Prevalence of respiratory symptoms in Swiss children: is bronchial asthma really more prevalent in boys?

Maternal exposure to pyrethroid insecticides during pregnancy and respiratory allergy symptoms among children participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE)

BACKGROUND

Pyrethroid insecticides use for indoor residual spraying (IRS) in malaria-endemic areas results in high levels of exposure to local populations. Pyrethroids may cause asthma and respiratory allergies but no prior study has investigated this question in an IRS area.

METHODS

We measured maternal urinary concentrations of pyrethroid metabolites (cis-DBCA, cis-DCCA, trans-DCCA, 3-PBA) in samples collected at delivery from 751 mothers participating in the Venda Health Examination of Mothers, Babies, and their Environment (VHEMBE), a birth cohort study based in Limpopo, South Africa. At 3.5-year and 5-year follow-up visits, caregivers of 647 and 620 children, respectively, were queried about children's respiratory allergy symptoms based on validated instruments. We applied marginal structural models for repeated outcomes to estimate associations between biomarker concentrations and asthma diagnosis as well as respiratory allergy symptoms at ages 3.5 and 5 years.

RESULTS

We found that a10-fold increase in maternal urinary cis-DCCA, trans-DCCA and 3-PBA concentrations were associated with more than a doubling in the risk of doctor-diagnosed asthma (cis-DCCA: RR = 2.1, 95% CI = 1.3, 3.3; trans-DCCA: RR = 2.1, 95% CI = 1.1, 3.9; 3-PBA: RR = 2.4, 95% CI = 1.0, 5.8) and an about 80% increase in the risk of wheezing or whistling in the chest (cis-DCCA: RR = 1.8, 95% CI = 1.1, 3.0; trans-DCCA: RR = 1.7, 95% CI = 1.1, 2.6; 3-PBA: RR = 1.8, 95% CI = 1.0, 3.3) and suspected asthma (cis-DCCA: RR = 1.8, 95% CI = 1.1, 3.1; trans-DCCA: RR = 1.8, 95% CI = 1.1, 2.8). We also observed that higher concentrations of cis-DBCA and 3-PBA were related to increases in the risks of dry cough at night (RR = 3.5, 95% CI = 1.3, 9.5) and seasonal rhinoconjunctivitis (RR = 2.0, 95% CI = 1.1, 3.9), respectively.

CONCLUSION

Maternal exposure to pyrethroids may increase the risk of asthma and other respiratory allergy symptoms among preschool children from an IRS area.

Prevalence of childhood cough in epidemiological studies depends on the question used: findings from two population-based studies

BACKGROUND

Epidemiological studies use different questions to assess recurrent cough in children. In two independent population-based studies, we assessed how prevalence estimates of cough vary depending on the questions parents are asked about their child's cough and how answers to the different questions overlap.

METHODS

We analysed cross-sectional data from two population-based studies on respiratory health: LuftiBus in the School (LUIS), conducted in 2013-2016 among 6- to 17-year-school children in the Canton of Zurich, Switzerland, and the 1998 Leicester Respiratory Cohort (LRC) study, UK where we used data from 6- to 8-year-old children from the 2003 follow-up survey. Both studies used parental questionnaires that included the same three questions on the child's cough, namely cough without a cold, dry cough at night and coughing more than others. We assessed how the prevalence of cough varied depending on the question and how answers to the different questions on cough overlapped. We also assessed how results were influenced by age, sex, presence of wheeze and parental education.

RESULTS

We included 3457 children aged 6-17 years from LUIS and 2100 children aged 6-8 years from LRC. All respiratory outcomes - cough, wheeze and physician-diagnosed asthma - were reported twice as often in the LRC as in LUIS. We found large differences in the prevalence of parent-reported cough between the three cough questions. In LUIS, 880 (25%) parents reported cough without a cold, 394 (11%) dry night cough, and 159 (5%) reported that their child coughed more than other children. In the LRC, these numbers were 1003 (48%), 527 (25%) and 227 (11%). There was only partial overlap of answers, with 89 (3%) answering yes to all questions in LUIS and 168 (8%) in LRC. Prevalence of all types of cough and overlap between the cough questions was higher in children with current wheeze.

