New framework to assess tracing and testing based on South Korea's response to COVID-19

South Korea's remarkable success in controlling the spread of COVID-19 during the pre-Omicron period was based on extensive contact tracing and large-scale testing. Here we suggest a general criterion for tracing and testing based on South Korea's experience, and propose a new framework to assess tracing and testing. We reviewed papers on South Korea's response to COVID-19 to capture its concept of tracing and testing. South Korea expanded its testing capabilities to enable group tracing combined with preemptive testing, and to conduct open testing. According to our proposed model, COVID-19 cases are classified into 4 types: confirmed in quarantine, source known, source unknown, and unidentified. The proportion of the first two case types among confirmed cases is defined as "traced proportion", and used as the indicator of tracing and testing effectiveness. In conclusion, South Korea successfully suppressed COVID-19 transmission by maintaining a high traced proportion (> 60%) using group tracing in conjunction with preemptive testing as a complementary strategy to traditional contact tracing.

Association between accelerometer-derived physical activity and depression: a cross-sectional study using isotemporal substitution analysis

OBJECTIVES

Depression is a significant public health concern, and physical activity has been identified as a non-pharmacological intervention. Understanding the dose-response relationship between physical activity and depression is crucial for designing effective exercise interventions and recommending physical activity to individuals with depression. The isotemporal substitution model is considered the gold standard for estimating the dose-response effects of physical activity. This study aims to investigate the dose-response association between depression and accelerometer-measured physical activity in the Korean population.

DESIGN

Cross-sectional analysis.

SETTING

A non-probability sample of the community population was drawn from the 2014 and 2016 Korean National Health and Nutrition Examination Survey.

PARTICIPANTS

The study included 1543 adults aged 19-64 years who completed the Patient Health Questionnaire-9 (PHQ-9) and volunteered to wear an accelerometer.

MAIN OUTCOME MEASURES

Physical activity was measured using a GT3X+ accelerometer for 7 consecutive days, and activity was categorised as sedentary behaviour (SB) or light, moderate or vigorous physical activity. Depression was assessed using the PHQ-9.

RESULTS

Physical activity and SB were associated with depression. In the single-parameter model, moderate-vigorous physical activity (MVPA) showed a significant association with reduced odds of depression (OR: 0.817, 95% CI: 0.678 to 0.985). Substituting 30 min of SB with 30 min of MVPA (OR: 0.815, 95% CI: 0.669 to 0.992) was linked to a decrease in the odds of depression. Conversely, replacing 30 min of MVPA with 30 min of SB (OR: 1.227, 95% CI: 1.008 to 1.495) was associated with an increase in the odds of depression.

CONCLUSIONS

This study provides evidence of an association between physical activity and depression in the Korean population, highlighting the importance of reducing SB and increasing MVPA to prevent and manage depression. Further research is needed to confirm causality and determine optimal levels of physical activity for preventing depression in different populations.

Associations of meteorological factors and dynamics of scrub typhus incidence in South Korea: A nationwide time-series study

Scrub typhus, also known as Tsutsugamushi disease, is a climate-sensitive vector-borne disease that poses a growing public health threat. However, studies on the association between scrub typhus epidemics and meteorological factors in South Korea need to be complemented. Therefore, we aimed to analyze the association among ambient temperature, precipitation, and the incidence of scrub typhus in South Korea. First, we obtained data on the weekly number of scrub typhus cases and concurrent meteorological variables at the city-county level (Si-Gun) in South Korea between 2001 and 2019. Subsequently, a two-stage meta-regression analysis was conducted. In the first stage, we conducted time-series regression analyses using a distributed lag nonlinear model (DLNM) to investigate the association between temperature, precipitation, and scrub typhus incidence at each location. In the second stage, we employed a multivariate meta-regression model to combine the association estimates from all municipalities, considering regional indicators, such as mite species distribution, Normalized Difference Vegetation Index (NDVI), and urban-rural classification. Weekly mean temperature and weekly total precipitation exhibited a reversed U-shaped nonlinear association with the incidence of scrub typhus. The overall cumulative association with scrub typhus incidence peaked at 18.7 C° (with RRs of 9.73, 95% CI: 5.54-17.10) of ambient temperature (reference 9.7 C°) and 162.0 mm (with RRs of 1.87, 95% CI: 1.02-3.83) of precipitation (reference 2.8 mm), respectively. These findings suggest that meteorological factors contribute to scrub typhus epidemics by interacting with vectors, reservoir hosts, and human behaviors. This information serves as a reference for future public health policies and epidemiological research aimed at controlling scrub typhus infections.

Public support for tobacco endgame policies in South Korea: Findings from the 2020 International Tobacco Control Korea Survey

BACKGROUND

Strong public support can increase the likelihood of adopting tobacco control policies. We assessed support for six commercial tobacco endgame policies in South Korea: limiting the nicotine in cigarettes, banning all additives in cigarettes, restricting the number of places where cigarettes are sold, and banning the manufacture and sales of cigarettes (unconditionally, with the provision of cessation support and with alternative tobacco products available).

METHODS

Data were obtained from 4740 adults who completed the 2020 International Tobacco Control Korea Survey. Participants were categorised based on their nicotine use: (1) did not use any products, (2) vaped and/or used heated tobacco products (HTPs) but did not smoke cigarettes, (3) smoked cigarettes only and (4) smoked cigarettes and vaped and/or used HTPs. Attitudes towards the policies were classified as supportive, undecided or opposed. Weighted multinomial logistic regression models assessed support levels according to nicotine use.

RESULTS

Support was highest for limiting the nicotine content in cigarettes (68.4%; 95% CI 64.6% to 72.3%) and restricting the number of retailers (68.1%; 95% CI 64.5% to 71.7%), and lowest for banning cigarette sales if alternative products are made available (45.0%; 95% CI 40.9% to 49.1%). People who did not use any products were most likely to support endgame policies, except for banning cigarette sales with alternatives available. The proportion of undecided participants exceeded 10% (range 13%-25%) for all policies.

CONCLUSION

There is a strong public support for tobacco endgame policies in South Korea. Further research should prioritise the development of strategies to ensure the effective implementation of highly supported policies.

Factors influencing psychological concerns about COVID-19 in South Korea: direct and indirect damage during the early stages of pandemic

BACKGROUND

COVID-19 pandemic has led to psychological concerns, the distribution of which across populations may differ depending on whether pandemic-related damage is direct or indirect. This study aims to investigate concerns associated with direct and indirect damage according to population characteristics, and identify relatively vulnerable groups that are particularly affected by concerns.

METHOD

This cross-sectional study used data from the 2020 Korea Community Health Survey, which collected data based on a complex sampling design. A total of 208,106 responses from individuals aged ≥ 19 were collected via in-person interviews. The items related to COVID-19 concerns were measured by Likert scales ranging from 1 to 5 and categorized into two types: direct concerns, which pertained to infection or death, and indirect concerns, which pertained to criticism, vulnerability, and economic damage, through factor analysis. We compared the means and effect size of direct concerns, indirect concerns, and overall concerns using weighted mean, ANOVA, and multiple regression analysis.

RESULTS

Exploratory and confirmatory factor analyses supported a two-factor structure for psychological concerns about COVID-19 (CFI = 0.99, TLI = 0.97, SRMR = 0.02, RMSEA = 0.06), which were divided into direct and indirect concerns. Mean scores were 3.62 for direct concerns and 4.07 for indirect concerns. Direct concerns were higher in females (B = .26); the elderly (B = .15); those diagnosed with hypertension or diabetes (B = .04; B = .06); those with few assistants during quarantine (B = .15); and those whose neighbors responded inappropriately to COVID-19 (B = .07). Indirect concerns were lower among the elderly (B = -.04), and higher among young; married (B = .25); pink- or blue-collar workers (B = .08; B = .06); and those who felt that the city responded inappropriately to COVID-19 (B = .02).

CONCLUSION

The prevalence of concerns regarding direct and indirect damage caused by the COVID-19 pandemic differed according to population characteristics. Some factors had a marked influence on direct and indirect concerns. Our findings could inform psychological interventions and policies for future pandemics. Customized interventions are needed to prevent negative psychological concerns and improve mental health.

Decrease in household secondhand smoking among Korean adolescents associated with smoke-free policies: grade-period-cohort and interrupted time series analyses

OBJECTIVES

Smoke-free areas have expanded and related campaigns have been implemented since 1995 in Korea. As a result, household secondhand smoke (SHS) exposure has decreased over the past 15 years. We assessed the cohort effect, the effect of a 2008 campaign on household SHS exposure, and the impact of a complete smoking ban in public places along with increased penalties, as implemented in December 2011.

METHODS

Nationally representative cross-sectional 15-wave survey data of Korean adolescents were used. The 810,516 participants were classified into 6 grade groups, 15 period groups, and 20 middle school admission cohorts. An age-period-cohort analysis, conducted with the intrinsic estimator method, was used to assess the cohort effect of household SHS exposure, and interrupted-time series analyses were conducted to evaluate the effects of the smoke-free policy and the campaign.

RESULTS

For cohorts who entered middle school from 2002 to 2008, the risk of household SHS exposure decreased among both boys and girls. Immediately after implementation of the smoke-free policy, the prevalence of household SHS exposure by period decreased significantly for boys (coefficient, -8.96; p<0.05) and non-significantly for girls (coefficient, -6.99; p=0.07). After the campaign, there was a significant decrease in household SHS exposure by cohort among boys, both immediately and post-intervention (coefficient, -4.84; p=0.03; coefficient, -1.22; p=0.02, respectively).

