The September epidemic of asthma hospitalization: school children as disease vectors

Environmental factors affecting seasonality of ambulance emergency service visits for exacerbations of asthma and COPD

OBJECTIVE

The aim of this study was to assess the association of severe exacerbations of asthma and Chronic Obstructive Pulmonary Disease (COPD) requiring ambulance emergency service (AES) visits with meteorological parameters and influenza outbreaks.

METHODS

The records of patients calling the AES in 2007 and 2008 in the urban area of Lodz due to dyspnea were analyzed. Information on 25 daily reported meteorological parameters was obtained from the local meteorological service and data on influenza outbreaks obtained from the national surveillance service.

RESULTS

During the winter months, a significantly higher mean daily number of AES visits for both COPD and asthma were noticed when compared to the summer. Interestingly, the number of daily AES visits correlated with several weather parameters, and the multiple regression analysis confirmed a negative correlation with minimum temperature, mean temperature and the dew point for both diseases (R = 0.526; p < 0.01; R = 0.577; p < 0.01 and R = 0.589; p < 0.01). Furthermore, the increased number of AES visits also correlated with a new number of cases of influenza infections as reported by local influenza surveillance system (rs = 77.6%; p < 0.001 and rs = 80.8%; p < 0.001 for asthma and COPD, respectively).

CONCLUSION

Seasonality of AES visits for asthma and COPD are similar and seems to be related to specific weather conditions and to influenza outbreaks.

Hospitalizations and outpatient visits for rhinovirus-associated acute respiratory illness in adults

BACKGROUND

Rhinovirus is linked to asthma exacerbations and chronic obstructive pulmonary disease exacerbations in adults. The severity and rates of rhinovirus acute respiratory illnesses (ARIs) in adults are uncertain.

OBJECTIVES

We sought to determine rhinovirus-associated ARI rates in adults presenting for care in multiple settings and identify factors associated with rhinovirus detection.

METHODS

This prospective, population-based cohort enrolled Tennessee residents 18 years or older in the emergency department (ED), outpatient clinics, or hospitalized for ARI from December 2008 to May 2010. Nasal/throat swabs were collected and tested for rhinovirus and other viruses by using RT-PCR. Rates of ED visits and hospitalizations were calculated and rhinovirus-positive and rhinovirus-negative patients were compared.

RESULTS

Among 2351 enrollees, rhinovirus was detected in 247 (11%). There were 7 rhinovirus-associated ED visits and 3 hospitalizations per 1000 adults annually. Patients with rhinovirus, compared with virus-negative ARI, were more likely to present with wheezing (odds ratio [OR], 1.7; 95% CI, 1.23-2.35; P < .001), to be a current smoker (OR, 2.31; 95% CI, 1.68-3.19) or live with a smoker (OR, 1.72; 95% CI, 1.10-2.67), have a history of chronic respiratory disease (OR, 1.61; 95% CI, 1.17-2.22), and were less likely to be hospitalized versus seen in the outpatient setting (OR, 0.58; 95% CI, 0.41-0.83).

CONCLUSIONS

Rhinovirus is associated with a substantial number of ED visits and hospitalizations for ARIs in adults. There may be modifiable factors that can reduce the likelihood of presenting with rhinovirus-associated ARIs.

Back-to-school upper respiratory infection in preschool and primary school-age children in Israel

BACKGROUND

Increased upper respiratory infection (URI) among children at the beginning of school year is well known to parents and pediatricians. However, this phenomenon is not well documented or characterized.

METHODS

Computerized datasets from a large health maintenance organization in Israel were used to calculate the weekly rates of URI among children 3-14 years old for the years 2007-2012. In addition, nasopharyngeal swabs were collected in 2010-2012 from children with URI symptoms and controls during school opening time. Swabs were tested by real-time polymerase chain reaction for the presence of respiratory viruses.

RESULTS

Time-series analysis demonstrated a peak of URI in September each year. The peaks reached their height 2 weeks after school opening and returned to baseline within 4-7 weeks. The main 3 viruses detected both in URI patients and in healthy controls during the first weeks of school opening were rhinovirus, adenovirus and enterovirus. The detection rate of any respiratory virus, and of rhinovirus in particular, was significantly higher among cases than among controls (54% vs. 16%, P < 0.001 for any virus, and 35% vs. 6.0%, P < 0.01 for rhinovirus). When adjusting for age and sex cases had 5.8 times more viral detection when compared with controls. Upper respiratory symptoms were significantly more prevalent among the virus-positive cases when compared with negative ones.

CONCLUSIONS

Back-to-school illness consisting of URI has a distinct epidemiological pattern demonstrating a rapid rise peaking within 2 weeks of school opening and is associated predominantly with rhinovirus.

Can meteorological factors forecast asthma exacerbation in a paediatric population?

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The effect of the weather on pulmonary exacerbations and viral infections among adults with cystic fibrosis

The effect of changes in the weather on the respiratory health of patients with cystic fibrosis (CF) is unclear. We conducted a prospective study to determine the impact of climate and season on the incidence of viral respiratory infections (VRI) and pulmonary exacerbations (PEx) among adults with CF. Between December 2010 and April 2012, 98 adults with CF were followed for 12 months. Polymerase chain reaction assays for nine viruses were performed on sputum, nose and throat swabs every 2 months and additionally at onset of PEx. Hourly temperature and relative humidity measurements were recorded throughout the study. Statistical analysis utilized generalized estimating equation (GEE) models. Pre-specified criteria for VRI and PEx were met at 29% and 37% of visits, respectively. Rhinovirus accounted for 72% of identified viruses. Incidence of rhinovirus peaked in autumn while non-rhinovirus VRI peaked in winter. Rhinovirus was associated with increased mean temperatures (OR 1.07; p = 0.001), while non-rhinovirus VRI was associated with lower mean temperatures (OR 0.87; p < 0.001). PEx occurred frequently throughout the study with no clear seasonal pattern observed. There was no significant association between climate variables and the incidence of either PEx or antibiotic prescription. There is a seasonal pattern to VRI in adults with CF. The incidence of VRI but not PEx is associated with changes in ambient temperature.

Seasonality of asthma: a retrospective population study

OBJECTIVES

Seasonal variations in asthma are widely recognized, with the highest incidence during September. This retrospective population study aimed to investigate whether this holds true in a large group of asthmatic children in primary care and to assess the impact of age, gender, urban/rural living, and population sector.

METHODS

The key study outcomes were the diagnosis of asthma exacerbations and asthma medication prescriptions, recorded by family physicians during 2005 to 2009. These were analyzed by "week of diagnosis" in Clalit Health Services' electronic medical record database. Regression models were built to assess relative strength of secular trends, seasonality, and age-group in explaining the incidence of asthma exacerbations.

RESULTS

A total of 919,873 children aged 2 to 15 years were identified. Of these, 82,234 (8.9%) were asthmatic, 61.6% boys and 38.4% girls; 49.1% aged 2 to 5 years, 24.1% 6 to 9 years, and 26.8% 10 to 15 years. We observed a 2.01-fold increase in pediatric asthma exacerbations and 2.28-fold increase in prescriptions of asthma bronchodilator medications during September (weeks 37-39 vs weeks 34-36) compared with August. The association between the opening of school and the incidence of asthma-related visits to the primary care physician was greatest in children aged 2 to 5 years (odds ratio, 2.15) and 6 to 11 years (1.90-fold). Adolescents (age 12-15 years) had a lesser peak (1.81-fold). In late fall there was a second rise, lasting with fluctuations throughout winter, with a trough in summer.

