Mediators of the Effect of Obesity on Stroke and Heart Disease Risk: Decomposing Direct and Indirect Effects.

BACKGROUND: The prevalence of overweight and obesity are well known risk factors of atherosclerotic cardiovascular disease (ASCVD). We aimed to examine the association between body mass index (BMI) and ASCVD over a 23-year follow-up in young adults. We also qualified how much of the effects of obesity on ASCVD were mediated through blood pressure, cholesterol, and glucose. METHODS: Data are from the Korean Life Course Health Study, a cohort study of 226,955 Korean young adults aged 20-39. At baseline, the participants undertook routine health assessments where their BMI was measured in 1992-1994; and the metabolic mediators including systolic blood pressure (SBP), fasting serum glucose (FSG), and total cholesterol (TC) were re-measured in 2002-2004. The main outcomes of the study include incident events of ischemic heart disease (IHD), stroke, and ASCVD between 2005 and 2015. Cox proportional model was used to calculate adjusted hazard ratios (HRs) for ASCVD. RESULTS: In both men and women, the direct effect of BMI on ASCVD was greater than the indirect effect. The percentage of excess HR of BMI mediated by all of the metabolic mediators, including SBP, FSG, and TC, was 45.7% for stroke and 18.7% for IHD in men and 27.5% for stroke and 17.6% for IHD in women. CONCLUSION: High BMI in young adults increases the risk of metabolic mediators in their middle age, and metabolic mediators explain the adverse effects of high BMI on stroke risk than IHD risk.

The Insignificant Correlation between Androgen Deprivation Therapy and Incidence of Dementia Using an Extension Survival Cox Hazard Model and Propensity-Score Matching Analysis in a Retrospective, Population-Based Prostate Cancer Registry.

This study aims to evaluate the effect of androgen-deprivation therapy (ADT) on the incidence of dementia, after considering the time-dependent survival in patients with prostate cancer (PC) using a Korean population-based cancer registry database. After excluding patients with cerebrovascular disease and dementia before or within the 3-month-ADT and those with surgical castration, 9880 (19.3%) patients were matched into ADT and non-ADT groups using propensity-score matching (PSM) among 51,206 patients registered between 2006 and 2013. To define the significant relationship between ADT duration and the incidence of dementia, the extension Cox proportional hazard model was used with p-values < 0.05 regarded as statistically significant. The mean age and survival time were 67.3 years and 4.33 (standard deviation [SD] 2.16) years, respectively. A total of 2945 (9.3%) patients developed dementia during the study period, including Parkinson's (11.0%), Alzheimer's (42.6%), vascular (18.2%), and other types of dementia (28.2%). Despite PSM, the PC-treatment subtypes, survival rate, and incidence of dementia significantly differed between the ADT and non-ADT groups (p < 0.05), whereas the rate of each dementia subtype did not significantly differ (p = 0.069). A multivariate analysis for dementia incidence showed no significance of ADT type or use duration among patients with PC (p > 0.05), whereas old age, obesity, regional SEER stage, a history of cerebrovascular disease, and a high Charlson Comorbidity Index were significant factors for dementia (p < 0.05). Insignificant correlation was observed between ADT and the incidence of dementia based on the extension survival model with PSM among patients with PC.

Validation of Cancer Diagnosis Based on the National Health Insurance Service Database versus the National Cancer Registry Database in Korea.

PURPOSE: This study aimed to assess the feasibility of operational definitions of cancer patients in conducting cancer-related studies using the claims data from the National Health Insurance Service (NHIS). MATERIALS AND METHODS: Cancer incidence data were obtained from the Korean Central Cancer Registry, the NHIS primary diagnosis, and from the rare and intractable disease (RID) registration program. RESULTS: The operational definition with higher sensitivity for cancer patient verification was different by cancer type. Using primary diagnosis, the lowest sensitivity was found in colorectal cancer (91.5%; 95% confidence interval [CI], 91.7 to 92.0) and the highest sensitivity was found in breast cancer (97.9%; 95% CI, 97.8 to 98.0). With RID, sensitivity was the lowest in liver cancer (91.9%; 95% CI, 91.7 to 92.0) and highest in breast cancer (98.1%; 95% CI, 98.0 to 98.2). In terms of the difference in the date of diagnosis in the cancer registration data, > 80% of the patients showed a < 31-day difference from the RID definition. CONCLUSION: Based on the NHIS data, the operational definition of cancer incidence is more accurate when using the RID registration program claims compared to using the primary diagnosis despite the relatively lower concordance by cancer type requires additional definitions such as treatment.

