Asthma and temperature change. II. 1964 and 1965 epidemiological studies of emergency clinic visits for asthma in three large New York City hospitals

Relationship between biometeorological factors and the number of hospitalizations due to asthma

The incidence of asthma exacerbation depends on atmospheric conditions, including such meteorological factors as the ambient temperature, relative air humidity or concentration of atmospheric aerosols. An assessment of relations between the frequency of asthma exacerbation and environmental conditions was made according to the meteorological components, the biometeorological index UTCI (Universal Thermal Climate Index), as well as selected air quality parameters, including concentrations of PM₁₀ and PM_2.5. The study was conducted on the basis of a retrospective analysis of medical data collected at the Independent Public Hospital of Tuberculosis and Pulmonary Diseases in Olsztyn (Poland). Our analysis of patient data (from 1 January 2013 until 31 December 2017) showed a significant correlation between the number of asthma exacerbation and the UTCI value. More frequent asthma exacerbations are observed in patients aged over 65 years when air humidity increases. The UTCI values contained within class 5, describing thermoneutral conditions, correspond to an average frequency of asthma exacerbation. A decline in the UTCI value leads to a reduced number of asthma exacerbation, while a rise makes the cases of asthma exacerbations increase.

Relating weather types to asthma-related hospital admissions in New York State

Many previous studies have looked into the relationship between asthma and individual weather variables, but comparatively few have looked at this relationship using holistic weather types (WTs). Utilizing the Spatial Synoptic Classification, this research considers up to 6 days of lag time while investigating the asthma-to-WT relationship in two age groups (under 18 and 18 and over) throughout New York State. Results indicate that a cold and dry WT in autumn corresponds to increased asthma admissions and spike days in admissions in New York City (NYC) for the school-aged population, while hot and dry WTs in summer correspond to spike days in asthma admissions in both age groups. However, results vary considerably for other regions, seasons and WTs, and spike day analysis yields clearer results than the analysis of total anomalous admissions. When stratified by multiple regions and age groups, the sample size of daily asthma admissions is a limiting factor outside of NYC.

Short-term outdoor temperature change and emergency department visits for asthma among children: a case-crossover study

Although weather changes are known to cause asthma symptoms, their impact on asthma-related health-care utilization is poorly understood. The objective of the present study was to determine the association between short-term outdoor temperature change and asthma-related emergency department (ED) visits among children 3-18 years of age in Detroit, Michigan, in 2000-2001. Descriptive analyses of patient and ED visit characteristics were performed. A case-crossover study utilizing time-stratified controls was conducted to determine the impact of maximum temperature change and change rate measured during 4-, 8-, 12-, and 24-hour periods. Multivariable conditional logistic regression demonstrated the relation between ED visits and temperature change after controlling for other weather and pollutant measures. There were 4,804 asthma-related ED visits during the study period, and they occurred most frequently in the fall and during morning hours. The case-crossover study showed a statistically significant inverse relation between ED visits and maximum 24-hour temperature change after adjustment for climatic factors (for temperature change, odds ratio = 0.992, P = 0.04; for temperature change rate, odds ratio 0.972, P = 0.01). The association persisted after air pollutant measures were added to the model, although the association was not significant. Despite the finding that a greater 24-hour temperature change decreased the risk of asthma-related ED visits, the overall results suggested a negligible association with short-term temperature change.

Frequency of emergency room visits for childhood asthma in Ottawa, Canada: the role of weather

The aim of this study was to evaluate associations between meteorological conditions and the number of emergency department visits for asthma in a children's hospital in Ottawa, Canada. A case-crossover study design was used. Hospital emergency department visits for asthma between 1992 and 2000 were identified based on patients' presenting complaints. We obtained hourly measures for the following meteorological variables: wind speed, temperature, atmospheric pressure, relative humidity, and visibility. Particular emphasis was placed on exploring the association between asthma visits and fog, thunderstorms, snow, and liquid and freezing forms of precipitation. In total, there were 18,970 asthma visits among children between 2 and 15 years of age. The number of visits and weather characteristics were grouped into 6 h case and control intervals. The occurrence of fog or liquid precipitation was associated with an increased number of asthma visits, while snow was associated with a reduced number (P<0.05). Stratified analyses by season found no association in any of the four calendar intervals between the number of asthma visits and visibility, change in relative humidity and change in temperature. In contrast, summertime thunderstorm activity was associated with an odds ratio of 1.35 (95% CI=1.02-1.77) relative to summer periods with no activity. Models that incorporate calendar and meteorological data may help emergency departments to more efficiently allocate resources needed to treat children presenting with respiratory distress.

