Continuing increase in respiratory symptoms and atopy in Aberdeen schoolchildren

Associations of childhood allergies with parental reproductive and allergy history

PURPOSE

There has been a noted parallel rise in both the use of Assisted Reproductive Technology (ART) to conceive and childhood allergies in the last few decades. The purpose of this study was to investigate the possible association between reproductive and allergy history in parents and allergies in their children.

METHODS

This exploratory study used a cross-sectional study design and web-based survey to collect anonymous data on demographics, allergy, and health history from parents and about each of their children under 18 years of age. Children were stratified into two groups by allergy status (yes/no), and associations between each variable and the odds of allergies were tested using univariable and multivariable mixed logistic regression models.

RESULTS

Of the 563 children in the study, 237 were reported to have allergies whereas 326 did not. Age, residential community, household income, mode of conception, paternal age at conception, biological parental allergy status, and history of asthma and eczema were significantly associated with allergies in univariable analysis. Multivariable analysis revealed household income ($50 k to $99 k vs ≥ $200 k adj OR = 2.72, 95% CI 1.11, 6.65), biological parental allergies (mother-adj OR 2.74, 95% CI 1.59, 4.72, father-adj OR 2.06, 95% CI 1.24, 3.41) and each additional year of age of children (adj OR 1.17, CI 1.10, 1.24) were significantly associated with odds of allergies in children.

CONCLUSION

Although the exploratory nature of this convenience, snowballing sample limited the generalizability of the findings, initial observations warrant further investigation and validation in a larger more diverse population.

Changing trends in the prevalence of childhood asthma over 40 years in Greece

BACKGROUND

A series of repeated questionnaire surveys among 8- to 9-year-old school children in the city of Patras, Greece, demonstrated a continuous rise in the prevalence of wheeze/asthma from 1978 to 2003, with a plateau between 2003 and 2008. We further investigated wheeze/asthma trends within the same environment over the last decade.

METHODS

Two follow-up surveys were conducted in 2013 (N = 2554) and 2018 (N = 2648). Physician-diagnosed wheeze and asthma were analyzed in relation to their occurrence (recent-onset: within the last 2 years; noncurrent: before 2 years; persistent: both prior and within the last 2 years). In 2018, spirometry was also performed in participants reporting symptoms and in a sample of healthy controls.

RESULTS

The prevalence of current wheeze/asthma declined from 6.9% in 2008% to 5.2% in 2013% and 4.3% in 2018. The persistent and noncurrent wheeze/asthma groups followed this overall trend (P-for-trend <0.001), while the prevalence of recent-onset wheeze/asthma remained unchanged (P-for-trend >0.05). Persistent and noncurrent wheezers were also more frequently diagnosed with asthma, in contrast to those with recent-onset wheeze. The FEV₁ z-score was less than -1 in 32.1% of children with recent-onset and in 22.4% of those with persistent wheeze/asthma; both rates were higher than those of the Noncurrent wheeze/asthma group (7.1%; p < .05) and of healthy controls (3.5%; p < .001).

CONCLUSIONS

The prevalence of childhood wheeze/asthma has declined significantly during the last decade in Greece. The reversing trend may in part be attributed to changing asthma perceptions among physicians and/or parents, especially in the case of younger children with troublesome respiratory symptoms.

Changes in the relationship between asthma and associated risk factors over fifty years

BACKGROUND

Childhood asthma is a common condition whose prevalence is changing. We hypothesized that the relationship between asthma and associated risk factors has changed over a 50-year period.

METHODS

An ecological study design was used. Children aged 8-13 attending schools in Aberdeen city were surveyed on seven occasions between 1964 and 2014. The following were determined: history of asthma, history of eczema, parental smoking, parental asthma, sex and socio-economic status. Analysis was by a structural change model with two knots. The outcome reported was the change in odds ratio between asthma and a given risk factor during a given period.

RESULTS

There were 23,241 questionnaires distributed and 17,439 returned (75%). The odds ratio (OR) for a child with asthma to have eczema increased between 1989 and 1999 by 1.031 [95% CI 1.028, 1.035] and by 1.042 between 2004 and 2014 [1.038, 1.047]. The OR for a child with asthma to have a parent who smoked rose by 1.032 [1.028, 1.036] between 1989 and 1999 and by 1.043 [1.038, 1.047] between 2004 and 2014), and to have a parent with asthma (1.027 [1.022, 1.031] for 1994-99 and 1.042 [1.037, 1.048] for 2004-2014). The OR for a child with asthma being male, but not and being from the most deprived communities, rose between 1989-1999 and 2004-2014.

CONCLUSIONS

The relationship between asthma prevalence and particular risk factors changed over the 50-year period of study, and this might reflect changes in children's environment and/or susceptibility.

Can general practice computer data be of use in assessing asthma service delivery and needs?

Objectives: To investigate the potential of general practice computer data in assessing asthma service delivery and need. To compare the epidemiology of coded asthmatics and those receiving asthma drugs with recognized patterns for asthma. To estimate asthma prevalence, preventer and reliever drug need and its possible cost in east London. Design: Descriptive study using asthma computer audits undertaken in June 1995 in five general practices selected for their interest in asthma.

Helicobacter pylori infection and asthma: Is there a direct or an inverse association? A meta-analysis

AIM: To analyze the consistency of a potential involvement of the bacterium infection in the asthma disease.

METHODS: A systematic literature search of the terms “Helicobacter pylori” (H. pylori) associated to “asthma” using PubMed, Scopus and the Cochrane Library Central was performed. Reference lists from published articles were also employed. Titles of these publications and their abstracts were scanned in order to eliminate duplicates and irrelevant articles. The criteria of inclusion of the studies were: Original studies; the H. pylori diagnostic method has been declared; all ranges of age have been included in our study; a definitive diagnosis of asthma has been reported.

RESULTS: We selected 14 articles in which the association between the two conditions was addressed. In 7 studies the prevalence of H. pylori infection in the asthma population and in the control population was made explicit. There was heterogeneity between the studies (Cohran’s Q = 0.02). The H. pylori infection in the asthma population resulted 33.6% (518 of 1542), while in the control population resulted 37.6% (2746 of 7310) (relative risk of H. pylori infection in the asthma population = 0.87, 95%CI: 0.72-1.05, P = 0.015, random effects model). Instead, considering the more virulent strains, the majority of studies showed an inverse relationship between the prevalence of H. pylori infection and asthma.

CONCLUSION: In our meta-analysis the prevalence of H. pylori infection in the asthma population resulted not statistically significant lower than in control population (P = 0.15). Instead, considering the more virulent strains, the majority of studies showed an inverse relationship between the prevalence of H. pylori infection and asthma.

Volatile organic compounds and risk of asthma and allergy: a systematic review

Volatile organic compounds (VOCs) are ubiquitous domestic pollutants. Their role in asthma/allergy development and exacerbations is uncertain. This systematic review investigated whether domestic VOC exposure increases the risk of developing and/or exacerbating asthma and allergic disorders. We systematically searched 11 databases and three trial repositories, and contacted an international panel of experts to identify published and unpublished experimental and epidemiological studies. 8455 potentially relevant studies were identified; 852 papers were removed after de-duplication, leaving 7603 unique papers that were screened. Of these, 278 were reviewed in detail and 53 satisfied the inclusion criteria. Critical appraisal of the included studies indicated an overall lack of high-quality evidence and substantial risk of bias in this body of knowledge. Aromatics (i.e. benzenes, toluenes and xylenes) and formaldehyde were the main VOC classes studied, both in relation to the development and exacerbations of asthma and allergy. Approximately equal numbers of studies reported that exposure increased risks and that exposure was not associated with any detrimental effects. The available evidence implicating domestic VOC exposure in the risk of developing and/or exacerbating asthma and allergy is of poor quality and inconsistent. Prospective, preferably experimental studies, investigating the impact of reducing/eliminating exposure to VOC, are now needed in order to generate a more definitive evidence base to inform policy and clinical deliberations in relation to the management of the now substantial sections of the population who are either at risk of developing asthma/allergy or living with established disease.

