PURPOSE: This retrospective study was conducted to estimate the effects of climate factors and air pollution on asthma exacerbations using a case-crossover analysis. METHODS: Patients who visited the emergency department (ED) of 2 university hospitals in Chuncheon for asthma exacerbations from January 1, 2006, to December 31, 2011, were enrolled. Daily average data for meteorological factors (temperature, daily temperature range, relative humidity, wind speed, atmospheric pressure, presence of rain, solar irradiation, and presence of fog) and the daily average levels of gaseous air pollutants (SO2, NO2, O3, CO, and PM10) were obtained. A case-crossover analysis was performed using variables about the weather and air pollution at 1-week intervals between cases and controls before and after ED visits. RESULTS: There were 660 ED visits by 583 patients with asthma exacerbations. Low relative humidity (lag 1 and 2) and high wind speed (lag 1, 2, and 3) were associated with ED visits for asthma. Fog (lag 2) showed protective effects against asthma exacerbations in Chuncheon (risk increase: -29.4% [95% CI=-46.3% to -7.2%], P=0.013). These relationships were stronger in patients ≤19 years old than in those >60 years old. High levels of ambient CO (lag 1, 2, and 3) and NO2 (lag 2 and 3) were associated with decreased ED visits for asthma. However, there were no significant relationships among levels of ambient CO or NO2 and asthma exacerbations after adjusting for wind speed and relative humidity. CONCLUSIONS: High wind speed and low humidity were associated with an increased risk of asthma ED visits. Fog was associated with a decreased risk of asthma ED visits after controlling for seasonal variations in weather and air pollution.
Air Pollutants ; Air Pollution* ; Asthma* ; Atmospheric Pressure ; Climate ; Emergencies* ; Emergency Service, Hospital* ; Gangwon-do* ; Hospitals, University ; Humans ; Humidity ; Korea* ; Meteorological Concepts ; Rain ; Retrospective Studies ; Seasons ; Weather* ; Wind

BACKGROUND AND OBJECTIVES: Epistaxis may be related to changes in weather, but this relationship has not been well-defined. We investigated the effects of climate fluctuations (temperature, humidity, and barometric pressure) on the number of emergency department (ED) visits for epistaxis. SUBJECTS AND METHOD: In total, our study population included 1910 patients who visited the ED of a large, urban hospital during a 5-year period for epistaxis. Patients with clear etiology for epistaxis (trauma, iatrogenic, coagulopathy, and/or hypertension) were excluded, leaving 912 patients for subsequent analysis. Daily climate data was collected through the Korea Meteorological Administration. Correlation between epistaxis ED visits and weather variables were investigated using Poisson distribution and multiple regression analysis. The effect of climate factor was evaluated on the day and up to 3 days prior to ED presentation. Additionally, analyses were conducted separately for children (<15 years-old), adults (15-64 years-old), and elderly patients (> or =65 years-old). RESULTS: Changes in the lowest temperature 2 days prior to ED presentation significantly increased the number of ED visits for epistaxis (beta=-0.043, p=0.033). No associations were found between the number of ED visits and changes in humidity or atmospheric pressure. However, in children, interday changes in the highest atmospheric pressure between 2 and 3 days prior to ED presentation were both significantly associated with increased number of epistaxis ED visits. CONCLUSION: Cold temperatures 2 days prior to ED presentation were related to the increased incidence of epistaxis. Fluctuations in barometric pressure appear to influence the number of pediatric ED visits for epistaxis.
Adult ; Aged ; Atmospheric Pressure ; Child ; Climate ; Cold Temperature ; Emergency Service, Hospital* ; Epistaxis* ; Hospitals, Urban ; Humans ; Humidity ; Incidence ; Korea ; Meteorological Concepts* ; Weather

