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This study investigated the nitrate dual isotopic compositions (δ 15 N NO3 and δ 18 O NO3 ) of water samples to trace nitrate sources in Lake Sihwa, which encompasses various land-use types (e.g., urban, industry, wetland, and agriculture). The biogeochemical interactions of anthropogenic nitrogen sources (e.g., soil, road dust, and septic water) were also evaluated through multiple pathways from terrestrial boundaries to the water column. Based on increased concentrations of dissolved total nitrogen (DTN; 3.1 ± 1.6 mg/L) after typhoon, the variation of element stoichiometry (N:P:Si) in this system shifted to the relatively N-rich conditions (DIN/DIP; 14.1 ± 8.1, DIN/DSi; 1.4 ± 1.8), potentially triggering the occurrence of harmful algal blooms. Furthermore, discriminative isotopic compositions (δ 15 N NO3 ; 4.0 ± 2.1 ‰, δ 18 O NO3 ; 6.1 ± 4.3 ‰) after the typhoon suggested the increased DTN input of anthropogenic origins within Lake Sihwa would be mainly transported from urban sources (76 ± 9 %). Consequently, the isotopic-based approach may be useful for effective water quality management under increased anthropogenic activities near aquatic systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Weight gain in adults is associated with an increased risk of obesity-related diseases and high healthcare costs. However, there have been limited studies on weight gain in Asians. This study investigated the prevalence, comorbidities, and associated factors of weight gain in the Korean population., Methods: This is a cross-sectional study of Korean adults aged 19-64 years who participated in the Korea National Health and Nutritional Examination Survey 2016-2019. We used data from 15,514 adults (subjects 1) to analyze the prevalence of weight gain. Finally, after excluding adults with suspicious debilitating conditions among them, 11,477 adults (subjects 2) were used to analyze comorbidities and associated factors. Weight changes and lifestyle factors were assessed using a self-report questionnaire. We analyzed odds ratios and 95% confidence intervals using multivariable logistic regression analysis to examine factors associated with weight gain., Results: The overall prevalence of weight gain was 25.7% in men and 31.3% in women and decreased significantly with age in both sexes. Weight gain of ≥ 6 kg was evident in 10.5% of men and 9.8% of women and was more pronounced with a higher baseline body mass index (BMI). Most metabolic comorbidities worsened the greater the weight gain. Young age was the strongest associated factor for weight gain. Other factors associated with weight gain were being unmarried, blue-collar job, lower income, and alcohol consumption in men; being married in women; smoking and skipping breakfast in both sexes., Conclusion: Weight gain was much more pronounced in younger adults and at a higher baseline BMI in both sexes. Public education and health policies to prevent unnecessary weight gain should be strengthened by considering the associated harmful factors in Korean adults., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2023 The Korean Academy of Medical Sciences.)

A new town is strategically built within a short period compared to naturally developed cities. It is considered an appropriate study area for analyzing the urban climate problems such as surface urban heat islands (SUHIs) that is differently generated according to urban planning and development. In this study, we suggest comprehensive method for determining and comparing changes in surface UHI distribution during 1989-2048 in two new towns with different urban planning. First, a substantial increase in built-up areas was observed from 1989 (< 5%) to 2018 (> 40%) in both new towns. However, SUHI phenomenon-increasing patterns were different of about 12.25% depending on urban planning and urban morphology. Results also showed the importance of vertical and horizontal structures which can have a great influence on SUHI intensity and accordingly, the difference in SUHI distribution between two new towns was confirmed. Moreover, without effective mitigation, the built-up area in both new towns is estimated to increase to approximately 60%, and the SUHI intensity in most areas to increase by 4 °C in 2048. In addition, the spread and intensification of the SUHI phenomenon are predicted to be greater due to the characteristics of the building structure and the active urban expansion. Thus, these results combined with architectural assessment models can improve the understanding of thermal environmental impacts of urbanization and provide directions for sustainable urban development and renovation., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Background: Obesity affects health-related quality of life (QoL); however, their relationship among elderly Asians is not well known., Aims: Relationship of domain-specific QoL with body mass index (BMI) and waist circumference and the sex differences were investigated using a nationally representative sample of