mortality compared to dipeptidyl peptidase-4 (DPP-4) inhibitors as active comparators in patients diagnosed with type 2 diabetes with a history of percutaneous coronary intervention (PCI).

MATERIALS AND METHODS

We used an active-comparator, new-user design and nationwide data from the National Health Insurance Service in South Korea from 2014 to 2019. Of the 56 392 patients who underwent PCI, 4610 new SGLT2 inhibitor users were paired 1:1 with DPP-4 inhibitor users for analysis using propensity-score matching.

RESULTS

During 13 708.59 person-years of follow-up, the initiation of SGLT2 inhibitors, compared with the initiation of DPP-4 inhibitors, was associated with a significantly lower risk of composite repeat revascularization, myocardial infarction, stroke, heart failure (HF), all-cause death and end-stage renal disease (ESRD). The beneficial effects of SGLT2 inhibitor use were consistent with the components of stroke, HF, all-cause death and ESRD. In the cohort that included health examination data, including anthropometric and metabolic factors, new use of SGLT2 inhibitors was associated with a significantly lower risk of HF (hazard ratio [HR] 0.574, 95% confidence interval [CI] 0.36-0.915), all-cause death (HR 0.731, 95% CI 0.567-0.942), and ESRD (HR 0.076, 95% CI 0.018-0.319). The effects of SGLT2 inhibitor use were consistent regardless of the timing of the previous PCI.

CONCLUSIONS

The initiation of SGLT2 inhibitors in patients with type 2 diabetes and a history of PCI was significantly associated with a reduced risk of cardiorenal consequences and mortality, irrespective of time since the last PCI.

Association between migraine and the risk of vascular dementia: A nationwide longitudinal study in South Korea

OBJECTIVE

We aimed to examine the potential association between migraine and vascular dementia (VaD) using a nationwide population database.

BACKGROUND

Migraine and VaD showed similar structural and functional changes in pathophysiology process and shared common risk factors, However, whether migraine prevalence increases VaD incidence remains controversial.

METHODS

This retrospective population-based cohort study used the medical records from the Korean National Health Insurance System database. Migraine (G43) was defined by using the Tenth Revision of the International Classification of Diseases code. More than two migraine diagnoses at least 3 months apart were defined as "chronic migraine". Cox proportional hazards model estimated hazard ratios (HRs) of VaD for group comparisons.

RESULTS

We included 212,836 patients with migraine and 5,863,348 individuals without migraine. During 10 years of follow-up, 3,914 (1.8%) and 60,258 (1.0%) patients with and without migraine, respectively, were newly diagnosed with VaD. After adjustment, patients with migraine showed a 1.21-fold higher risk of VaD than those without migraine (HR = 1.21; 95% confidence interval (CI): 1.17-1.25). Patients with chronic migraine showed a higher cumulative incidence of VaD than those with episodic migraine. The adjusted HR for the VaD incidence with migraine was higher in: (1) patients aged <65 years; (2) women; (3) patients without hypertension, diabetes, or atrial fibrillation; and (4) non-smokers.

CONCLUSION

Migraine is associated with an increased risk of VaD, particularly in chronic migraine patients. Incidence of VaD in the setting of migraine may have distinct pathophysiology from that of VaD with traditional cardiovascular risks.

Diabetes severity and the risk of depression: A nationwide population-based study

BACKGROUND

In consideration of the substantial occurrence rates of diabetes mellitus (DM) and depression, it is imperative to identify patients with DM who are at an elevated risk of developing depression. Accordingly, this study aimed to examine whether the risk of depression escalated proportionally with the severity of diabetes.

METHODS

2,067,017 adults diagnosed with type 2 DM, with the exception of those diagnosed with depression either before or within one year of the index date, were identified from a nationwide population-based cohort in Korea. Severity scores for DM were established based on various factors, including insulin use, DM duration of at least 5 years, use of three or more oral hypoglycemic agents, the presence of chronic kidney disease (CKD), cardiovascular diseases (CVD), or diabetic retinopathy. Each of these attributes was assigned a score of one point for diabetes severity, and their cumulative sum was defined as a diabetes severity score, ranging from 0 to 6.

RESULTS

During a median follow-up of 6.2 years, 407,047 cases of major depression were identified. Each component contributing to the DM severity score was significantly associated with an increased risk of depression (all P-values <0.001), with insulin use and the presence of CVD demonstrating the most significant correlation with depression risk. As the DM severity score increased, the risk of depression was observed to significantly escalate (P for trend <0.001). After adjusting for potential confounding variables, the hazard ratios (95% confidence intervals) of depression were 1.15 (1.14-1.16) in 1 point, 1.28 (1.27-1.29) in 2 points, 1.45 (1.43-1.47) in 3 points, 1.70 (1.67-1.73) in 4 points, 1.91 (1.84-1.98) in 5 points, and 2.01 (1.79-2.26) in 6 points, respectively.

CONCLUSION

The results of this study indicate that diabetes severity is positively associated with an elevated risk of developing major depression. Based on these findings, it is feasible to consider targeting depression screening efforts towards individuals with higher diabetes severity scores.

Metabolic dysfunction-associated steatotic liver disease and risk of esophageal cancer in patients with diabetes mellitus: a nationwide cohort study

Metabolic dysfunction-associated steatotic liver disease (MASLD) is closely associated with type 2 diabetes and a developing several cancers including esophageal cancer (EC). However, the association between MASLD and EC in diabetic patients has not been investigated. Therefore, we aimed to investigate the relation between MASLD and developing EC in diabetic patients. This was a population-based retrospective cohort study of data from the Korean National Health Insurance Service (NHIS). A total of 1,904,468 subjects diagnosed with diabetes who underwent NHIS-provided health checkups from 2009 to 2012 were included. We constructed a Cox proportional hazard model for the association of fatty liver index (FLI) and the risk of EC stratified by potential confounders. Over a mean follow-up duration of 6.9 years, the incidence of EC was higher in the high (≥60) FLI group compared to the low (<30) FLI group (14.4 vs. 13.7 event per 100,000 person-years). The risk of EC correlated with the degree of FLI, particularly in older (P = 0.002), female (P = 0.033), non-smoking (P = 0.002), and non-drinking patients (P = 0.025). Among obese patients, the risk of EC was not associated with FLI; however, the risk of EC was higher in the high FLI group in non-obese patients. Lean MASLD patients had the highest risk of EC (adjusted hazard ratio 1.78; 95% confidence interval, 1.5-2.13). MASLD was associated with an increased risk of EC in diabetic patients, and lean MASLD has the highest risk. Further studies are required to determine the causal relationship between MASLD and EC.

Association between dental scaling and metabolic syndrome and lifestyle

PURPOSE

Periodontal disease is a risk factor for diabetes and metabolic syndrome, and non-surgical periodontal treatment has been shown to help maintain stable blood sugar in diabetic patients. Determining the level of preventive scaling in patients with metabolic syndrome will help manage the disease. The purpose of this study was to investigate the extent to which people with metabolic syndrome or bad lifestyle performed scaling and the association between preventive scaling and metabolic syndrome or lifestyle in a large population.

METHODS

This study was conducted on adults aged 20 years or older from January 2014 to December 2017 in the National Health Insurance System (NHIS) database. Among 558,067 people who underwent health checkups, 555,929 people were included. A total of 543,791 people were investigated for preventive scaling. Metabolic syndrome components were abdominal obesity, lower high density lipoprotein cholesterol (HDL)-C, high triglycerides, high blood pressure and hyperglycemia. Unhealthy lifestyle score was calculated by assigning 1 point each for current smokers, drinkers, and no performing regular exercise.

RESULTS

When multiple logistic regression analysis was performed after adjusting for age, sex, income, body mass index (BMI), smoking, drinking and regular exercise, the Odds ratios (OR) and 95% confidence intervals (CI) of the group with 5 metabolic syndrome components were 0.741 (0.710, 0.773) (p<0.0001). After adjustment for age, sex, income, BMI, smoking, drinking, regular exercise, diabetes, hypertension and dyslipidemia, the OR (95% CI) of the group with unhealthy lifestyle score = 3 was 0.612 (0.586, 0.640) (p<0.0001).

