Evolution of asthma through childhood

Severe bronchial hyperresponsiveness along with house dust mite allergy indicates persistence of asthma in young children

BACKGROUND

Significant risk factors for persistence of asthma later in life are family history of allergies, early allergic sensitization and bronchial hyperresponsiveness (BHR). The evolution of BHR in young children without allergic sensitization and with house dust mite allergy (HDM) was investigated.

METHODS

In this retrospective analysis, electronic charts of 4850 young children with asthma and wheezy bronchitis between 2005 and 2018 were reviewed in order to study all patients ≤6 years with BHR assessed by methacholine provocation tests (MCT) at least once (n = 1175). Patients with more than two follow-up measurements were divided in group 1 (no allergic sensitization; n = 110) and group 2 (HDM allergy; n = 88). Additionally, skin prick test, exhaled nitrite oxide (eNO), and asthma treatment were analyzed.

RESULTS

Forty-seven patients of group 1 aged median 4.3 years and 48 patients of group 2 aged median 4.7 years showed initially severe BHR <0.1 mg. At follow-up, patients with HDM were more likely to show persistence of severe BHR than non-sensitized patients (severe BHR group 1: n = 5 (10.6%) vs. group 2: n = 21 (43.8%), p < .001). In addition, 89.4% of group 1 had mild to moderate or no BHR, compared to only 56.2% of group 2. There was a significant difference in eN0 (median group 1: 9 ppb vs. group 2: 26 ppb, p < .001), at last follow-up. Age, sex, and asthma therapy had no effect on BHR.

CONCLUSION

In young children without sensitization BHR normalizes, whereas HDM allergy indicates a persistence of asthma beyond infancy.

The applicability of the global lung initiative equations and other regional equations on a sample of healthy Middle Eastern adolescents

BACKGROUND

The Global Lung Initiative 2012 (GLI-2012) spirometry equations are multi-ethnic equations that cover all ages between 3 and 95. However, there is a need to evaluate the suitability of these equations to a sample of Middle Eastern adolescents prior to being applied in clinical practice. The aim of this study is to evaluate the suitability of GLI-2012 equations and two regional equations to a sample of Jordanian adolescents.

METHODS

Spirometric measures were collected from 1036 healthy 14 to 17-year-old Jordanian children. z-scores, predicted values, percent predicted values, and frequency of measures below lower limit of normal (LLN) were calculated for each adolescent using the studied equations.

RESULTS

The means of z-scores produced by GLI-2012 equations for Caucasians in forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC% and mid forced expiratory flow (FEF25-75) for boys were 0.12, -0.06, 0.34 and 0.09, respectively, while for girls they were -0.09, -0.16, 0.19 and -0.05, respectively. The mean of z-scores produced by GLI-2012 Other or Mixed equations in FEV1, FVC, FEV1/FVC% and FEF25-75 for boys were 0.74, 072, 021 and 0.33, respectively, and for girls were 0.53, 0.56,0.02 and 0.2, respectively. The frequency of measures below LLN as produced by GLI 2012 for Caucasians were significantly different from the expected 5% in FEV1 and FEF25-75 in boys only, whereas Other or Mixed produced frequencies significantly different from the expected 5% in most of the parameters.

CONCLUSION

Spirometry reference equations formulated for Jordanian adolescents may improve the diagnosis and treatment of asthma in Jordan.

Infant formulas containing hydrolysed protein for prevention of allergic disease

BACKGROUND

Infant formulas containing hydrolysed proteins have been widely advocated for preventing allergic disease in infants, in place of standard cow's milk formula (CMF). However, it is unclear whether the clinical trial evidence supports this.

OBJECTIVES

To compare effects on allergic disease when infants are fed a hydrolysed formula versus CMF or human breast milk. If hydrolysed formulas are effective, to determine what type of hydrolysed formula is most effective, including extensively or partially hydrolysed formula (EHF/PHF). To determine whether infants at low or high risk of allergic disease, and whether infants receiving early short-term (first few days after birth) or prolonged formula feeding benefit from hydrolysed formulas.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2017, Issue 11), MEDLINE (1948 to 3 November 2017), and Embase (1974 to 3 November 2017). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles and previous reviews for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

We searched for randomised and quasi-randomised trials that compared use of a hydrolysed formula versus human milk or CMF. Outcomes with ≥ 80% follow-up of participants from eligible trials were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data from the included studies. Fixed-effect analyses were performed. The treatment effects were expressed as risk ratio (RR) and risk difference (RD) with 95% confidence intervals and quality of evidence using the GRADE quality of evidence approach. The primary outcome was all allergic disease (including asthma, atopic dermatitis, allergic rhinitis and food allergy).

MAIN RESULTS

A total of 16 studies were included.Two studies assessed the effect of three to four days infant supplementation with an EHF while in hospital after birth versus pasteurised human milk feed. A single study enrolling 90 infants reported no difference in all allergic disease (RR 1.43, 95% CI 0.38 to 5.37) or any specific allergic disease up to childhood including cow's milk allergy (CMA) (RR 7.11, 95% CI 0.35 to 143.84). A single study reported no difference in infant CMA (RR 0.87, 95% CI 0.52 to 1.46; participants = 3559). Quality of evidence was assessed as very low for all outcomes.No eligible trials compared prolonged hydrolysed formula versus human milk feeding.Two studies assessed the effect of three to four days infant supplementation with an EHF versus a CMF. A single study enrolling 90 infants reported no difference in all allergic disease (RR 1.37, 95% CI 0.33 to 5.71; participants = 77) or any specific allergic disease including CMA up to childhood. A single study reported a reduction in infant CMA of borderline significance (RR 0.62, 95% CI 0.38 to 1.00; participants = 3473). Quality of evidence was assessed as very low for all outcomes.Twelve studies assessed the effect of prolonged infant feeding with a hydrolysed formula compared with a CMF. The data showed no difference in all allergic disease in infants (typical RR 0.88, 95% CI 0.76 to 1.01; participants = 2852; studies = 8) and children (typical RR 0.85, 95% CI 0.69 to 1.05; participants = 950; studies = 2), and no difference in any specific allergic disease including infant asthma (typical RR 0.57, 95% CI 0.31 to 1.04; participants = 318; studies = 4), eczema (typical RR 0.93, 95% CI 0.79 to 1.09; participants = 2896; studies = 9), rhinitis (typical RR 0.52, 95% CI 0.14 to 1.85; participants = 256; studies = 3), food allergy (typical RR 1.42, 95% CI 0.87 to 2.33; participants = 479; studies = 2), and CMA (RR 2.31, 95% CI 0.24 to 21.97; participants = 338; studies = 1). Quality of evidence was assessed as very low for all outcomes.

AUTHORS' CONCLUSIONS

We found no evidence to support short-term or prolonged feeding with a hydrolysed formula compared with exclusive breast feeding for prevention of allergic disease. Very low-quality evidence indicates that short-term use of an EHF compared with a CMF may prevent infant CMA. Further trials are recommended before implementation of this practice.We found no evidence to support prolonged feeding with a hydrolysed formula compared with a CMF for prevention of allergic disease in infants unable to be exclusively breast fed.

WITHDRAWN: Infant formulas containing hydrolysed protein for prevention of allergic disease and food allergy

BACKGROUND

Allergy is common and may be associated with foods, including cow's milk formula (CMF). Formulas containing hydrolysed proteins have been used to treat infants with allergy. However, it is unclear whether hydrolysed formulas can be advocated for prevention of allergy in infants.

OBJECTIVES

To compare effects on allergy and food allergy when infants are fed a hydrolysed formula versus CMF or human breast milk. If hydrolysed formulas are effective, to determine what type of hydrolysed formula is most effective, including extensively or partially hydrolysed formula (EHF/PHF). To determine which infants at low or high risk of allergy and which infants receiving early, short-term or prolonged formula feeding may benefit from hydrolysed formulas.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group supplemented by cross referencing of previous reviews and publications (updated August 2016).

SELECTION CRITERIA

We searched for randomised and quasi-randomised trials that compared use of a hydrolysed formula versus human milk or CMF. Trials with ≥ 80% follow-up of participants were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We independently assessed eligibility of studies for inclusion, methodological quality and data extraction. Primary outcomes included clinical allergy, specific allergy and food allergy. We conducted meta-analysis using a fixed-effect (FE) model.

