Assessment of Disease Burden and Immunization Rates for Vaccine-Preventable Diseases in People Living with HIV: The Korea HIV/AIDS Cohort Study

BACKGROUND

Prophylactic immunization is important for human immunodeficiency virus (HIV)-infected patients; however, there are insufficient data on the burden of vaccine-preventable diseases (VPDs), vaccination rates, and factors influencing vaccination.

MATERIALS AND METHODS

The incidence and prevalence of VPDs in HIV-infected patients between 2006 and 2017 were estimated using the Korean HIV/acquired immune deficiency syndrome (AIDS) cohort database. In addition, we evaluated the vaccination rates and influencing factors for vaccination in HIV-infected patients through multilevel analysis of clinico-epidemiological factors, immune status, and psychological status. A questionnaire survey was conducted among experts to determine whether they recommend vaccination for HIV-infected patients.

RESULTS

The incidence rates of hepatitis B virus (HBV) infection, herpes zoster, and anogenital warts were 1.74, 7.38, and 10.85 per 1,000 person-years, respectively. The prevalence of HBV infection and anogenital warts at enrollment was 4.8% and 8.6%, respectively, which increased to 5.3% and 12.0%, respectively, by 2017. In HIV-infected patients, HBV (21.7% in 2008, 56.3% in 2013, and 75.4% in 2017) and pneumococcal vaccination rates (3.0% in 2015, 7.6% in 2016, and 9.6% in 2017) increased annually, whereas the influenza vaccination rate remained similar by season (32.7 - 35.6%). In the multilevel analysis, peak HIV viral load (≥50 copies/mL: odds ratio [OR] = 0.64, 95% confidence interval [CI]: 0.44 - 0.93; reference, <50 copies/mL) was an influencing factor for pneumococcal vaccination, while nadir CD4 T-cell counts (200 - 350 cells/mm3: OR = 0.54, 95% CI: 0.38 - 0.76; <200 cells/mm3: OR = 0.89, 95% CI: 0.62 - 1.28; reference, ≥350 cells/mm3) was an influencing factor for HBV vaccination. Influenza vaccination was associated with male sex (OR = 1.94) and the number of antiretroviral therapy (ART) regimen change (OR = 1.16), but was not significantly associated with HIV viral load or CD4 T-cell counts. Most experts responded that they administer hepatitis A virus, HBV, pneumococcal, and influenza vaccines routinely, but not human papillomavirus (12.9%) or herpes zoster vaccines (27.1%).

CONCLUSION

The burden of vaccine-preventable diseases was quite high in HIV-infected patients. Nadir CD4 T-cell counts, peak HIV viral loads, and the number of ART regimen change are significant factors related to vaccination. Considering the low vaccination rates for VPDs, there was a discordance between experts' opinions and real clinical practice in the medical field.

Trends for syndromic surveillance of norovirus in emergency department data based on chief complaints

BACKGROUND

This study compared the trends in norovirus cases to determine whether chief complaint-based emergency department (ED) visits data could reflect trends of norovirus in Korea.

METHODS

The ED visits from the National Emergency Department Information System (NEDIS) database and the weekly reported number of noroviruses from the sentinel surveillance system were collected between August 2017 and December 2020. The correlation between weekly norovirus cases and weekly ED visits considering the chief complaint and discharge diagnosis code was estimated using a three-week moving average.

RESULTS

In total, 6,399,774 patients with chief complaints of digestive system disease visited ED. A higher correlation between reported norovirus cases and ED visit with chief complaint of vomiting and discharge diagnosis code of gastroenteritis and colitis of unspecified origin or other and unspecified gastroenteritis and colitis of infectious origin was observed (R=0.88, p<.0001). The correlation was highest for the 0-4-years age group (R=0.89, p<.0001). However, no correlation was observed between the reported norovirus cases and the number of emergency department visits with norovirus identified as a discharge diagnosis code.

CONCLUSIONS

ED visit data considering a combination of chief complaints and discharged diagnosis code would be available for early detection of infectious disease trends.

BLZ8 activates a plastidial peroxiredoxin and a ferredoxin to protect Chlamydomonas reinhardtii against oxidative stress

Reactive oxygen species (ROS) cause damage to various cellular processes in almost all organisms, in particular photosynthetic organisms that depend on the electron transfer chain for CO2 fixation. However, the detoxifying process to mitigate ROS damage has not been studied intensively in microalgae. Here, we characterized the ROS detoxifying role of a bZIP transcription factor, BLZ8, in Chlamydomonas reinhardtii. To identify downstream targets of BLZ8, we carried out comparative genome-wide transcriptomic profiling of BLZ8 OX and its parental CC-4533 under oxidative stress conditions. Luciferase reporter activity assays and RT-qPCR were performed to test whether BLZ8 regulates downstream genes. We performed an in silico functional gene network analysis and an in vivo immunoprecipitation assay to identify the interaction between downstream targets of BLZ8. Comparative transcriptomic analysis and RT-qPCR revealed that overexpression of BLZ8 increased the expression levels of plastid peroxiredoxin1 (PRX1) and ferredoxin-5 (FDX5) under oxidative stress conditions. BLZ8 alone could activate the transcriptional activity of FDX5 and required bZIP2 to activate transcriptional activity of PRX1. Functional gene network analysis using FDX5 and PRX1 orthologs in A. thaliana suggested that these two genes were functionally associated. Indeed, our immunoprecipitation assay revealed the physical interaction between PRX1 and FDX5. Furthermore, the complemented strain, fdx5 (FDX5), recovered growth retardation of the fdx5 mutant under oxidative stress conditions, indicating that FDX5 contributes to oxidative stress tolerance. These results suggest that BLZ8 activates PRX1 and FDX5 expression, resulting in the detoxification of ROS to confer oxidative stress tolerance in microalgae.

Effect of characteristics on the clinical course at the initiation of treatment for human immunodeficiency virus infection using dimensionality reduction

The beginning of human immunodeficiency virus (HIV) infection treatment depends on various factors, which are significantly correlated with the initial CD4 cell number. However, a covariate correlation between these factors may not reflect the correct outcome variable. Thus, we evaluated the effects of a combination of fixed factors (reduced dimensions), which determine when to start treatment for the first time, on short-term outcome, long-term outcome, and survival, considering correlations between factors. Multiple correspondence analysis was performed on variables obtained from 925 patients who participated in a Korean HIV/acquired immunodeficiency syndrome cohort study (2006-2017). Five reduced dimension groups were derived according to clinical data, viral load, CD4 cell count at diagnosis, initial antiretroviral therapy, and others. The dimension group with high initial viral loads (55,000 copies/mL) and low CD4 cell counts (< 200 cells/mm³) should start treatment promptly after diagnosis. Groups with high initial CD4 cell counts (> 350 cells/mm³) that did not require immediate treatment according to previous guidelines had a higher failure rate for long-term relative CD4 recovery. Our results highlight the importance of early diagnosis and treatment to positively influence long-term disease outcomes, even if the initial immune status is poor, given the patient's combination of early diagnostic symptoms.

Association of Dietary Antioxidant Vitamin Intake and Gastric Cancer Risk According to Smoking Status and Histological Subtypes of Gastric Cancer: A Case-Control Study in Korea

Smoking is a risk factor for gastric cancer (GC) and causes oxidative stress. Antioxidant vitamins may protect against oxidative stress. This study aimed to determine the association between dietary antioxidant vitamin intake and GC risk according to smoking status and the histological subtype. This case-control study included 286 pairs of patients with GC and controls aged 20-79 years enrolled at two hospitals from 2002 to 2006, matched by age (± 2 years), sex, hospital, and participation period (± 1 years). Dietary information was collected using a quantitative food frequency questionnaire (FFQ). When stratified by smoking status, increased intake of vitamin C (OR = 0.38; 95% CI = 0.17-0.84 for highest vs. lowest; P for trend = 0.033) and folate (OR = 0.28; 95% CI = 0.12-0.64 for highest vs. lowest; P for trend = 0.003) decreased GC risk in nonsmokers. Vitamin C (P for interaction = 0.043) and folate (P for interaction =0.015) levels were significantly associated with smoking status. Similar results were observed in nonsmokers with diffuse and mixed types of GC, but not in those with intestinal type of GC. Therefore, we found an inverse association between higher intake of dietary vitamin C and folate with the risk of GC among nonsmokers. These protective associations were strong in nonsmokers with diffuse and mixed types of GC.

