Relationship between Change in Physical Activity and Risk of Metabolic Syndrome: A Prospective Cohort Study.

Background: This study investigates the relationship between changes in physical activity levels and risk of metabolic syndrome. Methods: This study examined 1,686 adults aged 40 to 69 years from a community-based cohort study with complete 1st to 4th follow-up data between 2011 and 2020. Changes in physical activity were evaluated through baseline and follow-up surveys using physical activity questionnaires. Metabolic syndrome was diagnosed according to the International Diabetes Federation criteria. A survival analysis was conducted using a multivariate extended Cox regression model with a significance level set at P<0.05. Results: Participants were divided into groups according to physical activity levels. The newly inactive group (vigorous physical activity ≤150 minutes at first follow-up) had a 36% increase in the hazard ratio (HR) for metabolic syndrome compared with the consistently inactive group (≤150 minutes at both baseline and first follow-up) (HR, 1.36; 95% confidence interval [CI], 1.04 to 1.79). The newly active group (walking ≤420 minutes per week at baseline and >420 minutes per week at first follow-up) had a 25% decrease in the HR for metabolic syndrome compared with the consistently inactive group (walking ≤420 minutes per week at both baseline and first follow-up) (HR, 0.75; 95% CI, 0.57 to 0.98). Conclusion: Changes in physical activity levels are associated with risk of metabolic syndrome. These results provide important insights for future investigations into the link between physical activity changes and disease occurrence.

Fine dust inflow paths and heating load variation based on field measurement of air tightness in two Korean schools.

This study aimed to determine the effects of fine dust reduction, as well as the energy load reduction in association with the improvement plans by measuring the airtightness and indoor and outdoor fine dust concentrations in middle and high school classrooms and by identifying the fine dust inflow paths. The air tightness and indoor and outdoor fine dust concentrations were measured at two schools, and the paths of outdoor fine dust inflow were identified for an extensive analysis of the effects of fine dust reduction and the energy load reduction in association with improvement plans. Air tightness in the classroom at school A and B was improved by 32.26% and 38.58% with sealing, respectively. Analyzing the outdoor air inflow paths at school B according to the variation in air tightness, the probability of outdoor air inflow increased in the following order from the highest to the lowest: corridor windows, corridor doors, exterior windows, supply and exhaust units. For the rate of reduction in heating load, the highest rate was shown to be 27% at school A with improved air tightness at the exterior windows and 32% at school B with improved air tightness at the interior doors. This is expected to be reflected in the selection of equipment such as heat pumps and show cost-saving effects such as capacity reduction.

Performance and economic efficiency analysis of an integrated, outdoor fan-ventilated cooling device.

Recently, the importance of mechanical facilities in charge of the safety and comfort of occupants in buildings has once again been highlighted in accordance with global social issues such as the spread of COVID-19. In response, various ventilation systems are being developed to improve indoor air quality, and efforts are being made to satisfy the indoor comfort of the occupants. Such advanced facilities allow occupants to secure indoor air quality, while frequent ventilation systems can affect the cooling and heating load in the building, and there is also a problem that it can occupy a relatively large amount of space in the building. This study proposes an integrated, outdoor fan-ventilated cooling device and analyzes its performance and economic efficiency. The EnergyPlus simulation program was used to model two types of systems for comparison: an existing (base) model with a condenser located in the outdoor unit, and a developed model with the condenser integrated within the cooling system. The state of the air passing through the condenser was analyzed prior to comparing the efficiency of the integrated, outdoor fan-ventilated cooling device, followed by an in-depth analysis of the performance and economic efficiency based on total energy consumption. In Case 1, the air passing through the cooling system was approximately 5  °C lower than the base model and showed 11% peak load reduction in comparison to the maximum energy consumption. Additionally, a comparison between regions with different outdoor air temperatures showed an average cost reduction of 16% in Daejeon and Busan City.

Developing energy based benchmark model and detailed energy analysis through school statistical data and field surveys.

Approximately 20% of all school facilities, i.e., 7,980 buildings, are at least 40 years old in Korea. As the number of aged buildings is expected to rapidly increase, it is necessary to improve such facilities to protect safe learning environments and save energy. This study aims to develop the energy based benchmark model (EBBM) and utilization for energy saving in school. EBBM can be operated for school buildings, a category encompassing complex buildings with different systems and large gaps between them. To utilization of EBBM allows us to obtain knowledge from the school facility, in order to define and tune data driven analysis rules. Data driven energy analysis also allows ascertaining their expected energy consumption and estimating the possible saving systems by using the building energy flow chart. In this research, Korea education data-base was analyzed to classify energy based benchmark model. Applicability review is conducted through detailed system analysis of 10 schools. The difference between the benchmark model calculated value and the actual value was confirmed to be within 10%. Through the benchmarking model, it is possible to compare energy consumption for buildings of different sizes. Energy consumption by energy source and room type was analyzed through an in-depth status survey. Most of School Classrooms consume the largest amount of energy, with cooling and heating energy constituting the largest proportion.