CONCLUSIONS

A school-admission-cohort effect was found on household SHS exposure among adolescents, which was associated with the smoke-free policy and the campaign. Anti-smoking interventions should be implemented consistently and simultaneously.

Working hours, social engagement, and depressive symptoms: an extended work-life balance for older adults

BACKGROUND

In recent years, researchers have been examining the impact of work-life balance (WLB) on mental health, considering it as a potential risk factor. However, it remains unclear whether the traditional understanding of WLB applies to older adults who worked for fewer hours before full retirement and whose children are likely to be independent adults. Therefore, this study aims to propose a modified form of WLB specifically for older adults. Within this context, we hypothesize that an optimum balance between working hours and social engagement protects against depressive symptoms among older adults.

METHOD

We conducted an analysis using data on 5,751 Korean adults older than 55 years from the Korean Longitudinal Study of Aging 2016. Multivariate logistic regression analysis was used to evaluate the relationships among working hours, social engagement, and depressive symptoms.

RESULTS

Older adults who worked fewer than 35 h per week were less likely to experience depressive symptoms than were non-working older adults and those working 35 h or more per week. Additionally, older adults with a high level of informal social participation, thus occurring almost every day or two to three times per week, were less likely to experience depressive symptoms than were those with a low level of such participation (once a month or less). Furthermore, depressive symptoms were less frequent among those who worked fewer than 35 h per week and engaged in a high level of informal social participation compared to non-working older individuals and those with a low level of informal social participation.

CONCLUSIONS

Maintaining an optimal number of working hours and degree of social engagement are necessary to minimize the risk of depressive symptoms in older adults. Based on these findings, we suggest that fulfillment for work and life and their balance are important for older adults and propose work-life fulfillment balance.

Implication of findings from a two-wave survey on embitterment in South Korea for strategies to promote mental health of the general public

OBJECTIVE

To examine the prevalence of embitterment by following individuals over time and to statistically evaluate how factors known as correlates of embitterment affect different groups with or without changes in embitterment over time.

METHOD

Responses for the posttraumatic embitterment disorder (PTED) self-rating Scale were collected from the same 1,153 adults who participated in a follow-up survey delivered 14 months apart. Suggested cutoff points were applied to identify changes in embitterment and four groups were identified. For each group, the relative impacts of factors that affect changes in or maintenance of embitterment, such as negative life events (NLEs), belief in a just world (BJW), social support, relative deprivation, and resilience, were statistically analyzed.

RESULTS

The average PTED scores were relatively high for both surveys (M = 1.73 and 1.58, respectively). "Persistent" or "increased" in embitterment was seen for 47.3% of the participants. In particular, 15.3% (Wave 1) and 12.1% (Wave 2) of participants experienced clinically relevant levels of embitterment. NLEs, BJW, relative deprivation, and resilience showed significant associations with the risk of persistence or deterioration of embitterment.

CONCLUSIONS

Our study highlights embitterment as a dynamic emotion that can either be aggravated or moderated over time. Embitterment can be elicited by joint effects of multiple social and interactional factors including known embitterment correlates, and relative deprivation is confirmed as a possible core elicitor of embitterment in the context of comparative justice. These findings imply that additional longitudinal research and development of practices for mental health prevention in general populations are needed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Association between depression, anemia and physical activity using isotemporal substitution analysis

BACKGROUND

Depression is a leading cause of disability and mortality, with estimated number of deaths exceeding 2.2 million worldwide. We examined depression in relation to anemia and physical activity, both of which have an impact on depression mechanisms.

METHODS

This cross-sectional study used data from the Korean National Health and Nutrition Examination Survey, including 18,622 participants. Depression was measured by The Patient Health Questionnaire-9, and physical activity was assessed by the Global Physical Activity Questionnaire. Anemia was defined by World Health Organization criteria for blood hemoglobin levels. Isotemporal substitution model for physical activity was used to assess the effect of replacing sedentary behavior to each intensity level of physical activity. Logistic regression was applied to estimate the association on depression.

RESULTS

Replacing sedentary behavior with moderate or vigorous physical activity was associated with a lower risk of depression in the anemic (OR: 0.875, 95% CI: 0.782-0.978) and non-anemic groups (OR: 0.943, 95% CI: 0.919-0.967). Depression risk was significantly reduced by replacing walking with moderate to vigorous physical activity in both anemic (OR: 0.877, 95% CI: 0.784-0.982) and non-anemic groups (OR: 0.951, 95% CI: 0.927-0.976).

CONCLUSIONS

Moderate to vigorous physical activity had a protective association against depression in both anemic and non-anemic groups. Anemic patients are recommended to perform physical activity for any duration acceptable to them to prevent depression.

Analysis of the effectiveness of non-pharmaceutical interventions on influenza during the Coronavirus disease 2019 pandemic by time-series forecasting

BACKGROUND

Coronavirus disease 2019 (COVID-19) was first identified in South Korea during the 2019-2020 seasonal influenza epidemic. The social distancing measures, as effective non-pharmaceutical interventions (NPIs), adopted to mitigate the spread of COVID-19 might have influenced influenza activity. We evaluated IFV(influenza virus) activity during the COVID-19 pandemic and the effect of NPI intensity on influenza transmission.

METHODS

IFV activity and epidemic duration during COVID-19 pandemic were predicted under a counterfactual scenario with no NPIs against COVID-19. The Seasonal Autoregressive Integrated Moving Average Model was used to quantify the effects of NPIs on the transmission of influenza virus. Influenza-like illness/1000 outpatients and IFV positivity rate from the 2011-2012 to 2021-2022 seasons were used in this study.

RESULTS

Comparison of the 2020-2021 and 2021-2022 seasonal influenza activities with those in 2013-2019 showed that COVID-19 outbreaks and associated NPIs such as face mask use, school closures, and travel restrictions reduced the influenza incidence by 91%. Without NPIs against COVID-19, the rates of influenza-like illness and IFV positivity would have been high during the influenza epidemic season, as in previous seasons. NPI intensity decreased the transmission of influenza; the magnitude of the reduction increased as the intensity of social-distancing measures increased (weak social distancing; step-by-step daily recovery: 58.10%, strong social distancing; special quarantine measures: 95.12%).

CONCLUSIONS

Our results suggest that NPIs and personal hygiene can be used to suppress influenza transmission. NPIs against COVID-19 may be useful strategies for the prevention and control of influenza epidemics.

Use of geographically weighted regression models to inform retail endgame strategies in South Korea: application to cigarette and ENDS prevalence

BACKGROUND

Reducing tobacco retailer availability is a key tobacco endgame policy. The development and evaluation of retail-based policies require spatial methodologies. We modelled the prevalence of adult cigarette and electronic nicotine delivery system (ENDS) use according to tobacco retailer density, considering geographical variations.

METHODS

Registration data for tobacco retail businesses, a population-representative survey of South Koreans aged ≥19 years, and population and land area data were used. We merged the datasets according to geographical units. Ordinary least squares (OLS) and geographically weighted regression (GWR) analyses were conducted to model cigarette and ENDS use prevalence, respectively.

FINDINGS

Tobacco retailer density was associated with increased cigarette use prevalence in the OLS model (β=2.19, p=0.02). A 1.9-fold difference by region was identified for the coefficient, indicating an association with tobacco retailer density (minimum 1.39, maximum 2.65), in the GWR analysis. No significant association was present between tobacco retailer density and ENDS prevalence in either the OLS (β=0.24, p=0.37) or the GWR model (minimum 0.20, maximum 0.28).

CONCLUSION

Our results suggest the importance of using spatial methods to develop and evaluate retail-based endgame policies. The establishment of tobacco retailer databases by the introduction of licensing is necessary to develop and evaluate the effectiveness of tobacco retailer regulations.

Monday peak is unique to suicide? Comparison of weekly distribution by causes of death using national representative cohort database

INTRODUCTION

The excess suicide mortality on Monday was reported in numerous studies. However, it is uncertain that the uneven weekly distribution of deaths is observed among suicide, or common among various causes of death.

METHODS

Weekly distributions of suicide and other causes of death from 2012 to 2017 in South Korea were compared. Logistic regression models were fitted to investigate the association between causes of death and day-of-the-week effects. We also fitted conditional logistic regression models after age and gender matching.

RESULTS

A total of 1,622,213 deaths, including 80,492 suicide decedents, were analyzed. A total of 16.0% of suicide deaths occurred on Monday, whereas 12.4% on Saturday and 13.0% on Sunday. Suicide decedents were more likely to die on Monday than other causes of deaths after controlling sociodemographic factors in unmatched data. However, there was no evidence of excess suicide deaths on Mondays than other days in contrast to matched death controls.

CONCLUSION

While the increase in mortality on Mondays was not unique to suicide, our findings have suicide prevention implications. Mental health practitioners should consider providing additional mental health resources on earlier working days. Workplace mental health programs to reduce psychological burdens of employees could help to prevent suicide during working days.

All-Cause and Cause-Specific Mortality Attributable to Seasonal Influenza: A Nationwide Matched Cohort Study

BACKGROUND

Although influenza poses substantial mortality burden, most studies have estimated excess mortality using time-aggregated data. Here, we estimated mortality risk and population attributable fraction (PAF) attributed to seasonal influenza using individual-level data from a nationwide matched cohort.

