Forecasting the start and severity of the hay fever season

A prospective study evaluating the correlation between local weather conditions, pollen counts and pruritus of dogs with atopic dermatitis

BACKGROUND

Canine atopic dermatitis (cAD) is a hereditary, generally pruritic and predominantly T-cell-driven inflammatory skin disease, involving an interplay between skin barrier abnormalities, allergen sensitisation and microbial dysbiosis. The individual immunological response is predominantly against environmental allergens, including mite antigens; mould spores; and pollen from grasses, trees and weeds. Airborne pollens show fluctuating patterns during the year.

OBJECTIVE

The aim of this prospective study was to evaluate the influence of local pollen concentrations and weather conditions on the clinical signs of atopic dogs, and to investigate any possible correlations with the results of intradermal testing (IDT).

MATERIALS AND METHODS

Thirty-seven privately owned atopic dogs in Bavaria were surveyed from 1 April to 30 November 2021. Owners were asked to record pruritus using a validated Visual Analog Scale (PVAS) score and the weekly medication of their dog. Furthermore, weather data, including pollen count, rainfall, relative humidity, hours of sunshine and temperature from the dog's location were collected daily.

RESULTS

Of the evaluated parameters, only humidity and medication scores correlated positively with the PVAS scores of the atopic dogs. There was no correlation between specific pollen counts and PVAS scores of dogs with positive IDT reactions to that pollen.

CONCLUSION AND CLINICAL RELEVANCE

The outcome of this study highlights the importance of a careful interpretation of positive IDT results in dogs with cAD and questions the validity of airborne pollen trap methodology in representing pollen exposure for dogs at ground level.

Co-exposure to highly allergenic airborne pollen and fungal spores in Europe

The study is aimed at determining the potential spatiotemporal risk of the co-occurrence of airborne pollen and fungal spores high concentrations in different bio-climatic zones in Europe. Birch, grass, mugwort, ragweed, olive pollen and Alternaria and Cladosporium fungal spores were investigated at 16 sites in Europe, in 2005-2019. In Central and northern Europe, pollen and fungal spore seasons mainly overlap in June and July, while in South Europe, the highest pollen concentrations occur frequently outside of the spore seasons. In the coldest climate, no allergy thresholds were exceeded simultaneously by two spore or pollen taxa, while in the warmest climate most of the days with at least two pollen taxa exceeding threshold values were observed. The annual air temperature amplitude seems to be the main bioclimatic factor influencing the accumulation of days in which Alternaria and Cladosporium spores simultaneously exceed allergy thresholds. The phenomenon of co-occurrence of airborne allergen concentrations gets increasingly common in Europe and is proposed to be present on other continents, especially in temperate climate.

Airborne grass pollen and thunderstorms influence emergency department asthma presentations in a subtropical climate

BACKGROUND

Grass pollen is considered a major outdoor aeroallergen source worldwide. It is proposed as a mechanism for thunderstorm asthma that lightning during thunderstorms promotes electrical rupture of pollen grains that leads to allergic airway inflammation. However, most evidence of associations between grass pollen and asthma comes from temperate regions. The objective of this study was to investigate short-term associations between airborne grass pollen exposure and asthma emergency department presentations in a subtropical population.

METHODS

Episode level public hospital presentations for asthma (2016-2020) were extracted for greater Brisbane, Australia, from Queensland Health's Emergency Data Collection. Concentrations of airborne pollen were determined prospectively using a continuous flow volumetric impaction sampler. Daily time series analysis using a generalised additive mixed model were applied to determine associations between airborne grass pollen concentrations, and lightning count data, with asthma presentations.

RESULTS

Airborne grass pollen showed an association with asthma presentations in Brisbane; a significant association was detected from same day exposure to three days lag. Grass pollen exposure increased daily asthma presentations up to 48.5% (95% CI: 12%, 85.9%) in female children. Lightning did not modify the effect of grass pollen on asthma presentations, however a positive association was detected between cloud-to-cloud lightning strikes and asthma presentations (P = 0.048).

CONCLUSION

Airborne grass pollen exposure may exacerbate symptoms of asthma requiring urgent medical care of children and adults in a subtropical climate. This knowledge indicates an opportunity for targeted management of respiratory allergic disease to reduce patient and health system burden. For the first time, an influence of lightning on asthma was detected in this context. The outcomes support a need for continued pollen monitoring and surveillance of thunderstorm asthma risk in subtropical regions.

Ragweed pollen concentration predicts seasonal rhino-conjunctivitis and asthma severity in patients allergic to ragweed

In this work, we investigate the correlation between ragweed pollen concentration and conjunctival, nasal, and asthma symptom severity in patients allergic to ragweed pollen using ambient pollen exposure in the Milan area during the 2014 ragweed season We calculate the pollen/symptom thresholds and we assess the effectiveness of ragweed allergen immunotherapy (AIT). A total of 66 participants allergic to ragweed (Amb a 1) were enrolled in the study and divided into two groups: AIT treated (24) and no AIT treated (42). Pollen counts and daily symptom/medication patient diaries were kept. Autoregressive distributed lag models were used to develop predictive models of daily symptoms and evaluate the short-term effects of temporal variations in pollen concentration on the onset of symptoms. We found significant correlations between ragweed pollen load and the intensity of symptoms for all three symptom categories, both in no AIT treated (τ = 0.341, 0.352, and 0.721; and ρ = 0.48, 0.432, and 0.881; p-value < 0.001) and in AIT treated patients (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau$$\end{document}τ= 0.46, 0.610, and 0.66; and ρ = 0.692, 0.805, and 0.824; p-value < 0.001). In both groups, we observed a positive correlation between the number of symptoms reported and drug use. Mean symptom levels were significantly higher in no AIT treated than in AIT treated patients (p-value < 0.001) for all symptom categories. Pollen concentration thresholds for the four symptom severity levels (low, medium–low, medium–high and high) were calculated. Ragweed pollen concentration is predictive of symptom severity in patients with a ragweed (Amb a 1) allergy. Patients treated with AIT had significantly reduced mean symptom levels compared to those without AIT.

Pollen season trends as markers of climate change impact: Betula, Quercus and Poaceae

The incidences of respiratory allergies are at an all-time high. Pollen aeroallergens can reflect changing climate, with recent studies in Europe showing some, but not all, pollen types are increasing in severity, season duration and experiencing an earlier onset. This study aimed to identify pollen trends in the UK over the last twenty-six years for a range of pollen sites, with a focus on the key pollen types of Poaceae (grass), Betula (birch) and Quercus (oak) and to examine the relationship of these trends with meteorological factors. Betula pollen seasons show no significant trends for onset, first high day or duration but increasing pollen production in the Midlands region of the UK is being driven by warmer temperatures in the previous June and July. Quercus pollen seasons are starting earlier, due to increasing temperature and sunshine totals in April, but are not becoming more severe. The seasons are lasting longer, although no significant climate drivers for this were identified. The first high day of the Poaceae pollen season is occurring earlier in central UK regions due to an increasing trend for all temperature variables in the previous December, January, April, May and June. Severity and duration of the season show no significant trends and are spatially and temporally variable. Important changes are occurring in the UK pollen seasons that will impact on the health of respiratory allergy sufferers, with more severe Betula pollen seasons and longer Quercus pollen seasons. Most of the changes identified were caused by climate drivers of increasing temperature and sunshine total. However, Poaceae pollen seasons are neither becoming more severe nor longer. The reasons for this included a lack of change in some monthly meteorological variables, or land-use change, such as grassland being replaced by urban areas or woodland.

