Prevalence of adult asthma symptoms in relation to climate in New Zealand

Greenness and chronic respiratory health issues: a systematic review and meta-analysis

Introduction

The number of chronic respiratory disease (CRD) individuals worldwide has been continuously increasing. Numerous studies have shown that greenness can improve chronic respiratory health issues through different mechanisms, with inconsistent evidence. By quantitatively summarizing existing studies, our purpose is to determine the connection between greenness exposure and various chronic respiratory health.

Methods

We conducted a comprehensive search on PubMed, EMBASE, and Web of Science core databases to identify relevant studies on the correlation between greenness exposure and chronic respiratory health issues. Studies published up to January 2023 were included in the search. The study used the most frequent indicator (normalized difference vegetation index [NDVI]) as the definition of greenness exposure.

Results

We finally identified 35 studies for meta-analysis. We calculated pooled effects across studies using a random-effects model and conducted a subgroup analysis by age and buffer zones to discuss the effects on chronic respiratory health issues. This study showed that 0.1 increments in NDVI were significantly related to lower rates of asthma incidence, lung cancer incidence, and chronic obstructive pulmonary disease (COPD) mortality risk; the pooled RRs were 0.92 (95% CI: 0.85-0.98), 0.62 (95% CI: 0.40-0.95), and 0.95 (95% CI: 0.92- 0.99), respectively. For the age subgroup, the higher greenness exposure level was related to the incidence rate of asthma among teenagers aged 13-18years (RR: 0.91; 95% CI: 0.83-0.99). For the buffer subgroup, a positive relationship with greenness exposure and asthma incidence/prevalence at 200-300m and 800- 1000m buffers, as well as the COPD mortality at 800-1000m buffer, the pooled RRs were 0.92 (95% CI: 0.86-0.98), 0.87 (95% CI: 0.81-0.93), and 0.93 (95% CI: 0.88- 0.98), respectively. Evidence of publication bias was not detected in this study.

Discussion

Our study is the first global meta-analysis between greenness and various CRDs to report an inverse association. Further research is needed in order to determine the effect of greenness exposure on different CRDs. Therefore, when planning for green development, more consideration must be given to public health and green management as intervention measures.

https://www.crd.york.ac.uk/PROSPEROFILES/384029_STRATEGY_20230116.pdf.

Prediction of the number of asthma patients using environmental factors based on deep learning algorithms

BACKGROUND

Air pollution, weather, pollen, and influenza are typical aggravating factors for asthma. Previous studies have identified risk factors using regression-based and ensemble models. However, studies that consider complex relationships and interactions among these factors have yet to be conducted. Although deep learning algorithms can address this problem, further research on modeling and interpreting the results is warranted.

METHODS

In this study, from 2015 to 2019, information about air pollutants, weather conditions, pollen, and influenza were utilized to predict the number of emergency room patients and outpatients with asthma using recurrent neural network, long short-term memory (LSTM), and gated recurrent unit models. The relative importance of the environmental factors in asthma exacerbation was quantified through a feature importance analysis.

RESULTS

We found that LSTM was the best algorithm for modeling patients with asthma. Our results demonstrated that influenza, temperature, PM10, NO2, CO, and pollen had a significant impact on asthma exacerbation. In addition, the week of the year and the number of holidays per week were an important factor to model the seasonality of the number of asthma patients and the effect of holiday clinic closures, respectively.

CONCLUSION

LSTM is an excellent algorithm for modeling complex epidemiological relationships, encompassing nonlinearity, lagged responses, and interactions. Our study findings can guide policymakers in their efforts to understand the environmental factors of asthma exacerbation.

Impacts of residential indoor air quality and environmental risk factors on adult asthma-related health outcomes in Chicago, IL

BACKGROUND

Residential environments are known to contribute to asthma.

OBJECTIVE

To examine the joint impacts of exposures to residential indoor and outdoor air pollutants and housing risk factors on adult asthma-related health outcomes.

METHODS

We analyzed >1-year of data from 53 participants from 41 homes in the pre-intervention period of the Breathe Easy Project prior to ventilation and filtration retrofits. Health outcomes included surveys of asthma control, health-related quality of life, stress, and healthcare utilizations. Environmental assessments included quarterly measurements of indoor and outdoor pollutants (e.g., HCHO, CO, CO2, NO2, O3, and PM), home walk-throughs, and surveys of environmental risk factors. Indoor pollutant concentrations were also matched with surveys of time spent at home to estimate indoor pollutant exposures.

RESULTS

Cross-sectional analyses using mixed-effects models indicated that lower annual average asthma control test (ACT) scores were associated (p < 0.05) with higher indoor NO2 (concentration/exposure: β = -2.42/-1.57), indoor temperature (β = -1.03 to -0.94), and mold/dampness (β = -3.09 to -2.41). In longitudinal analysis, lower ACT scores were also associated (p < 0.05) with higher indoor NO2 concentrations (β = -0.29), PM1 (concentration/exposure: β = -0.12/-0.24), PM2.5 (concentration/exposure: β = -0.12/-0.26), and PM10 (concentration/exposure: β = 10.14/-0.28). Emergency department visits were associated with poorer asthma control [incidence rate ratio (IRR) = 0.84; p < 0.001], physical health (IRR = 0.95; p < 0.05), mental health (IRR = 0.95; p < 0.05), higher I/O NO2 ratios (IRR = 1.30; p < 0.05), and higher indoor temperatures (IRR = 1.41; p < 0.05).

SIGNIFICANCE

Findings suggest that residential risk factors, including indoor air pollution (especially NO2 and particulate matter), higher indoor temperature, and mold/dampness, may contribute to poorer asthma control.

IMPACT

This study highlights the importance of residential indoor air quality and environmental risk factors for asthma control, health-related quality of life, and emergency department visits for asthma. Two timescales of mixed models suggest that exposure to indoor NO2 and particulate matter, higher indoor temperature, and mold/dampness was associated with poorer asthma control. Additionally, emergency department visits were associated with poorer asthma control and health-related quality of life, as well as higher I/O NO2 ratios and indoor temperatures. These findings deepen our understanding of the interrelationships between housing, air quality, and health, and have important implications for programs and policy.

The modification of air particulate matter on the relationship between temperature and childhood asthma hospitalization: An exploration based on different interaction strategies

The influence of temperature on childhood asthma was self-evident, yet the issue of whether the relationship will be synergized by air pollution remains unclear. The study aimed to investigate whether the relationship between short-term temperature exposure and childhood asthma hospitalization was modified by particulate matter (PM). Data on childhood asthma hospitalization, meteorological factors, and air pollutants during 2013-2016 in Hefei, China, were collected. First, a basic Poisson regression model combined with a distributed lag nonlinear model was used to assess the temperature-childhood asthma hospitalization relationship. Then, two interactive strategies were applied to explore the modification effect of PM on the temperature-childhood asthma hospitalization association. We found a greater effect of cold (5th percentile of temperature) on asthma during days with higher PM_2.5 (RR: 2.16, 95% CI: 1.38, 3.38) or PM₁₀ (RR: 1.87, 95% CI:1.20, 2.91) than that during days with lower PM_2.5 (RR: 1.64, 95% CI: 1.06, 2.54) or PM₁₀ (RR: 1.52, 95% CI: 0.98, 2.36). In addition, we observed a greater modification effect of PM_2.5 on the cold-asthma association than did PM₁₀, with a per 10 μg/m³ increase in PM_2.5 and PM₁₀ associated with increases of 0.065 and 0.025 for the RR corresponding to the 5th temperature percentile, respectively. For the temperature-related AF, moderate cold showed the largest change magnitude with the PM levels rising compared with other temperature ranges. For the subgroup, Females and those aged 6-18 years were more sensitive to the modification effect of PM_2.5 or PM₁₀ on the cold-asthma association. Our findings demonstrated that particulate matter could modify the associations between temperature and childhood asthma hospitalization.

Retrofitting home insulation reduces incidence and severity of chronic respiratory disease

To assess whether retrofitting home insulation can reduce the risk of respiratory disease incidence and exacerbation, a retrospective cohort study was undertaken using linked data from a national intervention program. The study population was made up of 1 004 795 residents from 205 001 New Zealand houses that received an insulation subsidy though a national Energy Efficiency and Conservation Authority program. A difference-in-difference model compared changes in the number of prescriptions dispensed for respiratory illness post- insulation to a control population over the same timeframe. New prescribing of chronic respiratory disease medication at follow-up was used to compare incidence risk ratios between intervention and control groups. Chronic respiratory disease incidence was significantly lower in the intervention group at follow-up: odds ratio 0.90 (95% CI: 0.86-0.94). There was also a 4% reduction in medication dispensed for treating exacerbations of chronic respiratory disease symptoms in the intervention group compared with the control group: relative rate ratio (RRR) 0.96 (95% CI: 0.96-0.97). There was no change in medication dispensed to prevent symptoms of chronic respiratory disease RRR: 1,00 (95% CI: 0.99-1.00). These findings support home insulation interventions as a means of improving respiratory health outcomes.