CONCLUSION

In both population-based studies prevalence estimates of cough depended strongly on the question used to assess cough with only partial overlap of responses to different questions. Epidemiological studies on cough can only be compared if they used exactly the same questions for cough.

Association between Environmental Exposures and Asthma among Children in King Williams Town, South Africa

The study aimed to assess the association between environmental exposure and asthma among children between 3 and 12 years old in King Williams Town, South Africa. A quantitative case-control study was conducted at Grey Hospital to assess the association between environmental exposure and asthma among children who reside in King Williams Town. Of the total 566 study participants, 50.5% (286) had asthma while 49.5% did not. Socio-demographic factors associated with asthma in children were being within the age group 9-12 years (OR 1.74, CI 95% 1.09-2.78) and India ethnicity (OR 0.20, CI 95% 0.08-0.48). Factors associated with asthma were weight within 25-35 kg (OR 1.64, CI 95% 1.11-2.42) and BMI within 15-20 (OR 4.80, CI 95% 2.80-8.22). Environmental risk factors associated with asthma were indoor exposure to tobacco smoke from mothers of the participants (OR 5.45, CI 95% 3.08-9.65) and from fathers (OR 4.37; CI 95% 2.77-6.90). Abstaining from eating seafood appeared to be protective from developing asthma (OR 0.01; CI 95% 0.00-0.05). The study found no significant association between outdoor environmental exposures and childhood asthma. The age of participant, weight, BMI, exposure to environmental tobacco smoke (ETS), and eating seafood had significant correlations with childhood asthma. Strengthening the evaluation of children healthcare and encouraging smoking cessation among parents could reduce exposure to environmental asthma triggers among children.

IL-33 induces NF-κB activation in ILC2 that can be suppressed by in vivo and ex vivo 17β-estradiol

Asthmatic women tend to develop severe airway disease in their reproductive years, and 30%-40% of asthmatic women have peri-menstrual worsening of asthma symptoms. This indicates that fluctuations in ovarian hormones are involved in advancement of asthmatic disease and exacerbation of symptoms. Group 2 innate lymphoid cells, or ILC2, are readily detected in allergic conditions, such as rhinosinusitis, in individuals that develop nasal polyps do to allergen exposures, and in allergic asthma. ILC2 are airway localized immune cells activated by IL-33, an innate cytokine that perpetuates allergic inflammation by driving the production of IL-5 and IL-13. We have previously shown that ILC2 are highly activated in naïve and ovalbumin (OVA) challenged, female BALB/c mice in comparison to male mice following stimulation with IL-33. Here, we investigated the effect of steady-state ovarian hormones on ILC2 and the NF-κB signaling pathway following OVA sensitization and challenge. We found that estrogen-treated ovariectomized mice (OVX-E2) that had been challenged with OVA had reduced IL-5 and IL-13 production by lung ILC2 as compared to lung ILC2 isolated from intact male and female sham-operated controls that had been treated with OVA. ILC2 were isolated from untreated animals and co-cultured ex vivo with and without estrogen plus IL-33. Those estrogen-treated ILC2 similarly produced less IL-5 and IL-13 in comparison to untreated, and had reduced NF-κB activation. Single-cell RNA sequencing showed that 120 genes were differentially expressed in male and female ILC2, and Nfkb1 was found among top-ranked regulatory interactions. Together, these results provide new insight into the suppressive effect of estrogen on ILC2 which may be protective in female asthmatics. Understanding further how estrogen modulates ILC2 may provide therapeutic targets for the treatment of allergic diseases.