elderly Korean population., Methods: In the Korea National Health and Nutrition Examination Survey phase VII (2016-2018), 3659 adults aged ≥ 65 years (1551 men and 2108 women) participated. BMI and waist circumference were classified according to Asian- and Korean-specific criteria. QoL was evaluated using the European Quality of Life Scale-Five Dimensions (EQ-5D). Multivariable logistic regressions were used to examine the relationship of QoL with BMI and waist circumference., Results: Men with BMI < 18.5 kg/m 2 and ≥ 25.0 kg/m 2 had a significant association with poor QoL in mobility and self-care, but no relationship was found with the other domains. Women with BMI ≥ 25.0 kg/m 2 had poor QoL in mobility and self-care, and those with BMI ≥ 30.0 kg/m 2 had poor QoL in usual activities and pain/discomfort. There was no significant association with anxiety/depression. Both elderly men and women with abdominal obesity had a significant association with poor QoL in mobility, self-care, usual activities, and pain/discomfort; however, there was no significant relationship with waist circumference and anxiety/depression., Conclusions: The association between QoL and BMI was different according to sex and the domains of QoL. Domain-specific QoL should be considered in the management of body weight of the elderly., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Despite receiving a considerable amount of attention in the past, quantitative and systematic estimation of the source contributions for different organic carbons (OCs) in complex river systems is still challenging. In this study, we tested an integrated framework using field data of bulk elements and lipid biomarkers and hydrological modeling (hydrological simulation program FORTRAN, HSPF) for the quantitative estimation of OC loads along different land-use types of a watershed (Geumho River watershed in South Korea). Based on the specific source assignments identified from the lipid biomarker patterns in particulate organic carbon (POC) such as short/long chains of alkanes, fatty acids and alcohols, and coprostanol/cholesterol, spatial variations of the diagnostic lipids could be used as an indicator to discriminate between the contributions of natural (algae, bacteria, and terrestrial plants) and anthropogenic sources (fecal). Based on the integration of HSPF modeling, it was also found that various POC loads might be partially controlled by different water discharges within watersheds. With the increase in POC fluxes, the increase in fecal loads was also noticed, as reflected by the predominant lipid (especially coprostanol normalized by water discharges). As a straightforward approach, we developed a set of indices including fecal index-1, ratios of coprostanol, fatty acids, and alkanes, which strengthened the sensitivity for fecal contamination. Compared with the conventional HSPF results, the variations of these proposed indices were more influenced by the broadened watershed extents with increasing downstream distance, which provided a more accurate estimation of the quantitative contributions of POC loadings in the complex river system., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Dyslipidemia is considered an independent health risk factor of cardiovascular disease (CVD), a leading cause of mortality in older adults. Despite its importance, there have been few reports on the association between lipoprotein cholesterol and future CVD and cardiovascular (CV) mortality among elderly Asians aged ≥ 65 years. This study investigated the association between lipoprotein cholesterol and future CVD and CV mortality in an elderly Korean population using a large nationwide sample., Methods: From the cohort database of the Korean National Health Insurance Service, 62,604 adults aged ≥ 65 years (32,584 men and 30,020 women) were included. High-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels were categorized by quartiles. Cox proportional hazard models and linear regression analyses were used to assess the association between the quartiles of lipoprotein cholesterol and future CV events or mortality., Results: The mean follow-up period was 3.3 years. The incidence rates of ischemic heart disease and ischemic brain disease were 0.97 and 0.61 per 1,000 person-years, respectively, and the mortality rates from these diseases were 0.22 and 0.34 per 1,000 person-years, respectively. In a completely adjusted model, high HDL-C and LDL-C levels were not associated with total CV events and CVD mortality. However, high LDL-C levels were significantly associated with a lower incidence of ischemic brain disease. Furthermore, diabetic patients with high LDL-C levels were more likely to have higher CV mortality, whereas non-smokers with high LDL-C levels were less likely to be at risk of CV events., Conclusions: Neither high LDL-C nor HDL-C levels were significantly associated with future CV mortality in older adults aged ≥ 65 years. High LDL-C levels do not seem to be a risk factor for CVD in elderly individuals, and further studies are required.