Retrofitting home insulation reduces incidence and severity of chronic respiratory disease

To assess whether retrofitting home insulation can reduce the risk of respiratory disease incidence and exacerbation, a retrospective cohort study was undertaken using linked data from a national intervention program. The study population was made up of 1 004 795 residents from 205 001 New Zealand houses that received an insulation subsidy though a national Energy Efficiency and Conservation Authority program. A difference-in-difference model compared changes in the number of prescriptions dispensed for respiratory illness post- insulation to a control population over the same timeframe. New prescribing of chronic respiratory disease medication at follow-up was used to compare incidence risk ratios between intervention and control groups. Chronic respiratory disease incidence was significantly lower in the intervention group at follow-up: odds ratio 0.90 (95% CI: 0.86-0.94). There was also a 4% reduction in medication dispensed for treating exacerbations of chronic respiratory disease symptoms in the intervention group compared with the control group: relative rate ratio (RRR) 0.96 (95% CI: 0.96-0.97). There was no change in medication dispensed to prevent symptoms of chronic respiratory disease RRR: 1,00 (95% CI: 0.99-1.00). These findings support home insulation interventions as a means of improving respiratory health outcomes.

Non-optimum ambient temperature may decrease pulmonary function: A longitudinal study with intensively repeated measurements among asthmatic adult patients in 25 Chinese cities

BACKGROUND

Non-optimum ambient temperature has not been widely perceived as an important environmental risk factor for asthma, and the association between ambient temperature and pulmonary function is rarely explored. Our study aimed to investigate the associations between non-optimum ambient temperature and pulmonary function among asthmatic adult patients.

METHODS

We performed a longitudinal study among 4,992 eligible adult asthmatic patients in 25 cities of China from 2017 to 2020. The patients were required to complete pulmonary function test every day in the morning and evening. Linear mixed-effects models and distributed lag non-linear models were used to evaluate the associations between ambient temperature and pulmonary function.

RESULTS

We evaluated 298,396 records of pulmonary function tests. We found inversely J-shaped exposure-response relationship curves for ambient temperature and pulmonary function. The effects of extreme low temperature occurred at lag 0 h and vanished at lag 72 h (almost 3 days). Compared with referent temperature (29.5 °C), extreme low temperature (-9.4 °C) was associated with decreases of 60.4 mL in FEV₁, 299.7 mL/s in PEF, and 101.5 mL in FVC. Extreme high temperature (34.2 °C) was associated with decreases of 26.0 mL in FEV₁, 35.8 mL/s in PEF, and 23.4 mL in FVC. Patients of male, overweight, and elder ages were vulnerable populations, and cold effects were more prominent in the south and in areas without central heating.

CONCLUSIONS

Both extreme low and high ambient temperatures were associated with decreased pulmonary function in adult asthmatic patients. The effect could last for almost 3 days and low temperature was more harmful.

Climatic factors are associated with asthma prevalence: An ecological study using English quality outcomes framework general practitioner practice data

Asthma is a complex disease with multiple environmental factors proposed to contribute to aetiology. Geographical analyses can shed light on the determinants of asthma. Ultraviolet radiation has been associated with asthma prevalence in past ecological studies. We have increased the detail of examining the association between asthma and ultraviolet radiation with addition of the variables of temperature, relative humidity and precipitation. An ecological study was designed to investigate meteorological factors associated with asthma prevalence in England. Data from the 2005 quality outcomes framework were used to determine the prevalence of asthma in primary care in England. This information was supplemented with indicators of obesity and smoking of the General Practitioner practice and population (by age and sex), deprivation and ethnicity at lower super output level from the 2001 and 2011 census. Annual mean meteorological data was attained from the Met Office and Joint Research Centre. We used a multiple linear regression to examine individual and multiple climatic factors through a principal components analysis. We tested for an association with asthma prevalence, after taking into account the spatial autocorrelation of the data. Asthma prevalence from general practice surgeries in England was 5.88% (95% CI 5.83 to 5.92). In the highest ultraviolet radiation weighted by the pre-vitamin D action spectrum (UV_vitd) quartile (2.12 to 2.50 kJ/m²/day), asthma had a 5% reduction in prevalence; compared to the lowest quartile here (0.95 (95% CI 0.92 to 0.98)). Similar reductions were found in the higher temperature 0.93 (95% CI 0.90 to 96). The opposite was found with relative humidity 1.09 (95% CI 1.05 to 1.12). A combination of high temperature and UVvitd highlighted postcode districts in the South East of England with a climate beneficial to low asthma prevalence. The South West of England represented a climate which had both beneficial and detrimental associations with asthma development. Climate is associated with asthma prevalence in England. Understanding the contribution of multiple climatic factors and the relationship with the indoor environment could help to explain the population distribution of asthma.

Prevalence and risk factors for asthma, rhinitis, eczema, and atopy among preschool children in an Andean city

Background

Limited data are available on prevalence and associated risk factors for atopy and allergic diseases from high-altitude urban settings in Latin America.

Objective

To estimate the prevalence of atopy, asthma, rhinitis, and eczema, and associations with relevant risk factors in preschool children in the Andean city of Cuenca.

Methods

A cross-sectional study was undertaken using a representative sample of 535 children aged 3–5 years attending 30 nursery schools in the city of Cuenca, Ecuador. Data on allergic diseases and risk factors were collected by parental questionnaire. Atopy was measured by skin prick test (SPT) reactivity to a panel of relevant aeroallergens. Associations between risk factors and the prevalence of atopy and allergic diseases were estimated using multivariable logistic regression.

Results

Asthma symptoms were reported for 18% of children, rhinitis for 48%, and eczema for 28%, while SPT reactivity was present in 33%. Population fractions of asthma, rhinitis, and eczema attributable to SPT were 3.4%, 7.9%, and 2.9%, respectively. In multivariable models, an increased risk of asthma was observed among children with a maternal history of rhinitis (OR 1.85); rhinitis was significantly increased in children of high compared to low socioeconomic level (OR 2.09), among children with a maternal history of rhinitis (OR 2.29) or paternal history of eczema (OR 2.07), but reduced among children attending daycare (OR 0.64); eczema was associated with a paternal history of eczema (OR 3.73), and SPT was associated with having a dog inside the house (OR 1.67).

Conclusions

A high prevalence of asthma, rhinitis, and eczema symptoms were observed among preschool children in a high-altitude Andean setting. Despite a high prevalence of atopy, only a small fraction of symptoms was associated with atopy. Parental history of allergic diseases was the most consistent risk factor for symptoms in preschool children.

High and low temperatures aggravate airway inflammation of asthma: Evidence in a mouse model

Epidemiology suggests ambient temperature is the triggers and potential activator of asthma. The role of high and low temperatures on airway inflammation of asthma, and the underlying molecular mechanism are not yet understood. A mouse model of asthma was adopted in our experiment. The BALB/c mice were exposed at different temperature for 4 h (2 h in the morning and 2 h in the afternoon) on weekday. The exposure temperatures were 10 °C, 24 °C and 40 °C. Ovalbumin (OVA) was used to sensitize the mice on days 14, 18, 22, 26, and 30, followed by an aerosol challenge for 30 min from day 32-38. After the final OVA challenge, lung function, serum protein and pulmonary inflammation were assessed. Comparing the OVA with the saline group at 24 °C, we saw a significant increase in: serum Total-IgE (p < 0.05); OVA-sIgE (p < 0.01); IL-4 (p < 0.05); IL-1β (p < 0.01); IL-6 (p < 0.01); TNF-α (p < 0.01); and the ratio of IL-4/IFN-γ (p < 0.01). At the same time, there was a significant decrease in IFN-γ (p < 0.01). As the temperature increase, there is a U shape for immune proteins and pro-inflammatory factors with a peak value at 24 °C, exception for IFN-γ (inverted U-shape). After the high and low temperature exposure, the Ri and Re increased significantly, while Cldyn decreased significantly compared with the 24 °C group. Histopathological analysis of the OVA groups showed airway remodeling, airway wall thickening and deforming, and subepithelial fibrosis. More obvious changes were found in the high and low temperature exposure groups. The immunohistochemistry suggested that TRPs changed with temperatures. High and low temperatures can aggravate airway inflammation in a mouse model of asthma. TRPs play an important role in temperature aggravation of allergic asthma. The results suggest that asthmatics should avoid exposure to high and low temperatures for too long time.