The association between sedentary behavior, physical activity and hyperuricemia.

BACKGROUND: A significant discovery was recently made in which participation in physical activity and sedentary behavior, two contrasting lifestyles, was found to be related to the frequency of hyperuricemia diagnosis. The purpose of this study was to identify the association between sedentary behavior and physical activity levels in South Korean men and women diagnosed with hyperuricemia. METHODS: This study included 161,064 healthy men and women participants who had obtained a complete health examination. Physical activity levels and sitting time were assessed by the validated International Physical Activity Questionnaire Short Form Korean version. The presence of hyperuricemia in the subjects was determined by measuring serum uric acid (SUA) concentration (SUA ≥6 mg/dL [male], SUA ≥7 mg/dL [female]). Logistic regression analysis, adjusting other confounding factors, was conducted to identify the association of sedentary behavior and physical activity levels with hyperuricemia (p<0.05). RESULTS: Subjects who spent ≥10 hr/day in sedentary behavior were more likely to have hyperuricemia than those who spent <5 hour/day in sedentary behavior (OR=1.08, 95% CI=1.03-1.12). The subject group that more frequently participated in health enhanced physical activity (HEPA) had a lower hyperuricemia odds ratio than the subject group with lower physical activity participation rate (OR=0.90, 95% Ci=0.86-0.93). From the analysis of sex (male, female), age (young, middle, older), methods of measuring obesity (body mass index, waist circumference, body fat percentage), the association of sedentary behavior and physical activity levels with hyperuricemia was shown differently in different multivariable models. CONCLUSION: Participation in regular physical activity and reduced sedentary time is highly recommended in order to reduce the prevalence of hyperuricemia.

Blood levels of cadmium and lead in residents near abandoned metal mine areas in Korea.

We analyzed national data on blood lead levels (BLL) and blood cadmium levels (BCL) in residents living near 38 abandoned metal mining areas (n = 5,682, 18-96 years old) in Korea that were collected by the first Health Effect Surveillance for Residents in Abandoned Metal mines (HESRAM) from 2008 to 2011. The geometric mean BCL and BLL were 1.60 µg/L (95 % CI = 1.57-1.62 µg/L) and 2.87 µg/dL (95 % CI = 2.84-2.90 µg/dL), respectively, notably higher than levels in the general population in Korea and other countries. We found significantly higher BLL and BCL levels in people living within 2 km of an abandoned metal mine (n = 3,165, BCL = 1.87 µg/L, BLL = 2.91 µg/dL) compared to people living more than 2 km away (n = 2,517, BCL = 1.31 µg/L, BLL = 2.82 µg/dL; P < 0.0001) and to the general population values reported in the literature.

A survey for rhinitis in an automotive ring manufacturing plant.

We report findings regarding otolaryngologist-confirmed rhinitis, current exposure to MWF aerosols, fungi, and endotoxins for workers in a plant manufacturing automobile piston rings. Questionnaire data showed that 61.5% of 187 workers exhibited rhinitis-related symptoms. Rhinitis was confirmed in 99 of 115 workers whom were medically examined. Otolaryngologist-confirmed rhinitis was present in 10 of 19 grinding workers (52.6%), 67 of 142 production workers (47.2%), and 22 of 26 quality control (QC) workers (84.6%). These rates are much higher than the rates of rhinitis-related symptoms in automobile plants and other occupational settings and quite high even allowing for the common occurrence of rhinitis in the general population. We found that rhinitis could develop even in workers exposed to less than 0.5mg/m(3) MWF aerosol. The average exposure to fungi exceeded 10 x 10(3) CFU/m(3), a level higher than that reported for other automobile plants. Although we were unable to identify significant risk factors for rhinitis using only the physician-confirmed rhinitis cases, this study concludes that exposure to MWF aerosol, which would include microbes and metals, could contribute to a high occurrence of rhinitis in grinding and production workers. Forty-nine workers (63.6%) of 77 rhinitis patients in grinding and production operations were determined to handle synthetic MWF directly. For QC workers, for whom the prevalence of physician-confirmed rhinitis was highest, exposure to a low level of MWF aerosol, including specific microbe species we couldn't identify, bright light, dry air, and certain work characteristics during inspection are possible risk factors for development of rhinitis. Further studies including identification of fungi species should be conducted so a firm conclusion can be made regarding the development of rhinitis in QC manufacturing plant workers.