An integrated system for automated measurement of airborne pollen based on electrostatic enrichment and image analysis with machine vision

Here we describe an automated and compact pollen detection system that integrates enrichment, in-situ detection and self-cleaning modules. The system can achieve continuous capture and enrichment of pollen grains in air samples by electrostatic adsorption. The captured pollen grains are imaged with a digital camera, and an automated image analysis based on machine vision is performed, which enables a quantification of the number of pollen particles as well as a preliminary classification into two types of pollen grains. In order to optimize and evaluate the system performance, we developed a testing approach that utilizes an airflow containing a precisely metered amount of pollen particles surrounded by a sheath flow to achieve the generation and lossless transmission of standard gas samples. We studied various factors affecting the pollen capture efficiency, including the applied voltage, air flow rate and humidity. Under optimized conditions, the system was successfully used in the measurement of airborne pollen particles within a wide range of concentrations, spanning 3 orders of magnitude.

Aerobiological modeling I: A review of predictive models

The present work is the first of two reviews on applied modeling in the field of aerobiology. The aerobiological predictive models for pollen and fungal spores, usually defined as predictive statistical models, will, amongst other objectives, forecast airborne particles' concentration or dynamical behavior of the particles. These models can be classified into Observation Based Models (OBM), Phenological Based Models (PHM), or OTher Models (OTM). The aim of this review is to show, analyze and discuss the different predictive models used in pollen and spore aerobiological studies. The analysis was performed on published electronic scientific articles from 1998 to 2016 related to the type of model, the taxa and the modelled parameters. From a total of 503 studies, 55.5% used OBM (44.8% on pollen and 10.7% on fungal spores), 38.5% PHM (all on pollen) and 6% OTM (5.4% on pollen and 0.6% on fungal spores). OBM have been used with high frequency to forecast concentration. The most frequent model of OBM was linear regression (18.5% out of 503) on pollen and artificial neural networks (4.6%) on fungal spores. In the PHM, the principal use was to characterize the main pollen season (flowering season) based on the model of growth degree days. Finally, OTM have been used to estimate concentrations at unmonitored areas. Olea (14,5%) on pollen and Alternaria (4,8%) on fungal spores were the taxa most frequently modelled. Daily concentration was the most modelled parameter by OBM (25.2%) and season start day by PHM (35.6%). The PHM approaches include greater model diversity and use fewer independent variables than OBM. In addition, PHM show to be easier to apply than OBM; however, the wide range of criteria to define the parameters to use in PHM (e.g.: pollination start day) makes that each model is used with a lesser frequency than other models.

Fungal spores and pollen are correlated with meteorological variables: effects in human health at Hermosillo, Sonora, Mexico

We conducted the first study of air pollen and fungal spores for Hermosillo, Sonora, where the human population is exposed to high temperatures and high levels of dust and suffers from diseases related to air quality. We sampled pollen and fungal spores daily in the air during 2016 using a volumetric spore trap Hirst-type sampler. We used simple linear correlation to investigate the association between pollen and spore counts and daily weather conditions. We found an Annual Pollen Integral of 16,243 pollen day/m³ and an Annual Spore Integral higher 222,365 spore day/m³. We identified 32 pollen taxa and 15 different spores. We found two periods of higher pollen and spore concentrations: March to May and August to October, the latter was the most severe. Spore and pollen concentrations in the air increased at higher temperature and higher relative humidity but decreased at higher precipitation. We detected negative impacts during summer and fall on population health, with 13,454 cases of people who presented diseases related to allergies. A peak in allergies is centered during October and correlates well with our peaks in pollen and spore concentrations; it seems that pollen of Poaceae is the one that generates most effects in allergic people.

The Clinical Utility of Pollen Counts

In this review, we describe how pollen counts are performed, the health effects caused by exposure to varying amounts of pollen, the clinical utility of reporting pollen counts to the public, and how that information can be used by patients who have allergies to improve their health. The public is very interested in pollen counts, particularly if the counts provide a forecast of expected pollen exposure for the next few days. Traditional pollen counts are labor-intensive; poorly distributed; and, since the counts are usually 1-day-old, do not provide forecasts that can be acted on. New methods that provide short- and long-term pollen forecasts can provide this information to allergic individuals so that they can respond to changing outdoor conditions. Studies of the relationship between artificial and natural exposure to pollen and development of symptoms have provided improved understanding into how much pollen it takes to cause symptoms. Thresholds for pollen counts that trigger symptoms vary by pollen type, sensitivity of the population, and interactions with other atmospheric exposures. Strategies to inform the public when the pollen count poses a health risk have been proposed along with computerized systems that provide personalized pollen alerts. The best performing public notification system was a "traffic light system" that reported pollen exposure as low, 0-30; intermediate, 31-50; or high, 51-150. This system outperformed other threshold systems used in Sweden and in Britain/Denmark. Continued improvements in pollen forecasting models combined with data provided by automated pollen counters and better public reporting should permit allergic individuals and urban planners to adapt effectively to changes in outdoor aeroallergen exposures.

Grass pollen as a trigger of emergency department presentations and hospital admissions for respiratory conditions in the subtropics: A systematic review

INTRODUCTION

It is unknown if high concentration of airborne grass pollen, where subtropical grasses (Chloridoideae and Panicoideae) dominate, is a risk factor for respiratory health. Here we systematically reviewed the association between airborne grass pollen exposure and asthma emergency department (ED) presentations and hospital admissions in subtropical climates.

OBJECTIVES

A systematic review was performed to identify and summarise studies that reported on respiratory health (asthma ED presentations and hospital admissions) and airborne grass pollen exposure in subtropical climates.

METHODS

Searches were conducted in: MEDLINE, Web of Science, Scopus, CINAHL (EBSCO), Embase and Google Scholar databases (1966-2019). Risk of bias was assessed using a validated quality assessment tool. A meta-analysis was planned, however due to the heterogeneity in study design it was determined inappropriate and instead a narrative synthesis was undertaken.

RESULTS

Nineteen studies were identified for inclusion, with a total of 598,931 asthma ED presentation participants and 36,504 asthma hospital admission participants in six countries (Australia, India, Israel, Italy, Spain, USA). The narrative synthesis found airborne grass pollen appears to have a small and inconsistent increase on asthma ED presentations (judged as: probably little effect n = 5, may have little effect n = 4, no effect n = 2 and uncertain if there is an effect n = 4) and hospital admissions (judged as: probably increase slightly n = 2 probably little effect n = 1, may have a little effect n = 1, no effect n = 3 and we are uncertain if there is an effect n = 4) in the subtropics. Furthermore, the reported effect sizes were small and its clinical relevance may be difficult to discern.