Influence of climate factors on emergency visits for childhood asthma attack

BACKGROUND

Asthma attack shows strong seasonality. The purpose of the present study was to quantify the contribution of climate variables and other seasonal factors on the incidence of emergency visits for childhood asthma in Tokyo, Japan.

METHODS

The number of children who visited emergency rooms at Jikei university hospitals in Tokyo during 1998-2002 (5559 visits) was retrieved retrospectively from files from the Department of Pediatrics, and compared with 45 climate parameters from the Meteorological Agency using multiple regression models with a stepwise backward elimination approach.

RESULTS

The number of visits (3.7 +/- 3.1) per night increased significantly when climate conditions showed a rapid decrease from higher barometric pressure, from higher air temperature and from higher humidity, as well as lower wind speed. The best-fit model demonstrated that a 22% variation in the number of visits was explained by a linear relationship with 12 climate variables, which increased to 36% after adjusting for calendar month and day of the week. Moreover, when the number of asthma visits was cut off at nine per night, the area under the receiver operator characteristics curve was 0.91 (95% CI: 0.89-0.94) in the multiple logistic regression model using the same variables.

CONCLUSIONS

These results suggest that these models might quantify contributions of specific climate conditions and other seasonal factors on the number of emergency visits per night for childhood asthma attack in Tokyo, Japan.

Are high barometric pressure, low humidity and diurnal change of temperature related to the onset of asthmatic symptoms?

BACKGROUND

Meteorologic factors play a role in the expression of asthmatic symptoms; however, there are controversies about the causal relationship between meteorologic factors and asthma. The relationship between meteorologic parameters and emergency admissions for asthmatic symptoms in this hospital were analyzed.

METHODS

A total of 205 patients (130 boys and 75 girls, 0.1-16.6 years of age) who were admitted to Hakodate Chuo General Hospital for asthmatic symptoms between 1 January and 31 December 1997 were submitted to our study. We divided a total of 365 days into two groups of days with and without any admissions. Meteorologic factors for the days with admissions and 1-3 days before hospitalization were compared with those of the days of no admissions. Statistical analysis was done with the Mann-Whitney U-test.

RESULTS

On the days with admissions and 1 day before hospitalizations, barometric pressure was higher and relative humidity lower than on days with no admissions. The diurnal difference between maximum and minimum temperature for days 1 day before days with admissions was larger than that for 1 day before days with no admissions.

CONCLUSIONS

It is thought that change in barometric pressure, relative humidity and temperature had some influence on the worsening of asthmatic symptoms.

A synoptic evaluation of asthma hospital admissions in New York City

An evaluation of weather/asthma relationships in the New York City Standard Metropolitan Statistical Area (SMSA) is developed using a synoptic climatological methodology. This procedure isolates "air masses," or bodies of air that are homogeneous in meteorological character, and relates them to daily counts of overnight asthma hospital admissions. The synoptic procedure used here, known as the temporal synoptic index (TSI), can identify air masses in automated fashion for every day over many years. It is apparent that certain air masses are related to statistically significant increases in asthma hospital admissions. The impact varies seasonally, with weather having a particularly important impact on asthma admissions during fall and winter. It appears that air pollution has little impact on asthma during these two seasons, and the air masses associated with the highest admissions are not distinguished by high concentrations of pollutants. However, during spring and summer, the air masses associated with highest admissions are among those with high pollution concentrations. There is a strong interseasonal differential response to weather and air pollution by asthmatics in New York City. If these results can be replicated at other locations in future studies, it may be possible to develop an asthma/weather watch-warning system, based on the expected arrival of high-admissions air masses.