CONCLUSIONS

Returning to school after summer is strongly associated with an increased risk for asthma exacerbations and unscheduled visits to the primary care physician.

Asthma exacerbations: predisposing factors and prediction rules

PURPOSE OF REVIEW

Asthma is a multifaceted disease that is associated with decreased lung function, multiple symptoms, varying levels of asthma control, and risk of acute exacerbations. The ability to predict the risk of developing acute exacerbations may improve the management of asthmatics and facilitate identification of these patients for interventional studies.

RECENT FINDINGS

Factors that are associated with different manifestations of asthma differ. Biomarkers that are correlated with airways hyper-responsiveness do not necessarily correlate with risk of future exacerbations. Genetic factors that segregate with exacerbation risk are beginning to emerge. Outcome measures that demonstrate predictive validity have been developed and may facilitate patient management and provide novel clinically meaningful endpoints in clinical trials.

SUMMARY

This review will emphasize underlying factors associated with asthma exacerbations and clinical prediction rules that correlate with the risk of developing severe exacerbations of asthma.

Reactive versus proactive patterns of inhaled corticosteroid use

For patients with persistent asthma, inhaled corticosteroids (ICS) are a mainstay of controller therapy. These medications are usually prescribed to be taken daily and have been shown to be associated with decreased asthma morbidity. Adherence to daily treatment is very low in many populations in the United States. The purpose of this study is to evaluate the seasonal use of ICS prescription filling as reactive behavior primarily after an asthma exacerbation in a pediatric population. The study population is a subgroup of the Tennessee Asthma and Bronchiolitis Study. The children in this study were enrolled in Tennessee Medicaid (TennCare). The subjects had asthma and were 6 to 9 years of age during the years 2005 to 2010. Prescription filling was determined using claims data, and asthma exacerbations were defined by use of systemic rescue corticosteroids (RCS). In this cohort of 13,114 children with asthma, ICS and RCS filling were highly seasonal and trended with fall and winter peaks in asthma exacerbations. Prescription refilling was very low, with an average of three ICS fills per child who filled at least one during the study period. Among these children, 54.1% (7,096) had an asthma exacerbation during the study period. Among ICS users, 68.5% (3,441/5,020) had a disease exacerbation. ICS filling occurred overwhelmingly on the same day as RCS fills. The seasonal filling patterns of ICS coincide with asthma exacerbations. ICS adherence is low and inconsistent in this population of children with asthma. Increased adherence to ICS, particularly before the seasonal virus epidemics, could greatly reduce asthma morbidity.

Effect of exogenous interferons on rhinovirus replication and airway inflammatory responses

BACKGROUND

Human rhinoviruses (HRVs) are the most common cause of asthma exacerbations. In airway epithelial cells, the primary site of HRV infection, decreased production of interferons (IFNs) may result in greater susceptibility to HRV and worsened symptoms. Thus, exogenous IFN could supplement the innate immune response and provide a treatment for virus-induced asthma exacerbations. Furthermore, the effects of exogenous IFN could be type specific in part because of the cellular distribution of type 1 and type 2 IFN receptors.

OBJECTIVE

To investigate the effects of exogenous IFNs on HRV replication in bronchial epithelial cells.

METHODS

Frozen stocks of primary human bronchial epithelial cells from healthy donors were cultured in monolayers; pretreated (24 hours) with 0.1-ng/mL, 1-ng/mL, or 10-ng/mL doses of IFN-α, -β, -λ1, or -λ2; and infected with HRV-1A. Viral replication was quantified using real-time reverse transcription-polymerase chain reaction, and cytokine and chemokine secretion 24 hours after infection was measured by multiplex enzyme-linked immunosorbent assay.

RESULTS

Compared with untreated samples, IFN-α, IFN-β, IFN-λ1, and IFN-λ2 (0.1 ng/mL) significantly reduced HRV replication after high- (P < .02) and low-dose inoculation (P < .05). Similar effects were seen in 1-ng/mL and 10-ng/mL doses of IFN, where HRV replication was significantly decreased in both high- (P < .001) and low-dose inoculation (P < .001). Treatment with IFNs also enhanced HRV-induced IFN-γ-induced protein 10 secretion (P < .001). Finally, treatment with either IFN-λ1 or IFN-λ2 significantly increased HRV-induced secretion of RANTES (regulated on activation, normal T-expressed, and presumably secreted) (P < .05) but not IL-1β or vascular endothelial growth factor.

CONCLUSION

These findings suggest that exogenous IFNs, IFN-λ1 in particular, warrant further study as a potential therapy for virus-induced asthma exacerbations.

Virus/allergen interactions in asthma

Understanding the underlying mechanisms that cause and exacerbate allergic asthmatic disease is of great clinical interest. Clinical studies have revealed that allergies and viral respiratory illnesses are strongly linked to the inception and exacerbation of asthma, and suggest the possibility that there are interactive inflammatory mechanisms. Recent work has revealed a number of mechanisms of virus and allergen cross-talk that may play a role in the pathophysiology of allergic asthma, including (1) deficiency in virus-induced interferon responses, (2) defective epithelial barrier function, (3) increased release of epithelium-derived cytokines (e.g., thymic stromal lymphopoietin (TSLP), interleukin (IL)-25, IL-33), (4) dysregulation of lymphocytes [e.g., innate lymphoid cells (ILCs), regulatory T cells (Tregs)], and (5) altered activation of purinergic receptors. One or more of these processes may provide targets for new therapeutics to treat allergic asthma and prevent disease exacerbation.

Modulation of transcriptional responses by poly(I:C) and human rhinovirus: effect of long-acting β₂-adrenoceptor agonists

Exacerbations of asthma, a chronic inflammatory respiratory disease, are associated with viral upper respiratory tract infections involving human rhinovirus. Although glucocorticoids (corticosteroids) effectively control airways inflammation in many asthmatics, human rhinovirus-associated exacerbations show reduced glucocorticoid responsiveness. Using human bronchial epithelial BEAS-2B cells, we show that human rhinovirus reduced glucocorticoid-inducible activation of glucocorticoid response element (GRE) reporter systems in a time- and concentration-dependent manner. The synthetic double-stranded viral RNA mimetic, polyinosinic:polycytidylic acid (poly(I:C)), also reduced activation of GRE reporter systems in BEAS-2B and pulmonary A549 cells. In addition, poly(I:C) decreased transcription from cAMP response element (CRE)-, TATA-, simian virus 40- and nuclear factor-kappa B (NF-κB)-dependent reporter systems. The effects of poly(I:C) on GRE-reporter activation were countered by the long-acting β2-adrenoceptor agonists, formoterol and salmeterol. Likewise, increased expression of the gene cyclin-dependent kinase inhibitor 1C (CDKN1C; p57(KIP2)) by dexamethasone was reduced by poly(I:C), but was substantially enhanced by the addition of formoterol. Poly(I:C) induced the expression of interleukin-8 (IL8; CXCL8) and this was significantly decreased by dexamethasone, formoterol or their combination. This confirms that not all transcriptional responses were attenuated by poly(I:C) and that decreased glucocorticoid-dependent transcription can be counteracted by the addition of long-acting β2-adrenoceptor agonists. These data show how human rhinovirus may attenuate glucocorticoid-induced transcription to reduce anti-inflammatory activity. However, addition of long-acting β2-adrenoceptor agonist to the glucocorticoid functionally restored this response and shows how glucocorticoid plus long-acting β2-adrenoceptor agonist combinations may prove beneficial during virus-induced exacerbations of asthma.