METHODS

Individuals with influenza during four consecutive influenza seasons (2013-2017) (n = 5,497,812) and 1:4 age- and sex-matched individuals without influenza (n = 20,990,683) were identified from a national health insurance database. The endpoint was mortality within 30 days after influenza diagnosis. All-cause and cause-specific mortality risk ratios (RRs) attributed to influenza were estimated. Excess mortality, mortality RR, and PAF of mortality were determined, including for underlying disease subgroups.

RESULTS

Excess mortality rate, mortality RR, and PAF of all-cause mortality were 49.5 per 100,000, 4.03 (95% confidence interval [CI], 3.63-4.48), and 5.6% (95% CI, 4.5-6.7%). Cause-specific mortality RR (12.85; 95% CI, 9.40-17.55) and PAF (20.7%; 95% CI, 13.2-27.0%) were highest for respiratory diseases. In subgroup analysis according to underlying disorders, PAF of all-cause mortality was 5.9% (95% CI, 0.6-10.7%) for liver disease, 5.8% (95% CI, 2.9-8.5%) for respiratory disease, and 3.8% (95% CI, 1.4-6.1%) for cancer.

CONCLUSION

Individuals with influenza had a 4-fold higher mortality risk than individuals without influenza. Preventing seasonal influenza may lead to 5.6% and 20.7% reductions in all-cause and respiratory mortality, respectively. Individuals with respiratory disease, liver disease, and cancer may benefit from prioritization when establishing influenza prevention strategies.

Phylodynamic analysis revealed that human mobility and vaccination were correlated to the local spread of SARS-CoV-2 in Republic of Korea

Following the global emergence of the SARS-CoV-2 Alpha variant of concern (VOC) in 2020, the Delta variant triggered another wave in 2021. The AY.69 lineage, a Delta VOC, was particularly prevalent in Republic of Korea (South Korea) from May 2021 to January 2022, despite the synchronized implementation of vaccination programs and non-pharmaceutical interventions (NPIs) such as social distancing. In this study, we used phylogeographic analysis combined with a generalized linear model (GLM) to examine the impact of human movement and vaccination on viral transmission. Our findings indicated that transmission primarily originated in South Korea's metropolitan areas, and a positive correlation was observed between total human mobility (tracked by GPS on mobile phones and estimated through credit card consumption) and viral spread. The phylodynamic analysis further revealed that non-vaccinated individuals were the primary transmitters of the virus during the study period, even though vaccination programs had commenced three months prior to the AY.69 outbreak. Our study emphasizes the need to focus on controlling SARS-CoV-2 transmission in metropolitan regions and among unvaccinated populations. Furthermore, the positive correlation between mobility data and viral dissemination could contribute to the development of more accurate predictive models for local spread of pandemics.

Required biological time for lung maturation and duration of invasive ventilation: a Korean cohort study of very low birth weight infants

Background

We investigated the duration of invasive ventilation among very low birth weight (VLBW) infants to evaluate the current minimum time required for lung maturation to breathe without ventilator assistance after preterm birth.

Methods

A total of 14,658 VLBW infants born at ≤32⁺⁶ weeks between 2013 and 2020 were enrolled. Clinical data were collected from the Korean Neonatal Network, a national prospective cohort registry of VLBW infants from 70 neonatal intensive care units. Differences in the duration of invasive ventilation according to gestational age and birth weight were investigated. Recent trends and changes in assisted ventilation duration and associated perinatal factors between 2017-20 and 2013-16 were compared. Risk factors related to the duration of assisted ventilation were also identified.

Results

The overall duration of invasive ventilation was 16.3 days and the estimated minimum time required corresponded to 30⁺⁴ weeks of gestation. The median duration of invasive ventilation was 28.0, 13.0, 3.0, and 1.0 days at <26, 26-27, 28-29, and 30-32 weeks of gestation, respectively. In each gestational age group, the estimated minimum weaning points from the assisted ventilator were 29⁺⁵, 30⁺², 30⁺², and 31⁺⁵ weeks of gestation. The duration of non-invasive ventilation (17.9 vs. 22.5 days) and the incidence of bronchopulmonary dysplasia (28.1% vs. 31.9%) increased in 2017-20 (n = 7,221) than in 2013-16 (n = 7,437). In contrast, the duration of invasive ventilation and overall survival rate did not change during the periods 2017-20 and 2013-16. Surfactant treatment and air leaks were associated with increased duration of invasive ventilation (inverse hazard ratio 1.50, 95% CI, 1.04-2.15; inverse hazard ratio 1.62, 95% CI, 1.29-2.04). We expressed the incidence proportion of ventilator weaning according to the invasive ventilation duration using Kaplan-Meier survival curves. The slope of the curve slowly decreased as gestational age and birth weight were low and risk factors were present.

Conclusions

This population-based data on invasive ventilation duration among VLBW infants suggest the present limitation of postnatal lung maturation under specific perinatal conditions after preterm birth. Furthermore, this study provides detailed references for designing and/or assessing earlier ventilator weaning protocols and lung protection strategies by comparing populations or neonatal networks.

Vision for tobacco endgame in Korea: suggestions for countries with endgame aspirations

Tobacco endgame is a focal point of discussion at both national and international levels. We aimed to describe efforts related to achieving the tobacco endgame in the Republic of Korea, an exemplar of a country with endgame aspirations, and compare them with the efforts of other nations. We reviewed the tobacco endgame efforts of three nations considered tobacco control leaders: New Zealand (NZ), Australia and Finland. The efforts/attempts of each country were described using an endgame strategy category. The tobacco control leaders had explicit goals to achieve a smoking prevalence of <5% before a target date and had legislation and research centres for tobacco control and/or endgame. NZ is implementing a mixture of conventional and innovative endgame interventions; the others use incremental conventional approaches. In Korea, there has been an attempt to ban the sale and manufacture of combustible cigarettes. The attempt led to the filing of a petition, and a survey of adults showed 70% supported the legislation banning tobacco. The Korean government mentioned a tobacco endgame in a 2019 plan, yet a target and an end date were absent. The 2019 plan in Korea included incremental FCTC strategies. Practices in the leading countries show that legislation and research are key to ending the tobacco epidemic. The MPOWER measures must be strengthened, endgame objectives must be set and bold strategies must be adopted. Key endgame policies include those with evidence of effectiveness, such as retailer reductions.

Predicting Habitual Use of Wearable Health Devices Among Middle-aged Individuals With Metabolic Syndrome Risk Factors in South Korea: Cross-sectional Study

BACKGROUND

Prevention of the risk factors for metabolic syndrome (MetS) in middle-aged individuals is an important public health issue. Technology-mediated interventions, such as wearable health devices, can aid in lifestyle modification, but they require habitual use to sustain healthy behavior. However, the underlying mechanisms and predictors of habitual use of wearable health devices among middle-aged individuals remain unclear.

OBJECTIVE

We investigated the predictors of habitual use of wearable health devices among middle-aged individuals with risk factors for MetS.

METHODS

We proposed a combined theoretical model based on the health belief model, the Unified Technology of Acceptance and Use of Technology 2, and perceived risk. We conducted a web-based survey of 300 middle-aged individuals with MetS between September 3 and 7, 2021. We validated the model using structural equation modeling.

RESULTS

The model explained 86.6% of the variance in the habitual use of wearable health devices. The goodness-of-fit indices revealed that the proposed model has a desirable fit with the data. Performance expectancy was the core variable explaining the habitual use of wearable devices. The direct effect of the performance expectancy on habitual use of wearable devices was greater (β=.537, P<.001) than that of intention to continue use (β=.439, P<.001), and the total effect estimate of the performance expectancy was 0.909 (P<.001), including the indirect effect (β=.372, P=.03) on habitual use of wearable devices via intention to continue use. Furthermore, performance expectancy was influenced by health motivation (β=.497, P<.001), effort expectancy (β=.558, P<.001), and risk perception (β=.137, P=.02). Perceived vulnerability (β=.562, P<.001) and perceived severity (β=.243, P=.008) contributed to health motivation.

CONCLUSIONS

The results suggest the importance of the users' performance expectations for wearable health devices for the intention of continued use for self-health management and habituation. Based on our results, developers and health care practitioners should find better ways to meet the performance expectations of middle-aged individuals with MetS risk factors. They also should generate device use easier and find a way to encourage users' health motivation, thereby reducing users' effort expectancy and resulting in a reasonable performance expectancy of the wearable health device, to induce users' habitual use behaviors.

Risk Factors for Various Cognitive Function Decline Trajectories in Adults Over 40 Years of Age: A Retrospective Cohort Study

OBJECTIVE

The aims of our study were to identify distinct trajectories of cognitive function using the group-based trajectory model. We also investigate which demographic factors act as risk factors for cognitive decline in each group.

METHODS

The data from the Seoul National University Hospital Healthcare System Gangnam Center, from 2005 to 2019. The number of study subjects was 637. We used a group-based model to identify cognitive function trajectories. Multinomial logistic regression was employed to define risk factors for cognitive function decline.

RESULTS

The cognitive function trajectories among adults over 40 years of age were heterogeneous. We identified four trajectories: high (27.3%), medium (41.0%), low (22.7%), and rapid decline (9.1%). Older age, male, low educational level, bad dietary habits, diabetes mellitus, technical worker, and lower income increased the likelihood of a cognitive function decline.