Roles of Genetic Predisposition in the Sex Bias of Pulmonary Pathophysiology, as a Function of Estrogens : Sex Matters in the Prevalence of Lung Diseases

In addition to studies focused on estrogen mediation of sex-different regulation of systemic circulations, there is now increasing clinical relevance and research interests in the pulmonary circulation, in terms of sex differences in the morbidity and mortality of lung diseases such as inherent-, allergic- and inflammatory-based events. Thus, female predisposition to pulmonary artery hypertension (PAH) is an inevitable topic. To better understand the nature of sexual differentiation in the pulmonary circulation, and how heritable factors, in vivo- and/or in vitro-altered estrogen circumstances and changes in the live environment work in concert to discern the sex bias, this chapter reviews pulmonary events characterized by sex-different features, concomitant with exploration of how alterations of genetic expression and estrogen metabolisms trigger the female-predominant pathological signaling. We address the following: PAH (Sect.7.2) is characterized as an estrogenic promotion of its incidence (Sect. 7.2.2), as a function of specific germline mutations, and as an estrogen-elicited protection of its prognosis (Sect.7.2.1). More detail is provided to introduce a less recognized gene of Ephx2 that encodes soluble epoxide hydrolase (sEH) to degrade epoxyeicosatrienic acids (EETs). As a susceptible target of estrogen, Ephx2/sEH expression is downregulated by an estrogen-dependent epigenetic mechanism. Increases in pulmonary EETs then evoke a potentiation of PAH generation, but mitigation of its progression, a phenomenon similar to the estrogen-paradox regulation of PAH. Additionally, the female susceptibility to chronic obstructive pulmonary diseases (Sect. 7.3) and asthma (Sect.7.4), but less preference to COVID-19 (Sect. 7.5), and roles of estrogen in their pathogeneses are briefly discussed.

Sex Modifies Acute Ozone-Mediated Airway Physiologic Responses

Sex differences clearly exist in incidence, susceptibility, and severity of airway disease and in pulmonary responses to air pollutants such as ozone (O3). Prior rodent O3 exposure studies demonstrate sex-related differences in the expression of lung inflammatory mediators and signaling. However, whether or not sex modifies O3-induced airway physiologic responses remains less explored. To address this, we exposed 8- to 10-week-old male and female C57BL/6 mice to either 1 or 2 ppm O3 or filtered air (FA) for 3 h. At 12, 24, 48, and 72 h following exposure, we assessed airway hyperresponsiveness to methacholine (MCh), bronchoalveolar lavage fluid cellularity, cytokines and total protein/albumin, serum progesterone, and whole lung immune cells by flow cytometry. Male mice generated consistent airway hyperresponsiveness to MCh at all time points following exposure. Alternatively, females had less consistent airway physiologic responses to MCh, which were more variable between individual experiments and did not correlate with serum progesterone levels. Bronchoalveolar lavage fluid total cells peaked at 12 h and were persistently elevated through 72 h. At 48 h, bronchoalveolar lavage cells were greater in females versus males. Bronchoalveolar lavage fluid cytokines and total protein/albumin increased following O3 exposure without sex differences. Flow cytometry of whole lung tissue identified dynamic O3-induced immune cell changes also independent of sex. Our results indicate sex differences in acute O3-induced airway physiology responses and airspace influx without significant difference in other injury and inflammation measures. This study highlights the importance of considering sex as a biological variable in acute O3-induced airway physiology responses.

Lung function and respiratory outcomes in teenage boys and girls born very prematurely

OBJECTIVES

Male sex in prematurely born infants has been associated with worse respiratory outcomes in early childhood.

WORKING HYPOTHESIS

Respiratory outcomes at 11 to 14 years of age in children born very prematurely and routinely exposed to antenatal corticosteroids and postnatal surfactant would differ according to sex.

STUDY DESIGN

Analysis of follow-up data.

PATIENT-SUBJECT SELECTION

Three hundred and nineteen children born before 29 weeks of gestational age from the United Kingdom Oscillation Study.

METHODOLOGY

Spirometry was used to assess forced expiratory flow at 75%, 50%, and 25% of expired vital capacity (FEF₇₅ , FEF₅₀ , and FEF₂₅ ), forced expiratory volume in 1 second (FEV₁ ), peak expiratory flow (PEF), and forced vital capacity (FVC). Lung volumes were measured using a helium dilution technique (FRC_He ) and by plethysmography (FRC_pleth ). Total lung capacity (TLC) and residual volume (RV) were calculated. Mean lung function measurements were compared using linear mixed models and reported as unadjusted and adjusted for neonatal and age 11 to 14 years factors. The participants also completed health questionnaires and provided a urine sample for assessment of passive or active smoking.