Associations between pollen counts, pollutants, and asthma-related hospital admissions in a high-density Indian metropolis

BACKGROUND

The seasonal pattern of asthma-related hospitalization has often been correlated with ambient allergen/pollutant levels.

OBJECTIVE

To examine the relationship between asthma-related hospital admissions (ARHA) and outdoor pollen, spore, and pollutant levels for adult patients in a densely populated Indian megacity Kolkata.

METHODS

ARHA data were obtained from two major teaching hospitals of the city. Pollen and spores causing allergic sensitization were identified by skin prick tests (SPTs) among respiratory allergic subjects (N = 1353). Outdoor concentrations of aeroallergens were determined using a Burkard sampler for five consecutive years (2004-2009). Levels of NO(2), SO(2), suspended particulate matters (SPMs), and respirable particulate matters (RPMs) were made available by West Bengal Pollution Control Board (WBPCB, Government of West Bengal). Poisson multivariate Poisson regression (with adjustments for overdispersion) was used to model the data. Results. We found that ARHA in Kolkata increased with predictable regularity in March and September, while remaining low in January and July. SPT showed highly positive skin reactions with grass/weed and palm pollens in respiratory allergic patients, while Aspergilli spores also evoked good sensitivity. In our regression model, the airborne pollen types, Cheno-Amaranthaceae and Cyperaceae, and the inorganic pollutant, SO(2) and RPM, were significantly associated with ARHA (p < .05).

CONCLUSION

ARHA in the megacity of Kolkata shows two seasonal peaks that can be correlated with outdoor grass/weed pollen and RPM concentrations. In contrast, the city's ambient fungal spore counts were not found to be significantly associated.

The effects of indoor environmental exposures on pediatric asthma: a discrete event simulation model

BACKGROUND

In the United States, asthma is the most common chronic disease of childhood across all socioeconomic classes and is the most frequent cause of hospitalization among children. Asthma exacerbations have been associated with exposure to residential indoor environmental stressors such as allergens and air pollutants as well as numerous additional factors. Simulation modeling is a valuable tool that can be used to evaluate interventions for complex multifactorial diseases such as asthma but in spite of its flexibility and applicability, modeling applications in either environmental exposures or asthma have been limited to date.

METHODS

We designed a discrete event simulation model to study the effect of environmental factors on asthma exacerbations in school-age children living in low-income multi-family housing. Model outcomes include asthma symptoms, medication use, hospitalizations, and emergency room visits. Environmental factors were linked to percent predicted forced expiratory volume in 1 second (FEV1%), which in turn was linked to risk equations for each outcome. Exposures affecting FEV1% included indoor and outdoor sources of NO2 and PM2.5, cockroach allergen, and dampness as a proxy for mold.

RESULTS

Model design parameters and equations are described in detail. We evaluated the model by simulating 50,000 children over 10 years and showed that pollutant concentrations and health outcome rates are comparable to values reported in the literature. In an application example, we simulated what would happen if the kitchen and bathroom exhaust fans were improved for the entire cohort, and showed reductions in pollutant concentrations and healthcare utilization rates.

CONCLUSIONS

We describe the design and evaluation of a discrete event simulation model of pediatric asthma for children living in low-income multi-family housing. Our model simulates the effect of environmental factors (combustion pollutants and allergens), medication compliance, seasonality, and medical history on asthma outcomes (symptom-days, medication use, hospitalizations, and emergency room visits). The model can be used to evaluate building interventions and green building construction practices on pollutant concentrations, energy savings, and asthma healthcare utilization costs, and demonstrates the value of a simulation approach for studying complex diseases such as asthma.

Ambient pollen concentrations and emergency department visits for asthma and wheeze

BACKGROUND

Previous studies report associations between aeroallergen exposure and asthma exacerbations. Aeroallergen burdens and asthma prevalence are increasing worldwide and are projected to increase further with climate change, highlighting the importance of understanding population-level relationships between ambient pollen concentrations and asthma.

OBJECTIVE

We sought to examine short-term associations between ambient concentrations of various pollen taxa and emergency department (ED) visits for asthma and wheeze in the Atlanta metropolitan area between 1993 and 2004.

METHODS

We assessed associations between the 3-day moving average (lag 0-1-2) of Betulaceae (except Alnus species), Cupressaceae, Quercus species, Pinaceae (except Tsuga species), Poaceae, and Ambrosia species pollen concentrations and daily asthma and wheeze ED visit counts, controlling for covarying pollen taxa and ambient pollutant concentrations.

RESULTS

We observed a 2% to 3% increase in asthma- and wheeze-related ED visits per SD increase in Quercus species and Poaceae pollen and a 10% to 15% increased risk on days with the highest concentrations (comparing the top 5% of days with the lowest 50% of days). An SD increase in Cupressaceae concentrations was associated with a 1% decrease in ED visits. The association for Quercus species pollen was strongest for children aged 5 to 17 years. Effects of Ambrosia species pollen on asthma exacerbations were difficult to assess in this large-scale temporal analysis because of possible confounding by the steep increase in circulating rhinoviruses every September.

CONCLUSION

Poaceae and Quercus species pollen contribute to asthma morbidity in Atlanta. Altered Quercus species and Poaceae pollen production caused by climate change could affect allergen-induced asthma morbidity in the southeastern United States.

The Christmas season as a risk factor for chronic obstructive pulmonary disease exacerbations

BACKGROUND

Epidemics of hospitalization for chronic obstructive pulmonary disease (COPD) occur annually during the Christmas holidays, and COPD exacerbations commonly coincide with respiratory viral infections.

OBJECTIVE

To compare the incidence and determinants of COPD exacerbations occurring between the Christmas holiday period and the remainder of the winter season.

METHODS

Seventy-one subjects with COPD of mixed severity faxed daily symptom diaries to a computer monitoring system from December 1, 2006, to April 30, 2007. Possible exacerbations prompted a home visit for assessment, spirometry and specimen collection for virological testing.

RESULTS

Study subjects submitted a total of 95.4% of possible daily symptom diary sheets by fax. Of 114 possible COPD exacerbations detected using the faxed diaries, 110 met the Anthonisen criteria for true exacerbations. A total of 47 exacerbations (mean 6.7/week) occurred during the Christmas holiday period, while 63 exacerbations (mean 4.3/week) occurred during the remainder of winter. Of the Christmas period exacerbations and of those in the balance of winter, 21 (44%) and 20 (32%), respectively, coincided with respiratory viral infections.

CONCLUSIONS

The incidence of COPD exacerbations during the Christmas period was greater than during the rest of winter in 2006/2007 and peaked immediately before Christmas - in contrast to hospital presentation for COPD, which peaked during the Christmas week. No clear role of respiratory viral infections in the increased rate of exacerbations during the Christmas period was established in the present study. COPD patients were highly compliant with daily symptom reporting using faxed daily diaries, which permitted nearly complete detection of all exacerbations that occurred at incidence.

[Knowledge, attitudes and asthma quality of life of adolescents in schools. The need to educate our teaching centres]

INTRODUCTION

Knowledge and attitudes toward asthma can condition the integration of adolescents with asthma in school and affect their quality of life. Our objective was to determine the state of knowledge, attitudes on asthma in secondary schools, and its relationship to quality of life of pupils with asthma, as an early step to an educational intervention.