Rate of and Risk Factors for Loss to Follow Up in HIV-Infected Patients in Korea: The Korea HIV/AIDS Cohort Study

BACKGROUND

Owing to antiretroviral therapy (ART), acquired immune deficiency syndrome (AIDS)-related mortality has significantly decreased. Retaining in care is an essential step for human immunodeficiency virus (HIV) care cascade. This study investigated the incidence of and risk factors for loss to follow-up (LTFU) in Korean people living with HIV (PLWH).

MATERIALS AND METHODS

Data from the Korea HIV/AIDS cohort study (including prospective interval cohort and retrospective clinical cohort) were analyzed. LTFU was defined as not visiting the clinic for more than 1 year. Risk factors for LTFU were identified using the Cox regression hazard model.

RESULTS

The study enrolled 3,172 adult HIV patients (median age, 36 years; male 92.97%). The median CD4 T cell count at enrollment was 234 cells/mm³ (interquartile range [IQR]: 85 - 373) and the median viral load at enrollment was 56,100 copies/mL (IQR: 15,000 - 203,992). The total follow-up duration was 16,487 person-years, and the overall incidence rate of LTFU was 85/1,000 person-years. In the multivariable Cox regression model, subjects on ART were less likely to have LTFU than subjects not on ART (hazard ratio [HR] = 0.253, 95% confidence interval [CI]: 0.220-0.291, P <0.0001). Among PLWH on ART, female sex (HR = 0.752, 95% CI: 0.582-0.971, P = 0.0291) and older age (>50: HR = 0.732, 95% CI: 0.602 - 0.890; 41 - 50: HR = 0.634, 95% CI: 0.530 - 0.750; 31 - 40: HR = 0.724, 95% CI: 0.618 - 0.847; ≤30: reference, P <0.0001) were associated with high rate of retention in care. The viral load at ART initiation ≥1,000,001 (HR = 1.545, 95% CI: 1.126 - 2.121, ≤10,000: reference) was associated with a higher rate of LTFU.

CONCLUSION

Young and male PLWH may have a higher rate of LTFU, and an increased rate of LTFU may induce virologic failure.

Association between soy products, fruits, vegetables, and dairy products and gastric cancer risk in Helicobacter pylori-infected subjects: a case-control study in Korea

BACKGROUND/OBJECTIVES

Consumption of certain protective foods may help inhibit Helicobacter pylori (H. pylori) associated gastric pathologies. However, studies conducted to assess the efficacy of protective foods in H. pylori-infected subjects are either limited or inconsistent. This study evaluated the association of individual or a combination of protective foods on the incidence of gastric cancer (GC) in H. pylori-positive subjects through a case-control study.

MATERIALS/METHODS

Subjects aged 20-79 years were selected from 2 hospitals between December 2002 and September 2006. In total, 134 patients and 212 controls tested positive for H. pylori infection. Among these, we included 82 pairs of cases and controls matched by sex, age (± 5 years), enrollment period (± 1 years), and hospital.

RESULTS

A higher intake of soy products was associated with a significantly lower risk of GC than a lower intake of soy products (odds ratio [OR] = 0.37, 95% confidence interval [CI] = 0.14-0.96). Additionally, a higher fruit intake resulted in a significantly lower risk of GC than a lower fruit intake (OR = 0.35, 95% CI = 0.13-0.94). A combination of food groups was evaluated, and a lower risk of GC was observed with a high intake of both soy products and fruits (OR = 0.20, 95% CI = 0.06-0.67), high intake of soy and dairy products (OR = 0.28, 95% CI = 0.10-0.78) and high intake of fruits and dairy products (OR = 0.28, 95% CI = 0.09-0.83).

CONCLUSIONS

A high intake of soy products or fruits was associated with a lower risk of GC. A combination of soy products or fruits with dairy products was associated with a lower risk of GC. A balanced intake of soy products, fruits, and dairy products may help reduce GC risk.

Dietary zinc intake and mortality in patients with intestinal-type gastric cancer: A prospective cohort study in Korea

Purpose

Current evidence regarding the association between zinc intake and gastric cancer (GC)-specific survival in patients with intestinal-type GC is lacking. Therefore, this cohort study investigated the association between zinc intake and GC mortality through follow-up on GC death among patients with intestinal-type GC and whether these effects differ according to the source of zinc intake.

Methods

A total of 185 patients with intestinal-type GC were enrolled from two hospitals between 2002 and 2006. Their survival or death was prospectively followed up until December 31, 2016, through a review of medical records and telephone surveys.

Results

A total of 178 patients were included and analyzed. The median follow-up period was 7.3 years. In the fully adjusted models, the highest tertile of total zinc intake showed a significantly lower GC mortality than the lowest tertile (hazard ratio, 0.22; 95% confidence interval: 0.08–0.64). In addition, the tertile of total zinc intake showed a dose-response association with GC mortality (p=0.015). Analysis of the source of zinc intake revealed that when zinc intake from staples (rice and noodles), animal, and plant food sources were combined, the results were similar to those of total zinc intake and GC mortality.

Conclusion

Zinc intake through various foods may be effective in reducing GC mortality by achieving balance with other nutrients. Our results suggest that zinc improves the survival of patients with intestinal-type GC in Korea.

Forecasting Hospital Visits Due to Influenza Based on Emergency Department Visits for Fever: A Feasibility Study on Emergency Department-Based Syndromic Surveillance

This study evaluated the use of chief complaint data from emergency departments (EDs) to detect the increment of influenza cases identified from the nationwide medical service usage and developed a forecast model to predict the number of patients with influenza using the daily number of ED visits due to fever. The National Health Insurance Service (NHIS) and the National Emergency Department Information System (NEDIS) databases from 2015 to 2019 were used. The definition of fever included having an initial body temperature ≥ 38.0 °C at an ED department or having a report of fever as a patient's chief complaint. The moving average number of visits to the ED due to fever for the previous seven days was used. Patients in the NHIS with the International Classification of Diseases-10 codes of J09, J10, or J11 were classified as influenza cases, with a window duration of 100 days, assuming the claims were from the same season. We developed a forecast model according to an autoregressive integrated moving average (ARIMA) method using the data from 2015 to 2017 and validated it using the data from 2018 to 2019. Of the 29,142,229 ED visits from 2015 to 2019, 39.9% reported either a fever as a chief complaint or a ≥38.0 °C initial body temperature at the ED. ARIMA (1,1,1) (0,0,1)₇ was the most appropriate model for predicting ED visits due to fever. The mean absolute percentage error (MAPE) value showed the prediction accuracy of the model. The correlation coefficient between the number of ED visits and the number of patients with influenza in the NHIS up to 14 days before the forecast, with the exceptions of the eighth, ninth, and twelfth days, was higher than 0.70 (p-value = 0.001). ED-based syndromic surveillances of fever were feasible for the early detection of hospital visits due to influenza.

Gastric Cancer Risk Was Associated with Dietary Factors Irritating the Stomach Wall: A Case-Control Study in Korea

The incidence of gastric cancer is high in Korea, and dietary factors are important risk factors for gastric cancer. This study examined whether gastric cancer risk was related to dietary factors that directly irritate the stomach wall. This case−control study consisted of 308 matched pairs of gastric cancer cases and controls recruited from 2002 to 2006 at two hospitals in Korea. Dietary assessments were completed using a food frequency questionnaire and a dietary habit questionnaire. Gastric cancer risk was increased for high meal frequency of >3 vs. low meal frequency of ≤3 times per day, overeating vs. not overeating, and preferred vs. not preferred spicy or salty foods. Furthermore, participants with dietary factors of high meal frequency, overeating, and preference for spicy or salty foods elevated the risk of gastric cancer compared to those with low meal frequency, not overeating, and not preferring spicy or salty foods, simultaneously. In conclusion, gastric cancer risk was significantly increased in people with dietary factors that irritate the stomach wall, such as high meal frequency, overeating, and preference for spicy or salty foods.