[The incidence and patterns of unintentional injuries in daily life in Korea: a nationwide study].

OBJECTIVES: This study was conducted to estimate the cumulative incidence rate (CIR) of unintentional injuries in Korean daily life and to describe the pattern of unintentional injuries. METHODS: The study population was the people who used the National Health Insurance because of injuries (ICD code: S00-T98) during 2006. The stratified sample according to gender, age and the severity of injury (NISS, New Injury Severity Score) was randomly selected. The questions on the questionnaire were developed as a reference for an international classification tool (ICECI, International Classification of External Causes of Injury). The questions included the locations of injury, the mechanisms of injury and the results of injury. Moreover, we used age, gender, region and income variables for analysis. RESULTS: The CIR of unintentional injuries that occurred in daily life for 1 year per 100,000 persons was 17,606, and the CIR of severe injuries was 286. Many injuries were occurred at home (29.6%), public places (19.0%), school (13.7%) and near home (12.0%). The major mechanisms of injuries were slipping (48.8%), contact (14.0%), physical over-exertion (13.8%), and fall (6.6%). Infants and old aged people were vulnerable to injuries, and those who lived rural area and who were in a low income level were vulnerable too. CONCLUSIONS: We signified the risk groups and risk settings of unintentional injuries in Korean daily life. These results could contribute to establishing strategies for injury prevention and implementing these strategies.

Association between use of synthetic metalworking fluid and risk of developing rhinitis-related symptoms in an automotive ring manufacturing plant.

The main objective of this study was to determine the association between synthetic metalworking fluid (MWF) and rhinitis-related symptoms. At a plant manufacturing piston rings for automobiles, we interviewed grinders (19) and manufacturing workers (142) in operations where synthetic or semisynthetic MWF is handled, and administrative office workers (44) regarding the principal symptoms of rhinitis (nasal stuffiness, runny nose, anosmia, nasal itchiness, rhinorrhea, headache, epistaxis, and post-nasal drip). In addition, we assessed the current exposure of workers handling MWF to MWF aerosols, fungi, and endotoxins. Logistic regression analysis was used to examine the association between MWF surrogates indicative of MWF exposure and each rhinitis-related nasal symptom. Odds ratios (ORs) and 95% confidence intervals were adjusted for sex, age, smoking habit, and duration of employment. Among grinders handling synthetic MWF, the frequency of complaints of the dominant symptoms was 66.7% for nasal stuffiness, 77.8% for anosmia, 77.8% for runny nose, and 50.0% for headache. These rates are quite high even allowing for the common occurrence of rhinitis in the general population. Twenty eight of 34 grinding and manufacturing workers (82.4%) sampled were exposed to MWF mist above the threshold limit of 0.2 mg/m(3) listed as a notice of intended change by the American Conference for Governmental Industrial Hygienists (ACGIH). The percentage of workers exposed to MWF mist >0.5 mg/m(3) was 17.6%. Most workers were exposed to fungi levels >103 CFU/m(3). All exposures to endotoxins were <50 EU/m(3). Logistic regression analysis found that use of synthetic MWF was significantly associated with excess risk of nasal stuffiness (OR 3.5), nasal itchiness (OR 2.0), and runny nose (OR 2.1). The use of semi-synthetic MWF had little or no impact on the risk of developing rhinitis-related nasal symptoms. Grinding workers handling synthetic MWF had an increased risk of nasal stuffiness (OR 7.9), anosmia (OR 23.2), nasal itchiness (OR 8.3), runny nose (OR 20.4), post nasal drip (OR 18.4), and headache (OR 7.4) compared to administrative workers. Synthetic MWF may play an important role in the development of the dominant symptoms of rhinitis. Further study is needed to establish the risk of rhinitis or rhinitis-related symptoms according to MWF type.

The development and regulation of occupational exposure limits in Korea.

With the institution of the new chemical regulatory framework in 2003, chemicals at the workplace have been classified into five categories; banned substances, permission-required substances, regulated substances, occupational exposure limit set substances, and other generally controlled substances. Currently, there are 698 substances with OELs. As we have come to gain our own experiences in the study and control of chemical hazards at the workplace such as the 2-bromopropane poisoning, OEL setting process has been streamlined. The OELs in Korea, however, remain merely as a recommendation, which does not require all the substances with OELs to be measured at the workplace. Coordination of whole program for hazardous chemicals including workplace measurement, OEL setting process, and enforcement activities is still needed in Korea.