MAIN RESULTS

Two studies assessed the effect of three to four days' infant supplementation with an EHF whilst in hospital after birth versus pasteurised human milk feed. Results showed no difference in infant allergy or childhood cow's milk allergy (CMA). No eligible trials compared prolonged hydrolysed formula versus human milk feeding.Two studies assessed the effect of three to four days infant supplementation with an EHF versus a CMF. One large quasi-random study reported a reduction in infant CMA of borderline significance among low-risk infants (risk ratio (RR) 0.62, 95% confidence interval (CI) 0.38 to 1.00).Prolonged infant feeding with a hydrolysed formula compared with a CMF was associated with a reduction in infant allergy (eight studies, 2852 infants; FE RR 0.82, 95% CI 0.72 to 0.95; risk difference (RD) -0.04, 95% CI -0.08 to -0.01; number needed to treat for an additional beneficial outcome (NNTB) 25, 95% CI 12.5 to 100) and infant CMA (two studies, 405 infants; FE RR 0.38, 95% CI 0.16 to 0.86). We had substantial methodological concerns regarding studies and concerns regarding publication bias, as substantial numbers of studies including those in high-risk infants have not comprehensively reported allergy outcomes (GRADE quality of evidence 'very low').Prolonged infant feeding with a hydrolysed formula compared with a CMF was not associated with a difference in childhood allergy and led to no differences in specific allergy, including infant and childhood asthma, eczema and rhinitis and infant food allergy. Many of the analyses assessing specific allergy are underpowered.Subroup analyses showed that infant allergy was reduced in studies that enrolled infants at high risk of allergy who used a hydrolysed formula compared with a CMF; used a PHF compared with a CMF; used prolonged and exclusive feeding of a hydrolysed formula compared with a CMF; and used a partially hydrolysed whey formula compared with a CMF. Studies that enrolled infants at high risk of allergy; used a PHF compared with a CMF; used prolonged and exclusive feeding of a hydrolysed formula compared with a CMF; and used a partially hydrolysed whey formula compared with a CMF found a reduction in infant CMA.

AUTHORS' CONCLUSIONS

We found no evidence to support short-term or prolonged feeding with a hydrolysed formula compared with exclusive breast feeding for prevention of allergy. Very low-quality evidence indicates that short-term use of an EHF compared with a CMF may prevent infant CMA.In infants at high risk of allergy not exclusively breast fed, very low-quality evidence suggests that prolonged hydrolysed formula feeding compared with CMF feeding reduces infant allergy and infant CMA. Studies have found no difference in childhood allergy and no difference in specific allergy, including infant and childhood asthma, eczema and rhinitis and infant food allergy.Very low-quality evidence shows that prolonged use of a partially hydrolysed formula compared with a CMF for partial or exclusive feeding was associated with a reduction in infant allergy incidence and CMA incidence, and that prolonged use of an EHF versus a PHF reduces infant food allergy.

Infant formulas containing hydrolysed protein for prevention of allergic disease and food allergy

BACKGROUND

Allergy is common and may be associated with foods, including cow's milk formula (CMF). Formulas containing hydrolysed proteins have been used to treat infants with allergy. However, it is unclear whether hydrolysed formulas can be advocated for prevention of allergy in infants.

OBJECTIVES

To compare effects on allergy and food allergy when infants are fed a hydrolysed formula versus CMF or human breast milk. If hydrolysed formulas are effective, to determine what type of hydrolysed formula is most effective, including extensively or partially hydrolysed formula (EHF/PHF). To determine which infants at low or high risk of allergy and which infants receiving early, short-term or prolonged formula feeding may benefit from hydrolysed formulas.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group supplemented by cross referencing of previous reviews and publications (updated August 2016).

SELECTION CRITERIA

We searched for randomised and quasi-randomised trials that compared use of a hydrolysed formula versus human milk or CMF. Trials with ≥ 80% follow-up of participants were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We independently assessed eligibility of studies for inclusion, methodological quality and data extraction. Primary outcomes included clinical allergy, specific allergy and food allergy. We conducted meta-analysis using a fixed-effect (FE) model.

MAIN RESULTS

Two studies assessed the effect of three to four days' infant supplementation with an EHF whilst in hospital after birth versus pasteurised human milk feed. Results showed no difference in infant allergy or childhood cow's milk allergy (CMA). No eligible trials compared prolonged hydrolysed formula versus human milk feeding.Two studies assessed the effect of three to four days' infant supplementation with an EHF versus a CMF. One large quasi-random study reported a reduction in infant CMA of borderline significance among low-risk infants (risk ratio (RR) 0.62, 95% confidence interval (CI) 0.38 to 1.00).Prolonged infant feeding with a hydrolysed formula compared with a CMF was associated with a reduction in infant allergy (eight studies, 2852 infants; FE RR 0.82, 95% CI 0.72 to 0.95; risk difference (RD) -0.04, 95% CI -0.08 to -0.01; number needed to treat for an additional beneficial outcome (NNTB) 25, 95% CI 12.5 to 100) and infant CMA (two studies, 405 infants; FE RR 0.38, 95% CI 0.16 to 0.86). We had substantial methodological concerns regarding studies and concerns regarding publication bias, as substantial numbers of studies including those in high-risk infants have not comprehensively reported allergy outcomes (GRADE quality of evidence 'very low').Prolonged infant feeding with a hydrolysed formula compared with a CMF was not associated with a difference in childhood allergy and led to no differences in specific allergy, including infant and childhood asthma, eczema and rhinitis and infant food allergy. Many of the analyses assessing specific allergy are underpowered.Subroup analyses showed that infant allergy was reduced in studies that enrolled infants at high risk of allergy who used a hydrolysed formula compared with a CMF; used a PHF compared with a CMF; used prolonged and exclusive feeding of a hydrolysed formula compared with a CMF; and used a partially hydrolysed whey formula compared with a CMF. Studies that enrolled infants at high risk of allergy; used a PHF compared with a CMF; used prolonged and exclusive feeding of a hydrolysed formula compared with a CMF; and used a partially hydrolysed whey formula compared with a CMF found a reduction in infant CMA.

AUTHORS' CONCLUSIONS

We found no evidence to support short-term or prolonged feeding with a hydrolysed formula compared with exclusive breast feeding for prevention of allergy. Very low-quality evidence indicates that short-term use of an EHF compared with a CMF may prevent infant CMA.In infants at high risk of allergy not exclusively breast fed, very low-quality evidence suggests that prolonged hydrolysed formula feeding compared with CMF feeding reduces infant allergy and infant CMA. Studies have found no difference in childhood allergy and no difference in specific allergy, including infant and childhood asthma, eczema and rhinitis and infant food allergy.Very low-quality evidence shows that prolonged use of a partially hydrolysed formula compared with a CMF for partial or exclusive feeding was associated with a reduction in infant allergy incidence and CMA incidence, and that prolonged use of an EHF versus a PHF reduces infant food allergy.

Clinical associations in the diagnosis of vocal cord dysfunction

BACKGROUND

Diagnosis of VCD is complicated by its symptom similarities to asthma. Although clinical history, spirometry, and fiberoptic nasolaryngoscopy are used for VCD diagnosis, videostroboscopy is considered the gold standard. However, little is know about patient characteristics that might suggest a VCD diagnosis is more likely.

OBJECTIVE

To identify clinical characteristics of patients suspected of having VCD that would increase the likelihood of an accurate diagnosis before videostroboscopy.

METHODS

Records of 55 patients were reviewed for a cross-sectional, retrospective study. Individuals selected were suspected of having VCD because of poor clinical response to asthma medications, absence of objective criteria for diagnosis of asthma (eg, normal forced expiratory volume in 1 second without reversibility, normal exhaled nitric oxide, equivocal methacholine challenge test), or both. We used χ² analyses to determine significant univariate associations of various patient characteristics. Multivariate regression analysis was then performed using those variables identified as being significant predictors by univariate analysis.

RESULTS

A significant association between VCD and age and between VCD and shortness of breath (SOB) was found. Further analysis revealed that at ages younger than 35 years, with every 5-year decrement in age, patients suspected of having VCD in which SOB is the presenting symptom are more likely to have a positive VCD diagnosis by a factor of 1.3.

CONCLUSION

Clinical presentation of younger patients with SOB in conjunction with lack of objective criteria for an asthma diagnosis, poor response to asthma medications, or both is highly predictive of VCD and should prompt an objective stroboscopic evaluation to confirm the diagnosis.