Epidemiology of Respiratory Allergies and Asthma

Asthma has puzzled and confused physicians from the time of Hippocrates to the present day. The word “asthma” comes from a Greek word meaning “panting” (Keeney 1964), but reference to asthma can also be found in ancient Egyptian, Hebrew, and Indian medical writings (Ellul-Micallef 1976; Unger and Harris 1974). There were clear observations of patients experiencing attacks of asthma in the second century and evidence of disordered anatomy in the lung as far back as the seventeenth century (Dring et al. 1689).

Fifty years of pediatric asthma in developed countries: how reliable are the basic data sources?

Given the difficulties in diagnosing, or even defining, asthma in children, claims of a pediatric asthma epidemic in Canada and other developed countries are accepted with surprisingly little critical examination. We reviewed a broad range of data sources to understand how the epidemic evolved during the last 50 years and also to assess the reliability of the conclusions drawn from that data. We obtained Canadian National and Provincial data from Statistics Canada National Population Health Survey, and the British Columbia Ministry of Health respiratory database. International data were obtained by extensive review of pediatric asthma epidemiological surveys published during the last 50 years. In many developed countries, there have been three separate epidemics involving different aspects of pediatric asthma during the last 50 years: a double peaked mortality epidemic (1960s and 1980s), a hospital admission epidemic (peaked around 1990) and a steadily growing epidemic of children who report asthmatic symptoms on questionnaires. Canadian pediatric rates for asthma mortality (1-2/million/year) and hospital admission (1-2/thousand/year) are low and have fallen for the last 20 years. Rates based on questionnaire studies are high (10-15/hundred) and rose steadily over the same period. Objective reductions in asthma deaths and hospital admission likely reflect improved education and treatment programmes. Current claims of an epidemic based largely on subjective self-reported symptoms require more careful analysis. The possibility that symptom misperception, disease fashions, and poor recall, may be part of the explanation for the current high levels of self-reported symptoms deserves more attention.

Importance of allergy in asthma: an epidemiologic perspective

There has been a global epidemic of asthma during the past half-century. More recently, the prevalence has leveled off or declined in many Western countries, whereas the prevalence in less affluent nations is still increasing. The reasons for this and the different geographical patterns of asthma prevalence remain unclear. This paper provides an epidemiologic perspective on whether allergen exposure and allergies can explain these trends. In particular, the paper discusses 1) geographical and temporal trends in asthma and the role of allergens and allergy, 2) the importance of nonallergic mechanisms, 3) nonallergenic exposures that may modify the risk of allergies and asthma, and 4) new and emerging risk and protective factors. Although allergy and asthma are closely related, allergen exposure and allergy alone cannot explain current time trends and geographical patterns of asthma. Population-based studies focusing on recently identified risk and protective factors may provide further insight.

Sex-specific trends in prevalence of childhood asthma over 30 years in Patras, Greece

AIM

 According to four surveys conducted during 1978-2003, the prevalence of childhood asthma and wheezing has risen in the city of Patras, Greece, albeit at a decelerating rate. We examined sex-specific wheeze and asthma prevalence in the same urban environment in 2008.

METHODS

A cross-sectional parental questionnaire survey was performed in 2008 among third and fourth grade schoolchildren (8-9 year old), which was identical to previously conducted surveys in 1978 (n = 3003), 1991 (n = 2417), 1998 (n = 3076) and 2003 (n = 2725).

RESULTS

The prevalence of current wheeze and asthma in 1978, 1991, 1998, 2003 and 2008 (n = 2688) was 1.5%, 4.6%, 6.0%, 6.9% and 6.9%, respectively (p for trend <0.001). Respective values for lifetime (ever had) wheeze and asthma in the 1991-2008 surveys were 8.0%, 9.6%, 12.4% and 12.6% (p for trend <0.001). The male:female ratio of current and lifetime wheeze and asthma increased during the 30-year surveillance period (p for trend <0.001). Irrespective of sex, diagnosed asthma declined among current wheezers by 17% (p < 0.001), but not among non-current ones (6.7%, p = 0.16) during 2003-2008.

CONCLUSIONS

Childhood wheeze and asthma have reached a plateau in an urban environment in Greece, while the male:female ratio increased. Asthma diagnosis declined among schoolage but not preschool wheezers during 2003-2008.

S, DUMITRESCU D, MARSHALL M, MIRESTEAN I, MURESAN M, IACOB D, FARCAU M, ICHIM GE, NANULESCU MV. Epidemiological survey 6 years apart: increased prevalence of asthma and other allergic diseases in schoolchildren aged 13-14 years in cluj-napoca, romania (based on isaac questionnaire)

BACKGROUND

The prevalence of asthma and allergy has increased during recent decades.

OBJECTIVE

We investigate the prevalence of asthma and other allergic diseases in children aged 13-14 years and we evaluate the trend of prevalence after an interval of 6 years.

MATERIAL AND METHODS

We used a core questionnaire designed by the International Study of Asthma and Allergy in Children. In 1991, the questionnaire was administered to 2,866 children from a Romanian city and during 2001 to 1,657 children from the same area.

RESULTS

The prevalence of asthma increased from 3.3% in 1995 to 5.5% in 2001 (p<0.001). In 1995, 4.3% of children reported asthma-related symptoms, significantly fewer than the percentage 6 years later (13.6%; p<0.00001). Similar results were obtained with regard to allergic rhinitis (13.6% versus 20%; p<0.00001) and eczema (11.5% versus 16.2%; p=0.00015). As far as gender differences are concerned, in the first stage of study all three allergic disorders were found to occur more frequently in females. In the study undertaken in 2001, females proved to have a higher prevalence of asthma (p=0.226), but a lower prevalence for allergic rhinitis (p=0.121) and eczema (p=0.064).

CONCLUSIONS

The prevalence of asthma and allergy increased significantly during the past 6 years.

Changes in the prevalence of asthma, eczema and hay fever in pre-pubertal children: a 40-year perspective

Surveys of primary schools children in Aberdeen carried out in 1964, 1989, 1994 and 1999 suggested a slowing of the increase in parent-reported wheeze between 1994 and 1999. To assess whether this pattern had continued, questionnaires were distributed to 5712 children aged 7-12 years in the same schools in 2004. A total of 3271 (57.3%) completed questionnaires were returned. As in earlier surveys the results were divided into those for younger children (school years 3-4; age 7-9 years) and older children (school years 5-7; age 9-12 years). Compared with 1999, the 2004 results showed a decrease in the proportion of children with wheeze in the last 3 years from 30.1% to 23.3% (P < 0.001) in the younger group and from 27.6% to 25.1% (P = 0.052) in the older group. There was no significant change in the lifetime prevalence of asthma in either the younger or the older group, but the lifetime prevalence of eczema and hay fever increased by around 10% in both the younger and older groups (all P < 0.001). The differences in the time trends for the different conditions suggest that the causal factors for wheeze and asthma differ from those for other allergic diseases of childhood.

