Airflow analysis of Pyeongtaek St Mary's Hospital during hospitalization of the first Middle East respiratory syndrome patient in Korea

Middle East respiratory syndrome (MERS) is known to be transmitted through close contact. However, epidemiological surveys of MERS in Korea indicated that some secondary patients were infected without close contact. Therefore, the possibility of other transmission routes must be identified. In this study, the possibility of MERS spreading through airflow was investigated on the eighth floor of Pyeongtaek St Mary's Hospital. Computational fluid dynamics was used to analyse the indoor airflow and passive tracer diffusion during the index patient's stay. Six cases were simulated for different outdoor wind directions and indoor mechanical ventilation operations. When a passive tracer was released in ward 8104, where the index patient was hospitalized, the passive tracer spread through the indoor airflow, which was created by the outdoor airflow. Ward 8109, which had the largest number of infected cases and was far distant from ward 8104, showed passive tracer concentration in all cases. This result indicates that MERS may have spread through airflow. The study results do not imply that the infection pathway of MERS is airborne. However, the results show the possibility of MERS spreading through airflow in specific environments such as poor ventilation environments.

Association of Dietary Potassium Intake with the Development of Chronic Kidney Disease and Renal Function in Patients with Mildly Decreased Kidney Function: The Korean Multi-Rural Communities Cohort Study

Background

Dietary potassium has negative outcomes in patients with mildly impaired kidney function, while having positive outcomes in patients with hypertension. The association of dietary potassium intake with chronic kidney disease (CKD) development, with presence of hypertension, was studied in the Korean rural population with mildly impaired kidney function.

Material/Methods

From 3 rural areas of Korea, 5064 participants age ≥40 with CKD stage 2 at baseline were recruited. Patients were classified according to the quartile of dietary potassium intake. Newly developed CKD, defined as estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m² at the time of follow-up, and eGFR decline, defined as eGFR decrease >15% at follow-up, were studied. The effect of dietary potassium on CKD development and eGFR decline were studied by Cox proportional hazard models. The association of potassium with blood pressures and C-reactive protein was also studied to examine the underlying mechanisms.

Results

Compared to 8.6% in normotensives, 15.7% of hypertensives developed CKD. The hazard ratio (HR) (95% confidence interval) of CKD was lower in high potassium diet only in hypertensives, with 0.60 (0.37–0.99) in the highest quartile. The eGFR decline was also lower in patients with higher potassium diet, with 0.70 (0.50–0.98) in Q3 and 0.54 (0.34–0.85) in Q4. Potassium intake has also been shown to decrease high diastolic blood pressure development (>90 mmHg) in hypertensives at 0.45 (0.25–0.83).

Conclusions

Dietary potassium was associated with lower risk of CKD development and eGFR decline, and this association was observed only in hypertensives.

Health Indicators Related to Disease, Death, and Reproduction

One of the primary goals of epidemiology is to quantify various aspects of a population’s health, illness, and death status and the determinants (or risk factors) thereof by calculating health indicators that measure the magnitudes of various conditions. There has been some confusion regarding health indicators, with discrepancies in usage among organizations such as the World Health Organization the, Centers for Disease Control and Prevention (CDC), and the CDC of other countries, and the usage of the relevant terminology may vary across papers. Therefore, in this review, we would like to propose appropriate terminological definitions for health indicators based on the most commonly used meanings and/or the terms used by official agencies, in order to bring clarity to this area of confusion. We have used appropriate examples to make each health indicator easy for the reader to understand. We have included practical exercises for some health indicators to help readers understand the underlying concepts.

Comparison of Characteristics and Survival between Prospective and Retrospective Korea Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome Cohort Studies

By comparing the data of prospectively and retrospectively enrolled cohorts, we evaluated whether the prospective cohort represented all patients in the retrospective cohort. The prospectively enrolled subjects were older and had lower CD4+ T cell counts, higher viral load. In addition, the initial antiretroviral treatment regimen of the prospective cohort consisted of less integrase strand transfer inhibitor-containing regimens. The 20-year survival rate was 51.8% in the prospective cohort and 84.6% in the retrospective cohort, respectively (P = 0.844). This study suggests the prospective cohort study may not represent all patients.