Role of infections in the induction and development of asthma: genetic and inflammatory drivers

Genetic and environmental factors interact to initiate and even maintain the course of asthma. As one of the highly risky environmental factors, infections in predisposed individuals can promote asthma development and exacerbations and/or prolong symptoms. This review will describe our current understanding of the genetic markers of innate immunity in the induction and development of asthma, the diverse roles of infections in modulating allergic inflammation, host susceptibility to infections and subsequent acute exacerbations in an allergic setting, and the therapeutic or preventive implications of existing knowledge. Current challenges and future directions in basic and clinical research of asthma are also discussed.

Age at asthma onset and subsequent asthma outcomes among adults with active asthma

INTRODUCTION

Little is known about the extent to which the age at which asthma first began influences respiratory health later in life. We conducted these analyses to examine the relationship between age at asthma onset and subsequent asthma-related outcomes.

METHODS

We used data from 12,216 adults with asthma who participated in the 2010 Behavioral Risk Factor Surveillance System Asthma Call-back Survey to describe the distribution of age at asthma onset. Linear regression was used to estimate associations of age at asthma onset with asthma-related outcomes, including symptoms in the past 30 days and asthma-related emergency visits.

RESULTS

Asthma onset before age 16 was reported by an estimated 42% of adults with active asthma, including 14% with onset at 5-9 years of age who reported experiencing any asthma symptoms on 21% of days in the past month. Compared to this group, the percentage of days in the past month with any asthma symptoms was 14.8% higher (95% confidence interval (CI): 5.4, 24.1) among those whose asthma onset occurred at <1 year. When age at onset occurred at 10 years or older there was little change in the prevalence of asthma-related emergency visits across age at onset categories.

CONCLUSION

Age at asthma onset may affect subsequent asthma-related outcomes.

Local and systemic immunological parameters associated with remission of asthma symptoms in children

The immunological and clinical parameters that are associated with asthma remission are poorly understood. The cytokine and local mediator changes associated with the resolution of asthma symptoms were examined in three groups of subjects 12-18 years of age (n = 15 in each group): (a) continuing asthma group (CA) who had persistent symptoms since early childhood, (b) an age, sex and atopic status-matched group who had persistent symptoms in early childhood but in whom these had resolved (RA), and (c) a non-atopic, non-asthmatic control group. Clinical parameters, sputum cell counts, peripheral blood mononuclear cell (PBMC) cytokine production and activation marker expression were determined. All of the CA had methacholine airway hyperresponsiveness compared with only half of the RA subjects. The CA showed elevated numbers of eosinophils and increased ECP and IL-5 in sputum, which were not observed in the RA. PBMC cytokine studies revealed increased production of the type 1 cytokines IL-12, IFN-γ and TNF-α in the CA group compared with the RA group, under a range of activation conditions, however, the production of IL-4 and IL-5 were unchanged. These findings suggest that decreased type 1 cytokine expression as well as decreased eosinophilic inflammation is associated with the resolution of asthma symptoms.

Longitudinal patterns of poverty and health in early childhood: exploring the influence of concurrent, previous, and cumulative poverty on child health outcomes

Background

Although the links between poverty and health have often been studied , the dynamics of poverty and physical health in early childhood remain under-investigated. In particular, it is not known whether the health of young children is affected differently from that of adults by patterns of poverty unique to them.

Methods

We examined patterns of health from 5 to 41 months of age as a function of concurrent, lagged, and chronic exposure to insufficient income. Using data from the first four rounds of the Quebec Longitudinal Study of Child Development, we performed multilevel logistic and multilevel Poisson regressions and latent growth curve analyses to explore associations between exposure to poverty and mother-reported asthma-like attacks, and maternal perception of health status controlling for neonatal, maternal, and environmental characteristics.

Results

The mean number of mother-reported asthma-like attacks significantly decreased as children aged. The likelihood of being perceived in a poorer health status also decreased across time. Concurrent poverty was associated with more mother-reported asthma-like attacks and with a higher risk of being perceived in poorer health status. One-period-lagged poverty was associated with more mother-reported asthma-like attacks and this remained significant after controlling for concurrent poverty. The number of mother-reported asthma-like attacks was significantly higher among children in the chronic poverty class compared to those in the never-poor class, particularly at 17 and 29 months. Perceived health status at 5-months was significantly poorer among chronically poor children compared to never-poor children.

Conclusion

Exposure to poverty negatively affects two major health indicators in early childhood – maternal perception of child health and mother-reported asthma-like attacks. Patterns of the effects vary according to timing and duration of poverty exposure. Further longitudinal research is warranted to disentangle time-specific from cumulative effects of poverty on child health.

Atopic disorders and parasitic infections

This chapter examines the relationship between atopic disorders and parasitic infections. Atopy is an exaggerated IgE-mediated Type-1 immune response in predisposed individuals. Conflicting information exists in regard to the relationship of parasitic infections and the classic allergic diseases, that is, atopic dermatitis, allergic rhinitis and asthma. Attention is paid to the explanations for these discrepancies in the literature found within both human and animal studies on atopy with particular emphasis on helminthic infections. The factors that cause only a proportion of atopic individuals to develop clinical disease have not been defined although helminths confer protection in many studies examined. Early childhood infections help induce a Th1-biased immunity and prevent the induction of the Th2 system that causes atopy. Acute parasitic infections may increase manifestations of allergy, whereas chronic infections with parasites decrease atopic predisposition. Nonetheless, a causal association between geohelminth infection and atopic disorders has not been established. Some helminthic substances, especially the cytokines, have respiratory and anti-allergic effects, and may therefore become useful as therapeutic modalities for many atopic and allergic disorders.

Chronic stress, salivary cortisol, and alpha-amylase in children with asthma and healthy children

The present study examined whether chronic stress is related to daily life levels of salivary alpha-amylase (sAA), a marker for sympathetic activity, and cortisol in healthy children versus children with asthma. Children's sAA and cortisol levels were measured repeatedly over 2 days. Chronic stress measures included interviews with children about chronic home life stress and interviews with parents about one marker of socioeconomic status, parental education. Among children with asthma, higher chronic stress was associated with lower daily sAA output, while among healthy children, higher chronic stress was associated with flatter cortisol slopes. In conclusion, chronically stressed children with asthma showed lower salivary alpha-amylase output, indicating lower sympathetic activity, and implying a possible mechanism for increased susceptibility to symptom exacerbations. In contrast, higher cortisol levels in healthy children with chronic stress may indicate, for example, an increased risk for infectious diseases. This dichotomy emphasizes the different biological effects of chronic stress depending on illness status.

The challenge of asthma in adolescence

The adolescents with asthma are a distinct group of patients with different problems and needs compared to children and adults. Specific issues of asthma in adolescence are the variability of the clinical spectrum, the presence of particular risk factors for the persistence of symptoms, underdiagnosis and undertreatment of the disease. Refusal of the sick role, denial of symptoms, carelessness about dangerous inhalation exposure, erratic self-medication, overexertion without taking precautions against exercise-induced asthma, and a poor relationship between patients, their families, and often doctors are the main obstacles to successful management of asthma in this critical age. There are also major problems of compliance for these patients. The goal of optimal quality of life will be achieved only if the physician thoroughly understands the adolescent's needs and provides optimal care.

Formulas containing hydrolysed protein for prevention of allergy and food intolerance in infants

BACKGROUND

Allergies and food reactions are common and may be associated with foods including adapted cow's milk formula. Formulas containing hydrolysed proteins have been used to treat infants with allergy or food intolerance. However, it is unclear whether hydrolysed formula can be advocated for prevention of allergy and food intolerance in infants without evidence of allergy or food intolerance.

OBJECTIVES

To determine the effect of feeding hydrolysed formulas on allergy and food intolerance in infants and children compared to adapted cow's milk or human breast milk. If hydrolysed formulas are effective, to determine what type of hydrolysed formula is most effective including extensively and partially hydrolysed formulas. To determine which infants benefit, including infants at low or high risk of allergy and infants receiving early, short term or prolonged formula feeding.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. The review was updated with searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2006), MEDLINE (1966-March 2006), EMBASE (1980-March 2006) and CINAHL (1982-March 2006) and previous reviews including cross references.

SELECTION CRITERIA

Randomised and quasi-randomised trials that compare the use of a hydrolysed infant formula to human milk or cow's milk formula. Trials with >80% follow up of participants were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Eligibility of studies for inclusion, methodological quality and data extraction were assessed independently by each review author. Primary outcomes included clinical allergy, specific allergies and food intolerance. Meta-analysis was conducted using a fixed effects model.

