Long-term exposure to particulate matter and risk of Alzheimer's disease and vascular dementia in Korea: a national population-based Cohort Study.

BACKGROUND: The prevalence of age-related neurodegenerative diseases has risen in conjunction with an increase in life expectancy. Although there is emerging evidence that air pollution might accelerate or worsen dementia progression, studies on Asian regions remains limited. This study aimed to investigate the relationship between long-term exposure to PM10 and the risk of developing Alzheimer's disease and vascular dementia in the elderly population in South Korea. METHODS: The baseline population was 1.4 million people aged 65 years and above who participated in at least one national health checkup program from the National Health Insurance Service between 2008 and 2009. A nationwide retrospective cohort study was designed, and patients were followed from the date of cohort entry (January 1, 2008) to the date of dementia occurrence, death, moving residence, or the end of the study period (December 31, 2019), whichever came first. Long-term average PM10 exposure variable was constructed from national monitoring data considering time-dependent exposure. Extended Cox proportional hazard models with time-varying exposure were used to estimate hazard ratios (HR) for Alzheimer's disease and vascular dementia. RESULTS: A total of 1,436,361 participants were selected, of whom 167,988 were newly diagnosed with dementia (134,811 with Alzheimer's disease and 12,215 with vascular dementia). The results show that for every 10 µg/m3 increase in PM10, the HR was 0.99 (95% CI 0.98-1.00) for Alzheimer's disease and 1.05 (95% CI 1.02-1.08) for vascular dementia. Stratified analysis according to sex and age group showed that the risk of vascular dementia was higher in men and in those under 75 years of age. CONCLUSION: The results found that long-term PM10 exposure was significantly associated with the risk of developing vascular dementia but not with Alzheimer's disease. These findings suggest that the mechanism behind the PM10-dementia relationship could be linked to vascular damage.

Is Primary Androgen Deprivation Therapy a Suitable Option for Asian Patients With Prostate Cancer Compared With Radical Prostatectomy?

BACKGROUND: We conducted a comparative survival analysis between primary androgen deprivation therapy (PADT) and radical prostatectomy (RP) based on nationwide Korean population data that included all patients with prostate cancer. MATERIALS AND METHODS: This study enrolled 4,538 patients with prostate cancer from the National Health Insurance Service (NHIS) database linked with Korean Central Cancer Registry data who were treated with PADT or RP between January 1, 2007, and December 31, 2014. Kaplan-Meier and multivariate survival analyses stratified by stage (localized and locally advanced) and age (<75 and ≥75 years) were performed using a Cox proportional hazards model to evaluate treatment effects. RESULTS: Among 18,403 patients from the NHIS database diagnosed with prostate cancer during the study period, 4,538 satisfied inclusion criteria and were included in the analyses. Of these, 3,136 and 1,402 patients underwent RP or received PADT, respectively. Risk of death was significantly increased for patients who received PADT compared with those who underwent RP in the propensity score-matched cohort. In subgroup analyses stratified by stage and age, in every subgroup, patients who received PADT had a significantly increased risk of death compared with those who underwent RP. In particular, a much greater risk was observed for patients with locally advanced prostate cancer. CONCLUSIONS: Based on a nationwide survival analysis of nonmetastatic prostate cancer, this study provides valuable clinical implications that favor RP over PDAT for treatment of Asian populations. However, the possibility that survival differences have been overestimated due to not accounting for potential confounding characteristics must be considered.

Exposure to Particulate Matter as a Potential Risk Factor for Attention-Deficit/Hyperactivity Disorder in Korean Children and Adolescents (KNHANES 2008-2018).