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

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

Survival in untreated hepatocellular carcinoma: A national cohort study.

This study aimed to analyze the proportion, characteristics and prognosis of untreated hepatocellular carcinoma (HCC) patients in a large representative nationwide study. A cohort study was conducted using the National Health Insurance Service (NHIS) database in Korea. A total of 63,668 newly-diagnosed HCC patients between January 2008 and December 2013 were analyzed. Patients were categorized into treatment group and no treatment group using claim codes after HCC diagnosis. The proportion of untreated HCC patients was 27.6%, decreasing from 33.4% in 2008 to 24.8% in 2013. Compared to treated patients, untreated patients were more likely to be older (P < 0.001), female (P < 0.01), to have a distant SEER stage (P < 0.001), severe liver disease (P < 0.001), and lower income (P < 0.001). The fully-adjusted hazard ratio for all-cause mortality comparing untreated to treated patients was 3.11 (95% CI, 3.04-3.18). The risk of mortality was higher for untreated patients in all pre-defined subgroups, including those with distant SEER stage and those with severe liver disease. About one fourth of newly diagnosed HCC patients did not receive any HCC-specific treatment. Untreated patients showed higher risk of mortality compared to treated patients in all subgroups. Further studies are needed to identify obstacles for HCC treatment and to improve treatment rates.

Trajectory of smoking and early bladder cancer risk among Korean young adult men.

OBJECTIVES: The aim of this study was to examine the risk of bladder cancer according to the trajectory pattern of amount of smoking among Korean young adult men. METHODS: Smoking status was assessed with a standardized questionnaire in the Korean Life Course Health Study (KLCHS). Trajectory analyses were performed among young adult men using seven repeated surveys of cigarette per day (CPD) every two years from 1992 to 2005. The occurrence of bladder cancer was tracked from 2006 to 2016. The Cox proportional models were used to calculate the hazard ratio (HR) (95% confidence interval) of smoking patterns on bladder cancer. RESULTS: The mean (standard deviation) age of the 161,069 participants was 34.0 (3.9) years, and 2,280,143 person-years (PY) were examined during the follow-up period of 14.2 (median 14.3) years. During this period, 263 new cases of bladder cancer occurred (11.5/100,000 PY). Among the six trajectory groups (low steady, lowering, rise and fall, high steady, rise and sharp fall, and very high steady), there was a higher risk of developing bladder cancer in the all the other groups compared to the low steady group. The highest risk group was the very high steady group, with HR 2.83 (95% CI 1.79-4.49). In addition, the risk of bladder cancer was 2.61 (95% CI 1.50-4.54) in the rise and sharp fall group. CONCLUSION: The risk of bladder cancer did not show much difference according to trajectories, except for low steady group. Thus quitting smoking should be the priority to lower the risk of bladder cancer in smokers.

Use of Gadoxetic Acid-enhanced Liver MRI and Mortality in More than 30 000 Patients with Hepatocellular Carcinoma: A Nationwide Analysis.