CONCLUSION

A younger age, a higher educational level, professional worker, good dietary habits, no diabetes mellitus, and no obesity improved cognitive function. A combination of these factors can improve "cognitive reserve" and delay cognitive decline. Interventions to prevent cognitive decline are needed after identification of high-risk groups for cognitive decline.

Exposure to Crude Oil-Related Volatile Organic Compounds Associated with Lung Function Decline in a Longitudinal Panel of Children

BACKGROUND

Children in the affected area were exposed to large amounts of volatile organic compounds (VOCs) from the Hebei Spirit oil spill accident.

OBJECTIVES

We investigated the lung function loss from the exposure to VOCs in a longitudinal panel of 224 children 1, 3, and 5 years after the VOC exposure event.

METHODS

Atmospheric estimated concentration of total VOCs (TVOCs), benzene, toluene, ethylbenzene, and xylene for 4 days immediately after the accident were calculated for each village (n = 83) using a modeling technique. Forced expiratory volume in 1 s (FEV₁) as an indicator of airway status was measured 1, 3, and 5 years after the exposure in 224 children 4~9 years of age at the exposure to the oil spill. Multiple linear regression and linear mixed models were used to evaluate the associations, with adjustment for smoking and second-hand smoke at home.

RESULTS

Among the TVOCs (geometric mean: 1319.5 mg/m³·4 d), xylene (9.4), toluene (8.5), ethylbenzene (5.2), and benzene (2.0) were dominant in the order of air concentration level. In 224 children, percent predicted FEV₁ (ppFEV₁), adjusted for smoking and second-hand smoke at home, was 100.7% after 1 year, 96.2% after 3 years, and 94.6% after 5 years, and the loss over the period was significant (p < 0.0001). After 1 and 3 years, TVOCs, xylene, toluene, and ethylbenzene were significantly associated with ppFEV₁. After 5 years, the associations were not significant. Throughout the 5 years' repeated measurements in the panel, TVOCs, xylene, toluene, and ethylbenzene were significantly associated with ppFEV₁.

CONCLUSIONS

Exposure to VOCs from the oil spill resulted in lung function loss among children, which remained significant up to 5 years after the exposure.

Health-Related Indicators Measured Using Earable Devices: Systematic Review

BACKGROUND

Earable devices are novel, wearable Internet of Things devices that are user-friendly and have potential applications in mobile health care. The position of the ear is advantageous for assessing vital status and detecting diseases through reliable and comfortable sensing devices.

OBJECTIVE

Our study aimed to review the utility of health-related indicators derived from earable devices and propose an improved definition of disease prevention. We also proposed future directions for research on the health care applications of earable devices.

METHODS

A systematic review was conducted of the PubMed, Embase, and Web of Science databases. Keywords were used to identify studies on earable devices published between 2015 and 2020. The earable devices were described in terms of target health outcomes, biomarkers, sensor types and positions, and their utility for disease prevention.

RESULTS

A total of 51 articles met the inclusion criteria and were reviewed, and the frequency of 5 health-related characteristics of earable devices was described. The most frequent target health outcomes were diet-related outcomes (9/51, 18%), brain status (7/51, 14%), and cardiovascular disease (CVD) and central nervous system disease (5/51, 10% each). The most frequent biomarkers were electroencephalography (11/51, 22%), body movements (6/51, 12%), and body temperature (5/51, 10%). As for sensor types and sensor positions, electrical sensors (19/51, 37%) and the ear canal (26/51, 51%) were the most common, respectively. Moreover, the most frequent prevention stages were secondary prevention (35/51, 69%), primary prevention (12/51, 24%), and tertiary prevention (4/51, 8%). Combinations of ≥2 target health outcomes were the most frequent in secondary prevention (8/35, 23%) followed by brain status and CVD (5/35, 14% each) and by central nervous system disease and head injury (4/35, 11% each).

CONCLUSIONS

Earable devices can provide biomarkers for various health outcomes. Brain status, healthy diet status, and CVDs were the most frequently targeted outcomes among the studies. Earable devices were mostly used for secondary prevention via monitoring of health or disease status. The potential utility of earable devices for primary and tertiary prevention needs to be investigated further. Earable devices connected to smartphones or tablets through cloud servers will guarantee user access to personal health information and facilitate comfortable wearing.

Developmental trajectories of tobacco use and risk factors from adolescence to emerging young adulthood: a population-based panel study

Background

Adolescence to young adulthood is a critical developmental period that determines lifelong patterns of tobacco use. We examined the longitudinal trajectories of tobacco use, and risk factors for its use, and explored the association between the trajectories of mobile phone dependency and smoking throughout the life-course among adolescents and young adults.

Methods

Data of 1,723 subjects (853 boys and 870 girls) were obtained from six waves of the Korean Children and Youth Panel Survey (mean age = 13.9–19.9 years). To identify trajectories of smoking and mobile phone dependency, group-based trajectory modelling (GBTM) was conducted. A multinomial logistic regression analysis was performed to identify the characteristics of the trajectory groups.

Results

GBTM identified four distinct smoking trajectories: never smokers (69.1%), persistent light smokers (8.7%), early established smokers (12.0%), and late escalators (10.3%). Successful school adjustment decreased the risk of being an early established smoker (odds ratio [OR] 0.46, 95% confidence interval [CI] 0.27–0.78). The number of days not supervised by a guardian after school was positively associated with the risk of being an early established smoker (OR 1.96, 95% CI 1.23–3.13). Dependency on mobile phones throughout the life-course was positively associated with the risk of being a persistent light smoker (OR 4.04, 95% CI 1.32–12.34) or early established smoker (OR 8.18, 95% CI 4.04–16.56).

Conclusions

Based on the group-based modeling approach, we identified four distinctive smoking trajectories and highlight the long-term effects of mobile phone dependency, from early adolescence to young adulthood, on smoking patterns.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14070-3.

Effect of income level on stroke incidence and the mediated effect of simultaneous diagnosis of metabolic syndrome diseases; a nationwide cohort study in South Korea

BACKGROUND

This study aimed to determine whether a simultaneous diagnosis of main components of metabolic syndrome (MetS) (hypertension, diabetes mellitus, and dyslipidemia) plays a mediator between income level and stroke.

METHODS

We used the National Health Insurance Service National Sample Cohort database from 2006 to 2015. The mediator variables were the number of main MetS components diagnosed simultaneously (two or more/three or more). We used a weighting approach method of causal mediation analysis to apply counterfactual frameworks to the Cox proportional hazards regression model.

RESULTS

A total of 213,526 people were included with 1,690,665.3 person-years of followed up. Compared with the high-income group, the risk of being diagnosed with two or more components of MetS significantly increased in all other income groups [middle-income OR 1.05 (95% CI 1.02-1.08); low-income OR 1.09 (95% CI 1.05-1.12); Medical Aid beneficiaries OR 1.39 (95% CI 1.32-1.47)]. A lower level of income was significantly associated with a higher risk of stroke compared with the high-income group [middle-income HR 1.15 (95% CI 1.07-1.25); low-income HR 1.19 (95% CI 1.10-1.29); Medical Aid beneficiaries HR 1.63 (95% CI 1.48-1.80)]. In the Medical Aid beneficiaries, simultaneous diagnosis of the main metabolic components acted as a significant mediator between income levels and stroke incidence, with 26.6% mediated when diagnosed with two or more diseases and 21.1% when diagnosed with all three.

CONCLUSIONS

Co-diagnosis of MetS components played a significant mediator role between income level and stroke incidence.

Methods of the 2020 (Wave 1) International Tobacco Control (ITC) Korea Survey

This article presents methods used in the 2020 International TC Korea Wave 1 (KRA1) Survey. To date, three cohorts of Korean respondents have participated in the larger ITC Korea Project (cohort 1: 2005-2014, cohort 2: 2016, and cohort 3: 2020-present). The overall objectives of the ITC KRA1 Survey were to examine the use of cigarettes, heated tobacco products (HTPs), e-cigarettes (ECs); whether HTPs might help smokers quit; and the effectiveness of tobacco control policies, such as large graphic warnings, high cigarette taxes, and smoking bans in public places. The KRA1 Survey measures were identical or functionally similar to those of the ITC Japan Survey and, to a lesser extent, those of other ITC countries. Key measures assessed sociodemographic characteristics of respondents; the use of combustible cigarettes, e-cigarettes, and heated tobacco products; and measures assessing policies of the WHO Framework Convention on Tobacco Control, including price and tax (Article 6), smoke-free laws (Article 8), health warnings (Article 11), education, communication and public awareness (Article 12), advertising, promotion, and sponsorship restrictions (Article 13), and support for cessation (Article 14). Adult tobacco and/or nicotine users aged ≥19 years in South Korea were recruited by a commercial survey firm from its online panel. Overall, 4794 respondents completed the KRA1 Survey. The cooperation rate was 97.4% and the response rate was 15.2%. The cohort design permits assessment of transitions in products used among users in South Korea and evaluations of the impact of policies on tobacco and/or nicotine products used and transitions in use.

Gender and tobacco epidemic in South Korea: implications from age-period-cohort analysis and the DPSEEA framework

OBJECTIVES

To understand a 20-year trend of gender-specific smoking prevalence among adults in South Korea.

DESIGN

Age-period-cohort analysis using the intrinsic estimator method was applied to examine the separate contribution of age, period and cohort effect on smoking prevalence. The Driving Force-Pressure-State-Exposure-Effect-Action (DPSEEA) framework was used to explain the observed smoking trends by mapping potential determinants and to address policy implications.