Many epidemiological studies have suggested that air pollution adversely affects neurodevelopment in children; however, evidence is still lacking. This study aimed to determine the association between particulate matter (PM) exposure and attention-deficit/hyperactivity disorder (ADHD) in children and adolescents. Data were obtained from the Korean National Health and Nutrition Examination Survey 2008-2018. Outcomes were defined from parental reports of ever doctor-diagnosed ADHD, and ADHD cases were matched to non-cases with 1:10 age-sex matching. Individual exposure levels were assigned according to each study participant's administrative address during the year of diagnosis. Multivariate logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). After age-sex matching at a 1:10 ratio, the final study participants comprised 1,120 children aged 6-19 years old. A unit increase in the PM10 concentration was significantly associated with ADHD (OR, 1.44; 95% CI, 1.02-2.02 per 10 µg/m3). The association with ADHD was stronger at higher quartiles than in the lower quartiles of PM10 exposure; however, it was not statistically significant. Our results suggested that long-term PM10 exposure was associated with increased ADHD in children and adolescents. Children diagnosed with ADHD suffer from a variety of social activity and have a significant economic burden. Therefore, it is considered an important role to find out the effects of environmental risk factors, including air pollution, on children and adolescents. This may also help to increase the body of knowledge in this field and to stimulate further research.

Distribution of Legionella species from environmental water sources of public facilities and genetic diversity of L. pneumophila serogroup 1 in South Korea.

A total of 560 Legionella species were isolated from environmental water sources from public facilities from June to September 2008 throughout South Korea. The distribution of Legionella isolates was investigated according to geographical region, facility type, and sample type. The genetic diversity of 104 isolates of Legionella pneumophila serogroup 1 (sg 1) was analyzed by sequence-based typing (SBT). L. pneumophila was distributed broadly throughout Korea, accounting for 85.0% of the isolates, and L. pneumophila sg 1 predominated in all of the public facilities except for the springs. Legionella anisa and Legionella bozemanii predominated among non-L. pneumophila species (48.1% and 21.0%, respectively). The second most dominant strain differed depending on the facility type: L. anisa was the second most dominant strain in the buildings (10.8%), L. pneumophila sg 5 in public baths (21.6%), L. pneumophila sg 6 in factories (12.0%), and L. pneumophila sg 7 in hospitals (13.1%). In the SBT analysis, 104 L. pneumophila sg 1 isolates were differentiated into 26 sequence types (STs) and categorized into 3 clonal groups (CGs) and 10 singleton STs via the eBURST V3 program. ST1, a potential founder of major CG1, was commonly distributed (48.1%). The dominant ST in hot water was ST-K1 (7, 12, 17, 3, 35, 11, 11), which was designated in this study (36.1%). The second most dominant strain differed depending on the type of facility from which the samples were obtained. The unique allelic profile of ST-K1, obtained from hot water, was not found in the European Working Group for Legionella Infections (EWGLI) SBT database.

Cardiac rehabilitation and 5-year mortality after acute myocardial infarction. Report from 11 tertiary hospitals in Korea (ETHIK Study).

BACKGROUND: The participation rate for cardiac rehabilitation (CR) remains low in some Europe and Asia including Korea. AIM: To investigate effects of CR on prognosis improvements in terms of recurrence, readmission, revascularization, and mortality rates in patients with acute myocardial infarction (AMI) in Korea. DESIGN: A retrospective cohort study. SETTING: Eleven Tertiary Hospitals In Korea (ETHIK Study). POPULATION: Data from a total of 7299 patients between January 2012 and December 2015 were collected, of which data from 7136 patients were linked to insurance claims data. In the final analysis, 6743 patients were included. METHODS: Patients who participated in the CR program while receiving outpatient treatment were classified into CR group. Those who did not participate in CR programs were classified into the non-CR group. RESULTS: Kaplan-Meier survival analyses showed five-year survival rate of 96.9% in the CR group and 93.3% in the non-CR group. The hazard ratio (HR) for total 5-year mortality in the CR group was approximately 0.41 (95% CI: 0.27-0.63) times that of the non-CR group, indicating a reduction in the risk of mortality by approximately 59% in propensity score weighted cohort of 1878 patients. The HR for major adverse cardiac events (MACE) with respect to 5-year mortality, MI recurrence, revascularization, and readmission due to cardiovascular disease in CR group was 0.96 times that of non-CR group (95% CI: 0.83-1.12), without significant difference between the two groups. CONCLUSIONS: In this study, 5-year mortality decreased by 59% in patients with AMI who had participated in CR compared to those who did not. CLINICAL REHABILITATION IMPACT: This finding should be very helpful in emphasizing the need for CR in a country like Korea where CR has not yet been actively implemented.