Background The impact on survival of gadoxetic acid-enhanced MRI in addition to multiphase contrast material-enhanced CT for initial staging in patients with hepatocellular carcinoma (HCC) is unknown. Purpose To compare all-cause mortality in patients with HCC who underwent CT only, CT plus non-gadoxetic acid-enhanced MRI, or CT plus gadoxetic acid-enhanced MRI as part of their initial diagnostic work-up. Materials and Methods The authors performed a nationwide retrospective cohort study of patients diagnosed with HCC in South Korea between January 2008 and December 2010. Follow-up extended through December 2014. The primary outcome was all-cause mortality. Cox proportional hazards regression model with adjustment of confounding factors was used to estimate hazard ratios (HRs) for all-cause mortality. Results Among 30 023 patients with HCC (mean age ± standard deviation, 58.5 years ± 10.7, 23 978 men), the proportions of patients in whom HCC was diagnosed using CT only, CT plus non-gadoxetic acid-enhanced MRI, and CT plus gadoxetic acid-enhanced MRI were 56.1%, 12.9%, and 31.0%, respectively. In adjusted analysis using CT only as the reference category, the HR for mortality for CT plus gadoxetic acid-enhanced MRI was 0.64 (95% confidence interval [CI]: 0.62, 0.67; P < .001), and the HR for CT plus non-gadoxetic acid-enhanced MRI was 0.71 (95% CI: 0.68, 0.75; P < .001). Use of CT plus gadoxetic acid-enhanced MRI was associated with lower mortality compared with CT plus non-gadoxetic acid-enhanced MRI (adjusted HR, 0.90; 95% CI: 0.85, 0.95; P < .001), but this survival advantage was restricted to patients with localized disease. Conclusion In patients with hepatocellular carcinoma, additional use of contrast-enhanced MRI was associated with lower mortality. Furthermore, CT plus gadoxetic acid-enhanced MRI was associated with better survival than CT plus non-gadoxetic acid-enhanced MRI but only in patients with localized disease. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Kim in this issue.

Radiotherapy can increase the risk of ischemic cerebrovascular disease in head and neck cancer patients: A Korean population-based cohort study.

BACKGROUND AND PURPOSE: Several reports suggested that radiotherapy (RT) was related to an increased risk of cerebrovascular disease (CVD) in head and neck cancer (HNC) patients, but other risk factors of CVD were not properly considered in estimating the risk of RT. The purpose of this study is to analyze the effect of RT on the risk of CVD in HNC patients. MATERIALS AND METHODS: The Korean Central Cancer Registry data and Korean National Health Insurance Service data were used. A total of 5570 patients with newly diagnosed HNC between the years 2003-2005 was included in our study cohort. We analyzed the effect of treatment modality and other socioeconomic variables on ischemic CVD incidence using the Cox proportional hazard regression model both in the entire cohort (n = 5570) and in the propensity score matching (PSM) cohort (n = 3310). RESULTS: RT increased the CVD risk by 40.8% (aHR: 1.408, p = 0.006) in the entire cohort and by 44.3% (aHR: 1.443, p = 0.047) in the PSM cohort, respectively. CONCLUSION: The risk of ischemic CVD increased by RT after adjusting for other socioeconomic and clinical risk factors. Regular follow up and appropriate screening for CVD are required for HNC patients who received RT, and focus should be on advanced-age patients with a low socioeconomic status and known clinical risk factors of CVD.

High-resolution metabolomics study revealing l-homocysteine sulfinic acid, cysteic acid, and carnitine as novel biomarkers for high acute myocardial infarction risk.

BACKGROUND: Identifying changes in serum metabolites before the occurrence of acute myocardial infarction (AMI) is an important approach for finding novel biomarkers of AMI. METHODS: In this prospective cohort study, serum samples obtained from patients at risk of AMI (n = 112) and non-risk controls (n = 89) were tested using high-resolution metabolomics (HRM). Partial least-squares discriminant analysis (PLS-DA), along with univariate analysis using a false discovery rate (FDR) of q = 0.05 were performed to discriminate metabolic profiles and to determine significantly different metabolites between healthy control and AMI risk groups. RESULTS: PLS-DA significantly separated the AMI risk sera from control sera. The metabolites associated with amino acid biosynthesis, 2-oxocarboxylic acid, tryptophan, and amino sugar and nucleotide sugar metabolism pathways were mainly elevated in patients at risk of AMI. Further validation and quantification by MS/MS showed that tryptophan, carnitine, L-homocysteine sulfinic acid (L-HCSA), and cysteic acid (CA) were upregulated, while L-cysteine and L-cysteine sulfinic acid (L-CSA) were downregulated, specifically among AMI risk sera. Additionally, these discriminant metabolic profiles were not related to hypertension, smoking or alcoholism. CONCLUSION: In conclusion, detecting upregulated L-HCSA and CA along with carnitine among patients at risk for AMI could serve as promising non-invasive biomarkers for early AMI detection.

