Respiratory hospital admissions were associated with ambient airborne pollen in Darwin, Australia, 2004–2005

BACKGROUND: Although the role of pollen and fungus in specific allergic disorders has been well established, the public health impacts of ambient concentrations of airborne pollen and fungal spores; the shapes of concentration-response relationships; and the relative effects of different taxa are gaps in current knowledge. OBJECTIVE: To investigate associations between daily average ambient pollen and fungal spore concentrations with hospital admissions for total respiratory diseases; asthma; chronic obstructive pulmonary disease (COPD); and respiratory infections in Darwin, Australia, during the period from April 2004 to November 2005. METHODS: We assessed these relationships in a two-stage modelling approach designed to quantify potential non-linear relationships. First, generalized additive models determined the shapes of concentration-response relationships. Second, linear associations were examined using generalized linear models. Non-linear relationships were analysed by categorizing pollen and fungal spore concentrations based on their distributions. RESULTS: Positive linear associations were found between total pollen concentrations and hospital admissions for total respiratory diseases and COPD. While our exploratory first-stage analysis suggested non-linear relationships for total pollen with asthma and respiratory infections, no convincing evidence for these relationships was found in the second-stage analysis. When individual taxa were investigated, associations were the strongest in relation to Myrtaceae pollen (the dominant tree taxa in the region), while positive associations not attaining statistical significance were observed for Poaceae, Cyperaceae and Arecaceae. No associations were evident for any conditions with fungal spores. CONCLUSIONS: Our finding of an association between pollen count and respiratory hospital admissions that could not be explained by asthma admissions suggests that ambient airborne pollens might have a wider public health impact than previously recognized.     

Allergenic pollens and pollinosis in Italy: recent advances

The authors have mapped the occurrence of allergenic pollens throughout Italy and defined their most common clinical symptoms. To obtain an accurate aerobiological and clinical picture of such a geographically complex country as Italy, a detailed investigation was carried out involving 80 data-gathering stations and 40 clinical centers nationwide. Three main pollination periods can be distinguished: winter-pre-spring (January to March) for Betulaceae, Corylaceae, Cupressaceae, Salicaceae and Ulmaceae: spring-summer (April to June) for Gramineae, Urticaceae, Oleaceae, Plantago, Fagaceae, Pinaceae and Polygonaceae , and summer-autumn (August to September) for Urticaceae, Composilae and Chenopodiaceae. Examination of 49660 patients affected by pollinosis (conjunctivitis, rhinitis, asthma, with positive skin tests or IgE-specific serum determination: RAST, ELISA) throughout Italy revealed sensitivity to Gramineae in 64.6%, to Parietaria in 36.7% to Oka in 15.8%, to Compositae in 13.2%, to Betulaceae-Corylaceae in 7% and to Fagaceae-Cupressaceae-Plantago in 4%–10%; marked regional variations were observed. The patients suffered from rhino-conjunctivitis (55.7%), rhino-conjunctivitis plus asthma (31.6%) and asthma (12.7%). In monosensitised individuals, Parietaria was seen to be the main cause of the asthmatic syndrome (though our preliminary data also implicate Olea followed by Grawmeae.     

The potential role of orbicules as a vector of allergens

BACKGROUND: In the locules of anthers of flowering plants, tiny (1.5-2 microm) granules of sporopollenin may occur next to the pollen grains. Those granules, called orbicules, mostly occur on the radial and innermost tangential wall of secretory tapetum cells. METHODS: We have investigated the presence of orbicules in 15 important European allergenic species with scanning electron microscopy (SEM). RESULTS: Orbicules were present in all species investigated of the families Betulaceae, Chenopodiaceae, Fagaceae, Poaceae, Polygonaceae, and Urticaceae. However, in the Asteraceae and Oleaceae species studied, orbicules were lacking. In all Chenopodiaceae, Poaceae, and Urticaceae species, orbicules were attached to the pollen exine. These observations indicate the possibility of the dispersal of orbicules into the atmosphere during anthesis. CONCLUSIONS: The hypothesis of the potential role of orbicules as possible important vectors of allergens is put forward, based on the comparison of our results with recent literature about the evidence of allergenic activity in the smaller micronic atmospheric aerosol fraction. Our results provide evidence that an in-depth investigation of the sites of allergens across the whole anther is required. We suggest that allergen researchers apply immunoelectron microscopy on whole anthers to determine whether orbicules possess allergens.     