Nonribosomal peptide synthase is responsible for the biosynthesis of siderophore in Vibrio vulnificus MO6-24/O.

Vibrio vulnificus produces siderophores, lowmolecular- weight iron-chelating compounds, to obtain iron under conditions of iron deprivation. To identify genes associated with the biosynthesis of siderophore in V. vulnificus MO6-24/ O, we screened clones with mini-Tn5 random insertions for those showing decreased production of siderophore. Among 6,000 clones screened, nine such clones were selected. These clones contain the transposon inserted in VV2_0830 (GenBank accession number) that is a homolog of a nonribosomal peptide synthetase (NRPS). There is an another NRPS module, VV2_0831, 49-bp upstream to VV2_0830. We named these two genes vvs (Vibrio vulnificus siderophore synthetase) A and B, respectively. Mutation of either vvsA or vvsB showed a decreased production of siderophore. The expression of an NRPS-lux fusion was negatively modulated by the presence of iron, and the regulation was dependent on Fur (ferric uptake regulator). However, the expression of the NRPS genes was still not fully derepressed in the iron-rich condition, even in fur-null mutant cells, suggesting that some other unknown factors are involved in the regulation of the genes. We also demonstrated that the NRPS genes are important for virulence of the pathogen in a mice model.

Prevalence of thyroid nodules and their associated clinical parameters: a large-scale, multicenter-based health checkup study.

Background/Aims: We evaluated the prevalence and characteristics of thyroid nodules detected by thyroid ultrasound (US) at health checkups and the associated clinical parameters. METHODS: A total of 72,319 subjects who underwent thyroid US at three health checkup centers in Korea from January 2004 to December 2010 were included in this study. The correlations between the presence of thyroid nodules and other clinical parameters were analyzed. RESULTS: The prevalence of thyroid nodules and cysts was 34.2% (n = 24,757). Thyroid nodules were more prevalent in women and older age groups. Among the subjects with thyroid nodules with size information (n = 24,686), 18,833 (76.3%) had nodules measuring ≤ 1.0 cm. Women and older age groups showed higher proportion of larger nodules. Percentage of women, age, body mass index (BMI), waist circumference, body fat composition, blood pressure, and the level of fasting glucose, total cholesterol, and low density lipoprotein cholesterol were higher in the subjects with thyroid nodules compared to those without nodules. The prevalence of metabolic syndrome and overt/subclinical thyrotoxic state was higher in the subjects with thyroid nodules. In the multivariable logistic regression analysis, women, age, BMI, metabolic syndrome, and thyrotoxicosis were independently associated with the presence of thyroid nodules. Conclusions: The high prevalence of thyroid nodules in people who underwent thyroid US at a health checkup suggests that increased detection of thyroid nodules resulted in an increased prevalence in the general population. However, metabolic disturbances may also have contributed to the increase in thyroid nodule prevalence in Korea.

Cost-effectiveness of coronary CT angiography in patients with chest pain: Comparison with myocardial single photon emission tomography.

