Correlates of recurrent wheezing in school-age children. The Physicians of Raleigh Pediatric Associates

A Qualitative Study of Unfairness and Distrust in Smoke-free Housing

Objectives: Whereas smoke-free housing (SFH) has the potential to protect residents from tobacco smoke, evidence suggests that SFH could lead to increased indoor smoking. In this study, we examine how perceptions of a residential smoking ban could be related to non-compliance. Methods: We conducted 8 focus group interviews of low-income housing residents living in Norfolk, Virginia (N=53). Interviews were semi-structured and based on a list of guided questions related to SFH compliance, developed in partnership with a standing community advisory board comprised of low-income housing residents. Results: Several themes emerged, including pervasive non-compliance, perceived unfairness and shame, barriers to compliance, and distrust of the housing authority. Smokers reported behavior primarily motivated by punishment avoidance, rather than out of any perceived obligation to comply with the ban. Conclusions: Results led us to consider Procedural Justice Theory as a conceptual framework, in which compliance is directly related to perceptions about the legitimacy of a rule or authority. When compliance is low due to a lack of perceived legitimacy, SFH should be adapted to promote changes in smoking behavior. We offer specific theory-supported adaptations to SFH focused on trust-building and improving perceived fairness.

Pyruvate kinase M2 in lung APCs regulates Alternaria-induced airway inflammation

Sensitivity to allergenic fungi (Alternaria alternata) is associated with acute, severe asthma attacks. Antigen presenting cells (APCs) in the lung sense environmental perturbations that induce cellular stress and metabolic changes and are critical for allergic airway inflammation. However, the mechanisms underlying such environmental sensing by APCs in the lung remains unclear. Here we show that acute Alternaria challenge rapidly induces neutrophil accumulation in airways, and alter expressions of Pyruvate Kinase (PKM2) and hypoxia-inducible factor -1α (Hif-1α) that correlates with proinflammatory mediator release. Blockade of IL33 signaling in vivo led to reduce oxidative stress and glycolysis in lung APCs. Lung-specific ablation of CD11c+ cells abrogates Alternaria-induced neutrophil accumulation and inflammation. Furthermore, administration of Alternaria into the airways stimulated APCs and elevate the expression of Glut-1. Mechanistically, we establish that PKM2 is a critical modulator of lung APC activation in Alternaria-induced acute inflammation. Allosteric activation of PKM2 by a small molecule ML265 or siRNA-mediated knock down correlated negatively with glycolysis and activation of APCs. These results collectively demonstrates that PKM2-mediated glycolytic reprogramming by fungal allergen Alternaria influences lung APC activation, thereby promotes acute airway inflammation. Our data support a model in which Alternaria sensitization in airways induce a circuitry of glycolysis and PKM2 regulation that confers an acute activation of APCs in the lung, whose targeting might represent a strategy for asthma treatment.

Impact of perinatal environmental tobacco smoke on the development of childhood allergic diseases

Allergic diseases such as asthma, allergic rhinitis, atopic dermatitis, and food allergy, are most common chronic, noncommunicable diseases in childhood. In the past few decades, the prevalence has increased abruptly worldwide. There are 2 possible explanations for the rising prevalence of allergic diseases worldwide, that an increased disease-awareness of physician, patient, or caregivers, and an abrupt exposure to unknown hazards. Unfortunately, the underlying mechanisms remain largely unknown. Despite the continuing efforts worldwide, the etiologies and rising prevalence remain unclear. Thus, it is important to identify and control risk factors in the susceptible individual for the best prevention and management. Genetic susceptibility or environments may be a potential background for the development of allergic disease, however they alone cannot explain the rising prevalence worldwide. There is growing evidence that epigenetic change depends on the gene, environment, and their interactions, may induce a long-lasting altered gene expression and the consequent development of allergic diseases. In epigenetic mechanisms, environmental tobacco smoke (ETS) exposure during critical period (i.e., during pregnancy and early life) are considered as a potential cause of the development of childhood allergic diseases. However, the causal relationship is still unclear. This review aimed to highlight the impact of ETS exposure during the perinatal period on the development of childhood allergic diseases and to propose a future research direction.

Environmental tobacco smoke exposure and risk of allergic sensitisation in children: a systematic review and meta-analysis

BACKGROUND

Environmental tobacco smoke (ETS) exposure in children is linked with the development of allergic asthma. However, its influence on allergic sensitisation in children has not been conclusively determined.

OBJECTIVE

To systematically review existing evidence of ETS exposure's impact on markers of allergic sensitisation in children.

METHODS

CENTRAL, MEDLINE and EMBASE databases were searched. Included studies assessed following markers of atopic sensitisation: total immunoglobulin E (tIgE) concentrations, at least one specific IgE (sIgE+), and positive skin-prick tests (SPTs+) in ETS-exposed and non-exposed children.

RESULTS

8 studies on the influence of ETS on tIgE concentration (2603 patients), 6 studies on ETS and sIgE+ (9230 participants) and 14 papers on ETS and SPT (14 150 patients) met our inclusion criteria. ETS was shown to raise tIgE concentrations by 27.7 IU/mL (95% CI 7.8 to 47.7; I(2)=58%; results based on 3 studies) and to increase the risk of atopic sensitisation, as assessed by sIgE+ (OR=1.12, 95%CI 1.00 to 1.25; I(2)=54%; results based on 4 studies) and SPT+ (OR=1.15; 95% CI 1.04 to 1.28; I(2)=0%; results based on 10 studies). In a subgroup analysis, this effect was most pronounced in children <7 years (preschoolers) by OR=1.20; (95% CI 1.05 to 1.38) and OR=1.30 (95% CI 1.05 to 1.61), (for sIgE+ and SPT+, respectively).

CONCLUSIONS

Current analysis supports an association between ETS exposure in early childhood and the increased risk of allergic sensitisation. Subgroup meta-analyses demonstrate that younger children suffer the most from detrimental immunomodulating effects of ETS exposure. This study underscores ETS as an important but avoidable risk factor for the development of allergic disease in children.

Interleukin-13 genetic variants, household carpet use and childhood asthma

Interleukin (IL)-13 genetic polymorphisms have shown adverse effects on respiratory health. However, few studies have explored the interactive effects between IL-13 haplotypes and environmental exposures on childhood asthma. The aims of our study are to evaluate the effects of IL-13 genetic variants on asthma phenotypes, and explore the potential interaction between IL-13 and household environmental exposures among Taiwanese children. We investigated 3,577 children in the Taiwan Children Health Study from 14 Taiwanese communities. Data regarding children's exposure and disease status were obtained from parents using a structured questionnaire. Four SNPs were tagged accounting for 100% of the variations in IL-13. Multiple logistic regression models with false-discovery rate (FDR) adjustments were fitted to estimate the effects of IL-13 variants on asthma phenotypes. SNP rs1800925, SNP rs20541 and SNP rs848 were significantly associated with increased risks on childhood wheeze with FDR of 0.03, 0.04 and 0.04, respectively. Children carrying two copies of h1011 haplotype showed increased susceptibility to wheeze. Compared to those without carpet use and h1011 haplotype, children carrying h1011 haplotype and using carpet at home had significantly synergistic risks of wheeze (OR, 2.5; 95% CI, 1.4–4.4; p for interaction, 0.01) and late-onset asthma (OR, 4.7; 95% CI, 2.0–10.9; p for interaction, 0.02). In conclusions, IL-13 genetic variants showed significant adverse effects on asthma phenotypes among children. The results also suggested that asthma pathogenesis might be mediated by household carpet use.