RESULTS

Three (FEF₂₅ , FEF_25-75 , FEV₁ ) lung function measures showed significant differences in favor of females after adjustment. The percentage of children with abnormal lung function (below 5th centile for normal) had adjusted differences between 10 and 30 percentage points, for example, for FEF₂₅ 15% females compared with 26% males.

CONCLUSIONS

Among extremely prematurely born school children airway function was significantly worse in males.

Sex in Respiratory and Skin Allergies

A bulk of literature demonstrated that respiratory allergy, and especially asthma, is prevalent in males during childhood, while it becomes more frequent in females from adolescence, i.e., after menarche, to adulthood. The mechanisms underlying the difference between females and males are the effects on the immune response of female hormones and in particular the modulation of inflammatory response by estrogens, as well as the result of the activity of various cells, such as dendritic cells, innate lymphoid cells, Th1, Th2, T regulatory (Treg) and B regulatory (Bregs) cells, and a number of proteins and cytokines, which include interleukin (IL)-4, IL-5, IL-10, and IL-13. As far as sexual dimorphism is concerned, a gender difference in the expression profiles of histamine receptors and of mast cells was demonstrated in experimental studies. A critical phase of hormone production is the menstrual cycle, which often is associated with asthma deterioration, as assessed by worsening of clinical symptoms and increase of bronchial hyperresponsiveness. In asthmatic woman, there is a high risk to develop more severe asthma during menstruation. The higher prevalence of asthma in females is confirmed also in the post-menopause age, but the underlying mechanisms are not yet understood. In pregnancy, asthma may worsen but may also improve or remain unchanged, with no significant difference in frequency of these three outcomes. For allergic rhinitis, the available studies indicate, likewise asthma, a male predominance in prevalence in childhood that shifts to a female predominance in adolescence and adulthood, but further investigation is needed.

The Roles of Sex Hormones in the Course of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by T helper 2 cell (Th2)-shifted abnormal immunity, skin barrier impairment, and pruritus. The prevalence of AD in childhood is slightly higher in boys than in girls; after puberty, the sexual difference is reversed. The female preponderance in all generations exists in intrinsic AD with enhanced Th1 activity and nickel allergy, lacking increased serum IgE or filaggrin mutation. AD is often deteriorated before menstruation. We review the effects of sex hormones on immune responses and skin permeability barrier and propose possible hypotheses for the above phenomena. After puberty, the immune responses of patients are remarkably influenced by sex hormones. Estrogen and progesterone enhance the activities of Th2/regulatory T cell (Treg) but suppress Th1/Th17. Androgens suppress Th1/Th2/Th17 and induce Treg. The skin permeability barrier is fortified by estrogen but is impaired by progesterone and androgens. Dehydroepiandrosterone suppresses Th2 but enhances Th1. The amount of steroid sulfatase converting dehydroepiandrosterone sulfate to dehydroepiandrosterone is higher in women than in men, and thus, women might be more susceptible to the influence of dehydroepiandrosterone. The balance of modulatory effects of sex hormones on immune responses and skin barrier might regulate the course of AD.

Age-related changes in childhood wheezing characteristics: A whole population study

BACKGROUND

Wheezing illnesses are characterized by phenotypic variability, which changes with age, but few studies report on a wide age range of children. We studied how prevalence, severity, and triggers of wheeze vary throughout childhood.

METHODS

We analyzed data from a large population-based cohort of children from Leicestershire, UK, who were followed from infancy through late adolescence using postal questionnaires. We used generalized estimating equations to describe age-related changes in prevalence of any wheeze: episodic viral and multiple trigger wheeze; wheeze triggered by exercise, aeroallergens, food/drinks, laughing/crying; and of severe wheeze (frequent attacks, shortness of breath, sleep disturbance, disturbance of daily activities) from age 1-18 years. We analyzed this in the entire cohort (absolute prevalence) and separately among children with wheeze (relative prevalence).