Airflow as a Possible Transmission Route of Middle East Respiratory Syndrome at an Initial Outbreak Hospital in Korea

In this study, the results of an airflow investigation conducted on 7 June 2015 as part of a series of epidemiologic investigations at Pyeongtaek St. Mary's Hospital, South Korea, were investigated. The study involved 38 individuals who were infected directly and indirectly with Middle East Respiratory Syndrome (MERS), by a super-spreader patient. Tracer gas experiments conducted on the eighth floor, where the initial patient was hospitalized, confirmed that the tracer gas spread to adjacent patient rooms and rooms across corridors. In particular, the experiment with an external wind direction and speed similar to those during the hospitalization of the initial patient revealed that the air change rate was 17⁻20 air changes per hour (ACH), with air introduced through the window in the room of the infected patient (room 8104). The tracer gas concentration of room 8110, which was the farthest room, was 7.56% of room 8104, indicating that a high concentration of gas has spread from room 8104 to rooms across the corridor. In contrast, the tracer gas was barely detected in a maternity ward to the south of room 8104, where there was no secondary infected patient. Moreover, MERS is known to spread mainly by droplets through close contact, but long-distance dispersion is probable in certain environments, such as that of a super-spreader patient hospitalized in a room without ventilation, hospitals with a central corridor type, and indoor airflow dispersion due to external wind.

Habitual consumption of soy protein and isoflavones and risk of metabolic syndrome in adults ≥ 40 years old: a prospective analysis of the Korean Multi-Rural Communities Cohort Study (MRCohort)

PURPOSE

Although considerable attention has been paid to the potential benefits of soy protein and isoflavones for preventing metabolic syndrome (MetS) and its components, findings linking habitual consumption of these factors to MetS are limited. This study aimed to evaluate the association of MetS incidence with habitual intake of soy protein/isoflavones among Korean men and women aged ≥ 40 years old who did not have MetS at baseline (n = 5509; 2204 men and 3305 women).

METHODS

Dietary intake of soy protein/isoflavones at baseline and average consumption during follow-up were used.

RESULTS

A significant inverse association between dietary intake and incidence of MetS was found in women (incidence rate ratios, IRR = 0.60, 95% CI = 0.46-0.78, P for trend = 0.0094 for the highest quintile of average soy protein intake compared with the lowest quintile; IRR = 0.57, 95% CI = 0.44-0.74, P for trend = 0.0048 for the highest quintile of average isoflavones intake compared with the lowest quintile). A tendency towards an inverse association was also found in men, although it was not significant for the highest quintile (IRR = 0.80, 95% CI = 0.58-1.11, P for trend = 0.9759, comparing the lowest to the highest quintile of average soy protein intake; IRR = 0.73, 95% CI = 0.53-1.01, P for trend = 0.8956, comparing the lowest to the highest quintile of average isoflavones intake). In terms of individual abnormalities, a significant inverse association was found between soy protein and isoflavones and the incidence of low-high-density lipoprotein cholesterol in both men and women. Abdominal obesity and elevated blood pressure were inversely related to soy protein/isoflavones only in women, and an inverse association of elevated triglyceride appeared only in men.

CONCLUSION

Our findings suggest that habitual intake of soy protein and isoflavones is inversely associated with the risk of MetS and its components. There is likely to be a reverse J-shaped association of average intake with MetS.

Effect of Uric Acid on the Development of Chronic Kidney Disease: The Korean Multi-Rural Communities Cohort Study

Objectives

Several studies have investigated the effects of serum uric acid (SUA) levels on chronic kidney disease (CKD), with discrepant results. The effect of SUA levels on CKD development was studied in the Korean rural population.

Methods

A total of 9695 participants aged ≥40 years were recruited from 3 rural communities in Korea between 2005 and 2009. Of those participants, 5577 who participated in the follow-up and did not have cerebrovascular disease, myocardial infarction, cancer, or CKD at baseline were studied. The participants, of whom 2133 were men and 3444 were women, were grouped into 5 categories according to their quintile of SUA levels. An estimated glomerular filtration rate of <60 mL/min/1.73 m² at the time of follow-up was considered to indicate newly developed CKD. The effects of SUA levels on CKD development after adjusting for potential confounders were assessed using Cox proportional hazard models.

Results

Among the 5577 participants, 9.4 and 11.0% of men and women developed CKD. The hazard ratio (HR) of CKD was higher in the highest quintile of SUA levels than in the third quintile in men (adjusted HR, 1.60; 95% confidence interval [CI], 1.02 to 2.51) and women (adjusted HR, 1.56; 95% CI, 1.14 to 2.15). Furthermore, CKD development was also more common in the lowest quintile of SUA levels than in the third quintile in men (adjusted HR, 1.83; 95% CI, 1.15 to 2.90). The effect of SUA was consistent in younger, obese, and hypertensive men.