MAIN RESULTS

Two trials compared early, short term hydrolysed formula to human milk feeding. No significant difference in infant allergy or childhood cow's milk allergy (CMA) were reported. No eligible trial compared prolonged hydrolysed formula to human milk feeding. Two trials compared early, short term hydrolysed formula to cow's milk formula feeding. No significant benefits were reported. One large quasi-random study reported a reduction in infant CMA of borderline significance in low risk infants (RR 0.62, 95% CI 0.38, 1.00). Ten eligible studies compared prolonged feeding with hydrolysed formula versus cow's milk formula in high risk infants. Meta-analysis found a significant reduction in infant allergy (seven studies, 2514 infants; typical RR 0.79, 95% CI 0.66, 0.94), but not in the incidence of childhood allergy (two studies, 950 infants; typical RR 0.85, 95% CI 0.69, 1.05). There was no significant difference in infant eczema (eight studies, 2558 infants, typical RR 0.84, 95% CI 0.68, 1.04), childhood eczema incidence (two studies, 950 infants, typical RR 0.83, 95% CI 0.63, 1.10), childhood eczema prevalence (one study, 872 infants; RR 0.66, 95% CI 0.43, 1.02), or infant or childhood asthma, rhinitis and food allergy. One study reported a significant reduction in infants with CMA with confirmed atopy (RR 0.36, 95% CI 0.15, 0.89). Subgroup analysis of trials blinded to formula found no significant difference in infant allergy (four studies, 2156 infants; typical RR 0.87, 95% CI 0.69, 1.08) or childhood allergy incidence (one study, 872 infants; RR 0.91, 95% CI 0.73, 1.14). No eligible trial examined the effect of prolonged hydrolysed formula feeding on allergy beyond early childhood. There is evidence that preterm or low birthweight infants fed a hydrolysed preterm formula have significantly reduced weight gain, but not in other growth parameters (head circumference or length). Studies in term infants report no adverse effects on growth. Subgroup analysis of trials of partially hydrolysed versus cow's milk formula found a significant reduction in infant allergy (six studies, 1391 infants; typical RR 0.79, 95% CI 0.65, 0.97) but not childhood allergy, or infant or childhood asthma, eczema or rhinitis. Methodological concerns were the same as for the overall analysis. Analysis of trials of extensively hydrolysed formula versus cow's milk formula found no significant differences in allergy or food intolerance. Infants fed extensively hydrolysed formula compared with partially hydrolysed formula had a significant reduction in food allergy (two studies, 341 infants; typical RR 0.43, 95% CI 0.19, 0.99), but there was no significant difference in all allergy or any other specific allergy incidence. Comparing extensively hydrolysed casein containing formula with cow's milk formula, one study (431 infants) reported a significant reduction in childhood allergy incidence (RR 0.72, 95% CI 0.53, 0.97). Meta-analysis found a significant reduction in infant eczema (three studies, 1237 infants; typical RR 0.71, 95% CI 0.51, 0.97). One study reported a significant reduction in childhood eczema incidence (RR 0.66, 95% CI 0.44, 0.98) and prevalence (RR 0.50, 95% CI 0.27, 0.92).

AUTHORS' CONCLUSIONS

There is no evidence to support feeding with a hydrolysed formula for the prevention of allergy compared to exclusive breast feeding. In high risk infants who are unable to be completely breast fed, there is limited evidence that prolonged feeding with a hydrolysed formula compared to a cow's milk formula reduces infant and childhood allergy and infant CMA. In view of methodological concerns and inconsistency of findings, further large, well designed trials comparing formulas containing partially hydrolysed whey, or extensively hydrolysed casein to cow's milk formulas are needed.

Worms and allergy

Worms and asthma are associated with a type 2 immune response, but evidence has accumulated that helminth infection is negatively associated with atopy, prevalence of allergic diseases and severity of asthma. One important difference between these polarized type 2 responses is that in allergy modulation of the immunological response is not appropriate, whereas in infection with helminths, several host mechanisms down-regulate the host immune response. As a result, patients infected with worms have a decrease in both type 1 and type 2 responses. The main mechanism involved in this down-modulation is increased production of IL-10, but expansion of regulatory T cells and NKT cells may also participate. Regarding the interaction between worms and allergy, a few variables need to be taken in account: phase (acute or chronic) of helminth infection, parasite load and species of helminth. In animals and humans, acute helminth infection may increase manifestations of allergy, whereas chronic infection with parasites decreases atopy. The modulation of the immune response by helminths is dependent on having an adequate parasite load. Moreover, although several helminth species have been shown to modulate immune responses, most in vitro and in vivo studies have focused on the importance of Schistosoma mansoni in down-modulating allergic reactions.

Percentage fall in FVC at the provocative concentration of methacholine causing a 20% fall in FEV1 in symptomatic asthma and clinical remission during adolescence

BACKGROUND

Many children with asthma go into long-term clinical remission at adolescence, but bronchial hyperresponsiveness (BHR) persists in approximately one half of these subjects. BHR is usually assessed by measuring the provocative concentration of methacholine causing a 20% fall in FEV1 (PC20). The percentage fall in FVC at the PC20 (deltaFVC) has been suggested to be a more useful index of disease severity in asthma than PC20.

STUDY OBJECTIVE

The aim of this study was to determine whether deltaFVC is higher in adolescents with symptomatic asthma than in those with clinical remission.

PATIENTS AND METHODS

Forty adolescents with symptomatic asthma and 80 adolescents with asthma remission underwent methacholine challenge testing. DeltaFVC and PC20 were measured on the methacholine dose-response curve.

RESULTS

The mean (95% confidence interval [CI]) deltaFVC (15.5% [95% CI, 14.1 to 16.9%]) in the symptomatic group (n = 40) was significantly higher (p = 0.017) than that (12.8% [95% CI, 11.5 to 14.1%]) in the BHR-positive (PC20 < 16 mg/mL) remission group (n = 44) or that (11.5% [95% CI, 10.2 to 12.8%]) of the BHR-negative remission group (n = 36), with no difference between the two latter groups (p = 0.581). No significant correlation was found between deltaFVC and PC20 in the symptomatic group (r = -0.156, p = 0.336) or in the whole remission group (r = -0.187, p = 0.097).

CONCLUSIONS

Adolescents with symptomatic asthma had a higher deltaFVC than those with clinical remission, irrespective of the presence of BHR in the latter group. This finding suggests that deltaFVC may serve as an adjunct marker for differentiating between asthma persistence and remission during adolescence.

Peak expiratory flow variability and exercise responsiveness in methacholine-hyperresponsive adolescents with asthma remission

The aim of this study was to investigate whether bronchial hyperresponsiveness in adolescents with long-term asthma remission is associated with increased peak expiratory flow (PEF) variability and/or increased bronchial response to exercise (BRE). Twenty-nine adolescents with asthma remission (neither symptoms nor any medication used during the previous two years), but with persistent methacholine hyperresponsiveness (PC20 < 18 mg/mL; remission group), 29 methacholine PC20-matched adolescents with symptomatic asthma (symptomatic group), and 20 healthy subjects (control group) were studied. Subjects recorded PEF twice daily for 14 days and PEF variability, expressed as amplitude % mean, was calculated. Subjects also underwent a standardized exercise challenge; BRE was defined as a maximal % fall in FEV1 within 30 min after exercise. The mean (+/- SD) PEF variations in the symptomatic group and in the remission group were 12.10 +/- 6.35% and 10.02 +/- 4.73%, respectively, which were significantly higher than that (5.94 +/- 2.44%) of the control group. On the other hand, the degree of BRE (7.36 +/- 3.85%) in the remission group was significantly lower than that (22.31 +/- 10.50%) of the symptomatic group, and similar to that (5.98 +/- 2.70%) of the control group. Methacholine hyperresponsiveness in asthma remission during adolescence is associated with increased PEF variability but not with increased BRE.

Towards improving the accuracy of diagnosing asthma in early childhood

OBJECTIVES

Early and correct diagnosis of asthma in wheezing children is essential for early treatment and prevention of under- or over-treatment. The aim was to study whether combining frequency and age of onset of wheezing illness with respiratory and atopic morbidity at age 0-6 years and sociodemographic parameters for asthma might be helpful for the general practitioner to diagnose asthma early and accurately.