SETTING

General adult population in South Korea.

PARTICIPANTS

34 828 men and 43 632 women who aged 19-78 years, were not currently pregnant and were without a prior diagnosis of cardiovascular disease or cancer.

OUTCOME MEASURES

Gender-specific current smoking prevalence using the 1998-2017 Korea National Health and Nutrition Examination Survey.

RESULTS

Our results showed gender-specific age and birth cohort effects. More specifically, the smoking prevalence peaked at their mid-20s (prevalence rate ratio (PRR): 1.54, 95% CI: 1.49 to 1.59) and cohort born in 1959-1963 (PRR: 1.63, 95% CI: 1.57 to 1.70) and then decreased in men. On the other hand, in women, the smoking prevalence consistently increased until their mid-40s (PRR: 1.53, 95% CI: 1.27 to 1.84) and in recent birth cohort groups (PRR in 1994-1998 cohort: 1.55, 95% CI: 1.13 to 2.13). The period effects declined from 1998-2002 to 2003-2007, following increasing fluctuations in both genders. The smoking-DPSEEA framework showed the absence of policy actions to target female smokers and emphasised a proactive approach that tackles the upstream causes for smoking in women.

CONCLUSIONS

Men and women are clearly in different phases of the smoking epidemic in Korean population, and gender-tailored policies should be implemented.

Inadequate housing and pulmonary tuberculosis: a systematic review

Background

Tuberculosis (TB) is a global health issue that has long threatened and continues to threaten human health. While previous studies are important in the search for a cure for TB, to eradicate the disease it is also crucial to analyze environmental influences. Therefore, this study determined the potential effect of inadequate housing on TB and the magnitude of the effect.

Methods

This is a systematic review of the effects of inadequate housing on TB. Between Jan 1, 2011 and Oct 25, 2020, we searched four electronic databases using the search terms “housing AND tuberculosis” or “housing AND TB”. The target population comprised residents of inadequate housing and the homeless.

Results

We found 26 eligible studies. The distribution of the studies across continents was uneven, and the housing issues of interest seemed to vary depending on the economic level of the country. The eight steps identified in TB development and the consequences thereof were more strongly associated with housing affordability than with housing quality.

Conclusions

This is the first systematic review to identify the effects of inadequate housing on TB and to categorize inadequate-housing-related exposure to TB in terms of affordability and quality. The steps identified in TB development and the consequences thereof had a greater association with housing affordability than with housing quality. Therefore, public health interventions regarding housing affordability could be more diverse, and interventions that support affordable housing for residents of inadequate housing and the homeless should proceed simultaneously to improve housing quality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12879-6.

Classification of Smoking Cessation Apps: Quality Review and Content Analysis

Background

Many people use apps for smoking cessation, and the effectiveness of these apps has been proven in several studies. However, no study has classified these apps and only few studies have analyzed the characteristics of these apps that influence their quality.

Objective

The purpose of this study was to analyze the content and the quality of smoking cessation apps by type and identify the characteristics that affect their overall quality.

Methods

Two app marketplaces (App Store and Google Play) were searched in January 2018, and the search was completed by May 2020. The search terms used were “stop smoking,” “quit smoking,” and “smoking cessation.” The apps were categorized into 3 types (combined, multifunctional, and informational). The tailored guideline of Clinical Practice Guideline for Treating Tobacco Use and Dependence was utilized for evaluating app content (or functions), and the Mobile App Rating Scale (MARS) was used to evaluate the quality. Chi-square test was performed for the general characteristics, and one-way analysis of variance was performed for MARS analysis. To identify the general features of the apps that could be associated with the MARS and content scores, multiple regression analysis was done. All analyses were performed using SAS software (ver. 9.3).

Results

Among 1543 apps, 104 apps met the selection criteria of this study. These 104 apps were categorized as combined type (n=44), functional type (n=31), or informational type (n=29). A large amount of content specified in the guideline was included in the apps, most notably in the combined type, followed by the multifunctional and informational type; the MARS scores followed the same order (3.64, 3.26, and 3.0, respectively). Regression analysis showed that the sector in which the developer was situated and the feedback channel with the developer had a significant impact on both the content and MARS scores. In addition, problematic apps such as those made by unknown developers or copied and single-function apps were shown to have a large market share.

Conclusions

This study is the first to evaluate the content and quality of smoking cessation apps by classification. The combined type had higher-quality content and functionality than other app types. The app developer type and feedback channel with the app developer had a significant impact on the overall quality of the apps. In addition, problematic apps and single-function apps were shown to have a large market share. Our results will contribute to the use and development of better smoking cessation apps after considering the problems identified in this study.

Smoking-related behaviour changes among Korean men after the 2015 tobacco price increase: assessing the implications for the tobacco endgame using a reconstructed retrospective cohort study

OBJECTIVES

To examine the effect of Korea's 2015 tax policy, discuss its effectiveness and limitations and present future directions for tax policy in the context of the tobacco endgame.

DESIGN

A retrospectively reconstructed cohort study.

SETTING

Korea, August 2014-October 2015.

PARTICIPANTS

The study examined 41,605 male smokers aged 19 years and older who participated in the 2015 Korea Community Health Survey.

MEASURES AND ANALYSIS

Binary and multinomial logistic regression was used to assess the impact of the tax policy on smoking-related behaviour. We adjusted for demographic and health-related variables.

RESULTS

Among 41,605 men who were smokers in 2014, 15,499 (35.85%, weighted) reported being affected by the price increase. Of all smokers, 1,772 (3.96%, weighted) reported quitting smoking because of the tobacco price increase. Others reduced their smoking amount (n=9,714, 22.48%, weighted) or made other changes such as switching brands (n=4,013, 9.41%, weighted). An additional 2,401 smokers (5.72%, weighted) quit smoking for reasons other than the tobacco price increase. Compared with those in the highest quintile of household income, the odds that those in the lowest quintile quit smoking due to the price increase were almost twice as high (OR=1.98, 95% CI 1.54 to 2.54).

CONCLUSIONS

Korea's 2015 tobacco price increase affected a significant number of smokers within a year, especially in the lowest income group, inducing some to quit or reduce their smoking amount. However, more smokers quit for reasons independent of the price change. Tax policy can effectively reduce smoking, but needs to be combined with other policies for optimal results.

Spatiotemporal distribution of varicella in the Republic of Korea

Varicella is a highly contagious disease caused by the varicella-zoster virus (VZV). Given its tendency to cluster geographically, spatial analyses may provide a better understanding of the pattern of varicella transmission. We investigated the spatial characteristics of varicella in Korea and the risk factors for varicella at a national level. Using national surveillance and demographic data, we examined the spatial distribution of incidence rates and their spatial autocorrelation and calculated Moran's index. Spatial regression analysis was used to identify sociodemographic predictors of varicella incidence at the district level. An increasing tendency in the annual incidence of varicella was observed over a 12-year period (2006-2018), with a surge in 2017. There was a clear positive spatial autocorrelation of the varicella incidence rate during the surveillance period. During 2006-2014, High-High (HH) clusters were mostly confined to the northeast region and neighboring districts. The spatial error model showed that population density had a negative coefficient and childhood percentage, percentage of children under 12 years of age among the total population, had positive coefficient, whereas vaccine coverage was insignificant. The varicella incidence according to geographic region varied with population density, childhood percentage, suggesting the importance of community-level surveillance and monitoring strategies.

Effect of tobacco outlet density on quit attempts in Korea: a multi-level analysis of the 2015 Korean Community Health Survey

OBJECTIVES

This study aimed to examine whether the regional density of tobacco outlets in Korea was associated with the likelihood of attempting to quit among smokers

METHODS

This study was designed as a secondary data analysis of a cross-sectional study. Data from the 2015 Korean Community Health Survey and tobacco outlet registrations in 17 metropolitan cities and provinces with 254 communities in Korea were used for the analysis. In total, 41,013 current smokers (≥19 years of age) were included. Multi-level logistic regression analysis was conducted to investigate regional differences associated with smokers’ attempts to quit and to evaluate the effects of individual and regional characteristics on quit attempts.

RESULTS

Higher tobacco outlet density was associated with lower odds of attempting to quit. Smokers who resided in districts with the highest tobacco outlet density were 18% less likely to attempt quitting (odds ratio, 0.82; 95% confidence interval, 0.70 to 0.98) than smokers who resided in the regions with the lowest tobacco outlet density (intraclass correlation coefficient, 0.030).

CONCLUSIONS

This study showed that quit attempts were related to community-level factors, such as tobacco outlet density, as well as other individual factors. These findings support the implementation of national policies restricting the number of tobacco outlets within communities or zones and limiting tobacco marketing in tobacco outlets.

The identification of established modifiable mid-life risk factors for cardiovascular disease which contribute to cognitive decline: Korean Longitudinal Study of Aging (KLoSA)

INTRODUCTION

We explored how different chronic diseases, risk factors, and protective factors highly associated with cardiovascular diseases (CVD) are associated with dementia or Mild Cognitive Impairment (MCI) in Korean elders, with a focus on those that manifest in mid-life.

METHODS

A CVD-free cohort (n = 4289) from the Korean Longitudinal Study of Aging was selected to perform Cox mixed-effects proportional hazard regressions. Eighteen control variables with strong associations to CVD were chosen as explanatory variables, and Mini-Mental State Examination (MMSE) score cut-off for dementia and MCI were used as outcome variables.