Conclusions

Both high and low SUA levels were risk factors for CKD development in rural Korean men, while only high levels were a risk factor in their women counterparts.

The coverage rates for influenza vaccination and related factors in Korean adults aged 50 and older with chronic disease: based on 2016 Community Health Survey data

OBJECTIVES

This study aims to identify the coverage rates for influenza vaccination and related factors depending on chronic disease in Korean adults aged 50 and older.

METHODS

The 2016 Korea Community Health Survey was used for analysis. Chi-square test was performed to investigate the coverage rates for influenza vaccination depending on chronic disease, and a multiple logistic regression analysis was used to identify the factors associated with influenza vaccination, by chronic disease.

RESULTS

In men with ≥1 chronic disease, 39.8% of 50-64 years of age, and 86.8% of elderly (over 65 years of age) received influenza vaccination. In women with ≥1 chronic disease, 58.7% of 50-64 years of age, and 89.9% of elderly (over 65 years of age) received influenza vaccination (p<0.001). The chronic diseases associated with influenza vaccination were hypertension (odds ratio [OR], 1.27; 95% confidence interval [CI], 1.19 to 1.37), diabetes (OR, 1.41; 95% CI, 1.28 to 1.55) in men aged 50-64, hypertension (OR, 1.34; 95% CI, 1.20 to 1.49), diabetes (OR, 1.17; 95% CI, 1.02 to 1.33), chronic cardiovascular disease (OR, 1.31; 95% CI, 1.07 to 1.60) in elderly (over 65 years of age). In women aged 50-64, hypertension (OR, 1.39; 95% CI, 1.30 to 1.49), diabetes (OR, 1.51; 95% CI, 1.35 to 1.68), chronic cardiovascular disease (OR, 1.31; 95% CI, 1.05 to 1.64), and hypertension (OR, 1.55; 95% CI, 1.40 to 1.71), diabetes (OR, 1.27; 95% CI, 1.12 to 1.43) in elderly (over 65 years of age).

CONCLUSIONS

Populations in aged 50-64 are recommendation subject for vaccination or classified as high-risk group in case with chronic disease. Though subject over 60 years old is age close to the elderly, the coverage rates for vaccination was low. It is necessary to devise strategies to raise the coverage rates for vaccination.

Association between objectively measured built environments and adult physical activity in Gyeonggi province, Korea

OBJECTIVES

In the present study, the association between objectively measured built environments and physical activity (PA) was examined.

METHODS

Data were obtained from the Korean Community Health Survey (KCHS). A total of 82,419 individuals living in 546 neighborhoods of Gyeonggi province were analyzed. Built environments were measured by geographic information systems (GIS) using Korean government databases. PA was assessed using the IPAQ-short form. Multilevel logistic regression was performed.

RESULTS

Living in a community with a short distance to parks was associated with a 42% increased odds of PA; living in a community with low population density was associated with a 21% decreased odds of PA. However, most variations in PA were attributed to individual factors. Additionally, gender-specific correlates associated with PA were observed.

CONCLUSIONS

Although the associations of individual factors with PA were stronger than of community factors, notably, built environments influenced most people in a community. Therefore, along with health education and service, policy makers and planners should consider more parks in less populated areas to create a supportive environment for PA.

Korea HIV/AIDS Cohort Study: study design and baseline characteristics

The number of persons infected by HIV/AIDS has consistently increased in Korea since the first case of HIV/AIDS infection in 1985 and reached 15,208 by 2016. About 1,100 new patients with HIV/ AIDS infections have emerged every year since 2013. In Korea, the Korea HIV/AIDS Cohort Study was established for the evidenced-based prevention, treatment, and effective management of patients infected with human immunodeficiency virus (HIV) in December 2006. This study monitored 1,438 patients, who accounted for about 10% of all patients with HIV/AIDS in Korea, for 10 years with the following aims: (1) to develop an administrative system for the establishment of a HIV/AIDS cohort-based study; (2) to standardize methodologies and the case report forms; and (3) to standardize multi-cohort data and develop a data cleaning method. This study aims to monitor at least 1,000 patients (excluding those for whom investigation had been completed) per year (estimated number of patients who can be monitored by January 2018: 939). By December 2016, the sex distribution was 93.3% for men, and 6.7% for women (gender ratio, 13.9:1.0), and 98.9% of all participants were Korean. More than 50.0% of the participants were confirmed as HIV positive after 2006. This study reports competitive, long-term research that aimed to develop policies for the prevention of chronic infectious diseases for patients with HIV. The data collected over the last decade will be used to develop indices for HIV treatment and health promotion.