METHODS

Birth cohort, mean follow-up 20 years (SD 4.8) in general practice. The outcome, adolescent asthma, was analysed in relation to wheezing and non-wheezing respiratory and personal and familial atopic morbidity. All diagnoses were from the Continuous Morbidity Registration of the Department of General Practice of the University of Nijmegen, the Netherlands.

RESULTS

1586 (64%) of the children could be followed. Adolescent asthma occurred in 6.4%. There were indications for under- and over-diagnosis of asthma at age 0-6 years. Non-recurrent wheezing (only one episode) and recurrent wheezing (>or =2 episodes) in the first three years of life, and recurrent wheezing at age 4-6 increased the risk with odds ratios (95% confidence interval) of 3.3 (1.9-5.6), 4.7 (2.8-8.2) and 15.4 (7.1-33.7), respectively. The risk additionally increased independently with a family history for asthma, (2.0 [1.1-3.6]), atopic dermatitis (1.7 [1.1-2.7]) and sinusitis (2.9 [1.3-6.4]) and decreased for > or =2nd born children (0.38 [0.19-0.47]) and those with a low social-economic status (0.61 [0.39-0.94]).

CONCLUSION

Easily available history and clinical data may facilitate the early diagnosis of asthma in children with wheezing illness.

Montelukast Reduces Asthma Exacerbations in 2- to 5-Year-Old Children with Intermittent Asthma

The PREVIA study was designed to investigate the role of montelukast, a leukotriene receptor antagonist, in the prevention of viral-induced asthma exacerbations in children aged 2 to 5 years with a history of intermittent asthma symptoms. The study was a 12-month multicenter, double-blind, parallel-group study of patients with asthma exacerbations associated with respiratory infections and minimal symptoms between episodes. Patients were randomized to receive oral montelukast 4 or 5 mg (depending on age) (n = 278) or placebo (n = 271) once per day for 12 months. Caregivers recorded children's symptoms, beta-agonist use, and health care resource use in a diary card. Over 12 months of therapy, montelukast significantly reduced the rate of asthma exacerbations by 31.9% compared with placebo. The average rate of exacerbation episodes per patient was 1.60 episodes per year on montelukast compared with 2.34 episodes on placebo. Montelukast also delayed the median time to first exacerbation by approximately 2 months (p = 0.024), and the rate of inhaled corticosteroid courses (p = 0.027) compared with placebo. Montelukast effectively reduced asthma exacerbations in 2- to 5-year-old patients with intermittent asthma over 12 months of treatment and was generally well tolerated.

Severe asthma

Severe asthma is a term that is commonly used to describe patients with refractory, brittle, near fatal, and difficult-to-control asthma. Patients with severe asthma typically experience persistent symptoms despite medical therapy, report decreased quality of life and suffer an accelerated loss of lung function. The role of genetics, environmental exposure, and infection in the development of more severe asthma is the focus of ongoing research. While pathologic changes in these patients are now believed to involve lung parenchyma, in addition to large and small airways, the independent contribution of each of these compartments to the severe asthma phenotype is not well defined. The clinical evaluation of severe asthma patients should include investigating conditions commonly associated with severe asthma, such as gastroesophageal reflux disease, vocal cord dysfunction, and rhinosinusitis. In addition, advanced imaging techniques, measurement of exhaled gas or sputum indices, and airway biopsy are tools that may aid in evaluating severe asthma patients in the near future. Management of patients with severe asthma requires a comprehensive approach that includes non-pharmacological and pharmacological measures. Combination antiinflammatory and long-acting bronchodilator therapy remains the mainstay of management.

Persistence of asthma symptoms during adolescence: role of obesity and age at the onset of puberty

Little is known about rates and predictors of remission of childhood asthma after the onset of puberty. We used data collected at ages 6, 8, 11, 13, and 16 years from the Tucson Children's Respiratory Study, a population-based birth cohort. The onset of puberty was defined as the age of appearance of the first pubertal signs as reported by parents. Information on wheezing both before and after onset of puberty (mean +/- SD follow-up from onset of puberty, 4.2 +/- 1 year) was available for 781 children. Of these, 166 had asthma (either frequent wheezing or a physician-confirmed diagnosis plus any wheezing) in at least one survey before puberty. In this group, 58% of the children (97 of 166) reported the presence of wheezing after the onset of puberty (unremitting asthma). In contrast, only 30% (39 of 131) of the children with infrequent wheezing before puberty experienced wheezing episodes after the onset of puberty (unremitting wheezing). In addition to frequent wheezing before puberty, obesity, early onset of puberty, active sinusitis, and skin test sensitization were significant and independent predictors of unremitting asthma after the onset of puberty. Our findings from a population-based longitudinal cohort challenge the commonly held view that asthma usually remits during adolescence.

Transfer of asthma management responsibility from parents to their school-age children

This study used grounded theory to explore the process of transfer of responsibility for asthma management from parents to their school-age children. Interviews were conducted with 11 mothers, 2 fathers, 1 grandmother, and their 14 children who were between 8 and 13 years old. Responses revealed that transfer of responsibility within families is a complex, uneven process that occurs over years and involves identifiable stages and transitions. The Theoretical Model for Parent-Child Transfer of Asthma Responsibility emerged from the data. The central concept underlying the process was controlling the situation. Specific cues stimulated changes in parent-child responsibility.

Absence of association of peripheral blood eosinophilia or increased eosinophil cationic protein with bronchial hyperresponsiveness during asthma remission

BACKGROUND

The mechanisms responsible for persistent bronchial hyperresponsiveness (BHR) in adolescents with long-term asthma remission are poorly understood.

OBJECTIVE

To determine whether BHR in adolescents with asthma remission is associated with peripheral blood eosinophilia, increased serum levels of eosinophil cationic protein (ECP), or both findings.

METHODS

We classified 51 adolescents with long-term asthma remission (neither asthma-related symptoms nor medication during the previous 2 years) into 28 BHR-positive patients (methacholine PC20 [provocative concentration causing a 20% decrease in forced expiratory volume in 1 second] <18 mg/mL) and 23 BHR-negative patients. The peripheral blood eosinophil counts and serum ECP concentrations were compared between these 2 groups. Twenty-eight patients with symptomatic asthma (symptomatic group), matched for methacholine PC20 level with study subjects in the BHR-positive remission group, and 28 healthy adolescents (control group) were also studied.

RESULTS

No significant differences in the peripheral blood eosinophil counts (262.1 +/- 117.0/microL vs 253.9 +/- 165.0/microL) and the serum ECP levels (15.6 +/- 10.0 microg/L vs 15.8 +/- 11.9 microg/L) were found between the BHR-positive and BHR-negative remission groups, respectively. The BHR-positive remission group differed from the symptomatic group (372.9 +/- 190.3/microL, P < 0.05; 26.6 +/- 11.3 microg/L, P < 0.01) in both blood indices but resembled the control group (214.6 +/- 118.6/microL and 12.1 +/- 4.8 microg/L; both, no significant difference).

CONCLUSIONS

BHR in adolescents with long-term asthma remission is not associated with peripheral blood eosinophilia or an increase in serum ECP concentration. This finding suggests that the mechanism underlying BHR in this clinical setting may differ from that in symptomatic asthma.

Bronchial hyperresponsiveness in adolescents with long-term asthma remission: importance of a Family history of bronchial hyperresponsiveness

BACKGROUND

The mechanisms responsible for bronchial hyperresponsiveness (BHR) in symptomatic asthma include genetic predisposition and airway inflammation, but the causes of BHR in adolescents with asthma remission are poorly understood. It has been shown that BHR in adolescents with asthma remission was not reduced by prolonged treatment with inhaled corticosteroids, in contrast to the BHR of symptomatic asthma.

OBJECTIVE

The aim of this study was to investigate whether family history of BHR may contribute to the persistence of BHR in asthma remission during adolescence.

METHODS

One hundred twenty-six adolescents with long-term asthma remission (neither symptoms nor any medication used during the previous 2 years) and their parents underwent a methacholine inhalation test. The provocative concentration of methacholine causing a 20% fall in FEV(1) (PC(20)) and the bronchial responsiveness (BR) index were calculated for each individual.