METHODS

Descriptive and cross-sectional study of pupils aged 13 and 14 years old and their teachers in 26 schools of Seville and province. We used, as study tools, the Newcastle Asthma Knowledge Questionnaire, the Gibson attitudes towards asthma, and the Paediatric Asthma Quality of Life Questionnaire. To assess the normality of variables, the Kolmogorov-Smirnov test was used, and for non-parametric variables the U Mann-Whitney and W Wilcoxon tests were used. For the association between variables, we use the regression coefficients and rho Spearman.

RESULTS

We studied 3827 pupils (279 with asthma) and 548 teachers. All had little knowledge about asthma. The quality of life in asthma was mild to moderately affected, and lower in girls, 5.38±1.08 (95% CI=5.20 to 5.55) than in boys 5.77 (± 1.18) (95% CI=5.56 to 5.97), P=.0000. We found no relationship between knowledge, attitudes and quality of life in asthma.

CONCLUSIONS

We found a low level of knowledge about asthma in pupils and teacher. Asthma sufferers have a mild to moderate asthma quality of life, which is worse for girls. Knowledge has no relationship with attitudes to asthma in all groups, or with the quality of life of asthma sufferers.

Asthma exacerbations: origin, effect, and prevention

Asthma is the most common chronic respiratory disease, affecting up to 10% of adults and 30% of children in the Western world. Despite advances in asthma management, acute exacerbations continue to occur and impose considerable morbidity on patients and constitute a major burden on health care resources. Respiratory tract viruses have emerged as the most frequent triggers for exacerbations in both children and adults; however, the mechanisms underlying these remain poorly understood. More recently, it has become increasingly clear that interactions might exist between viruses and other triggers, increasing the likelihood of an exacerbation. In this article we begin with an overview of the health, economic, and social burden that exacerbations of asthma carry with them. This is followed by a review of the pathogenesis of asthma exacerbations, highlighting the various triggers responsible and multiple interactions that exist between them. The final section first addresses what preventative measures are currently available for asthma exacerbations and subsequently examines which of the new treatments in development might lessen the burden of exacerbations in the future.

Asthma diagnosis and treatment: filling in the information gaps

Current approaches to the diagnosis and management of asthma are based on guideline recommendations, which have provided a framework for the efforts. Asthma, however, is emerging as a heterogeneous disease, and these features need to be considered in both the diagnosis and management of this disease in individual patients. These diverse or phenotypic features add complexity to the diagnosis of asthma, as well as attempts to achieve control with treatment. Although the diagnosis of asthma is often based on clinical information, it is important to pursue objective criteria as well, including an evaluation for reversibility of airflow obstruction and bronchial hyperresponsiveness, an area with new diagnostic approaches. Furthermore, there exist a number of treatment gaps (ie, exacerbations, step-down care, use of antibiotics, and severe disease) in which new direction is needed to improve care. A major morbidity in asthmatic patients occurs with exacerbations and in patients with severe disease. Novel approaches to treatment for these conditions will be an important advance to reduce the morbidity associated with asthma.

Rhinoviruses, allergic inflammation, and asthma

Viral infections affect wheezing and asthma in children and adults of all ages. In infancy, wheezing illnesses are usually viral in origin, and children with more severe wheezing episodes are more likely to develop recurrent episodes of asthma and to develop asthma later in childhood. Children who develop allergen-specific immunoglobulin E (allergic sensitization) and those who wheeze with human rhinoviruses (HRV) are at especially high risk for asthma. In older children and adults, HRV infections generally cause relatively mild respiratory illnesses and yet contribute to acute and potentially severe exacerbations in patients with asthma. These findings underline the importance of understanding the synergistic nature of allergic sensitization and infections with HRV in infants relative to the onset of asthma and in children and adults with respect to exacerbations of asthma. This review discusses clinical and experimental evidence of virus-allergen interactions and evaluates theories which relate immunologic responses to respiratory viruses and allergens to the pathogenesis and disease activity of asthma. Greater understanding of the relationship between viral respiratory infections, allergic inflammation, and asthma is likely to suggest new strategies for the prevention and treatment of asthma.

A modern miasma hypothesis and back-to-school asthma exacerbations

A sudden increase in the rate of asthma exacerbations has been observed among young children in many countries 2-3 weeks after their return-to-school following the summer holidays. These exacerbations are frequently associated with human rhinovirus (hRV) infections, with possible interactions with allergen sensitisation, allergen exposure and medication use. It was originally proposed that the sudden increase resulted from new strains of respiratory viruses acquired during the holidays spreading rapidly on return to school. While there is compelling evidence implicating hRV in these exacerbations, recent observations on virus transmission, infection patterns and immune responses to both viruses and allergens have led us to propose an additional hypothesis for this increase in exacerbations. We propose that classrooms typically provide persistent exposure to a mixture of airborne viruses, viral proteins, endotoxin, community allergens and other human-derived aerosols - a modern miasma. During the preceding school term, this exposure establishes and maintains a level of immune tolerance and herd immunity, which then declines during the two-month holidays due to lack of such exposure, creating a transitory window of susceptibility to viral infections and asthma. The return to school re-establishes exposure to these aerosols resulting in an acceleration of exacerbations, until the tolerance and herd immunity are re-established. Thus, the peak in return-to-school asthma is more a function of a transitory increase in susceptibility due to a temporary lack of this complex exposure, than it is to novel, locally endemic strains of hRV.

Absence, extended absence, and repeat tardiness related to asthma status among elementary school children

BACKGROUND

The purpose of this analysis was to examine potential associations between absence, extended (repeated) absence, tardiness, and repeated tardiness from school and doctor-diagnosed asthma.

METHODS

A cross-sectional analysis was conducted using data collected in fall 2007 on 914 4th and 5th grade school children from seven randomly selected participating schools in DeKalb County, GA. ANOVA was used to compare attendance metrics for race, gender, and asthma status groups. Nonparametric Kruskal-Wallis statistical tests were also done because distributions of attendance metrics were skewed. We tallied daily absence data during the study period and examined absence by day of week. We also compared the variation of the weekly rate of absence and tardiness for students with asthma versus students without asthma over the study period.

RESULTS

The mean days of absence in 86 students with asthma was 2.73 days compared with 1.89 days for 828 children without asthma (p = .004). There was no significant difference in mean days of tardiness by asthma status. The difference in the number of instances of 2+ consecutive days of absence (extended absence) by asthma status was not significant. Students with asthma were more likely to be absent on Mondays (p = .005), Tuesdays (p = .001), and Fridays (p = .02) than students without asthma. The weekly rate of tardiness for students with asthma trended with the general student study population over the study period, whereas the weekly rate of absence did not.

CONCLUSIONS

Asthma was associated with increased 1-day absences but not longer absences or tardiness.

Virus/allergen interactions and exacerbations of asthma

Clinical research findings indicate that there are synergistic interactions between allergy and viral infection that cause increased severity of asthma exacerbations. This article summarizes the current literature linking these 2 risk factors for asthma exacerbation, and reviews experimental data suggesting potential mechanisms for interactions between viral infection and allergy that cause asthma exacerbations. In addition, the authors discuss clinical evidence that treatment of allergic inflammation could help to reduce the frequency and severity of virus-induced exacerbations of asthma.