High sodium intake and sodium to potassium ratio may be linked to subsequent increase in vascular damage in adults aged 40 years and older: the Korean multi-rural communities cohort (MRCohort)

PURPOSE

Subclinical vascular damage is a chronic intermediate process in cardiovascular disease (CVD) and high sodium (Na) has been regarded as an adverse factor in subclinical vascular health; however, the longitudinal relationship between Na intake and subclinical vascular damage has not been studied. We aimed to evaluate the longitudinal relationship of dietary Na intake and sodium to potassium ratio (Na:K) with brachial-ankle pulse wave velocity (baPWV) and carotid intima media thickness (cIMT) in healthy adults aged 40 years and older in Korea.

METHODS

The present study was based on participants (n = 2145 for baPWV analysis and n = 2494 for cIMT analysis) who visited three times during 2005-2013 (median 5.3 years of follow-up). We used both dietary Na intake and Na:K at baseline and its average (baseline, 2nd, 3rd), which was obtained from food frequency questionnaire (FFQ) as exposure at every visit. baPWV and cIMT levels at the third visit and change from baseline to the third visit were used to represent the level of subclinical vascular damage.

RESULTS

After adjustment for potential confounders, significant positive relationships between dietary Na intake and both baPWV_3rd and cIMT_3rd were observed (baPWV: p for trend ≤ 0.0001 for Na_average; cIMT: p for trend = 0.013 for Na_average). Compared with Na:Ks less than 1.0, the levels of both baPWV and cIMT were higher for participants with Na:Ks over 1.0 (baPWV: p for trend = 0.0002 for Na:K_average; cIMT: p for trend = 0.005 for Na:K_average). Similar significant trends were shown in relationships between dietary Na intake and Na:K and changes in baPWV and cIMT levels.

CONCLUSIONS

In conclusion, dietary Na intake and Na:K may be positively linked to subsequent baPWV and cIMT levels in adults aged 40 years and older in Korea. Our findings may provide informative evidence on subclinical vascular damage, particularly for populations with relatively high dietary Na intake and low dietary K intake.

Asymptomatic Middle East Respiratory Syndrome coronavirus infection using a serologic survey in Korea

OBJECTIVES

The rates of asymptomatic infection with Middle East Respiratory Syndrome (MERS) coronavirus vary. A serologic study was conducted to determine the asymptomatic MERS infection rate in healthcare workers and non-healthcare workers by exposure status.

METHODS

Study participants were selected from contacts of MERS patients based on a priority system in 4 regions strongly affected by the 2015 MERS outbreak. A sero-epidemiological survey was performed in 1,610 contacts (average duration from exposure to test, 4.8 months), and the collected sera were tested using an enzyme-linked immunespecific assay (ELISA), immunofluorescence assay (IFA), and plaque reduction neutralization antibody test (PRNT). Among the 1,610 contacts, there were 7 ELISA-positive cases, of which 1 exhibited positive IFA and PRNT results.

RESULTS

The asymptomatic infection rate was 0.060% (95% confidence interval, 0.002 to 0.346). The asymptomatic MERS case was a patient who had been hospitalized with patient zero on the same floor of the hospital at the same time. The case was quarantined at home for 2 weeks after discharge, and had underlying diseases, including hypertension, angina, and degenerative arthritis.

CONCLUSIONS

The asymptomatic infection was acquired via healthcare-associated transmission. Thus, it is necessary to extend serologic studies to include inpatient contacts who have no symptoms.

Associations of serum levels of vitamins A, C, and E with the risk of cognitive impairment among elderly Koreans

BACKGROUND/OBJECTIVES

Korea is quickly becoming an aged society. Dementia is also becoming a vital public health problem in Korea. Cognitive impairment as a pre-stage of dementia shares most risk factors for dementia. The aim of the present study was to determine associations of serum levels of vitamins A, C, and E with the risk of cognitive impairment among elderly Koreans.

SUBJECTS/METHODS

In this cross-sectional study, a total of 230 participants aged 60-79 years from Yangpyeong cohort were included. Cognitive function was assessed by the Korean version of the Mini-Mental State Examination for Dementia Screening. The logistic multivariable regression model was applied to determine the effect of serum vitamins A, C, and E on the risk of cognitive impairment.