A PDA-based Network for Telemonitoring Asthma Triggering Gases in the El Paso School Districts of the US - Mexico Border Region

In this paper we describe the application of a personal digital assistant (PDA) or pocket PC as an effective communication device to telemonitor levels of asthma triggering gases collected from a remote location under test to a workstation which has a personal computer (PC) running on Windows XP&#174; as the operating system. The Bluetooth&#174; features of the PDA are explored to transmit data collected by a Direct&#8482; Sense Tox toxic gas monitor equipped with five toxic gas probes and one temperature sensor in real time, thereby making this telemonitoring system an innovative instrument in monitoring levels of asthma triggering gases in the El Paso-border metropolitan region, a region in which asthma is highly prevalent especially in children. At the workstation or fixed location these readings are displayed using a custom made, user friendly graphical user interface (GUI) developed using software tools like action scripting with Macromedia&#174; Flash&#8482;. The growing advancement in technology and ever diminishing sizes of handheld devices encouraged us to opt for this configuration. Moreover, the PDA and toxic gas monitor were also chosen for their light weight, portability, flexibility, low cost and data collection and transmission capabilities.

Household smoking behavior: effects on indoor air quality and health of urban children with asthma

The goal of the study was to examine the association between biomarkers and environmental measures of second hand smoke (SHS) with caregiver, i.e. parent or legal guardian, report of household smoking behavior and morbidity measures among children with asthma. Baseline data were drawn from a longitudinal intervention for 126 inner city children with asthma, residing with a smoker. Most children met criteria for moderate to severe persistent asthma (63%) versus mild intermittent (20%) or mild persistent (17%). Household smoking behavior and asthma morbidity were compared with child urine cotinine and indoor measures of air quality including fine particulate matter (PM(2.5)) and air nicotine (AN). Kruskal-Wallis, Wilcoxon rank-sum and Spearman rho correlation tests were used to determine the level of association between biomarkers of SHS exposure and household smoking behavior and asthma morbidity. Most children had uncontrolled asthma (62%). The primary household smoker was the child's caregiver (86/126, 68%) of which 66 (77%) were the child's mother. Significantly higher mean PM(2.5), AN and cotinine concentrations were detected in households where the caregiver was the smoker (caregiver smoker: PM(2.5) μg/m(3): 44.16, AN: 1.79 μg/m(3), cotinine: 27.39 ng/ml; caregiver non-smoker: PM(2.5): 28.88 μg/m(3), AN: 0.71 μg/m(3), cotinine:10.78 ng/ml, all P ≤ 0.01). Urine cotinine concentrations trended higher in children who reported 5 or more symptom days within the past 2 weeks (>5 days/past 2 weeks, cotinine: 28.1 ng/ml vs. <5 days/past 2 weeks, cotinine: 16.2 ng/ml; P = 0.08). However, environmental measures of SHS exposures were not associated with asthma symptoms. Urban children with persistent asthma, residing with a smoker are exposed to high levels of SHS predominantly from their primary caregiver. Because cotinine was more strongly associated with asthma symptoms than environmental measures of SHS exposure and is independent of the site of exposure, it remains the gold standard for SHS exposure assessment in children with asthma.

Factors associated with second-hand smoke exposure in young inner-city children with asthma

OBJECTIVES

To examine the association of social and environmental factors with levels of second-hand smoke (SHS) exposure, as measured by salivary cotinine, in young inner-city children with asthma.

METHODS

We used data drawn from a home-based behavioral intervention for young high-risk children with persistent asthma post-emergency department (ED) treatment (N = 198). SHS exposure was measured by salivary cotinine and caregiver reports. Caregiver demographic and psychological functioning, household smoking behavior, and asthma morbidity were compared with child cotinine concentrations. Chi-square and ANOVA tests and multivariate regression models were used to determine the association of cotinine concentrations with household smoking behavior and asthma morbidity.

RESULTS

Over half (53%) of the children had cotinine levels compatible with SHS exposure and mean cotinine concentrations were high at 2.42 ng/ml (SD 3.2). The caregiver was the predominant smoker in the home (57%) and 63% reported a total home smoking ban. Preschool aged children and those with caregivers reporting depressive symptoms and high stress had higher cotinine concentrations than their counterparts. Among children living in a home with a total home smoking ban, younger children had significantly higher mean cotinine concentrations than older children (cotinine: 3-5 year olds, 2.24 ng/ml (SD 3.5); 6-10 year olds, 0.63 ng/ml (SD 1.0); p < .05). In multivariate models, the factors most strongly associated with high child cotinine concentrations were increased number of household smokers (β = 0.24) and younger child age (3-5 years) (β = 0.23; p < .001, R(2) = 0.35).

CONCLUSION

Over half of the young inner-city children with asthma were exposed to SHS, and caregivers are the predominant household smokers. Younger children and children with depressed and stressed caregivers are at significant risk of smoke exposures, even when a household smoking ban is reported. Further advocacy for these high-risk children is needed to help caregivers quit and to mitigate smoke exposure.

Clinical characteristics according to sensitized allergens in adult korean patients with bronchial asthma

Purpose

Allergic sensitization is a risk factor for the development of bronchial asthma. This study was conducted to investigate clinical manifestations according to sensitized allergens in adult Korean patients with bronchial asthma.

Methods

In total, 523 adult patients who were diagnosed with bronchial asthma between March 2002 and March 2008 were included in the study. All patients underwent skin prick tests for approximately 45 allergens or a specific IgE test. Sensitized allergens were grouped into the following categories: house dust mites, fungus, pollen, and animal dander. Atopy was defined as a positive skin prick test response or the presence of a specific IgE to one or more allergens.

Results

Of the 523 patients, 295 (56%) were sensitized to one or more allergens. A younger median age, greater proportion of males, higher eosinophil counts, and higher total IgE levels were observed in the atopic asthma group compared to the non-atopic asthma group. The PC20 value was negatively correlated with eosinophil counts and total IgE in the atopic asthma group. In the subgroup analysis, patients sensitized to Cladosporium showed poorer pulmonary function and a higher response to bronchodilators. In addition, patients sensitized to Alternaria showed severer bronchial hyperresponsiveness than non-atopic patients with asthma. Finally, a gradual increase in the number of sensitized allergens was noted with increasing age, eosinophil counts, and total IgE levels.

Conclusions

We suggest the need for identifying the existence of atopy and exact offending allergens at the time of asthma diagnosis, since significant differences in sex, age, blood test results, and lung function were observed according to atopy and sensitized allergens.

Effects of a DNA vaccine in an animal model of Alternaria alternata sensitivity

Sensitivity to the fungus Alternaria is associated with asthma persistence and severity. Current therapeutic options for treating Alternaria-induced airway inflammation are limited. In this study, Brown Norway rats are used to study the effectiveness of a DNA-based vaccine delivered to the airway in attenuating the response to a major Alternaria allergen, rAlt a 2. Compared to untreated sensitized animals, or animals receiving an "out-of-frame" DNA-based vaccine, animals treated with "in-frame" DNA vaccine showed an attenuation in specific IgE antibody titers to rAlt a 2, an increase in IgG(2b) (a Th1 response), a reduction in spontaneous IL-13 release by peribronchial lymph node cell suspensions, and an attenuation in the decrease in total lung capacity 72 h post-allergen challenge. Further, histopathologic examination of the lung tissues revealed reduced pulmonary inflammation post-allergen challenge in the DNA-vaccine-treated compared to sensitized, untreated animals. We conclude that a DNA-based vaccine delivered to the airway significantly influences the immunologic, pulmonary physiologic, and histological alterations induced by challenge with a major Alternaria allergen, rAlt a 2, in sensitized animals.