CONCLUSIONS

The more metabolic syndrome components, and the higher unhealthy lifestyle score, the less scaling was performed.

Association between statin use and the risk for idiopathic pulmonary fibrosis and its prognosis: a nationwide, population-based study

Given the pleiotropic effects of statins beyond their lipid-lowering effects, there have been attempts to evaluate the role of statin therapy in IPF, but they have shown inconclusive results. Data from the National Health Insurance Service (NHIS) database of South Korea were used to investigate the effects of statin therapy on IPF. The IPF cohort consisted of a total of 10,568 patients who were newly diagnosed with IPF between 2010 and 2017. These patients were then matched in a 1:3 ratio to 31,704 subjects from a control cohort without IPF, with matching based on age and sex. A case-control study was performed to evaluate the association between statin use and the risk for IPF, and the multivariable analysis revealed that statin use was associated with a lower risk for IPF (adjusted OR 0.847, 95% CI 0.800-0.898). Using the IPF cohort, we also evaluated whether statin use at the time of diagnosis was associated with future clinical outcomes. The statin use at the time of IPF diagnosis was associated with improved overall survival (adjusted HR 0.779, 95% CI 0.709-0.856). Further prospective studies are needed to clarify the role of statin therapy in IPF.

Changes in Fatty Liver Disease and Incident Diabetes Mellitus in Young Korean Adults

INTRODUCTION

This study sought to assess the association between the changes in nonalcoholic fatty liver disease (NAFLD) and risk of type 2 diabetes in young individuals with prediabetes.

METHODS

Data from the Korean National Health Insurance System database were collected from 2009 to 2019 and analyzed in 2022. A total of 446,813 young adults aged 20-39 years with prediabetes who underwent two National Health Screening examinations from 2009 to 2012 were followed up. NAFLD was defined as a fatty liver index≥60 without liver disease or history of alcohol abuse. Multivariable Cox proportional hazards regression was used to calculate the HR and CIs for type 2 diabetes according to NAFLD changes.

RESULTS

During a median follow-up of 8.3 years, 26,464 (5.9%) young individuals developed type 2 diabetes. Multivariable adjusted HR of type 2 diabetes according to the NAFLD change was 5.38 (95% CI 5.08-5.70) in individuals with persistent NAFLD when compared to those who never had NAFLD. Even in individuals who were consistently nonobese, resolved NAFLD, new NAFLD, and persistent NAFLD were associated with>3-fold increased risk of type 2 diabetes compared to nonobese individuals without NAFLD. The risk of type 2 diabetes also increased in obese individuals without NAFLD by 2-fold when compared to nonobese individuals without NAFLD.

CONCLUSIONS

NAFLD that either existed persistently or ever existed plays a critical role in the development of type 2 diabetes in young adults with or without obesity. Nonobese individuals with NAFLD warrant special attention.

Risk of Parkinson disease in stroke patients: A nationwide cohort study in South Korea

BACKGROUND AND PURPOSE

Previous studies have examined the risk of stroke in patients with Parkinson disease (PD), but the incidence of PD onset among stroke patients and its risk according to severity of poststroke disabilities have scarcely been investigated. This study aims to determine whether the risk of PD is increased among stroke patients using a retrospective cohort with a large population-based database.

METHODS

We used data collected by the Korean National Health Insurance Service from 2010 to 2018 and examined 307,361 stroke patients and 380,917 sex- and age-matched individuals without stroke to uncover the incidence of PD. Cox proportional hazards regression was used to calculate the hazard ratio (HR) and 95% confidence interval (CI), and the risk of PD was compared according to presence and severity of disability.

RESULTS

During 4.31 years of follow-up, stroke patients had a 1.67 times higher risk of PD compared to individuals without stroke (adjusted HR = 1.67, 95% CI = 1.57-1.78). The risk of PD was greater among stroke patients with disabilities than among those without disabilities, even after adjustment for multiple covariates (adjusted HR = 1.72, 95% CI = 1.55-1.91; and adjusted HR = 1.66, 95% CI = 1.56-1.77, respectively).

CONCLUSIONS

Our study demonstrated an increased risk of PD among stroke patients. Health professionals need to pay careful attention to detecting movement disorders as clues for diagnosing PD.

Association between dental diseases and oral hygiene care and the risk of vertebral fracture: a nationwide cohort study

Periodontal disease and increased missing teeth were associated with incident vertebral fractures. In contrast, professional dental cleaning and frequent tooth brushing, was associated with a lower risk of vertebral fracture. Better oral hygiene care attenuated the risk associated with dental diseases.

PURPOSE

To investigate the association between oral health and the risk of vertebral fractures.

METHODS

We included 2,532,253 individuals aged ≥40 years who underwent the Korean National Health Insurance Service health examinations in 2008 and followed up until December 31, 2017. We performed multivariable Cox proportional hazard regression analyses to evaluate the association between dental diseases and oral hygiene care and the risk of vertebral fractures.

RESULTS

Over the 9.3-year median follow-up, 1.46% (n = 36,857) experienced vertebral fractures. Individuals with dental diseases had a higher risk of vertebral fracture than those without (hazard ratio [HR] 1.04, 95% confidence interval [CI]: 1.02-1.07 for periodontal diseases; 1.02, 1.00-1.05 for dental caries; 1.12, 1.05-1.20 for ≥15 missing teeth). Good oral hygiene care was associated with a lower vertebral fracture risk (HR 0.89, 95% CI: 0.86-0.91 for ≥1 time/year [vs. <1 time/year] of professional dental cleaning; 0.90, 0.87-0.93 for ≥2 times/day [vs. 0-1 time/day] of toothbrushing). The combined dental diseases was significantly associated with an increased vertebral fracture risk, whereas combined oral hygiene care was associated with further risk reduction. Better oral hygiene care reduced vertebral fracture risk associated with dental diseases (all P <0.001).

CONCLUSION

Periodontal disease, dental caries, and an increased number of missing teeth were independently associated with higher risks for vertebral fractures. Conversely, improved oral hygiene care, such as personal dental cleaning and frequent tooth brushing, may modify vertebral fracture risks associated with dental disease.

Ocular Involvement and Treatment Pattern in Korean Patients with Marfan Syndrome: A Population-Based Study

PURPOSE

This study aimed to investigate the incidence and prevalence of, and treatment patterns for ocular complications in Korean patients with Marfan syndrome.

METHODS

Incidence and prevalence of Marfan syndrome was calculated from 2010 to 2018, based on data from the Korean National Health Insurance Service (KNHIS). Diagnosis codes (for cataract, ectopia lentis, retinal detachment, etc.) and surgery reimbursement codes (lensectomy, phacoemulsification, buckling, vitrectomy, etc.) in the patients with Marfan syndrome were retrieved by complete enumeration of the data.

RESULTS

The annual prevalence of Marfan syndrome adjusted by age and sex was gradually increased from 2.44 per 100,000 in 2010 to 4.36 per 100,000 in 2018. The age group of 10-19 years showed the highest prevalence. The prevalence of ectopia lentis was 21.7%, of whom 43.0% underwent surgeries. Surgery for RD was performed in 253 (14.1%) of 2044 patients during the study period.

CONCLUSION

Although the most prevalent ophthalmologic manifestation was ectopia lentis, total prevalence rate of RD was more than 10% in the study period; thus, regular fundus examination is recommended for the patients with Marfan syndrome.

J-shaped association between LDL cholesterol and cardiovascular events: A longitudinal primary prevention cohort of over 2.4 million people nationwide

INTRODUCTION

Low-density lipoprotein (LDL) cholesterol-lowering treatment is beneficial for the secondary or primary prevention of high-risk atherosclerotic cardiovascular disease (ASCVD). However, the prognostic implications of low LDL cholesterol levels in patients without previous ASCVD and without statin use remain elusive.