RESULTS

The statistically significant (P < 0.05) adverse factors that contribute in developing dementia were age (aHR 1.07, 1.05-1.09), Centre for Epidemiological Studies Depression Scale (CESD-10) (aHR 1.17, 1.12-1.23), diagnosis with cerebrovascular disease (aHR 3.73, 1.81-7.66), living with diabetes (aHR 2.30, 1.22-4.35), and living with high blood pressure (HBP) (aHR 2.05, 1.09-3.87). In contrast, the statistically significant protective factors against developing dementia were current alcohol consumption (aHR 0.67, 0.46-0.99), higher educational attainment (aHR 0.36, 0.26-0.56), and regular exercise (aHR 0.37, 0.26-0.51). The factors with a statistically significant adverse association with progression to MCI were age (aHR 1.02, 1.01-1.03) and CESD-10 (aHR 1.17, 1.14-1.19). In contrast, the statistically significant protective factors against developing MCI were BMI (aHR 0.96, 0.94-0.98), higher educational attainment (aHR 0.33, 0.26-0.43), and regular exercise (aHR 0.83, 0.74-0.92).

CONCLUSION

In lieu of the protective factor of MCI and dementia, implementing regular exercise routine well before mid-life and cognitive decline is significant, with adjustments made for those suffering from health conditions, so they can continue exercising despite their morbidity. Further attention in diabetes care and management is needed for patients who already show decline in cognitive ability as it is likely that their MCI impacts their ability to manage their existing chronic conditions, which may adversely affect their cognitive ability furthermore.

Pilot study of fractional microneedling radiofrequency for hidradenitis suppurativa assessed by clinical response and histology

BACKGROUND

Hidradenitis suppurativa (HS) is a devastating chronic inflammatory skin disease with frequent recurrences. Various systemic treatments and procedures have been used but the efficacy of fractional microneedling radiofrequency (FMR) has not been reported.

AIM

To evaluate the clinical and histological efficacy of FMR in the treatment of HS lesions.

METHODS

An 8-week, prospective, split-body, unblinded study was conducted, which enrolled 10 adult patients with mild to moderate HS to receive 3 sessions of FMR treatment biweekly. HS severity was assessed using the number and type of lesions, HS Physician Global Assessment (HS-PGA) and the modified Sartorius score (mSS). Skin biopsies were performed on participants to assess change in inflammation before and after FMR.

RESULTS

Severity of HS was significantly reduced on the FMR-treated side of the body, but not on the control side. Inflammatory HS lesions were significantly reduced after 4 weeks, while HS-PGA and mSS were significantly decreased after 6 weeks. Immunohistochemistry staining showed decreased expression of inflammatory markers including neutrophil elastases, interleukin (IL)-8 and IL-17, tumour necrosis factor-α, transforming growth factor-β1 and matrix metalloproteinases.

CONCLUSION

FMR may be a viable treatment option for mild to moderate HS.

Recent increase in pertussis incidence in South Korea: An age-period-cohort analysis

OBJECTIVES

Pertussis or whooping cough—one of the most contagious diseases—is caused by the Gram-negative bacterium Bordetella pertussis. Despite a high vaccination rate, Korea recently experienced a resurgence of pertussis. This study explores patterns and possible explanations for this resurgence through an age-period-cohort analysis.

METHODS

Using secondary data from the infectious disease portal of the Korea Disease Control and Prevention Agency and the Korea Statistical Information Service of Statistics Korea, this study analyzed the incidence of pertussis in Korea to determine which factors contributed to the recent increase using an age-period-cohort model.

RESULTS

Analysis of the age effect indicated that the age group most vulnerable to pertussis was 0-year to 2-year-olds. Analysis of the period effect showed a sharp increase in the incidence rate after 2016. Analysis of the cohort effect showed a significant decrease in incidence beginning with the 1955 birth cohort, with the risk increasing again with the 2000s birth cohort.

CONCLUSIONS

Previous studies have suggested 3 main possible explanations for our results. First, the increased incidence rate can be attributed to contact rates. Second, the rate of immunity through natural exposure has decreased due to the low number of circulating pathogens, in turn affecting the trend of infection. Lastly, variations in pathogens may have also contributed to the increase in incidence. Given that the most significant increase in incidence was observed among infants younger than 1 year old, sufficient maternal immunity must be prioritized to provide passive immunity to newborns via the placenta.

A comparative study on changes in the use of heat-not-burn tobacco products based on whether apartment buildings have designated non-smoking areas

INTRODUCTION

Since 2016, multi-family housing developments in South Korea can designate public areas such as staircases, elevator, corridors, and underground parking lots as non-smoking areas if at least half of the households residing in the development agree. This study investigated whether there were changes in the use of heat-not-burn tobacco products (HnB) based on whether non-smoking areas were introduced in multi-family housing developments.

METHODS

An online survey of 1200 apartment residents (599 men and 601 women) in seven metropolitan cities in South Korea was conducted from 10 to 18 October 2018.

RESULTS

Among the 1200 people who completed the survey, 493 were smokers (351 men and 142 women), of whom 287 (195 men and 92 women) were currently using HnB. In total, 51.5% (n=148) of the HnB users reported that their smoking frequency inside (n=75) or outside (n=73) the apartment building increased after using HnB, whereas the smoking frequency of 27.5% (n=79) decreased and that of 20.9% (n=6) remained unchanged. Of the HnB users, 25.4% (n=73) were currently living in non-smoking apartments, of whom 39.7% reported that the smoking frequency outside the apartment building increased. On the other hand, of 214 people who did not currently reside in non-smoking apartments, 30.4% reported that the smoking frequency in the apartment increased.

CONCLUSIONS

For smokers to quit smoking, the expansion of non-smoking areas should be accompanied by the facilitation of a smoke-free atmosphere and a smoking-cessation service for smokers.

Harmful alcohol use among mothers of under-five child: findings from the Panel Study on Korean Children

Background

Harmful alcohol use in young mothers as a primary caregiver has a profound impact on their own health and interaction with the child. We studied the epidemiology of harmful alcohol use among Korean mothers and their partners of under-five children.

Methods

We used a longitudinal data of 2,150 Korean mothers of the Panel Study on Korean Children (PSKC). We assessed temporal trend and risk factors for harmful alcohol use in mothers using generalized estimating equation (GEE) model. To estimate the impact of maternal harmful alcohol use on the child, the association between neurodevelopment of the child measured by the Korean-Ages & Stages Questionnaire (K-ASQ) and maternal harmful alcohol use was analyzed using GEE and generalized linear mixed model. We included mother’s age, education, preterm, year of the survey and time-varying covariates (including maternal working status, monthly household income, plan for additional childbirth, psychological stress related with childcare, current smoking, and partner’s harmful alcohol use) in the model.

Results

Mean age of mothers at the baseline was 31.3 years. Annual prevalence of harmful alcohol use increased from 0.7% in the 1st year to 2.6% in the 4th year (P for linear trend < 0.001). Prevalence of harmful alcohol use increased by 48% per year among the mothers (adjusted odds ratio (OR) = 1.48, 95% confidence interval (CI): 1.22, 1.78). Lower education than college or university graduation was associated with higher odds of harmful alcohol use (2.52, 95% CI: 1.43, 4.45). Current smoking (7.44, 95% CI: 3.00, 18.45), harmful use of alcohol of partner (2.66, 95% CI: 1.57, 4.49) were associated with higher risk of harmful alcohol use in mothers. The association between low K-ASQ score and maternal harmful alcohol use was toward positive which did not reach statistical significance.

Conclusions

In a cohort of Korean mothers participating in the PKSC, risk of harmful alcohol use increases over time and is associated with harmful alcohol use of their partners. We suggest an approach targeting both parents can be more effective in controlling the harmful alcohol use of mothers.

Prevalence and predictors of heated tobacco products use among male ever smokers: results from a Korean longitudinal study

Background

This study examined sociodemographic and tobacco-related factors of heated tobacco products (HTPs) use among adult ever smokers in South Korea where the sales of HTPs have been rapidly increasing since their launch in June 2017.

Methods

Before the launch of HTPs in Korea, participants comprised male ever smokers (234 current smokers and 37 quitters) who participated in the Korea National Health and Nutrition Examination Survey from 2015 to 2017 through one-to-one interview survey and agreed to participate in the follow-up surveys through telephone in December 2017. Data were analyzed using logistic regression, to explore sociodemographic and smoking behavior-related factors of HTPs use.

Results

Overall, 10.7% (29/271) of participants responded to using HTPs and 8.1% (22/271) were current HTPs users at the time of the follow-up survey. Multivariate analysis showed that HTPs use is associated with middle age (36 to 49 years old) (aOR = 3.72, CI = 1.16–12.0) (vs. ≥ 50 years), higher income (4Q vs 1Q: aOR = 2.71, CI = 1.16–6.34), and higher educational level (college or higher: aOR = 2.40, CI = 0.87–6.60). Also, vaping experience at baseline was highly associated with HTPs use (aOR = 3.11, CI = 1.22–7.93 for the former experience; aOR = 9.14, CI = 2.34–35.6 for current). However, smoking amount and level of motivation for smoking cessation were not found to be predictors of future HTPs use when limited to current smokers at baseline.