Alternaria measures in inner-city, low-income housing by immunoassay and culture-based analysis

BACKGROUND

Sensitivity to Alternaria allergens has been associated with severe asthma and life-threatening exacerbations, and a high prevalence of Alternaria sensitivity has been reported among inner-city populations. Traditionally, epidemiologic studies have measured indoor Alternaria concentrations by cultural analyses; however, the number of viable spores may not be a good proxy for allergen levels. Furthermore, other genera share epitopes with Alternaria that may contribute to the allergenic effect.

OBJECTIVE

To compare measures of Alternaria antigen by enzyme-linked immunosorbent assay with measures of Alternaria and cross-reactive genera (Ulocladium, Curvularia, Epicoccum, and Stemphylium) by cultural analysis.

METHOD

Antigen assays and cultural analyses were performed on vacuum-collected bed dust samples collected between June 18, 2002, and February 9, 2004, from 3 inner-city, low-income public housing developments.

RESULTS

Alternaria antigen was found in all bed dust samples regardless of season. However, culturable Alternaria, Ulocladium, Curvularia, Epicoccum, and Stemphylium were only found in 50%, 35%, 6%, 11%, and 0% of bed samples, respectively. No correlations were found between Alternaria antigen and culturable concentrations of Alternaria or of its cross-reactive genera except for marginal correlation with Ulocladium culturable concentrations.

CONCLUSIONS

The results confirm that exposure to Alternaria antigens and allergens can occur even in the absence of culturable Alternaria or its cross-reactive genera, so further refinement and use of assays are essential for characterizing the distribution and determinants of indoor fungal allergen levels forsensitive populations.

Housing conditions and respiratory health in a Boston public housing community

OBJECTIVES

To determine frequency of and possible associations between environmental housing factors and self-reported respiratory symptoms in public housing.

METHODS

We used a community-participatory method in which trained residents conducted in-person interviews with a random sample of 53 households in one housing development in Boston, Massachusetts.

RESULTS

Environmental factors suspected of affecting respiratory health that were reported by more than 30 percent of respondents included: Moisture (43 percent), mold (43 percent), cracks in walls, floors and ceilings (49 percent), sewage leaks (33 percent), unexplained odor (35 percent), use of air fresheners (91 percent), use of gas ovens for heating (38 percent), no vent for the oven (74 percent), stuffy air (66 percent), overheating at least part of the winter (73 percent), cockroaches (70 percent), rodents (40 percent), pets (39 percent), frequent renovations (40 percent), repeated requests for repairs (52 percent), dust from construction (45 percent), use of more than three hazardous household products (32 percent), vehicle traffic nearby (81 percent), and smoking in the household (57 percent). Forty percent of respondents reported having asthma. Respondents also reported that 56 percent of their children had asthma. Forty percent of respondents reported wheeze and 48 percent reported coughing or sneezing episodes in the preceding month. We found the following positive statistically significant associations, adjusted for age, sex, Black or Hispanic origin, and years lived in public housing: wheeze with moisture problems (OR = 4.8; CI = 1.2, 19.3), sewage leaks (OR = 6.3; CI = 1.3, 30.3), odor (OR = 7.5; CI = 1 .4, 39.0), cracks in walls,floors and ceilings (OR = 8.6; CI 1.9, 38.0), and frequency of renovations (OR = 9.8; CI = 1.8, 54.4); cough with moisture problems (OR = 5.3; CI = 1.3, 20.8), stuffy air (OR = 4.4; CI = 1.2, 16.7), cockroaches (OR = 5.4; CI = 1.2, 24.2), smoking (OR = 5.0; CI = 1.2, 20.5), odor (OR = 10.9; CI = 2.3, 53.0), cracks in walls, floors and ceilings (OR = 6.2; CI = 1.8, 22.3) and frequency of renovations (OR = 4.4; CI = 1.1, 17.5); and sneeze with cockroaches (OR = 5.2; CI = 1.1, 24.2), stuffy air (OR = 6.3; CI = 1.5, 26.5), cracks in walls, floors and ceilings (OR = 6.3; CI = 1.7, 23.1), repeated requests for repairs (OR = 5.6; CI = 1.4, 21.5), and construction dust (OR = 15.6; CI = 2.2, 112.3).

CONCLUSIONS

Housing conditions that affect respiratory health were common in this public housing development. Self-reported rates of respiratory symptoms and asthma were extremely high. Statistical associations between housing conditions and respiratory symptoms in the preceding month were frequently positive and sometimes statistically significant. Engaging community residents strengthened the research process.

Health effects of indoor nitrogen dioxide and passive smoking on urban asthmatic children

BACKGROUND

Nitrogen dioxide (NO(2)) and environmental tobacco smoke (ETS) have been associated with adverse respiratory effects.

OBJECTIVE

We sought to assess the effect of NO(2) and ETS on asthma morbidity among children in inner-city environments.

METHODS

Asthmatic children between the ages of 4 and 9 years had exposure to NO(2) and ETS measured by using Palmes tubes in the home and urinary cotinine. A baseline interview and telephone assessments at 3, 6, and 9 months evaluated health service use, asthma symptoms, and peak flow rates.

RESULTS

Gas stoves were present in 87.8% of 469 homes. The median level of indoor NO(2) was 29.8 ppb compared with the US national outdoor median of 18 ppb. Of 1444 children, 48% had urinary cotinine/creatinine ratios of greater than 30 ng/mg. The median level of the cotinine/creatinine ratio was 42.4 ng/mg in smoking homes compared with 18.0 ng/mg in nonsmoking homes. The relative risk for asthma symptoms with increased NO(2) exposure was 1.75 (95% CI, 1.10-2.78) in children who did not have positive skin test responses. Higher NO(2) exposure resulted in lower peak flows during colder months (relative risk, 1.46; 95% CI, 1.07-1.97). Higher ETS exposure in colder months was weakly associated with lower peak flows (relative risk, 1.21; 95% CI, 0.99-1.47). There was no effect of ETS exposure on symptoms or use of health care services.

CONCLUSION

Higher levels of indoor NO(2) are associated with increased asthma symptoms in nonatopic children and decreased peak flows.

CLINICAL IMPLICATIONS

Interventions to reduce NO(2) exposure, such as venting of gas stoves, might help reduce asthma morbidity.

Comparison of patterns of allergen sensitization among inner-city Hispanic and African American children with asthma

BACKGROUND

Among Hispanics, the largest minority ethnic group in the United States, asthma prevalence is increasing, particularly in inner-city neighborhoods. Although allergen sensitization among asthmatic African Americans has been extensively studied, similar details are not available for Hispanic children.

OBJECTIVES

To examine patterns of allergen sensitization, including the association with illness severity, in asthmatic children overall and in Hispanic and African American children living in a socioeconomically disadvantaged area of New York City.

METHODS

A retrospective medical record review of asthmatic children attending a community hospital in the South Bronx area of New York City was performed. Information abstracted included demographics, asthma severity classification, reported exposures to indoor allergens, and results of allergy testing.

RESULTS

Among 384 children in the analysis, 270 (70.3%) were Hispanic and 114 (29.7%) were African American. Sensitization to indoor and outdoor allergens, respectively, did not differ between Hispanic (58.5% and 27.0%) and African American (58.8% and 32.6%) children. Allergen sensitization exhibited a direct, significant association with asthma severity for indoor allergens for the 2 ethnic groups combined and for Hispanics separately but not between asthma severity and outdoor allergens (P < .01). No correlation was found between self-reported allergen exposure and sensitization.