Trends in gastrointestinal infections before and during nonpharmaceutical interventions in Korea in comparison with the United States

OBJECTIVES

This study examined how trends in the weekly frequencies of gastrointestinal infectious diseases changed before and during the coronavirus disease 2019 (COVID-19) pandemic in Korea, and compared them with the trends in the United States.

METHODS

We compared the weekly frequencies of gastrointestinal infectious diseases (16 bacterial and 6 viral diseases) in Korea during weeks 5-52 before and after COVID-19. In addition, the weekly frequencies of 5 gastrointestinal infectious diseases in the United States (data from the Centers for Disease Control and Prevention) that overlapped with those in Korea were compared.

RESULTS

The mean weekly number of total cases of gastrointestinal infectious diseases in Korea showed a significant decrease (from 522 before COVID-19 to 245 after COVID-19, p<0.01). Only bacterial gastrointestinal infectious diseases caused by Campylobacter increased significantly; other bacterial gastrointestinal infectious diseases showed either a decrease or no change. The incidence of all other viral diseases decreased. In the United States, the weekly numbers of Salmonella, Campylobacter, typhoid, shigellosis, and hepatitis A virus cases sharply decreased after the COVID-19 outbreak. The weekly case numbers of all viral diseases markedly decreased in both countries; however, bacterial gastrointestinal infectious diseases showed a different pattern.

CONCLUSIONS

The incidence of gastrointestinal infectious diseases decreased after the COVID-19 outbreak. In contrast, Campylobacter infections showed an increasing trend in Korea, but a decreasing trend in the United States. Further studies are needed to elucidate the different trends in bacterial and viral infectious diseases before and after non-pharmaceutical interventions and between different countries.

The Incidence and Risk Factors of Renal Insufficiency among Korean HIV infected Patients: The Korea HIV/AIDS Cohort Study

Renal insufficiency is one of the common issues in people living with human immunodeficiency virus (PLHIV). We studied the incidence and risk factors for renal insufficiency in male PLHIV using the Korea HIV/acquired immunodeficiency syndrome (AIDS) Cohort Study. Among the 830 enrolled patients, 32 (3.9%) cases of renal insufficiency occurred over 9576 patient-years of follow-up. The incidence of renal insufficiency in HIV-infected men in this study was 3.3 per 1000 patient-years. Diabetes mellitus, dyslipidemia, tenofovir or non-nucleoside reverse transcriptase inhibitor exposure for >1 year, and AIDS-defining illness were risk factors for renal insufficiency.

Comparison of Three Cardiovascular Risk Scores among HIV-Infected Patients in Korea: The Korea HIV/AIDS Cohort Study

Background

We investigated cardiovascular disease (CVD), risk factors for CVD, and applicability of the three known CVD risk equations in the Korean human immunodeficiency virus/ Acquired Immune Deficiency Syndrome (HIV/AIDS) cohort.

Materials and Methods

The study parcitipants were HIV-infected patients in a Korean HIV/AIDS cohort enrolled from 19 hospitals between 2006 and 2017. Data collected at entry to the cohort were analyzed. The 5-year CVD risk in each participant was calculated using three CVD risk equations: reduced CVD prediction model of HIV-specific data collection on adverse effects of anti-HIV drugs (R-DAD), Framingham general CVD risk score (FRS), and Korean Coronary Heart Disease Risk Score (KRS).

Results

CVD events were observed in 11 of 586 HIV-infected patients during a 5-year (median) follow-up period. The incidence of CVD was 4.11 per 1,000 person-years. Older age (64 vs. 41 years, P = 0.005) and diabetes mellitus (45.5% vs. 6.4%, P <0.001) were more frequent in patients with CVD. Using R-DAD, FRS, and KRS, 1.9%, 2.4%, and 0.7% of patients, respectively, were considered to have a very high risk (≥10%) of 5-year CVD. The discriminatory capacities of the three prediction models were good, with c-statistic values of 0.829 (P <0.001) for R-DAD, 0.824 (P <0.001) for FRS, and 0.850 (P = 0.001) for KRS.

Conclusion

The FRS, R-DAD, and KRS performed well in the Korean HIV/AIDS cohort. A larger cohort and a longer period of follow-up may be necessary to demonstrate the risk factors and develop an independent CVD risk prediction model specific to Korean patients with HIV.

Dietary Intake of Soy Products, Vegetables, and Dairy Products and Gastric Cancer Survival according to Histological Subtype: a Long-term Prospective Cohort Study

PURPOSE

Owing to differences in the general characteristics of gastric cancer (GC) according to histological type, the association of GC risk factors, such as diet, may also differ depending on the histological type. We investigated the associations between individual and combined intake of soy products, vegetables, and dairy products and GC mortality by following up cases of death among Korean GC cases and whether these associations differ according to the histological type.

MATERIALS AND METHODS

A total of 508 GC cases were enrolled from two hospitals between 2002 and 2006. Their survival or death was prospectively followed up until December 31, 2016, through a review of medical records and telephonic surveys. Finally, 300 GC cases classified as intestinal- or diffuse-type GC cases were included. The median follow-up period was 7.1 years.

RESULTS

In the fully adjusted model, a high intake of soy products (hazard ratio [HR], 0.43; 95% confidence interval [CI], 0.19-0.96) and the combination of soy products and vegetables (HR, 0.34; 95% CI, 0.12-0.96) or soy products and dairy products (HR, 0.37; 95% CI, 0.14-0.98) decreased the mortality from intestinal-type GC. In particular, patients consuming various potentially protective foods (HR, 0.23; 95% CI, 0.06-0.83) showed a highly significant association with a lower mortality from intestinal-type GC. However, no significant association was found with diffuse-type GC.

CONCLUSIONS

High intake of potentially protective foods, including soy products, vegetables, and dairy products, may help increase survival in intestinal-type GC.

Association Between Relative Quadriceps Strength and Type 2 Diabetes Mellitus in Older Adults: The Yangpyeong Cohort of the Korean Genome and Epidemiology Study

BACKGROUND

To examine the independent and combined association between relative quadriceps strength and the prevalence of type 2 diabetes mellitus (T2DM) in older adults.

METHODS

Among 1441 Korean older adults aged ≥65 years (71 [4.7] y) recruited between 2007 and 2016, 1055 older adults with no history of myocardial infarction, stroke, or cancer were included in the analysis. Cases of T2DM were identified by self-reported physician diagnosis, use antihyperglycemic medication or insulin, or fasting blood glucose ≥126 mg/dL. Logistic regression was used to calculate the odds ratios and 95% confidence intervals of T2DM by quartiles of relative quadriceps strength.

RESULTS

There were 162 T2DM cases (15%). Compared with the lowest quartile (weakest), the odds ratios (95% confidence intervals) of T2DM were 0.56 (0.34-0.90), 0.60 (0.37-0.96), and 0.47 (0.28-0.80) in the second, third, and fourth quartiles, respectively, after adjusting for possible confounders, including body mass index. In the joint analysis, compared with the "weak and overweight/obese" group, the odds (odds ratios [95% confidence intervals]) of T2DM was only lower in the "strong and normal weight" group (0.36 [0.22-0.60]) after adjusting for possible confounders.

CONCLUSIONS

Greater relative quadriceps strength is associated with reduced odds of T2DM in older adults after adjusting for potential confounders including body mass index.

485Prospective associations between sex hormone-binding globulin and risk of type 2 diabetes

Background

Circulating sex hormone–binding globulin levels are inversely associated with insulin resistance. However, epidemiologic evidence on the association of sex hormone-binding globulin (SHBG) and the risk of developing diabetes is limited. This study aimed to evaluate the prospective associations between serum SHBG level and risk of type 2 diabetes (T2D) among adults ≥ 40 years old in the Yangpyeong and Namwon cohort.

Methods

A total of 4,383 (1,651 men and 2,732 women) participants who did not have T2D were enrolled. The incidence rate ratio (IRR) was estimated using a modified Poisson regression model with a robust error estimator. During follow-up (27,146 person-years), 284 T2D cases were newly diagnosed.