Causal Associations Between Serum Bilirubin Levels and Decreased Stroke Risk: A Two-Sample Mendelian Randomization Study.

OBJECTIVE: A number of epidemiological studies have reported that decreased serum bilirubin, an endogenous antioxidant, is associated with cardiovascular disease. However, previous Mendelian randomization analyses conducted using a single sample have shown no evidence of association. Approach and Results: A 2-sample summary Mendelian randomization study was performed by obtaining exposure and outcome data from separate nonoverlapping samples. We utilized data from the KoGES (Korean Genome and Epidemiology Study; n=25 406) and KCPS-II (Korean Cancer Prevention Study-II; n=14 541) biobank for serum bilirubin and stroke, respectively. Using KoGES, a total of 1784 single nucleotide polymorphisms associated with serum bilirubin levels were discovered using a genome-wide significance threshold (P<5×10-8), of which 10 single nucleotide polymorphisms were identified as independent (R2<0.005) and adopted as genetic instruments. From KCPS-II, total and ischemic stroke cases were identified (n=1489 and n=686), with 12 366 acting as controls. Various 2-sample summary Mendelian randomization methods were employed, with Mendelian randomization estimates showing an inverse causal association between serum bilirubin levels and total stroke risk (odds ratio, 0.481 [95% CI, 0.234-0.988]; P=0.046). This association increased in magnitude when restricting the analysis to ischemic stroke cases (odds ratio, 0.302 [95% CI, 0.105-0.868]; P=0.026). CONCLUSIONS: Our findings provide evidence of significant causal relationship between high levels of bilirubin and decreased stroke risk in Korean population in agreement with observational approaches. This highlights the potential for bilirubin to serve as a therapeutic target for oxidative stress-related diseases such as stroke and suggests that previous findings were not a consequence of unmeasured confounding.

Trajectory of Smoking and Incidence of Atherosclerotic Cardiovascular Disease among Korean Young Adult Men.

Introduction: Smoking among young adults is associated with atherosclerotic cardiovascular disease (ASCVD) in middle age. Our aim was to analyze the trajectory of smoking in young adults and analyze the effects of the trajectory group on incident ASCVD. Methods: This study was conducted among 60,709 young adult men aged 20-29 years who received health screening every two years from 1992-2004. Trajectory analysis was performed through smoking survey data measured 7 times during this period. ASCVD, including ischemic heart disease (IHD) and stroke events were confirmed from 2005-2015. The association between the trajectory group and ASCVD risk was analyzed using Cox proportional hazard models, controlling for covariates and mediators. Results: Trajectory analysis showed that smoking categorized into five groups as follows: Group 1 (28.3%), low steady; Group 2 (14.7%), lowering; Group 3 (17.3%), high steady; Group 4 (15.6%), rise and fall; and Group 5 (24.2%), very high steady. The model performance of the trajectory model (Akaike information criterion; AIC = 51,670.78) with mediators was better than the model (AIC = 51,847.85) without mediators. Group 5 showed a 49% higher risk of ASCVD than Group 1. The risk of IHD was 1.63-times higher for Group 5 and 1.31-times higher for Group 4, compared to Group 1. Compared to Group 1, Group 5 had a 1.36- and 1.58-times higher risk for total stroke and ischemic stroke, respectively. Conclusions: In young adult men, the multiple measured trajectory model with mediators was far more informative than one-time smoking for explaining the association with cardiovascular disease.

Smoking and atherosclerotic cardiovascular disease risk in young men: the Korean Life Course Health Study.