METHODS

From a nationwide cohort, 2,432,471 participants without previous ASCVD or statin use were included. For myocardial infarction (MI) and ischemic stroke (IS), participants were followed-up from 2009 to 2018. They were stratified according to 10-year ASCVD risk (<5 %, 5 %-<7.5 %, 7.5 %-<20 %, and ≥20 %) and LDL cholesterol level (<70, 70-99, 100-129, 130-159, 160-189, and ≥190 mg/dL).

RESULTS

The relationship between LDL cholesterol levels and ASCVD events exhibited a J-shaped curve for both MI and IS. After classification according to the ASCVD risk, this J-shaped relationship was consistently observed for the composite of MI and IS. Participants with an LDL cholesterol level <70 mg/dL showed a higher MI risk than those with a level of 70-99 mg/dL or 100-129 mg/dL in the low-ASCVD risk group. The J-shaped curve between LDL cholesterol levels and MI risk was attenuated across ASCVD risk groups. For IS, participants with an LDL cholesterol level <70 mg/dL demonstrated increased risks compared with those with a level of 70-99 mg/dL, 100-129 mg/dL, or 130-159 mg/dL in the borderline, intermediate, and high ASCVD risk groups, respectively. In contrast, a linear association was observed in participants taking statins. Interestingly, a J-shaped association was observed between LDL cholesterol and high-sensitivity C-reactive protein (hs-CRP) levels; the mean hs-CRP level and the proportion of individuals with increased hs-CRP levels were relatively high among individuals with an LDL cholesterol level <70 mg/dL.

CONCLUSIONS

Although high LDL cholesterol levels increase the risk of ASCVD, low LDL cholesterol levels do not warrant safety from ASCVD. Therefore, individuals with low LDL cholesterol levels should be carefully monitored.

Impact of Smoking and Alcohol Consumption on Early-Onset Gastric Cancer Development in Young Koreans: A Population-Based Study

PURPOSE

Although smoking and alcohol consumption are known risk factors for gastric cancer (GC), studies assessing their effects on early-onset GC are limited. In this nationwide, population-based, prospective cohort study, we assessed the effects of smoking and alcohol consumption on early-onset GC in patients aged <50 years.

MATERIALS AND METHODS

We analyzed data of patients aged 20-39 years who underwent cancer and general health screening in the Korean National Health Screening Program between 2009 and 2012. We calculated the adjusted hazard ratios (aHR) and 95% confidence intervals (CI) for GC incidence until December 2020.

RESULTS

We enrolled 6,793,699 individuals (men:women=4,077,292:2,716,407) in this cohort. The mean duration of follow-up was 9.4 years. During follow-up, 9,893 cases of GC (men:women=6,304:3,589) were reported. Compared with the aHRs (95% CI) of never-smokers, those of former and current-smokers were 1.121 (1.044-1.205) and 1.282 (1.212-1.355), respectively. Compared with the aHRs (95% CI) of non-consumers, those of low-moderate- and high-risk alcohol consumers were 1.095 (1.046-1.146) and 1.212 (1.113-1.321), respectively. GC risk was the highest in current-smokers and high-risk alcohol consumers (1.447 [1.297-1.615]). Interestingly, alcohol consumption and smoking additively increased the GC risk in men but not in women (Pinteraction=0.002).

CONCLUSION

Smoking and alcohol consumption are significant risk factors for early-onset GC in young Koreans. Further studies are needed to investigate sex-based impact of alcohol consumption and smoking on GC incidence in young individuals.

Trends in underweight and severe underweight disparities in Korean adults and older adults: a nationwide, repeated cross-sectional study

OBJECTIVES

Little is known about the disparities in underweight prevalence among the general population in high-income countries. We investigated the trends in underweight prevalence and disparities across sociodemographic groups among Korean adults and older adults.

SETTING AND PARTICIPANTS

A series of cross-sectional data on Korean national health checkups for adults aged ≥20 years were analyzed from 2005 to 2016.

MEASUREMENTS

Based on body mass index (kg/m2), underweight was graded as mild (17.0-18.49), moderate (16.0-16.9), and severe (<16.0). Underweight prevalence was compared across sociodemographic subgroups in 2015-2016. Trends in underweight disparities were examined from 2005-2006 to 2015-2016. Multivariable-adjusted odds ratios (ORs; 95% confidence intervals, CIs) were calculated using logistic regression.

RESULTS

Approximately 11-22 million adults were included in each wave. In 2015-2016, the overall prevalence of underweight was 3.6% (men 2.0%, women 5.2%); severe underweight was 0.2% (men 0.1%, women 0.3%). The prevalence of underweight varied by sex and age groups. In men, those aged ≥80 years had the highest prevalence (overall 7.33%, severe underweight 0.84%). In women, those aged 20-29 years had the highest prevalence of overall underweight (14.57%), whereas those aged ≥80 years had the highest prevalence of severe underweight (1.38%). Compared with individuals in the lowest income quartile, men in the highest income had lower ORs of overall (0.59, 95% CI 0.59-0.60) and severe underweight (0.46, 95% CI 0.44-0.48); women in the highest income quartile had a higher OR of overall (1.12, 95% CI 1.12-1.13) but a lower OR of severe underweight (0.89, 95% CI 0.86-0.92). From 2005-2006 to 2015-2016, severe underweight consistently declined in older men but remained constant in women aged ≥80 years, widening sex disparities among older adults. Severe underweight decreased or leveled off in the highest income quartile but steadily increased in the lowest quartile, worsening income disparities.

CONCLUSION

In this nationwide study, underweight was more prevalent among women, older adults aged ≥80 years, and low-income individuals. Disparities in severe underweight widened across sociodemographic subgroups over time.

Association of physical activity with fractures in kidney transplant recipients: A Korean nationwide cohort study

Kidney transplant recipients are at high risk for fractures, primarily due to post-transplant bone disease. This retrospective cohort study analyzed data from the Korean National Health Insurance Service, including 10 083 kidney transplant recipients examined from 2009 to 2017. We assessed fracture incidence, emphasizing vertebral and hip fractures, and the association of physical activity and traditional risk factors with fracture risk. Kidney transplant recipients were categorized into three groups according to physical activity levels: non-activity, metabolic equivalent of task (MET) 1-499, and MET ≥500. Physical activity was associated with a decreased risk of all types of fractures: any (MET 1-499: adjusted hazard ratio (aHR) .75; 95% confidence interval (CI) .62-.92, MET ≥500: aHR .84; 95% CI .70-1.00), vertebral (MET 1-499: aHR .69; 95% CI .49-.98, MET ≥500: aHR .67; 95% CI .49-.91), and hip (MET 1-499: aHR .43; 95% CI .23-.81) fractures. Additionally, older age, female sex, and diabetes were associated with an increased fracture risk. The assessment of physical activity and traditional risk factors could improve fracture risk prediction. Our findings emphasize the need for further research to establish optimal physical activity recommendations for fracture prevention in kidney transplant recipients.

2023 Obesity Fact Sheet: Prevalence of Obesity and Abdominal Obesity in Adults, Adolescents, and Children in Korea from 2012 to 2021

Background

The 2023 Obesity Fact Sheet aims to present an updated overview of obesity prevalence across all age groups, including children and adolescents.

Methods

This study included individuals aged ≥20 years (n=16,941,423 in 2021) who underwent health checkups provided by the Korean National Health Insurance Service between 2012 and 2021. The prevalence of obesity and abdominal obesity was standardized by age and sex using data from the 2010 population and housing census. For children and adolescents (6 to 18 years) (n=884 in 2021), we used the Korea National Health and Nutrition Examination Survey (2012 to 2021), and obesity was defined by the corresponding sex- and age-specific body mass index percentile of 95th or greater based on the 2017 Korean National Growth Chart for Children and Adolescents.