Conclusions

The results showed that vaping experience regardless of current smoking behavior and higher socioeconomic status were found to be associated with subsequent HTPs use among ever smokers. Further studies are required to explore whether this association is causal.

Protective effect of predator species richness on human hantavirus infection incidence

Are predators of rodents beneficial for public health? This question focuses on whether predators regulate the spillover transmission of rodent-borne diseases. No clear answer has emerged because of the complex linkages across multiple trophic levels and the lack of accessible data. Although previous empirical findings have suggested ecological mechanisms, such as resource partitioning, which implies protective effects from predator species richness, epidemiological evidence is needed to bolster these arguments. Thus, we investigated the association between predator species richness and incidence of rodent-borne haemorrhagic fever with renal syndrome in the human population using district-level longitudinal data of 13 years for South Korea. With the exception of districts with low species richness, we found a significant negative association between the incidence of haemorrhagic fever with renal syndrome and the species richness of both avian and mammalian predators; the trends for both predator types were similar. Thus, biodiversity conservation may benefit public health.

Longitudinal transitions of cigarettes and electronic nicotine delivery systems among adolescents: Construction of a retrospective cohort using recall data from a cross-sectional sample

INTRODUCTION

A major concern regarding non-cigarette tobacco or nicotine products (NCTNPs) is whether they facilitate or mitigate overall tobacco or nicotine use. We examined longitudinal transitions of cigarettes and electronic nicotine delivery systems (ENDS) by constructing a retrospective cohort based on the recall data of a cross-sectional sample.

METHODS

Using the Korea Youth Risk Behavior Survey, we constructed crosssectional data of 59576 adolescents into retrospective cohort data. Participants were categorized into 4 mutually exclusive tobacco or nicotine use states. We used a multistate Markov model to identify transitions between the states to calculate transition intensity ratios (TIRs), and examined the current use of tobacco or nicotine products to assess both gateway effects to cigarettes, and whether ENDS use helps adolescents quit cigarette smoking.

RESULTS

Compared with never use, use of ENDS was associated with an increased risk of initiation of cigarette use (TIR=6.8; 95% CI: 4.5-10.2). The risk of transitioning from cigarette ever use to ENDS, compared with never use to ENDS, was even more pronounced (TIR=44.1; 95% CI: 34.1-56.9). The prevalence of current cigarette smoking was higher among those who started ENDS then cigarettes, compared to those who began cigarette use without experimenting with ENDS (43.1% vs 35.8%). Moreover, 27.8% (95% CI: 23.6-32.0%) of adolescents who experimented first with cigarettes then moved to ENDS were current users of cigarettes, and 46.4% (95% CI: 42.1-51.1%) of these adolescents were current users of both cigarettes and ENDS.

CONCLUSIONS

Based on the recall data of a cross-sectional sample, we demonstrate that ENDS experimentation increases the likelihood of cigarette smoking initiation. A significant proportion of these adolescents continue to use cigarettes. Moreover, those who experimented with cigarettes then ENDS also continue smoking cigarettes or both cigarettes and ENDS. We suggest comprehensive tobacco control policies for all tobacco/nicotine products and monitoring the timing of NCTNP initiation in cross-sectional surveys.

Interpretation of the Basic and Effective Reproduction Number

In epidemiology, the basic reproduction number (R₀) is a term that describes the expected number of infections generated by 1 case in a susceptible population. At the beginning of the coronavirus disease 2019 (COVID-19) pandemic, R₀ was frequently referenced by the public health community and the wider public. However, this metric is often misused or misinterpreted. Moreover, the complexity of the process of estimating R₀ has caused difficulties for a substantial number of researchers. In this article, in order to increase the accessibility of this concept, we address several misconceptions related to the threshold characteristics of R₀ and the effective reproduction number (R_t). Moreover, the appropriate interpretation of the metrics is discussed. R₀ should be considered as a population-averaged value that pools the contact structure according to a stochastic transmission process. Furthermore, it is necessary to understand the unavoidable time lag for R_t due to the incubation period of the disease.

Association of COVID-19 with skin diseases and relevant biologics: a cross-sectional study using nationwide claim data in South Korea

Background

As the coronavirus disease 2019 (COVID‐19) pandemic has spread, information about COVID‐19 and skin disease or related biologics is still lacking.

Objectives

To identify the association between COVID‐19 and skin diseases or biologics.

Methods

A nationwide claim dataset relevant to COVID‐19 in South Korea was analysed. This dataset included insurance claim data before and during COVID‐19 treatment and clinical outcomes. Claim data related to skin diseases and relevant biologics were analysed to determine the association of COVID‐19 with skin diseases and relevant biologics.

Results

The dataset contained a total of 234 427 individuals (111 947 male and 122 480 female) who underwent COVID‐19 testing. Of them, 7590 (3·2%) were confirmed as having COVID‐19, and 227 (3·0%) confirmed patients died. Among various skin diseases and biologics, no significant increase in the presence of specific skin diseases or exposure to biologics was observed in the COVID‐19‐positive group, even after adjusting for or matching covariates. The presence of skin diseases and exposure to biologics also did not seem to affect clinical outcomes including mortality.

Conclusions

Underlying skin diseases did not appear to increase susceptibility to COVID‐19 or mortality from COVID‐19. Considering the risks and benefits, biologics for dermatological conditions might be continuously used during the COVID‐19 pandemic.

Individual and joint association of adulthood experiences and parental or teacher smoking with adolescent cigarette smoking

INTRODUCTION

One limitation of the minimum legal age (MLA) law, the primary strategy for curbing youth smoking, is the rite-of-passage effect. Adulthood experiences and the behavior of surrounding adults help build ‘adult identity’ among adolescents. We examined the individual association of adulthood experience and joint association with significant adults who smoke with adolescent cigarette smoking.

METHODS

A nationally representative cross-sectional sample of 138542 South Korean adolescents aged 12–18 years (mean: 15 years) from the 2014 and 2015 Korea Youth Risk Behavior Survey was used. Adulthood markers used were tall stature, precocious sexual development, independent living, and job experience. Parents and teachers were considered significant adults. Logistic regression analyses and relative risk due to interaction (RERI) calculations were conducted.

RESULTS

Tall stature (OR=1.19; 95% CI: 1.08–1.31), precocious sexual development (OR=1.51; 95% CI: 1.36–1.69), independent living (OR=1.24; 95% CI: 1.08– 1.43), and job experience (OR=4.38; 95% CI: 4.14–4.64) were associated with cigarette smoking among study participants. Statistically significant additive interactions were found for parental smoking and job experience (RERI=0.41; 95% CI: 0.06–0.76), teacher smoking and precocious development (RERI=0.71; 95% CI: 0.28–1.15), teacher smoking and independent living (RERI=0.68; 95% CI: 0.11–1.24), teacher smoking, and job experience (RERI=2.12; 95% CI: 1.66– 2.58).

CONCLUSIONS

The association between adulthood experience and adolescent cigarette smoking suggests the rite-of-passage effect, which may be strengthened by the MLA law. Raising the MLA to an age much higher than the normative age of adulthood initiation is required. Additionally, targeted intervention for adolescents with both adulthood experience and exposure close to adult smoking are required to curb youth smoking.

The Evolving Policy Debate on Border Closure in Korea

OBJECTIVES

In this paper, we aimed to investigate the evolving debate over border closure in Korea during the coronavirus disease 2019 (COVID-19) pandemic, to address the main themes associated with border closure, and to discuss the factors that need to be considered when making such decisions.

METHODS

We collated and reviewed previously conducted review studies on border closures during infectious disease outbreaks to derive relevant themes and factors.

RESULTS

According to our systematic review on border closures and travel restrictions, the effects of such containment efforts are limited. We suggest considering the following factors when determining whether to impose border closure measures: (1) disease characteristics, (2) timeliness of implementation, (3) transmission delay and the basic reproduction number, (4) globalization and pandemics, and (5) social and economic costs.

CONCLUSIONS

Our assessment indicates that the effects of border closures are at best temporary and limited. Alternative measures must be contemplated and implemented to suppress the spread of COVID-19 in particular and infectious diseases more broadly.

Setting the policy agenda for graphic health warning labels: An analysis of online news media coverage in South Korea, 2016

INTRODUCTION

In South Korea, a bill requesting the implementation of graphic health warning labels (GHWLs) on tobacco products was adopted at the Assembly Plenary Session on 29 May 2015, and the law was implemented on 23 December 2016. During the period, a plan of the technical details of GHWLs, such as the making of graphic warnings, was examined by the Regulatory Reform Committee (RRC). This study aims to investigate what the media reported over that period and whether the RRC's policy decisions changed.

METHODS

We conducted a content analysis of online media reports from the first legislative examination (22 April 2016) to the re-examination (13 May 2016). We coded 150 news reports according to two types (news and opinions) and three slants in terms of being in favor of or opposed to the initially government's implementation plan of GHWLs: positive, negative, and neutral.

RESULTS

At the first legislative examination, some committee members recommended placing pictorial warnings at the bottom of a cigarette pack as opposed to the plan. Initially, the media reported the results of the committee decisions neutrally. However, over time, positive news and opinions on tobacco control policy and support for positioning the GHWLs at the top of packages increased before the committee carried out the re-examination. Only 15 (10.0%) news reports adopted a negative slant, while the reports with positive (n=101; 67.3%) and neutral slants (n=34; 22.7%) comprised the majority. At the re-examination, the committee withdrew their earlier recommendation to position the GHWLs at the bottom of cigarette packs, finally deciding that the pictorial warnings should be located at the top of the packs, as per the original government's plan.