BACKGROUND: Despite the evident age differences in the risk of asthma attack due to air pollution, most studies have recruited subjects from all age groups. Although this effort might be feasible for maintaining statistical power, it biases the effect estimate towards the null among children who are more sensitive to air pollution than adults. OBJECTIVES: To estimate the risk of air pollution on children living in Seoul who have made doctor visits for asthma. METHOD: From 1992 to 1993, daily number of doctor visits due to asthma attack was tallied among children between 4 and 11 years old living in Seoul from the insurance claim forms of Korean Medical Insurance Corporation (KMIC). 24-hour mean concentrations were calculated for TSP, SO2, O3 and NO2 based on hourly concentrations measured at 20 monitoring stations. To estimate the effect of TSP or SO2 on asthma attack, a Poisson regression model was used with adjustments for long-term trend, seasonal variation, day-of-week effect, and meteorological factors such as temperature, humidity, wind velocity and duration of sunshine. To prevent autocorrelation, autoregressive error terms were tried with different lag periods. RESULTS: The cumulative effect of a current day and previous five days turned out to be stronger than that of any single day. These relationships were observed more clearly after the effects of O3 and NO2 were controlled. For 100microgram/m3 increase of cumulative concentration of TSP, the relative risk was 1.27 (95% CI: 1.08, 1.49); for 50ppb increase of cumulative concentration of SO2, the relative risk was 1.56 (95% CI: 1.29, 1.89). After the effects of O3 and NO2 were removed in a multiple regression model, it increased to 1.37 (95% CI: 1.10, 1.69) and 1.66 ((%% CI: 1.34, 2.07), respectively. CONCLUSION: The concentrations of TSP and SO2 turned out to be significantly associatedwith asthma attack among children. As expected, the risk estimates were larger than those of previous studies which recruited subjects from all age groups, or used mortality or hospitalization as their outcome.
Adult ; Air Pollution* ; Asthma* ; Bias (Epidemiology) ; Child ; Hospitalization ; Humans ; Humidity ; Insurance ; Meteorological Concepts ; Mortality ; Seasons ; Seoul* ; Sunlight ; Wind

OBJECTIVE: The aim of this study was to investigate the correlation between meteorological factors and occurrence of spontaneous intracerebral hemorrhage (ICH) according to age. MATERIALS AND METHODS: We retrospectively analyzed the records of 735 ICH patients in a metropolitan hospital-based population. Observed and expected numbers of ICH patients were obtained at 5degrees C intervals of ambient temperature and a ratio of observed to expected frequency was then calculated. Changes in ambient temperature from the day before ICH onset day were observed. The Wilcoxon-Mann-Whitney test was used to test differences in meteorological variables between the onset and non-onset days. The Kruskal-Wallis test was used for comparison of meteorological variables across gender and age. RESULTS: ICH was observed more frequently (observed/expected ratio > or = 1) at lower mean, minimum, and maximum ambient temperature (p = 0.0002, 0.0003, and 0.0002, respectively). Significantly lower mean, minimum, and maximum ambient temperature, dew point temperature, wind speed, and atmospheric pressure (p = 0.0003, 0.0005, 0.0001, 0.0013, 0.0431, and 0.0453, respectively) was observed for days on which spontaneous ICH occurred. In the subgroup analysis, the ICH onset day showed significantly lower mean, minimum, and maximum ambient temperature, dew point temperature, relative humidity, and higher atmospheric pressure in the older (> or = 65 years) female group (p = 0.0093, 0.0077, 0.0165, 0.0028, 0.0055, and 0.0205, respectively). CONCLUSION: Occurrence of spontaneous ICH is closely associated with meteorological factors and older females are more susceptible to lower ambient temperature.
Atmospheric Pressure ; Cerebral Hemorrhage* ; Female ; Humans ; Humidity ; Meteorological Concepts* ; Meteorology ; Retrospective Studies ; Wind

PURPOSE: This study shows the relationship between meteorological factors and the number of community acquired pneumonia (CAP) patients in the emergency room and lag effect of meteorological factors affecting CAP. METHODS: A retrospective study was conducted. Patients diagnosed with CAP in the emergency room between January 2012 and December 2014 were enrolled. The patients were over 18 years old and lived in Seoul, Korea. Meteorological factors (highest daily temperature, lowest temperature, mean temperature, diurnal temperature, rainfall, relative humidity, amount of sunshine, and powdery dust under 10 microg/m3 (PM10)) between December 2011 and December 2014 in Seoul were acquired from the Korea Meteorological Administration. Multiple Poisson regression (Generalized Linear Model) was used with daily patient's number of CAP as the response variable and meteorological factors as the explanatory variable. Variable selection was performed via Elastic net. RESULTS: A total of 568 CAP patients were checked. Highest temperature (before 6 days), rainfall (before 1 day), relative humidity (before 20, 15, 13, 6, 2, and 1 days), and PM10 (before 27, 24, 17, and 13 days) showed relationship and lag effect with the incidence of CAP. CONCLUSION: This study showed that meteorological factors (highest temperature, rainfall, relative humidity, and PM10) had relationship and lag effect with the incidence of CAP. We can make a prediction model with health weather index for prevention of CAP and redistribution of medical facilities and resources.
Dust ; Emergency Service, Hospital ; Humans ; Humidity ; Incidence ; Korea ; Meteorological Concepts ; Pneumonia* ; Regression Analysis ; Retrospective Studies ; Seoul ; Sunlight ; Weather*