CONCLUSION

Exposure to airborne grass pollen appears to have a small and inconsistent increase on asthma ED presentations and hospital admissions in the subtropics. These findings are comparable to reported observations from studies undertaken in temperate regions.

First allergenic pollen monitoring in Bucharest and results of three years collaboration with European aerobiology specialists

INTRODUCTION

Respiratory allergies induced by allergenic plants pollen represent an important public health problem with increasing prevalence and severity. Aerobiologic study of allergenic pollens is performed in many countries on regular basis and correlated with health data from allergists in the frame of national aerobiology networks. Romania has no aerobiology network and pollen measurements have been done between 1999-2012 in West region only. In the frame of COST Action called Sustainable management of Ambrosia artemisiifolia in Europe (SMARTER FA 1203), three years collaboration with Reseau National de Surveillance Aerobiologique (RNSA) from France and the first pollen monitoring center in Bucharest were established.The aim of this paper is to present results of first pollen monitoring in Bucharest, activities of Romanian SMARTER group and collaboration with European aerobiology specialists.

MATERIAL AND METHOD

We used a Hirst-type pollen trap placed on the roof of the Research Center from "Colentina" Clinical Hospital and the pollen monitoring method based on European Aeroallergen Network (EAN) standardized requirements. Monthly results during the pollen seasons 2014-2016 were sent to RNSA and EAN and posted on the European pollen information site.

RESULTS

We found high amounts of allergenic pollen, mainly grasses from May to September and Ambrosia artemisiifolia during September. Conlcusions. We concluded that SMARTER offered access to aerobiology training, improved multidisciplinary collaboration and perspectives to further develop national and international projects. More coordinated efforts to develop national aerobiology network and to recuperate the gap comparing to other European countries in the field of aerobiology and respiratory allergology are needed.

Climate-change-induced range shifts of three allergenic ragweeds (Ambrosia L.) in Europe and their potential impact on human health

Invasive allergenic plant species may have severe health-related impacts. In this study we aim to predict the effects of climate change on the distribution of three allergenic ragweed species (Ambrosia spp.) in Europe and discuss the potential associated health impact. We built species distribution models based on presence-only data for three ragweed species, using MAXENT software. Future climatic habitat suitability was modeled under two IPCC climate change scenarios (RCP 6.0 and RCP 8.5). We quantify the extent of the increase in 'high allergy risk' (HAR) areas, i.e., parts of Europe with climatic conditions corresponding to the highest quartile (25%) of present day habitat suitability for each of the three species. We estimate that by year 2100, the distribution range of all three ragweed species increases towards Northern and Eastern Europe under all climate scenarios. HAR areas will expand in Europe by 27-100%, depending on species and climate scenario. Novel HAR areas will occur mostly in Denmark, France, Germany, Russia and the Baltic countries, and overlap with densely populated cities such as Paris and St. Petersburg. We conclude that areas in Europe affected by severe ragweed associated allergy problems are likely to increase substantially by year 2100, affecting millions of people. To avoid this, management strategies must be developed that restrict ragweed dispersal and establishment of new populations. Precautionary efforts should limit the spread of ragweed seeds and reduce existing populations. Only by applying cross-countries management plans can managers mitigate future health risks and economical consequences of a ragweed expansion in Europe.

Poaceae pollen in the air depending on the thermal conditions

The relationship between the meteorological elements, especially the thermal conditions and the Poaceae pollen appearance in the air, were analysed as a basis to construct a useful model predicting the grass season start. Poaceae pollen concentrations were monitored in 1991-2012 in Kraków using the volumetric method. Cumulative temperature and effective cumulative temperature significantly influenced the season start in this period. The strongest correlation was seen as the sum of mean daily temperature amplitudes from April 1 to April 14, with mean daily temperature>15 °C and effective cumulative temperature>3 °C during that period. The proposed model, based on multiple regression, explained 57% of variation of the Poaceae season starts in 1991-2010. When cumulative mean daily temperature increased by 10 °C, the season start was accelerated by 1 day. The input of the interaction between these two independent variables into the factor regression model caused the increase in goodness of model fitting. In 2011 the season started 5 days earlier in comparison with the predicted value, while in 2012 the season start was observed 2 days later compared to the predicted day. Depending on the value of mean daily temperature from March 18th to the 31st and the sum of mean daily temperature amplitudes from April 1st to the 14th, the grass pollen seasons were divided into five groups referring to the time of season start occurrence, whereby the early and moderate season starts were the most frequent in the studied period and they were especially related to mean daily temperature in the second half of March.

Exploring the spatio-temporal relationship between two key aeroallergens and meteorological variables in the United Kingdom

Constructing accurate predictive models for grass and birch pollen in the air, the two most important aeroallergens, for areas with variable climate conditions such as the United Kingdom, require better understanding of the relationships between pollen count in the air and meteorological variables. Variations in daily birch and grass pollen counts and their relationship with daily meteorological variables were investigated for nine pollen monitoring sites for the period 2000-2010 in the United Kingdom. An active pollen count sampling method was employed at each of the monitoring stations to sample pollen from the atmosphere. The mechanism of this method is based on the volumetric spore traps of Hirst design (Hirst in Ann Appl Biol 39(2):257-265, 1952). The pollen season (start date, finish date) for grass and birch were determined using a first derivative method. Meteorological variables such as daily rainfall; maximum, minimum and average temperatures; cumulative sum of Sunshine duration; wind speed; and relative humidity were related to the grass and birch pollen counts for the pre-peak, post peak and the entire pollen season. The meteorological variables were correlated with the pollen count data for the following temporal supports: same-day, 1-day prior, 1-day mean prior, 3-day mean prior, 7-day mean prior. The direction of influence (positive/negative) of meteorological variables on pollen count varied for birch and grass, and also varied when the pollen season was treated as a whole season, or was segmented into the pre-peak and post-peak seasons. Maximum temperature, sunshine duration and rainfall were the most important variables influencing the count of grass pollen in the atmosphere. Both maximum temperature (pre-peak) and sunshine produced a strong positive correlation, and rain produced a strong negative correlation with grass pollen count in the air. Similarly, average temperature, wind speed and rainfall were the most important variables influencing the count of birch pollen in the air. Both wind speed and rain produced a negative correlation with birch pollen count in the air and average temperature produced a positive correlation.

Personal exposure to grass pollen: relating inhaled dose to background concentration

BACKGROUND

Very few studies on human exposure to allergenic pollen have been conducted using direct methods, with background concentrations measured at city center monitoring stations typically taken as a proxy for exposure despite the inhomogeneous nature of atmospheric pollen concentrations. A 2003 World Health Organization report highlighted the need for an improved understanding of the relation between monitoring station data and actual exposure.

OBJECTIVE

To investigate the relation between grass pollen dose and background concentrations measured at a monitoring station, to assess the fidelity of monitoring station data as a qualitative proxy for dose, and to evaluate the ratio of dose rate to background concentration.