Undertreatment of allergy: exploring the utility of sublingual immunotherapy

Allergic syndromes are highly prevalent and are comprised of a wide variety of clinical problems, including rhinitis, conjunctivitis, atopic dermatitis and urticaria, asthma, and food allergies. Numerous studies have shown that allergic syndromes are both underdiagnosed and undertreated. This is related to many factors, including trivialization of allergic conditions by physicians and patients, failure to adhere to diagnostic and treatment guidelines, and dissatisfaction with conventional pharmacologic treatments. Immunotherapy involves the administration of allergen extracts in an attempt to induce immunologic tolerance and has been used for the treatment of allergic syndromes and the prevention of long-term complications. Conventional subcutaneous immunotherapy is effective but is also associated with a risk of serious adverse events, requires administration by a trained health care professional, and is contraindicated in certain populations. By contrast, sublingual immunotherapy has been used extensively in Europe and possesses most of the benefits of subcutaneous immunotherapy along with increased safety, tolerability, and convenience. This narrative review explores data from selected clinical studies and concludes that sublingual immunotherapy may be well suited to fill the gap posed by the undertreatment of allergic syndromes in the United States.

Asthma drugs counter-regulate interleukin-8 release stimulated by sodium sulfite in an A549 cell line

BACKGROUND

Clinical manifestations suggest that air pollution may induce deterioration of respiratory health. Some air pollutants, including sulfite, may play a role in the exacerbation of asthma. Sulfites are formed at bronchial mucosa from inhaled sulfur dioxide. It has been previously reported that sodium sulfite (Na(2)SO(3)) has pro-inflammatory properties and enhances neutrophil adhesion to A549 cells. Interleukin-8 (IL-8) plays a critical role in attracting inflammatory cells and is an excellent marker of pulmonary cell activation. To date, there have not been any reports on the effect of asthma drugs on the suppression of IL-8 production induced by sulfite in A549 cells or the involvement of specific signal transduction pathways. Thus, our study assessed the effects of salmeterol, fluticasone, and montelukast on human epithelial lung cell inflammation as well as the inhibitors in different signal transduction pathways.

METHODS

A549 human lung epithelial cells were cultured under the following conditions: (1) treated with sodium sulfite (0, 100, 500, 1000, 2500 uM) for 16 hours; (2) cultured for 1 hour in the presence of SB203580, PD98059, SP600125, or wedeloactone, then co-incubated with sodium sulfite for another 16 hours; (3) cultured for 4 hours in the presence of salmeterol, fluticasone, or montelukast, then stimulated with sodium sulfite at a concentration of 1000 uM for 16 hours. We collected the supernatants from the above conditions and performed enzyme-linked immunosorbent assay (ELISA) to measure the IL-8 concentration.

RESULTS

IL-8 production increased after treatment with sodium sulfite at 1000 to 2500 uM (p <or= 0.001). SB203580, PD98059, and wedeloactone decreased IL-8 production stimulated by Na(2)SO(3) (p < 0.01). Salmeterol, fluticasone, and montelukast significantly suppressed IL-8 secretion from sodium sulfite-stimulated A549 cells (p < 0.01).

CONCLUSIONS

Sodium sulfite has pro-inflammatory properties in vitro and can induce potent chemotactic factor IL-8 production. Possible signal transduction pathways required for IL-8 gene expression following exposure to sulfite are the NF-kappa B, ERK, and p-38-dependent pathways. Salmeterol, fluticasone, and montelukast all have inhibitory effects on sodium sulfite-induced IL-8 production in A549 cells.

Serum polycyclic aromatic hydrocarbons among children with and without asthma: correlation to environmental and dietary factors

BACKGROUND

Children from low-income families may be subject to high exposures to polycyclic aromatic hydrocarbons (PAH) which can lead to respiratory disorders. This study aims to establish methods for assessing total PAH exposure of asthmatic and non-asthmatic children from low-income families; to estimate serum PAH concentrations of these children, and to estimate the relative importance of the environmental pathways for PAH exposure.

MATERIALS AND METHODS

A total of 75 (61 asthmatic, 14 non-asthmatic) Saudi children 15 years old and below were included to participate in this cross-sectional study. Each participant answered a generalized questionnaire with dietary questions. Serum PAH were measured using HPLC with UV detection.

RESULTS

Serum naphthalene and pyrene were significantly elevated among asthmatic children (p-values = 0.007 and 0.01, respectively). Serum acenaphthylene, fluorine and 1,2-benzanthracene, on the other hand, were significantly higher among non-asthmatics (p-values = 0.001, 0.04 and 0.03, respectively). There was a significant correlation between the presence of a smoker in the family and serum concentrations of carbazole, pyrene, 1,2-benzanthracene and benzacephenanthrylene (R = 0.37, 0.45, 0.43, 0.33; p-values = 0.01, 0.0002, 0.003 and 0.025, respectively). Significant correlations were elicited between daily meat intake and serum levels of acenaphthylene, benzopyrene and 1,2-benzanthracene (R = 0.27, 0.27, 0.33; p-values = 0.02 and < 0.001, respectively).

CONCLUSION

Among the children, serum PAH were significantly correlated to meat intake as well as presence of smokers at home. Public health awareness should be enhanced by educating parents to take certain precautions at home, such as preventing indoor smoking and reducing the intake of grilled and smoked meat by children so as to decrease their exposure to carcinogenic PAH.

Allergy and risk of childhood leukaemia: results from the UKCCS

We investigated the relationship between childhood leukaemia and preceding history of allergy. A nationwide case-control study of childhood cancers was conducted in the United Kingdom with population-based sampling of cases (n = 839) and controls (n = 1,337), matched on age, sex and region of residence. Information about clinically diagnosed allergies was obtained from primary care records. More than a third of subjects had at least one allergy diagnosed prior to leukaemia diagnosis (cases) or pseudo-diagnosis (controls). For both total acute lymphoblastic leukaemia (ALL) and common-ALL/precursor B-cell ALL (c-ALL), a history of eczema was associated with a 30% significant reduction in risk: the odds ratios (OR) and 95% confidence intervals (CI) were 0.70 (0.51-0.97) and 0.68 (0.48-0.98), respectively. Similar associations were observed for hayfever (OR = 0.47; 95% CI: 0.26-0.85 and OR = 0.62; 95% CI: 0.33-1.16 for ALL and c-ALL, respectively). No such patterns were seen either for asthma and ALL, or for any allergy and acute myeloid leukaemia. A comparative analysis of primary care records with parents recall of allergy revealed only moderate agreement with contemporaneous clinical diagnoses for both cases and controls--confirming the unreliability of parental report at interview. Our finding of a reciprocal relationship between allergy and ALL in children is compatible with the hypothesis that a dysregulated immune response is a critical determinant of childhood ALL.

Maternal influence in the transmission of asthma susceptibility

Asthma is one of the most common chronic diseases in children, with increasing morbidity and mortality. A genetic predisposition and exposure to allergens have been implicated as major risk factors for the development of asthma. However, increasing evidence indicates that the mother plays a crucial role in mediating the development of fetal-infant immune responses to inhaled allergens. The exact nature and mechanism of this maternal influence and how it might be associated with the development of allergic sensitization and asthma are not clear. Under normal conditions, the maternal environment during pregnancy promotes an initial Th2 skewed immune response in the offspring which transitions to a nonallergic Th1 type response after birth. However, the allergic mother's influence may delay the normal transition to a nonallergic immune response to inhaled allergens in her children, thus increasing the risk for the development of allergic sensitization and/or asthma. Understanding the underlying mechanisms by which the maternal immune environment can influence the development of the fetal-infant immune response to inhaled allergens may lead to identifying new targets for the prevention of allergic sensitization and asthma.