RESULTS

Sixty-nine adolescents (54.8%) were found to have persisting BHR (PC(20) < 18 mg/mL). The frequency of BHR and the BR index were significantly higher in parents (n = 138) of the BHR-persisting group (28.3% and 1.150 +/- 0.103, respectively [mean +/- 1 SD]) than in parents (n = 114) of BHR-nonpersisting group (16.7% [p = 0.030] and 1.124 +/- 0.088 [p = 0.029], respectively). Furthermore, adolescents (n = 56) with at least one BHR-positive parent were found to have a higher frequency of BHR (66.1% vs 45.7%, p = 0.023) and a higher BR index (1.244 +/- 0.090 vs 1.204 +/- 0.082, p = 0.011) than adolescents (n = 70) with non-BHR parents.

CONCLUSION

Our results suggest that adolescents in asthma remission are more likely to have BHR when there is a family history of BHR. Further studies are needed to examine the possible involvement of genetic factors in the BHR of adolescents in asthma remission.

Longitudinal follow-up of the changing gender ratio in asthma from childhood to adulthood: role of delayed manifestation in girls

Boys suffer more often from asthma than girls, while in adults the gender ratio is reversed. It is not clear when exactly this change occurs and by what mechanism. From a cohort of all 5030 German 4th grade pupils (age 10 years) in Munich, 274 children with current asthma were identified (164 males, 110 females) through a questionnaire, and skin prick tests were performed. These subjects were re-evaluated at ages 14 and 20 years with a questionnaire. A random sample (n = 1000) of all 3538 German children without current asthma at age 10 was also re-evaluated at age 20 (controls). At age 20, only 24.5% (21 males, eight females) of the initial asthma group still had symptoms, and their gender ratio remained male dominated. In the controls, 4.8% (48/1000) had current asthma at age 20 and these were predominantly female: 6.4% (31/485) of control girls vs. 3.3% (17/515) of boys (p = 0.022). Half of the new asthma cases had had no symptoms or diagnoses until age 10, and atopy at age 10 was not associated with subsequent asthma in these. Asthma at age 10 has no better prognosis in boys than in girls, and the mechanism of the changing gender ratio appears to be late incidence of asthma among girls. Because the latter constitute a considerable part of adult asthma cases, it appears important to further explore this asthma phenotype and the risk factors associated with it.

Developmental and pediatric pharmacogenomics

Children, as well as adults, should benefit from the discoveries of the genomic era. Many diseases with complex etiologies originate during childhood (e.g., asthma, autism, attention deficit/hyperactivity disorder, epilepsy and juvenile rheumatoid arthritis) and persist into adulthood. Attempts to better understand the genetic basis of age-specific disease processes requires an appreciation that the period of human development encompasses the prenatal period through adolescence, and is a rapidly changing, dynamic process. As a result, pharmacologic modulation of developing gene networks may have unintended and unanticipated consequences that do not become apparent or relevant until later in life. Thus, there is considerable potential for large-scale pharmacogenomic technologies to impact the development and utilization of new therapeutic strategies in children.

Treatment compliance, passive smoking, and asthma control: a three year cohort study

AIMS

To study the role of treatment compliance and parents' smoking on asthma control in children with recently diagnosed mild or moderate persistent asthma who were prescribed inhaled anti-inflammatory treatment.

METHODS

Prospective cohort study of 167 children aged 6-12 years (64% boys). Patients were examined at inclusion and followed up for three years with a visit every four months. Peak expiratory flow (PEF) was measured twice a day during the week before each visit. Two control criteria were monitored: (1) symptom control = having diurnal or nocturnal exacerbations less than once a week and no symptoms between exacerbations, at all visits; and (2) PEF control = daily PEF variability <20% on each of the seven days before each visit.

RESULTS

Symptom control was achieved by 25.1% of children and PEF control by 53.3%. Symptom control was positively related to having understood the way in which the medication worked and taking the prescribed doses (odds ratios (OR) = 3.38 and 4.82 respectively). It was inversely related to smoking within the home (OR = 0.34). PEF control was positively related to taking the prescribed doses (OR = 3.58). It was less frequently achieved if the mother smoked within the home (OR = 0.34).

CONCLUSIONS

Results suggest that, to maximise the benefits of available asthma medication and to improve health outcomes, further efforts should be made to convince the parents of asthmatic children not to smoke in the house, and to improve compliance by increasing the patients' understanding of the disease and its treatment.

The prognosis of bronchial asthma in childhood in Hungary: a long-term follow-up

The aim of this study was to determine the prognosis of bronchial asthma in childhood in Hungary. One hundred and forty five adults (96 men and 49 women) with a clinical history of childhood bronchial asthma were examined at the age of 28 years or above (mean age 37.6, SD 5.9 years). The patients completed questionnaires concerning their asthmatic and accompanying allergic symptoms in childhood, at the age of 18 and at present. They were all prick-tested with 12 inhalant allergens. The results showed that 42.8% of the patients had become symptom-free, but 57.2% still had intermittent or persisting asthmatic symptoms in adulthood. More patients had intermittent day-time (59%) and night-time (67%) asthmatic symptoms than persistent symptoms (41% and 33%). Accompanying allergic diseases (rhinitis, conjunctivitis, dermal and gastrointestinal diseases, and drug andfood allergies) in childhood did not definitely affect the prognosis of the bronchial asthma. The proportion of females with allergic diseases increased, and among patients with skin diseases it was significantly higher than the proportion of affected males. At the age of 18, allergic rhinitis was more frequent than in childhood. The frequencies of other allergic disorders did not change significantly. In the patients with asthmatic symptoms, molds and cat-hair allergies were more frequent than in the symptom-free group. The long-term prognosis of bronchial asthma in childhood in Hungary is relatively good, but fewer than half of the patients became symptom-free. The complaints of most of the patients were mild, but one in seven of all the adults suffered from moderate or serious bronchial asthma. Household allergens may contribute to the persistence of asthmatic symptoms.

Wheezing requiring hospitalization in early childhood: predictive factors for asthma in a six-year follow-up

Although asthma is common after wheezing in early childhood, the risk factors for and the prevention of later asthma are poorly understood. During the present follow-up study, a range of possible predictive factors for school-age asthma was evaluated. The study group consisted of 82 children hospitalized for wheezing at age < 2 years in 1992-93. The baseline data were collected on entry to the study. In 1999, the children were re-examined at the median age of 7.2 years. A structured questionnaire was applied to chart the symptoms suggestive of asthma, and the children were examined clinically. An exercise challenge test, as well as skin prick tests (SPT) to common inhalant allergens, was performed. Asthma was present in 33 (40%) children, 30 (91%) having continuous medication for asthma. The significant asthma-predictive factors, present on entry to the study, were blood eosinophilia (p = 0.0008), atopic dermatitis (p = 0.0089), elevated total serum immunoglobulin E (IgE) (p = 0.0452), and a history of earlier episodes of wheezing in infancy (p = 0.0468). SPT positivity in early childhood was also associated with school-age asthma (p = 0.002). In contrast, respiratory syncytial virus (RSV) identification during the index episode of wheezing played a minor role as a predictive factor for asthma. In conclusion, if hospitalization for wheezing occurs in infancy, more than every third child will suffer from asthma at early school age; the risk is significantly increased with recurrent wheezing in infancy and the development of allergic manifestations.

Maximal airway response in adolescents with long-term asthma remission and persisting airway hypersensitivity: its profile and the effect of inhaled corticosteroids

BACKGROUND

Many children with asthma go into long-term clinical remission at adolescence, but bronchial hyperresponsiveness (BHR) persists in some of these subjects. BHR in asthma is characterized by an increase in sensitivity and in maximal airway response to bronchoconstrictor stimuli.

OBJECTIVE

The aims of this study were to compare the profiles of maximal airway response between adolescents with asthma remission and adolescents with symptomatic asthma to a similar degree of airway hypersensitivity, and to determine whether maximal airway response in adolescents with asthma remission is reduced by prolonged treatment with inhaled corticosteroids.

METHODS

A high-dose methacholine inhalation test was performed in 46 adolescents with long-term asthma remission (remission group) and 44 adolescents with symptomatic asthma (symptomatic group). Subjects exhibiting a maximal response plateau in the remission group were administered inhaled budesonide (400 microg bid, budesonide/remission group, n = 15) or identical placebo (placebo/remission group, n = 15) for 6 months, and the subjects in the symptomatic group were administered the same regimen of budesonide (budesonide/symptomatic group, n = 17). The plateau level was measured after 3 months and 6 months of treatment.