Results

Significant dose-response inverse associations were observed between serum SHBG (tertiles) and T2D in women, even after controlling for baseline fasting glucose (incidence rate ratio, IRR=0.42, 95% CI = 0.26–0.68, P for trend = &lt;.001 in the highest tertile). Similar significant linear trends were found among menopausal women, and the inverse associations persisted across participant subgroups with diabetes risk profiles. However, there were no significant associations with serum SHBG in men. When we examined the association, except for men with higher levels of hs-CRP (≥ 3 mg/L) and HOMA-IR (≥ 2.5) at baseline, the non-significant associations did not change (IRR=1.45, 95% CI = 0.78–2.70, P for trend=0.167 in the highest tertile). The sex-specific differences in associations between serum SHBG and T2D risk were statistically significant (P for interaction=0.005).

Conclusions

Serum SHBG may be inversely associated with T2D in women, but not in men.

Key messages

Circulating SHBG may play different roles in the development of T2D in men and women.

Associations between relative grip strength and type 2 diabetes mellitus: The Yangpyeong cohort of the Korean genome and epidemiology study

Objective

To investigate the association between relative grip strength and the prevalence of type 2 diabetes mellitus (T2DM) independently and in combination with body mass index (BMI) in Korean adults.

Methods

The cross-sectional study includes 2,811 men and women (age 40 to 92 years old) with no history of heart disease, stroke, or cancer. Relative grip strength was measured by a handheld dynamometer and calculated by dividing absolute grip strength by body weight. Logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of T2DM by sex-specific quintiles of relative grip strength. In a joint analysis, participants were classified into 4 groups: “weak (lowest 20% quintile one) and normal weight (BMI <25.0 kg/m²)”, “weak and overweight/obese (BMI ≥25.0 kg/m²)”, “strong (upper 80% four quintiles) and normal weight” or “strong and overweight/obese”.

Results

Among the 2,811 participants, 371 were identified as having T2DM. Compared with the lowest quintile of relative grip strength (weakest), the ORs (95% CIs) of T2DM were 0.73 (0.53–1.02), 0.68 (0.48–0.97), 0.72 (0.50–1.03), and 0.48 (0.32–0.74) in upper quintiles two, three, four, and five, respectively, after adjusting for BMI and other potential confounders. In the joint analysis, compared with the “weak and overweight/obese” reference group, the odds of T2DM [ORs (95% CIs)] was lower in the “strong and overweight/obese” group [0.65 (0.46–0.92)] and the “strong and normal weight” group [0.49 (0.35–0.67)], after adjusting for potential confounders.

Conclusion

In this cross-sectional study, greater relative grip strength was associated with a lower prevalence of T2DM independent of BMI in Korean adults. Additional prospective studies are needed to determine whether a causal association exists between relative grip strength and T2DM prevalence considering BMI.

Independent and interactive associations of season, dietary vitamin D, and vitamin D-related genetic variants with serum 25(OH)D in Korean adults aged 40 years or older

Only limited information is available on the inter-relationships between genetic and non-genetic factors such as diet and sunlight exposure with serum 25-hydroxyvitamin D [25(OH)D] concentration. This cross-sectional study aimed to examine the independent and interactive associations of season, dietary vitamin D intake, and SNPs of 11 vitamin D-related candidate genes with serum 25(OH)D concentration among 2,721 adults aged ≥40 years at baseline from the Yangpyeong cohort, a part of the Korean Genome Epidemiology Study (KoGES). The interactions between season or dietary vitamin D and 556 SNPs were evaluated using 2-degree of freedom joint tests. Season was strongly (p_difference = 1.00 × 10^-12) and dietary vitamin D intake was slightly but significantly associated with serum 25(OH)D concentration (p_difference = 0.0119). Among five SNPs (rs11723621-GC, rs7041-GC, rs10500804-CYP2R1, rs7129781-CYP2R1, and rs2852853-DHCR7) identified in the screening steps, only one, rs10500804-CYP2R1, significantly interacted with season (p_interaction = 8.01 × 10^-5). The inverse association between number of minor alleles of rs10500804-CYP2R1 and concentration of 25(OH)D was significant only in summer/fall. Conversely, dietary vitamin D intake was positively associated only in winter/spring. In conclusion, season, dietary vitamin D intake, and four SNPs in GC, CYP2R1, and DHCR7 are independently and rs10500804-CYP2R1 is interactively associated with serum 25(OH)D concentration. Serum 25(OH)D is influenced by genotype of rs10500804-CYP2R1 in summer/fall when sunlight exposure is high, while dietary vitamin D intake is an important determinant of serum 25(OH)D during the seasons with low cutaneous vitamin D synthesis.

A Long-Term Incidence of Heart Failure and Predictors Following Newly Developed Acute Myocardial Infarction: A 10 Years Retrospective Cohort Study with Korean National Health Insurance Data

Heart failure (HF) is the major mechanism of mortality in acute myocardial infarction (AMI) during early or intermediate post-AMI period. But heart failure is one of the most common long-term complications of AMI. Applied the retrospective cohort study design with nation representative population data, this study traced the incidence of late-onset heart failure since 1 year after newly developed acute myocardial infarction and assessed its risk factors. Methods and Results: Using the Korea National Health Insurance database, 18,328 newly developed AMI patients aged 40 years or older and first hospitalized in 2010 for 3 days or more, were set up as baseline cohort (12,403). The incidence rate of AMI per 100,000 persons was 79.8 overall, and 49.6 for women and 112.3 for men. A total of 2010 (1073 men, 937 women) were newly developed with HF during 6 years following post AMI. Cumulative incidences of HF per 1000 AMI patients for a year at each time period were 37.4 in initial hospitalization, 32.3 in 1 year after discharge, and 8.9 in 1-6 years. The overall and age-specific incidence rates of HF were higher in women than men. For late-onset HF, female, medical aid, pre-existing hypertension, severity of AMI, duration of hospital stay during index admission, reperfusion treatment, and drug prescription pattern including diuretics, affected the occurrence of late-onset HF. Conclusion: With respect to late-onset HF following AMI, appropriate management including hypertension and medical aid program in addition to quality improvement of AMI treatment are required to reduce the risk of late-onset heart failure.

Prospective Associations of Dietary Intakes of Total Antioxidant Capacity and Its Subclasses With Metabolic Syndrome in Adults Aged 40 Years and Older

Objectives

This study aimed to evaluate the association between dietary intakes of total antioxidant capacity (TAC) and its subclasses (flavonoids and its individual subclass and individual vitamins) and incidence risk of Metabolic syndrome (MetS) in the KoGES_CArdioVascular disease Association Study (CAVAS).

Methods

A total of 11,272 participants over 40 years of age who did not have MetS from CAVAS were enrolled. Cumulative average TAC and flavonoid intake were calculated from repeated food frequency questionnaires composed of 106 items using data during follow-up. Using a modified Poisson regression model, we estimated incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for MetS in men and women separately and subsequently pooled these results.

Results

Over 56,425 person-year of follow-up, there were 2,218 incident cases of MetS. While both TAC and flavonoids were inversely associated with MetS development in the pooled multivariable analysis (fourth vs. first quartile, IRR: 0.88; 95% CI 0.76–1.01 for TAC and 0.83, 0.73, 0.95 for flavonoids), there were relatively clear inverse associations between intake of certain subclasses and incidence of MetS. Among flavanones, theaflavins, anthocyanins, and carotenoids were obvious inversely associated with MetS (0.57; 0.50, 0.65 for flavanones, 0.55; 0.48, 0.63 for anthocyanins, 0.60; 0.52, 0.69 for carotenoids). However, the associations were relatively weak in flavones and flavonols (0.96; 0.84, 1.10 for flavones and 0.84; 0.73, 0.96 for flavonols).

Conclusions

Intake of specific antioxidants such as flavanones, anthocyanins, carotenoids may provide health benefits in preventing MetS. More prospective studies are warranted to elucidate the association between TAC and individual subclasses and the incidence of MetS and chronic disease.

Funding Sources

This work was supported by the Research Program funded by the Korea Centers for Disease Control and Prevention (2004-E71004–00, 2005-E71011–00, 2006-E71009–00, 2007-E71002–00, 2008-E71004–00, 2009-E71006–00, 2010-E71003–00, 2011-E71002–00, 2012-E71007–00, 2013-E71008–00, 2014-E71006–00, 2014-E71006–01, 2016-E71001–00, 2017N-E71001–00) and was supported the National Research Foundation of Korea(NRF) grant funded by the Korea government (MSIT) (No. NRF-2020R1A2C1004815).