Prevalence of asthma among schoolchildren in Patras, Greece: four questionnaire surveys during 1978-2003

BACKGROUND

The prevalence of asthma and wheezing has risen during the past four decades. Recent reports suggest that the "asthma epidemic" has reached a plateau.

OBJECTIVE

To examine further trends in the prevalence of childhood diagnosed asthma and wheezing in an urban environment in Greece.

METHODS

A population-based cross-sectional parental questionnaire survey was repeated among third-grade and fourth-grade school children (8-10 years) of public primary schools in 2003 in the city of Patras, Greece, by using methods identical to that of surveys conducted in 1978 (completed questionnaires, n = 3003), 1991 (n = 2417) and 1998 (n = 3076).

RESULTS

2725 questionnaires were completed in the 2003 survey. The prevalence rates of current asthma and/or wheezing in 1978, 1991, 1998 and 2003 were 1.5%, 4.6%, 6% and 6.9%, respectively (p for trend <0.001). The lifetime prevalence of asthma and/or wheezing in the three more recent surveys was 8%, 9.6% and 12.4%, respectively (p for trend <0.001). The male:female ratios of current asthma and/or wheezing in the four surveys were 1.14:1, 1.15:1, 1.16:1 and 1.22:1, respectively. The proportion of those with wheezing diagnosed with asthma has increased during the study period, more so among non-current children with asthma.

CONCLUSIONS

Our findings show a continuous increase in the prevalence of asthma and wheezing among preadolescent children in Patras, Greece, over 25 years, albeit at a decelerating rate. There seems to be a true increase in wheezing, despite some diagnostic transfer, particularly among younger children. The male predominance of the disease has persisted in the population of this study.

Changing trends in sex specific prevalence rates for childhood asthma, eczema, and hay fever

Numerous surveys of school-aged children have shown increasing asthma prevalence with a less publicized but noticeable change in the male to female ratio. We sought to confirm this change in the sex ratio in four questionnaire-based surveys and investigate possible explanations. Identical questionnaire surveys were performed in 1989 (n=3,390), 1994 (n=4,047), 1999 (n=3,540) and 2004 (n=1,920) in school-children aged 9-11 years. Over these 15 years the male to female ratio (M:F) significantly narrowed for wheeze (1.34 to 0.98:1 P < 0.0002), for asthma (1.74 to 1.02:1 P < 0.0001), for eczema (1.42:1 to 0.81:1 P < 0.0001) and for hay fever (1.46 to 0.93:1 P < 0.0001). The diagnosis of asthma in children with wheeze was more commonly made in boys in 1989 relative risk RR 1.32 (1.12, 1.56), even in those with accompanying eczema and/or hay fever RR 1.20 (0.99, 1.45). By 2004 this sex bias in diagnosis was no longer present, RR 1.01 (0.91, 1.12) for wheeze and 1.02 (0.85, 1.21) for those with wheeze and eczema and/or hay fever. From 1989 to 2004 no significant difference in sex distribution changes between older and younger children occurred, making secular trends in the onset of puberty in females an unlikely contributory factor. The disappearance of the bias to diagnose asthma in symptomatic males but not in females may be partly responsible for the narrowing of the sex ratio, but other factors such as those enhancing the expression of asthma and atopy in females may also be implicated.

What are we learning from genetic cohort studies?

Although genetic component of asthma has been well recognised, genetics alone cannot explain the rise in asthma prevalence. This increase is likely a consequence of environmental factors increasing the risk in genetically susceptible individuals. As wheezing illness usually begins within months of birth, prospective birth cohorts with detailed measures of environmental exposures and objective measures of disease are essential to study gene-environment interactions in the development of different wheeze phenotypes. Such studies will enable identification of children at increased risk of disease because of a genetic predisposition when exposed to a particular environmental factor. Tailor-made evidence-based strategies for prevention of asthma and atopic sensitization applicable to individuals at risk (rather than the whole population) will then be developed to reduce the risk of asthma and allergy development.

Influence of dog ownership and high endotoxin on wheezing and atopy during infancy

BACKGROUND

Increased exposure to microbial products early in life may protect from development of atopic disorders in childhood. Few studies have examined the relationship of endotoxin exposure and pet ownership on atopy and wheezing during infancy.

OBJECTIVE

Evaluate relationships among high endotoxin exposure, pet ownership, atopy, and wheezing in high-risk infants.

METHODS

Infants (n = 532; mean age, 12.5 +/- 0.8 months) with at least 1 parent with confirmed atopy were recruited. A complete medical history and skin prick testing to foods and aeroallergens were performed at age 1 year. House dust samples were analyzed for endotoxin.

RESULTS

Prevalences of wheezing were not independently associated with dog or cat ownership or endotoxin levels. Percutaneous reactivity to at least 1 allergen was observed in 28.6% of infants. Univariate analyses showed significant associations of any wheezing, recurrent wheezing, and recurrent wheezing with an event with daycare attendance, number of siblings, respiratory infections, maternal smoking, and history of parental asthma. Logistic regression adjusting for the latter variables showed that recurrent wheezing (odds ratio, 0.4; 95% CI, 0.1-0.9) as well as 2 other wheeze outcomes were significantly reduced in homes with high endotoxin exposure in the presence of 2 or more dogs.

CONCLUSION

Pet ownership or endotoxin did not independently modify aeroallergen sensitization or wheezing during infancy. However, high endotoxin exposure in the presence of multiple dogs was associated with reduced wheezing in infants.

CLINICAL IMPLICATIONS

A home environment with many dogs and high levels of endotoxin may be conducive to reduced wheezing in infancy.

Trends in childhood disease

Child mortality has declined remarkably during the last decades. While neonatal disorders, diarrhoea, pneumonia, and malaria as well as being underweight account for most of the child deaths worldwide, children's health discussions in Europe and the USA focus on other issues such as asthma, neurodevelopmental disorders, male genital malformations, and childhood cancer. There is clear evidence of increasing rates of asthma in various countries during the last decades, although rates in some countries may now have stabilised or even decline as recent UK data indicate. Although an increase in the frequency of neurodevelopmental disorders such as autism and attention deficit disorder has frequently been discussed, the limited data in this field does not justify such a conclusion. While geographic heterogeneity regarding reproductive outcomes is apparent, global trends have not been identified. Interpretation of the available information on asthma, neurodevelopmental disorders and reproductive outcomes is hampered by inconstant diagnostic criteria over place and time and the lack of good and comprehensive population-based surveillance data, which makes it impossible to ascertain trends in actual disease frequency. Data indicate that developed countries have a gradually increasing incidence in leukaemia with a corresponding drop in the incidence of lymphoma. Increases in brain tumour frequency may be related to the development and wide application of new diagnostic capabilities, rather than a true change in the incidence of malignant disease. With a better prognosis for childhood cancer survival, secondary cancers following chemotherapy appear to be increasing. A wide range of environmental factors is thought to have an impact on children's health. These factors include nutrition (protein, vitamins, antioxidants), lifestyle and behaviour choices such as tobacco and alcohol use, parental health, socio-economic status, choice of living environment (urban versus rural, etc.), and parent-sibling behaviour. From the available data, no general conclusions on the contribution of specific chemicals can be drawn.