PURPOSE: This study examined the influence of meteorological phenomena on the development of spontaneous pneumothorax (SP). METHODS: We conducted this study from January to November 2004. We obtained the daily SP incidence from data requested by the National Health Insurance office from general hospital in Daejon, and we got the meteorological data from the Daejon Regional Meteorologic office. The difference in meteorological phenomena between cluster days (3 or more SP) and no SP days was analyzed using a generalized additive model (GAM) that used a specialized form of the non-parametric, non-linear regression test. RESULTS: Five hundred sixty-six SP patients were included. There were 369 male patients and 74 female patients. SP patients were associated with significantly lower atmospheric pressure and with broad swings of daily atmospheric pressure for 4-7 days prior to the hospital visits. More clouds had gathered for several days before cluster days than had gathered on days with no SP. CONCLUSION: Development of SP is related with meteorological phenomena. SP occurs when lower atmospheric pressure, broad swings of atmospheric pressure, and cloudy weather are collectively exprienced for several days before the hospital visit.
Atmospheric Pressure ; Daejeon ; Female ; Hospitals, General ; Humans ; Incidence ; Male ; Meteorological Concepts ; National Health Programs ; Pneumothorax* ; Weather

OBJECTIVETo investigate the relationship between respiratory diseases onset and the meteorological factors in the same period and in a specific environment. METHODS METHODS: By using the data of daily incidence of respiratory diseases obtained from Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine from January 1, 1998 to December 31, 2007, and the data of 16 items of meteorological factors (such as the average, maximum, and minimum temperatures, etc., including meteorological factors derived) obtained from the Beijing Municipal Meteorological Observatory, mathematical statistical methods were applied to achieve the non-linear correlation analysis, or the correlation test, between the incidence of respiratory diseases and the time-related meteorological factors.

RESULTSThe simple correlation coefficients of the relationship between the incidence of respiratory diseases and 9 meteorological elements, including the average values of temperature, maximum temperature, minimum temperature, degree of comfort, precipitation, vapor pressure, low cloud cover, change of vapor pressure, and change of wind speed, were all greater than 0.8286, in which one of the relationship between the incidence of respiratory diseases and the maximum temperature is as high as 0.9670. Statistical tests showed R>Rα=0.05 and F>Fα=0.05.

CONCLUSIONSThe incidence of respiratory diseases was closely correlated to meteorological factors, such as air temperature, vapor pressure, precipitation, wind speed, etc. To a certain extent, this conclusion confirmed the scientificity and objectivity of the theory of five evolutive phases and six climatic factors (Wu Yun Liu Qi ) in Huang Di Nei Jing (The Yellow Emperor's Canon of Internal Medicine).

Air ; China ; epidemiology ; Humans ; Humidity ; Incidence ; Medicine, Chinese Traditional ; Meteorological Concepts ; Respiratory Tract Diseases ; epidemiology ; etiology ; Statistics as Topic ; Steam ; Time Factors ; Wind