Status and Determinants of Treatment Outcomes Among New Tuberculosis Patients in South Korea: A Retrospective Cohort Study

This is a retrospective cohort study using notification data in South Korea. We evaluated the nationwide status, regional differences, and the determinants of treatment outcomes among tuberculosis patients. Treatment success rate improved from 77.0% in 2012 to 86.0% in 2015. The lost to follow-up rate was higher among older people, males, and foreign nationals. Health care facilities designated for the Public-Private Mix (PPM) project showed higher success rate and lower rate of lost to follow-up. Moreover, municipalities with low regional deprivation index had higher PPM project coverage. Since there is a large regional difference in the coverage of the PPM project, an additional community-based support program should be implemented, especially for tuberculosis patients residing in region with low PPM project coverage.

Factors affecting the survival of early COVID-19 patients in South Korea: An observational study based on the Korean National Health Insurance big data

OBJECTIVES

This study aimed to identify the survival rate and explore factors affecting survival among early COVID-19 patients in South Korea.

METHODS

Data reported by the Korea Disease Control and Prevention Agency (KDCA), up to 15 July, when COVID-19 was confirmed were used as research data in connection with the National Health Insurance Service's (NHIS) national health information database. The final analysis targets were 12,646 confirmed patients and 303 deaths. The survival rate of patients with COVID-19 was estimated through Kaplan-Meier survival analysis. Cox proportional hazard regression analysis was performed to search for factors affecting survival.

RESULTS

When looking at the survival rate by age group for men and women, the 28-day survival rate for men aged >80 years was 77% and 73% at 42 days, while 83% and 81% for women. Men had a worse survival rate than women. For chronic diseases, the highest risk of mortality was observed in malignant neoplasms of the respiratory and urogenital systems, followed by diseases of the urinary system and diabetes.

CONCLUSIONS

The number of COVID-19 deaths was highest the next day after initial diagnosis. The case fatality rate was high in males, older age, and chronic diseases.

Objectively Measured Built Environments and Cardiovascular Diseases in Middle-Aged and Older Korean Adults

This study assesses the association between the objectively measured built environment and cardiovascular diseases (CVDs) in 50,741 adults from the Korean Community Health Survey. The CVD outcomes of hypertension, diabetes, dyslipidemia, stroke, and myocardial infarction (MI) or angina were derived from self-reported histories of physician diagnoses. Using ArcGIS software and Korean government databases, this study measured the built environment variables for the 546 administrative areas of Gyeonggi province. A Bayesian spatial multilevel model was performed independently in two age groups (i.e., 40–59 years or ≥60 years). After adjusting for statistical significant individual- and community-level factors with the spatial associations, living far from public transit was associated with an increase in the odds of MI or angina in middle-aged adults, while living in neighborhoods in which fast-food restaurants were concentrated was associated with a decrease in the odds of hypertension and stroke. For adults 60 or older, living farther from public physical-activity (PA) facilities was associated with a 15% increased odds for dyslipidemia, compared with living in neighborhoods nearer to PA facilities. These findings suggest that creating a built environment that provides more opportunities to engage in PA in everyday life should be considered a strategy to reduce the prevalence of CVD.

Associations of depression and anxiety with cardiovascular risk among people living with HIV/AIDS in Korea

OBJECTIVES

As HIV/AIDS is becoming a chronic disease, the risk of developing cardiovascular disease (CVD) among people living with HIV/AIDS is rising. Anxiety and depression, which are common among people living with HIV/AIDS, have been linked with CVD. This study investigated the risk of CVD in people living with HIV/AIDS and explored the effects of depression and anxiety on CVD risk.

METHODS

Data were collected for 457 people enrolled in the Korea Cohort HIV/AIDS study after 2010. Framingham risk scores were calculated to quantify the 10-year risk of developing CVD. Depression and anxiety variables were re-coded as a single combined variable. Multivariable logistic regression analysis was performed, adjusting for age, body mass index, low-density lipoprotein (LDL) cholesterol, triglycerides (TG), duration of human immunodeficiency virus (HIV) positivity after entry into the cohort, and depression/anxiety.

RESULTS

Participants with both depression and anxiety were 2.28 times more likely than those with neither depression nor anxiety to have moderate/high-risk CVD risk. The 10-year risk of developing CVD was affected by LDL cholesterol, TG, age, and duration of HIV infection. LDL cholesterol and TG levels change according to the duration of HIV infection, and metabolic disorders affect the risk of CVD. Thus, a longer duration of HIV infection is associated with a higher risk of developing CVD.

CONCLUSIONS

Screenings for depression and anxiety need to be provided regularly to assess the severity of those symptoms. To help decrease their risk of developing CVD, people living with HIV/AIDS should be offered behavioral modification interventions aimed at developing healthy lifestyle habits.

Fall characteristics among elderly populations in urban and rural areas in Korea

Falling is one of the leading causes of injury among elderly populations. As the population over 65 years old increases, medical costs due to falling will also increase. Urban and rural areas have different fall characteristics, and research into these differences is lacking.A survey was conducted on 2012 people over 60 years old between September 1, 2015, to October 12, 2015. Guro-gu (Seoul), Yeongdeungpo-gu (Seoul), and Jung-gu (Daegu) were classified as urban areas and included 1205 of the study participants. Dalseong-gun (Daegu) and Yangpyeong-gun (Gyeonggi-do) were categorized as rural areas and included 807 participants. The survey included questions about fall history, cause, season and time of recent falls, and external conditions associated with recent falls, like floor or ground materials and shoe types.Rural respondents were older than urban respondents (P < .001) but did not differ significantly in gender proportion (P = .082). Fall history over the past year was not different between the 2 regions (P = .693), but lifetime fall history was greater among rural respondents (P < .001). Only 5.1% of all respondents had undergone fall-prevention education. A slippery floor was the most common cause of falls in both regions, but there was a significant difference in pattern of fall causes (P < .001). Falls were more frequent in the summer, spring, and the afternoon in urban areas, and in the summer, autumn, and the morning in rural areas. Cement and asphalt were the most common ground materials at the time of falls in both regions, but rural respondents had higher fall rates when walking on soil and when wearing slippers.A fall-prevention program that reflects the characteristics and differences of falls in urban and rural areas should be developed and used to effectively prevent falling among elderly people.

Factors Affecting the Incidence of Hospitalized Pneumonia after Influenza Infection in Korea Using the National Health Insurance Research Database, 2014-2018: Focusing on the Effect of Antiviral Therapy in the 2017 Flu Season

BACKGROUND

This study aimed to investigate the effect of antiviral therapy following influenza outpatient episodes on the incidence of hospitalized pneumonia episodes, one of secondary complications of influenza.

METHODS

In the National Health Insurance Research Database, data from July 2013 to June 2018 were used. All of the claim data with diagnoses of influenza and pneumonia were converted to episodes of care after applying 100 days of window period. With the 100-day episodes of care, the characteristics of influenza outpatient episodes and antiviral therapy for influenza, the incidence of hospitalized pneumonia episodes following influenza, and the effect of antiviral therapy for influenza on hospitalized pneumonia episodes were investigated.

RESULTS

The crude incidence rate of hospitalized pneumonia after influenza infection was 0.57% in both males and females. Factors affecting hospitalized pneumonia included age, income level except self-employed highest (only in females), municipality, medical institution type, precedent chronic diseases except hepatitis (only in females) and antiviral therapy. In the 2017 flu season, the relative risk was 0.38 (95% confidence interval [CI], 0.29-0.50) in males aged 0-9 and 0.43 (95% CI, 0.32-0.57) in females aged 0-9 without chronic diseases, and it was 0.51 (95% CI, 0.42-0.61) in males aged 0-9 and 0.42 (95% CI, 0.35-0.50) in females aged 0-9 with one or more chronic diseases in the aspect of the effect of antiviral therapy on pneumonia. It suggests that antiviral therapy may decrease the incidence of pneumonia after influenza infection.

CONCLUSION

After outpatient episode incidence of influenza, antiviral treatment has been shown to reduce the incidence of hospitalized pneumonia, especially in infants and children, during pandemic season 2017. Antiviral therapy for influenza is recommended to minimize burden caused by influenza virus infection and to reduce pneumonia. In addition, medical costs of hospitalization may decrease by antiviral therapy, especially in infants and children.