The childhood asthma epidemic

A case of delayed rather than mistaken diagnosis

A comparison of virus-associated and multi-trigger wheeze in school children

To examine differences between virus-associated wheeze and wheeze associated with other triggers (multi-trigger wheeze) in elementary school children, we performed a cross-sectional school-based questionnaire study of 5,998 children mainly 7 to 12 years of age, with outliers 6 and 13 years of age. Using parent-completed questionnaires, we identified 522 children who wheezed only during upper respiratory tract infections (virus-associated wheeze), 1,186 children who wheezed on other occasions (multi-trigger wheeze), and 4,290 children with no wheeze. In comparison with children who had multi-trigger wheeze, children with virus-associated wheeze were more likely to be male, to be younger, and to have less frequent wheezy episodes. They were less likely to have night cough, shortness of breath or chest tightness, to have a personal or parental history of atopic disorders, to have a diagnosis of asthma, or to be receiving asthma treatment. Both types of wheeze were associated with social deprivation, a relationship that persisted after controlling for family smoking. Virus-associated wheeze is a common but diminishing problem in this age group, and the differences between virus-associated wheeze and multi-trigger wheeze already noted in pre-school children persist in this older age group.

Prevalence of asthma, eczema and allergic rhinitis: two surveys, 6 years apart, in Kota Bharu, Malaysia

OBJECTIVE

This study was undertaken to determine the prevalence of asthma, eczema, and allergic rhinitis in school children in Kota Bharu, Malaysia, and in so doing to determine the differences in symptom prevalence rates of asthma, and atopic diseases in Kota Bharu school children between 1995 and 2001.

METHODOLOGY

In two studies (1995 and 2001), year one primary school (PS) pupils (6-7 years old) and secondary school (SS) year two pupils (13-14 years old) were randomly selected from the district of Kota Bharu, Kelantan, Malaysia. In 1995, 3939 PS children and 3116 SS children participated, and in 2001 3157 PS children and 3004 SS children participated. The Phase I International Study of Asthma and Allergies in Childhood prevalence written questionnaire and video questionnaire (only shown to SS children) were used in both studies.

RESULTS

The written questionnaire showed no significant changes in the prevalence (1995, 2001) of ever wheeze (8.3%, 6.9%P = 0.06), current wheeze (5.4%, 4.3%P = 0.08), exercise-induced wheeze (EIW; 3.9%, 3.7%P = 0.63), and rhinoconjunctivitis (4.6%, 5%P = 0.42) among PS children. The prevalence of flexural itchy rash increased from 14% to 17.6% (P = 0.004) and night cough decreased from 20.4% to 17.5% (P = 0.005). There were also no significant changes in these symptoms among SS children (1995, 2001): ever wheeze (10.7%, 12%P = 0.37), current wheeze (6.8%, 5.7%P = 0.20), EIW (9.9%, 11.6%P = 0.28), night cough (21.6%, 24%P = 0.39), rhinoconjunctivitis (11%, 15%P = 0.11), and flexural itchy rash (12%, 13%P = 0.11). The video questionnaire showed no significant changes in the prevalence of symptoms in the previous 12 months (1995 vs 2001) for wheeze at rest (3.8%, 2.8%P = 0.12), EIW (6.9%, 8.8%P = 0.32), waking with wheeze (1.7%, 1.7%P = 1.0), and severe wheeze (2.1%, 3%P = 0.12). Night cough in the previous 12 months increased significantly from 5.1% to 8.3% (P = 0.007).

CONCLUSION

Although asthma and atopic disorders are common in this country, the results revealed no major changes in the prevalence rates of these diseases over a period of 6 years.

Indoor environment and respiratory symptoms in children living in the Dutch-German borderland

OBJECTIVE

To investigate the relation between indoor environmental risk factors and respiratory symptoms in 7-8-year-old children living in the Dutch-German borderland.

METHODS

A nested case-control study was conducted among children participating in a large longitudinal study on respiratory health. Parents of all 781 children with respiratory complaints and an equal number of randomly selected controls were asked to complete a questionnaire, including questions on indoor environment.

RESULTS

The parents of 1191 children (76.2%) participated. Past exposure to environmental (OR = 2.73, 95% CI 1.14-6.67) as well as in utero exposure (OR = 2.28, 95% CI 1.15-4.53) to tobacco smoke, use of an unvented geyser for water heating (OR = 3.01, 95% CI 1.21-7.56), long-term exposure to dampness (OR = 2.98, 95% CI 1.10-8.28) or pets (OR = 2.18, 95% CI 1.39-3.42) increased the risk of asthmatic symptoms in 7-8-year-old children. A middle or low socio-economic status also increased the risk of asthmatic symptoms. An inverse association with asthmatic symptoms was seen for wall-to-wall carpeting (OR = 0.57, 95% CI 0.33-0.95) and insulation measures (OR = 0.46, 95% CI 0.25-0.83). Except for the presence of an unvented geyser, these environmental risk factors also presented a risk for coughing symptoms in children.

CONCLUSION

This study showed an increased risk of respiratory symptoms in children exposed to several indoor environmental risk factors.

Trends in primary care consultations for asthma in Switzerland, 1989-2002

BACKGROUND

There is widespread debate about trends in the occurrence of asthma in industrialized countries. This study was conducted to investigate time trends in consultations for asthma in primary care in Switzerland.

METHODS

Prospective observational study from 1989 to 2002 within the Swiss Sentinel Surveillance Network; a primary care surveillance system. We used time series analysis and non-parametric smoothing methods to investigate long-term and short-term trends in rates of asthma episodes per 1000 consultations. From 1994 to 2002 we compared rates of first episodes with all subsequent consultations for asthma.

RESULTS

Overall consultation rates for asthma per 1000 primary care consultations increased from 1989 to 1994 then stabilized and have declined since 2000. Long-term trends showed a small decline in first consultations for asthma from an average of 0.78 (95% credibility intervals (CI) 0.74-0.81) in 1999 to 0.62 (95% CI 0.55-0.69) per 1000 consultations in 2002. Subsequent consultations for asthma have been declining since at least 1994, from an average of 1.5 (95% CI 1.40-1.61) per 1000 consultations in 1994 to 0.93 (95% CI 0.82-1.04) in 2002. In addition, the ratio of subsequent to first episodes of asthma fell in all age groups.

CONCLUSIONS

In Switzerland, primary care consultations for asthma, subsequent to the initial diagnosis, have been declining since 1994. This is more likely to be owing to an increase in the use of home medication than to a shift in care to hospital settings. The incidence of diagnosed asthma might also be decreasing.

Polymorphisms in a disintegrin and metalloprotease 33 (ADAM33) predict impaired early-life lung function

RATIONALE

Asthma commonly originates in early life in association with impaired lung function, which tracks to adulthood.

OBJECTIVES

Within the context of a prospective birth cohort study, we investigated the association between single nucleotide polymorphisms (SNPs) in a disintegrin and metalloprotease 33 (ADAM33) gene and early-life lung function.

METHODS

Children were genotyped for 17 SNPs in ADAM33. Lung function at age 3 (n = 285) and 5 years (n = 470) was assessed using plethysmographic measurement of specific airway resistance (sRaw). At age 5, we also measured FEV(1). SNPs were analyzed individually using logistic regression, followed by linkage disequilibrium mapping to identify the causal locus.