Results

The overall prevalence of obesity in 2021 is 38.4% (49.2% in men and 27.8% in women), which is a 1.27-fold increase from 30.2% in 2012. The prevalence of obesity has increased across all age groups, particularly among those aged 20, 30, and 80 years. The prevalence of class III obesity substantially increased from 0.35% (men) and 0.42% (women) in 2012 to 1.21% and 0.97% in 2021, with 3.46- and 2.31-fold increases, respectively. This increase was particularly pronounced in young adults. The prevalence of obesity in children and adolescents has surged from 9.7% in 2012 to 19.3% in 2021, with a greater increase among boys.

Conclusion

Our study provides information on the current status of obesity prevalence based on the 2023 Obesity Fact Sheet, emphasizing the urgency of implementing timely strategies to reverse this increasing trend.

Increased Risk of Incident Chronic Obstructive Pulmonary Disease and Related Hospitalizations in Tuberculosis Survivors: A Population-Based Matched Cohort Study

BACKGROUND

Tuberculosis (TB) survivors have an increased risk of developing chronic obstructive pulmonary disease (COPD). This study assessed the risk of COPD development and COPD-related hospitalization in TB survivors compared to controls.

METHODS

We conducted a population-based cohort study of TB survivors and 1:1 age- and sex-matched controls using data from the Korean National Health Insurance Service database collected from 2010 to 2017. We compared the risk of COPD development and COPD-related hospitalization between TB survivors and controls.

RESULTS

Of the subjects, 9.6% developed COPD, and 2.8% experienced COPD-related hospitalization. TB survivors had significantly higher COPD incidence rates (36.7/1,000 vs. 18.8/1,000 person-years, P < 0.001) and COPD-related hospitalization (10.7/1,000 vs. 4.3/1,000 person-years, P < 0.001) than controls. Multivariable Cox regression analyses revealed higher risks of COPD development (adjusted hazard ratio [aHR], 1.63; 95% confidence interval [CI], 1.54-1.73) and COPD-related hospitalization (aHR, 2.03; 95% CI, 1.81-2.27) in TB survivors. Among those who developed COPD, the hospitalization rate was higher in individuals with post-TB COPD compared to those with non-TB COPD (10.7/1,000 vs. 4.9/1,000 person-years, P < 0.001), showing an increased risk of COPD-related hospitalization (aHR, 1.84; 95% CI, 1.17-2.92).

CONCLUSION

TB survivors had higher risks of incident COPD and COPD-related hospitalization compared to controls. These results suggest that previous TB is an important COPD etiology associated with COPD-related hospitalization.

Prevalence and Risk Factors of Age-Related Macular Degeneration in South Korea: Korea National Health and Nutrition Examination Survey

PURPOSE

To evaluate the prevalence and risk factors of age-related macular degeneration (AMD) in the Korean population.

METHODS

In this cross-sectional study based on the Korea National Health and Nutrition Examination Survey (2017-2020) data 13,737 participants aged ≥ 40 years with assessable fundus images were included. The prevalence and risk factors of AMD were evaluated. The prevalence of early AMD, geographic atrophy (GA), and neovascular AMD were also assessed. Logistic regression analyses were used to identify risk factors.

RESULTS

The prevalence (95% confidence interval [CI]) of AMD was 13.94% (13.15-14.72). The prevalence (95% CI) of early AMD, GA, and neovascular AMD was 13.07% (12.29-13.85), 0.26% (0.17-0.35), and 0.61% (0.47-0.75), respectively. The prevalence increased with age; it was 3.61%, 11.33%, 20.31%, 31.37%, and 33.98% in participants in their 40s, 50s, 60s, 70s, and ≥ 80 years, respectively. In multivariate analysis, AMD was positively associated with older age (p < 0.001; odds ratio [OR], 1.08; 95% CI, 1.07-1.09), male sex (p = 0.014; OR, 1.27; 95% CI, 1.05-1.53), and lower degree of education (p < 0.001; OR, 1.36 (for junior high school graduates); 95% CI, 1.12-1.65).

CONCLUSIONS

AMD was detected in approximately one-third of individuals aged ≥ 70 years, thus indicating that AMD is a common disease among older Koreans. Regular fundus examinations in populations with risk factors for AMD as well as education on methods to prevent or delay AMD progression, such as the Mediterranean diet, are necessary.

Current status of contact lenses usage in Korea: A population-based cohort study 2021

PURPOSE

To investigate trends in contact lens usage in a nationally representative sample of the Korean population in 2021.

METHODS

For this retrospective study, we analyzed data of 3,601 Korean participants aged 10-59 years, from the Korea National Health and Nutrition Examination Survey (KNHANES 2021 version), who underwent eye examination, of whom 1,136 individuals (274 men and 862 women) were contact lens users. The demographic trend among Korean contact lens wearers was examined using statistical analyses to investigate the changes in their contact lens-wearing experience, duration of lens use, type of lens used, location of purchase, presence of an Eye Care Practitioner(ECP)'s prescription, lens-related ophthalmic complications, and type of lenses worn at the time of complications, according to sex. Multivariable logistic regression analysis was conducted to examine the association of each variable with the rate of complications and use of soft lenses.

RESULTS

The average age of the contact lens users was 33.42±0.33 years, with 70.36% (weighted percentage) of users being women who used contact lenses for significantly longer periods than men (p<0.001). Additionally, only wearing of cosmetic lenses was significantly correlated with the occurrence of complications (p = 0.006), and 6.76% of users purchased lenses without a prescription. Multivariate analysis among the contact lens users revealed a significant relationship between the complication rate and female sex (p = 0.002), pre-existing eye disease diagnosed by ECPs (p = 0.0288), and duration of contact lens use (p<0.0001).

CONCLUSION

We identified sex differences in contact lens usage trends in Korea. The main changes observed were an increase in middle-aged lens users and a decrease in female users compared to that in the early 2000s. In addition, contact lens complications were significantly associated with sex and pre-existing eye disease. Therefore, those wearing contact lenses for extended periods should exercise caution and consult eye care specialists in the presence of any symptoms.

Associations between body weight change and incidence of major depressive disorder in patients with type 2 diabetes mellitus: a nationwide longitudinal follow-up cohort study of 1.1 million

BACKGROUND

Comorbid depression substantially affects the management of glycemia and diabetes-related complications among patients with type 2 diabetes mellitus. In this study, we sought to determine the association between weight change over 4 years and depression risk among patients with type 2 diabetes mellitus.

METHODS

This population-based retrospective cohort study from the National Health Insurance Services of Korea included 1 111 345 patients with type 2 diabetes who were divided into groups according to body weight change over 4 years. Body weight changes were compared with the preceding 4-year period (2005-2008). Depression was defined according to the International Classification of Diseases 10th revision code for depression (F32 and F33) on one or more inpatient or outpatient claims.

RESULTS

During a median follow-up of 7.4 years, 244 081 cases of depression were identified. We observed a U-shaped association between body weight change and depression risk with a higher risk among both groups of weight loss (hazard ratio (HR) 1.17, 95% CI 1.15-1.19 for ⩾ -10%; HR 1.07, 95% CI 1.06-1.08 for -10 to -5%) and weight gain (HR 1.06, 95% CI 1.04-1.08 for ⩾10%; HR 1.02, 95% CI 1.01-1.04 for 5-10%) compared with the stable weight group (-5 to 5%).

CONCLUSIONS

A U-shaped association between body weight change and depression risk was observed in this large nationwide cohort study. Our study suggests that patients with type 2 diabetes and weight change, either gain or loss, could be considered a high-risk group for depression.

Rheumatoid Arthritis and Risk of Depression in South Korea

Importance

Depression is among the most common comorbidities in rheumatoid arthritis (RA). There is a lack of data regarding the association of RA seropositivity and biologic agents with depression risk among individuals with RA.

Objective

To investigate the risk of depression following RA diagnosis among patients in South Korea.