Prospective cohort data quality assurance and quality control strategy and method: Korea HIV/AIDS Cohort Study

OBJECTIVES

The aim of effective data quality control and management is to minimize the impact of errors on study results by identifying and correcting them. This study presents the results of a data quality control system for the Korea HIV/AIDS Cohort Study that took into account the characteristics of the data.

METHODS

The HIV/AIDS Cohort Study in Korea conducts repeated measurements every 6 months using an electronic survey administered to voluntarily consenting participants and collects data from 21 hospitals. In total, 5,795 sets of data from 1,442 participants were collected from the first investigation in 2006 to 2016. The data refining results of 2015 and 2019 were converted into the data refining rate and compared.

RESULTS

The quality control system involved 3 steps at different points in the process, and each step contributed to data quality management and results. By improving data quality control in the pre-phase and the data collection phase, the estimated error value in 2019 was 1,803, reflecting a 53.9% reduction from 2015. Due to improvements in the stage after data collection, the data refining rate was 92.7% in 2019, a 24.21%p increase from 2015.

CONCLUSIONS

Despite this quality management strategy, errors may still exist at each stage. Logically possible errors for the post-review refining of downloaded data should be actively identified with appropriate consideration of the purpose and epidemiological characteristics of the study data. To improve data quality and reliability, data management strategies should be systematically implemented.

Survival Trend of HIV/AIDS Patients Starting Antiretroviral Therapy in South Korea between 2001 and 2015

PURPOSE

In the recent antiretroviral therapy (ART) era, a large proportion of Korean patients with human immunodeficiency virus (HIV) infection were shown to have low CD4 cell counts at diagnosis and during ART initiation. We investigated the survival trends in patients living with HIV/acquired immunodeficiency syndrome (AIDS) in Korea who started ART in the 2000s, and evaluated the risk factors for mortality to elucidate the association between survival and low CD4 cell counts at ART initiation.

MATERIALS AND METHODS

Patients with HIV infection who were aged >18 years and had started ART between 2001 and 2015 in the Korean HIV/AIDS cohort study were enrolled. We compared the clinical characteristics, mortality, and causes of death among the enrolled subjects based on the time of ART initiation. Cox regression analysis was used to estimate the adjusted hazard ratios of mortality based on the time of ART initiation.

RESULTS

Among the 2474 patients enrolled, 105 (4.24%) died during the follow-up period of 9568 patient-years. Although CD4 cell counts at the time of ART initiation significantly increased from 161 [interquartile range (IQR), 73.5-303] in 2001-2003 to 273 (IQR, 108-399) in 2013-2015 (p<0.001), they remained low during the study period. The incidence of all-cause mortality was 10.97 per 1000 patient-years during the study period. There was no decreasing trend in mortality between 2001 and 2015. Age >40 years [adjusted hazard ratio, 3.71; 95% confidence interval (CI), 2.35-5.84] and low CD4 counts (<100 cells/mm³: adjusted hazard ratio, 2.99; 95% CI, 1.44-6.23) were significant risk factors for mortality.

CONCLUSION

Despite excellent HIV care available in the recent ART era, the survival of patients with HIV/AIDS undergoing ART did not improve between 2001 and 2015 in Korea.

Time-variant reproductive number of COVID-19 in Seoul, Korea

OBJECTIVES

To estimate time-variant reproductive number (R_t) of coronavirus disease 19 based on either number of daily confirmed cases or their onset date to monitor effectiveness of quarantine policies.

METHODS

Using number of daily confirmed cases from January 23, 2020 to March 22, 2020 and their symptom onset date from the official website of the Seoul Metropolitan Government and the district office, we calculated R_t using program R’s package “EpiEstim”. For asymptomatic cases, their symptom onset date was considered as -2, -1, 0, +1, and +2 days of confirmed date.

RESULTS

Based on the information of 313 confirmed cases, the epidemic curve was shaped like ‘propagated epidemic curve’. The daily R_t based on R_{t_c} peaked to 2.6 on February 20, 2020, then showed decreased trend and became <1.0 from March 3, 2020. Comparing both R_t from R_{t_c} and from the number of daily onset cases, we found that the pattern of changes was similar, although the variation of R_t was greater when using R_{t_c}. When we changed assumed onset date for asymptotic cases (-2 days to +2 days of the confirmed date), the results were comparable.

CONCLUSIONS

R_t can be estimated based on R_{t_c} which is available from daily report of the Korea Centers for Disease Control and Prevention. Estimation of R_t would be useful to continuously monitor the effectiveness of the quarantine policy at the city and province levels.

Age-Period-Cohort Analysis of Influenza in Koreans: the National Health Insurance Research Database, 2009-2018

BACKGROUND

This study aimed to identify the incidence rate of episodes diagnosed with influenza and the effects of age-period-cohort (APC) in Koreans.

METHODS

The 2009-2018 National Health Insurance Research Database was used for analysis. All time-related claims connected relatively short window period in 100 days. The case definition was defined by all codes diagnosed with J09, J10, and J11. Calculation of the incidence rate and APC analysis adjusted income levels by insurance type, metropolitan city was performed to identify the characteristics of episodes diagnosed with influenza.

RESULTS

Incidence rate by age and cohort gradually increased since 2014. The incidence rate of males aged 0-4 years was 171.02 and that of females was 173.31 in 2015-2016 season. In males, 29.19 in 1963 cohort and 243.79 in 2013 cohort were confirmed as high incidence rates in 2017-2018 season. In the females, a high incidence was confirmed in 1953-1967 cohort and 1978-1987 cohort, and the incidence was 251.38 in 2013-2017 cohort. APC effects showed a high relative risk in the infants, the pandemic influenza season in 2010 (1/7/2009 to 30/6/2010) and the adults of 1978-1987 cohort.

CONCLUSION

Since 2014, influenza outbreaks have been increasing every year. The start year of free vaccination decreased the incidence in infants and adults over 65 years of age but the incidence increased from the following year. Because influenza can be primarily prevented by vaccination, reinforcement of vaccination in infants may reduce the disease burden in their parents, and also the risk of infection caused by family transmission. A new vaccination strategy is needed to reduce the incidence and burden of diseases caused by influenza infection.

Sex-specific associations of habitual intake of soy protein and isoflavones with risk of type 2 diabetes

BACKGROUND & AIMS

A possible mechanism by which intake of soy isoflavones leads to an improvement in glucose metabolism has been suggested. However, epidemiological evidence of a link between dietary soy isoflavone and type 2 diabetes is not convincing. This study aimed to evaluate the prospective associations between intake of dietary soy protein and isoflavones (total isoflavones, daidzein and genistein) and risk of type 2 diabetes in a community-based cohort of Korean adults aged ≥ 40 years, the Korean Multi-Rural Communities Cohort (MRCohort).

METHODS

A total of 8269 participants who did not have type 2 diabetes were enrolled. Dietary intake was calculated using a food frequency questionnaire.

RESULTS

Over 50,063 person-years of follow-up, 531 participants developed type 2 diabetes. Significant dose-response inverse associations were observed between dietary soy protein and isoflavones (quartiles) and type 2 diabetes in women (incidence rate ratio, IRR = 0.63, 95% CI = 0.45-0.87, P for trend = 0.0078 for soy protein; IRR = 0.62, 95% CI = 0.45-0.86, P for trend = 0.0031 for total isoflavones for the highest quartile compared with the lowest quartile). Similar significant linear trends were found for both daidzein and genistein. However, there were no significant associations with soy protein and isoflavones in men. The sex-specific differences in associations between soy protein and isoflavones intakes and type 2 diabetes risk were statistically significant (all P for interaction < 0.05).

CONCLUSIONS

Habitual intake of soy protein and isoflavones may be inversely associated with type 2 diabetes in women, but not in men. Dietary soy components may play different roles in the development of type 2 diabetes in men and women.

Dietary iodine, seaweed consumption, and incidence risk of metabolic syndrome among postmenopausal women: a prospective analysis of the Korean Multi-Rural Communities Cohort Study (MRCohort)

PURPOSE

Despite a beneficial role of iodine and seaweed consumption against metabolic syndrome (MetS), which is high in postmenopausal women, few studies investigated such associations in a prospective study. This study aimed to investigate the association of dietary iodine and seaweed consumption with the incidence of MetS and its components in postmenopausal women.