METHODS

Grass pollen dose data were collected in Aarhus, Denmark, in an area where grass pollen sources were prevalent, using Nasal Air Samplers. Sample collection lasted for approximately 25 to 30 minutes and was performed at 2-hour intervals from noon to midevening under moderate exercise by 2 individuals.

RESULTS

A median ratio of dose rate to background concentration of 0.018 was recorded, with higher ratio values frequently occurring at 12 to 2 PM, the time of day when grass species likely to be present in the area are expected to flower. From 4 to 8 PM, dose rate and background concentration data were found to be strongly and significantly correlated (rs = 0.81). Averaged dose rate and background concentration data showed opposing temporal trends.

CONCLUSION

Where local emissions are not a factor, background concentration data constitute a good quantitative proxy for inhaled dose. The present ratio of dose rate to background concentration may aid the study of dose-response relations.

Grass pollen allergy in children and adolescents-symptoms, health related quality of life and the value of pollen prognosis

INTRODUCTION

An association between pollen count (Poaceae) and symptoms is well known, but to a lesser degree the importance of priming and lag effects. Also, threshold levels for changes in symptom severity need to be validated. The present study aims to investigate the relationship between pollen counts, symptoms and health related quality of life (HRQL), and to validate thresholds levels, useful in public pollen warnings.

MATERIAL AND METHODS

Children aged 7-18 with grass pollen allergy filled out a symptom diary during the pollen season for nose, eyes and lung symptoms, as well as a HRQL questionnaire every week. Pollen counts were monitored using a volumetric spore trap.

RESULTS

89 (91%) of the included 98 children completed the study. There was a clear association between pollen count, symptom severity and HRQL during the whole pollen season, but no difference in this respect between early and late pollen season. There was a lag effect of 1-3 days after pollen exposure except for lung symptoms. We found only two threshold levels, at 30 and 80 pollen grains/m(3) for the total symptom score, not three as is used today. The nose and eyes reacted to low doses, but for the lung symptoms, symptom strength did hardly change until 50 pollen grains/m(3).

CONCLUSION

Grass pollen has an effect on symptoms and HRQL, lasting up to 5 days after exposure. Symptoms from the lungs appear to have higher threshold levels than the eyes and the nose. Overall symptom severity does not appear to change during the course of season. Threshold levels need to be revised. We suggest a traffic light model for public pollen warnings directed to children, where green signifies "no problem", yellow signifies "can be problems, especially if you are highly sensitive" and red signifies "alert - take action".

Hay fever in a changing climate: linking an Internet-based diary with environmental data

Investigating the impact of climate change on human health requires the development of efficient tools that link patient symptoms with changing environmental variables. We developed an internet-based hay fever diary linked to simultaneously recorded pollen load and weather variables in Canberra, Australia over spring 2010. We recruited 42 hay fever sufferers to complete a simple online pollen diary daily over a period of 60 days. In conjunction, daily airborne pollen load was counted and meteorological data collected simultaneously. We focused on the relationships between temperature, rainfall, pollen count and rhinoconjunctivitis symptoms. Pollen load increased after a peak rainfall event until the end of the study. Compliance was high, averaging 79% of days per person. Nasal rhinoconjunctivitis symptoms increased in concert with increasing pollen load, and then remained high. Mucosal itching increased more gradually and strongly coincided with increased daily maximum temperature. Our study successfully demonstrated the feasibility of linking pollen load and climate variables to symptoms of rhinoconjunctivitis in the Australian community. However, a larger study would better explore the nature of associations between these variables. Similar online methods could be used to monitor a range of health responses to our changing environment.

The role of seasonal grass pollen on childhood asthma emergency department presentations

BACKGROUND

Few studies have focused on the role of grass pollen on asthma emergency department (ED) presentations among children. None have examined whether a dose-response effect exists between grass pollen levels and these asthma exacerbations.

OBJECTIVES

To examine the association between increasing ambient levels of grass pollen and asthma ED presentations in children. To determine whether these associations are seen only after a thunderstorm, or whether grass pollen levels have a consistent influence on childhood asthma ED visits during the season.

METHODS

A short time series ecological study was conducted for asthma presentations to ED among children in Melbourne, Victoria, and grass pollen, meteorological and air quality measurements recorded during the selected 2003 period. A semi-parametric Poisson regression model was used to examine dose-response associations between daily grass pollen levels and mean daily ED attendance for asthma.

RESULTS

A smoothed plot suggested a dose-response association. As ambient grass pollen increased to about 19 grains/m(3) , the same day risk of childhood ED presentations also increased linearly (P < 0.001). Grass pollen levels were also associated with an increased risk in asthma ED presentations on the following day (lag 1, P < 0.001).

CONCLUSION

This is the first study to establish a clear relationship between increased risk of childhood asthma ED attendance and levels of ambient grass pollen below 20 grains/m(3) , independent of any impact of thunderstorm-associated asthma. These findings have important implications for patient care, such as asthma management programs that notify the general public regarding periods of high grass pollen exposure, as well as defining the timing of initiation of pollen immunotherapy.

Treatment of seasonal allergic rhinoconjunctivitis with a once-daily SQ-standardized grass allergy immunotherapy tablet

OBJECTIVES

Specific immunotherapy with the grass allergy immunotherapy tablet (AIT) has been developed as an effective, well tolerated, and convenient treatment for grass pollen induced seasonal allergic rhinoconjunctivitis (ARC). Six phase II/III randomized, placebo-controlled trials with the duration of a single grass pollen season of treatment using the SQ-standardized grass AIT, Grazax (Phleum pratense, 75,000 SQ-T/2,800 BAU, ALK, Denmark), have been published previously. This review compares results from these trials.

METHODS

As outcome measures and methods of assessing them were similar across the trials, we have summarized the main efficacy findings (Total Combined Score [TCS], average daily rhinoconjunctivitis symptom and medication scores, percentage of well days, quality of life scores) during a single season of treatment with grass AIT in adults and children with seasonal ARC.

RESULTS

The results of the European and North American trials were similar. Compared with the placebo group, who received symptomatic medications only, treatment with grass AIT resulted in fewer rhinoconjunctivitis symptoms, a lower intake of symptomatic medication, better patient self-rated quality of life and a greater percentage of well days during the entire grass pollen season. The data indicate that grass AIT treatment is equally effective in adults and children; the measured effect varies with pollen exposure, but is comparable across regions and continents, with a consistent difference compared with placebo in TCS that was above 20% for all trials. Local adverse events were experienced by the majority of patients. These reactions were generally mild to moderate in severity and transient in duration. Systemic adverse events were rare.

CONCLUSIONS

This review confirms SQ-standardized grass AIT as a suitable therapeutic option for seasonal use in patients aged 5 years or older with grass pollen induced ARC.

A nasally applied cellulose powder in seasonal allergic rhinitis (SAR) in children and adolescents; reduction of symptoms and relation to pollen load

BACKGROUND

A nasally applied cellulose powder is increasingly used in many countries as a remedy for allergic rhinitis. The absence of side effects makes the treatment particularly attractive in children. The efficacy in pollen allergic children, however, is not studied, nor is the relation to various pollen exposures.