Geostatistical predictive modeling for asthma and chronic obstructive pulmonary disease using socioeconomic and environmental determinants

The spatial distribution of the prevalence of asthma and chronic obstructive pulmonary disease (COPD) remains under the influence of a wide array of environmental, climatic, and socioeconomic determinants. However, a large proportion of these influences remain unexplained. In completion, this study examined the spatial associations between asthma/COPD morbidity and their determinants using ordinary least squares (OLS) and geographically weighted regressions (GWR). Inpatient records collected from the secondary and tertiary care hospitals in Kandy from 2010 to 2014 were considered as the dependent variable. Potential risk factors (explanatory variables) were identified in four distinguished classes: 1) meteorological factors, (2) direct and indirect factors of air pollution, (3) socioeconomic factors, and (4) characteristics of the physical environment. All possible combinations of candidate explanatory variables were evaluated through an exploratory regression. A comparison between the regression models was also explored. The best OLS regression models revealed about 55% of asthma variation and 62% of COPD variation while GWR models yielded 78% and 74% of the variation of asthma and COPD occurrences respectively. Relative humidity, proximity to roads (0-200 m), road density, use of firewood as a source of fuel, and elevation play a vital role in predicting morbidity from asthma and COPD. Both local and global regression models are important in assessing spatial relationships of asthma and COPD. However, the local models exhibit a better prediction capability for assessing non-stationary relationships of asthma and COPD than global models. The geostatistical aspects used in this study may also provide insights for evaluating heterogeneous environmental risk factors in other epidemiological studies across different spatial settings.

Essential oils, asthma, thunderstorms, and plant gases: a prospective study of respiratory response to ambient biogenic volatile organic compounds (BVOCs)

Purpose: Prevailing opinion is that wind-pollinated plants affect asthma negatively and that insect- pollinated ones do not. "Thunderstorm" asthma, too, is attributed to bursting grass pollens. Additional biogenic volatile organic compounds (BVOCs) are identified here. Essential oils' BVOCs are inhaled from plants, oil diffusers, candles, room "fresheners", perfumes, and hygiene products. Claims of BVOC "safety" for sensitive respiratory systems are questioned. Methods: Fourteen volunteers, of mixed-age and gender, with seasonal asthma recorded peak expiratory flow (PEF) and 11 symptom scores. BVOCs were collected on Tenax tubes from ambient air in autumn and spring, as were live flower emissions, before and after a thunderstorm. Gas chromatography-mass spectrometry analysis identified frequently occurring BVOCs. Air spora, meteorological, outdoor air pollution variables, and BVOCs predict respiratory symptoms in univariate linear regression models, seasonally. Results: Increased pinene, camphor, linalool, linalyl acetate, benzaldehyde, and benzoic acid predict respiratory symptoms, including reduced PEF, and increased nasal congestion; day length, atmospheric pressure and temperature predict symptoms in both seasons, differently; other variables predict a range of symptoms (0.0001≤p≤0.05). Thunder predicts different BVOC emissions in spring, compared to autumn (p≤0.05). An uncut Grevillea flower emitted linalool and hexenal before a storm; the latter is also emitted from cut grass. Increased nitrogen oxides and pinene in autumn may combine to form harmful oxidation products. Conclusion: This research supports BVOCs as contributors to seasonal asthma and allergic rhinitis, and "thunderstorm" asthma. Pinene emissions from Myrtaceae species (Eucalyptus, Melaleuca, Leptospermum, Callistemon), Brassicaceae (canola), and conifers, worldwide, may induce respiratory inflammation and maintain it, by inhibiting eosinophilic apoptosis. Widely used essential oil products containing BVOCs, like linalool, are associated here with respiratory symptoms. Lagged responses suggest that users' cognitive associations between exposure and response are unlikely, increasing potential for impaired health for vulnerable children.

House Dust Mite Allergy Under Changing Environments

Environmental variations induced by industrialization and climate change partially explain the increase in prevalence and severity of allergic disease. One possible mechanism is the increase in allergen production leading to more exposure and sensitization in susceptible individuals. House dust mites (HDMs) are important sources of allergens inducing asthma and rhinitis, and experimentally they have been demonstrated to be very sensitive to microenvironment modifications; therefore, global or regional changes in temperature, humidity, air pollution or other environmental conditions could modify natural HDM growth, survival and allergen production. There is evidence that sensitization to HDMs has increased in some regions of the world, especially in the subtropical and tropical areas; however, the relationship of this increase with environmental changes is not so clear as has reported for pollen allergens. In this review, we address this point and explore the effects of current and predicted environmental changes on HDM growth, survival and allergen production, which could lead to immunoglobulin E (IgE) sensitization and allergic disease prevalence. We also assess the role of adjuvants of IgE responses, such as air pollution and helminth infections, and discuss the genetic and epigenetic aspects that could influence the adaptive process of humans to drastic and relatively recent environmental changes we are experiencing.

Meteorological parameters and pollutants on asthma exacerbation in Bangalore, India - an ecological retrospective time-series study

BACKGROUND

Literature has shown a significant association between asthma exacerbations and pollutant levels during that time. There is very limited evidence in India, especially Bangalore, for impacts of meteorological changes and pollution on asthma hospital admissions in adults. The objective was to study the impact of air pollution and meteorological parameters on asthma exacerbation in Bangalore.

METHODS

This study quantitatively analyzed the relation between acute exacerbations of asthma and related admissions to the hospital with the air pollution and the meteorological conditions during that time. Data regarding the daily hospital admissions in about 13 tertiary care centers in Bangalore, Karnataka and air pollutant levels and the meteorological conditions prevailing during each day over a year were collected from the Karnataka State pollution control board and meteorology departments, respectively.

RESULTS

An average daily asthma admission of 4.84±2.91, with clear seasonal variation and autocorrelations between meteorological parameters and pollutants was observed. Multiple linear regression analysis revealed that average temperature (p=0.005) and nitrogen dioxide (NO2) (p=0.034) were the two factors that were affecting the number of admissions. Quasi-poisson regression analysis using multi-pollutants and meteorological variables showed that particulate matter and NO2 had significant lag effect for up to 5 days (p<0.05) and rainfall for 1 day (p<0.001).

CONCLUSIONS

In Bangalore city, levels of NO2 and particulate matter, temperature, rainfall, and season increase asthma exacerbations.

Socioeconomic and environmental determinants of adolescent asthma in urban Latin America: an ecological analysis

The prevalence of asthma is high in urban areas of many Latin-American countries where societies show high levels of inequality and different levels of development. This study aimed to examine the relationship between asthma symptoms prevalence in adolescents living in Latin American urban centers and socioeconomic and environmental determinants measured at the ecological level. Asthma prevalence symptoms were obtained from the International Study of Asthma and Allergies in Childhood (ISAAC) phase III. A hierarchical conceptual framework was defined and the explanatory variables were organized in three levels: distal, intermediate, proximal. Linear regression models weighed by sample size were undertaken between asthma prevalence and the selected variables. Asthma prevalence was positively associated with Gini index, water supply and homicide rate, and inversely associated with the Human Development Index, crowding and adequate sanitation. This study provides evidence of the potential influence of poverty and social inequalities on current wheezing in adolescents in a complex social context like Latin America.

Geo-climatic heterogeneity in self-reported asthma, allergic rhinitis and chronic bronchitis in Italy

BACKGROUND

Several studies highlighted a great variability, both between and within countries, in the prevalence of asthma and chronic airways diseases.

AIM

To evaluate if geo-climatic variations can explain the heterogeneity in the prevalence of asthma and respiratory diseases in Italy.

METHODS

Between 2006 and 2010, a postal screening questionnaire on respiratory health was administered to 18,357 randomly selected subjects, aged 20-44, living in 7 centers in northern, central, and southern Italy. A random-effects meta-analysis was fitted to evaluate the between-centers heterogeneity in the prevalence of asthma, asthma-like symptoms, allergic rhinitis, and chronic bronchitis (CB). A principal component analysis (PCA) was performed to synthetize the geo-climatic information (annual mean temperature, range of temperature, annual rainfalls, global solar radiations, altitude, distance from the sea) of all the 110 Italian province capital towns. The associations between these geo-climatic components obtained with PCA and the prevalence of respiratory diseases were analyzed through meta-regression models.