RESULTS

This study included 7670 children. Current wheeze was most common in 1-year-olds (36%) and then decreased in prevalence to reach 17% in children aged 14-17 years. Absolute prevalence of episodic viral wheeze (EVW) decreased with age (from 24% to 7%), while multiple trigger wheeze (MTW) remained relatively constant throughout childhood (8-12%). Among children with wheeze, the proportion with EVW decreased, and the proportion with MTW increased with age. In older children, wheeze triggered by exercise or aeroallergens, and wheeze accompanied by shortness of breath became more frequent, while wheeze triggered by food or laughter, and sleep disturbance decreased in prevalence.

CONCLUSION

Knowledge of these age-related changes in wheezing illness is informative for health care planning and the design of future research projects and questionnaires.

Sex-specific lung functional changes in adult mice exposed only to second-hand smoke in utero

Background

An increasing number of epidemiological and experimental studies have associated exposure to second-hand smoke (SHS) during pregnancy with adverse outcomes in newborns. As we have previously shown in mice, in utero exposure to SHS at critical stages of fetal development, results in altered lung responses and increased disease susceptibility upon re-exposure to irritants (SHS or ovalbumin) in adulthood. In this study, we asked whether the in utero SHS exposure alone is sufficient to alter lung structure and function in adult mice.

Methods

Pregnant BALB/c mice were exposed from days 6 to 19 of pregnancy to 10 mg/m³ of SHS or HEPA-filtered air. Male and female offspring (n = 13–15/group) were sacrificed at 15 weeks of age. We measured lung function with non-invasive and invasive methods, performed lung morphometric analysis on trichrome-stained lung tissue samples, and assessed lung gene expression via RNA sequencing and protein assays.

Results

In utero SHS exposure significantly increased mean linear intercept and decreased the surface area per unit volume of the lungs in both males and females, indicating perturbation in alveolar developmental processes. Tidal volume, minute volume and inspiratory capacity were significantly decreased compared with the controls only in male mice exposed in utero to SHS, suggesting that males are more sensitive than females to an SHS insult during lung development. This also suggests that in our model, lung structure changes may be necessary but are not sufficient to impair lung function. SERPINA1A, the mouse ortholog of human α1-antitrypsin, deficiency of which is a known genetic risk factor for emphysema, was down-regulated at the protein level in the in utero SHS-exposed mice. Additionally, DNMT3A protein expression was dysregulated, indicating that DNA methylation occurred in the lungs.

Conclusions

Our results indicate that in utero SHS exposure alone alters both lung function and structure well into adulthood (15 weeks) in male mice. Furthermore, lung function alterations in this model are sex-specific, with males being more susceptible to in utero SHS effects. Overall, our data suggest that in utero SHS exposure alone can predispose to adult lung diseases.

Prevalence of cough throughout childhood: A cohort study

Background

Cough in children is a common reason for medical consultations and affects quality of life. There are little population-based data on the epidemiology of recurrent cough in children and how this varies by age and sex, or between children with and without wheeze. We determined the prevalence of cough throughout childhood, comparing several standardised cough questions. We did this for the entire population and separately for girls and boys, and for children with and without wheeze.

Methods

In a population-based prospective cohort from Leicestershire, UK, we assessed prevalence of cough with repeated questionnaires from early childhood to adolescence. We asked whether the child usually coughed more than other children, with or without colds, had night-time cough or cough triggered by various factors (triggers, related to increased breathing effort, allergic or food triggers). We calculated prevalence from age 1 to 18 years using generalised estimating equations for all children, and for children with and without wheeze.

Results

Of 7670 children, 10% (95% CI 10–11%) coughed more than other children, 69% (69–70%) coughed usually with a cold, 34% to 55% age-dependently coughed without colds, and 25% (25–26%) had night-time cough. Prevalence of coughing more than peers, with colds, at night, and triggered by laughter varied little throughout childhood, while cough without colds and cough triggered by exercise, house dust or pollen became more frequent with age. Cough was more common in boys than in girls in the first decade of life, differences got smaller in early teens and reversed after the age of 14 years. All symptoms were more frequent in children with wheeze.