RESULTS

There was no significant association between the risk of cognitive impairment and serum levels of vitamin A and vitamin C. There was a significant odd ratio when the second tertile group of beta-gamma tocopherol level was compared to the first tertile group [odds ratio (OR) = 0.37, 95% confidence interval (CI) = 0.14-0.98, P for trend = 0.051]. In subgroup analyses, there were significant negative associations between beta-gamma tocopherol level and the risk of cognitive impairment in men (OR = 0.17, 95% CI = 0.03-0.87, P for trend = 0.028), non-drinkers or former drinkers (OR = 0.13, 95% CI = 0.02-0.66, P for trend = 0.025), and non-smokers or former smokers (OR = 0.27, 95% CI = 0.09-0.82, P for trend = 0.017).

CONCLUSION

Serum beta-gamma tocopherol levels tended to be inversely associated with the risk of cognitive impairment. Further prospective large-scaled studies are needed to examine this association.

Complications and Socioeconomic Costs Associated With Falls in the Elderly Population

Objective

To explore the incidence, characteristics, complications and socioeconomic impacts associated with falls in community-dwelling elderly.

Methods

From September 1, 2015 to October 12, 2015, a questionnaire-based survey was conducted involving a total of 2,012 elderly who lived in Guro-gu (Seoul), Yeongdeungpo-gu (Seoul), Yangpyeong-gu (Gyeonggi-do), Dalseong-gu (Daegu), and Jung-gu (Daegu). The subjects were interviewed using a structured questionnaire to obtain demographic characteristics and comprehensive falling histories. The socioeconomic cost related to falls was estimated using the statistical data provided by the Health Insurance Review and Assessment Service.

Results

Falls were recorded in 666 out of the 2,012 subjects (33.1%) during the past year. Frequent falls occurred during December, in the afternoons, when the floor was slippery. The most common injuries included the low back and the most common injury type was sprain. The total direct costs related to falls involving the 2,012 subjects were 303,061,019 KRW (Korean won). The average medical cost related to falls in the 2,012 subjects was 150,627 KRW and the average medical cost of 666 subjects who experienced falls was 455,047 KRW. Estimates of the total population over the age of 60 years showed that the annual direct costs associated with falls in Korea over the age of 60 years were about 1.378 trillion KRW.

Conclusion

This study was conducted to explore the incidence, characteristics, complications, and socioeconomic impacts of falls in community-dwelling elderly. This study is expected to be used as a source of basic data for the establishment of medical policy for the elderly and the development of a fall prevention program for the elderly in Korea.

Cognitive impairment is associated with elevated serum homocysteine levels among older adults

PURPOSE

The aim of this study was to examine the associations between the risk of cognitive impairment and the serum levels of folate, vitamin B₁₂, and homocysteine (Hcy).

METHODS

Subjects were persons aged 60-79 years who participated in the Yangpyeong Cohort study between 2011 and 2012. Cognitive impairment and normal subjects consisted of 100 pairs of old adults matched by age, sex, and education levels. Cognitive function was evaluated with the Korean version of the Mini-Mental State Examination for Dementia Screening (MMSE-DS). Pearson's partial correlation coefficients and conditional multiple logistic regression analysis were applied to determine the associations between cognitive function and the serum levels of folate, vitamin B₁₂, and Hcy.

RESULTS

Compared with the matched normal group, the cognitive impairment group had higher proportions of folate deficiency (< 3 ng/mL) and hyperhomocysteinemia (≥ 15 µmol/L). Serum Hcy concentrations were inversely associated with serum folate (r = - 0.234, p = 0.001) and MMSE-DS score (r = - 0.150, p = 0.037) after adjusting for age, sex, and education. The high Hcy group showed a higher prevalence of cognitive impairment (4th vs. 1st quartile, OR 3.30, 95% CI 1.12-9.72, p for trend = 0.014) after adjusting for exercise.

CONCLUSIONS

The present findings suggest a putative protective role of high serum folate and normal Hcy against cognitive impairment among older adults.