RESULTS

10,464 (57%) subjects responded to the questionnaire. There was a significant between-centers heterogeneity in the prevalence of asthma (I(2)=59.5%, p=0.022) and CB (I(2)=60.5%, p=0.019), but not in that of asthma-like symptoms or allergic rhinitis. Two independent geo-climatic components explaining together about 80% of the overall geo-climatic variability were identified: the first principally summarized the climatic variables; the second the topographic ones. Variations in the prevalence of asthma across centers were significantly associated with differences in the climatic component (p=0.017), but not with differences in the topographic one.

CONCLUSIONS

Our findings suggest that climate play a role in determining the between-center heterogeneity in the prevalence of asthma in Italy, with higher prevalence in dry-hot Mediterranean climates, and lower in rainy-cold northern climates.

Air Pollutants, Climate, and the Prevalence of Pediatric Asthma in Urban Areas of China

Background. Prevalence of childhood asthma varies significantly among regions, while its reasons are not clear yet with only a few studies reporting relevant causes for this variation. Objective. To investigate the potential role of city-average levels of air pollutants and climatic factors in order to distinguish differences in asthma prevalence in China and explain their reasons. Methods. Data pertaining to 10,777 asthmatic patients were obtained from the third nationwide survey of childhood asthma in China's urban areas. Annual mean concentrations of air pollutants and other climatic factors were obtained for the same period from several government departments. Data analysis was implemented with descriptive statistics, Pearson correlation coefficient, and multiple regression analysis. Results. Pearson correlation analysis showed that the situation of childhood asthma was strongly linked with SO2, relative humidity, and hours of sunshine (p < 0.05). Multiple regression analysis indicated that, among the predictor variables in the final step, SO2 was found to be the most powerful predictor variable amongst all (β = -19.572, p < 0.05). Furthermore, results had shown that hours of sunshine (β = -0.014, p < 0.05) was a significant component summary predictor variable. Conclusion. The findings of this study do not suggest that air pollutants or climate, at least in terms of children, plays a major role in explaining regional differences in asthma prevalence in China.

Sparse modeling of spatial environmental variables associated with asthma

Geographically distributed environmental factors influence the burden of diseases such as asthma. Our objective was to identify sparse environmental variables associated with asthma diagnosis gathered from a large electronic health record (EHR) dataset while controlling for spatial variation. An EHR dataset from the University of Wisconsin's Family Medicine, Internal Medicine and Pediatrics Departments was obtained for 199,220 patients aged 5-50years over a three-year period. Each patient's home address was geocoded to one of 3456 geographic census block groups. Over one thousand block group variables were obtained from a commercial database. We developed a Sparse Spatial Environmental Analysis (SASEA). Using this method, the environmental variables were first dimensionally reduced with sparse principal component analysis. Logistic thin plate regression spline modeling was then used to identify block group variables associated with asthma from sparse principal components. The addresses of patients from the EHR dataset were distributed throughout the majority of Wisconsin's geography. Logistic thin plate regression spline modeling captured spatial variation of asthma. Four sparse principal components identified via model selection consisted of food at home, dog ownership, household size, and disposable income variables. In rural areas, dog ownership and renter occupied housing units from significant sparse principal components were associated with asthma. Our main contribution is the incorporation of sparsity in spatial modeling. SASEA sequentially added sparse principal components to Logistic thin plate regression spline modeling. This method allowed association of geographically distributed environmental factors with asthma using EHR and environmental datasets. SASEA can be applied to other diseases with environmental risk factors.

Can meteorological factors forecast asthma exacerbation in a paediatric population?

BACKGROUND

Asthma exacerbations attended in emergency departments show a marked seasonality in the paediatric age. This seasonal pattern can change from one population to another and the factors involved are poorly understood.

OBJECTIVES

To evaluate the association between meteorological factors and schooling with asthma exacerbations in children attended in the paediatric emergency department of a district hospital.

METHODS

We conducted a retrospective review of the medical records of children 5-14 years of age attended for asthma exacerbations during a 4-year period (2007-2011). Climatic data were obtained from a weather station located very close to the population studied. The number of asthma exacerbations was correlated to temperature, barometric pressure, relative humidity, rainfall, wind speed, wind distance, solar radiation, water vapour pressure and schooling, using regression analyses.

RESULTS

During the study period, 371 children were attended for asthma exacerbations; median age was eight years (IQR: 6-11), and 59% were males. Asthma exacerbations showed a bimodal pattern with peaks in spring and summer. Maximum annual peak occurred in week 39, within 15 days from school beginning after the summer holidays. A regression model with mean temperature, water vapour pressure, relative humidity, maximum wind speed and schooling could explain 98.4% (p<0.001) of monthly asthma exacerbations.

CONCLUSIONS

The combination of meteorological factors and schooling could predict asthma exacerbations in children attended in a paediatric emergency department.

Cold spells and the risk of hospitalization for asthma: New York, USA 1991-2006

PURPOSE

A study was conducted to investigate whether prolonged periods of very cold temperatures were associated with an increased risk of hospitalization for asthma.

METHODS

Hospitalization admissions with a principal diagnosis of asthma were identified in New York State, USA, for the months November through April from 1991 to 2006. A cold spell was defined as three or more consecutive days where the daily mean of universal apparent temperature (UAT) within a week prior to admission was at the 10th percentile or less. The percentage change in asthma hospitalizations during and after a cold spell was compared to the average daily number of hospitalizations preceding the cold spell using time series analysis.

RESULTS

The average temperature during winter cold spells (December through March) was -15 °C, compared to -6 and -2 °C for cold spells in November and April, respectively. Cold spells during the winter months were associated with a mean decline of 4.9 % in asthma admissions statewide (95 % CI -7.8, -1.9 %). After a cold spell, no statistically significant changes were apparent during the winter months, but asthma hospitalizations increased after cold spells in the transitional months of November (mean = 9.6, 95 % CI 5.5, 13.9 %) and April (mean = 5.0, 95 % CI 1.2, 9.0 %).

CONCLUSIONS

The results suggest that during prolonged periods of severe cold asthmatics may adhere to medical guidelines and limit their exposure, thereby preventing exacerbations. They may be less likely to alter their behavior in the more moderate months of November and April.

Are children׳s asthmatic symptoms related to ambient temperature? A panel study in Australia

OBJECTIVES

To examine the short-term effects of ambient temperature on respiratory symptoms for school children with asthma across Australia.

METHODS

A panel of 270 children (7-12 years) with asthma was recruited from six Australian cities. They were asked to record their respiratory symptoms every day in the morning (for night-time symptoms) and evening (for daytime symptoms) for four weeks. Daily ambient temperature, relative humidity and air pollution data were obtained from fixed monitors nearby. A mixed logistic regression model was used to examine the effects of ambient temperature on respiratory symptoms adjusted for children's sex, age, standing height, weight and air pollution. Subjects were specified as random effects.

RESULTS

The relationships between ambient temperature and respiratory symptoms were linear. Increasing temperatures induced the risks of children's asthmatic symptoms, especially for "wheeze/chest tightness" and to a lesser extent for "cough/phlegm". The effects were acute and lasted for four days (lag 0-3) in general. With increasing ambient temperature, boys were more at risk than girls.

CONCLUSIONS

High ambient temperature is a risk factor for respiratory symptoms in children with asthma. As ambient temperature increases, policies and strategies for rising temperatures will be necessary to protect asthmatic children.

Effects of meteorological factors on daily hospital admissions for asthma in adults: a time-series analysis

BACKGROUND

There is limited evidence for the impacts of meteorological changes on asthma hospital admissions in adults in Shanghai, China.

OBJECTIVES

To quantitatively evaluate the short-term effects of daily mean temperature on asthma hospital admissions.

METHODS

Daily hospital admissions for asthma and daily mean temperatures between January 2005 and December 2012 were analyzed. After controlling for secular and seasonal trends, weather, air pollution and other confounding factors, a Poisson generalized additive model (GAM) combined with a distributed lag non-linear model were used to explore the associations between temperature and hospital admissions for asthma.

RESULTS

During the study periods, there were 15,678 hospital admissions for asthma by residents of Shanghai, an average 5.6 per day. Pearson correlation analysis found a significant negative correlation (r = -0.174, P<0.001) between asthma hospitalizations and daily mean temperature (DMT). The DMT effect on asthma increased below the median DMT, with lower temperatures associated with a higher risk of hospital admission for asthma. Generally, the cold effect appeared to be relatively acute, with duration lasting several weeks, while the hot effect was short-term. The relative risk of asthma hospital admissions associated with cold temperature (the 25th percentile of temperature relative to the median temperature) was 1.20 (95% confidence interval [CI], 1.01∼1.41) at lag0-14. However, warmer temperatures were not associated with asthma hospital admissions.

CONCLUSIONS

Cold temperatures may trigger asthmatic attacks. Effective strategies are needed to protect populations at risk from the effects of cold.