RESULTS

Thirty-four subjects (73.9%) in the remission group featured a maximal response plateau on the dose-response curve to methacholine, whereas 19 subjects (43.2%) in the symptomatic group had a plateau (p = 0.003). In neither the placebo/remission group nor the budesonide/remission group did the plateau level change significantly over the 6-month period, whereas budesonide markedly decreased the level in the budesonide/symptomatic group.

CONCLUSION

The difference in frequency of detection of a plateau between the remission group and the symptomatic group, as well as the difference in its response to treatment with budesonide between the two groups, suggests that inflammatory changes impact the maximal airway response in symptomatic asthmatic adolescents but not in adolescents with asthma remission.

The role of antileukotrienes in the treatment of asthma

Cysteinyl leukotrienes (Cys-LTs) are mediators released in asthma and are both direct bronchoconstrictors and proinflammatory substances that mediated several steps in the pathophysiology of chronic asthma, including inflammatory cells recruitment, vascular leakage, and possibly airway remodelling. Available evidence from clinical trials and real world experience derived from managing patients with asthma justifies a broader role for antiLTRAs in asthma management than that recommended in the National Asthma Education and Prevention Programm (NAEPP) and National Health Lung and Blood Institute (NHLBI) treatment guidelines. Leukotriene-receptor antagonist drugs (LTRAs) seem to be effective alternatives to inhaled corticosteroids (ICS) either as monotherapy or as adjunctive therapy that reduces the need for higher doses of ICS in patients with mild-to-moderate persistent asthma. LTRAs may be used as adjunctive therapy for al levels of disease severity because they are effective in combination with ICS during long-term maintenance therapy. The agents seem especially effective in preventing aspirin-induced asthma, exercise-induced asthma (EIA) and they may provide an additional advantage of reducing nasal congestion in patients with both asthma and rhinitis.

Incidence and remission of asthma: a retrospective study on the natural history of asthma in Italy

BACKGROUND

The knowledge of the natural history of asthma from birth to adulthood could provide important clues for its cause and for the understanding of epidemiologic findings.

OBJECTIVE

This study is aimed at assessing the incidence and remission of asthma from birth to the age of 44 years by using data from 18,873 subjects involved in a large, nationally representative, cross-sectional study carried out in Italy from 1998 through 2000.

METHODS

The onset of asthma was defined as the age at the first attack, and remission was considered present when a subject was neither under treatment nor had experienced an asthma attack in the last 24 months. Person-years and survival techniques were used for the analysis.

RESULTS

The average annual incidence rate for the 1953 to 2000 period was 2.56/1000 persons per year. Incidence peaked in boys less than 10 years of age (4.38/1000 persons per year) and in women 30 years of age or older (3.1/1000 persons per year) and showed a generational increase (incident rate ratio = 2.63 and 95% CI = 2.20-3.12 for 1974-1979 vs 1953-1958 birth cohort). The overall remission rate was 45.8% (41.6% in women and 49.5% in men, P <.001). Asthmatic patients in remission had an earlier age at onset (7.8 vs 15.9 years, P <.001) and a shorter duration of the disease (5.6 vs 16.1 years, P <.001) than patients with current asthma. The probability of remission was strongly (P <.001) and inversely related to the age at onset (62.8% and 15.0% in the <10- and > or =20-years age-at-onset groups, respectively).

CONCLUSION

With respect to its natural history, asthma presents 2 different forms: early-onset asthma, which occurs early in childhood, affects mainly boys, and has a good prognosis, and late-onset asthma, which generally occurs during or after puberty, mainly affects women, and has a poor prognosis. The minority of patients with early-onset asthma who do not remit represents more than 35% of patients with current asthma in the general young adult population.

Effect of inhaled budesonide on bronchial hyperresponsiveness in adolescents with clinical remission of asthma

STUDY OBJECTIVE

Many children with asthma go into long-term clinical remission at adolescence, but bronchial hyperresponsiveness (BHR) persists in some of these subjects. The regular use of inhaled corticosteroids improves BHR in patients with symptomatic asthma. The aim of this study was to determine whether BHR in adolescents with asthma remission could be reduced by prolonged treatment with inhaled corticosteroids.

DESIGN

A randomized, double-blind, placebo-controlled, parallel study.

PATIENTS

Thirty-seven adolescents with BHR and long-term remission of their asthma (neither symptoms nor any medication use during the previous 2 years).

INTERVENTION

Subjects received inhaled budesonide (two 200-microg puffs bid; budesonide group, n = 19) or identical placebo (placebo group, n = 18) for 9 months. A separate group of patients with symptomatic asthma (symptomatic group, n = 19), using the same regimen of budesonide, was also studied.

MEASUREMENTS AND RESULTS

The provocative concentration of methacholine producing a 20% fall in FEV(1) (PC(20)) was measured before and every 3 months during treatment. There was no significant difference among the three groups for the baseline PC(20). In neither the placebo nor the budesonide group did the geometric mean of PC(20) change significantly over the 9-month period. In contrast, a significant increase in PC(20) was noted in the symptomatic group as a result of the budesonide treatment.

CONCLUSION

Our data have shown that budesonide inhaled regularly for 9 months did not cause a significant improvement in the BHR of adolescents with long-term asthma remission. This suggests that the mechanism underlying BHR in this clinical setting may be different from that in symptomatic asthma.

Preferential prescribing of oral corticosteroids in Irish male asthmatic children

AIMS

To determine if there is a gender difference in the prescription of oral corticosteroids in asthmatic children (< 15 years).

METHODS

8072 asthmatics were identified on the basis that they received a prescription for either an inhaled beta-adrenoceptor agonist, an inhaled corticosteroid, inhaled cromoglycate/nedocromil sodium, oral xanthines or leukotriene antagonist. Odds ratios (OR) and 95% confidence intervals (CI) were determined for the different asthma treatments for males compared with females.

RESULTS AND CONCLUSIONS

Male asthmatic children were more likely (OR = 1.37, 95% CI = 1.21,1.55, P < 0.001) to receive a prescription for an oral corticosteroid compared with their female counterparts suggesting a possible increased severity of their condition, rather than a different management of their disease. Male asthmatic children were less likely to be prescribed an antibiotic over the study period (OR = 0.85, 95% CI = 0.77, 0.93, P < 0.001).

Montelukast, a leukotriene receptor antagonist, for the treatment of persistent asthma in children aged 2 to 5 years

BACKGROUND

The greatest prevalence of asthma is in preschool children; however, the clinical utility of asthma therapy for this age group is limited by a narrow therapeutic index, long-term tolerability, and frequency and/or difficulty of administration. Inhaled corticosteroids and inhaled cromolyn are the most commonly prescribed controller therapies for young children with persistent asthma, although very young patients may have difficulty using inhalers, and dose delivery can be variable. Moreover, reduced compliance with inhaled therapy relative to orally administered therapy has been reported. One potential advantage of montelukast is the ease of administering a once-daily chewable tablet; additionally, no tachyphylaxis or change in the safety profile has been evidenced after up to 140 and 80 weeks of montelukast therapy in adults and pediatric patients aged 6 to 14 years, respectively. To our knowledge, this represents the first large, multicenter study to address the effects of a leukotriene receptor antagonist in children younger than 5 years of age with persistent asthma, as well as one of the few asthma studies that incorporated end points validated for use in preschool children.