OBJECTIVE: To examine the effect of smoking on risk of atherosclerotic cardiovascular disease (ASCVD) in Korean young men and to examine whether serum total cholesterol levels could modify the effect of smoking on ASCVD. DESIGN: A prospective cohort study within a national insurance system. SETTING: Health screenings provided by national insurance in 1992 and 1994. PARTICIPANTS: A total of 118 531 young men between 20 and 29 years of age and were followed up for an average of 23 years. OUTCOME MEASURE: To assess the independent effects of smoking on the risk of ischaemic heart disease (IHD), stroke and ASCVD, Cox proportional hazards regression models were used, controlling for age, hypertension, diabetes, hypercholesterolaemia and alcohol drinking. RESULTS: The total number of current smokers was 78 455 (66.2%), and 94 113 (79.7%) of the sample recorded a total cholesterol level <200 mg/dL measured at baseline. Between 1993 and 2015, 2786 cases of IHD (53/100 000 person year), 2368 cases of stroke (45.4/100 000 person year) and 6368 ASCVD (122.7/100 000 person year) occurred. The risk of IHD, stroke and total ASCVD events was found to increase for current smokers, with a HR with 95% CI of 1.5 (95% CI 1.3 to 1.6), 1.4 (95% CI 1.2 to 1.6) and 1.4 (95% CI 1.3 to 1.5), respectively. Furthermore, the risks above were also found throughout the range of serum levels of cholesterol. CONCLUSIONS: Smoking among Korean young adult men was independently associated with increased risk of IHD, stroke and ASCVD. The concentration of cholesterol in Korean men did not modify the effect of smoking on ASCVD.

Systemic inflammation and suicide risk: cohort study of 419 527 Korean men and women.

BACKGROUND: Data from only one study have been used to examine the relationship between systemic inflammation and later suicide risk, and a strong positive association was apparent. More research is needed, particularly looking at gender, not least because women are seemingly more vulnerable to inflammation-induced mood changes than men. METHODS: The Korean Cancer Prevention Study had a cohort of over 1 million individuals aged 30-95 years at baseline examination between 1992 and 1995, when white blood cell count, our marker of systemic inflammation, was assessed. RESULTS: A mean of 16.6 years of mortality surveillance gave rise to 1010 deaths from suicide in 106 643 men, and 1019 deaths from suicide in 312 884 women. There was little evidence of an association between our inflammation marker and suicide mortality in men after multiple adjustments. In women, however, those in the second inflammation quartile and higher experienced around 30% increase risk of death (HR 1.35; 95% CI: 1.11-1.64). CONCLUSIONS: Higher levels of systemic inflammation were moderately related to an elevated risk of suicide death in women but not in men.

Oral health and later coronary heart disease: Cohort study of one million people.

Aims Systematic reviews report an association between poorer oral health and an increased risk of coronary heart disease. This contentious relationship may not be causal but existing studies have been insufficiently well powered comprehensively to examine the role of confounding, particularly by cigarette smoking. Accordingly, we sought to examine the role of smoking in generating the relationship between oral health and coronary heart disease in life-long non-smokers. Methods and results In the Korean Cancer Prevention Study, 975,685 individuals (349,579 women) aged 30-95 years had an oral examination when tooth loss, a widely used indicator of oral health, was ascertained. Linkage to national mortality and hospital registers over 21 years of follow-up gave rise to 64,784 coronary heart disease events (19,502 in women). In the whole cohort, after statistical adjustment for age, there was a moderate, positive association between tooth loss and coronary heart disease in both men (hazard ratio for seven or more missing teeth vs. none; 95% confidence interval 1.08; 1.02, 1.14; Ptrend across tooth loss groups <0.0001) and women (1.09; 1.01, 1.18; Ptrend 0.0016). Restricting analyses to a subgroup of 464,145 never smokers (25,765 coronary heart disease events), however, resulted in an elimination of this association in men (1.01; 0.85, 1.19); Ptrend 0.7506) but not women (1.08; 0.99, 1.18; Ptrend 0.0086). Conclusion In men in the present study, the relationship between poor oral health and coronary heart disease risk appeared to be explained by confounding by cigarette smoking so raising questions about a causal link.