Prevalence of asthma symptoms in schoolchildren, and climate in west European countries: an ecologic study

The aim of the present study was to estimate the associations between the prevalence of asthma symptoms in schoolchildren and meteorological variables in west European countries that participated in the International Study of Asthma and Allergies in Children (ISAAC), Phase III 1997-2003. An ecologic study was carried out. The prevalence of asthma was obtained from this study from 48 centers in 14 countries, and meteorological variables from those stations closest to ISAAC centers, together with other socioeconomic and health care variables. Multilevel mixed-effects linear regression models were used. For schoolchildren aged 6-7 years, the prevalence rate of asthma decreased with an increase in mean annual sunshine hours, showed a positive association with rainy weather, and warm temperature, and a negative one with relative humidity and physician density (PD). Current wheeze prevalence was stronger in autumn/winter seasons and decreased with increasing PD. Severe current wheeze decreased with PD. For schoolchildren aged 13-14 years, the prevalence rates of asthma and current wheeze increased with rainy weather, and these rates decreased with increased PD. Current wheeze, as measured by a video questionnaire, was inversely associated with sunny weather, and nurse density. Severe current wheeze prevalence was stronger during autumn/winter seasons, decreased with PD, and indoor chlorinated public swimming pool density, and increased with rainy weather. Meteorological factors, including sunny and rainy weather, and PD may have some effect on the prevalence rates of asthma symptoms in children from west European countries.

Gaining a better understanding of respiratory health inequalities among cities: an ecological case study on elderly males in the larger French cities

Background

In recent years, there have been a growing number of studies on spatial inequalities in health covering a variety of scales, from small areas to metropolitan areas or regions, and for various health outcomes. However, few investigations have compared health status between cities with a view to gaining a better understanding of the relationships between such inequalities and the social, economic and physical characteristics. This paper focuses on disparities in respiratory health among the 55 largest French cities. The aim is to explore the relationships between inter-urban health patterns, city characteristics and regional context, and to determine how far a city’s health status relates to the features observed on different geographical scales.

Methods

We used health data describing hospitalizations for Chronic Obstructive Pulmonary Disease (COPD) as a proxy for respiratory health, and the total number of hospitalizations (overall) as a proxy for general health. This last indicator was used as a benchmark. A large set of indicators relating to socioeconomic, physical and amenity aspects of the cities (urban units) was also constructed. Data were analyzed using linear correlations and multiple linear regression models.

Results

The results suggest that socioeconomic characteristics are major discriminators for inequalities in respiratory health status among urban units. Indeed, once combined to socioeconomic characteristics, only a climate indicator remained significant among the physical indicators. It appeared that the pollution indicators which were significantly correlated with COPD hospitalization rates loosed significance when associated to the socio-economic indicators in a multiple regression. The analysis showed that among the socio-economic indicators, an employment indicator derived at the regional scale, and two indicators reflecting the unequal intra-urban spatial distribution of population according to their education, were the most efficient to describe differences in the respiratory health status of urban units.

Conclusion

In order to design effective urban policies, it is essential to gain a better understanding of the differences among cities in their entirety, rather than solely differences across small urban areas or individuals.

Climate change and allergic disease

Allergies are prevalent throughout the United States and impose a substantial quality of life and economic burden. The potential effect of climate change has an impact on allergic disorders through variability of aeroallergens, food allergens and insect-based allergic venoms. Data suggest allergies (ocular and nasal allergies, allergic asthma and sinusitis) have increased in the United States and that there are changes in allergies to stinging insect populations (vespids, apids and fire ants). The cause of this upward trend is unknown, but any climate change may induce augmentation of this trend; the subspecialty of allergy and immunology needs to be keenly aware of potential issues that are projected for the near and not so distant future.

Urban vs. rural factors that affect adult asthma

In this review, our aim was to examine the influence of geographic variations on asthma prevalence and morbidity among adults, which is important for improving our understanding, identifying the burden, and for developing and implementing interventions aimed at reducing asthma morbidity. Asthma is a complex inflammatory disease of multifactorial origin, and is influenced by both environmental and genetic factors. The disparities in asthma prevalence and morbidity among the world's geographic locations are more likely to be associated with environmental exposures than genetic differences. In writing this article, we found that the indoor factors most consistently associated with asthma and asthma-related symptoms in adults included fuel combustion, mold growth, and environmental tobacco smoke in both urban and rural areas. Asthma and asthma-related symptoms occurred more frequently in urban than in rural areas, and that difference correlated with environmental risk exposures, SES, and healthcare access. Environmental risk factors to which urban adults were more frequently exposed than rural adults were dust mites,high levels of vehicle emissions, and a westernized lifestyle.Exposure to indoor biological contaminants in the urban environment is common.The main risk factors for developing asthma in urban areas are atopy and allergy to house dust mites, followed by allergens from animal dander. House dust mite exposure may potentially explain differences in diagnosis of asthma prevalence and morbidity among adults in urban vs. rural areas. In addition, the prevalence of asthma morbidity increases with urbanization. High levels of vehicle emissions,Western lifestyles and degree of urbanization itself, may affect outdoor and thereby indoor air quality. In urban areas, biomass fuels have been widely replaced by cleaner energy sources at home, such as gas and electricity, but in most developing countries, coal is still a major source of fuel for cooking and heating, particularly in winter. Moreover, exposure to ETS is common at home or at work in urban areas.There is evidence that asthma prevalence and morbidity is less common in rural than in urban areas. The possible reasons are that rural residents are exposed early in life to stables and to farm milk production, and such exposures are protective against developing asthma morbidity. Even so, asthma morbidity is disproportionately high among poor inner-city residents and in rural populations. A higher proportion of adult residents of nonmetropolitan areas were characterized as follows:aged 55 years or older, no previous college admission, low household income, no health insurance coverage, and could not see a doctor due to healthcare service availability, etc. In rural areas, biomass fuels meet more than 70% of the rural energy needs. Progress in adopting modern energy sources in rural areas has been slow. The most direct health impact comes from household energy use among the poor, who depend almost entirely on burning biomass fuels in simple cooking devices that are placed in inadequately ventilated spaces. Prospective studies are needed to assess the long-term effects of biomass smoke on lung health among adults in rural areas.Geographic differences in asthma susceptibility exist around the world. The reason for the differences in asthma prevalence in rural and urban areas may be due to the fact that populations have different lifestyles and cultures, as well as different environmental exposures and different genetic backgrounds. Identifying geographic disparities in asthma hospitalizations is critical to implementing prevention strategies,reducing morbidity, and improving healthcare financing for clinical asthma treatment. Although evidence shows that differences in the prevalence of asthma do exist between urban and rural dwellers in many parts of the world, including in developed countries, data are inadequate to evaluate the extent to which different pollutant exposures contribute to asthma morbidity and severity of asthma between urban and rural areas.

Semistructured black-box prediction: proposed approach for asthma admissions in London

Asthma is a global public health problem and the most common chronic disease among children. The factors associated with the condition are diverse, and environmental factors appear to be the leading cause of asthma exacerbation and its worsening disease burden. However, it remains unknown how changes in the environment affect asthma over time, and how temporal or environmental factors predict asthma events. The methodologies for forecasting asthma and other similar chronic conditions are not comprehensively documented anywhere to account for semistructured noncausal forecasting approaches. This paper highlights and discusses practical issues associated with asthma and the environment, and suggests possible approaches for developing decision-making tools in the form of semistructured black-box models, which is relatively new for asthma. Two statistical methods which can potentially be used in predictive modeling and health forecasting for both anticipated and peak events are suggested. Importantly, this paper attempts to bridge the areas of epidemiology, environmental medicine and exposure risks, and health services provision. The ideas discussed herein will support the development and implementation of early warning systems for chronic respiratory conditions in large populations, and ultimately lead to better decision-making tools for improving health service delivery.

The association between cold spells and pediatric outpatient visits for asthma in Shanghai, China

BACKGROUND

Asthma is a serious global health problem. However, few studies have investigated the relationship between cold spells and pediatric outpatient visits for asthma.

OBJECTIVE

To examine the association between cold spells and pediatric outpatient visits for asthma in Shanghai, China.

METHODS

We collected daily data on pediatric outpatient visits for asthma, mean temperature, relative humidity, and ozone from Shanghai between 1 January 2007 and 31 December 2009. We defined cold spells as four or more consecutive days with temperature below the 5(th) percentile of temperature during 2007-2009. We used a Poisson regression model to examine the impact of temperature on pediatric outpatient visits for asthma in cold seasons during 2007 and 2009. We examined the effect of cold spells on asthma compared with non-cold spell days.