Parent support, peer support, and peer acceptance in healthy lifestyle for asthma management among early adolescents

PURPOSE

This study aims to investigate the association between social support variables and healthy lifestyle for asthma management among early adolescents (ages 9-14 years).

DESIGN AND METHODS

Questionnaires were completed by 86 parent-adolescent dyads.

RESULTS

Healthy lifestyle was associated with social support variables. The association with peer acceptance was stronger among adolescents who received less asthma-specific support from peers. Age was negatively associated with healthy lifestyle, but the association was attenuated after adjustment for asthma-specific peer support.

PRACTICE IMPLICATIONS

The findings of this study suggest recognizing the developmental change of social support during early adolescence.

New human rhinovirus species and their significance in asthma exacerbation and airway remodeling

Asthma is the most common chronic disease of childhood, affecting 10% to 15% of all children. Several different stimuli including allergens, tobacco smoke, certain drugs, and viral or bacterial infections are known to exacerbate asthma symptoms. Among these triggers, viruses are frequent inducers of asthma exacerbations, with human rhinoviruses being the most common in children and adults. This article describes the different species of this virus and their roles as major triggers of asthma exacerbations.

Role of viral respiratory infections in asthma and asthma exacerbations

Viral respiratory tract infections are common and usually selflimited illnesses. For patients at risk of asthma, or with existing asthma, viral respiratory tract infections can have a profound effect on the expression of disease or loss of control. New evidence has shown that wheezing episodes early in life due to human rhinoviruses are a major risk factor for the later diagnosis of asthma at age 6 years. For those with existing asthma, exacerbations are a major cause of morbidity, can need acute care, and can, albeit rarely, result in death. Viral respiratory tract infections, predominantly those caused by human rhinoviruses, are associated with asthma exacerbations. There is also evidence that deficiencies in antiviral activity and the integrity of the airway epithelial barrier could make individuals with asthma more likely to have severe viral respiratory infections of the lower airway, and thus increase the risk of exacerbation. In view of the effect of respiratory viruses on many aspects of asthma, efforts to understand the mechanisms and risk factors by which these airway infections cause changes in airway pathophysiology are a first step towards improved treatment.

Role of rhinovirus C respiratory infections in sick and healthy children in Spain

BACKGROUND

Recently a new genogroup of human rhinovirus (HRV) has been described and named HRV-C. The relative importance of HRV-C in viral respiratory tract illnesses is unknown.

OBJECTIVE

We looked for HRV-C in pediatric patients with respiratory tract infections to determine the incidence of HRV-C and its role in sick and healthy children. We describe the clinical differences associated with HRV-C infections and other HRV genogroups.

PATIENTS AND METHODS

From January 2004 to December 2008, a prospective study was conducted in children younger than 14 years who were admitted with respiratory infection to the Pediatrics Department of the Severo Ochoa Hospital in Madrid, Spain. Specimens of nasopharyngeal aspirate were taken for virologic study with polymerase chain reaction, and clinical data were recorded. HRV specimens were genotyped. We studied the frequency of HRV-C infections, the clinical course of these patients and the differences with other HRV genogroups (HRV-A and HRV-B). Presence of HRV-C was also studied in a group of healthy children.

RESULTS

HRV was detected in 424 of 1555 episodes of illness (27.2%) and in 26 of 211 healthy children (12.3%) (P < 0.001). We amplified at random 248 of them (227 hospitalized children and 21 healthy children): 132 (53.2%) had HRV-A, 28 (11.2%) had HRV-B, and 88 (35.4%) HRV-C. HRV-C infections were associated with asthma, recurrent wheezing, and bronchiolitis but were not significantly different from the HRV-A genogroup. Nevertheless, significant clinical differences were observed between the HRV-B genogroup and the other groups: more frequent infiltrate on chest radiograph (P = 0.017), fever (P = 0.052), diagnosis of pneumonia (P = 0.01), and antibiotic treatment (P = 0.004).

CONCLUSIONS

HRV-C infections were frequent in hospitalized children with respiratory diseases and were associated with asthma, recurrent wheezing, and bronchiolitis. No clinical differences were found with the HRV-A group: HRV-B group had clinical differences with both the other groups.

The ABCs of rhinoviruses, wheezing, and asthma

Human rhinoviruses (HRVs) were discovered as common cold pathogens over 50 years ago. Recent advances in molecular viral diagnostics have led to an appreciation of their role in more-significant respiratory illnesses, including bronchiolitis in infancy, childhood pneumonia, and acute exacerbations of chronic respiratory diseases such as asthma, chronic obstructive lung disease, and cystic fibrosis. Until a few years ago, only two groups of HRVs (A and B) had been recognized. However, full and partial sequencing of HRVs led to the discovery of a third species of HRV (HRV-C) that has distinct structural and biologic features. Risk factors and pathogenic mechanisms for more-severe HRV infections are being defined, and yet fundamental questions persist about mechanisms relating this common pathogen to allergic diseases and asthma. The close relationship between HRV infections and asthma suggests that antiviral treatments could have a major impact on the morbidity associated with this chronic respiratory disease.

The Back to School asthma study: the effect of montelukast on asthma burden when initiated prophylactically at the start of the school year

BACKGROUND

Pediatric asthma hospitalizations peak in early autumn.

OBJECTIVE

To determine the effectiveness of montelukast therapy in reducing the asthma burden in children when initiated prophylactically on school return.

METHODS

This was a randomized, multicenter, double-blind, placebo-controlled study of children with asthma aged 6 to 14 years. No minimum asthma symptoms were required, and patients could continue inhaled corticosteroid (ICS) use. Montelukast, 5 mg, chewable tablet (n = 580) or matching placebo (n = 582) was taken the night before the first day of school and nightly thereafter for 8 weeks. The primary end point was the percentage of days with worsening asthma, defined by one of the following: (1) increased beta-agonist use, (2) increased daytime symptoms, (3) awake "all night," (4) oral corticosteroid rescue or increased ICS use for worsening asthma, or (5) unanticipated health care utilization.

RESULTS

The reduction in the percentage of days with worsening asthma with montelukast use versus placebo use was not significant (24.3% vs 27.2%, P = .07). Prespecified subgroup analyses demonstrated nonsignificant trends favoring montelukast therapy in boys and older children but no effect by baseline ICS use or history of cold symptoms. Post hoc analysis showed a nonsignificant trend favoring montelukast therapy in reducing worsening asthma days for children commencing school after August 15 compared with earlier commencement.

CONCLUSIONS

Montelukast use was not significantly more effective than was placebo use in reducing the percentage of days with worsening asthma when initiated at the start of the school year. The effect of montelukast treatment on the fall peak in asthma burden may depend on sex, age, and the date of school return.

A probit- log- skew-normal mixture model for repeated measures data with excess zeros, with application to a cohort study of paediatric respiratory symptoms

BACKGROUND

A zero-inflated continuous outcome is characterized by occurrence of "excess" zeros that more than a single distribution can explain, with the positive observations forming a skewed distribution. Mixture models are employed for regression analysis of zero-inflated data. Moreover, for repeated measures zero-inflated data the clustering structure should also be modeled for an adequate analysis.