METHODS

During the birch pollen season in 2009, a double blind, placebo-controlled study was conducted in 53 subjects, aged 8-18 yr, with allergic rhinitis attributed to birch pollen. All children were on daily oral antihistamine. Reminders and reporting of symptom scores were made by SMS on mobile phones. Pollen was collected in a volumetric trap from which figures of pollen concentrations from 1979 to 2009 were available.

RESULTS

There was a significant reduction in total symptom scores from the nose (Placebo 7.29, Active 6.07, p = 0.033) and specifically for running nose (Placebo 2.56, Active 2.03, p = 0.017). All symptoms from the nose, eyes and lower airways were lower in the active group but reached significance only as earlier. The best effect was seen after days with low or moderate pollen counts (≤100/m(3)), the predominating pollen load over 31 yr in the area. No clinically significant adverse effects were seen.

CONCLUSIONS

The product reduces symptoms of SAR in children and adolescents. Original data on pollen concentrations over 31 yr are presented with levels mainly in the low range favouring the observed efficacy profile. SMS communication on mobile phone for reminders and recording symptom scores was an excellent logistics tool.

Threat of allergenic airborne grass pollen in Szczecin, NW Poland: the dynamics of pollen seasons, effect of meteorological variables and air pollution

The dynamics of Poaceae pollen season, in particularly that of the Secale genus, in Szczecin (western Poland) 2004-2008 was analysed to establish a relationship between the meteorological variables, air pollution and the pollen count of the taxa studied. Consecutive phases during the pollen season were defined for each taxon (1, 2.5, 5, 25, 50, 75, 95, 97.5, 99% of annual total), and duration of the season was determined using the 98% method. On the basis of this analysis, the temporary differences in the dynamics of the seasons were most evident for Secale in 2005 and 2006 with the longest main pollen season (90% total pollen). The pollen season of Poaceae started the earliest in 2007, when thermal conditions were the most favourable. Correlation analysis with meteorological factors demonstrated that the relative humidity, mean and maximum air temperature, and rainfall were the factors influencing the average daily pollen concentrations in the atmosphere; also, the presence of air pollutants such as ozone, PM(10) and SO(2) was statistically related to the pollen count in the air. However, multiple regression models explained little part of the total variance. Atmospheric pollution induces aggravation of symptoms of grass pollen allergy.

On the causes of variability in amounts of airborne grass pollen in Melbourne, Australia

In Melbourne, Australia, airborne grass pollen is the predominant cause of hay fever (seasonal rhinitis) during late spring and early summer, with levels of airborne grass pollen also influencing hospital admissions for asthma. In order to improve predictions of conditions that are potentially hazardous to susceptible individuals, we have sought to better understand the causes of diurnal, intra-seasonal and inter-seasonal variability of atmospheric grass pollen concentrations (APC) by analysing grass pollen count data for Melbourne for 16 grass pollen seasons from 1991 to 2008 (except 1994 and 1995). Some of notable features identified in this analysis were that on days when either extreme (>100 pollen grains m(-3)) or high (50-100 pollen grains m(-3)) levels of grass pollen were recorded the winds were of continental origin. In contrast, on days with a low (<20 pollen grains m(-3)) concentration of grass pollen, winds were of maritime origin. On extreme and high grass pollen days, a peak in APC occurred on average around 1730 hours, probably due to a reduction in surface boundary layer turbulence. The sum of daily APC for each grass pollen season was highly correlated (r = 0.79) with spring rainfall in Melbourne for that year, with about 60% of a declining linear trend across the study period being attributable to a reduction of meat cattle and sheep (and hence grazing land) in rural areas around Melbourne. Finally, all of the ten extreme pollen events (3 days or more with APC > 100 pollen grains m(-3)) during the study period were characterised by an average downward vertical wind anomaly in the surface boundary layer over Melbourne. Together these findings form a basis for a fine resolution atmospheric general circulation model for grass pollen in Melbourne's air that can be used to predict daily (and hourly) APC. This information will be useful to those sectors of Melbourne's population that suffer from allergic problems.

Determination of ranges for reporting pollen aeroallergen levels in the Washington, DC, metropolitan area

BACKGROUND

Local aeroallergen monitoring provides useful information for the atopic patient and medical community. Currently, National Allergy Bureau (NAB) ranges are used for reporting pollen count levels in the Washington, DC, area.

OBJECTIVE

To determine standard range criteria (low, moderate, high, and very high) for the reporting of specific tree, grass, and weed aeroallergens representative of the Washington, DC, metropolitan region.

METHODS

Atmospheric sampling for pollen aeroallergens was performed using a volumetric rotating-arm impaction sampler (model 40 Rotorod, SDI Company, Plymouth Meeting, PA). The cumulative pollen count, over a 12-year period (1998-2009), was determined for specific pollen aeroallergens. Local ranges were developed using methodology previously employed to determine NAB ranges. A comparison was made between NAB and Washington, DC, area ranges.

RESULTS

The local median count, and low and moderate range criteria, are markedly lower than NAB range counts for tree, grass, and weed pollen. The NAB 99th percentile (high) count is significantly higher for grass and weed pollen but lower for tree pollen. Using new local range criteria, an increase was seen in the number of high days recorded for weed pollen (1,300%), grass pollen (258.6%), and tree pollen (11.8%). Previously, using NAB range criteria, no very high days were reported for grass and weed pollen over the 12-year period.

CONCLUSION

Washington, DC, ranges establish more relevant reporting standards for our local patient population and will allow for comparison with reporting levels developed for sampling locations nationwide as well as with other regional sites.

Poaceae pollen in Galicia (N.W. Spain): characterisation and recent trends in atmospheric pollen season

Airborne Poaceae pollen counts are greatly influenced by weather-related parameters, but may also be governed by other factors. Poaceae pollen is responsible for most allergic reactions in the pollen-sensitive population of Galicia (Spain), and it is therefore essential to determine the risk posed by airborne pollen counts. The global climate change recorded over recent years may prompt changes in the atmospheric pollen season (APS). This survey used airborne Poaceae pollen data recorded for four Galician cities since 1993, in order to characterise the APS and note any trends in its onset, length and severity. Pollen sampling was performed using Hirst-type volumetric traps; data were subjected to Spearman's correlation test and regression models, in order to detect possible correlations between different parameters and trends. The APS was calculated using ten different methods, in order to assess the influence of each on survey results. Finally, trends detected for the major weather-related parameters influencing pollen counts over the study period were compared with those recorded over the last 30 years. All four cities displayed a trend towards lower annual total Poaceae pollen counts, lower peak values and a smaller number of days on which counts exceeded 30, 50 and 100 pollen grains/m(3). Moreover, the survey noted a trend towards delayed onset and shorter duration of the APS, although differences were observed depending on the criteria used to define the first and the last day of the APS.