CONCLUSIONS

Patterns of allergen sensitization among inner-city Hispanic asthmatic children resemble those among African American children, a finding that is likely explained by the similarity in levels of environmental exposures. With the increasing prevalence of asthma among inner-city Hispanic children, skin testing should be used frequently for objective evaluation of asthma in this ethnic group.

Air pollution: a threat to the health of our children

BACKGROUND/METHODS

Current air pollution levels pose a threat to the health of children starting from conception. The scientific evidence is presented for mortality, morbidity, and sub-clinical effects. The first section deals with exposure data, the following sections with the evidence of health effects from epidemiology and toxicology leading to recommendations.

RESULTS

Improved air quality reduces the number of infants' deaths as well as disease and pain.

CONCLUSIONS

Medical doctors have a responsibility to know the facts and to advise their patients. Doctors when visiting their patients' homes should be aware of the possibly grave impact of the indoor environment for the respiratory health of their patients. They should recognize and advise the parents on problems associated with environmental tobacco smoke, poor ventilation, mould growth, and maintenance of heating installations. With regard to outdoor air pollution, doctors could serve as role models and also advise their patients and parents on environmentally friendly behaviour. Such behaviour not only calls for personal commitment but also for the right infrastructure to be provided (e.g. public transport, district heating). Doctors should be proactive in the community and in their country as advocates for a healthier environment for our children.

Efficacy and safety of allergen immunotherapy in children

OBJECTIVE

To determine the efficacy and safety of immunotherapy in children with allergic rhinitis and allergic asthma.

DATA SOURCES

Current Contents database for 1967 to 2005.

STUDY SELECTION

The expert opinion of the author was used to select studies for inclusion in this review.

RESULTS

Meta-analyses have confirmed the clinical effectiveness of allergen immunotherapy in patients with allergic rhinitis and asthma; however, most studies involved immunotherapy with a single allergen. Special considerations of safety regarding immunotherapy in children are also necessary, since fatalities have been reported. Fatal reactions occur primarily in patients with asthma and particularly those whose asthma is not well controlled. There is probably increased risk during the build-up phase and with the first injection from a new vial. Injections at home or in clinics without adequate supervision also constitute an increased risk of a fatal outcome.

CONCLUSIONS

Specific immunotherapy has been demonstrated to have some protective effect against the development of additional sensitivities in the monosensitized child and to reduce the risk of developing asthma in children with allergic rhinitis. Because of the modification of the underlying immune process, the beneficial effects of immunotherapy persist for a long but not yet fully determined period after the cessation of treatment. This persisting effect makes immunotherapy an attractive supplement to symptomatic treatment of children with allergic asthma and allergic rhinitis. The treatment is not without risk, however, especially in the child with asthma, so it should be administered with caution.

Asthma symptoms in early childhood--what happens then?

AIM

To study the outcome in early adulthood for children with early asthma symptoms and to analyse the factors associated with current asthma.

METHODS

In a prospective study, we have re-investigated 89/101 children who were hospitalized before the age of two years due to wheezing. The children were investigated using a questionnaire and allergy and bronchial hyper-responsiveness tests at the age of 17-20 years and compared with age-matched controls.

RESULTS

In the cohort, 43% had had asthma symptoms in the preceding 12 months compared with 15% in the control group. The strongest risk factors for asthma were current allergy, bronchial hyper-responsiveness and female gender. Female gender and passive smoking in infancy were independent infantile risk factors. In addition to female gender, two pathways led to current asthma: an allergic pathway from family atopy via the development of allergy and another pathway from early passive smoking via hyper-responsiveness and active smoking.

CONCLUSION

In children with early wheezing disorder, current allergy, bronchial hyper-responsiveness and female gender were the strongest risk factors for asthma in early adulthood, while female gender and passive smoking in infancy were independent infantile risk factors. The effects of early passive smoking persist longer than previously reported.

A prospective study of Fel d1 and Der p1 exposure in infancy and childhood wheezing

The impact of domestic exposure to cat allergen (Fel d1) and house dust mite (Der p1) on wheezing from birth to the age of 4 years was investigated in a multicenter prospective birth cohort; 1,611 mothers were recruited before delivery in Ashford, England, and Barcelona and Menorca, Spain. Exposures were gathered via dust sample collection at children's home in their first year of life. Families provided complete outcome data (wheezing status in all 4 years) for 1,289 children. Domestic allergen levels varied substantially between centers. Six hundred three (47%) children never wheezed during their first 4 years of life. Der p1 did not correlate with any type of wheezing outcome. Fel d1 significantly increased the risk of wheezing in 3- and 4-year-olds in comparison to 1-year-olds. Distinct risk profiles were found for wheezing at different ages. Multivariate analysis revealed an interaction between Fel d1 and maternal asthma among children who wheeze in Year 4 (relative risk = 2.77; 95% confidence interval = 1.19-6.46). Our data support the idea that several patterns of wheezing with different risk profiles exist among young children. The effect of Fel d1 exposure varied according to age and maternal asthma.

Comparative prevalence of sensitization to common animal, plant and mould allergens in subjects with asthma, or atopic dermatitis and/or allergic rhinitis living in a tropical environment

BACKGROUND AND OBJECTIVES

Current information suggests that the expression of allergic diseases is determined by the exposure and nature of the allergen. The objectives of the present study were to determine if the nature of allergenic exposition to animal, plant or fungal allergens influenced the clinical manifestations of atopic dermatitis (AD), allergic rhinitis (AR) or asthma (AS) in patients living in a tropical environment. The prevalence and degree of sensitization to these allergens were analysed by age and gender.

SUBJECTS AND METHODS

A total of 1496 atopic cases, grouped according to the primary diagnosis of AD or AR or AS, were skin tested using a standardized allergen panel. Participants were categorized by age groups. The atopic index (AI) and mean weal diameter (MWD) as well as the prevalence of positive skin tests were determined for each of the patient groups and compared by age groups.

RESULTS

The prevalence of atopy as well as the AI and the MWD peaked at 6-15 years of age and declined thereafter. In all the patients tested, the prevalence of sensitization was, in decreasing order; dust mites 94.3%, cockroach 41.5%, pets 31.5%, plant allergens 31.1% and fungal 19.4%. Eight hundred and ninety-three atopic patients were exclusively sensitized only to animal allergens. Of these, 38.4% had AD, 31.3% had AR and 30.5% with AS.

CONCLUSION

These data demonstrate that for patients with AD, AR and AS living in a tropical environment, the prevalence of positive skin reactions to animal allergens is highest followed by plant and fungal allergens. We did not observe any association between the type of allergen and clinical manifestations. The index of atopy was similar for both sexes. The prevalence and degree of sensitization were shown to peak in young adults independent of the allergen in AD and AR patients.

Natural history of asthma

For some children, asthma is a disease whose symptoms seem to remit with time. Numerous children, however, develop disease that is persistent throughout their lifetimes and is associated with more severe symptoms, increased airway reactivity, and loss of lung function. These children typically have a family history of asthma and demonstrate increased airways reactivity and atopy in childhood. A clearer picture of the natural history of asthma in the developing child has been derived from the results of several longitudinal studies. Although some questions have been clarified, several questions still remain. Now that the incidence and severity of asthma seem to be increasing, children born in the last 10 years may experience more severe disease or a different pathophysiology than those born 30 to 40 years ago. New cohort studies are needed to assess this possibility. Additional investigations into the genetics of asthma causation will help elucidate the different phenotypic expressions of this complex disease. Once these different phenotypic groups can be identified early in life, further studies can be performed to explore the impact of therapeutic intervention on the severity of asthma symptoms and loss of lung function.

