Beneficial impacts of residential greenness on sleep deprivation in adults aged 19 or older living in South Korea: A nationwide community health survey in 2011-2018.

BACKGROUND: Evidence of the relationship between greenness and sleep is limited, and, given the worsening sleep insufficiency worldwide, this relationship needs elucidation. In this study, we investigated the association of greenness with sleep deprivation using nationwide survey data. METHODS: This study included 1,727,273 participants in the Korea Community Health Survey who resided in all 229 districts of South Korea from 2011 to 2018. Sleep deprivation variables were defined as strong deprivation or mild deprivation, based on average daily sleep duration of <5 or 5-6 h, respectively. District-specific annual average of satellite-derived enhanced vegetation index (EVI) was used as a green space exposure. A logistic regression with complex survey weights was used to estimate the association between greenness and sleep deprivation, and it was further examined by sex, age group, educational status, income level, and population density. The regression analysis was performed annually, and the annual estimates were pooled by a combined data analysis. RESULTS: A higher level of greenness was associated (odds ratio [95 % confidence interval]) with strong and mild sleep deprivation (0.96 [0.93-0.99] and 0.96 [0.95-0.97]), respectively, and males and the younger age group (<65 years) showed a more prominent association with greenness than in females and the elderly group (65 years or older). In addition, only high-population-density areas showed evident associations of greenness with both strong and mild sleep deprivation. CONCLUSIONS: This large population-based study provides important epidemiological evidence for improving sleep quantity through an increase in greenness exposure and supports policymakers in establishing strategies for urban planning.

Effects of urbanization on vulnerability to heat-related mortality in urban and rural areas in South Korea: a nationwide district-level time-series study.

BACKGROUND: Although urbanization is often an important topic in climate change studies, the complex effect of urbanization on heat vulnerability in urban and rural areas has rarely been studied. We investigated the disparate effects of urbanization on heat vulnerability in urban and rural areas, using nationwide data. METHODS: We collected daily weather data for all 229 administrative districts in South Korea (2011-17). Population density was applied as an urbanization indicator. We calculated the heat-mortality risk using a distributed lag nonlinear model and analysed the relationship with population density. We also examined district characteristics that can be related to the spatial heterogeneity in heat-mortality risk. RESULTS: We found a U-shaped association between population density and heat-mortality risk, with the highest risk for rural populations; in urban areas, risk increases with increasing population density. Higher heat-mortality risk was associated with a lower number of hospital beds per person and higher percentage of people requiring recuperation. The association between hospital beds and heat-mortality risk was prominent in high-density urban areas, whereas the association between the percentage of people requiring recuperation and heat-mortality risk was pronounced in rural areas. CONCLUSIONS: Our findings indicate that the association between population density and heat-mortality risk is different in urban and rural areas, and that district characteristics related to heat-mortality risk also differ by urbanicity. These results can contribute to understanding the complex role of urbanization on heat vulnerability and can provide evidence to policy makers for prioritizing resources.

Roles of urban heat anomaly and land-use/land-cover on the heat-related mortality in the national capital region of South Korea: A multi-districts time-series study.

The urban heat anomaly has been suggested as a representative risk factor for human health in metropolitan areas, but few studies have measured a quantitative increase in risk due to the urban heat anomaly on heat-related mortality in the summer season or assessed the role of various types of land-use/land-cover (LULC), which may contribute to the urban heat anomaly. In this study, we evaluated the association between the urban heat anomaly and heat-related mortality risk in the summer and the potential roles of multiple types of LULC indicators. We used district-level time-series and cadastral data from 51 urban districts in the national capital region of South Korea. We applied a two-stage analysis. In the first stage, we estimated the district-specific heat-related mortality risk by using a distributed lag non-linear model. In the second stage, we used a meta-analysis to pool the estimates across all districts and calculate the association between the urban heat anomaly/LULC indicators and heat-related mortality risk. We found that the higher urban heat anomaly was related to lower vegetation and higher urban surface indicators, and the urban heat anomaly was positively associated with the heat-related mortality risk. The association between the urban heat anomaly and the heat-related mortality risk was more pronounced in the elderly (age ≥ 65 years) and female population than in the non-elderly and male population. We also found that the LULC indicators affected the heat-related mortality only through the urban heat anomaly. Our findings indicate that urban areas may be more vulnerable to heat-related mortality risk as determined by the urban heat anomaly. These results suggest a need for urban heat mitigation strategies such as increased vegetation or surface albedo to help reduce heat-related mortality risk.

Heatwave-Related Mortality Risk and the Risk-Based Definition of Heat Wave in South Korea: A Nationwide Time-Series Study for 2011-2017.

Studies on the pattern of heatwave mortality using nationwide data that include rural areas are limited. This study aimed to assess the risk of heatwave-related mortality and evaluate the health risk-based definition of heatwave. We collected data on daily temperature and mortality from 229 districts in South Korea in 2011-2017. District-specific heatwave-related mortality risks were calculated using a distributed lag model. The estimates were pooled in the total areas and for each urban and rural area using meta-regression. In the total areas, the threshold point of heatwave mortality risk was estimated at the 93rd percentile of temperature, and it was lower in urban areas than in rural areas (92nd percentile vs. 95th percentile). The maximum risk of heatwave-related mortality in the total area was 1.11 (95% CI: 1.01-1.22), and it was slightly greater in rural areas than in the urban areas (RR: 1.23, 95% CI: 0.99-1.53 vs. RR: 1.10, 95% CI: 1.01-1.20). The results differ by age- and cause-specific deaths. In conclusion, the patterns of heatwave-related mortality risk vary by area and sub-population in Korea. Thus, more target-specific heatwave definitions and action plans should be established according to different areas and populations.

The Impact of Korean Medicine Treatment on the Incidence of Parkinson's Disease in Patients with Inflammatory Bowel Disease: A Nationwide Population-Based Cohort Study in South Korea.

We aimed to investigate the association between Korean medicine (KM) treatment and the risk of Parkinson's Disease (PD) in patients with inflammatory bowel disease (IBD) in South Korea. This study analyzed data from the National Health Insurance Service-Senior cohort in South Korea. The 1816 IBD patients enrolled in the analysis comprised 411 who received only conventional treatment (monotherapy group) and 1405 who received both conventional and KM treatments (integrative therapy group). The risk of PD in patients with IBD was significantly lower in the integrative therapy group than in the monotherapy group after adjusting for confounding variables (adjusted hazard ratio (HR), 0.56; 95% confidence interval (CI) = 0.34-0.92). In the mild Charlson Comorbidity Index (CCI) group, the risk of PD in patients with IBD in the integrative therapy group was 0.39 times lower (adjusted HR, 95% CI = 0.20-0.77) than that in the monotherapy group. However, there was no significant difference in the risk of PD in patients with IBD between the integrative therapy and monotherapy groups among individuals with severe CCI (adjusted HR, 0.90; 95% CI = 0.41-1.96). IBD patients are at a decreased risk of PD when they receive integrative therapy. KM treatment may prevent PD in IBD patients.