METHODS

Diary of Asthma and Viral Infections Study (DAVIS) was a one year (2004) cohort study conducted at McMaster University to monitor viral infection and respiratory symptoms in children aged 5-11 years with and without asthma. Respiratory symptoms were recorded daily using either an Internet or paper-based diary. Changes in symptoms were assessed by study staff and led to collection of nasal fluid specimens for virological testing. The study objectives included investigating the response of respiratory symptoms to respiratory viral infection in children with and without asthma over a one year period. Due to sparse data daily respiratory symptom scores were aggregated into weekly average scores. More than 70% of the weekly average scores were zero, with the positive scores forming a skewed distribution. We propose a random effects probit/log-skew-normal mixture model to analyze the DAVIS data. The model parameters were estimated using a maximum marginal likelihood approach. A simulation study was conducted to assess the performance of the proposed mixture model if the underlying distribution of the positive response is different from log-skew normal.

RESULTS

Viral infection status was highly significant in both probit and log-skew normal model components respectively. The probability of being symptom free was much lower for the week a child was viral positive relative to the week she/he was viral negative. The severity of the symptoms was also greater for the week a child was viral positive. The probability of being symptom free was smaller for asthmatics relative to non-asthmatics throughout the year, whereas there was no difference in the severity of the symptoms between the two groups.

CONCLUSIONS

A positive association was observed between viral infection status and both the probability of experiencing any respiratory symptoms, and their severity during the year. For DAVIS data the random effects probit -log skew normal model fits significantly better than the random effects probit -log normal model, endorsing our parametric choice for the model. The simulation study indicates that our proposed model seems to be robust to misspecification of the distribution of the positive skewed response.

Role of emerging respiratory viruses in children with severe acute wheezing

BACKGROUND

Acute wheezing episodes are frequently associated with respiratory viral infections in children. However, the role of the recently described respiratory viruses is not yet fully understood.

OBJECTIVE

The main objective of this study was to estimate the frequency of human metapneumovirus (HMPV), human bocavirus (HBoV), and 14 other respiratory viruses in hospitalized children with acute wheezing.

METHODS

A prospective study was conducted on children <14 years old, admitted with an acute expiratory wheezing episode from September 2005 to June 2008. Viruses were detected in nasopharyngeal aspirates by polymerase chain reaction. Clinical data were prospectively recorded.

RESULTS

A viral pathogen was identified in 444 (71%) out of 626 hospitalized acute wheezing episodes. Respiratory syncytial virus (RSV) was the most frequently detected (27%), followed by rhinovirus (24%), adenovirus (17.8%), HBoV (16%), and HMPV (4.7%). The rate of viral detection was significantly higher in infants (77.3%), than in older children (59.8%) (P < 0.001). RSV and HBoV were more prevalent in infants (P < 0.001) than in older children.

CONCLUSION

The most prevalent viruses found in severe acute wheezing episodes were RSV and rhinovirus not only in childhood, but also in infancy. However, other emerging viruses such as HBoV and metapneumovirus also play an important role in wheezing episodes.

Weekly monitoring of children with asthma for infections and illness during common cold seasons

Background

Exacerbations of childhood asthma and rhinovirus infections both peak during the spring and fall, suggesting that viral infections are major contributors to seasonal asthma morbidity.

Objectives

We sought to evaluate rhinovirus infections during peak seasons in children with asthma and to analyze relationships between viral infection and illness severity.

Methods

Fifty-eight children aged 6 to 8 years with asthma provided 5 consecutive weekly nasal lavage samples during September and April; symptoms, medication use, and peak flow were recorded. Rhinoviruses were identified by using multiplex PCR and partial sequencing of viral genomes.

Results

Viruses were detected in 36% to 50% of the specimens, and 72% to 99% of the viruses were rhinoviruses. There were 52 different strains (including 16 human rhinovirus C) among the 169 rhinovirus isolates; no strains were found in more than 2 collection periods, and all but 2 children had a respiratory tract infection. Virus-positive weeks were associated with greater cold and asthma symptom severity (P < .0001 and P = .0002, respectively). Furthermore, virus-positive illnesses had increased duration and severity of cold and asthma symptoms and more frequent loss of asthma control (47% vs 22%, P = .008). Although allergen-sensitized versus nonsensitized children had the same number of viral infections, the former had 47% more symptomatic viral illnesses (1.19 vs 0.81 per month, P = .03).

Conclusions

Rhinovirus infections are nearly universal in children with asthma during common cold seasons, likely because of a plethora of new strains appearing each season. Illnesses associated with viruses have greater duration and severity. Finally, atopic asthmatic children experienced more frequent and severe virus-induced illnesses.

Asthma: clinical expression and molecular mechanisms

Asthma is a complex disorder that displays heterogeneity and variability in its clinical expression both acutely and chronically. This heterogeneity is influenced by multiple factors including age, sex, socioeconomic status, race and/or ethnicity, and gene by environment interactions. Presently, no precise physiologic, immunologic, or histologic characteristics can be used to definitively make a diagnosis of asthma, and therefore the diagnosis is often made on a clinical basis related to symptom patterns (airways obstruction and hyperresponsiveness) and responses to therapy (partial or complete reversibility) over time. Although current treatment modalities are capable of producing control of symptoms and improvements in pulmonary function in the majority of patients, acute and often severe exacerbations still occur and contribute significantly to both the morbidity and mortality of asthma in all age groups. This review will highlight some of the important clinical features of asthma and emphasize recent advances in both pathophysiology and treatment.

Dispensing of fluticasone propionate/salmeterol combination in the summer and asthma-related outcomes in the fall

BACKGROUND

Asthma exacerbations occur year-round; however, peak asthma-related events occur in the fall and are frequently associated with viral respiratory infections.

OBJECTIVE

To compare the rates of asthma-related emergency department (ED) visits and hospitalizations in the fall (September, October, November) between users and nonusers of fluticasone propionate plus salmeterol in a single inhaler (FSC) in the preceding summer.

METHODS

This was a retrospective, observational study using health care claims from a large managed care database. Patients age 4 to 55 years with both a medical claim for asthma and a pharmacy claim for FSC were categorized into 3 age groups: children (4-11 years), adolescents (12-18 years), and adults (19-55 years).

RESULTS

There were 201,973 observations of FSC dispensings and 184,143 observations without FSC. Across all age groups, summertime dispensings of FSC were associated with a significantly lower (P < .001) risk of an asthma-related ED visit (4-11 years: adjusted odds ratio [OR], 0.54, 95% CI, 0.49-0.60; 12-18 years: OR, 0.59, 95% CI, 0.54-0.64; 19-55 years: OR, 0.53, 95% CI, 0.51-0.55) or hospitalization (4-11 years: OR, 0.43, 95% CI, 0.35-0.54; 12-18 years: OR, 0.49, 95% CI, 0.40-0.60; 19-55 years: OR, 0.61, 95% CI, 0.57-0.65) in the subsequent fall. This protective effect persisted even for patients with fall dispensings of FSC. The risk of oral corticosteroid dispensing in the fall was also significantly reduced in all age groups.

CONCLUSION

Summertime dispensings of FSC were associated with a decreased risk of serious asthma-related outcomes in the subsequent fall. Continuous use of FSC before seasonal viral exposure may decrease seasonally related exacerbations.