Heated tobacco products (HTPs) have been widely used in Korea since their introduction in 2017. In this study, we investigated the perceptions of their relative harmfulness and smoking cessation effects. We performed an online survey in 7000 Koreans in 2018 (2300 males and 4700 females aged 20-69 years) by matching their age, sex, and provincial distribution. To investigate the factors causing HTPs to be perceived as less harmful than combustible cigarettes (CCs) and helpful for smoking cessation, we used multivariable logistic regression analyses. HTPs were less harmful than CCs in 16.8% of participants, particularly among HTP-only users and dual and triple users of HTPs, electronic cigarettes (ECs), or CCs than among CC-only users, those who were aged ≤ 34 years, males, and those with higher incomes. HTPs were reportedly helpful for smoking cessation in 11.2% of participants. Similar perceptions were more likely among HTP-only users, as well as dual and triple users than among CC-only users and adults with higher education/incomes. Although Korean adults generally had negative perceptions of the harmfulness and smoking cessation effects of HTPs compared with CCs, dual and triple users were more likely to have positive perceptions. Monitoring the use of multiple tobacco products and HTPs is a new challenge for Korean policymakers.

This study aimed to examine the association between disability and cardiovascular (CV) disease incidence and mortality in Korea longitudinally, using a national representative sample. We used the National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS) database, which includes information on the disability of the National Screening Program participants such as severity and type of disability, which were obtained from the Korean National Disability Registry. Cox proportional hazard models were used to evaluate the association between disability and CV disease incidence and mortality. We constructed four models with different levels of adjustment, in which Model 3 was a fully adjusted model. This study included 514,679 participants, and 7,317 CV deaths were reported within a mean follow up of 10.8 ± 3.9 years (maximum, 13.9 years). For 5,572,130 person-year (PY) follow-up, the CV mortality rate was 1.313 per 1,000 PY. In Models 1 and 2, CV disease incidence was significantly higher in participants with disability than in those without disability. In Model 3, the incidence was higher only among participants aged 50-64 years and severe disabled participants aged <50 years. CV mortality was significantly higher in participants with disability than in those without disability in all Models, and the mortality increased in both sexes in Models 1 and 2 but only increased in men in Model 3. Similar results were observed in the subgroup analysis of health behavior and chronic diseases. People with disability showed higher CV disease incidence and mortality than those without disability, regardless of the type of disability or risk factors for CV disease., Competing Interests: The authors have declared that no competing interests exist.

The OECD has proposed a new, validated test guideline with the stimulated weanling male Hershberger assay to avoid the surgical castration step. In the present study, we assessed the relevance and reliability of the stimulated weanling Hershberger assay in four stages. All chemicals except for testosterone propionate (TP) were orally administered to sexually immature male rats of 22 days old for 10 days. The weights of four mandatory accessory sex organs, two additional reproductive tissues and optional systemic organs were evaluated. At the first two stages, TP, as reference androgen, significantly increased the weights of epididymides and accessory sex organs (ASO) at 1.0 mg kg(-1) and flutamide (FLU), as a positive anti-androgen control, decreased the TP-stimulated organ weights at 3.0 mg kg(-1). At stage 3, trenbolone (40 mg kg(-1)), an anabolic steroid, significantly increased ASO weights, and weak anti-androgens (DDE and linuron) decreased the TP-stimulated ASO weights at each high dose. The above results were confirmed in a blind test with coded substances provided by OECD. Compared with results from our previous castrated male assay, the intact weanling version is less sensitive than the castrated male version, in terms of a smaller response at the reference dose of TP or FLU. However, this study suggests that the stimulated weanling Hershberger assay can detect the effects of both potent and weak anti-androgens on androgen-producing and androgen-dependent tissues., (2010 John Wiley & Sons, Ltd.)