Exhaled NO level and number of eosinophils in nasal lavage as markers of pollen-induced upper and lower airway inflammation in children sensitive to grass pollen

OBJECTIVES

This study investigates the upper and lower inflammatory response induced by natural exposure to grass pollen in atopic and non-atopic children.

METHODS

After children's atopic profile had been assessed, their nasal lavage fluid (NAL) and exhaled air was sampled once before and once during the pollen season. Level of nitric oxide (NO) was determined in exhaled air, and the following mediators were measured in NAL: ECP, IL-6, IL-8, albumin, uric acid, and urea. The number of eosinophils in NAL was determined after Giemsa staining. During the experiment ozone and pollen levels were measured continuously.

RESULTS

During the pollen season the level of grass pollen was 95 pollen grains per cubic metre. At baseline, 8.0% and 5.4% of total cells in NAL of children sensitive to, respectively, house dust mite (HDM) and pollen + HDM were eosinophils, whereas virtually no eosinophils were observed in NAL of non-atopic children. In contrast to the non-atopic and HDM groups, in children sensitive only to grass pollen, grass pollen induced a threefold increase in the percentage of NAL eosinophils and a 2.5-fold increase in the NAL level of ECP ( P<0.05). In all groups, the NAL levels of albumin, uric acid, urea, IL-6 and IL-8 were not significantly increased by pollen exposure. At baseline, children sensitive to HDM showed significantly higher exhaled nitric oxide (eNO) values than non-atopic subjects and children sensitive only to pollen (79 to 141% increase). During pollen exposure eNO of children sensitive only to pollen increased from 35.8 to 64.5 ppb ( P<0.05), whereas no increase in eNO was observed in the other children.

CONCLUSION

Pollen-sensitive children show a season-dependent upper and lower airway inflammatory response, resembling the continuous inflammation in HDM-sensitive children.

Comparison of multiple environmental factors for asthmatic children in public housing

Nine families of a public housing development in Boston were enrolled in a pilot asthma intervention program designed to gather dense environmental data and generate hypotheses about the relative importance of different contaminants and the viability of interventions. Despite formidable challenges working with this inner-city population, the project team succeeded in gaining active support for the project by forming a partnership with a community-based organization and by building positive relationships between the field team and the residents. Families were provided with physical interventions such as air filters, industrial cleaning and mattress covers to each apartment. Indoor temperature was high and relative humidity low during winter. Insulation of exposed steam pipes did not lower temperature. Cockroach, mouse and pet antigen levels were variable and frequently high in settled dust. Viable fungal spore levels were variable and high in some apartments. Dust-mite allergen levels were below the level of concern. Industrial cleaning led to transient reduction in mouse and cockroach antigen burden. Mattress and pillow covers lowered dust-mite antigen in bedrooms, but not living rooms. Nitrogen dioxide (NO2) levels exceeded ambient concentrations due to use of gas stoves and concentrations of particulate matter with aerodynamic diameter <2.5 microm (PM2.5) were above ambient levels because of smoking. Air filtering systems did not reduce PM levels. Several volatile organic compounds (VOCs) were above adverse risk concentrations. We hypothesize that our findings are consistent with a multifactorial model for exacerbation of asthma in this population and that no single problem dominates.

Family history as a predictor of asthma risk

Asthma, one of the most important chronic diseases of children, disproportionately affects minority and low-income children. Many environmental risk factors for asthma have been identified, including animal, mite, and other allergens; cigarette smoke; and air pollutants. Genetics also play an important causative role, as indicated by familial aggregation and the identification of candidate genes and chromosomal regions linked to asthma risk. Using a positive family history of asthma to identify children at increased risk could provide a basis for targeted prevention efforts, aimed at reducing exposure to environmental risk factors. To assess the predictive value of family history as an indicator of risk for childhood asthma, we reviewed population-based studies that evaluated family history of asthma and atopic disease in children with asthma. Our search identified 33 studies from all geographic regions of the world for review. The studies varied in definitions of positive family history and asthma phenotype and used study populations with asthma prevalence ranging from 2% to 26%. Nevertheless, family history of asthma in one or more first-degree relatives was consistently identified as a risk factor for asthma. In ten studies, sensitivity and predictive value of a positive family history of asthma could be calculated: sensitivity ranged from 4% to 43%, positive predictive value from 11% to 37%, and negative predictive value from 86% to 97%. Although a positive family history predicts an increased risk of asthma, it identifies a minority of children at risk. Positive family history may have utility in targeting some individual prevention efforts, but the low positive predictive value limits its value as a means to direct environmental remediation efforts.

Effects of air pollution on the prevalence and incidence of asthma in children

The effects of air pollution on asthmatic symptoms were assessed in a prospective cohort study of 3,049 schoolchildren in 8 different communities in Japan. Respiratory symptoms in these children were evaluated by questionnaires every year from the 1st through the 6th grades. The prevalence of asthma among the 1st graders was strongly associated with a history of allergic or respiratory diseases, but it was not associated with concentrations of air pollution. During the follow-up period, incidence rates of asthma were associated significantly with atmospheric concentrations of nitrogen dioxide. Particulate matter less than 10 microm in diameter (PM10) was also associated with a higher incidence of asthma, although the association was not significant. These findings suggest that air pollution, including nitrogen dioxide, may be an important factor in the development of asthma among children in urban districts.

Environmental controls in the management of allergic asthma

Environmental allergen control is one of the four primary goals of good asthma management. The American Academy of Allergy, Asthma, and Immunology has published a position statement [78] that endorses the National Asthma Education and Prevention Program management guidelines [23] and recommends that every patient with persistent asthma be evaluated for environmental allergen sensitivity. Patients who have sensitivities should receive practical advice on allergen avoidance. An accumulating body of knowledge indicates that such measures, when strictly applied for a sufficient period of time, can indeed reduce asthma symptoms, need for medication, and airway hyperresponsiveness. Ongoing prospective trials in large numbers of patients are being conducted and should enhance the ability to make proper recommendations to patients.

Sensitisation to airborne moulds and severity of asthma: cross sectional study from European Community respiratory health survey

OBJECTIVE

To assess whether the severity of asthma is associated with sensitisation to airborne moulds rather than to other seasonal or perennial allergens.

DESIGN

Multicentre epidemiological survey in 30 centres.

SETTING

European Community respiratory health survey.

PARTICIPANTS

1132 adults aged 20-44 years with current asthma and with skin prick test results.

MAIN OUTCOME MEASURES

Severity of asthma according to score based on forced expiratory volume in one second, number of asthma attacks, hospital admissions for breathing problems, and use of corticosteroids in past 12 months.

RESULTS

The frequency of sensitisation to moulds (Alternaria alternata or Cladosporium herbarum, or both) increased significantly with increasing asthma severity (odds ratio 2.34 (95% confidence interval 1.56 to 3.52) for either for severe v mild asthma). This association existed in all of the study areas (gathered into regions), although there were differences in the frequency of sensitisation. There was no association between asthma severity and sensitisation to pollens or cats. Sensitisation to Dermatophagoides pteronyssinus was also positively associated with severity. In multivariable logistic regressions including sensitisation to moulds, pollens, D pteronyssinus, and cats simultaneously, the odds ratios for sensitisation to moulds were 1.48 (0.97 to 2.26) for moderate v mild asthma and 2.16 (1.37 to 3.35) for severe v mild asthma (P<0.001 for trend).