Design, Setting, and Participants

This retrospective cohort study included 38 487 patients with RA and a comparison group of 192 435 individuals matched 1:5 for age, sex, and index date. Data were from the Korean National Health Insurance Service database. Participants were enrolled from 2010 to 2017 and were followed up until 2019. Participants who had previously been diagnosed with depression or were diagnosed with depression within 1 year after the index date were excluded. Statistical analysis was performed in May 2023.

Exposures

Seropositive RA (SPRA) was defined with the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes M05 and enrollment in the Korean Rare and Intractable Diseases program. Seronegative RA (SNRA) was defined with ICD-10 codes M06 (excluding M06.1 and M06.4) and a prescription of any disease-modifying antirheumatic drugs (DMARDs) for 270 days or more.

Main Outcomes and Measures

Newly diagnosed depression (ICD-10 codes F32 or F33).

Results

The mean (SD) age of the total study population was 54.6 (12.1) years, and 163 926 individuals (71.0%) were female. During a median (IQR) follow-up of 4.1 (2.4-6.2) years, 27 063 participants (20 641 controls and 6422 with RA) developed depression. Participants with RA had a 1.66-fold higher risk of depression compared with controls (adjusted hazard ratio [aHR], 1.66 [95% CI, 1.61-1.71]). The SPRA group (aHR, 1.64 [95% CI, 1.58-1.69]) and the SNRA group (aHR, 1.73 [95% CI, 1.65-1.81]) were associated with an increased risk of depression compared with controls. Patients with RA who used biologic or targeted synthetic DMARDs (aHR, 1.33 [95% CI, 1.20-1.47]) had a lower risk of depression compared with patients with RA who did not use these medications (aHR, 1.69 [95% CI, 1.64-1.74]).

Conclusions and Relevance

This nationwide cohort study found that both SPRA and SNRA were associated with a significantly higher risk of depression. These results suggest the importance of early screening and intervention for mental health in patients with RA.

Early-Onset Ocular Motor Cranial Neuropathy Is a Strong Predictor of Dementia: A Nationwide, Population-Based Cohort Study

PURPOSE

To assess the risk of dementia in individuals with newly diagnosed ocular motor cranial neuropathy (OMCN).

DESIGN

A nationwide, population-based cohort study using authenticated data from the Korean National Health Insurance Service (KNHIS).

PARTICIPANTS

This study included 60 781 patients with OMCN who received a diagnosis between 2010 and 2017 and were followed up through 2018, with an average follow-up of 3.37 ± 2.21 years with a 1-year lag. After excluding patients with disease related to oculomotor dysfunction preceding the OMCN diagnosis, a total of 52 076 patients with OMCN were established. Of these, 23 642 patients who had participated in the National Health Screening Program (NHSP) within 2 years before the OMCN diagnosis were included. After applying the exclusion criteria, the final cohort comprised 19 243 patients and 96 215 age and sex-matched control participants without OMCN.

METHODS

We identified patients with newly diagnosed OMCN in the KNHIS database and collected participant characteristics from the health checkup records of the NHSP. The study end point was determined by the first claim with a dementia diagnostic code and antidementia medications. The association of OMCN with dementia risk was examined using Cox proportional hazards regression analysis, adjusting for potential confounding factors.

MAIN OUTCOME MEASURES

The main outcome measures were hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause dementia (ACD), Alzheimer's disease (AD), and vascular dementia (VaD) development in patients with OMCN relative to those without OMCN.

RESULTS

Patients with newly diagnosed OMCN demonstrated higher metabolic comorbidities than those without OMCN. New OMCN was associated with an elevated risk of ACD (HR, 1.203; 95% CI, 1.113-1.300), AD (HR, 1.137; 95% CI, 1.041-1.243), and VaD (HR, 1.583; 95% CI, 1.286-1.948), independent of potential confounding factors. The younger age groups exhibited a stronger association between OMCN and ACD (HR, 8.690 [< 50 years] vs. 1.192 [≥ 50 years]; P = 0.0004; HR, 2.517 [< 65 years] vs. 1.099 [≥ 65 years]; P < 0.0001).

CONCLUSIONS

This nationwide population-based study assessed the association between OMCN and dementia risk. Our results demonstrated a robust relationship between OMCN and the risk of dementia, particularly in the younger population.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Menopausal hormone therapy and risk for dementia in women with CKD: A nationwide observational cohort study

AIM

The risk for dementia is increased in postmenopausal women. The incidences of premature menopause and dementia have increased in patients with chronic kidney disease (CKD). The potential benefits of hormone replacement therapy (HRT) on cognitive function may be a more critical issue for patients with CKD.

METHODS

Women aged >40 years with or without HRT were identified using the 2009 National Health Screening Questionnaire. Women who were newly diagnosed with CKD between 2009 and 2013 were enrolled. HRT was used as an exposure variable, and participants were followed from the day CKD was diagnosed to December 2019. The hazard ratio (HR) for dementia was evaluated using Cox proportional hazards regression analysis.

RESULTS

We included 755 426 postmenopausal women with CKD. The median follow-up period was 7.3 (IQR, 5.8-8.7) years. All-cause dementia, Alzheimer's disease, and vascular dementia occurred in 107 848 (14.3%), 87 833 (11.6%), and 10 245 (1.4%) women, respectively. HRT was significantly associated with a lower risk for dementia in the adjusted Cox regression model (all-cause dementia: HR 0.80; 95% confidence interval [CI] 0.78-0.82; p < 0.001; Alzheimer's disease: HR 0.80; 95% CI 0.77-0.82; p < 0.001; vascular dementia: HR 0.80; 95% CI 0.74-0.87; p < 0.001).

CONCLUSIONS

HRT was significantly associated with a lower risk for CKD-related cognitive dysfunction in postmenopausal women. Prospective studies are needed to determine whether HRT lowers the risk for dementia in menopausal women with CKD.

Risk of Depression according to Cumulative Exposure to a Low-Household Income Status in Individuals with Type 2 Diabetes Mellitus: A Nationwide Population- Based Study

BACKGRUOUND

We aimed to identify the risk of incident depression according to cumulative exposure to a low-household income status in individuals with type 2 diabetes mellitus (T2DM).

METHODS

For this retrospective longitudinal population-based cohort study, we used Korean National Health Insurance Service data from 2002 to 2018. Risk of depression was assessed according to cumulative exposure to low-household income status (defined as Medical Aid registration) during the previous 5 years among adults (aged ≥20 years) with T2DM and without baseline depression who underwent health examinations from 2009 to 2012 (n=2,027,317).

RESULTS

During an average 6.23 years of follow-up, 401,175 incident depression cases occurred. Advance in cumulative number of years registered for medical aid during the previous 5 years from baseline was associated with an increased risk of depression in a dose-dependent manner (hazard ratio [HR], 1.44 [95% confidence interval (CI), 1.38 to 1.50]; HR, 1.40 [95% CI, 1.35 to 1.46]; HR, 1.42, [95% CI, 1.37 to 1.48]; HR, 1.46, [95% CI, 1.40 to 1.53]; HR, 1.69, [95% CI, 1.63 to 1.74] in groups with 1 to 5 exposed years, respectively). Insulin users exposed for 5 years to a low-household income state had the highest risk of depression among groups categorized by insulin use and duration of low-household income status.

CONCLUSION

Cumulative duration of low-household income status, defined as medical aid registration, was associated with an increased risk of depression in a dose-response manner in individuals with T2DM.

Risk of mortality and cause of death according to kidney function parameters: a nationwide observational study in Korea

BACKGROUND

Further study is warranted to determine the association between estimated glomerular filtration rate (eGFR) or albuminuria and the risk of death from diverse causes.

METHODS

We screened >10 million general health screening examinees who received health examinations conducted in 2009 using the claims database of Korea. After the exclusion of those previously diagnosed with renal failure and those with missing data, 9,917,838 individuals with available baseline kidney function measurements were included. The primary outcome was mortality and cause-specific death between 2009 and 2019 identified through death certificates based on the diagnostic codes of International Classification of Diseases, 10th revision. Multivariable Cox regression analysis adjusted for various clinicodemographic and social characteristics was used to assess mortality risk.