Effects of the combination of skin cooling and hyperpnea of frigid air in asthmatic and normal subjects

To investigate whether reducing integumental temperature influences pulmonary mechanics and interacts with inhaling cold air, 10 normal and 10 asthmatic subjects participated in a three-part trial in which cooling the skin of the head and thorax and isocapnic hyperventilation of frigid air were undertaken as isolated challenges and then administered in combination. Integumental cooling for 30 min caused airway obstruction to develop in both populations [change in 1-s forced expiratory volume (delta FEV1) asthmatic subjects = 10% ; normal subjects = 6%)]. Hyperventilation, however, only affected the asthmatic subjects (delta FEV1 asthmatic subjects = 18%; normal subjects = 3%). In contrast to expectations, the combined challenge did not produce a summation effect (delta FEV1 asthmatic subjects = 21%; normal subjects = 7%). These data demonstrate that the skin of the trunk and head is cold sensitive and when stimulated causes similar degrees of bronchial narrowing in both normal subjects and patients with airway disease independent of any ventilatory effect. They also indicate that cooling of the skin does not add to the obstructive consequences of hyperpnea.

Risk factors for intubation of adult asthmatic patients

Our object was to describe demographic data from a population of adult asthmatics admitted to a regional tertiary medical center to identify risk factors for intubation. We performed a retrospective cohort study of all asthma admissions (International Classification of Diseases, Ninth Revision, Code 493.9) excluding cases with chronic obstructive pulmonary disease. This included all patients with asthma 20 years and above admitted to the University of California Davis Medical Center, Sacramento, from January 1, 1990 to June 30, 1993. A total of 375 asthma admissions were reviewed. There were 244 women (29 intubated) and 131 men (13 intubated) with a mean age of 40.7 (range 20-72) years. Of this group, 131 people were white, 140 black, 56 Hispanic, 42 Asian, and 6 American Indian. By National Heart, Lung, and Blood Institute Guidelines, there were 101 mild, 181 moderate, and 93 severe cases. Significant risk parameters identified for intubation were psychosocial problems [odds ratio (O.R.) 9.3; 95% confidence interval (C.I.) 6.8, 12.7], low socioeconomic group (O.R. 2.9; 95% C.I. 1.5, 5.8), little formal education (O.R. 5.4; 95% C.I. 2.8, 10.2), atopic allergy (O.R. 11.7; 95% C.I. 5.7, 23.7), duration of asthma > or = 15 years (O.R. 2.6; 95% C.I. 1.3, 5.3), previous intubation (O.R. 14.0; 95% C.I. 7.6, 25.6), upper respiratory infection (O.R. 4.0; 95% C.I. 2.2, 7.5), hospital admission for asthma within the last year (O.R. 5.3; 95% C.I. 2.7, 10.4), emergency room visit within the last year (O.R. 8.8; 95% C.I. 3.9, 20.1), and steroid dependency (O.R. 5.5; 95% C.I. 3.0, 10.2).(ABSTRACT TRUNCATED AT 250 WORDS)

School holidays and admissions with asthma

The admission rate for asthma at a children's hospital was studied over an 11 year period. Admissions varied unpredictably over periods of a few days, but there was a repeated yearly pattern of peaks and troughs with an interval of several weeks. The short term variation could be attributed to chance effects alone, excluding any important role for short term influences--for example, weather changes--in precipitating asthma admissions. There was a definite association between the longer term variation and school holidays. The admission rate fell during holidays and there were two or more peaks during terms. The pattern is consistent with a largely viral aetiology for asthmatic attacks throughout the year. We postulate that school holidays disrupt the spread of viral infections in a community, with synchronisation of subsequent attacks. Travel during holidays may facilitate acquisition of new viral strains by the community.