CONCLUSIONS

Sensitisation to moulds is a powerful risk factor for severe asthma in adults. This should be taken into account in primary prevention, management, and patients' education.

Environmental tobacco smoke as a risk factor for respiratory disease in children

Respiratory diseases are a frequent reason for using health care. In 1995-1996, diseases of the respiratory tract (ICD 460-519) contributed seven of the top 15 reasons for visits to physician offices among children under 15 years of age in the United States. Environmental tobacco smoke (ETS) is a wide-spread environmental pollutant that has been long linked with respiratory problems. This paper will review the available literature on the role ETS plays in respiratory diseases, including asthma. This review focuses not only on the respiratory problems caused by ETS, but also examines the influence of age at exposure on the consequences of ETS and the importance of the differing sources of ETS exposure. As ETS is a completely preventable form of environmental pollution, the success or failure of various types of interventions will also be reviewed.

Assessment and control of fungal allergens

Fungal sensitivity is a significant cause of allergic disease. Understanding the role fungi play in allergic disease, and how to best control exposure among those with allergy, can have important clinical ramifications.

Quantitation of the major fungal allergens, Alt a 1 and Asp f 1, in commercial allergenic products

BACKGROUND

Alternaria is one of the most important fungi associated with allergic disease, whereas Aspergillus fumigatus is involved in a broad spectrum of pulmonary diseases. Currently, fungal extracts used for diagnosis in the United States are unstandardized, and their allergenic content cannot be compared directly.

OBJECTIVE

The goal of this study was to compare the variability of major allergen levels among US allergenic products derived from fungi: specifically, Alt a 1 levels in Alternaria alternata extracts, and Asp f 1 levels in A fumigatus extracts.

METHODS

A novel 2-site monoclonal antibody ELISA was used for measuring Alt a 1 using recombinant Alt a 1 as a standard. Asp f 1 was also measured by ELISA. Allergenic products produced by 8 US manufacturers over a 2-year period were compared, as were multiple lots produced by a single company.

RESULTS

Alt a 1 levels in Alternaria extracts from 8 companies produced in 1998 and 1999 ranged from less than 0.01 to 6.09 microg/mL (mean 1.4 +/- 1.6 microg/mL, n = 15). In general, Alt a 1 levels were consistent within and between companies (1.4 +/- 1.1 microg/mL, n = 27), with 21 of 32 (66%) of all extracts tested containing 0.7 to 2 microg/mL Alt a 1. Aspergillus extracts showed much greater variability in Asp f 1 levels, with extracts from 8 companies containing from less than 0.1 to 64 microg/mL Asp f 1 (mean 16.3 +/- 23.9 microg/mL, n = 15). Overall variability was greater for Aspergillus products within and between manufacturers (22 +/- 22 microg/mL Asp f 1, n = 20).

CONCLUSIONS

ELISA-based assays for specific allergens showed greater consistency among allergenic products derived from Alternaria than from Aspergillus. These assays should facilitate improved quality control and standardization of fungal allergen extracts and lead to the development of more consistent products for clinical use.

The role and abatement of fungal allergens in allergic diseases

Sensitivity to a variety of fungi is known to be a factor in allergic rhinitis and asthma. In this review methods for measuring exposure to fungi in the indoor environment are evaluated. A variety of markers for the presence of fungi are also described in addition to their known relationship to either toxic or adverse immunologic effects. Key studies documenting the clinical effects of different types of fungi are also reviewed, as well as a description of abatement methods that either have been successful or need further investigation. Although many studies have shown an association between exposure to fungi and allergic disease, in many cases a direct cause-and-effect relationship has not been established. Improved knowledge of the epidemiology and mechanisms behind fungal-induced human disease will hopefully establish this causal link and suggest methods for reducing morbidity.

Assessing the quality of asthma care provided to Medicaid patients enrolled in managed care organizations in Connecticut

BACKGROUND

Many states have enrolled Medicaid beneficiaries in managed care organizations (MCOs). Few assessments of the quality of asthma care provided by these new programs are available.

OBJECTIVE

To describe the quality of care provided to asthmatic Medicaid children enrolled in MCOs.

METHODS

For this cross-sectional survey, a chart abstraction tool was developed to evaluate fulfillment of key performance measures chosen from a national guideline for asthma diagnosis and management. These measures were prescription of an inhaled anti-inflammatory medication, accomplishment of patient education, evaluation of exposure to environmental triggers of asthma, and administration of influenza vaccination. From State of Connecticut administrative databases, a random sampling of Medicaid children, ages 5 to 18 years, enrolled in four MCOs was selected. Chart entries from July 1, 1996 to June 30, 1997 were reviewed using the abstraction tool. Accomplishment of performance measures was evaluated for the total sample and for children who were high utilizers of medical services (at least one ED visit or hospitalization during the study period).

RESULTS

For 80 high utilizers among 315 children, completion of performance measures was suboptimal: 46% were prescribed inhaled steroids; an action plan was outlined for 43%; evaluation of patient or family tobacco use was documented for 56%; evaluation of the presence of a pet for 43% or mite exposure for 19%; and allergy skin testing or RAST was accomplished for 15%.

CONCLUSIONS

This information suggests that opportunities exist to improve the quality of care for these children.

The importance of allergens in the development of asthma and the persistence of symptoms

The importance of allergies and allergens in the development and persistence of asthma is suggested by 3 lines of evidence. First, a number of epidemiologic studies demonstrate that sensitization to indoor allergens and the spores of the outdoor seasonal fungus Alternaria is a risk factor for the development of asthma in both children and adults. Sensitivity to pollens, on the other hand, rarely constitutes a risk for asthma but does constitute a risk for seasonal allergic rhinitis. Second, several studies, again in both children and adults, have demonstrated that, in persons sensitive to indoor allergens, the severity of asthma symptoms will vary with the level of exposure. Third, the elimination of exposure to house-dust mites has produced a remarkable reversal of asthma in sensitive children and adults. Not only have symptoms and pulmonary function improved, but there has also been evidence of a reduction in airway inflammation and hyperresponsiveness. Taken together, these studies make a strong argument for the importance of allergy and allergen exposure as aggravating factors in asthma in both children and adults and reinforce the importance of the identification and treatment of these allergen sensitivities. (J Allergy Clin Immunol 2000;105:S628-32.)

The importance of allergens in the development of asthma and the persistence of symptoms

The importance of allergies and allergens in the development and persistence of asthma is suggested by 3 lines of evidence. First, a number of epidemiologic studies demonstrate that sensitization to indoor allergens and the spores of the outdoor seasonal fungus Alternaria is a risk factor for the development of asthma in both children and adults. Sensitivity to pollens, on the other hand, rarely constitutes a risk for asthma but does constitute a risk for seasonal allergic rhinitis. Second, several studies, again in both children and adults, have demonstrated that, in persons sensitive to indoor allergens, the severity of asthma symptoms will vary with the level of exposure. Third, the elimination of exposure to house-dust mites has produced a remarkable reversal of asthma in sensitive children and adults. Not only have symptoms and pulmonary function improved, but there has also been evidence of a reduction in airway inflammation and hyperresponsiveness. Taken together, these studies make a strong argument for the importance of allergy and allergen exposure as aggravating factors in asthma in both children and adults and reinforce the importance of the identification and treatment of these allergen sensitivities.