Rhinitis therapy and the prevention of hospital care for asthma: a case-control study

BACKGROUND: Although clinical trials have demonstrated that rhinitis therapy improves subjective and objective measures of asthma, it is uncertain whether treatment of allergic rhinitis significantly affects the frequency of asthma exacerbations. OBJECTIVE: The objective of this study was to determine whether treatment with intranasal corticosteroids and/or second-generation antihistamines is associated with changes in rates of asthma exacerbations resulting in emergency room visits and/or hospitalizations in patients with asthma and allergic rhinitis. METHODS: This was a nested, case-control study. RESULTS: Treatment with either nasal corticosteroids or second-generation antihistamines was associated with a lower risk of asthma-related emergency room treatment and hospitalization (adjusted odds ratio [OR], 0.51; 95% CI, 0.34 to 0.77 and 0.34, 0.18 to 0.62, respectively). Patients who used nasal corticosteroids had a significantly lower risk of both asthma-related emergency room treatment and hospitalization (adjusted OR, 0.75; 95% CI, 0.62 to 0.91 and 0.56, 0.42 to 0.76, respectively), whereas there was a trend toward lower risk of emergency room treatment and hospitalization in patients who used second-generation antihistamines (adjusted OR, 0.88; 95% CI, 0.62 to 1.26 and 0.68, 0.40 to 1.14, respectively). Combined treatment with both medications was associated with a further lowering of the risk of both emergency room treatment and hospitalization (adjusted OR, 0.37; 95% CI, 0.19 to 0.73 and 0.22, 0.07 to 0.63). CONCLUSIONS: In patients with asthma, treatment of concomitant allergic rhinitis was associated with significant reductions in risk of emergency room treatment and hospitalization for asthma.     

Seasonal Patterns of Asthma in Children and Adolescents Presenting at Emergency Departments in Korea

PurposeSeasonal variations in asthma-related hospitalizations and emergency department visits have long been recognized. This study aimed to investigate the seasonal patterns of asthma in children and adolescents who presented at emergency departments in Korea.MethodsWe analyzed the National Emergency Department Information System records from 117 emergency departments in Korea that comprised all of the patients with asthma who were aged 3-18 years and who presented at the emergency departments from 2007 to 2012. The children and adolescents were divided into 3 groups based on their ages, namely, 3-6 years, 7-12 years, and 13-18 years. The data were tabulated, and graphs were created to show the seasonal trends in the monthly numbers of emergency department visits as a consequence of asthma.ResultsA total of 41,128 subjects were identified, and the male-to-female ratio was 1:0.5. General ward admissions comprised 42.6% (n=17,524 patients) of the emergency department visits, and intensive care unit admissions comprised 0.8% (n=335 patients) of the emergency department visits. The monthly numbers of emergency department visits for asthma varied according to the season, with high peaks during fall, which was from September to November, and low levels in summer, which was from June to August.ConclusionsImportant differences in the seasonal patterns of emergency department visits for asthma were evident in children and adolescents. Identifying seasonal trends in asthma-related emergency department visits may help determine the causes and reduce the likelihood of asthma exacerbation.     