Acetylcholine precursor, citicoline (cytidine 5'-diphosphocholine), reduces hypoglycaemia-induced neuronal death in rats

Citicoline (cytidine 5'-diphosphocholine) is an important precursor for the synthesis of neuronal plasma membrane phospholipids, mainly phosphatidylcholine. The administration of citicoline serves as a choline donor for the synthesis of acetylcholine. Citicoline has been shown to reduce the neuronal injury in animal models with cerebral ischaemia and in clinical trials of stroke patients. Citicoline is currently being investigated in a multicentre clinical trial. However, citicoline has not yet been examined the context of hypoglycaemia-induced neuronal death. To clarify the therapeutic impact of citicoline in hypoglycaemia-induced neuronal death, we used a rat model with insulin-induced hypoglycaemia. Acute hypoglycaemia was induced by i.p. injection of regular insulin (10 U kg^-1 ) after overnight fasting, after which iso-electricity was maintained for 30 minutes. Citicoline injections (500 mg/kg, i.p.) were started immediately after glucose reperfusion. We found that post-treatment of citicoline resulted in significantly reduced neuronal death, oxidative injury and microglial activation in the hippocampus compared to vehicle-treated control groups at 7 days after induced hypoglycaemia. Citicoline administration after hypoglycaemia decreased immunoglobulin leakage via blood-brain barrier disruption in the hippocampus compared to the vehicle group. Citicoline increased choline acetyltransferase expression for phosphatidylcholine synthesis after hypoglycaemia. Altogether, the present findings suggest that neuronal membrane stabilisation by citicoline administration can save neurones from the degeneration process after hypoglycaemia, as seen in several studies of ischaemia. Therefore, the results suggest that citicoline may have therapeutic potential to reduce hypoglycaemia-induced neuronal death.

Dietary total, animal, vegetable calcium and type 2 diabetes incidence among Korean adults: The Korean Multi-Rural Communities Cohort (MRCohort)

BACKGROUND AND AIMS

Although a possible mechanism for developing type 2 diabetes in relation to calcium intake has been suggested, there is currently little epidemiological evidence on the association between dietary calcium and type 2 diabetes (T2D). This study aimed to evaluate the prospective association between dietary calcium and T2D incidence among adults 40 years of age or over, from the Multi-rural Communities Cohort (MRCohort), South Korea.

METHODS AND RESULTS

In total, 8313 participants (3033 men and 5280 women) who did not have diabetes at baseline were recruited between 2005 and 2013. The incidence rate ratio (IRR) was estimated using a modified Poisson regression model with a robust error estimator. During follow-up (31,570 person-years), 322 T2D cases were newly diagnosed. Dietary calcium (total and vegetable calcium) were inversely associated with the risk of T2D incidence among women (IRR = 0.61, 95% CI = 0.43-0.86, P for trend = 0.007 in third tertile of baseline total calcium intake comparing to the first tertile; IRR = 0.57, 95% CI = 0.39-0.84, P for trend = 0.006 for baseline vegetable calcium intake), not for men. The tendency of those inverse associations remained in both the normal fasting blood glucose group and the impaired fasting blood glucose group and were independent of obesity, smoking, and magnesium intake.

CONCLUSIONS

Total and vegetable calcium may be inversely associated with T2D incidence among women, regardless of impaired fasting blood glucose group or normal group. The associations may be potentially dose-responsive. Moderate dietary calcium may be related to lower risk of T2D incidence comparing to low intake group among women.

High reproduction number of Middle East respiratory syndrome coronavirus in nosocomial outbreaks: mathematical modelling in Saudi Arabia and South Korea

Background

Effective countermeasures against emerging infectious diseases require an understanding of transmission rate and basic reproduction number (R₀). R₀ for severe acute respiratory syndrome is generally considered to be >1, whereas that for Middle East respiratory syndrome (MERS) is considered to be <1. However, this does not explain the large-scale outbreaks of MERS that occurred in Kingdom of Saudi Arabia (KSA) and South Korean hospitals.

Aim: To estimate R₀ in nosocomial outbreaks of MERS.

Methods

R₀ was estimated using the incidence decay with an exponential adjustment model. The KSA and Korean outbreaks were compared using a line listing of MERS cases compiled using publicly available sources. Serial intervals to estimate R₀ were assumed to be six to eight days. Study parameters [R₀ and countermeasures (d)] were estimated by fitting a model to the cumulative incidence epidemic curves using Matlab.

Findings

The estimated R₀ in Korea was 3.9 in the best-fit model, with a serial interval of six days. The first outbreak cluster in a hospital in Pyeongtaek had an R₀ of 4.04, and the largest outbreak cluster in a hospital in Samsung had an R₀ of 5.0. Assuming a six-day serial interval, the KSA outbreaks in Jeddah and Riyadh had R₀ values of 3.9 and 1.9, respectively.