MAIN RESULTS

Carriers of the rare allele of F+1 SNP had reduced lung function at age 3 years (p = 0.003). When the recessive model was considered, four SNPs (F+1, S1, ST+5, V4) showed association with sRaw at age 5 years (p < 0.04). Using linkage disequilibrium mapping, we found evidence of a significant causal location between BC+1 and F1 SNPs, at the 5' end of the gene. Four SNPs were associated with lower FEV(1) (F+1, M+1, T1, and T2; p < or = 0.04). The risk of transient early wheezing more than doubled among children homozygous for the A allele of F+1 (odds ratio, 2.39; 95% confidence intervals, 1.18-4.86; p = 0.02), but there was no association between any SNP and allergic sensitization or physician-diagnosed asthma.

CONCLUSIONS

Polymorphisms in ADAM33 predict impaired early-life lung function. The functionally relevant polymorphism is likely to be at the 5' end of the gene.

Deprivation, smoking, and quality of life in asthma

AIMS

To explore associations of deprivation and smoking, with prevalence of asthma, wheeze, and quality of life.

METHODS

Survey, using International Study of Asthma and Allergies in Childhood (ISAAC) methodology, of children aged 13-14 years attending Scottish schools previously surveyed in 1995.

RESULTS

4665/5247 (89%) pupils completed questionnaires. 3656/4665 (78.4%) had missed school for any reason in the last 12 months, 587 (12.6%) because of asthma or wheeze. Compared to children with 1-3 wheeze attacks per year, those with >12 attacks in the last year were more likely to have missed school, twice as likely to have missed physical education in the last month, to report interference with home activities, or to have visited accident and emergency departments, and three times more likely to have been hospitalised. Deprivation was not independently associated with self-reported asthma or wheeze, but was associated with school absence, either for any reason or specifically for asthma or wheeze, but not with use of services such as accident and emergency visits, doctor visits, or hospital admissions. Active smoking was associated with wheezy symptoms, and active and passive smoking with use of medical services. These associations were independent of wheeze severity, treatment taken, and other associated atopic conditions. Smoking also had an impact on school absence and home and school activities.

CONCLUSIONS

Deprivation does not affect the prevalence of asthma or wheeze. Exposure to cigarette smoke was associated with the increased use of services. Deprivation and smoking have independent adverse effects on the quality of life in subjects with asthma or wheeze.

Frequent use of chemical household products is associated with persistent wheezing in pre-school age children

BACKGROUND

In the UK and other developed countries the prevalence of asthma symptoms has increased in recent years. This is likely to be the result of increased exposure to environmental factors. A study was undertaken to investigate the association between maternal use of chemical based products in the prenatal period and patterns of wheeze in early childhood.

METHODS

In the population based Avon Longitudinal Study of Parents and Children (ALSPAC), the frequency of use of 11 chemical based domestic products was determined from questionnaires completed by women during pregnancy and a total chemical burden (TCB) score was derived. Four mutually exclusive wheezing patterns were defined for the period from birth to 42 months based on parental questionnaire responses (never wheezed, transient early wheeze, persistent wheeze, and late onset wheeze). Multinomial logistic regression models were used to assess the relationship between these wheezing outcomes and TCB exposure while accounting for numerous potential confounding variables. Complete data for analysis was available for 7019 of 13, 971 (50%) children.

RESULTS

The mean (SD) TCB score was 9.4 (4.1), range 0-30. Increased use of domestic chemical based products was associated with persistent wheezing during early childhood (adjusted odds ratio (OR) per unit increase of TCB 1.06 (95% confidence interval (CI) 1.03 to 1.09)) but not with transient early wheeze or late onset wheeze. Children whose mothers had high TCB scores (>90th centile) were more than twice as likely to wheeze persistently throughout early childhood than children whose mothers had a low TCB score (<10th centile) (adjusted OR 2.3 (95% CI 1.2 to 4.4)).

CONCLUSION

These findings suggest that frequent use of chemical based products in the prenatal period is associated with persistent wheezing in young children. Follow up of this cohort is underway to determine whether TCB is associated with wheezing, asthma, and atopy at later stages in childhood.

Childhood asthma hospitalization risk after cesarean delivery in former term and premature infants

BACKGROUND

Cesarean delivery modifies infant gut bacterial flora composition, which may result in hindered tolerance to allergenic substances, thereby increasing the risk of asthma in accordance with the hygiene hypothesis. Results of previous studies regarding an association between birth route and asthma are conflicting, and these studies have not evaluated some potential confounding effects, including prematurity and maternal asthma.

OBJECTIVE

To determine whether cesarean delivery in full-term and premature infants increases the risk of subsequent childhood asthma hospitalization.

METHODS

We conducted a case-control study using the Washington State Birth Events Record Database linked to statewide hospitalization data. The study included 2,028 children hospitalized for asthma (cases) and 8,292 age-matched controls.

RESULTS

Cesarean delivery was modestly associated with an increased risk of asthma hospitalization (odds ratio [OR], 1.20; 95% confidence interval [CI], 1.04-1.39). However, when analyzed separately, there was an association between cesarean delivery and asthma hospitalization in premature infants (OR, 1.90; 95% CI, 1.09-3.02) but not in full-term infants (OR, 1.15; 95% CI, 0.97-1.34).

CONCLUSIONS

Cesarean delivery was associated with subsequent asthma hospitalization only in premature infants. Because mothers with asthma are reported to have increased rates of cesarean delivery and premature delivery, other factors in addition to the hygiene hypothesis, including genetic and in utero influences associated with maternal asthma, may contribute to the increased risk of asthma in premature infants.

Development of a questionnaire weighted scoring system to target diagnostic examinations for asthma in adults: a modelling study

Background

Identification and treatment of unrecognised asthmatics in the community is important for improving the health of the individual and minimising cost and quality of life burden. It is not practical to offer clinical diagnostic assessment to whole communities, and a simple tool such as a questionnaire is required to identify a smaller target group. Conventional questionnaire screening methods which separate individuals into positive and negative categories have resulted in large numbers of individuals requiring clinical assessment. This study has therefore developed and tested a weighted scoring system that prioritises those most urgently in need, based on their questionnaire responses.

Methods

A stratified random sample of adult respondents to a general practice postal questionnaire survey were categorised 'asthmatic' or 'non-asthmatic' according to three expert physicians' opinions. Based on this categorisation, logistic regression was used to derive weights reflecting the relative importance of each question in predicting asthma, allowing calculation of weighted scores reflecting likelihood of asthma. Respondents scoring higher than a chosen threshold would be offered diagnostic examination.

Results

Age and presence of wheeze were most influential (weight 3) and overall weighted scores ranged from -1 to 13. Positive predictive values (PPV) were estimated. For example, setting the threshold score at nine gave an estimated PPV for asthma diagnosis of 93.5%, a threshold score of seven corresponded to PPV 78.8%. PPV estimates were supported by examining 145 individuals from a new survey.

Conclusion

Weighted scoring of questionnaire responses provides a method for evaluating the priority level of an individual 'at a glance', minimising the resource wastage of examining false positives.

Antioxidant intake in pregnancy in relation to wheeze and eczema in the first two years of life

Two thousand women were recruited for a prospective investigation of the influence of maternal antioxidant intake in pregnancy on the development of asthma and eczema in children. A food frequency questionnaire was used to characterize diet during pregnancy and blood antioxidant levels were measured. Postal questionnaires were used to follow up the 1,924 singleton children born to the cohort at 6, 12, and 24 months of age. There were no associations between maternal antioxidant intake and wheezing symptoms and eczema in the children's first year. In the children's second year, maternal vitamin E intake during pregnancy was negatively associated with wheeze in the absence of a "cold" (p for trend 0.010) and, in children whose mothers were atopic, there was a negative association between maternal vitamin E intake and childhood eczema (p for trend 0.024). Maternal vitamin C intake during pregnancy was positively associated with "ever wheeze" and eczema during the children's second year. This study suggests that maternal dietary antioxidant intakes during pregnancy may modify the risks of developing wheeze and eczema during early childhood. Further follow up of the cohort will determine whether maternal diet during pregnancy is associated with asthma and atopic disease in later childhood.