Conclusions

Prevalence of cough in children varies with age, sex and with the questions used to assess it, suggesting that comparisons between studies are only valid for similar questions and age groups.

Biomass fuel exposure and asthma symptoms among rural school children in Nigeria

BACKGROUND

Approximately 70% of rural Nigerian households rely on biomass fuels for cooking. The International Study of Asthma and Allergies in Childhood (ISAAC) estimates the prevalence of current wheeze among children in Nigeria to have risen from 10.7% in 1999 to approximately 20% in 2014.

OBJECTIVE

To examine the effects of biomass smoke exposure on asthma symptom prevalence in rural children in Nigeria.

METHODS

We conducted a cross-sectional survey in rural communities in Nigeria. Asthma symptoms were defined according to ISAAC definitions. Biomass smoke exposure was determined by the types of fuel used for cooking. Logistic regression was used to explore associations between biomass smoke and asthma symptoms.

RESULTS

The study population comprised 1,690 school children, of which 865 lived in households cooking with biomass and 825 lived in households not using biomass. Asthma symptoms were reported in 481 (28.5%) children. Biomass fuel was associated with increased odds of asthma symptoms. Adjusted odds ratios (aORs) were 1.38 (95% CI: 1.05-1.80) for nocturnal cough, 1.26 (95% CI: 1.00-1.61) for current wheeze, and 1.33 (95% CI: 1.05-1.69) for report of any asthma-related symptoms. Sex modified the associations between asthma symptoms with biomass fuel: aORs were stronger and significant for males (nocturnal cough = 1.85, 95% CI: 1.24-2.76; current wheeze = 1.48, 95% CI: 1.03-2.13; report of any asthma-related symptoms = 1.60, 95% CI: 1.12-2.28), but weaker and non-significant for females.

CONCLUSION

The risk of asthma symptoms related to biomass smoke exposure appears to differ by sex.

Sex Differences in the Relationship between Fitness and Obesity on Risk for Asthma in Adolescents

OBJECTIVE

To evaluate the relationship of fitness and obesity on asthma risk in adolescent girls and boys.

STUDY DESIGN

A cross-sectional assessment of participants 12-19 years of age was conducted by the use of data from the 1999-2004 National Health and Nutrition Examination Survey. Participants completed cardiorespiratory fitness testing, body composition measurements, and respiratory questionnaires.

RESULTS

A total of 4828 participants were included. Overweight/obesity was associated with increased odds of history of asthma (aOR 1.63, 95% CI 1.16-2.30), current asthma (aOR 1.73, 95% CI 1.13, 2.64), and wheezing (aOR 1.40, 95% CI 1.03-1.91) in girls. Overweight/obesity also was associated with increased odds of asthma attacks (aOR 2.67, 95% CI 1.56-4.65) and wheezing related to exercise (aOR 1.60, 95% CI 1.07-2.38) in girls. High fitness was associated with lower odds of asthma-related visits to the emergency department (aOR 0.24, 95% CI 0.07-0.89), wheezing-related medical visits (aOR 0.31, 95% CI 0.13-0.75), wheezing-related missed days (aOR 0.14, 95% CI 0.06-0.33), and wheezing related to exercise (aOR 0.43, 95% CI 0.24-0.76) in boys.

CONCLUSION

Overweight/obesity is associated with increased asthma prevalence and morbidity in girls but not in boys, independent of fitness. High fitness is associated with decreased rates of asthma morbidity in boys but not in girls, independent of weight status. Obesity and fitness may each influence asthma onset and severity in different ways for girls compared with boys.

Impact of Age and Sex on Outcomes and Hospital Cost of Acute Asthma in the United States, 2011-2012

Background

Worldwide, asthma is a leading cause of morbidity, mortality and economic burden, with significant gender and racial disparities. However, little attention has been given to the independent role of age on lifetime asthma severity and hospitalization. We aimed to assess the effect of age, gender, race and ethnicity on indicators of asthma severity including asthma related hospitalization, mortality, hospital cost, and the rate of respiratory failure.