Allergenic pollens in the southern Mediterranean area

In the Mediterranean area there are characteristic climatic conditions (mildness of winter, summer dryness, etc.) that facilitate the growing of a typical vegetation with production of allergenic pollen, such as those from Parietaria and Olea europaea, very different from that of central and northern Europe. We present in this article the results of an 8-year pollen count in the atmosphere of Naples, Italy. The pollen content was examined with a volumetric spore trap (Lanzoni VPPS-2000) like that of Hirst. The results of the pollen counts were subsequently compared with results of skin tests of patients born and still living in and around Naples to determine the pollinosis of that area. We found that the most important allergenic pollen in the Naples area is Parietaria, with very long-lasting periods of pollination. The first period, more important, occurring from March to July, and the second period of much lower intensity, occurring from the end of August to the end of October. Pollen allergy to Parietaria was found to be present in 82.02% of pollen-allergic patients. It was followed by Gramineae (32.12%), Olea (23.11%), and Artemisia vulgaris (17.08%). These data are quite different from data of the pollinosis in northern Italy and in the northern Mediterranean area, as well as the southern coast of France, where allergic sensitization to Poaceae is the most important.     

Association of control and risk of severe asthma-related events in severe or difficult-to-treat asthma patients

BACKGROUND: Clinical tools for predicting poor outcomes in asthma patients are lacking. This study investigated the association of asthma control and subsequent severe asthma-related healthcare events in The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study. METHODS: The extent of asthma control problems was determined from baseline values of the Asthma Therapy Assessment Questionnaire (ATAQ). Patients self-reported the presence of severe asthma-related events at 6- and 12-month follow up. Poisson regression models determined the adjusted association between baseline control and the likelihood of severe asthma-related events. RESULTS: At baseline, 2942 patients (mean age, 49.6 years; female, 71.9%) had an ATAQ score (no control problems, 17.0%; 1 control problem, 20.0%; 2 control problems, 30.8%; 3 or 4 control problems, 32.2%) and at least one severe asthma-related event. After adjustment, subjects with three or four control problems were at greater risk for unscheduled office visits [relative risk (RR) = 2.8; 95% confidence interval (CI): 2.4-3.2], course of oral steroids (RR = 2.9; 95% CI: 2.5-3.3), emergency room visits (RR = 4.1; 95% CI: 2.7-6.2) or hospitalization (RR = 13.6; 95% CI: 7.4-24.9), vs no control problems. Progressively poorer levels of asthma control are associated with increasing risk of severe asthma-related events. CONCLUSIONS: This study provides evidence of an association between poor asthma control and future severe asthma-related healthcare events. A validated questionnaire may help clinicians identify patients requiring intervention to prevent future severe asthma-related events.     

Correlation between Olea europaea and Parietaria judaica pollen counts and quantification of their major allergens Ole e 1 and Par j 1-Par j 2.

BACKGROUND: In patients with pollinosis, allergic symptoms are often correlated with the number of airborne pollen grains, although this correlation is not always close. The direct measurement of the concentration of aeroallergens has only recently been introduced and is an important advance in public health information systems. OBJECTIVE: To compare specific quantification of aeroallergens Ole e 1 and Par j 1-Par j 2 Olea and Urticaceae pollen counts. METHODS: The Hirst method sampler and the Burkard Cyclone sampler were used for pollen count and allergen quantification, respectively. The aerosol was extracted and quantified for Ole e 1 and Par j 1-Par j 2 content using enzyme-linked immunosorbent assay procedures. RESULTS: Day-to-day variations were observed in both the pollen count and the amount of allergens. Pollen counts and aeroallergen quantification were closely correlated with 99% significance (Olea/Ole e 1: R = 0.892, P < .001; Urticaceae/Par j 1-Par j 2: R = 0.734, P < .001). CONCLUSION: The technique for the sampling and quantification of aeroallergens presented in this article, based on enzyme-linked immunosorbent assay and applied to the protein extracts directly obtained from the bioaerosol, represents an important advance in the epidemiologic study of allergic respiratory diseases.     