Microorganisms and volatile organic compounds in airborne dust from damp residences

Airborne dust samples from damp (n = 9) and control (n = 9) residences were analyzed for microorganisms (molds and bacteria), bacterial markers (3-hydroxy fatty acids and muramic acid), and adsorbed volatile organic compounds (VOCs). The number of mold species was greater in the damp residences than in the controls (23 vs.18) and nine mold species were found only in damp residences. The levels of 3-hydroxy fatty acids and muramic acid correlated better in damp residences than in controls, indicating that damp conditions affect the bacterial flora of airborne dust. Identifications made by culture and microscopy of the major molds found, i.e. Aspergillus, Cladosporium, and Penicillum, coincided with the identification of VOCs known to be produced by these species. A number of additional VOCs irritating to the skin, eyes, or respiratory tract were also found. The results from this pilot study illustrate the diversity of microorganisms and VOCs present in the indoor environment and suggest that analysis of airborne dust may help to assess human exposure to microorganisms and chemical compounds.

Parental allergic status influences the risk of developing allergic sensitization and an asthmatic-like phenotype in canine offspring

Increasing evidence suggests that parental allergic status, especially that of the mother, may play a unique and important role in influencing the development of fetal infant immune responses to inhaled allergens, independently of genetic predisposition. We have developed an experimental model in dogs where the offspring from allergic parents, when exposed to inhaled allergen, develop allergic sensitization and an asthmatic phenotype, whereas the offspring from non-allergic parents do not. Offspring from ragweed-sensitized (two litters, n = 10) or non-sensitized (two litters, n = 11) Beagle dogs were exposed repeatedly, by inhalation, to ragweed or filtered air (negative control) beginning within 1 week after birth. Serum levels of total immunoglobulin (Ig)E, and ragweed-specific IgE and IgG, were measured at specific time-points up to 40 weeks after birth. Cell differentials in the bronchoalveolar lavage were determined on days 1 and 4 following ragweed instillation into the offspring's lungs at 26 weeks of age. Changes in pulmonary resistance following challenge with histamine and ragweed (five breaths) were measured at 40 weeks after birth. Offspring from sensitized parents exposed to ragweed developed elevated serum total IgE and ragweed-specific IgE and IgG, and showed an increased pulmonary resistance to histamine and ragweed, and increased numbers of eosinophils in bronchoalveolar lavage. In contrast, offspring from non-sensitized parents did not exhibit this immune response. These results suggest that parental allergic sensitivity is important in the development of allergic sensitization and an asthmatic phenotype in the offspring.

Wheezy bronchitis in childhood: a distinct clinical entity with lifelong significance?

BACKGROUND

Historically, clinicians have recognized the existence of the clinical syndrome of childhood wheezy bronchitis. In the late 1960s, children with this syndrome were relabeled as having asthma, and the term wheezy bronchitis was abandoned. In a 1989 study of a cohort that originally had been studied in 1964, we reported that those who had childhood wheezy bronchitis had as adults attained lung function similar to that of healthy control subjects and had less significant symptoms than did those who had experienced childhood asthma, in whom lung function was reduced. In this study, we reexamined these subjects 12 years later to determine whether the improved outcome of the wheezy bronchitis group had been maintained.

METHODS

In 2001, we followed up the 283 participants of the 1989 study, who were now aged 45 to 50 years. In interviews, respiratory symptoms and smoking status were assessed. Spirometry was measured.

RESULTS

One hundred seventy-seven subjects (63%) completed the study. After adjusting for age, height, gender, socioeconomic status, smoking status, and number of pack-years smoked, the current FEV(1) in the childhood asthma group (mean, 2.45 L; 95% confidence interval, 2.29 to 2.62) was significantly lower than the wheezy bronchitis group (2.78 L, 95% confidence interval, 2.64 to 2.91; p < 0.01) and the control group (2.96 L; 95% confidence interval, 2.83 to 3.1; p < 0.01). The difference between the wheezy bronchitis group and the control subjects was not significant (p = 0.06). Between 1989 and 2001, both the childhood wheezy bronchitis group (p < 0.01) and the childhood asthma group (p = 0.01) had greater declines in FEV(1) than did the control group (asthma group decline, - 0.75 L [95% confidence interval, - 0.66 to - 0.84]; wheezy bronchitis group decline, - 0.75 L [95% confidence interval, - 0.68 to - 0.83]; control group decline, - 0.59 L [95% confidence interval, - 0.52 to - 0.67]). In 2001, the asthma group had more symptoms than did the wheezy bronchitis group (p < 0.01), who were more symptomatic than the control group (p < 0.01).

CONCLUSION

Those with childhood wheezy bronchitis, having achieved normal lung function in earlier adulthood, now show a more rapid decline in lung function than did control subjects. If this rate of decline persists, these subjects may develop obstructive airways disease in later life.

Neonatal head circumference, neonatal weight, and risk of hayfever, asthma and eczema in a large cohort of adolescents from Sheffield, England

BACKGROUND

Neonatal physical characteristics, including head circumference and birth weight, have been hypothesized to be markers of in utero thymic development. Greater head circumference and lower birth weight have been linked in previous studies to subsequent development of asthma, and greater birth weight has been associated with subsequent development of eczema.

OBJECTIVE

To investigate potential associations between neonatal head circumference and weight and hayfever, asthma and eczema in a cohort of adolescents from Sheffield, England.

METHODS

Responses to a questionnaire inquiring about physician-diagnosed hayfever, asthma and eczema among adolescents in Sheffield, England, were linked to previously recorded measurements of weight at birth and at 1 month and head circumference at 1 month. Logistic regression methods were used to relate diagnoses to neonatal measurements and potential confounders.

RESULTS

The cohort consisted of 10,809 adolescents, of whom 16.5% reported hayfever, 18.0% asthma, and 16.2% eczema. After adjusting for sex, age at the time of the questionnaire, maternal age and gestational age at birth, number of older and younger siblings, time since birth of next older sibling, neonatal sickness, type of neonatal feeding, and maternal and paternal educational backgrounds, hayfever was the only disease associated with neonatal measurements. Comparing the highest with the lowest fifths of distributions, lifetime prevalence of hayfever was positively associated with neonatal head circumference (adjusted odds ratio 1.23, 95% CI 1.03 to 1.47) and with birth weight (1.17, 0.99 to 1.39). Hayfever was inversely related to the ratio of head circumference to birth weight (0.89, 0.75 to 1.05) and to gestational age. The associations with head circumference and birth weight were not substantially altered by further adjustment for gestational age.

CONCLUSION

Greater neonatal head circumference may be associated with an increased risk of hayfever, but the inverse relationship between hayfever prevalence and the ratio of head circumference to birth weight challenges the prior hypothesis that greater head circumference relative to body mass reflects abnormal thymic development in utero, increasing the likelihood of allergic sensitization.

Is the prevalence of specific IgE to classical inhalant aeroallergens among patients with respiratory allergy changing? Evidence from two surveys 15 years apart

OBJECTIVE

The aim of this study was to evaluate the relative frequencies of sensitisation to four common inhalant allergens in two atopic populations suffering from asthma and/or rhinitis. One had been studied in the period of 1975 till 1979, and a second population was evaluated between 1992 and 1995.