Seasonal patterns of asthma: a clue to etiology

An extensive data set of daily hospital emergency room visits for asthma for two geographic areas (1953-77 in New Orleans and 1969-77 in New York City) was examined for seasonality. Previous studies using smaller data bases have reported an autumn increase (principally during October and November) in the number of emergency room visits for asthma in many locations in this country (including New Orleans and New York City). The results of this study indicated that for every hospital and every year of observation in New York City the number of asthma emergency room visits increased in September, reached a peak in October and November and declined in December. In contrast, in New Orleans an autumn increase in the number of asthma emergency room visits was not consistently observed, being absent or reduced during many years. The distribution of asthma epidemic days (days on which the number of asthma emergency room visits was greatly elevated) by month was also examined. In New York City, there was a tendency for these days to occur during September, October, and November while in New Orleans there was an equal likelihood of epidemic days occurring in April, May, and June as well as during September, October, and November. The observations tend to suggest different etiologies for asthma attacks in the two geographic areas.

Daily patterns of asthma in New York City and New Orleans: an epidemiologic investigation

Examination of records of daily visits to emergency rooms for asthma covering 25 years from New Orleans and 9 years from New York City reveals a distinct day-of-the-week pattern in New York City whereas no such pattern is discernible in New Orleans. The difference in daily patterns of asthma attacks in the populations from the two cities strongly suggests a different environmental etiologic agent acting on these two populations. It is proposed herein that in New York susceptible individuals are exposed to some agents or factors triggering attacks which are present in the home environment where most of their time is spent on weekends, while in New Orleans, homes are not as sealed off from the outside air, because of the warmer climate, so that the agent triggering attacks is as common outdoors as indoors, and thus there is little difference between weekend and weekday exposure.

Allergenic factors and symptomatology of respiratory allergy patients

An attempt has been made in the present study to find out the relationship between the symptomatology of nasobronchial allergy patients of Delhi with markedly positive skin reactions and prevalence of total pollen concentration in the atmosphere, concentration of major individual pollen types, total fungal spores and house dust mites together with climatic factors such as mean monthly temperature and relative humidity. A statistically significant correlation was not found between symptomatology of the patients of Delhi and mean monthly relatively humidity, atmospheric concentration of pollen, fungal spores and house dust mites. A significant negative correlation was observed between symptomatology of patients and mean monthly temperature. Except for the pollen of prospis which showed significant positive correlation with the symptomatology of Delhi patients, a significant positive correlation was absent with respect to other individual pollen types.

Enhancement of exercise-induced asthma by cold air

To study the possibility that the inhalation of cold air accentuates the bronchoconstrictor response to exercise in asthma, eight subjects exercised while breathing air at ambient or subfreezing temperatures. On a separate day, cold air was breathed at rest so as to isolate the effects of this stimulus. Pulmonary mechanics were measured before and after each experiment. In all subjects acute bronchoconstriction followed the control exercise challenge. With cold-air breathing, however, the magnitude of the response was markedly enhanced. Residual volume increased 158 per cent more than it did previously, and specific conductance and one-second forced expiratory volumes changed an additional 85 and 100 per cent, respectively. The effects of cold air at rest were very small. The results demonstrate a positive interaction of two common naturally occurring stimuli in the induction of asthmatic attacks, and constitute objective verification of a frequent clinical complaint.

Time course of bronchoconstrictive response in asthmatic subjects to reduced temperature

Thirteen young adults with bronchial asthma and a like number of controls were subjected for 45 minutes to a temperature of 2 degrees C after leaving a temperature of 24 degrees C to which they subsequently returned. Pre-exposure examination included VC, FEV1, MMEF, FEV1/VC%, and urinary catecholamines. The pulmonary measurements were repeated at 15, 80, and 200 minutes after exposure. Catecholamines were measured from a second urine sample, the collection of which corresponded to the period during and after the stress. Controls showed no significant pulmonary changes throughout the time of study, but 15 minutes after exposure the asthmatic subjects showed a significant mean decrease of all pulmonary measurements from pre-exposure values. The controls showed a significant mean increase in urinary catecholamines after the stress, whereas those with asthma showed no significant increase.