OBJECTIVE

Our primary objective was to determine the safety profile of montelukast, an oral leukotriene receptor antagonist, in preschool children with persistent asthma. Secondarily, the effect of montelukast on exploratory measures of asthma control was also studied. DESIGN AND STATISTICAL ANALYSIS: We conducted a double-blind, multicenter, multinational study at 93 centers worldwide: including 56 in the United States, and 21 in countries in Africa, Australia, Europe, North America, and South America. In this study, we randomly assigned 689 patients (aged 2-5 years) to 12 weeks of treatment with placebo (228 patients) or 4 mg of montelukast as a chewable tablet (461 patients) after a 2-week placebo baseline period. Patients had a history of physician-diagnosed asthma requiring use of beta-agonist and a predefined level of daytime asthma symptoms. Caregivers answered questions twice daily on a validated, asthma-specific diary card and, at specified times during the study, completed a validated asthma-specific quality-of-life questionnaire. Physicians and caregivers completed a global evaluation of asthma control at the end of the study. Efficacy end points included: daytime and overnight asthma symptoms, daily use of beta-agonist, days without asthma, frequency of asthma attacks, number of patients discontinued because of asthma, need for rescue medication, physician and caregiver global evaluations of change, asthma-specific caregiver quality of life, and peripheral blood eosinophil counts. Although exploratory, the efficacy end points were predefined and their analyses were written in a data analysis plan before study unblinding. At screening and at study completion, a complete physical examination was performed. Routine laboratory tests were drawn at screening and weeks 6 and 12, and submitted to a central laboratory for analysis. Adverse effects were collected from caregivers at each clinic visit. An intention-to-treat approach, including all patients with a baseline measurement and at least 1 postrandomization measurement, was performed for all efficacy end points. An analysis-of-variance model with terms for treatment, study center and stratum (inhaled/nebulized corticosteroid use, cromolyn use, or none) was used to estimate treatment group means and between-group differences and to construct 95% confidence intervals. Treatment-by-age, -sex, -race, -radioallergosorbent test, -stratum, and -study center interactions were evaluated by including each term separately. Fisher's exact test was used for between-group comparisons of the frequency of asthma attacks, discontinuations from the study because of worsening asthma, need for rescue medication, and the frequencies of adverse effects. Because of an imbalance in baseline values for eosinophil counts for the 2 treatment groups, an analysis of covariance was performed on the eosinophil change from baseline with the patient's baseline as covariate.

STUDY PARTICIPANTS

Of the 689 patients enrolled, approximately 60% were boys and 60% were white. Patients were relatively evenly divided by age: 21%, 24%, 30%, and 23% were aged 2, 3, 4, and 5 years, respectively. For 77% of the patients, asthma symptoms first developed during the first 3 years of life. During the placebo baseline period, patients had asthma symptoms on 6.1 days/week and used beta-agonist on 6.0 days/week.

RESULTS

In over 12 weeks of treatment of patients aged 2 to 5 years, montelukast administered as a 4-mg chewable tablet produced significant improvements compared with placebo in multiple parameters of asthma control including: daytime asthma symptoms (cough, wheeze, trouble breathing, and activity limitation); overnight asthma symptoms (cough); the percentage of days with asthma symptoms; the percentage of days without asthma; the need for beta-agonist or oral corticosteroids; physician global evaluations; and peripheral blood eosinophils. The clinical benefit of montelukast was evident within 1 day of starting therapy. Improvements in asthma control were consistent across age, sex, race, and study center, and whether or not patients had a positive radioallergosorbent test. Montelukast demonstrated a consistent effect regardless of concomitant use of inhaled/nebulized corticosteroid or cromolyn therapy. Caregiver global evaluations, the percentage of patients experiencing asthma attacks, and improvements in quality-of-life scores favored montelukast, but were not significantly different from placebo. There were no clinically meaningful differences between treatment groups in overall frequency of adverse effects or of individual adverse effects, with the exception of asthma, which occurred significantly more frequently in the placebo group. There were no significant differences between treatment groups in the frequency of laboratory adverse effects or in the frequency of elevated serum transaminase levels. Approximately 90% of the patients completed the study.

CONCLUSIONS

Oral montelukast (4-mg chewable tablet) administered once daily is effective therapy for asthma in children aged 2 to 5 years and is generally well tolerated without clinically important adverse effects. Similarly, in adults and children aged 6 to 14 years, montelukast improves multiple parameters of asthma control. Thus, this study confirms and extends the benefit of montelukast to younger children with persistent asthma.

Systematic review: Exposure to pets and risk of asthma and asthma-like symptoms

BACKGROUND

Studies of exposure to pets and risk of asthma have yielded conflicting results.

OBJECTIVES

We performed a systematic review to synthesize the evidence of the effect of exposure to pets in the home on the risk of asthma and asthma-related symptoms. We also assessed differences between the studies as sources of heterogeneity of the results.

METHODS

We conducted a MEDLINE search (until the end of 1999) using the following boolean search command: (asthma[all] OR wheez*[all]) AND (domestic animal*[all] OR pets[all]). The outcome was limited to either diagnosis of asthma or the symptom of wheezing. The exposure of interest was domestic animals in the home. Appropriate temporal relationship was defined as present in studies with either pet keeping within the first 2 years of life, in the past, or exposure to pets preceding the outcome.

RESULTS

Thirty-two of the 217 retrieved articles fulfilled the eligibility criteria. Inappropriate time sequence of the exposure and outcome information was an important source of heterogeneity and an indication of potential selection bias. Therefore we analyzed studies focusing on early exposure or ensuring appropriate temporal sequence. The pooled risk estimates for both asthma (fixed-effects odds ratio, 1.11; 95% CI, 0.98-1.25; heterogeneity, P =.04; random-effects odds ratio, 1.09; 95% CI, 0.89-1.34) and wheezing (fixed-effects odds ratio, 1.19; 95% CI, 1.05-1.35; heterogeneity, P =.03; random-effects odds ratio, 1.17; 95% CI, 0.95-1.44) indicated a small effect, which was limited to studies with a median study population age of over 6 years (fixed-effects odds ratio, 1.19; 95% CI, 1.02-1.40; heterogeneity, P =.04; random-effects odds ratio, 1.15; 95% CI, 0.86-1.56; fixed-effects odds ratio, 1.29; 95% CI, 1.12-1.48; heterogeneity, P =.31). In younger children the harmful effect disappeared for wheezing (odds ratio, 0.80; 95% CI, 0.59-1.08; P =.38).

CONCLUSION

Exposure to pets appears to increase the risk of asthma and wheezing in older children. The observed lower risk among exposed than among unexposed young children is consistent with a protective effect in this age group but could also be explained by selection bias.

The burden of childhood asthma

Paediatric asthma is a major clinical concern worldwide and represents a huge burden on family and society. It accounts for a large number of lost school days and may deprive the child of both academic achievement and social interaction. Childhood asthma also places strain on healthcare resources as a result of doctor and hospital visits and the cost of treatment. The prevalence of asthma varies worldwide, possibly because of different exposure to respiratory infection, indoor and outdoor pollution, and diet. Certain risk factors appear to predispose children to developing asthma and atopic disease, including incidence and severity of wheezing, atopy, maternal smoking, and number of fever episodes. This paper discusses the burden, prevalence, and risk factors associated with paediatric asthma.

Childhood asthma: causes, epidemiological factors and complications

Asthma is common in children and its prevalence in this age group is increasing. While the reasons for this reported increase, and indeed the true magnitude of the increase, remain unclear, there can be no doubt that asthma is now a major health problem in children worldwide. Fortunately, our knowledge of the pathophysiology of asthma is also increasing. It is now known that asthma is a chronic inflammatory disease regulated by a variety of mediators, of which perhaps the leukotrienes are among the most important. This new understanding of the pathophysiology of the disease has spurred the development of the antileukotriene agents, which can be expected to play an increasingly important role in the management of childhood asthma.

Involuntary smoking and asthma

Involuntary smoking is the third leading preventable cause of death, and among children it causes lower respiratory infections, middle ear disease, sudden infant death syndrome, and asthma. Half the world's children may be exposed to environmental tobacco smoke (ETS), exacerbating symptoms in 20% of children with asthma. Recent studies have reinforced previous conclusions that ETS exposure causes onset of childhood asthma and exacerbation of symptoms throughout life. The exact mechanisms by which this is accomplished are still unclear, as are the relative contributions of prenatal versus postnatal exposure. However, favorable health outcomes can be attained with reduced exposure. Among the few studies of ETS exposure reduction interventions, low-intensity advice methods appeared ineffective, and counseling parent smokers appeared successful. Direct counseling of school-aged children to avoid ETS has yet to be tested. Community norms may need to shift further in favor of protecting children and others from ETS before minimal interventions can be successful. This will require combined and ongoing efforts of the medical and public health establishments, in concert with legislation mandating tobacco-free public places and with ETS-related media campaigns.

What can we learn from late-onset and occupational asthma?

Late-onset asthma and occupational asthma may provide interesting models of human asthma to compare with the most frequent type of atopic early-onset asthma. The discovery of similarities and discrepancies in the aetiology and pathogenesis of these different diseases might provide new insights on different mechanisms producing the same phenotype and, thus, by recognizing the different underlying mechanisms of the different forms of asthma, may allow better targeting of prevention and treatment. Occupational asthma, in addition to being a late-onset asthma, provides the unique opportunity to study the development of asthma under measurable exposure conditions, and consequently to examine the effect of cessation of exposure which, at variance with allergen avoidance, is possible in most of the cases.