Prevalence and severity of asthma, rhinitis, and atopic eczema: the north east study

Using the international study of asthma and allergies in childhood (ISAAC) questionnaire, 3000 children aged 6-7 years from various schools in the north east of England were studied. In this population, the lifetime prevalence rates of various symptoms and diagnoses were: wheezing, 29.6%; atopic eczema, 27.8%; rhinitis, 23. 1%; and self reported asthma, 22.7%. Rhinitis was reported by 44% and 40% of boys and girls with asthma, respectively. Atopic eczema was reported by 46% of both boys and girls with asthma. The prevalence rates of reported asthma, and of symptoms suggestive of asthma, were higher than those reported from studies conducted on UK children in 1992.

Passive smoke exposure in infants and children with respiratory tract diseases

1. The adverse effect of passive smoke exposure on the respiratory tract, particularly in infants and children, is not an issue of dispute. It was the objective of this study to analyse the extent and the intensity of passive smoke exposure in infants and children with respiratory tract diseases, and compare the information obtained with parents' subjective assessment. At the time of admission to the hospital, the parents of 295 infants and children (aged 1 month to 11 years) were questioned by the physician as to the smoking habits in the families' homes. An HPLC method was employed to determine simultaneously nicotine, cotinine and trans-3'-hydroxycotinine in the children's urine. 2. The sum of the nicotine metabolites turned out to be a sensitive marker in determining passive smoke exposure. Measurements revealed passive smoke exposure in 66% of the children, the frequency in younger children being significantly (P < 0.001) higher than in children over 5 years (84% vs 52%). The average concentration of nicotine metabolites in younger passive smokers was significantly (P < 0.001) higher when compared to the older ones (193 nmol/l vs 86 nmol/l). Forty-nine per cent of the parents assessed that their children had experienced passive smoke exposure, and another 10% emphasised that they only smoked in the absence of their child. In children with cystic fibrosis and bronchial asthma, the number of passive smokers as assessed by their parents were lower by 65% and 29% respectively when compared to the findings obtained from measurements. In children without respiratory diseases, the difference was as little as 18%. 3. Parents when questioned in conjunction with an illness of their children, tended to understate, or even withhold the truth about, passive smoke exposure. Therefore, reliable information on passive smoke exposure of patients can only be obtained through objective measurements.

Importance of indoor allergens in the induction of allergy and elicitation of allergic disease

During the last few decades, many countries have experienced an increase in the prevalence and severity of asthma. Over the same period, the population in the developed world has retreated indoors, and homes have become better insulated and more energy efficient, resulting in a warm and humid environment with low ventilation rates, ideally suited to house-dust-mite population growth throughout the year. Increasing exposure and increasing sensitivity to indoor allergens represent a progressively higher risk factor for the development of asthma. The development of sensitivity to indoor allergens and the symptoms and severity of asthma in later childhood are directly related to the exposure to allergens in infancy. It was relatively straightforward to demonstrate a quantitative linear dose-response relationship between exposure to house-dust-mite allergens and subsequent sensitization. However, showing the same for exposure and asthma severity has been more difficult, as the relationship between exposure and asthma symptoms in already sensitized individuals is much more complex than in the case of exposure and sensitization. Nevertheless, sensitized individuals are likely to have more severe asthma if exposed to high allergen levels than if their level of exposure is low. Sensitization to house-dust mites is a major independent risk factor for asthma in all areas where climate is conducive to mite population growth. The relevance of allergens other that mite is not consistent between different areas, and depends on the climate, habits, and socio-economic features of the local community. It would appear that presence of mite allergens in homes "overshadows" other allergens (e.g., cat, dog, or cockroach) as a risk factor for sensitization and subsequent development of allergic disease. It is possible that this is the consequence of the difference in inherent potency between allergen sources, and the question of why mite allergens are so potent in inducing sensitization and atopic disease remains to be answered.

Changing prevalence of allergic rhinitis and asthma

OBJECTIVE

This review will enable the reader to discuss prevalence, risk factors, and prognosis of allergic rhinitis and asthma.

DATA SOURCES

MEDLINE (PubMed) search using the terms allergic rhinitis, asthma, prevalence, risk factors.

STUDY SELECTION

Human studies published in the English language since 1978, especially studies of relatively large populations in the United States, Great Britain, Australia, and New Zealand, with cross referencing to earlier relevant studies.

RESULTS

Current prevalence of allergic rhinitis at 16 years of age in cohorts of British children born in 1958 and 1970 increased from 12% in the earlier cohort to 23% and in the later cohort. Local surveys of allergic rhinitis at approximately 18 years of age in the United States in 1962 to 1965 disclosed prevalence of 15% to 28%, while the national survey of 1976 to 1980 disclosed a prevalence of 26%. Thus, it is uncertain whether prevalence of allergic rhinitis has changed in the United States based on these limited data. Data from several sources indicate worldwide increases in prevalence of asthma. Annual Health Interview surveys indicate increases in prevalence of asthma in the United States from 3.1% in 1980 to 5.4% in 1994, but prevalence among impoverished inner city children has been much higher. Combined prevalence of diagnosed and undiagnosed asthma among inner city children has been 26% and 27% at 9 to 12 years of age in Detroit and San Diego. Positive family history and allergy are important risk factors for allergic rhinitis and asthma. Prognosis is guarded; allergic rhinitis resolves in only 10% to 20% of children within 10 years, and at least 25% of young adults who have had asthma during early childhood are symptomatic as adults.

CONCLUSION

Increases in prevalence remain unexplained, but avoidance of recognized allergens should reduce the prevalence of allergic rhinitis and asthma.

Effect of pre- and postnatal tobacco smoke exposure on specific sensitization to food and inhalant allergens during the first 3 years of life. Multicenter Allergy Study Group, Germany

BACKGROUND

The study aimed to assess the effect of pre- and postnatal tobacco smoke exposure on specific sensitization to food allergens and inhalant allergens during the first 3 years of life.

METHODS

A total of 342 children of a prospective and observational birth cohort study on atopy (MAS) were included on the basis of a complete follow-up of specific IgE measurements at the ages of 1, 2, and 3 years with available questionnaire information about the parental smoking habit at birth, 18 months, and 3 years of age. Study children were grouped into four exposure categories representing in utero and postnatal environmental tobacco smoke (ETS) exposure, and according to the number of cigarettes smoked by the parents. The effect on the development of allergic sensitization to food, outdoor, and indoor allergens by 3 years of age was determined by multiple logistic regression analyses.

RESULTS

At the age of 3, children who were pre- and postnatally exposed to tobacco smoke had a significantly higher risk of sensitization to food allergens (odds ratio: 2.3, 95% C.I.: 1.1-4.6) than unexposed children. Children who were only postnatally exposed by a smoking mother also had a 2.2 times higher risk (95% C.I.: 0.9-5.9) of sensitization than unexposed children. These two categories (pre- and/or postnatal exposure) contribute to the significant overall effect of the tobacco smoke exposure (P< or =0.02). No significant association between tobacco smoke exposure and specific sensitization to inhalant allergens was observed. The determining risk factors for this type of sensitization were atopic family history and mite- and cat-allergen exposure levels.

CONCLUSIONS

During the first 3 years of life, both prenatal and postnatal tobacco smoke exposure has an adjuvant effect on allergic sensitization which seems to be restricted to allergens to which children are mainly exposed, in combination with the peak of the ETS exposure around the first birthday.

Why do only some of the young adults with bronchial hyperreactivity wheeze?