RESULTS

The hazard ratio of death was significantly high in both the eGFR <60 mL/min/1.73 m2 and in the eGFR ≥120 mL/ min/1.73 m2 groups in univariable and multivariable regression analyses when compared to those within the reference range (eGFR of 90-120 mL/min/1.73 m2). The results were similar for death by cardiovascular, cancer, infection, endocrine, respiratory, and digestive causes. We also found that albuminuria was associated with higher risk of death regardless of eGFR range, and those in the higher categories of dipstick albuminuria showed higher risk.

CONCLUSION

We reconfirmed the significant association between eGFR, albuminuria, and mortality. Healthcare providers should keep in mind that albuminuria and decreased eGFR as well as kidney hyperfiltration are independent predictors of mortality.

Association between Cumulative Metabolic Risk Exposure and Cardiovascular Disease: A Nationwide Cohort of Over 3.6 Million Young Adults

AIMS

Since lifetime accumulation of cardiovascular risk factors is getting important, early identification and management of risk factors are emphasised. The global prevalence of metabolic syndrome (MetS), a constellation of these risk factors, is increasing, particularly among young adults. We aimed to investigate the association between cumulative exposure to metabolic risk and cardiovascular disease (CVD) in young adults.

METHODS

In this nationwide population-based cohort, we analysed 3,688,787 young adults (<40 years) with two biennial National Health Screening examinations from 2009 to 2012. Participants were categorised into MetS-free, MetS-developed, MetS-recovered, or MetS-persistent group, based on MetS presence at each examination. The endpoint was new CVD development, including myocardial infarction (MI), and ischaemic stroke.

RESULTS

During follow-up (median, 7.7 years), CVD occurred in 19,219 individuals (0.5%). CVD incidence rates were 0.58, 1.17, 1.20, and 1.83 (1,000 person-year) in the MetS-free, MetS-developed, MetS-recovered, and MetS-persistent groups, respectively. CVD risk was proportionally associated with cumulative metabolic risk exposure, with a maximum 2-fold increase in the MetS-persistent group (aHR 1.94, 95% CI 1.84-2.04), and followed by the MetS-recovered and MetS-developed groups with similar risks. Among the MetS components, persistent exposure to elevated blood pressure (BP) had the greatest association with CVD risk (aHR 1.69, 95% CI 1.63-1.76). This tendency was consistent in the analyses of the risk of MI and ischaemic stroke.

CONCLUSIONS

CVD risk increased in an exposure-dependent manner among young adults. Efforts to optimise cardiometabolic profile, particularly BP, even after the establishment of MetS, might help promote long-term cardiovascular prognosis.

Association between age-related macular degeneration and risk of incident cancer

BACKGROUND/AIMS

Age-related macular degeneration (AMD) and cancer may share similar risk factors, indicating possible common pathogenic pathways. We aimed to describe the site-specific cancer risk based on the relationship of AMD with visual disability (VD) status.

METHODS

This was a population-based cohort study using data from the Korean National Health Insurance Service database (2009-2019) including patients who participated in a national health screening programme in 2009. The subjects were categorised based on the presence of AMD and VD. The occurrence of cancer was identified using principal diagnosis according to the International Classification of Disease, 10th revision codes in claims data. The Cox regression hazard model was used to compare HRs of site-specific cancer.

RESULTS

Among 4 088 814 participants, 51 596 had AMD of which 3683 subjects had VD. The mean follow-up period was 9.6 years. The overall cancer risk was generally null, but the risk of hypervascular cancer such as thyroid cancer (adjusted HR (aHR) 1.10, 95% CI 1.00 to 1.20) and renal cancer (aHR 1.16, 95% CI 1.00 to 1.33) was higher and the risk of stomach cancer (aHR 0.89, 95% CI 0.84 to 0.94) was lower in the AMD group than in the non-AMD group.

CONCLUSION

This study demonstrated a possible association between AMD and several cancers. Increased renal and thyroid cancer risk among patients with AMD could indicate that AMD is associated with hypervascular cancer. Further studies in which additional databases are used and the underlying detailed mechanisms evaluated are needed to validate our results.

Mid- and long-term risk of atrial fibrillation among breast cancer surgery survivors

BACKGROUND

The risk of incident atrial fibrillation (AF) among breast cancer survivors, especially for younger women, and cancer treatment effects on the association remain unclear. This study aimed to investigate the risk of AF among breast cancer survivors and evaluate the association by age group, length of follow-up, and cancer treatment.

METHODS

Using data from the Korean Health Insurance Service database (2010-2017), 113,232 women newly diagnosed with breast cancer (aged ≥ 18 years) without prior AF history who underwent breast cancer surgery were individually matched 1:5 by birth year to a sample female population without cancer (n = 566,160) (mean[SD] follow-up, 5.1[2.1] years). Sub-distribution hazard ratios (sHRs) and 95% confidence intervals (CIs) considering death as a competing risk were estimated, adjusting for sociodemographic factors and cardiovascular/non-cardiovascular comorbidities.

RESULTS

BCS had a slightly increased AF risk compared to their cancer-free counterparts (sHR 1.06; 95% CI 1.00-1.13), but the association disappeared over time. Younger BCS (age < 40 years) had more than a 2-fold increase in AF risk (sHR 2.79; 95% CI 1.98-3.94), with the association remaining similar over 5 years of follow-up. The increased risk was not observed among older BCS, especially those aged > 65 years. Use of anthracyclines was associated with increased AF risk among BCS (sHR 1.57; 95% CI 1.28-1.92), which was more robust in younger BCS (sHR 1.94; 95% CI 1.40-2.69 in those aged ≤ 50 years).

CONCLUSIONS

Our findings suggest that younger BCS had an elevated risk of incident AF, regardless of the length of follow-up. Use of anthracyclines may be associated with increased mid-to-long-term AF risk among BCS.

Increased Risk of Myocardial Infarction, Heart Failure, and Atrial Fibrillation After Spinal Cord Injury

BACKGROUND

Heart diseases are a growing concern for the spinal cord injury (SCI) population.

OBJECTIVES

This study aims to compare the incidence of heart diseases between SCI survivors and the general non-SCI population.

METHODS

We identified 5,083 SCI survivors and 1:3 age- and sex-matched non-SCI controls. Study outcomes were myocardial infarction (MI), heart failure (HF), and atrial fibrillation (AF). The cohort was followed up from the index date (diagnosis date for SCI or corresponding date for matched controls) until 2019.

RESULTS

SCI survivors showed a higher risk for MI (adjusted HR [aHR]: 2.41; 95% CI: 1.93-3.00), HF (aHR: 2.24; 95% CI: 1.95-2.56), and AF (aHR: 1.84; 95% CI: 1.49-2.28) compared to controls. The risks were further increased for those who were registered in the National Disability Registry within 1 year from the index date (SCI survivors with disability): SCI survivors with severe disability had the highest risks of MI (aHR: 3.74; 95% CI: 2.43-5.76), HF (aHR: 3.96; 95% CI: 3.05-5.14), and AF (aHR: 3.32; 95% CI: 2.18-5.05). Cervical and lumbar SCI survivors had an increased risk of heart disease regardless of disability compared to matched controls; these risks were slightly higher in those with disability. Thoracic SCI survivors with disability had significantly increased risk of heart disease compared to matched controls.

CONCLUSIONS

SCI survivors at all levels were at significantly greater risk for heart disease than non-SCI controls, particularly those with severe disability. Clinicians must be aware of the importance of heart disease in SCI survivors.

Associations Between Physical Activity and the Risk of Hip Fracture Depending on Glycemic Status: A Nationwide Cohort Study

CONTEXT

Although physical activity (PA) is recognized to reduce fracture risk, whether its benefits differ according to glycemic status remains unknown.