METHODS

A total of 2588 postmenopausal women aged ≥ 40 years were recruited between 2005 and 2011 in the Multi-Rural Communities Cohort (MRCohort). A validated semiquantitative food frequency questionnaire was used to collect dietary intake data. MetS was defined as three of five components [abdominal obesity, elevated blood pressure, glucose, triglyceride, and low-high density lipoprotein cholesterol (HDL-C)] and the incidence of MetS was checked every 2-4 years. The incidence rate ratio (IRR) was estimated using a modified Poisson regression model with a robust error estimator.

RESULTS

During the mean follow-up period (3.4 ± 2.1 years), MetS occurred in 481 participants. The median cumulative average iodine intake was 108.9 µg/day (interquartile range, 60.8-190.2 µg/day). In multivariable analyses, average iodine and seaweed consumption were inversely associated with MetS (IRR = 0.61, 95% CI 0.47-0.78 in the highest quartile of iodine intake, P for trend = 0.0018; IRR = 0.52, 95% CI 0.39-0.69 in the highest quartile of seaweed consumption, P for trend = 0.0004). Among MetS components, blood glucose (> 100 mg/dL), blood pressure (≥ 130/85 mmHg), and lipid profiles (triglyceride, ≥ 150 mg/dL and HDL-C, < 50 mg/dL) were significantly inversely associated with dietary iodine and seaweed consumption, but there was no clear association for waist circumference (≥ 85 cm).

CONCLUSION

Dietary iodine and seaweed consumption may be inversely associated with MetS incidence and its individual abnormalities in postmenopausal women.

Association of dietary glycaemic index, glycaemic load, and total carbohydrates with incidence of type-2 diabetes in adults aged ≥40 years: The Multi-Rural Communities Cohort (MRCohort)

AIMS

To examine potential associations between the glycaemic index (GI), glycaemic load (GL), and carbohydrates and the incidence risk of type-2 diabetes (T2D) and the effect modification of obesity among Korean adults aged ≥40 years.

METHOD

Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for T2D were estimated in 8310 participants using a modified Poisson regression model. Dietary indices were averaged using repeated dietary assessments during follow-up.

RESULT

After adjusting for potential confounders, a positive association between GI and T2D was found among women (IRR = 1.63, 95% CI = 1.06-2.51 in the highest tertile (T3) vs. the lowest tertile (T1) for GI, p trend = 0.0310), but not for GL and carbohydrate intake. This positive association with GI was stronger in obese women (IRR = 1.91, 95% CI: 1.15-3.19 in T3 vs. T1, p trend = 0.0137 for body mass index ≥23 kg/m²; IRR = 2.35, 95% CI: 1.01-5.48, p trend = 0.0350 for waist circumference (WC) ≥ 85 cm). In men, there was no association before stratification by obesity, but IRRs of GI (T3 vs. T1) were significant and stronger with increased WCs (IRR = 2.26, 95% CI: 1.02-4.98, p trend = 0.0439 for WC ≥ 90 cm).

CONCLUSION

GI may be positively associated with the incidence of T2D in women, particularly in obese women. The association of GI with T2D incidence risk may also be positive even in men with high WC.

Significance of Decreasing Rate of HIV and HBV Co-infection in a Nationwide Korean HIV/AIDS Cohort

From December 2006 to December 2016, 1093 human immunodeficiency virus (HIV) individuals < 70 years enrolled in Korea human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) cohort were analyzed to investigate the prevalence of HIV/HBV co-infection rate and hepatitis B virus surface antibody (HBsAb) positive rate based on birth year. The HBV co-infection prevalence rate was the highest (8.8%) in patients born between 1960 and 1964 and the lowest (0%) among those born between 1995 and 1999. A decreasing linear trend of HBV co-infection rate was observed according to the 5-year interval changes. HBsAb-positive rate was only 58.1% in our study. The national HBV vaccination programs have effectively lowered the HBV co-infection rate in HIV population. However, it is identified that the HIV population has low HBsAb positive rate. Further evidences supporting efficacy of booster immunization for HBsAb negative HIV patients are required and efforts should be made to increase HBsAb positive rates among HIV patients to prevent horizontal transmission.

Prediagnostic Smoking and Alcohol Drinking and Gastric Cancer Survival: A Korean Prospective Cohort Study

Background/Aims

Behavioral factors, such as smoking and heavy alcohol consumption, increase the risk of gastric cancer (GC), but their effects on survival are not clear. We examined associations between prediagnostic smoking and alcohol drinking behavior and GC death by long-term follow-up.

Methods

The participants were 508 GC patients enrolled at Chungnam University Hospital and Hanyang University Guri Hospital from 2001 to 2006. Information on clinicopathologic and behavioral risk factors was collected, and patient survival was prospectively followed until 2016 by medical chart review and telephone survey.

Results

During above 10 years follow-up period, overall death was 46.2% (n=226) and GC deaths was 38.2% (n=187) among the 489 GC patients included in the analysis. No significant association was found between smoking habits and overall or GC survival. However, after stratification by histological type, the hazard ratio (HR) of GC death for current smokers tended to be higher for the diffuse type (HR 1.61, 95% CI 0.57-4.59 for current vs. never) rather than for the intestinal type (HR 0.78, 95% CI 0.28-2.19 for current vs. never). Light alcohol consumption was found to be associated with a significantly lower risk of GC death (HR 0.52, 95% CI 0.36-0.75 for <20 g/day for women or <40 g/day for men vs. never and past), and the effects of alcohol drinking habits had similar effects on GC death for the intestinal and diffuse types.

Conclusions

These results suggest smoking and alcohol drinking behaviors before a diagnosis of GC are weakly associated with GC survival. Nevertheless, the effect of smoking behavior on prognosis appears to depend on the histological type of GC.

Prospective associations between total, animal, and vegetable calcium intake and metabolic syndrome in adults aged 40 years and older

BACKGROUND & AIMS

Calcium (Ca) consumption may contribute to a decreased risk of developing metabolic syndrome (MetS). However, epidemiologic evidence on the association between Ca intake and MetS is limited. This study aimed to evaluate the association between dietary Ca intake (animal-based Ca and vegetable-based Ca separately, as well as total Ca intake) and the incidence risk of MetS and its components in the Korean Multi-Rural Communities Cohort (MRCohort).

METHODS

A total of 5509 participants who did not have MetS were enrolled. Dietary Ca intake was calculated using a food frequency questionnaire composed of 106 items.

RESULTS

After 18,880 person-years of follow-up, 876 participants had developed de novo MetS. A significant inverse association between dietary total Ca intake and MetS were observed (incidence rate ratio (IRR) = 0.62, 95% confidence interval (CI) = 0.48-0.81, P for trend = 0.002 for the highest quartile of total Ca intake compared with the lowest quartile). Trends for animal Ca (IRR = 0.77, 95% CI = 0.62-0.97, P for trend = 0.039) and vegetable Ca (IRR = 0.54, 95% CI = 0.40-0.73, P for trend <0.001) were similar. The individual components of overall MetS were also inversely related to total, animal, and vegetable Ca. The tendency for an inverse association was more evident in the group with two of any of the metabolic abnormalities of MetS at baseline than in the group with no more than one MetS component.

CONCLUSIONS

Our findings indicate that a relatively high dietary intake of Ca is associated with lower risk of MetS.

Influence of Neighborhood Environment on Korean Adult Obesity Using a Bayesian Spatial Multilevel Model

Previous studies using spatial statistical modeling that account for spatial associations between geographic areas are scarce. Therefore, this study examines the association between neighborhood environment and obesity using a Bayesian spatial multilevel model. Data from 78,014 adults living in Gyeonggi province in Korea were drawn from the 2013–2014 Korean Community Health Survey. Korean government databases and ArcGIS software (version 10.1, ESRI, Redlands, CA) were used to measure the neighborhood environment for 546 administrative districts of Gyeonggi province. A Bayesian spatial multilevel model was implemented across gender and age groups. The findings indicate that women aged 19–39 years who lived in neighborhoods farthest away from parks were more likely to be obese. Men aged 40–59 years who lived in neighborhoods farther from public physical activity facilities and with lower population density were more likely to be obese. Obesity for women aged 19–39 years was the most spatially dependent, while obesity for women aged 40–59 years was the least spatially dependent. The results suggest that neighborhood environments that provide more opportunities for physical activity are negatively related to obesity. Therefore, the creation of physical activity in favorable neighborhood environments, considering gender and age, may be a valuable strategy to reduce obesity.