Conclusion

R₀ for the nosocomial MERS outbreaks in KSA and South Korea was estimated to be in the range of 2–5, which is significantly higher than the previous estimate of <1. Therefore, more comprehensive countermeasures are needed to address these infections.

The long-term relationship between dietary pantothenic acid (vitamin B5) intake and C-reactive protein concentration in adults aged 40 years and older

BACKGROUND AND AIMS

Low-grade inflammation, represented by minor C-reactive protein (CRP) elevation, has a critical role in the early stages of atherosclerosis, and pantothenic acid (PA) may have an antioxidant effect in inflammatory process. However, the long-term relationship between PA intake and CRP has not yet been studied. The objective of the present study was to evaluate the long-term relationship of PA intake to CRP concentration in healthy adults aged 40 years or older living in a rural area of South Korea.

METHODS AND RESULTS

A total of 908 subjects (349 men, 559 women) with repeated data on dietary PA intake and CRP concentration were included in the final analysis. To represent the long-term effect of PA intake, both PA intake at the baseline and average PA intake were used as the exposure, and CRP concentration at the third visit and its change from the baseline to the third visit were used as the outcome. After adjustment for potential confounders, a significant inverse relationship between PA intake and CRP concentration at the third visit was observed (P for trend = 0.001, β = -0.07 (P-value = 0.001) for PA _baseline; P for trend = <0.0001, β = -0.11 (P-value = 0.0004) for PA _{average (baseline, 2nd, 3rd)}). Higher PA intake was significantly related to lower or attenuated increase in CRP concentration (P for trend = 0.002, β = -0.24 (P-value = 0.002) for PA _baseline; P for trend = 0.001, β = -0.35 (P-value = 0.001) for PA _{average (baseline, 2nd, 3rd)}).

CONCLUSIONS

In conclusion, dietary PA intake was inversely related to subsequent CRP concentration in both men and women aged 40 years or older in South Korea.

Metabolic Complications among Korean Patients with HIV Infection: The Korea HIV/AIDS Cohort Study

Currently, metabolic complications are the most common problem among human immunodeficiency virus (HIV)-infected patients, with a high incidence. However, there have been very few studies regarding metabolic abnormalities published in Asia, especially in Korea. This cross-sectional study was performed to investigate the prevalence of and risk factors for metabolic abnormalities in 1,096 HIV-infected patients of the Korea HIV/AIDS cohort study enrolled from 19 hospitals between 2006 and 2013. Data at entry to cohort were analyzed. As a result, the median age of the 1,096 enrolled subjects was 46 years, and most patients were men (92.8%). The metabolic profiles of the patients were as follows: median weight was 63.8 kg, median body mass index (BMI) was 22.2 kg/m², and 16.4% of the patients had a BMI over 25 kg/m². A total of 5.5% of the patients had abdominal obesity (waist/hip ratio ≥ 1 in men, ≥ 0.85 in women). Increased levels of fasting glucose, total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides were present in 10.4%, 6.0%, 5.5%, and 32.1% of the patients. Decreased high-density lipoprotein (HDL) cholesterol levels were observed in 44.2% of the patients. High systolic blood pressure was present in 14.3% of the patients. In multivariate analysis, high BMI and the use of protease inhibitors (PIs) were risk factors for dyslipidemia in HIV-infected patients. In conclusion, proper diagnosis and management should be offered for the prevalent metabolic complications of Korean HIV-infected patients. Further studies on risk factors for metabolic complications are needed.

The association of lower urinary tract symptoms with incidental falls and fear of falling in later life: The Community Health Survey

AIM

To evaluate the association between lower urinary tract symptoms (LUTS) and incidental falls and fear of falling.

METHODS

We used data obtained from the 2011 Korean Community Health Survey (KCHS) conducted between August and October 2011 in South Korea. The survey was carried out to estimate patterns of disease prevalence and morbidity in men >40 years old. The trained interviewers performed face-to-face sociodemographic questionnaires using computer-assisted personal interviewing (CAPI) software, the International Prostate Symptom Score (IPSS), the Quality of Life score (EQ-5D), and a questionnaire about past falls and fear of falling.