Evaluation of atmospheric Poaceae pollen concentration using a neural network applied to a coastal Atlantic climate region

In the South of Europe an important percentage of population suffers pollen allergies, being the Poaceae pollen the major source. One of aerobiology's objectives is to develop statistical models enabling the short- and long-term prediction of atmospheric pollen concentrations to take preventative measures to protect allergic patients from the severity of the atmospheric pollen season. The implementation of a computational model based on supervised MLP neural network was applied for the prediction of the atmospheric Poaceae pollen concentration. There is a good correlation between the values predicted by the ANN for the training cases in comparison with the real pollen concentrations. A high coefficient of linear regression (R(2)) of 0.9696 was obtained. The accuracy of the neural network developed was tested with data from 2006 and 2007, which was not taken into account to establish the aforementioned models. Neural networks provided us a good tool to forecasting allergenic airborne pollen concentration helping the automation of the prediction system in the aerobiological information diffusion to the population suffering from allergic problems.

Time and intensity of first pollen contacts and risk of subsequent pollen allergies

We find that the risks of immediate hypersensitivity to grass and mugwort pollens, as measured by a skin test, are positively correlated with the intensity of the first pollen season encountered in infancy. However, only indirect measures of the intensity of the pollen seasons (weather factors and vegetative growth of grasses) were available for the regression analysis performed. The risks were also dependent on the month of birth, maximal risk for both grass and mugwort pollen sensitivity being associated with birth in April-May. The results support an earlier suggestion that pollen contacts during the first 6 months of life increase the risk of pollen allergy for 20 years or more. We estimate that the elimination of early pollen contacts could have reduced the prevalence of immediate hypersensitivity to grass and mugwort pollens by approximately 20% each in the age group 0-19 years.

Serum allergen specific immunoglobulin E levels in patients with allergic conjunctivitis

PURPOSE

To evaluate serum allergen specific immunoglobulin E (IgE) levels in patients with various types of allergic conjunctivitis.

METHODS

Twenty-five patients with seasonal allergic conjunctivitis (SAC), 17 patients with perennial allergic conjunctivitis (PAC), and 10 patients with vernal conjunctivitis (VC) were included in the study. Specific IgE levels to Dermatophagoides pteronyssinus (Dp), Dermatophagoides farinae (Df), mixed grass pollens, and animal epithelia were measured using Pharmacia CAP system (Pharmacia Diagnostic AB, Uppsala, Sweden).

RESULTS

The percentage of subjects with specific IgE against Dp and Df was statistically higher in VC (30%) compared to PAC (5.9%) and SAC (0%) (p=0.03). Specific IgE against mixed grass pollens was found in 30% of VC and 40% of SAC, whereas 10% of VC and 8% of SAC patients were found to be hypersensitive to animal epithelia.

CONCLUSIONS

Allergic reaction against house dust mites and pollens was common in VC, whereas specific IgE against grass pollens was remarkable in SAC. IgE levels specific to various antigens might be measured by UNICAP system, which is a rapid and practical technology.

Do levels of airborne grass pollen influence asthma hospital admissions?

BACKGROUND

The effects of environmental factors and ambient concentrations of grass pollen on allergic asthma are yet to be established.

OBJECTIVE

We sought to estimate the independent effects of grass pollen concentrations in the air over Melbourne on asthma hospital admissions for the 1992-1993 pollen season.

METHODS

Daily grass pollen concentrations were monitored over a 24-h period at three stations in Melbourne. The outcome variable was defined as all-age asthma hospital admissions with ICD9-493 codes. The ambient air pollutants were average daily measures of ozone, nitrogen dioxide and sulphur dioxide, and the airborne particle index representing fine particulate pollution. Semi-parametric Poisson regression models were used to estimate these effects, adjusted for air temperature, humidity, wind speed, rainfall, day-of-the-week effects and seasonal variation.

RESULTS

Grass pollen was a strong independent non-linear predictor of asthma hospital admissions in a multi-pollutant model (P=0.01). Our data suggest that grass pollen had an increasing effect on asthma hospital admissions up to a threshold of 30 grains/m3, and that the effect remains stable thereafter.

CONCLUSION

Our findings suggest that grass pollen levels influence asthma hospital admissions. High grass pollen days, currently defined as more than 50 grains/m3, are days when most sensitive individuals will experience allergic symptoms. However, some asthmatic patients may be at a significant risk even when airborne grass pollen levels are below this level. Patients with pollen allergies and asthma would be advised to take additional preventive medication at lower ambient concentrations.

Allergenic pollen and pollen allergy in Europe

The allergenic content of the atmosphere varies according to climate, geography and vegetation. Data on the presence and prevalence of allergenic airborne pollens, obtained from both aerobiological studies and allergological investigations, make it possible to design pollen calendars with the approximate flowering period of the plants in the sampling area. In this way, even though pollen production and dispersal from year to year depend on the patterns of preseason weather and on the conditions prevailing at the time of anthesis, it is usually possible to forecast the chances of encountering high atmospheric allergenic pollen concentrations in different areas. Aerobiological and allergological studies show that the pollen map of Europe is changing also as a result of cultural factors (for example, importation of plants such as birch and cypress for urban parklands), greater international travel (e.g. colonization by ragweed in France, northern Italy, Austria, Hungary etc.) and climate change. In this regard, the higher frequency of weather extremes, like thunderstorms, and increasing episodes of long range transport of allergenic pollen represent new challenges for researchers. Furthermore, in the last few years, experimental data on pollen and subpollen-particles structure, the pathogenetic role of pollen and the interaction between pollen and air pollutants, gave new insights into the mechanisms of respiratory allergic diseases.

Epidemic asthma and the role of the fungal mold Alternaria alternata

BACKGROUND

After July 29, 2002, an epidemic of asthma admissions was associated with a thunderstorm in the United Kingdom.

OBJECTIVE

We sought to study the cause of epidemics of asthma associated with thunderstorms.

METHODS

We performed a case-control study of 26 patients presenting to Cambridge University Hospital with asthma after the thunderstorm. Control subjects were 31 patients with summer seasonal asthma. Subjects underwent skin tests and specific IgE serology to inhaled aeroallergens. Meteorologic and aerobiologic data correlated with asthma admissions were analyzed.

RESULTS

Twenty-three of 26 cases had IgE sensitization to Alternaria species. Eleven of 31 control subjects gave a history of asthma exacerbation during thunderstorms. Ten of these 11 control subjects were sensitive to Alternaria species on skin testing, but Alternaria species sensitivity was only identified in 4 of the 20 remaining control subjects who did not report thunderstorm-related asthma symptoms. The odds ratio of having epidemic thunderstorm-related asthma if sensitive to Alternaria species was 9.31 (95% CI, 2.305-37.601; P = .0008) and 63.966 (95% CI, 3.577-1143.9; P < .0001) if sensitive to Alternaria species, Cladosporium species, or both. Poisson regression analysis showed that counts of broken Alternaria species and Didymella and Cladosporium species were significantly correlated with each other and with asthma admissions. The thunderstorm was associated with increased levels of Alternaria, Cladosporium, and Didymella species.

CONCLUSIONS

Alternaria alternata sensitivity is a compelling predictor of epidemic asthma in patients with seasonal asthma and grass pollen allergy and is likely to be the important factor in thunderstorm-related asthma.

CLINICAL IMPLICATIONS

Alternaria species sensitization in asthmatic subjects with grass pollen sensitivity predicts susceptibility to thunderstorm-associated asthma.