Seasonal asthma caused by airborne Platanus pollen

This work describes three patients suffering from bronchial asthma after being naturally exposed to airborne plane-tree pollen. The three patients gave immediate response in skin tests and dual response in bronchial provocations using Platanus hybrida extract. There was specific seric IgE activity against this/these antigen(s) with the CAP system. The three patients also showed significant correlation (P < 0·001) between their rhinitis and asthma symptom-scores registered on their diary cards and plane-tree pollen counts, collected using the Burkard spore trap. Among 187 patients living in Madrid and who came to our centre with a history of rhinitis and/or seasonal asthma, we found a prevalence of positive skin-prick tests to Platanus of 56%, only surpassed by gramineous pollen (Dactylis glomerata and/or Trisetum paniceum) 92% and Olea europaea 63%. The aerobiological sampling of the pollen content of the air in Madrid, carried out between 1 January 1979 and 31 December 1993 revealed an airborne presence (per cent of total yearly pollen count, mean of 1979–1993) of 14·9% for the Platanus, 14·8% for grasses, 9·8% for Olea and 3·6% for Plantago. The Platanus is one of the most frequently found pollens in the atmosphere over Madrid. At present, in this geographical area, a high percentage of patients with pollinosis are sensitive to this pollen. At least in some of these patients Platanus pollen is capable of inducing rhinitis and bronchial asthma.     

Release of allergen-bearing cytoplasm from hydrated pollen: a mechanism common to a variety of grass (Poaceae) species revealed by electron microscopy.

BACKGROUND: The release of submicronic particles from grass pollen after rainfall was suggested to be responsible for outbreaks of grass pollen asthma. Recently, we provided evidence for the release of respirable allergen-bearing particles from hydrated ryegrass (Lolium perenne ) pollen as a possible explanation for this phenomenon. OBJECTIVE: We investigated whether water-induced release of respirable allergen-bearing particles could be a mechanism common to several members of the sweet grass family Poaceae (Gramineae). METHODS: Pollens from 6 different Poaceae species were hydrated in water and examined by means of scanning electron microscopy for release of cytoplasmic materials. Rabbit antisera raised against purified recombinant group 1 and 5 allergens were used for immunogold labeling of expelled materials by means of field emission scanning electron microscopy. In addition, group 1 and 5 allergens were immunogold-localized on ultrathin sections. RESULTS: Fresh Poaceae pollens expelled cytoplasmic materials containing group 1 and 5 allergens on hydration in water. Expulsion of submicronic particles strongly decreased after 1 month of storage. CONCLUSIONS: Our results suggest expulsion of cytoplasm after hydration as a mechanism common to pollens of important allergenic grasses. The water-induced release of respirable allergen-bearing particles from grass pollens might explain asthma attacks observed after rainfall during the grass pollen season.     

Air pollution and seasonal asthma during the pollen season. A cohort study in Puertollano and Ciudad Real (Spain)

BACKGROUND: Many studies have demonstrated a positive association between air pollutants and emergency visits for asthma. However, few studies have included pollen when analysing this relationship in mild-moderate asthmatic patients. OBJECTIVE: To determine the importance of the pollutants such as ozone (O(3)), particles (PM(10)), nitrogen dioxide (NO(2)) and sulphur dioxide (SO(2)) in the clinical course of mild-moderate pollen-allergic asthmatic patients from two Spanish towns in La Mancha: Puertollano (high pollution levels) and Ciudad Real (low pollution levels). METHODS: We used a Poisson regression model to study a cohort of 137 patients from Puertollano and Ciudad Real during two pollen seasons (2000-2001) and analysed the relationship between air pollutant and pollen levels and daily symptoms, the medication used and peak-flow measurements. RESULTS: The number of asthma symptoms and the mean values of the PM(10), SO(2) and NO(2) levels were higher in Puertollano than in Ciudad Real. In Puertollano, the risk of asthma increased by 6% with a 3-day lag for PM(10), by 8% with a 3-day lag for O(3), by 4% with a 1-day lag for SO(2) and by 15% with a 3-day lag for O(3) when its values exceeded the health threshold (P < 0.05). CONCLUSIONS: The air pollution levels in Puertollano were associated with an increased risk of asthma symptoms in pollen-allergic asthmatic patients com pared with a similar group from Ciudad Real.     