DATA SOURCES

At both time periods patients with inhalant allergy and visiting our outpatient clinic were included. Quantification of IgE to Dermatophagoides pteronyssinus, birch, timothy grass, and mugwort was performed via the Phadebas RAST technique (Pharmacia, Brussels, Belgium).

RESULTS

In patients suffering from respiratory allergy the frequency of birch pollen sensitisation significantly increased from 13% in the period 1975-1979 to 34% in the period 1992-1995. In contrast, the frequency of house dust mite, timothy grass pollen, and mugwort pollen sensitisation remained almost unchanged. The increase was not associated with an increase in the birch pollen count.

CONCLUSION

Birch pollen hypersensitivity has almost tripled among atopic subjects during the last 2 decades. The exact mechanisms for this increase remain to be evaluated.

Asthma in adolescence

The care of adolescents with asthma has been largely neglected, yet adolescents have particular needs that differ from those of children or adults with asthma. There are over 800,000 teenagers in the UK who suffer from asthma and underdiagnosis and poor treatment are common. The prevalence and level of morbidity from asthma in adolescents are as high as or higher than the rates in younger schoolchildren. Poor symptom control frequently reflects poor compliance with treatment. The beliefs and fears of teenagers about their asthma and its treatment are often not recognised or addressed in clinical consultations. Improved communication on the part of health professionals, which results in negotiating simple management plans that are tailored to the individual patient's concerns and goals, is more likely to improve compliance and asthma control than are complex plans made unilaterally by the doctor. The transition of care from the paediatric to the adult clinic remains a challenge for paediatricians and there is a lack of consensus over the best method of achieving this.

Effects of changing risk factors on increasing asthma prevalence in southern Taiwan

The study sought to identify factors with consistent relationships with the prevalence of asthma and postulate causes for the increasing prevalence. Reduplication of prevalence surveys was conducted among children of similar ages (6-12 years) from the same area (Tainan City, Taiwan). A total of 7523 primary school children from 1993 and 7224 from 1997 participated in the study. The reported prevalence of diagnosed asthma increased from 6.46% in 1993 to 8.45% in 1997 (relative risk 1.31, 95% CI 1.16, 1.47). Among all environment- and heredity-related factors examined, only four showed consistent relationships with childhood asthma, and all appeared to be a related hereditary condition. Dander allergy is the only factor that increased correspondingly with the prevalence of childhood asthma; therefore, it seems to be the most likely key factor responsible for the increasing trend. The investigation of the interactive effects imposed by the environment- (dander exposure) and heredity-related (atopic sensitisation) factors are recommended for further studies.

Inner-city asthma and the hygiene hypothesis

OBJECTIVE

Our goals were to analyze some of the similarities and differences in the increase in asthma, hay fever, and atopic sensitization between Europe and the United States and attempt to explain "inner-city asthma" within the framework of the hygiene hypothesis.

DATA SOURCES

We reviewed historical descriptions of hay fever and asthma as well as the currently available related literature.

STUDY SELECTION

The authors' judgment was used in the selection of historical and epidemiologic evidence.

RESULTS

Analyses of patterns of risk factors for allergic rhinoconjunctivitis and asthma in Europe led to a causal theory of the epidemic: the hygiene hypothesis. This theory claims that hygiene removed a protective influence against atopy and asthma that was once provided by exposure to infections in early life. This hypothesis has been questioned in the United States, where allergic asthma since the 1970s has increased among minorities living in poverty and with suboptimal hygienic conditions (inner-city asthma). When seen from a historical perspective, the recent increasing trend in respiratory allergies among the less advantaged in the United States may be explained as the consequence of several epiphenomena linked to westernization (including declining exposure to foodborne and orofecal infections) that first affected the richest socioeconomic strata during the 19th century, expanded among the middle classes during the first half of the 20th century, and eventually cascaded down to affect the least-advantaged Americans.

CONCLUSION

Inner-city asthma may be the final stage of a class-driven urbanization and westernization that began 2 centuries ago in the United States and that is now coming full circle.

Elevated serum immunoglobulin E to Cryptomeria japonica pollen in rats exposed to diesel exhaust during fetal and neonatal periods

BACKGROUND: The possible participation of diesel exhaust inhalation during the fetal period in the elevation of IgE against pollen in postnatal life was investigated. METHOD: The experiment was conducted using rat pups. Group I; exposed to clean air (Control). Group 2, 3; exposed to total or filtered diesel exhaust during the fetal period (Total-C-C, Filtered-C-C). Group 4, 5; exposed to total or filtered diesel exhaust during the suckling period (C-Total-C, C-Filtered-C). Group 6,7; exposed to total or filtered diesel exhaust during the weaning period (C-C-Total, C-C-Filtered). Total diesel engine exhaust contained 1.73 mg/m3 particulate matter and 0.79 ppm nitrogen dioxide; filtered exhaust contained the same gases as the total exhaust without particulate matter. Intraperitoneal injection of 5 mg crude cedar pollen was performed at 2-week intervals from the 49th day after birth. RESULTS: The mean IgE titers measured by the P-K reaction in the Control, Total-C-C, Filtered-C-C, C-Total-C, C-Filtered-C, C-C-Total and C-C-Filtered were 64.0 &PlusMinus; 2.7, 469.5 &PlusMinus; 1.6, 332.0 &PlusMinus; 1.7, 380.4 &PlusMinus; 1.7, 394.8 &PlusMinus; 1.7, 115.9 &PlusMinus; 1.3 and 57.0 &PlusMinus; 2.8 respectively after the fourth immunization. There were significant differences between Total-C-C, Filtered-C-C, C-Total-C, C-Filtered-C and Control (p < 0.01, p < 0.01, p < 0.05, p < 0.01, respectively). The mean IgE titers by ELISA were 0.47 &PlusMinus; 0.06, 0.79 &PlusMinus; 0.35, 0.86 &PlusMinus; 0.46, 0.80 &PlusMinus; 0.22, 0.56 &PlusMinus; 0.08, 0.46 &PlusMinus; 0.04 and 0.45 &PlusMinus; 0.03, respectively. IgE titers in Filtered-C-C and C-Total-C were significantly higher than in Control (p < 0.05 for each). CONCLUSIONS: Inhalation of diesel exhaust during differentiation of the immune system accelerated the elevation of IgE against pollen.

Inhaler devices for asthma: do we follow the guidelines?

BACKGROUND

Despite national guidelines for asthma treatment, many children have troublesome symptoms.

AIM

To assess the extent to which the use of inappropriate inhaler devices contributes to this problem.

METHODS

Of 14 813 questionnaires distributed to schoolchildren, 6996 (47%) were returned identifying 1444 children using asthma inhalers. Inhalers were categorised as age appropriate or inappropriate according to national guidelines and were compared with those used by 75 patients attending a hospital clinic.

RESULTS

A total of 35% of "schools" and 4% of "clinic" children reported using an inappropriate inhaler device. Most were using metered dose inhalers alone. Twenty four per cent of "schools" children < or = 5 years old did not use a spacer. Both children and parents overestimated the child's ability to use their inhaler.

CONCLUSIONS

Large numbers of children are given inhalers they cannot use. To improve asthma care we must ensure that prescriptions reflect the age and ability of the child. Recent recommendations by the Department of Health in England and Wales stress the importance of seamless care between primary and secondary services. As the management of childhood asthma is guided primarily by secondary care providers, it is therefore imperative that general paediatricians know the difficulties and issues which are occurring in the community. This will enable them to lead and support necessary change.