RESULTS

There was a significant relationship between cold temperatures and pediatric outpatient visits for asthma. The cold effects on children's asthma were observed at different lags. The lower the temperatures, the higher the risk for asthma attacks among children.

CONCLUSION

Cold temperatures, particularly cold spells, significantly increase the risk of pediatric outpatient visits for asthma. The findings suggest that asthma children need to be better protected from cold effects in winter.

Upper-air observation indicators predict outbreaks of asthma exacerbations among elementary school children: integration of daily environmental and school health surveillance systems in Pennsylvania

OBJECTIVE

To determine whether a relationship exists between asthma exacerbations among elementary school children and daily upper-air observations (temperature, relative humidity, dew point, and mixing ratio) and, if so, to derive a mathematical model that predicts asthma exacerbations among children.

METHODS

Using an ecological study design, school health records of 168,825 elementary school students enrolled in the Health eTools for Schools program within 49 Pennsylvania counties were analyzed. Data representing asthma exacerbations were originally recorded by school nurses as the type of treatment given to a student during a clinic visit on a particular day. Daily upper-air measurements from ground level to the 850 mb pressure level, covering a radius of 800 km around Pittsburgh, PA, were obtained. The Wilcoxon two-sample test was used to identify associations. A generalized estimating equation model was used to predict the occurrence of more than 48 asthma exacerbations, the daily mean for 2008-2010.

RESULTS

Surveillance of asthma among school children in Pennsylvania increased over 3 years. The greatest occurrence was in the fall, followed by summer, spring, and winter. Annual averages of upper-air observations were significantly different between seasons (p < .02). Upper-air temperature, dew point, and mixing ratio above their 3-year mean values and upper-air relative humidity ≥ 50% were significantly associated with occurrence of asthma exacerbations (p < .011).

CONCLUSIONS

Monitoring of upper-air observation data over time can be a reliable means for predicting increases of asthma exacerbations among elementary school children. Such predictions could help parents and school nurses implement effective precautionary measures.

Mite exposure in a Spanish Mediterranean region

BACKGROUND

Knowledge of the domestic mite fauna and allergen levels is important for a correct diagnosis and treatment of mite allergy. Our objectives were to describe the domestic mite fauna in the region of Murcia, Spain, to quantify mite allergens in dust samples obtained from mattresses of this area and to assess the influence of geographical, climatic and dwelling factors.

METHODS

Dust samples were collected in a transversal descriptive study from mattresses of 51 patients who went to the Allergology Service, and from mattress of 81 neighbours or family members of these patients. A questionnaire about home environment was filled in and obtained by all participants. Mite identification was done by light microscopy and allergen determinations (Der p 1 and Der f 1) by monoclonal antibodies.

RESULTS

Sixteen mite species were identified in the 132 dust samples collected. The most frequent species were Dermatophagoides farinae (36% of the samples), Dermatophagoides pteronyssinus (32%) and Tyrophagus putrescentiae (5.3%). There were significant differences among climatic regions. The coastal sector had greater mite abundance, being D. pteronyssinus more frequent and abundant than D. farinae. In inland areas D. farinae was the predominant mite species. Allergen levels correlated with the concentration of Dermatophagoides, with higher levels detected in coastal regions. Average annual temperature was the main outdoor factor that correlated with higher mite concentrations. Indoor main predictor of higher levels of mites was the presence of obvious signs of humidity in the home.

CONCLUSION

This study demonstrates the existence of a mite fauna dominated by D. pteronyssinus and D. farinae with a strong influence of climatic factors and residential characteristics.

Anthropogenic Climate Change and Allergic Diseases

Climate change is expected to have an impact on various aspects of health, including mucosal areas involved in allergic inflammatory disorders that include asthma, allergic rhinitis, allergic conjunctivitis and anaphylaxis. The evidence that links climate change to the exacerbation and the development of allergic disease is increasing and appears to be linked to changes in pollen seasons (duration, onset and intensity) and changes in allergen content of plants and their pollen as it relates to increased sensitization, allergenicity and exacerbations of allergic airway disease. This has significant implications for air quality and for the global food supply.

Impact of meteorological variation on hospital visits of patients with tree pollen allergy

Background

Climate change could affect allergic diseases, especially due to pollen. However, there has been no epidemiologic study to demonstrate the relationship between meteorological factors, pollen, and allergic patients. We aimed to investigate the association between meteorological variations and hospital visits of patients with tree pollen allergy.

Methods

The study subjects were adult patients who received skin prick tests between April and July from 1999 to 2008. We reviewed the medical records for the test results of 4,715 patients. Patients with tree pollen allergy were defined as those sensitized to more than 1 of 12 tree pollen allergens. We used monthly means of airborne tree pollen counts and meteorological factors: maximum/average/minimum temperature, relative humidity, and precipitation. We analyzed the correlations between meteorological variations, tree pollen counts, and the patient numbers. Multivariable logistic regression analyses were used to investigate the associations between meteorological factors and hospital visits of patients.

Results

The minimum temperature in March was significantly and positively correlated with tree pollen counts in March/April and patient numbers from April through July. Pollen counts in March/April were also correlated with patient numbers from April through July. After adjusting for confounders, including air pollutants, there was a positive association between the minimum temperature in March and hospital visits of patients with tree pollen allergy from April to July(odds ratio, 1.14; 95% CI 1.03 to 1.25).

Conclusions

Higher temperatures could increase tree pollen counts, affecting the symptoms of patients with tree pollen allergy, thereby increasing the number of patients visiting hospitals.

Environmental justice and health: a study of multiple environmental deprivation and geographical inequalities in health in New Zealand

There is an increasing interest in the unequal socio-spatial distribution of environmental 'goods' and 'bads' and the associated implications for geographical inequalities in health. Until recently, research in this area has focused on solitary environmental characteristics and has been hindered by the absence of geographically-specific measures that recognise the multifactorial nature of the physical environment. However, recent work in the United Kingdom has developed an area-level multivariate index of health-related physical environmental deprivation that captures both pathogenic and salutogenic environmental characteristics. Applications of this index have demonstrated that, at the national level, multiple environmental deprivation increased as the degree of income deprivation rose. Further, after adjusting for key confounders, there was a significant association between multiple environmental deprivation and the health outcomes of local residents. In the current study we tested the methods developed in the UK to create the New Zealand Multiple Environmental Deprivation Index (NZ-MEDIx) for small areas across the country (n = 1860). We considered whether socially disadvantaged places in New Zealand had higher levels of multiple environmental deprivation, and if environmental disadvantage exerted an influence on health after adjustment for key confounders such as socioeconomic status. We found that although neighbourhoods with higher levels of multiple environmental deprivation tended to have greater social disadvantage, this association was not linear. Further, multiple environmental deprivation tended to exert a modest effect on health that was independent of the age, sex and socioeconomic structure of the population. These findings demonstrate that it is possible to develop an index of multiple environmental deprivation in an alternative national context which has utility in epidemiological investigations.

Sunny hours and variations in the prevalence of asthma in schoolchildren according to the International Study of Asthma and Allergies (ISAAC) Phase III in Spain

The objective of this study was to estimate the relationship between the prevalence of asthma in schoolchildren aged 6-7 years and 13-14 years and the mean annual sunny hours (MASH) in Spain, and to explore predictive models for asthma prevalence. The prevalence of asthma was obtained from the International Study of Asthma and Allergies (ISAAC) Phase III 2002-2003, and climate and socio-economic variables from official sources. Nine centres were studied and a further four centres, two of which are in ISAAC, to test the predictive models. Logistic regression was used to estimate adjusted prevalence rates of asthma for each centre, and multiple regression models to study the effects of MASH and other meteorological and socio-economic variables. The adjusted prevalence rate of asthma decreased 0.6% [95% confidence interval (CI) 0.4-0.8%] for the 6-7 years group and 1.1% (95% CI 0.8-1.3%) for the 13-14 years group with an increase in the MASH of 100 h. Relative humidity was negatively associated with asthma in the older age group, and gross province product per capita (GPP) was positively associated with asthma in the younger age group. The predictive models, which included MASH, gender, relative humidity, and GPP, anticipated prevalence rates of asthma without significant differences between the levels observed and those expected in 9 of the 11 measurements carried out. The results indicate that sunny hours have a protective effect on the prevalence of asthma in schoolchildren.

Possible role of climate changes in variations in pollen seasons and allergic sensitizations during 27 years

BACKGROUND

Climate changes may affect the quality and amount of airborne allergenic pollens. The direct assessment of such an effect requires long observation periods and a restricted geographic area.