Omalizumab,a recombinant humanized anti-IgE antibody,reduces asthma-related emergency room visits and hospitalizations in patients with allergic asthma

BACKGROUND: Prevention of serious asthma exacerbations is an important therapeutic goal in patients with asthma. OBJECTIVE: The purpose of this study was to investigate the effect of omalizumab (Xolair), a recombinant humanized monoclonal anti-IgE antibody, on the rate of serious exacerbations during long-term therapy. METHODS: A pooled analysis was completed of 3 multicenter, randomized, double-blind, placebo-controlled phase III studies with omalizumab in adults/adolescents aged > or =12 years (n = 1071) and in children aged 6 to 12 years (n = 334) who required treatment with inhaled corticosteroids for allergic asthma. Rates of serious asthma exacerbations were computed and compared between omalizumab- and placebo-treated patients. Serious exacerbations were those leading to unscheduled outpatient visits, emergency room treatment, or hospitalization during 1 year of treatment. RESULTS: In all, 767 patients were treated with omalizumab (at least 0.016 mg/kg/IgE [IU/mL], administered subcutaneously every 4 weeks). Another 638 patients were treated with placebo. The rate of unscheduled, asthma-related outpatient visits was lower for the omalizumab-treated patients than for the placebo-treated patients (rate ratio [95% CI], 0.60 [0.44, 0.81]; P <.01), as were asthma-related emergency room visits (rate ratio [95% CI], 0.47 [0.24, 1.01]; P =.05). Importantly, hospitalizations for asthma were markedly reduced in patients receiving omalizumab (rate ratio [95% CI], 0.08 [0.00, 0.25]; P <.01). CONCLUSION: Omalizumab reduces the rate of serious asthma exacerbations and the need for unscheduled outpatient visits, emergency room treatment, and hospitalization in patients with moderate-to-severe allergic asthma.     

Aeropollen of weeds of the western United States Gulf Coast.

Volumetric air sampling was performed near Corpus Christi, Texas during all of 1988. The most significant weeds releasing airborne pollen, besides the Asteraceae, were the Amaranthaceae and Chenopodiaceae at 14.8% of total pollen captured, which peaked in September and October. Greater pollen capture (74%) occurred from a peak at 11 PM at a time when inversions are frequent to 9 AM than during the period from late morning to 9 PM. Frequency of amaranth-chenopod pollen capture in the western Gulf Coast region showed no relationship with frequencies along the northern and eastern Gulf Coast nor in eastern North America generally, but rather with western North America where these grains have also been sampled at high levels. As in the West, therefore, amaranth-chenopod aeropollen is sufficiently frequent to be a major source of allergens in the western Gulf Coast region. Other weedy plants, Cannabis/Humulus, Rumex, and the Urticaceae (Parieteria/Urtica) each account for only about 1% of the total annual pollen shed, and consequently they are not nearly as potentially relevant here in pollinosis as are the amaranth-chenopods and Asteraceae. Plantago pollen is very infrequently sampled (less than 0.1%) even though several species are common in the area. Acalypha is newly reported as releasing airborne pollen, a genus related to Mercurialis known to release allergenic pollen in Europe.     

Detection of airborne allergen (Ole e 1) in relation to Olea europaea pollen in S Spain

BACKGROUND: In recent years, it has been demonstrated that the air carries not only airborne pollen but also plant particles of smaller size that have allergenic activity, and, being within the respirable range, these particles can trigger rapid attacks in the lower respiratory tract. The study of particles according to size (0.7-40 micro m) could provide valuable information on the real allergenic activity in the atmosphere. OBJECTIVE: The purpose of this study was to analyse the dynamics of airborne Olea europaea pollen in contrast to the allergenic activity of Ole e 1 in the atmosphere. METHODS: The analyses were carried out with a Hirst-type volumetric collector and a cascade impactor simultaneously during the MPS of the olive. The indirect ELISA was used to detect the allergenic activity. The sampling was performed in Granada city centre (S Spain), in the Science Faculty building on the University of Granada from 30 April to 26 June 2005. RESULTS AND CONCLUSIONS: This research demonstrates that both the allergenic activity as well as the pollen particles follow in a similar curve, except in periods before or succeeding the main Olea pollen season. The study of the distribution of the allergenic particles according to their sizes reveals that the highest concentrations are between 3.3 and <0.7 micro m, thus indicating that allergenic activity primarily involves paucimicronic particles.     