The role of budesonide/formoterol for maintenance and relief in the management of asthma

The aim of asthma management is to gain and maintain asthma control and reduce the risk of future exacerbations. However, despite the availability of effective therapies and national and international guidelines for their use, many patients remain inadequately controlled and continue to endure and accept a reduced quality of life. This review discusses current challenges in asthma management facing primary care physicians and provides insight into new treatment strategies developed to improve asthma control. A web-based literature review was undertaken with a focus on studies and reviews discussing asthma control and management with traditional therapies and new therapies, including a novel treatment approach using budesonide/formoterol maintenance and reliever therapy. One of the most common problems in long-term asthma control is poor adherence to inhaled corticosteroid (ICS) maintenance therapy, resulting in under-treatment of inflammation. Many patients tend to over-rely on short-acting beta(2)-agonist medication for quick relief of symptoms at the expense of ICS therapy, thus lowering anti-inflammatory protection and increasing the propensity for the development of severe and potentially life-threatening exacerbations. New simplified treatment strategies have been investigated with the aim of overcoming many of these primary care challenges, ultimately improving asthma control and reducing the future risk of exacerbations.

Oxymetazoline inhibits and resolves inflammatory reactions in human neutrophils

The nasal decongestant oxymetazoline (OMZ) exhibits anti-oxidative and anti-inflammatory properties (I. Beck-Speier et al., J Pharmacol Exp Ther. 2006;316:842-851). In a follow up study, we hypothesized that OMZ generates pro-resolving lipoxins being paralleled by production of immune-modulating prostaglandin E(2) (PGE(2)) and anti-inflammatory 15(S)-hydroxy-eicosatetraenoic acid [15(S)-HETE] and depletion of pro-inflammatory leukotriene B(4) (LTB(4)). Human neutrophils (PMN) were chosen as the cellular system. The effect of OMZ on these parameters as well as on respiratory burst activity and oxidative stress marker 8-isprostane was analyzed in unstimulated and co-stimulated PMN by ultrafine carbon particles (UCP) or opsonized zymosan (OZ), respectively. In unstimulated cells, OMZ induced formation of PGE(2), 15(S)-HETE, and LXA(4). The levels of LTB(4) and 8-isoprostane were not affected, whereas respiratory burst activity was drastically inhibited. In UCP- and OZ-stimulated control cells, all parameters were elevated. Here, OMZ maintained the increased levels of PGE(2), 15(S)-HETE, and LXA(4), but substantially suppressed levels of LTB(4) and 8-isoprostane and inhibited the respiratory burst activity. These findings suggest a switch from the pro-inflammatory eicosanoid class LTB(4) to the pro-resolving LXA(4). Since LXA(4) is most relevant in returning inflamed tissue to homeostasis, OMZ is postulated to terminate rhinitis-related inflammation, thus contributing to shortening of disease duration.

Ipratropium bromide for acute asthma exacerbations in the emergency setting: a literature review of the evidence

Since the 1970s, when inhaled anticholinergic agents were first introduced as adjunct therapies for the immediate treatment of pediatric asthma exacerbations, several trials have shown varying degrees of benefit from their use as bronchodilators in combination with inhaled short-acting beta-adrenergic agonists and systemic corticosteroids. Although other anticholinergics exist, ipratropium bromide (IB) specifically has emerged as the overwhelming choice of pulmonologists and emergency physicians because of its limited systemic absorption from the lungs when given as an inhaled preparation. However, although the varying trials, predominantly in the emergency department setting, have typically shown a trend toward improved outcomes, none has set forth clear dosing protocol recommendations for use by practicing physicians. It is our goal in this review of the available literature on the use of IB, as an adjunct to inhaled short-acting beta-adrenergic agonists, to summarize practical, evidence-based recommendations for use in the pediatric emergency department setting for acute asthma exacerbations. We also hope to better delineate the most effective dosing regimen in those patients who might benefit most from the addition of IB and to explore proposed additional benefits it may have as a modulator of cholinergic-induced effects from high-dose beta-agonist therapy and viral triggers.

The September epidemic of asthma in Israel

BACKGROUND

The seasonality of asthma morbidity is well recognized. A peak in asthma exacerbations in September has been noted for years at our center.

OBJECTIVE

To examine the hypothesis that the increment in asthma exacerbations in September is influenced by the beginning of the kindergarten and school year.

METHODS

The monthly admission rate for asthma in patients of different ages was retrospectively evaluated in seven hospitals from various areas in Israel from January 2003 to December 2005.

RESULTS

Of the 408,242 hospital admissions during the study period, 8,011 were for asthma exacerbations: 4,091 in adults (1.3% of adult admissions) and 3,920 in children (3.8% of pediatric admissions). The asthma admission rates varied considerably throughout the year, with a peak of 4% of total admissions in the winter months and a nadir of 2% in the summer months. September was unique for its particularly high rate of admissions for asthma attacks in children (6% of total admissions), especially toddlers and the school-age group. In adults there was a progressive increase in asthma admissions from September through December without a unique peak in September.

CONCLUSIONS

There is a characteristic increase in asthma exacerbations and admissions in September in the pediatric age group. This phenomenon might be explained by the increased exposure to respiratory viruses, to new allergen exposure in school or kindergarten, increased emotional stress due to start of the new school year, or poor compliance and withdrawal of treatment during the summer. Clinicians should consider administering prophylactic treatment for asthma in children before onset of the school year.

Rhinovirus-induced exacerbations of asthma: How is the {beta}2-adrenoceptor implicated?

Rhinovirus (RV) infections are the major cause of asthma exacerbations in children and adults. Under normal circumstances, asthmatic airway obstruction improves spontaneously or characteristically briskly in response to inhaled beta(2)-adrenergic receptor (beta(2)AR) agonists. During virus-associated exacerbations, an impaired response to beta(2)AR agonists is observed; the reason for this is not known. The objective of this study was to determine the effect of RV infection on airway smooth muscle beta(2)AR function. The human cell line Beas-2B and primary human bronchial epithelial cells (HBECs) were infected with RV (multiplicity of infection = 1). After 1 or 5 days for primary and Beas-2B cells, respectively, cell culture supernatants were harvested, UV-irradiated to inactivate RV, and applied to human airway smooth muscle cells for 3 days to assess modifications of beta(2)AR function. RV conditioned medium from Beas-2B and HBECs decreased beta(2)AR agonist-induced cAMP by 50 and 65%, respectively (n = 5; P < 0.05). When cAMP was induced independently of the beta(2)AR using forskolin, no impairment was found. Using flow cytometry, we demonstrated that this decrease was likely the result of beta(2)AR desensitization because membrane but not total cell receptor beta(2)AR was decreased. Pretreatment of HBECs and Beas-2B cells but not human airway smooth muscle cells with the corticosteroids dexamethasone or fluticasone abolished virus-mediated beta(2)AR loss of function. This study shows that epithelial infection with RV induces a decrease of beta(2)AR function on airway smooth muscle cells, potentially explaining the clinical observation of loss of beta(2)AR agonist function during RV-induced asthma exacerbations.

Human rhinovirus C associated with wheezing in hospitalised children in the Middle East

BACKGROUND

Few studies have investigated the disease burden and genetic diversity of human rhinoviruses (HRVs) in developing countries.

OBJECTIVES

To assess the burden of HRV in Amman, Jordan, and to characterise clinical differences between HRV groups.

STUDY DESIGN

We prospectively studied children <5 years, hospitalised with respiratory symptoms and/or fever in Amman, Jordan. Viruses were identified by real-time reverse transcriptase polymerase chain reaction (RT-PCR). VP4/VP2 gene sequencing was performed on HRV-positive specimens.