OBJECTIVE

To assess variations in pollens and allergic sensitizations across 27 years in relation to climate change in a specific region.

METHODS

We recorded pollen counts, season durations, and prevalences of sensitizations for 5 major pollens (birch, cypress, olive, grass, and Parietaria) in western Liguria between 1981 and 2007. Pollen counts were performed using a Hirst-type trap, and sensitizations were assessed by means of skin prick testing. Meteorologic data for the same period included average temperatures, direct radiation, humidity, number of sunny days, and rainfall.

RESULTS

There was a progressive increase in the duration of the pollen seasons for Parietaria (+85 days), olive (+18 days), and cypress (+18 days), with an overall advance of their start dates. For Parietaria, there was an advance of 2 months in 2006 vs 1981. Also, the total pollen load progressively increased for the considered species (approximately 25% on average) except for grasses. Percentages of patients sensitized to the pollens increased throughout the years, whereas the percentage of individuals sensitized to house dust mite remained stable. These behaviors paralleled the constant increase in direct radiation, temperature, and number of days with a temperature greater than 30 degrees C.

CONCLUSION

The progressive climate changes, with increased temperatures, may modify the global pollen load and affect the rate of allergic sensitization across long periods.

Geo-climate effects on asthma and allergic diseases in adults in Turkey: results of PARFAIT study

The aim of the study was to evaluate the role of geo-climatic factors on the prevalence of allergic diseases in the adult population in Turkey. A total of 25,843 questionnaires using data from parents of 25,843 primary schoolchildren from 14 cities were evaluated. Mean annual temperature was significantly associated with the prevalence of asthma and wheezing in both sexes [respectively; OR: 1.008 (95% CI: 1.003-1.011) and OR: 1.012 (1.006-1.018 in males), OR: 1.007 (1.003-1.012) and OR: 1.01 (1.002-1.018) in females]. In addition, it was associated with eczema in females [OR: 1.007 (1.001-1.012)]. Asthma in females was associated with mean annual humidity in the air [OR: 1.001 (1.000-1.002)]. Annual number of days with snow is associated with wheezing in both sexes [respectively, OR: 1.001 (1.000-1.002) in males and OR: 1.002 (1.000-1.003) in females]. Protective measures could come into priority in certain areas of the country. Allergic diseases may increase as a cause of climate change in the future.

Climate change and emergency medicine: impacts and opportunities

There is scientific consensus that the climate is changing, that human activity plays a major role, and that the changes will continue through this century. Expert consensus holds that significant health effects are very likely. Public health and health care systems must understand these impacts to properly pursue preparedness and prevention activities. All of medicine will very likely be affected, and certain medical specialties are likely to be more significantly burdened based on their clinical activity, ease of public access, public health roles, and energy use profiles. These specialties have been called on to consider the likely impacts on their patients and practice and to prepare their practitioners. Emergency medicine (EM), with its focus on urgent and emergent ambulatory care, role as a safety-net provider, urban concentration, and broad-based clinical mission, will very likely experience a significant rise in demand for its services over and above current annual increases. Clinically, EM will see amplification of weather-related disease patterns and shifts in disease distribution. In EM's prehospital care and disaster response activities, both emergency medical services (EMS) activity and disaster medical assistance team (DMAT) deployment activities will likely increase. EM's public health roles, including disaster preparedness, emergency department (ED)-based surveillance, and safety-net care, are likely to face increasing demands, along with pressures to improve fuel efficiency and reduce greenhouse gas emissions. Finally, EM's roles in ED and hospital management, particularly related to building and purchasing, are likely to be impacted by efforts to reduce greenhouse gas emissions and enhance energy efficiency. Climate change thus presents multiple clinical and public health challenges to EM, but also creates numerous opportunities for research, education, and leadership on an emerging health issue of global scope.

Socio-environmental conditions and geographical variability of asthma prevalence in Northeast Brazil

BACKGROUND

This study aims to evaluate the association between environmental and socio-economic conditions with asthma prevalence in the eight ISAAC centres in North-East Brazil.

METHODS

Estimates on occurrence, severity and medical diagnoses of asthma in the previous 12 months were compared using environmental and socioeconomic indicators. Associations were assessed using simple linear regression and Pearson correlation coefficient.

RESULTS

There was no difference in asthma prevalence between centres. Active asthma prevalence increased with increasing water privation, and this would explain 62 % of the observed prevalence. Median temperature increase was inversely related to active asthma (r=0.81; p<0.05). There was a positive association between latitude and active asthma prevalence (r=0.82; p<0.005), a negative association between severe asthma and yearly medium temperature (r=-0.89; p<0.05), and a positive association with latitude (r=0.78; p<0.05).

CONCLUSION

Relation between the tropical weather and high prevalence of asthma was not confirmed. There were associations with water privation and latitude.

Influence of two different geo-climatic zones on the prevalence and time trends of asthma symptoms among Spanish adolescents and schoolchildren

Few studies have focused on the long-term influence of the climate on the prevalence of asthma. The aim of this study is to establish the influence of geo-climatic conditions on the prevalence of asthma symptoms both in adolescents and schoolchildren, and to discover if this influence is associated with their time trends. Eight centres in Spain performed both ISAAC phases I (1994) and III (2002) in children 13-14 years old. Six of them also surveyed children 6-7 years old. For each age group and phase, about 3,000 children were surveyed per centre. This study examines the prevalence of current wheeze and severe current wheeze in two different geo-climatic zones, coast and plateau, considering their relative humidity and temperature range. In both age groups, the mean asthma prevalence on the coast, for phase I and III, was significantly higher than on the plateau. Living on the plateau was an independent protective factor for current wheeze and severe current wheeze for the two age groups. Within the coastal centres, the increase of the annual relative humidity was a statistical significant risk factor for current wheeze, the same trend existing for current severe wheeze. These effects were independent of the sex and of the phase of the study. The prevalence of asthma and severe asthma symptoms is more frequent on the coast of Spain as compared to the inner plateau. This finding was repeated both in 1994 and in 2002.

Prevalence and risk factors of allergies in Turkey: Results of a multicentric cross-sectional study in children

The Prevalence And Risk Factors of Allergies in Turkey (PARFAIT) study was planned to evaluate prevalence and risk factors of asthma and allergic diseases and also to find out which geographical variables and/or climatic conditions play a role determining the prevalence of allergic diseases in Turkish school children. Study was planned as cross-sectional questionnaire-based. About 25,843 questionnaires from 14 centers were appropriate for analysis. Parental history of allergy, having an atopic sibling and other atopic disease in index case was significant risk factors for all allergic diseases. Breast feeding decreased the risk of current asthma (OR: 0.92, CI: 0.86-0.99) and wheezing (OR: 0.93, CI: 0.87-0.99) but not allergic rhinitis and eczema. Respiratory infection in the past was an important risk factor for the occurrence of allergic diseases especially for asthma which was increased 4.53-fold. Children exposed to household smoke were significantly at higher risk of asthma, wheezing, and allergic rhinitis (OR: 1.20, CI: 1.08-1.33; OR: 1.21, CI: 1.09-1.34; and OR: 1.32, CI: 1.21-1.43, respectively). All allergic diseases were increased in those children living in areas which have altitude of below 1000 m and mean yearly atmospheric pressure above 1000 mb. The study has suggested that household and country-specific environmental factors are associated with asthma, wheezing, allergic rhinitis, and eczema risk during childhood in Turkey.

Asthma exacerbations . 1: epidemiology

Asthma exacerbations may be triggered by a number of atmospheric and domiciliary environmental factors as well as by those encountered in schools and workplaces. The majority of exacerbations, particularly in children, coincide with respiratory viral infections, most commonly rhinovirus. As most respiratory viruses and many aeroallergens appear in seasonal patterns, asthma exacerbations, particularly those requiring emergency treatment, show analogous seasonal cycles which differ in form in children and adults. While similar in form between the sexes, they differ in amplitude, with boys having higher risks of exacerbation in childhood and women in adult life. Simultaneous exposure of asthmatics with respiratory viral infections to allergens or air pollutants may significantly increase the risks of exacerbation. Access to and compliance with inhaled corticosteroid treatment is an important predictor of the likelihood of asthma exacerbations occurring, including those that occur during respiratory viral infections. Epidemiologically, the degree of asthma control achieved by asthmatics is an important predictor of the likelihood of disease exacerbation including respiratory failure, death, and health service consumption.

Seasonality in adult asthma admissions, air pollutant levels, and climate: a population-based study

OBJECTIVE AND BACKGROUND

Most studies of asthma seasonal variations have not examined associations of environmental risk factors and climatic changes associated with seasonality in asthma hospitalizations. This study used population-based data to examine seasonality in asthma admissions and the associated seasonality in levels of air pollutants and climatic factors during a 4-year period in Taiwan.