Significance of Increased Rapid Treatment from HIV Diagnosis to the First Antiretroviral Therapy in the Recent 20 Years and Its Implications: the Korea HIV/AIDS Cohort Study

From December 2006 to December 2016, 1,429 patients enrolled in the Korea human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) Cohort Study were investigated. Based on the year of diagnosis, the time interval between HIV diagnosis and initiation of antiretroviral therapy (ART) was analyzed by dividing it into 2 years. The more recent the diagnosis, the more likely rapid treatment was initiated (P < 0.001) and the proportion of patients starting ART on the same day of HIV diagnosis was increased in 2016 (6.5%) compared to that in 2006 (1.7%). No significant difference in the median values of CD4+ cell counts according to the diagnosis year was observed. In the past 20 years, the time from the HIV diagnosis to the initiation of ART was significantly reduced. Rapid treatment was being implemented at the HIV diagnosis, regardless of CD4+ cell count. Considering the perspective "treatment is prevention," access to more rapid treatment is necessary at the time of HIV diagnosis.

Causes and countermeasures for repeated outbreaks of hepatitis A among adults in Korea

The 2019 hepatitis A outbreak has become increasingly prevalent among adults in Korea and is the largest outbreak since that in 2009-2010. The incidence in the current outbreak is highest among adults aged 35-44 years, corresponding to the peak incidence among those aged 25-34 years 10 years ago. This may indicate a cohort effect in the corresponding age group. Causes of these repeated outbreaks of hepatitis A in Korea are low level of immunity among adults, Korean food culture that consumes raw seafood such as salted clam and inadequate public health system. Among countermeasures, along with general infectious disease control measures including control of the infectious agent, infection spread, and host, urgent actions are needed to review the vaccination policy and establish an adequate public health system.

Alcohol consumption and gastric cancer risk in Korea: a case-control study

BACKGROUND/OBJECTIVES

The International Agency for Research on Cancer defined alcohol beverages and acetaldehyde derived from alcoholic beverages as a Group 1 carcinogen to humans. However, the association between alcohol consumption and gastric cancer risk has been controversial in Korean. We assessed the relationship between alcohol consumption and gastric cancer risk in Korea through a case-control study.

SUBJECTS/METHODS

From 2 hospitals, a total of 316 cases with gastric cancer (208 men, 108 women) were selected and matched to 316 controls by sex and age (± 5 years) during the same duration. The current status, frequency, and amount of alcohol consumption for a year three years ago were assessed by trained interviewers.

RESULTS

Alcohol consumption status and frequency did not show any significant association with gastric cancer risk. However, high alcohol consumption (≥ 20 g/day for women or ≥ 40 g/day for men) significantly increased the risk of gastric cancer (odds ratio (OR) 1.73; 95% confidence interval (CI) 1.05–2.85). Gastric cancer risk was strongly positively associated with alcohol consumption of ≥ 20 g/day, especially in women (OR 5.62; 95% CI 1.32–23.81).

CONCLUSION

The results from this study suggest that excessive alcohol consumption rather than the current status or frequency of alcohol consumption contributes to the increased risk of gastric cancer, especially in women.

Epidemiological characteristics of HIV infected Korean: Korea HIV/AIDS Cohort Study

OBJECTIVES

To manage evidence-based diseases, it is important to identify the characteristics of patients in each country.

METHODS

The Korea HIV/AIDS Cohort Study seeks to identify the epidemiological characteristics of 1,442 Korean individuals with human immunodeficiency virus (HIV) infection (12% of Korean individuals with HIV infection in 2017) who visited 21 university hospitals nationwide. The descriptive statistics were presented using the Korea HIV/AIDS cohort data (2006-2016).

RESULTS

Men accounted for 93.3% of the total number of respondents, and approximately 55.8% of respondents reported having an acute infection symptom. According to the transmission route, infection caused by sexual contact accounted for 94.4%, of which 60.4% were caused by sexual contact with the same sex or both males and females. Participants repeatedly answered the survey to decrease depression and anxiety scores. Of the total participants, 89.1% received antiretroviral therapy (ART). In the initial ART, 95.3% of patients were treated based on the recommendation. The median CD4 T-cell count at the time of diagnosis was 229.5 and improved to 331 after the initial ART. Of the patients, 16.6% and 9.4% had tuberculosis and syphilis, respectively, and 26.7% had pneumocystis pneumonia. In the medical history, sexually transmitted infectious diseases showed the highest prevalence, followed by endocrine diseases. The main reasons for termination were loss to follow-up (29.9%) and withdrawal of consent (18.7%).

CONCLUSIONS

Early diagnosis and ART should be performed at an appropriate time to prevent the development of new infection.

Impact of age on stage-specific mortality in patients with gastric cancer: A long-term prospective cohort study

Controversies exist regarding the impact of age on gastric cancer-related mortality according to cancer stage. In our prospective cohort study, we evaluated the impact of age on stage-specific mortality in patients with gastric cancer. Between 2002 and 2006, patients with newly diagnosed gastric cancer were recruited from two university-affiliated hospitals in Korea. Follow-up data were updated regularly based on medical records and telephone surveys. Patients were classified into four subgroups according to age: <50, 50-59, 60-69, and 70-79 years. A total of 448 patients were followed up for 81.6 months (interquartile range, 25.0-139.3 months). The number of patients with stage I, II, III, and IV disease was 247, 74, 88, and 39, respectively. Overall, age was an independent risk factor for gastric cancer-specific mortality (hazard ratio [HR], [95% confidence interval (CI)]: 1.53 [0.91-2.57], 1.88 [1.21-2.91], and 2.64 [1.69-4.14] in the 50-59, 60-69, and 70-79 years groups, respectively, with the <50 years group as reference). In patients with stage I and II gastric cancer, the 70-79 years group was associated with a significantly higher rate of cancer-specific mortality than the <50 years group (stage I: HR [95% CI], 9.55 [2.11-43.12]; stage II: HR [95% CI], 7.17 [2.32-22.18]). However, age was not an independently associated factor for cancer-specific mortality in patients with stage III and IV gastric cancer. Although age was an independent risk factor for gastric cancer-related mortality in patients with gastric cancer, its impact may differ depending on the stage of cancer.

Meta-Analysis of Genome-Wide Association Studies Identifies Three Loci Associated With Stiffness Index of the Calcaneus

The stiffness index (SI) from quantitative ultrasound measurements is a good indicator of BMD and may be used to predict the risk of osteoporotic fracture. We conducted a genomewide association study (GWAS) for SI using 7742 individuals from the Taiwan Biobank, followed by a replication study in a Korean population (n = 2955). Approximately 6.1 million SNPs were subjected to association analysis, and SI-associated variants were identified. We further conducted a meta-analysis of Taiwan Biobank significant SNPs with a Korean population-based cohort. Candidate genes were prioritized according to epigenetic annotations, gene ontology, protein-protein interaction, GWAS catalog, and expression quantitative trait loci analyses. Our results revealed seven significant single-nucleotide polymorphisms (SNPs) within three loci: 7q31.31, 17p13.3, and 11q14.2. Conditional analysis showed that three SNPs, rs2536195 (CPED1/WNT16), rs1231207 (SMG6), and rs4944661 (LOC10050636/TMEM135), were the most important signals within these regions. The associations for the three SNPs were confirmed in a UK Biobank estimated BMD GWAS; these three cytobands were replicated successfully after a meta-analysis with a Korean population cohort as well. However, two SNPs were not replicated. After prioritization, we identified two novel genes, RAB15 and FNTB, as strong candidates for association with SI. Our study identified three SI-associated SNPs and two novel SI-related genes. Overall, these results provide further insight into the genetic architecture of osteoporosis. Further studies in larger East Asian populations are needed. © 2019 American Society for Bone and Mineral Research.

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.