Methods

We analyzed the 2011 and 2012 Healthcare Cost and Utilization Project- National Inpatient Sample (NIS). We validated and extended those results using the National Heart, Lung, and Blood Institute-Severe Asthma Research Program (SARP; 2002–2011) database. Severe asthma was prospectively defined using the stringent American Thoracic Society (ATS) definition.

Results

Hospitalization for asthma was reported in 372,685 encounters in 2012 and 368,528 in 2011. The yearly aggregate cost exceeded $2 billion. There were distinct bimodal distributions for hospitalization age, with an initial peak at 5 years and a second at 50 years. Likewise, this bimodal age distribution of patients with severe asthma was identified using SARP. Males comprised the majority of individuals in the first peak, but women in the second. Aggregate hospital cost mirrored the bimodal peak distribution. The probability of respiratory failure increased with age until the age of 60, after which it continued to increase in men, but not in women.

Conclusions

Severe asthma is primarily a disease of young boys and middle age women. Greater understanding of the biology of lung aging and influence of sex hormones will allow us to plan for targeted interventions during these times in order to reduce the personal and societal burdens of asthma.

CHI3L1 polymorphisms, cord blood YKL-40 levels and later asthma development

BACKGROUND

Single nucleotide polymorphisms (SNPs) in chitinase 3-like 1 (CHI3L1), the gene encoding YKL-40, and increased serum YKL-40 levels are associated with severe forms of asthma. It has never been addressed whether SNPs in CHI3L1 and cord blood YKL-40 levels could already serve as potential biomarkers for milder forms of asthma. We assessed in an unselected population whether SNPs in CHI3L1 and cord blood YKL-40 levels at birth are associated with respiratory symptoms, lung function changes, asthma, and atopy.

METHODS

In a prospective birth cohort of healthy term-born neonates (n = 260), we studied CHI3L1 polymorphisms, and measured cord blood YKL-40 levels by ELISA in (n = 170) infants. Lung function was performed at 5 weeks and 6 years. Respiratory health during the first year of life was assessed weekly by telephone interviews. Diagnosis of asthma and allergic sensitisation was assessed at 6 years (n = 142).

RESULTS

The SNP rs10399805 was significantly associated with asthma at 6 years. The odds ratio for asthma was 4.5 (95 % CI 1.59-12.94) per T-allele. This finding was unchanged when adjusting for cord blood YKL-40 levels. There was no significant association for cord blood YKL-40 levels and asthma. SNPs in CHI3L1 and cord blood YKL-40 were not associated with lung function measurements at 5 weeks and 6 years, respiratory symptoms in the first year, and allergic sensitisation at 6 years.

CONCLUSION

Genetic variation in CHI3L1 might be related to the development of milder forms of asthma. Larger studies are warranted to establish the role of YKL-40 in that pathway.

Asthma Is More Severe in Older Adults

Background

Severe asthma occurs more often in older adult patients. We hypothesized that the greater risk for severe asthma in older individuals is due to aging, and is independent of asthma duration.

Methods

This is a cross-sectional study of prospectively collected data from adult participants (N=1130; 454 with severe asthma) enrolled from 2002 – 2011 in the Severe Asthma Research Program.

Results

The association between age and the probability of severe asthma, which was performed by applying a Locally Weighted Scatterplot Smoother, revealed an inflection point at age 45 for risk of severe asthma. The probability of severe asthma increased with each year of life until 45 years and thereafter increased at a much slower rate. Asthma duration also increased the probability of severe asthma but had less effect than aging. After adjustment for most comorbidities of aging and for asthma duration using logistic regression, asthmatics older than 45 maintained the greater probability of severe asthma [OR: 2.73 (95 CI: 1.96; 3.81)]. After 45, the age-related risk of severe asthma continued to increase in men, but not in women.

Conclusions

Overall, the impact of age and asthma duration on risk for asthma severity in men and women is greatest over times of 18-45 years of age; age has a greater effect than asthma duration on risk of severe asthma.