The J-curve between Diastolic Blood Pressure and Risk of All-cause and Cardiovascular Death.

BACKGROUND AND OBJECTIVES: The J-curve phenomenon between diastolic blood pressure (DBP) and mortality has been reported repeatedly in treated patients. However, the baseline risk of low DBP has not been fully explored. This study was to examine the relationship between DBP and risk of mortality from all-cause, atherosclerotic vascular diseases (ASCVD), and ischemic heart disease (IHD) using a prospective cohort of general population. METHODS: We analyzed 1,234,435 participants of the Korean Cancer Prevention Study cohort (789,255 men, 30-95 years of age) who had a medical evaluation from 1992 to 1995 using Cox proportional hazards models. RESULTS: A total of 22.5 million person-years were followed up (mean age 46.6 years, deaths 193,903 cases). The hazard ratios of mortality from all-cause and ASCVD, among those with DBP <60 mmHg compared to 70-79 mmHg were 1.23 (95% confidence interval [CI], 1.16-1.30) and 1.37 (95% CI, 1.20-1.57), respectively, after adjustment for multivariable including systolic blood pressure. Increased risks of all-cause death in the lowest DBP category group were maintained in men or women, 30-59 or ≥60 years of age, smoker or non-smoker and diabetes mellitus (DM) or non-DM subgroups. The risk in DBP 60-69 mmHg groups increased in several subgroups. However, the risk for ASCVD death in 30-59 years and DM group, and risk for IHD death in most subgroups except for elderly (≥60 years) decreased. CONCLUSION: A J-curve relationship between low DBP and all-cause death was found consistently. The baseline risk in the general population may be considered for risk assessment, particularly in case of interventions that lower DBP below 60 mmHg.

Prediagnosis Body Mass Index and Risk of Secondary Primary Cancer in Male Cancer Survivors: A Large Cohort Study.

Purpose Male cancer survivors have a higher risk of cancer than the general population, which might be caused by an increased prevalence of obesity or susceptibility to obesity-related carcinogenesis. We assessed the effects of obesity before the diagnosis of a first cancer on the development of secondary primary cancers (SPCs). Methods The study population consisted of 239,615 Korean male cancer survivors between January 2003 and December 2010. Incident SPCs were assessed throughout follow-up until December 2011. Cox proportional hazards models were used to calculate the hazard ratios of SPCs associated with prediagnosis body mass index (BMI), which were compared with those of first cancers in all cohort participants. Results After 1,614,583 person-years of follow-up, we observed 4,799 patients with SPC. The age-standardized incidence rate of cancer in cancer survivors was 1.1 times higher than that of the general population. We found positive linear trends between prediagnosis BMI and risk of all-combined, colorectal, liver, lymphoma, biliary tract, kidney, and obesity-related SPCs. The magnitude of the BMI-SPC risk association in male cancer survivors was stronger than that for first cancers in the general population, whereas the mean BMI was similar in both groups. In the severely obese category (BMI ≥ 30 kg/m2), the adjusted hazard ratios for SPCs among cancer survivors (1.41; 95% CI, 1.15 to 1.74) were significantly higher than those for first cancers among all cohort participants (1.12; 95% CI, 1.09 to 1.16; Pheterogeneity < .01). Conclusion Prediagnosis obesity is a risk factor for overall and individual SPCs, and the strength of the BMI-cancer association is slightly stronger in male cancer survivors than in the general population.

Clinical Conversion or Reversion of Mild Cognitive Impairment in Community versus Hospital Based Studies: GDEMCIS (Gwangju Dementia and Mild Cognitive Impairment Study) and CREDOS (Clinical Research Center for Dementia of South Korea).