BACKGROUND: Coronary CT angiography (CCTA) has been proven accurate and is incorporated in clinical recommendations for coronary artery disease (CAD) diagnosis workup, but cost-effectiveness data, especially in comparison to other methods such as myocardial single photon emission CT (SPECT) are insufficient. OBJECTIVE: To compare the cost-effectiveness of CCTA and myocardial SPECT in a real-world setting. METHODS: We performed a retrospective cohort study on consecutive patients with suspected CAD and a pretest probability between 10% and 90%. Test accuracy was compared by correcting referral bias to coronary angiography depending on noninvasive test results based on the Bayes' theorem and also by incorporating 1-year follow-up results. Cost-effectiveness was analyzed using test accuracy and quality-adjusted life year (QALY). The model using diagnostic accuracy used the number of patients accurately diagnosed among 1000 persons as the effect and contained only expenses for diagnostic testing as the cost. In the model using QALY, a decision tree was developed, and the time horizon was 1 year. RESULTS: CCTA was performed in 635 patients and SPECT in 997 patients. An accurate diagnosis per 1000 patients was achieved in 725 patients by CCTA vs 661 patients by SPECT. In the model using diagnostic accuracy, CCTA was more effective and less expensive than SPECT ($725.38 for CCTA vs $661.46 for SPECT). In the model using QALY, CCTA was generally more effective in terms of life quality (0.00221 QALY) and cost ($513) than SPECT. However, cost utility varied among subgroups, with SPECT outperforming CCTA in patients with a pretest probability of 30% to 60% (0.01890 QALY; $113). CONCLUSION: These results suggest that CCTA may be more cost-effective than myocardial SPECT.

Results of colorectal cancer screening of the national cancer screening program in Korea, 2008.

PURPOSE: This study aims to investigate the current situation of national colorectal cancer screening by analyzing participation rates, positive rates of screening methods and screening rate of secondary screening tests in colorectal screening of the national cancer screening program in 2008. MATERIALS AND METHODS: With database about target population and screened individuals of the national cancer screening program, the results of target population and participants of colorectal cancer screening in 2008 were analyzed. Among adults aged over 50 years of medical aid and beneficiaries of national health insurance paying lower 50% premiums in the total subscribers, 4,640,365 were target population of colorectal cancer screening and the data of 984,915 undergoing fecal occult blood test (FOBT) as a primary screening were analyzed. RESULTS: The colorectal cancer screening rate was 21.2% and the rates of national health insurance subscribers, females and the elderly aged 60-64 years were higher than those of others. The recipients with a positive result in FOBT recorded approximately 7.5%. Medical aid beneficiaries (7.9%), males (8.8%) and seniors aged over 75 years (9.1%) showed higher positive rates than the average one. Out of the FOBT positive recipients, 43.0% took a secondary screening and the rate undergoing colonoscopy (31.4%) was higher than that of doing double-contrast barium enema test (11.6%). CONCLUSION: Colorectal cancer screening rate of medical aid beneficiaries and people paying lower 50% premiums among national health insurance subscribers, was different according to demographic characters (gender, age and types of health insurance). This finding meant that screening for the vulnerable needed to be encouraged by considering socio-demographic characters. Additionally, more efforts were necessary to increase the secondary screening rate of people with a positive result in primary one.

Trends of mammography use in a national breast cancer screening program, 2004-2008.

PURPOSE: Korea started breast cancer screening as part of the National Cancer Screening Program (NCSP) in 1999. In order to identify under-served groups, we investigated mammography uptake in the National Breast Cancer Screening Program. MATERIALS AND METHODS: The study population was participants in the National Breast Cancer Screening Program from 2004 to 2008. We analyzed participation rates by insurance type, age group, and area of residence. RESULTS: Total participation rates for breast cancer screening increased from 18.2% in 2004 to 35.0% in 2008. The participation rate in the group aged 60 to 69 years showed the greatest increase, 21.3%, among the four age groups. Although the screening rate increased continuously, the participation rate of the Medical Aid Program (MAP) group was low compared to the National Health Insurance (NHI) group. Moreover, the increasing trend of mammography uptake in the MAP group was much lower than that of the NHI group. CONCLUSION: The participation rate for breast cancer screening in the NCSP in Korea has increased. However, the participation rate in mammography among MAP recipients is still lower than that of NHI beneficiaries. To increase mammography uptake, it is important to make it available to everyone by ensuring inclusion of all population subgroups.