Relationship of outdoor air quality to pediatric asthma exacerbations.

BACKGROUND: Although exposure to outdoor air pollutants has been shown to be associated with exacerbations of asthma, there are relatively few admissions for asthma to Cincinnati Children's Hospital, Cincinnati, OH during the summer months when air quality tends to be worst. OBJECTIVE: The objective of this study was to determine the relationship of outdoor air quality parameters to asthma exacerbations in children. METHODS: The number of emergency room visits and hospitalizations for asthma were determined by review of emergency department logs and the hospital computer database. Outdoor air concentrations of ozone, particulates of < 10 microm diameter (PM-10), pollens, and fungal spores were obtained from the Hamilton County Department of Environmental Services. Multiple regression analysis was performed, looking for relationships between the daily number of asthma visits and the air quality data for the same day and for 1 through 5 days before the visits. RESULTS: A significant association was found between the number of asthma visits and the daily pollen count (P = 0.014, SE = 0.001). The effect was stronger for visits 1, 2, and 3 days after the pollen count (P < 0.001 for pollen count lagged 3 days). High PM-10 counts were synergistic with the pollen count as a predictor of asthma visits. There was no association between asthma visits and the ozone concentration or fungal spore count. CONCLUSIONS: Exacerbations of asthma severe enough to require visits to the hospital were associated with elevated concentrations of airborne pollens and particulates, with a significant delayed effect. Ozone, in the concentrations measured here, was not a risk factor for severe asthma exacerbations in children.     

Analysis of the relationships between environmental factors (aeroallergens, air pollution, and weather) and asthma emergency admissions to a hospital in Mexico City

There have been several studies of the relationships between environmental factors, particularly air pollution, and attacks of asthma. Most of these studies have ignored the potential confounding effects of aeroallergens such as pollens and fungal spores. We report a statistical analysis of the relationships between emergency admissions for asthma to a hospital in Mexico City and daily average airborne concentrations of pollen, fungal spores, air pollutants (O₃, NO₃, SO₃. and particulates) and weather factors. Asthma admissions had a seasonal pattern with more during the wet season (May-October) than the dry season (November-April). There were few statistical associations between asthma admissions and air pollutants for the three age groups studied (children under 15 years, adults, and seniors [adults over 59 years]) in either season. Grass pollen was associated with child and adult admissions for both the wet and dry seasons, and fungal spores were associated with child admissions during both the wet and dry seasons. The analysis was done with environmental data averaged over the day of admission and the 2 previous days. Our results suggest that aeroallergens may be statistically associated more strongly with asthma hospital admissions than air pollutants and may act as confounding factors in epidemiologic studies.     

Trisetum paniceum (wild oats) pollen counts and aeroallergens in the ambient air of Madrid,Spain

BACKGROUND: Madrid has a short but intensive grass pollen season, in which 79% of the total grass pollen load is released from the middle of May to the middle of June. The main objectives of this study were to quantify Trisetum paniceum (wild oats) aeroallergen in the atmosphere in Madrid from February to December 1996 and to correlate the aeroallergen concentrations with grass pollen counts. METHODS: Two different samplers were used to assess allergen exposure; a Burkard spore trap was used to collect pollen grains and a high-volume air sampler to collect airborne particles. A total of 182 air filters were collected and extracted in 1 ml of PBS and analysed by ELISA inhibition, using pooled sera from highly allergic individuals. RESULTS: T. paniceum aeroallergens were detected not only during the grass pollen season, but also before and after. Wild oat allergens had two main peaks of 1 and 1.9 microg/m(3), occurring in late May and July, respectively. The time series analysis established the existence of lags between the two main variables pollen counts and aeroallergen activity. Analysis of the data by the Spearman rank test and linear regression showed a weak correlation between grass allergenic activity and grass pollen counts (Spearman's rho = 0.29). Data obtained from time series analysis demonstrated that grass allergenic activity correlated strongly with current and 5-week-old grass pollen grain counts (r(2) = 0.73). CONCLUSIONS: Wild oats allergenic activity was detected during the entire year and not only during the pollen season. This fact is an important aspect to be considered in the clinical follow-up and treatment of grass pollen-sensitised patients in Madrid.     