RESULTS

Of the 728 enrolled children, 266 (37%) tested positive for picornaviruses, 240 of which were HRV. Of the HRV-positive samples, 62 (26%) were of the recently identified group HRVC, 131 (55%) were HRVA and seven (3%) were HRVB. The HRVC strains clustered into at least 19 distinct genotypes. Compared with HRVA-infected children, children with HRVC were more likely to require supplemental oxygen (63% vs. 42%, p=0.007) and, when co-infections were excluded, were more likely to have wheezing (100% vs. 82%, p=0.016).

CONCLUSIONS

There is a significant burden of HRV-associated hospitalisations in young children in Jordan. Infection with the recently identified group HRVC is associated with wheezing and more severe illness.

Higher serum folate levels are associated with a lower risk of atopy and wheeze

BACKGROUND

Folic acid is known to be associated with inflammatory diseases, but the relationship between folic acid and allergic diseases is unclear.

OBJECTIVES

The purpose of the study was to examine the relationship between serum folate levels and markers of atopy, wheeze, and asthma.

METHODS

Data were obtained from the 2005-2006 National Health and Nutrition Examination Survey in which serum folate and total IgE levels were measured in 8083 subjects 2 years of age and older. A high total IgE level was defined as greater than 100 kU/L. Allergen-specific IgE levels were measured for a panel of 5 common aeroallergens. Atopy was defined as at least 1 positive allergen-specific IgE level. Doctor-diagnosed asthma and wheeze in the previous 12 months were assessed by means of questionnaire.

RESULTS

Serum folate levels were inversely associated with total IgE levels (P < .001). The odds of a high total IgE level, atopy, and wheeze decreased across quintiles of serum folate levels, indicating a dose-response relationship between serum folate levels and these outcomes. Each of these associations remained statistically significant after adjusting for age, sex, race/ethnicity, and poverty index ratio. Adjusted odds ratios associated with the fifth quintile of folate relative to the first quintile were as follows: high IgE level, 0.70 (95% CI, 0.53-0.92); atopy, 0.69 (95% CI, 0.57-0.85); and wheeze, 0.60 (95% CI, 0.44-0.82). Higher folate levels were also associated with a lower risk of doctor-diagnosed asthma, but this finding was not statistically significant (odds ratio for fifth quintile vs first quintile, 0.84 [95% CI, 0.70-1.02]).

CONCLUSIONS

Serum folate levels are inversely associated with high total IgE levels, atopy, and wheeze.

Seasonal patterns in health care use and pharmaceutical claims for asthma prescriptions for preschool- and school-aged children

BACKGROUND

In children, hospitalization for asthma is reported to have a distinct seasonal pattern with peaks coincident with the start of school. Although guidelines indicate that asthma controller medications should be used daily, there is limited information on actual seasonal patterns of medication use.

OBJECTIVE

To describe seasonal patterns of asthma-related health care use and asthma controller and reliever medication claims in children.

METHODS

An ecological analysis was conducted of data collected from records for children aged 2 to 12 years from 2002 through 2004 from an automated research database of insurance claims from a large US health care plan. Seasonal patterns for health care use and estimates of prescription asthma controller and reliever use were determined for preschool-aged children (aged 2-5 years) and school-aged children (aged 6-12 years). Rates were constructed by week; deviations from annual mean rates were used to determine peaks in use. Results were confirmed using Poisson regression models, modeling for rates within age group, with factors for week, year, and regions.

RESULTS

Emergency department and outpatient visits and hospitalizations were lowest during summer; rates increased beginning in September, peaking in October or November. Asthma controller and reliever medication claims increased beginning in September, peaking in December. Rates also were elevated in February.

CONCLUSIONS

The data suggest that children who reduce their asthma medications during the summer do not resume taking medications until signs or symptoms of asthma worsen. The summer hiatus and other factors may contribute to seasonal increases in health care use and in asthma medication prescriptions, particularly in the fall.

A novel group of rhinoviruses is associated with asthma hospitalizations

BACKGROUND

Although recent studies have identified new group C human rhinoviruses (HRVCs), their spectrum of pediatric disease is unknown.

OBJECTIVE

We sought to determine the presentation and burden of disease caused by HRVCs among young hospitalized children.

METHODS

We conducted prospective population-based surveillance in 2 US counties among children less than 5 years of age hospitalized with acute respiratory illness or fever from October 2001 through September 2003. Nasal/throat swabs were obtained and tested for HRVs, as determined by means of RT-PCR and then characterized by means of partial sequencing.

RESULTS

Of 1052 children enrolled and tested during the 2-year period, 167 (16%) had HRVs detected. Of 147 samples successfully sequenced, 64 were group A HRVs, 6 were group B HRVs, and 77 were HRVCs. Children with HRVCs were significantly more likely than those with group A HRVs to have underlying high-risk conditions, such as asthma (42% vs 23%, P = .023) and to have had a discharge diagnosis of asthma (55% vs 36%, P = .022).

CONCLUSIONS

Overall, HRVCs were detected in 7% of children hospitalized for fever or respiratory conditions and constituted almost half of all rhinovirus-associated hospitalizations, suggesting that this novel group causes a substantial burden of pediatric disease.

Epidemiology

The common cold is the result of an upper respiratory tract infection causing an acute syndrome characterised by a combination of non-specific symptoms, including sore throat, cough, fever, rhinorrhoea, malaise, headache, and myalgia. Respiratory viruses, alone or in combination, are the most common cause. The course f illness can be complicated by bacterial agents, causing pharyngitis or sinusitis, but the are a rare cause of cold and flu-like illnesses (CFLIs). Our understanding of CFLI epidemiology has been enhanced by molecular detection methods, particularly polymerase chain reaction (PCR) testing. PCR has not only improved detection of previously known viruses, but within the last decade has resulted in the detection of many divergent novel respiratory virus species. Human rhinovirus (HRV) infections cause nearly all CFLIs and they can be responsible for asthma and chronic obstructive pulmonary disease exacerbations. HRVs are co-detected with other respiratory viruses in statistically significant patterns, with HRVs occurring in the lowest proportion of co-detections, compared to most other respiratory viruses. Some recently identified rhinoviruses may populate an entirely new putative HRV species; HRV C. Further work is required to confirm a causal role for these newly identified viruses in CFLIs. The burden of illness associated with CFLIs is poorly documented, but where data are available, the impact of CFLIs is considerable. Individual infections, although they do not commonly result in more severe respiratory tract illness, are associated with substantial direct and indirect resource use. The product of frequency and burden for CFLIs is likely to be greater in magnitude than for any other respiratory syndrome, but further work is required to document this. Our understanding of the viral causes of CLFIs, although incomplete, has improved in recent years. Documenting burden is also an important step in progress towards improved control and management of these illnesses.

Pediatric asthma and related allergic and nonallergic diseases: patient-oriented evidence-based essentials that matter

Asthma is the most common medical diagnosis among hospitalized children. In the USA, asthma has accounted for approximately 15% of nonsurgical admissions to hospital in the pediatric age group. Asthma is also one of the leading causes for emergency care requirements, one of the leading causes for missed school, and a cause for considerable morbidity, disability and occasional mortality at all ages. Despite these discouraging statistics, convincing data indicate that this failure of asthma management is not the result of inadequate therapeutic potential, but instead represents ineffective delivery of medical care. Management of asthma and its major co-morbidities, allergic and nonallergic rhinitis, and atopic dermatitis requires a knowledge of the alternative therapies, natural history, and educational techniques for providing patients and families with the ability to manage these troublesome chronic disorders.