BACKGROUND: In keeping with increasing interest in dementia, few recent studies suggest that clinical course of mild cognitive impairment vary across different studies with hospital-based subjects showing higher rates of conversion than community-based subjects. OBJECTIVE: The main objective of the present study was to assess whether the clinical conversion or reversion rates differ according to recruitment source. METHODS: The baseline study subjects comprised of patients who were diagnosed with mild cognitive impairment in community-based GDEMCIS or hospital-based CREDOS. The two studies had nearly the same protocol and were performed over a similar period. We used propensity score matching for baseline comparability. After that, Cox proportional hazards regression analyses were conducted to estimate the hazard ratios and 95% confidence intervals of clinical conversion or reversion. RESULTS: Based on 89 GDEMCIS subjects, 1 : 4 propensity score matching was conducted and 356 CREDOS subjects were selected. After adjusting for covariates including baseline demographics, comorbidity, depression, disability, and neuropsychological result, Cox proportional hazard regression analysis for time to clinical conversion indicated that recruitment from hospital-based CREDOS exhibited hazard ratio of 2.13 (95% CI, 1.08-4.21), as compared to recruitment from community-based GDEMCIS. Similarly, Cox proportional hazard regression analysis for time to reversion indicated that recruitment from hospital-based CREDOS exhibited hazard ratio of 0.34 (95% CI, 0.20-0.59), as compared to recruitment from community-based GDEMCIS. CONCLUSION: The present study demonstrated that even after the matching process and adjustments for baseline covariates, recruitment source greatly affected the course of mild cognitive impairment.

Hazard Ratio of Smoking on Lung Cancer in Korea According to Histological Type and Gender.

PURPOSE: Using nationwide cancer incidence data, we examined whether the strength of the association of cigarette smoking with lung cancer risk differs according to major histological type and gender, taking account of other risk factors in the Korean population. METHODS: The study population derived from government employees and teachers aged 20 years and over who participated in a national health examination program in 1998 or 1999. Total study subjects were 1,357,447. After excluding 1556 subjects who were treated with lung cancer during 1998-2000, we restricted our analysis to 1,355,891 cases. We followed up those 1,355,891 subjects who were cancer-free at baseline until December 31, 2010. The incident cancer cases were identified from the Korea Central Cancer Registry, which is a nationwide hospital-based cancer registry system that includes 94 % of the university hospitals and 96 % of the resident training hospitals of the country. RESULTS: A higher risk for having ever smoked was observed for squamous-cell and small-cell carcinoma in both men and women. Heavy and long-term smokers were at higher risk for these carcinomas. Significant associations with quantity and duration-related factors were observed mainly among men. These findings indicate that smoking is closely related to the risk of squamous-cell and small-cell carcinoma among women as well as men. However, the magnitude of smoking-related lung cancer risk is likely to differ between men and women. CONCLUSION: The hazard ratios for all types of lung cancer were significantly higher in male current smokers than in male never smokers. In case of women, the hazard ratios for adenocarcinoma were not different between current smokers and never smokers. The hazard ratios we found, however, were lower than those reported in Western countries and in Korea, but consistent with those reported in North-eastern Asian countries.

Frontal Lobe Function and Risk of Hip Fracture in Patient With Alzheimer Disease: An Analysis of Linked Data.

To determine the association between frontal lobe function and risk of hip fracture in patients with Alzheimer disease (AD).Retrospective cohort study using multicenter hospital-based dementia registry and national health insurance claim data was done. Participants who had available data of neuropsychological test, national health insurance claim, and other covariates were included. A total of 1660 patients with AD were included based on Stroop Test results. A total of 1563 patients with AD were included based on the Controlled Oral Word Association Test (COWAT) results. Hip fracture was measured by validated identification criteria using national health insurance claim data. Frontal lobe function was measured by Stroop Test and COWAT at baseline.After adjusting for potential covariates, including cognitive function in other domains (language, verbal and nonverbal memory, and attention), the Cox proportional hazard regression analysis revealed that risk of a hip fracture was decreased with a hazard ratio (HR) of 0.98 per one point of increase in the Stroop Test (adjusted HR = 0.98, 95% confidence interval [CI]: 0.97-1.00) and 0.93 per one point increase in COWAT (adjusted HR = 0.93, 95% CI: 0.88-0.99).The risk of hip fracture in AD patients was associated with baseline frontal lobe function. The result of this research presents evidence of association between frontal lobe function and risk of hip fracture in patients with AD.