OBJECTIVE

We investigated the effect of PA on incident hip fracture (HF) according to glycemic status.

METHODS

We studied 3 723 097 patients older than 50 without type 1 diabetes mellitus (DM) or past fractures. HF risks were calculated using Cox proportional hazard regression. Participants were categorized by glycemic status into 5 groups: normal glucose tolerance, impaired fasting glucose, new-onset type 2 DM, type 2 DM less than 5 years, and type 2 DM of 5 years or greater. PA was evaluated using the Korean adaptation of the International Physical Activity Questionnaire Short Form.

RESULTS

The highest HF risk were associated with the lowest PA level (<500 metabolic equivalent task [MET]-min/wk). While similar risks emerged across MET 500 to 1000, 1000 to 1500, and greater than 1500 categories, the relationship showed variations in different glycemic status groups. Exceptions were particularly noted in women with normoglycemia. However, a consistent inverse pattern, with few exceptions, was observed both in men and women with type 2 DM of 5 years or greater. Furthermore, the benefit of PA in the prevention of HFs was most evident in participants with type 2 DM of 5 years or greater. Compared to the reference group (lowest physical activity level <500 MET-min/wk within type 2 DM ≥5 years), the adjusted hazard ratios were 0.74 (0.62-0.88) in men and 0.74 (0.62-0.89) in women, suggesting a significant reduction in risk.

CONCLUSION

Higher PA levels are associated with a lower risk of HF. This protective effect of PA on fracture risk is greatest in patients with DM, particularly in those with DM of 5 years or greater.

Cumulative exposure to metabolic syndrome affects the risk of psoriasis differently according to age group: a nationwide cohort study in South Korea

Late-onset psoriasis is more associated with the cumulative metabolic syndrome burden in the oldest age group, suggesting the particular importance of managing metabolic syndrome in midlife and beyond.

Diabetes duration, cholesterol levels, and risk of cardiovascular diseases in individuals with type 2 diabetes

OBJECTIVE

To investigate the association of diabetes duration with cardiovascular disease (CVD) risk and to examine the relationship between lipid levels and CVD risk over the duration.

METHODS

Using the Korean National Health Insurance Service Cohort database, we identified 2,359,243 subjects with type 2 DM aged ≥20 years in 2015-2016. Baseline lipid levels and diabetes duration were evaluated, and followed up until December 2020 (mean follow-up, 3.9 years). Subjects were categorized according to diabetes duration (new-onset, <5 years, 5-9 years, or ≥10 years). We analyzed the new-onset diabetes group with low-density lipoprotein cholesterol (LDL-C), <70 mg/dL, as the reference group. The hazard ratios (HRs) and 95% confidence intervals (CIs) of myocardial infarction (MI), and ischemic stroke (IS) were estimated using a Cox proportional hazards model adjusted for potential confounders.

RESULTS

During follow-up, 45,883 cases of MI and 53,538 cases of IS were identified. The risk of MI or IS began to increase at LDL-C ≥160 mg/dL in the new-onset diabetes group, and at LDL-C ≥130 mg/dL in the diabetes duration <5 years group. Among subjects with a diabetes duration of 5-9 years, LDL-C 100-129 mg/dL, LDL-C 130-159 mg/dL, and ≥160 mg/dL were significantly associated with the risk of MI, with HRs (95% CI) of 1.13 (1.04-1.22), 1.28 (1.17-1.39), and 1.58 (1.42-1.76), respectively. The risk of MI in the diabetes duration ≥10 years group was increased by 16%, even in the LDL-C 70-99 mg/dL population (HR [95% CI] 1.16 [1.08-1.25]).

CONCLUSIONS

This population-based longitudinal study revealed that the LDL-C cutoff level for increasing the risk of cardiovascular disease varied with diabetes duration, and that the target LDL-C level should depend on the duration.

Metabolic dysfunction-associated fatty liver disease increases the risk of type 2 diabetes mellitus in young Korean adults

AIMS

To investigate the impact of Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD) on the risk of type 2 diabetes mellitus in young Korean adults.

METHODS

Data were sourced from the Korean National Health Insurance Service-Health Screening Cohort, comprising adults aged 20-39 who underwent health examinations between 2009 and 2012. Participants were grouped based on the presence of MAFLD and nonalcoholic fatty liver disease (NAFLD), both individually and in combination. The categorizations included Neither-FLD, NAFLD-only, MAFLD-only, or Both-FLD. Incident diabetes was identified through claims data during the follow-up period.

RESULTS

Among 6,232,656 participants, 676,747 (10.8 %) had MAFLD. During a median follow-up of 9.5 years, 182,291 incident diabetes cases were identified. Multivariate analysis revealed a significantly higher diabetes risk in the MAFLD group compared to those in the Non-MAFLD group (HR = 6.148, 95 % CI, 6.084-6.212). Notably, diabetes incidence was highest in FLI ≥ 60 subgroup with BMI ≥ 23 and metabolic syndrome.

CONCLUSIONS

MAFLD is associated with a 6.1-fold increased diabetes risk in young adults, underscoring the urgent need for early intervention to mitigate this risk.

Does Rheumatoid Arthritis Increase the Risk of COPD?: A Nationwide Retrospective Cohort Study

BACKGROUND

Most reports of pulmonary manifestations in rheumatoid arthritis (RA) have been related to interstitial lung diseases. RA and COPD are both chronic inflammatory systemic diseases.

RESEARCH QUESTION

Does RA increase the risk of developing COPD? Is there a difference between seropositive and seronegative RA in the risk of COPD?

STUDY DESIGN AND METHODS

Using the Korean National Health Insurance Database, we screened individuals diagnosed with RA between 2010 and 2017. We identified 46,030 patients with RA (32,608 with seropositive RA and 13,422 with seronegative RA) and 230,150 matched control individuals; we monitored them until December 2019. We used multivariate Cox proportional hazard models to estimate the adjusted hazard ratio (aHR) of risk factors for the development of COPD.

RESULTS

The incidence of COPD among patients with RA was 5.04 per 1,000 person-years; it was 2.23 per 1,000 person-years in the control group. Patients with RA showed a higher risk of developing COPD (aHR, 2.11; 95% CI, 1.96-2.28) compared with the control group. Although both seropositive RA and seronegative RA were associated with an increased risk of COPD, patients with seropositive RA had a higher risk for the development of COPD (aHR, 1.26; 95% CI, 1.09-1.46) than patients with seronegative RA. In the subgroup analyses, smoking history did not demonstrate significant interactions between RA and COPD development.

INTERPRETATION

RA was shown to be associated with an increased risk of COPD development, augmented by seropositivity. Physicians should monitor respiratory symptoms and pulmonary function carefully in patients with RA.

Ocular Motor Cranial Nerve Palsies and Increased Risk of Primary Malignant Brain Tumors: South Korean National Health Insurance Data

The aim of this study was to investigate the association between ocular motor cranial nerve palsies (OMCNP) and the occurrence of primary malignant brain tumors in a Korean population, using the national sample cohort database from Korea National Health Insurance Service (KNHIS). KNHIS data between 2010 and 2017 were analyzed. Our sample encompassed 118,686 participants, including 19,781 from a recently diagnosed OMCNP cohort and 98,905 from a matched control cohort through a 1:5 propensity score matching based on age and gender. To counteract the issue of reverse causation, we integrated a one-year time lag in our sensitivity analysis. Study participants were followed up until 31 December 2019. Cox proportional hazard regression analysis was used to compute the adjusted hazard ratio (HR) for primary malignant brain tumors according to the OMCNP diagnosis. Additionally, we performed a subgroup analysis to discern effects of various factors on the association between OMCNP and primary malignant brain tumors. HR for primary malignant brain tumors was 3.272 (95% confidence interval [CI]: 2.294 to 4.665) in the OMCNP cohort compared to the control cohort in a fully adjusted model for age, sex, socio-economic status, smoking, drinking, regular physical exercise, hypertension, diabetes, dyslipidemia, obesity, chronic kidney disease, and human immunodeficiency virus infection. Further subgroup analysis revealed that the risk of primary malignant brain tumors was significantly increased in women with OMCNP compared to men with OMCNP (HR: 5.118 in women vs. 2.441 in men, p = 0.0440), and in those aged <65 years than in those aged ≥65 years (HR: 6.951 in age < 65 years vs. 1.899 in age ≥ 65 years, p = 0.0006). Our population-based cohort study demonstrated a significantly increased risk of subsequent primary malignant brain tumors in patients with OMCNP. Particularly, OMCNP-afflicted women aged below 65 manifested a heightened probability of developing primary malignant brain tumors compared to those devoid of OMCNP.