RESULTS

Data from 67 457 men were collected and analyzed. The subjects who had previously experienced a fall had slightly higher scores for IPSS, severity of LUTS, voiding LUTS, and storage LUTS than subjects with no prior fall history. A multivariate model of the relationship between falls and LUTS severity indicated that the relationship between the IPSS components and fall history was significant (mild, moderate, severe: OR = 1.00, 2.53, 3.91, respectively, P < 0.0001). A multivariate model of fear of falling and LUTS also showed a significant relationship between severity, voiding, and storage symptoms (severe IPSS: OR = 2.411, 95%CI: 2.2-2.642, P < 0.001; voiding symptoms: OR = 1.766, 95%CI: 1.681-1.856, P < 0.001; storage symptoms: OR = 1.705, 95%CI: 1.625-1.789, P < 0.001).

CONCLUSION

This study emphasizes the relationship between LUTS and falling. Furthermore, increased LUTS severity led to a higher risk of incidental falls. A high correlation between fear of falling and LUTS was also observed in this study.

Trend of CD4+ Cell Counts at Diagnosis and Initiation of Highly Active Antiretroviral Therapy (HAART): Korea HIV/AIDS Cohort Study, 1992-2015

Background

CD4+ cell counts reflect immunologic status of human immunodeficiency virus (HIV) patients. Recommended CD4+ cell counts for the initiation of highly active antiretroviral therapy (HAART) has increased over the past several years in various HIV treatment guidelines. We investigated the trend of CD4+ cell counts at diagnosis and treatment start using data from the Korea HIV/acquired immune deficiency syndrome (AIDS) Cohort Study.

Materials and Methods

The Korea HIV/AIDS Cohort Study started in 2006 and enrolled HIV patients from 21 tertiary and secondary hospitals in South Korea. The data for CD4+ cell counts at diagnosis and HAART initiation from these HIV patients were analyzed by three-year time intervals and presented by number of CD4+ cells (≤100, 101-200, 201-350, 351-500 and >500 cells/mm³). The HIV-RNA titer at diagnosis and HAART initiation were presented by 3-year intervals by groups ≤50,000, 50,001-100,000, 100,001-200,000, 200,001-1,000,000, and >1,000,000 copies/mL.

Results

Median values of CD4+ cell count and HIV-RNA titer at initial HIV diagnosis were 247 cells/mm³ and 394,955 copies/mL, respectively. At time of initiating HAART, median values of CD4+ cell count and HIV-RNA were 181 cells/mm³ and 83,500 copies/mL, respectively. Patients with low CD4+ cell count (CD4+ cell count ≤200 cells/mm³) at diagnosis (31-51%) and initiation of HAART accounted for the largest proportion (30-65%) over the three-year time intervals. This proportion increased until 2010-2012.

Conclusion

CD4+ cell count at initiation of HAART was found to be very low, and the increase in late initiation of HAART in recent years is of concern. We think that this increase is primarily due to an increasing proportion of late presenters. We recommend early detection of HIV patients and earlier start of HAART in order to treat and prevent spread of HIV infection.

Revised definition of predicted left ventricular mass using ambulatory blood pressure in healthy Korean adults

Background

Left ventricular hypertrophy is influenced by both hemodynamic and non-hemodynamic factors. Ambulatory blood pressure is correlated with left ventricular hypertrophy. We established the influences of hemodynamic and non-hemodynamic factors, including ambulatory blood pressure, on variation in left ventricular mass in healthy Korean adults.

Method

We included 172 subjects (male = 71, female = 101), with normal body mass index and blood pressure, in an analysis of data from the Yangpyung and Yeoju cohort studies and a tertiary cardiovascular center. Left ventricular mass was calculated using the equation: [1.04 × (IVSd + LVDd + PWTd) ³-(LDVs³)] × 0.8 + 0.6. Stroke volume was calculated (mL/beat) using Teichholz’s formula. Stroke work (SW in gram-meters/beat [g-m/beat]) was computed as ambulatory systolic BP × stroke volume × 0.0144.

Results

Stroke work was the most important determinant associated with left ventricular mass (adjusted R² = 0.442, p < 0.001), independent of height^2.7 and sex. In a regression model including stroke work, height,^2.7 and sex, the left ventricular mass was predicted by the equation: 43.11 + 0.61 × SW (g-m/beat) + 9.21 × height^2.7-13.99 × sex (male = 1, female = 2) (constant = 43.11 ± 25.88, adjusted R² = 0.532, p < 0.001).

Conclusion

We examined ambulatory blood pressure, as in previous studies, and identified stroke work, height^2.7, and sex as important determinants of left ventricular mass in Korean adults of normal weight and normal blood pressure. Ambulatory blood pressure is superior to clinical blood pressure for determining stroke work and predicted left ventricular mass.