METHODS

A total of 126,671 asthma hospitalizations in Taiwan during 1998-2001 operationalized as monthly admissions per 100,000 population and monthly mean levels of criterion air pollutants and meteorological factors were subjected to Auto-Regressive Integrated Moving Average to test for seasonality and association between asthma admission rates and the pollutant and climatic factor levels. Owing to significant differences in seasonality between pediatric and adult age groups, this study was limited to 99,591 adult asthma cases to examine the seasonality issue as related to the criterion air pollutants and climatic factors using Spearman rank correlations.

RESULTS

Seasonal trends showed a hospitalization peak in January through March and a sharp decline beginning in April to a trough in June for both sexes. Seasonal variations in adult asthma admissions were significantly positively correlated with levels of PM10, SO2, CO, NO2, and atmospheric pressure and negatively correlated with temperature and hours of sunshine.

CONCLUSIONS

Adult asthma hospitalization propensity is highest in spring and is significantly correlated with air pollution and climate. Air quality control programs and early public warning systems on pollution and atmospheric factors are needed to enable predisposed individuals and their physicians to preempt attacks through primary and secondary preventive measures.

Changing prevalence of asthma in Taiwanese adolescents: two surveys 6 years apart

This study compared the prevalence of asthma among Taiwanese adolescents with individual-level risk factors and municipal-level air pollution and meteorology data to determine whether changes in these factors could explain the observed change in prevalence. We conducted two national surveys of respiratory illness and symptoms in Taiwanese middle-school students in 1995-96 and 2001. The effects of personal and environmental factors were assessed and temporal changes of outdoor monitoring data were also compared with asthma prevalence difference. A total of 44,104 children from the 1995-96 survey and 11,048 children from the 2001 survey attended schools located within 1 km of 22 monitoring stations. Lifetime prevalences of physician-diagnosed and questionnaire-determined asthma increased during this period. After adjustment for potential risk factors, the prevalence differences were statistically unchanged. Although parental education level contributed most, changes in investigated personal and environmental factors might not explain the observed changes in asthma prevalence. Municipalities with higher temperature increase were significantly associated with prevalence difference in questionnaire-determined asthma. We concluded that correlates of the investigated individual-level factors, which have changed over time, still underlie changes in asthma prevalence. Increasing temperature might be the main reason for the rising trends of asthma in Taiwanese adolescents.

Climate and the prevalence of symptoms of asthma, allergic rhinitis, and atopic eczema in children

AIMS

To investigate the association between climate and atopic diseases using worldwide data from 146 centres of the International Study of Asthma and Allergies in Childhood (ISAAC).

METHODS

Between 1992 and 1996, each centre studied random samples of children aged 13-14 and 6-7 years (approx. 3000 per age group and centre) using standardised written and video questionnaires on symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema during the past 12 months. Data on long term climatic conditions in the centres were abstracted from one standardised source, and mixed linear regression models calculated to take the clustering of centres within countries into account.

RESULTS

In Western Europe (57 centres in 12 countries), the prevalence of asthma symptoms, assessed by written questionnaire, increased by 2.7% (95% CI 1.0% to 4.5%) with an increase in the estimated annual mean of indoor relative humidity of 10%. Similar associations were seen for the video questionnaire and the younger age group. Altitude and the annual variation of temperature and relative humidity outdoors were negatively associated with asthma symptoms. The prevalence of eczema symptoms correlated with latitude (positively) and mean annual outdoor temperature (negatively).

CONCLUSIONS

Results suggest that climate may affect the prevalence of asthma and atopic eczema in children.

The role of climate on the geographic variability of asthma, allergic rhinitis and respiratory symptoms: results from the Italian study of asthma in young adults

BACKGROUND

Variations in the prevalence of respiratory symptoms according to geo-climatic factors could provide important clues to the knowledge of the aetiology of asthma.

METHODS

Geo-climatic variations in the prevalence of current asthma, allergic rhinitis and chronic cough, and phlegm were assessed on a random sample of 18 873 subjects (response rate = 72.7%) from different climatic regions of Italy. An ecological analysis, supported by robust statistical methods, was employed to investigate potential trends.

RESULTS

The prevalence of all symptoms was significantly heterogeneous throughout the peninsula. Only asthma-like symptoms showed a north-south trend: the prevalence increased at a decreasing latitude [odds ratio (OR) varies from 0.92 to 0.96, P < 0.05], at a decreasing distance from the sea (OR: 0.90-0.93 for 30 km distance, P < 0.05), at higher annual mean temperatures (OR: 1.11-1.14, P < 0.05) and at smaller annual temperature ranges (OR: 0.94-0.95, P < 0.05). Of the geo-climatic variables considered, temperature range had the greatest influence on most asthma-like symptoms. No association was found between geo-climatic variables and allergic rhinitis or chronic cough and phlegm.

CONCLUSIONS

Asthma prevalence seems to be significantly affected by climate as asthma-like symptoms were more common in central-southern Italy, with a Mediterranean climate, than in areas with a continental climate (northern Italy).

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.

Making health data maps: a case study of a community/university research collaboration

This paper presents the main findings from a collaborative community/university research project in Canada. The goal of the project was to improve access to community health information, and in so doing, enhance our knowledge of the development of community health information resources and community/university collaboration. The project built on a rich history of community/university collaboration in Southeast Toronto (SETO), and employed an interdisciplinary applied research and action design. Specific project objectives were to: (1) develop via active community/university collaboration a geographic information system (GIS) for ready access to routinely collected health data, and to study logistical, conceptual and technical problems encountered during system development; and (2) to document and analyze issues that can emerge in the process of community/university research collaboration. System development involved iteration through community user assessment of need, development or refinement of the GIS, and assessment of the GIS by community users. Collaborative process assessment entailed analysis of archival material, interviews with investigators and participant observation. Over the course of the project, a system was successfully developed, and favorably assessed by users. System development problems fell into four main areas: maintaining user involvement in system development, understanding and integrating data, bringing disparate data sources together, and making use of assembled data. Major themes emerging from the community/university collaborative research process included separate community and university cultures, time as an important issue for all involved, and the impact of uncertainty and ambiguity on the collaborative process.

The impact of climate and traffic-related NO2 on the prevalence of asthma and allergic rhinitis in Italy

BACKGROUND

Environmental factors are likely to be involved in explaining the wide geographical variation in asthma and atopic diseases that has been documented in many recent epidemiological studies.

AIM

To evaluate to what extent climate and outdoor NO2 pollution can explain the geographical variation in the prevalence of asthma and allergic rhinitis, and to estimate the relative risk for exposure to different levels of these two factors.

METHODS

The impact of climate and long-term exposure to nitrogen dioxide (NO2) pollution on asthma and allergic rhinitis was assessed in a cross-sectional study, carried out during 1998 to 2000 on young adults aged 20 to 44 years (n = 18 873), living in 13 areas from two different Italian climatic regions (subcontinental and Mediterranean).

RESULTS

Mediterranean areas had a significantly higher prevalence of asthma-like symptoms (P < 0.001), higher annual mean temperature (16.2 degrees C vs. 12.9 degrees C), lower temperature range (16.0 C degrees vs. 22.1 degrees C) and lower NO2 levels (31.46 microg/m3 vs. 57.99 microg/m3) than subcontinental ones. Mediterranean climate was associated with an increased risk of wheeze (OR = 1.23; 95% CI 1.13 to 1.35), tightness in the chest (OR = 1.21; 95% CI 1.11 to 1.33), shortness of breath (OR = 1.21; 95% CI 1.08 to 1.36) and asthma attacks (OR = 1.19; 95% CI 1.07 to 1.31). After adjusting for climate, an increase of 18.3 microg/m3 in NO2 levels moderately increased the risk of asthma attacks (OR = 1.13; 95% CI 0.98 to 1.32), tightness in the chest (OR = 1.11; 95% CI 0.98 to 1.26) and wheeze (OR = 1.11; 95% CI 0.96 to 1.28). When the levels of outdoor NO2 exposure rose, the prevalence of allergic rhinitis increased significantly in the Mediterranean region (OR = 1.38; 95% CI 1.12 to 1.69), but not in the subcontinental one (OR = 1.03; 95% CI 0.83 to 1.28).

CONCLUSION

Our results show that the prevalence of asthma increases when annual mean temperature increases and temperature range decreases. Furthermore, climate interacts with NO2 outdoor exposure, increasing the risk for allergic rhinitis in people exposed to high stable temperatures. A long-term role for the effect of traffic pollution on asthma is also suggested.