Effects of air pollution on asthma hospitalization rates in different age groups in Hong Kong

AIMS: To assess the relationship between levels of ambient air pollutants and hospitalization rates for asthma in Hong Kong (HK). METHODS: This is a retrospective ecological study. Data of daily emergency hospital admissions to 15 major hospitals in HK for asthma and indices of air pollutants [sulphur dioxide (SO(2)), nitrogen dioxide (NO(2)), ozone (O(3)), particulates with an aerodynamic diameter of <10 microm particulate matter (PM(10)) and 2.5 microm (PM(2.5))] and meteorological variables from January 2000 to December 2005 were obtained from several government departments. Analysis was performed by the generalized additive models with Poisson distribution. The effects of time trend, season, other cyclical factors, temperature and humidity were adjusted. Autocorrelation and overdispersion were corrected. RESULTS: Altogether, 69 716 admissions were assessed. Significant associations were found between hospital admissions for asthma and levels of NO(2), O(3), PM(10) and PM(2.5). The relative risks (RR) for hospitalization for every 10 microg/m(3) increase in NO(2), O(3), PM(10) and PM(2.5) were 1.028, 1.034, 1.019 and 1.021, respectively, at a lag day that ranged from cumulative lag 0-4 to 0-5. In a multi-pollutant model, O(3) was significantly associated with increased admissions for asthma. The younger age group (0-14 years) tended to have a higher RR for each 10 microg/m(3) increase in pollutants than those aged 15-65 years. The elderly (aged >/=65 years) had a shorter 'best' lag time to develop asthma exacerbation following exposure to pollutants than those aged <65 years. CONCLUSION: Adverse effects of ambient concentrations of air pollutants on hospitalization rates for asthma are evident. Measures to improve air quality in HK are urgently needed.     

Predictors of asthma-related health care utilization and quality of life among inner-city patients with asthma

BACKGROUND: Asthma morbidity and mortality are highest among minority inner-city populations. OBJECTIVE: To identify factors associated with acute health care resource utilization and asthma-related quality of life among high-risk, minority patients with asthma. METHODS: We interviewed a prospective cohort of 198 adults hospitalized for asthma in an inner city hospital over a period of 1 year. Detailed information about sociodemographics, asthma history, access to care, asthma medications, and self-reported allergy to aeroallergens was collected at baseline. Data on resource utilization (emergency department visits and hospital admissions for asthma) and asthma-related quality of life were obtained at 6 months after discharge. Multivariate analyses were used to identify predictors of resource utilization and quality of life. RESULTS: The mean age of patients was 49.9 +/- 17.4 years, 78% were women, and 97% were nonwhite. At 6 months, 49% of patients had an emergency department visit or hospitalization. In multivariate analysis, adjusting for age, sex, medication regimen, and asthma severity, patients with a physician in charge of their asthma care had lower odds of resource utilization (odds ratio, 0.4; P=.03). Conversely, a self-reported history of cockroach allergy was associated with greater utilization (odds ratio, 2.3; P=.05). Asthma-related quality of life was worse among patients who spoke mostly Spanish or who reported allergy to cockroaches (P < .004). CONCLUSION: Lack of an established asthma care provider, language barriers, and self-reported allergy to cockroaches are associated with higher resource utilization and worse quality of life among minority, inner-city patients with asthma. Interventions targeting these factors may lead to better outcomes among these patients.