Constructing a 7-day ahead forecast model for grass pollen at north London, United Kingdom

BACKGROUND

A number of media outlets now issue medium-range ( approximately 7 day) weather forecasts on a regular basis. It is therefore logical that aerobiologists should attempt to produce medium-range forecasts for allergenic pollen that cover the same time period as the weather forecasts.

OBJECTIVE

The objective of this study is to construct a medium-range (</=7 day) forecast model for grass pollen at north London.

METHOD

The forecast models were produced using regression analysis based on grass pollen and meteorological data from 1990 to 1999 and tested on data from 2000 and 2002. The modelling process was improved by dividing the grass pollen season into three periods; the pre-peak, peak and post-peak periods of grass pollen release. The forecast consisted of five regression models: two simple linear regression models predicting the start and end date of the peak period, and three multiple regression models forecasting daily average grass pollen counts in the pre-peak, peak and post-peak periods.

RESULTS

Overall, the forecast models achieved 62% accuracy in 2000 and 47% in 2002, reflecting the fact that the 2002 grass pollen season was of a higher magnitude than any of the other seasons included in the analysis.

CONCLUSION

This study has the potential to make a notable contribution to the field of aerobiology. Winter averages of the North Atlantic Oscillation were used to predict certain characteristics of the grass pollen season, which presents an important advance in aerobiological work. The ability to predict allergenic pollen counts for a period between five and seven days will benefit allergy sufferers. Furthermore, medium-range forecasts for allergenic pollen will be of assistance to the medical profession, including allergists planning treatment and physicians scheduling clinical trials.

A double blind, placebo controlled trial of inert cellulose powder for the relief of symptoms of hay fever in adults

OBJECTIVE

An inert cellulose powder has been on sale in the UK since 1994 as a remedy for hay fever but no scientific trials have been conducted previously. It is applied to the inside of the nose where it forms a gelatinous coating. The principal aim was to determine if there is a significant difference in the amount and type of rescue medication required for adult hay fever sufferers to control their symptoms while using either the inert cellulose powder or a placebo. The second objective was to see whether the cellulose powder resulted in an improvement in symptom control.

RESEARCH DESIGN

A double blind, placebo controlled study was conducted of 97 adult hay fever sufferers, over the grass pollen season of 2004. Participants (selectively recruited to be living within the catchment area of a 50-km radius from Worcester, UK) were assigned randomly to two groups (A, Active and B, Placebo) matched by age by decades and gender. Of those completing the trial, group A had 19 males and 28 females and group B had 21 males and 29 females. There were no significant differences between the groups in age distributions, severity of symptoms over the last 2 years or in medication taken. They completed daily symptom diary score cards and were allowed to take any medications they wished in addition to the inert cellulose powder or placebo because medication use was taken as an outcome measure. Results were analysed in relation to pollen counts.

RESULTS

Significant differences were found in the amounts of rescue medication taken by the active and placebo groups (p < 0.05). More people in the placebo group took rescue treatments than those in the active group. No significant differences were found (p < 0.01) between the active and placebo groups in Likert scores for any of the rhinitis nasal symptoms or in the total Likert symptom daily scores. No adverse events were reported during the study.

CONCLUSIONS

The amount of rescue medication taken by the placebo group was significantly more than that taken by the active group both overall, considering all types of medication, and also in the individual cases of antihistamines, nasal sprays and eye drops. These results provide evidence that the inert cellulose powder reduces the need to take rescue medication for the symptoms of hay fever.

Ole e 2 and Ole e 10: new clinical aspects and genetic restrictions in olive pollen allergy

BACKGROUND

The clinical characteristics in olive pollen allergy are dependent on the antigenic load, the allergens profile, and the genetic restrictions. Our objective was to determine specific response pattern in Ole e 2 and Ole e 10 sensitization at those levels.

METHODS

We studied 146 patients with seasonal rhinitis and/or asthma and positive prick test to Olea europaea pollen. IgE against Ole e 2 and Ole e 10 were detected by skin prick test and ELISA. HLA-DRB1 and HLA-DQB1 loci were typed by polymerase chain reaction sequence-specific primers method.

RESULTS

A total of 102 (69.9%) and 79 (54.0%) patients showed significant IgE antibody response against Ole e 2 and Ole e 10, respectively. There was a significant association between Ole e 2 (OR 2.2, P = 0.04) and Ole e 10 reactivities (OR 2.8, P = 0.007) with asthma. In addition, total and specific IgE antibody levels significantly correlated with asthma (P < 0.05). Patients who reacted to both allergens reached the highest asthma risk factor (OR 4.3, P = 0.002). Phenotypic frequency of DR7 (OR 5.4, Pc = 0.003) and DQ2 (OR 3.6, Pc = 0.02) were increased in positive Ole e 2 patients compared with control subjects. DR2(15) phenotypic frequency was significantly increased (OR 5.6, Pc = 0.02) in positive Ole e 10 patients compared with control subjects.

CONCLUSIONS

Our data suggest an association of Ole e 2 and Ole e 10 with bronchial asthma. Also, we found a genetic control of Ole e 2 and Ole e 10 IgE-specific responses that could be relevant to clinical disease in olive pollen allergy.

Spatial variability in the pollen count in Sydney, Australia: can one sampling site accurately reflect the pollen count for a region?

BACKGROUND

There is increasing interest in the daily pollen count, with pollen-sensitive individuals using it to determine medication use and researchers relying on it for commencing clinical drug trials and assessing drug efficacy according to allergen exposure. Counts are often expressed qualitatively as low, medium, and high, and often only 1 pollen trap is used for an entire region.

OBJECTIVES

To examine the spatial variability in the pollen count in Sydney, Australia, and to compare discrepancies among low-, medium-, and high-count days at 3 sites separated by a maximum of 30 km.

METHODS

Three sites in western Sydney were sampled using Burkard traps. Data from the 3 sites were used to compare vegetation differences, possible effects of some meteorological parameters, and discrepancies among sites in low-, medium-, and high-count days.

RESULTS

Total pollen counts during the spring months were 14,382 grains/m3 at Homebush, 11,584 grains/m3 at Eastern Creek, and 9,269 grains/m3 at Nepean. The only significant correlation between differences in meteorological parameters and differences in pollen counts was the Homebush-Nepean differences in rainfall and pollen counts. Comparison between low- and high-count days among the 3 sites revealed a discordance rate of 8% to 17%.

CONCLUSIONS

For informing the public about pollen counts, the count from 1 trap is a reasonable estimation in a 30-km region; however, the discrepancies among 3 trap sites would have a significant impact on the performance of a clinical trial where enrollment was determined by a low or high count. Therefore, for clinical studies, data collection must be local and applicable to the study population.

Pollen counts in relation to the prevalence of allergic rhinoconjunctivitis, asthma and atopic eczema in the International Study of Asthma and Allergies in Childhood (ISAAC)

BACKGROUND

Although pollens are major allergens associated with allergic rhinoconjunctivitis and asthma, there is little information about the relative prevalence of these conditions in populations with different pollen exposures.