The significance of nonspecific bronchial hyperreactivity (BHR) is a controversial issue in asthma. The natural history of BHR has not been investigated adequately although its importance as a cross-sectional risk factor for asthma is widely accepted. This paper investigates the risk factors for wheeze among people with BHR. Subjects were young adults who had participated in the second phase of the European Community Respiratory Health Survey in Melbourne, Australia. We compared the participants with wheeze and BHR (n=186) to those with asymptomatic BHR (n=66). Information was collected on sociodemographic factors, family history of asthma, and relevant environmental factors using an interviewer-administered questionnaire. Atopy to a range of aeroallergens was examined by skin prick tests. Risk factors were examined by adjusting the odds ratios (OR) by a logistic regression to control for confounding effects. Parental asthma (OR=4.2), keeping pets during childhood (OR=3.3), allergy to house dust mite (OR=2.7), allergic rhinitis (OR=2.6), and having ever smoked (OR=2.4) were associated with an increased risk of wheeze, independent of the other factors examined. When allergic rhinitis was not included as an explanatory variable, being atopic to any of the allergens assessed was found to increase the risk of current wheeze (OR=4.8). Allergic rhinitis may represent an intermediate stage in the natural history of BHR. Avoidance of pets during childhood, not smoking, and taking steps to minimize dust exposure are likely to prevent the progression from asymptomatic BHR to asthma.

Health effects of passive smoking. 6. Parental smoking and childhood asthma: longitudinal and case-control studies

BACKGROUND

The relation of parental smoking to wheezing and asthma occurring after the first year of life was assessed by a systematic quantitative review of case-control and longitudinal studies, complementing earlier reviews of cross sectional surveys and wheezing in early childhood.

METHODS

Fifty one relevant publications were identified after consideration of 1593 abstracts selected by electronic search of the Embase and Medline databases using keywords relevant to passive smoking in children. The search was completed in April 1997 and identified six studies of asthma incidence, seven of prognosis, 22 case-control studies, and 10 case series addressing disease severity.

RESULTS

Maternal smoking was associated with an increased incidence of wheezing illness up to age 6 (pooled odds ratio 1.31, 95% CI 1.22 to 1.41), but less strongly thereafter (1.13, 95% CI 1.04 to 1.22). The long term prognosis of early wheezing illness was better if the mother smoked. The pooled odds ratio for asthma prevalence from 14 case-control studies was 1.37 (95% CI 1.15 to 1.64) if either parent smoked. Four studies suggest that parental smoking is more strongly associated with wheezing among non-atopic children. Indicators of disease severity including symptom scores, attack frequency, medication use, hospital attendance, and life threatening bronchospasm were in general positively related to household smoke exposure.

CONCLUSIONS

The excess incidence of wheezing in smoking households appears to be largely non-atopic "wheezy bronchitis" with a relatively benign prognosis, but among children with established asthma, parental smoking is associated with more severe disease. This apparent paradox may be reconciled if environmental tobacco smoke is considered a co-factor provoking wheezing attacks, rather than a cause of the underlying asthmatic tendency.

Health effects of passive smoking .5. Parental smoking and allergic sensitisation in children

BACKGROUND

A systematic review was conducted of the effects of parental smoking on immunoglobulin (IgE) levels, skin prick positivity, and allergic rhinitis or eczema in children. Asthma was excluded in order to distinguish more clearly the effect of passive smoke exposure on allergic sensitisation.

METHODS

Thirty six relevant publications were identified after consideration of 692 articles selected by electronic search of the Embase and Medline databases using keywords relevant to passive smoking in children. The search was completed in April 1997 and identified nine studies of IgE in neonates, eight of IgE in older children, 12 which included skin prick tests, and 10 describing symptoms of allergic disease other than asthma or wheezing. A quantitative meta-analysis was possible only for the studies reporting skin prick tests.

RESULTS

Several large studies failed to confirm early reports of a substantial or statistically significant association of maternal smoking with concentrations of total serum IgE in neonates or in older children. No consistent association emerged between parental smoking and allergic rhinitis or eczema. Few of these studies adjusted for potential confounding variables. The quantity and quality of evidence was greatest for skin prick tests, and studies of parental smoking during pregnancy or infancy were broadly consistent in showing no adverse effect on prick positivity (pooled odds ratio 0.87, 95% confidence interval 0.62 to 1.24). There was much greater and statistically significant (p = 0.002) heterogeneity of odds ratios relating current parental smoking to skin prick positivity.

CONCLUSIONS

Parental smoking, either before or immediately after birth, is unlikely to increase the risk of allergic sensitisation in children.

Airway function among Inuit primary school children in far northern Quebec

The study of the prevalence and determinants of asthma and allergy in different populations may provide clues to their etiology. We describe airway function and its determinants among Inuit schoolchildren living in far Northern Quebec. We assessed the presence of airways hyperresponsiveness (AHR), defined as a 15% drop in FEV1 with exercise, airflow obstruction, as judged by a reduced FEV1/FVC, and atopy, as evidenced by skin test positivity to inhaled aeroallergens, among 509 Inuit aged mostly from 6 to 13 yr. Smoking by the children (31.9%) and their parents was common, including maternal smoking during pregnancy (79.5%). Atopy was found in only 5.3% of children. Apart from age, there were no significant associations between AHR and any of the determinants examined. Airflow obstruction was present among 7.7% of children and occurred most commonly among children with higher levels of salivary cotinine and in those with four or more lower respiratory illnesses in the first 2 yr of life. Asthma and atopy were uncommon in this population whereas evidence of chronic airflow obstruction was frequently found. Measures to reduce the spread of respiratory infection and prevention of smoking are likely to be of most benefit in improving respiratory health in these isolated communities.

Profile of children requiring emergency treatment for asthma

BACKGROUND

Emergency department care for asthma is expensive and continuity of care is often inefficient. Identification of patients-at-risk for emergency treatment is required in order to intervene before visits to the emergency department.

OBJECTIVE

To identify the antecedent factors in patients requiring emergency department treatment for wheezing and to determine the level of care before emergency visits.

METHODS

A prospective survey of patients treated for wheezing in the emergency department of an academic children's hospital from January 1, 1994 to December 31, 1994. Data were compiled from a data from completed from the information obtained from the medical record, phone calls and letters.

RESULTS

During 1994, 1474 patients were treated for asthma and accounted for 1870 visits to the emergency department. Thirty-six percent of the total number of visits were made by 16% of the patients who made repeat visits. Two-thirds of the patients were 5 years of younger. Over 190 patients had been hospitalized for wheezing during the preceding 12-month period. Forty-four percent of the patients were referred to the emergency department by primary care physicians and 6.7% were referred by asthma specialists, either allergists or pulmonologists. The major predisposing factor was a family history of asthma in 70%. Beta agonists were the medications most frequently used prior to the emergency visits. Inhaled corticosteroids were used daily by 16% of the patients and oral corticosteroids were used daily by 7% of the patients.

CONCLUSION

Thirty-six percent of the visits were due to 16% of patients who were seen repeatedly in the emergency department for wheezing and a number of patients (192) had been admitted previously for wheezing. These findings suggest that there is a subset of patients who are known to have recurrent wheezing, but lack adequate management to avoid expensive hospital services. Very few of these patients were followed by asthma specialists and there was a marked underuse of anti-inflammatory drugs. This study characterized a subset of patients-at-risk for requiring emergency treatment for wheezing. There is a need to institute aggressive interventions to improve the quality of care and prevent costly emergency department visits.