Association of non-alcoholic fatty liver disease with cardiovascular disease and all cause death in patients with type 2 diabetes mellitus: nationwide population based study

OBJECTIVE

To investigate the risk of non-alcoholic fatty liver disease (NAFLD) for cardiovascular disease and all cause death in patients with type 2 diabetes mellitus (T2DM).

DESIGN

Nationwide population based study.

SETTING

Longitudinal cohort study in Korea.

PARTICIPANTS

7 796 763 participants in the National Health Screening Programme in 2009 were divided into three groups based on NAFLD status: no NAFLD (fatty liver index<30); grade 1 NAFLD (30≤fatty liver index<60); and grade 2 NAFLD (fatty liver index≥60). Median follow-up was 8.13 years.

MAIN OUTCOME MEASURES

The primary outcome was incident cardiovascular disease (myocardial infarction, ischaemic stroke) or all cause death.

RESULTS

Of 7 796 763 participants, 6.49% (n=505 763) had T2DM. More patients with T2DM had grade 1 NAFLD (34.06%) and grade 2 NAFLD (26.73%) than those without T2DM (grade 1 NAFLD: 21.20%; grade 2 NAFLD: 10.02%). The incidence rate (per 1000 person years) of cardiovascular disease and all cause death increased in the order of no NAFLD, grade 1 NAFLD, and grade 2 NAFLD, and the incidence rates in patients with T2DM were higher than those in patients without T2DM. The five year absolute risk for cardiovascular disease and all cause death increased in the order of no NAFLD, grade 1 NAFLD, and grade 2 NAFLD in patients without and with T2DM (no NAFLD, without T2DM: 1.03, 95% confidence interval 1.02 to 1.04, and 1.25, 1.24 to 1.26, respectively; grade 1 NAFLD, without T2DM: 1.23, 1.22 to 1.25, and 1.50, 1.48 to 1.51, respectively; grade 2 NAFLD, without T2DM: 1.42, 1.40 to 1.45, and 2.09, 2.06 to 2.12, respectively; no NAFLD, with T2DM: 3.34, 3.27 to 3.41, and 3.68, 3.61 to 3.74, respectively; grade 1 NAFLD, with T2DM: 3.94, 3.87 to 4.02, and 4.25, 4.18 to 4.33, respectively; grade 2 NAFLD, with T2DM: 4.66, 4.54 to 4.78, and 5.91, 5.78 to 6.05, respectively). Patients with T2DM and without NAFLD had a higher five year absolute risk for cardiovascular disease and all cause death than those without T2DM and with grade 2 NAFLD. Risk differences for cardiovascular disease and all cause death between no NAFLD and grade 1 or grade 2 NAFLD were higher in patients with T2DM than in those without T2DM.

CONCLUSIONS

NAFLD in patients with T2DM seems to be associated with a higher risk of cardiovascular disease and all cause death, even in patients with mild NAFLD. Risk differences for cardiovascular disease and all cause death between the no NAFLD group and the grade 1 or grade 2 NAFLD groups were higher in patients with T2DM than in those without T2DM.

The risk of fracture in age-related macular degeneration according to the presence of visual disability: a nationwide cohort study

PURPOSE

To evaluate the association between age-related macular degeneration (AMD) with or without visual disability (VD) and the risk of fracture using the National Health Insurance data in South Korea.

METHODS

In total, 3,894,702 individuals who had taken part in health-screening programs between January 1, 2009, and December 31, 2009, were included in the cohort and followed until December 31, 2019. The participants with VD, which could be related to the severity of AMD, were defined as those with a loss of vision or visual field defect as certified by the Korean government's Ministry of Health and Welfare. The hazard ratio was calculated for groups (control and AMD with/without VD) using the multivariable-adjusted cox regression analysis.

RESULTS

In total, 466,890 participants (11.99%) were diagnosed with fractures during the study period. An increased risk of fracture was observed in individuals with AMD compared with the control (adjusted hazard ratio (aHR), 1.09, 95% confidence interval (CI), 1.06-1.11). Furthermore, among the AMD individuals, an increased risk of fracture was prominent in individuals with VD (aHR 1.17, 95% CI 1.08-1.27) than those without VD (aHR 1.08, 95% CI 1.06-1.11) compared with the reference group (control).

CONCLUSIONS

AMD was associated with an increased risk of fracture even without VD. Prevention for fracture should be considered in AMD patients, especially when accompanied by VD.

Cumulative exposure to hypertriglyceridemia and risk of type 2 diabetes in young adults

AIM

This study aimed to examine whether cumulative exposure to hypertriglyceridemia is associated with an increased risk of developing type 2 diabetes in young adults.

METHODS

The study included 1,840,251 participants aged 20-39 years who had undergonefourconsecutiveannualhealth checkups and had no history of type 2 diabetes. Participants werecategorized into five groups (exposure score 0-4) based on the frequencies of hypertriglyceridemia diagnosis over a four-year period. The primary outcome was newly diagnosed type 2 diabetes. Exploratory analyses were performed for the different subgroups.

RESULTS

During a follow-up period of 6.53 years, 40,286 participants developed type 2 diabetes. The cumulative incidence of type 2 diabetes significantly increased with higher exposure scores for hypertriglyceridemia (log-rank test, P < 0.001). The multivariable-adjusted hazard ratios for incident diabetes were 1.674 (95 % CI, 1.619, 1.732), 2.192 (95 % CI, 2.117, 2.269), 2.637 (95 % CI, 2.548, 2.73), and 3.715 (95 % CI, 3.6, 3.834) for participants with scores of 1-4, respectively, compared with those with an exposure score of 0.

CONCLUSIONS

In this large-scale prospective cohort study of young adults, cumulative exposure to hypertriglyceridemia was significantly associated with an increased risk of type 2 diabetes, independent of lifestyle-related factors.

Rheumatoid Arthritis and Risk of Lung Cancer: A Nationwide Cohort Study

INTRODUCTION

There has been an increasing interest in the risk of lung cancer related to rheumatoid arthritis (RA). We investigated the association between RA and the risk of lung cancer with consideration of key confounding factors, including RA serostatus and smoking status.

METHODS

Using a nationwide database, we identified 51,899 patients with newly diagnosed RA between 2010 and 2017, which were matched by sex and age at a 1:5 ratio with 259,495 non-RA population. The association of lung cancer and RA was investigated using Cox regression analyses. Stratified analyses by smoking status, sex, age, and comorbidity of interstitial lung disease were conducted using the same Cox modeling.

RESULTS

During 4.5 years of follow-up, the adjusted hazard ratio of lung cancer in the patients with RA was 1.49 (95% confidence interval: 1.34-1.66). Compared with the patients with seronegative RA, an increased risk of lung cancer was not considerable in the patients with seropositive RA. In the stratified analyses, the increased risk of lung cancer was more prominent in current or previous heavy smokers with RA (interaction p value of 0.046) and male patients (interaction p < 0.001), whereas there was no substantial effect associated with age or interstitial lung disease status.

CONCLUSIONS

Patients with RA had an increased risk of lung cancer compared with the non-RA group, and the risk did not differ by RA serostatus. There is a need for increased awareness of smoking cessation and potentially for regular lung cancer screening with proper risk stratification in patients with RA.