OBJECTIVE

The purpose of this study was to investigate the relationship between pollen exposure and allergic symptoms among children in different countries.

METHODS

An ecological analysis was conducted to see whether pollen exposure (pollen counts, and duration and severity of pollen seasons) is associated with symptoms of allergic rhinoconjunctivitis, asthma and atopic eczema in 28 centres within 11 countries (nine being in Europe). Data on the prevalence of symptoms in 13-14-year olds were based on the responses to the written questionnaires from the International Study of Asthma and Allergies in Childhood (ISAAC). The analysis was adjusted for gross national product and mean annual relative humidity.

RESULTS

There was little relationship between pollen exposure and symptom prevalence, except for a significant inverse association between grass pollen counts and lifetime prevalence of the symptoms of allergic rhinitis (P=0.03). Almost all the regression coefficients were negative. The associations were even weaker and all non-significant when the analyses were conducted within countries, using a random intercept fixed slope model, but there was still no evidence of a positive association between pollen exposure and symptoms.

CONCLUSION

There is a weak but consistent tendency for the prevalence of allergic symptoms to be inversely associated with pollen exposure. This finding accords with evidence from several countries, suggesting that the prevalence of hayfever and asthma tends to be lower in rural than in urban areas, and lowest among people living on farms. Exposure to allergenic pollen in early life does not appear to increase the risk of acquiring symptoms of respiratory allergy, and may even give some protection against them.

The use of a neural network to forecast daily grass pollen concentration in a Mediterranean region: the southern part of the Iberian Peninsula

BACKGROUND

Pollen allergy is a common disease causing hayfever in 15% of the population in Europe. Medical studies report that a prior knowledge of pollen content in the air can be useful in the management of pollen-related diseases.

OBJECTIVES

The aim of this work was to forecast daily Poaceae pollen concentrations in the air by using meteorological data and pollen counts from previous days as independent variables.

METHODS

Linear regression models and co-evolutive neural network models were used for this study. Pollen was monitored by a Hirst-type spore trap using standard techniques. The data were obtained from the Spanish Aerobiology Network database, University of Cordoba Monitoring Unit. The set of data includes a series of 20 years, from 1982 to 2001. A classification of the years according to their allergenic potential was made using a K-mean cluster analysis with pollen and meteorological parameters. Statistical analysis was applied to all the years of each class with the exception of the most recent year, which was used for model validation.

RESULTS

It was observed that cumulative variables and pollen values from previous days are the most important factors in the models. In general, neural network equations produce better results than linear regression equations.

CONCLUSION

Co-evolutive neural network models, which obtain the best forecasts (an almost 90% "good" classification), make it possible to predict daily airborne Poaceae pollen concentrations. This new system based on neural network models is a step toward the automation of the pollen forecast process.

Predictors of group 5 grass-pollen allergens in settled house dust: comparison between pollination and nonpollination seasons

BACKGROUND

Some sensitive pollen-allergic patients may experience perennial symptoms, and for these patients it is vitally important to know the concentration of grass-pollen allergens in their homes. The main objective of this study was to detect predictors associated with high grass allergen concentration in settled house dust during and outside the grass pollination season.

METHODS

We detected group 5 grass-pollen allergens in dust samples from randomly selected homes of three counties in the region of Sachsen-Anhalt: Hettstedt (n=183), Zerbst (n=152), and Bitterfeld (n=119). Dust samples were collected from the floors of living rooms (LR) and children's rooms (CR) from April 1996 to March 1998.

RESULTS

Phl p 5 was detected in settled house dust in 91% of the homes. The range was between undetectable (<30 ng/m2) and 4300 ng Phl p 5/m2 sampling area during grass pollination, and 1300 ng Phl p 5/m2 outside the pollination season, respectively. We observed a partially higher concentration of indoor allergenic activity several weeks after the grass-pollen peak. A positive association was found between Phl p 5 levels and total dust amounts throughout the year. Thus, we assume that grass allergens accumulate in settled house dust. During pollination, the Phl p 5 levels are 1.8 times higher in homes where vacuuming of carpets takes place only once a week or less than in those vacuumed daily. Furthermore, higher concentrations of Phl p 5 in settled floor dust can be expected in homes located within suburban areas (mean ratio [MR] 1.74) and prefabricated slab buildings (MR=1.54).

CONCLUSIONS

Quite high levels of Phl p 5 accumulate in settled house dust even during periods when no grass pollen is present in the atmosphere. The removal of dust by frequent cleaning reduces the indoor exposure to grass allergens. Such information is essential to train patients in allergen avoidance.

A springtime olympics demands special consideration for allergic athletes

BACKGROUND

The Sydney Olympic and Paralympic Games will be held in September-October 2000, which is early to mid-spring in the southern hemisphere. Pollen-sensitive athletes may encounter problems with allergic symptoms triggered by pollen exposure, thus compromising their ability to attain peak performance.

OBJECTIVE

We sought to monitor pollen levels at the major Olympic venues to provide information for allergic athletes and their team doctors in order to adequately prepare them for Olympic competition.

METHODS

We performed aerobiologic monitoring of the major Olympic venues to provide a profile of the most prevalent pollen species appearing during the spring. In the second part of this study, we surveyed a population of elite Australian athletes from Olympic sports to ascertain the prevalence of allergic rhinoconjunctivitis, to investigate the major allergens involved in sensitization, and to conduct a pilot study to assess the effect of allergic rhinoconjunctivitis on quality of life.

RESULTS

The pollen counts obtained at the 3 major sites were high over the period of Olympic competition. Tree pollens appeared from July, and grasses appeared from early September and peaked in the second week of October, the beginning of Paralympic competition. A relatively small number of pollen varieties comprise the majority of the total pollen count. Two hundred fourteen athletes (61% male; mean age, 21 +/- 16 years) representing 12 Olympic sports participated in the study. Fifty-six percent gave a symptom history consistent with allergic rhinoconjunctivitis, 41% had symptoms of allergic rhinoconjunctivitis and a positive test response to any one allergen, and 29% had seasonal allergic rhinoconjunctivitis (a positive history and at least one positive skin prick test response to a seasonal allergen). Athletes from aquatic sports were more likely to have symptoms than those from other sports. Symptom scores were higher and quality of life ratings were poorer in allergic compared with nonallergic athletes over the spring period.

CONCLUSION

Olympic team managers and medical officers need to adequately prepare Olympic athletes for the possibility of exposure to high pollen levels in the weeks leading up to this most important sporting event. Symptoms of pollen sensitivity, such as rhinoconjunctivitis and exacerbation of asthma, could be devastating to athletes expecting peak performance. Potential Olympic athletes should be screened for the possibility of pollen allergy and have medical programs with permitted medication tailored to meet their needs. This may involve preventative therapy with medication, such as intranasal corticosteroid sprays or immunotherapy programs, if symptoms are particularly severe. The newer nonsedating antihistamines are the treatment of choice for acute intermittent symptoms. Appropriate management will ensure that the allergic athlete will safely perform to maximum ability with permitted medication during the Spring 2000 Olympic Games in Sydney.