CONCLUSIONS

The friendly media coverage of the tobacco control policy suggests that the media would be a major factor in the policymakers' decision. Because the media play an important role in defining social issues in the policy-decision process, garnering support from the media is important in the tobacco control legislative process.

Impact of Age and Comorbidity on the Short-Term Surgical Outcome after Laparoscopy-Assisted Distal Gastrectomy for Adenocarcinoma

The aim of this study was to determine whether age and comorbidity are valuable risk factors of the short-term surgical outcome after laparoscopy-assisted distal gastrectomy (LADG) in patients with adenocarcinoma. A series of 387 patients who underwent LADG at three university hospitals between March 2006 and December 2010 were retrospectively studied. To compare the short-term surgical outcomes of LADG of elderly patients with those of younger patients, patients were categorized into an elderly group (older than 70 years of age) and a younger group (70 years of age or younger). For another comparative analysis to identify risk factors of postoperative complications after LADG, patients were categorized into two groups: those with complications and those without complications. With the exception of sex ratio and comorbidity rate, two age groups were nonsignificantly different in terms of demographic, operative, pathologic, and short-term surgical outcome data. Our data support the safety and feasibility of LADG in elderly patients. However, our data show that comorbidity is an important predictor of postoperative systemic complications after LADG. Patients with an age-adjusted Charlson comorbidity index (CCI) of 3 or greater were found to be at a greater risk of developing systemic complications, which suggests that age-adjusted CCI is a useful predictor of systemic complications after LADG and that it could be used routinely for the perioperative care of aged patients with comorbidity. We recommend age-adjusted CCI be used in comparative clinical research studies on the surgical outcomes across surgeons and hospitals.

The association between new graphic health warning labels on tobacco products and attitudes toward smoking among south Korean adolescents: a national cross-sectional study

Background

Graphic health warning labels (GHWLs) on tobacco products are more effective than text warnings for communicating the risk of smoking. The implementation of GHWLs can prevent adolescents from initiating smoking. Therefore, this study examined the association between GHWLs newly implemented on December 23, 2016, in South Korea and attitudes toward smoking among adolescents.

Methods

This post-implementation cross-sectional analysis examined the responses of 62,276 students (31,624 boys and 30,652 girls) who participated in the 2017 Web-based Korean Youth Risk Behavior Survey, which was completed anonymously as a self-administered questionnaire by middle and high school students. Multinomial logistic regression was applied to explore the attitudes toward smoking among the youth (13–18 years old) who have been exposed to GHWLs in order to identify relationship of exposure to the GHWLs with smoking initiation and awareness of the danger of smoking.

Results

Six months after implementation, 69.4% of adolescents reported having been exposed to GHWLs in the previous 30 days. Among those exposed to GHWLs both boys and girls in grade 7 were significantly more likely than grade 12 high school students to decide not to start smoking (boys: AOR = 3.96, 95% CI 3.31–4.75, p < 0.001; girls: AOR = 2.76, 95% CI 2.32–3.30, p < 0.001) and to think that smoking was dangerous to their health (boys: AOR = 3.01, 95% CI 2.52–3.58, p < 0.001; girls: AOR = 2.42, 95% CI 2.03–3.88, p < 0.001) after seeing GHWLs. These associations were greater for adolescents who had experienced smoking-prevention education or had been exposed to anti-tobacco advertisements. However, those who smoked, used e-cigarettes, or experienced secondhand smoking were significantly less likely to decide not to smoke and to view smoking as dangerous.

Conclusions

To maintain the perception of the harm of tobacco from childhood through adolescence, the government should implement both comprehensive tobacco controls, including smoking-prevention education in schools, and measures to encourage a smoke-free environment in homes.

Three-year outcome of rapid HIV testing at public health centers in Seoul, Republic of Korea: a short report

Before 2014, the only test used for anonymous voluntary human immunodeficiency virus (HIV) screening at public health centers (PHCs) in the Republic of Korea was an enzyme-linked immunosorbent assay (ELISA), which takes around 3 days to obtain results. In 2014, to encourage voluntary anonymous HIV screening tests, the Seoul Metropolitan Government adopted a rapid HIV screening test at PHCs. The rapid HIV screening test was introduced at four PHCs in 2014 and all 25 PHCs after 2015. We compared the numbers of HIV screening tests and confirmed positive individuals before and after introduction of the rapid HIV screening test. In 2012-2013, before the introduction of rapid HIV screening test, an average of 330 HIV screening tests were performed monthly (355 in 2012 and 305 in 2013) and 69 individuals were confirmed to have HIV in 2012 and 93 in 2013. After the introduction of the rapid HIV screening test, anonymous voluntary HIV screening increased to a monthly average of 447 tests in 2014, 2099 in 2015, and 2409 in 2016. These identified 38 new cases in 2014, 116 in 2015, and 143 in 2016. Adoption of the rapid HIV screening test has increased the number of HIV screening tests and confirmed cases.

Determinants of the persistence of malaria in Rwanda

Background

Malaria has a considerable impact on the health of the populations of developing countries; indeed, the entire population of Rwanda is at risk of contracting the disease. Although various interventions to control malaria have been implemented in Rwanda, the incidence of malaria has increased since 2012. There is an interest in understanding factors driving its persistence in Rwanda. This study aims at evaluating the effect of socio-economic and environmental factors, seasonality and the use of insecticide-treated mosquito nets (ITNs) on malaria persistence in Rwanda.

Methods

This study analysed data from the 2014–2015 Rwanda Demographic and Health Survey of 11,202 household’s members composed of children under the age of 5 and women aged between 15 and 49. Bivariate analysis was performed between the outcome and each covariate including wealth, altitude, education level, place of residence, and use of ITNs generating percentages. Chi square test was performed to compare malaria negatives and positives on each covariate. Significant variables were subjected to logistic regression analysis to evaluate factors that are significantly associated with malaria at P < 0.05. The analysis was performed in R x64 3.6 and QGIS3.6 was used to map geographical distribution of malaria cases.

Results

The lowest wealth category was associated with the incidence of malaria [AOR] = 1.54, 95% CI (1.78–2.03). Having a place of residence < 1700 m above sea level (asl) and non-use of ITNs were significantly associated with the incidence of malaria (adjusted odds ratio [AOR] = 2.93, 95% confidence interval [95% CI] 1.94–4.42 and [AOR] = 1.29, 95% C.I (1.03–1.60), respectively). Season and type of residence were not significantly associated with malaria prevalence while women had lower risk of contracting malaria than children.

Conclusion

Increased malaria prevalence was associated with lower income, non-compliance with bed-net usage and living below 1700 m of altitude. In addition to current malaria control strategies, potential interventions in individuals with lower income and areas at low altitudes should be taken into consideration when formulating malaria-control strategies, Also use of ITNs to control the spread of malaria should be emphasized.

Analysis of the legislative process related to the implementation of graphic health warning labels on tobacco products in South Korea

INTRODUCTION

Well-designed health warnings on tobacco packaging enhance cost-effectively public awareness of the risks of using tobacco products. However, many countries have experienced difficulties in implementing pictorial warnings. The purpose of this study is to present the topics that arose during the legislative process that preceded implementation of graphic health warning labels (GHWLs) on tobacco products in South Korea, and discuss the outcomes.

METHODS

We used qualitative content analysis to analyze lawmakers' statements, and those of committee members in meetings that preceded the drafting of the legislative document pertaining to GHWLs in South Korea.

RESULTS

In discussions surrounding the adoption of the GHWLs, the main point of contention was the level of disgust induced by pictorial warnings. When discussing how warnings should be inscribed on packaging after adoption of GHWLs, lawmakers disagreed regarding the physical position of the warnings. Because of continuous objections raised by some lawmakers, implementation of GHWLs was delayed, and, when actually introduced, the warnings were toned down. Some lawmakers communicated with tobacco companies; thus the companies participated in the legislative process in South Korea.

CONCLUSIONS

To prevent tobacco companies from negatively influencing tobacco control efforts, it is essential that all communications with such companies be publicly disclosed and that the tobacco industry be prohibited from contacting lawmakers involved in the legislative process of tobacco control.

Convenience store visitors recall cigarette advertisements even if they do not purchase cigarettes

Background

This study examined the extent to which visitors to convenience stores remember the cigarette advertisements they encounter in these stores and investigated the relationships between how advertisements are recalled and attitudes toward them.

Methods

Exit surveys of 1007 visitors to three convenience stores located in Seoul, Korea, were conducted between 25 November 2015 and 7 December 2015.

Results

Of the respondents, 23.4% (n = 236) freely recalled the cigarette advertisement in the store just visited. However, the percentage of participants who correctly recalled the advertisement increased to 55.2% (n = 556) after we presented them with a card showing options for the advertisement (i.e. a cued recall task). Regardless of sex or purchasing cigarettes, free recall performance was significantly associated with age, number of weekly visits to the convenience store and current smoking status. In addition, free recall increased with having a positive attitude toward cigarette advertisements.

Conclusions

Repeated visits to convenience stores may continue to expose individuals to cigarettes and their advertisements; such exposure may subconsciously affect recall of the advertisements and maintenance of a positive attitude toward cigarette advertisements. Therefore, to denormalize smoking in society, cigarette advertising and displays at points of sale including convenience stores, should be banned.