Air-borne pollen is known as one of the major causal agents to respiratory allergic reactions. The daily number of pollen grains was monitored using Burkard volumetric spore traps at eight locations including Seoul and Jeju during 1997-2005. Pollen grains were observed throughout the year especially from February to November. They showed similar distribution patterns of species among locations except Jeju, where Japanese cedar vegetation is uniquely found. The peak seasons for pollen grains from trees, grasses, and weeds were from March to May, May to September, and August to October. Tree pollens were mainly composed of pine, oak, alder, and birch. Weed pollens were mainly from Japanese hop, sagebrush, and ragweed. The diameter of pollen grains, which has a typical range of 20~60 micrometer, has close relationship with allergenicity. The allergenicity of trees and weed pollens is higher than that of grass pollens in general. Daily fluctuations in the amount of pollens have to do with a variety of meteorological factors such as temperature, rainfall, and the duration of sunshine. Temperature and rainfall are especially decisive in determining pollen concentrations. Ten weather elements that are thought to affect the concentration of pollens are used to develop equations for the pollen forecasts. Predictive equations for each pollen species and month are developed based on statistical analyses using observed data during the last 5 years in Seoul through a co-work with the Committee of Pollen Study in Korean Academy of Pediatric Allergy and Respiratory Diseases and National Institute of Meteorological Research.
Alnus ; Ambrosia ; Artemisia ; Asian Continental Ancestry Group ; Betula ; Cryptomeria ; Humans ; Humulus ; Hypersensitivity ; Meteorological Concepts ; Poaceae ; Pollen ; Seasons ; Spores ; Sunlight ; Weather

BACKGROUND AND OBJECTIVES: The objective of this study was to evaluate the effect of meteorological factors on the onset of vestibular neuritis. MATERIALS AND METHODS: Meteorological data from 2004 to 2009 were obtained from the web-based 'Monthly Weather Reports of the Meteorological Administration' database. Patients with vestibular neuritis who visited Incheon St. Mary's Hospital during this same period and presented the precise day on which the symptoms appeared were included in this study involving a retrospective chart review. Twelve meteorological factors were analyzed between the days when vestibular neuritis onset was observed and the days when vestibular neuritis did not occur. Time lags (D-1-D-7) which mean 1-7 days before the onset were included to assess a possible delayed meteorological effect in relation to the onset of vestibular neuritis. Seasonal incidence of vestibular neuritis and a relationship with seasonal patterns of weather parameters were evaluated. RESULTS: Mean values for the meteorological parameters of the days when vestibular neuritis occurred were not significantly different from the days on which vestibular neuritis onset was not observed. At time lag of 3-5 days, mean and maximal wind velocities were significantly higher for the days when vestibular neuritis occurred than the days without vestibular neuritis onset. The incidence of vestibular neuritis was highest in spring, when the wind velocity was higher compared to other seasons. CONCLUSION: Wind speed and the spring season showed significant relationships with vestibular neuritis occurrence.
Humans ; Incidence ; Meteorological Concepts ; Retrospective Studies ; Seasons ; Vestibular Neuronitis ; Weather ; Wind

PURPOSE: Febrile seizure (FS) is the most common type of seizure in children between 6 months to 5 years of age. A family history of febrile seizures can increase the risk a child will have a FS. Yet, prevalence of FS regarding external environment has not been clearly proved. This study attempts to determine the association between prevalence of FS and weather. METHODS: This study included medical records from the Korea National Health Insurance Review and Assessment Service. Data were collected from 29,240 children, born after 2004, diagnosed with FS who were admitted to one of the hospitals in Seoul, Korea, between January 2009 and December 2013. During the corresponding time period, data from the Korea Meteorological Administration on daily monitoring of four meteorological factors (sea-level pressure, amount of precipitation, humidity and temperature) were collected. The relationships of FS prevalence and each meteorological factor will be designed using Poisson generalized additive model (GAM). Also, the contributory effect of viral infections on FS prevalence and weather will be discussed. RESULTS: The amount of precipitation was divided into two groups for comparison: one with less than 5 mm and the other with equal to or more than 5 mm. As a result of Poisson GAM, higher prevalence of FS showed a correlation with smaller amount of precipitation. Smoothing function was used to classify the relationships between three variables (sea-level pressure, humidity, and temperature) and prevalence of FS. FS prevalence was correlated with lower sea-level pressure and lower humidity. FS prevalence was high in two temperature ranges (-7 to -1℃ and 18–21℃). CONCLUSION: Low sea-level pressure, small amount of precipitation, and low relative air humidity may increase FS prevalence risk.
Child* ; Fever ; Humans ; Humidity ; Korea ; Medical Records ; Meteorological Concepts ; National Health Programs ; Prevalence* ; Seizures ; Seizures, Febrile* ; Seoul ; Weather*