Associations of age, gender, and BMI with prevalence of allergic diseases in children: PATCH study

BACKGROUND

Little is known about the prevalence of allergic diseases in children of different ages. This study aimed to investigate the prevalence of allergic diseases and allergic sensitization in children over a wide age range, with emphasis on the influence of age, gender, and body mass index (BMI).

METHODS

In a cross-sectional study, we assessed 5351 Taiwanese children aged 4-18 years using an International Study of Asthma and Allergies in Childhood questionnaire, BMI, and total and specific serum immunoglobulin E.

RESULTS

Forty-eight percent were currently symptomatic for at least one of three allergic diseases. Prevalence of wheeze ever, current wheeze, and diagnosed asthma were 17.0%, 7.5%, and 9.8%, respectively; analogous features for rhinitis were 47.8%, 44.2%, and 39.8%. Allergic sensitization was very common (57.3%). Half of the children (50.6%) with current wheeze had not been diagnosed with asthma by physicians, whereas undiagnosed rates were 32.3% for rhinitis and 25.3% for eczema. The male-to-female prevalence ratios of current wheeze increased with age from <1 at 4-5 years, peaked at 10-11 years (2.24), then reversed to 0.57 at 16-18 years. Childhood wheezing tended to remit with age, but rhinitis and eczema were more persistent. Total immunoglobulin E levels increased with age until 14-15 years, and declined thereafter. Elevated BMI was associated with greater prevalence of wheezing and eczema, with no evidence of significant effect modification by either gender or age. Multivariate analyses revealed that younger age, boys, and obesity were significantly and independently associated with current wheezing in children (all p < .01).

CONCLUSIONS

The burden and co-morbidity of childhood allergies are substantial. There are striking age-dependent gender differences in asthma prevalence, exhibiting an inverted U-shaped curve for male-to-female prevalence ratios by age. Obesity is associated with a greater prevalence of asthma in children with no evidence of a significant modulation by either gender or age.

Prevalence of self-perceived allergic diseases and risk factors in Italian adolescents

The aim of the study was to assess the symptoms prevalence of allergic diseases in a population of 11-15 yr old schoolchildren, to evaluate the associations between asthma and other symptoms and identify risk factors for asthma, rhinitis and eczema syndromes. A sample of 481 students was studied using an International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Prevalence of different kind of self-reported symptoms was calculated. Using a logistic regression approach, we tried to identify risk factors for three syndromes - rhinitis, eczema and asthma. The highest and the lowest prevalence rates of self-reported symptoms were recorded for rhinitis (43.6%) and for eczema (8.1%), respectively. The prevalence of asthma was 15.7%. Univariate analysis showed a mutual association between wheeze and rhinitis symptoms. Multivariate logistic regression model for eczema syndrome revealed female gender as a significant risk factor. The polytomic logistic multivariate regression revealed female gender and family history of allergy as significant risk factors for rhinitis syndrome only, and maternal smoking and familial allergy for rhinitis and asthma together. In particular, familial allergy yields a 400% higher chance of developing asthma and rhinitis together. The synergistic effect of familial allergy on rhinitis and asthma syndromes suggests the implementation of preventive measures in children with family history of these diseases.

Preschool asthma in Italy: prevalence, risk factors and health resource utilization

Asthma in preschool children is greatly under-diagnosed worldwide. Aim was to investigate prevalence of wheezing, and asthma risk factors, doctor diagnosis, treatment and health resource utilization in preschool children. About 1402 children (3-5 years) attending local kindergartens participated in the study. The International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire (WQ) was used with additional questions on risk factors, asthma diagnosis, treatments, resource utilization. Allergic sensitisation was evaluated by skin prick tests for the common allergens. Prevalence of "wheezing in previous 12 months" and "doctor diagnosed asthma" were 12.1% and 8.6%, respectively. 4.7% of children have had both wheezing in the last 12 months and asthma diagnosis. Significant risk factors for wheezing were rhinitis, parental history of atopy and sensitivity to mites and grass pollens. 27.3% of children with asthma diagnosis, but only 4.9% of children without diagnosis, received regular treatment during the previous year (p<0.0001). Children with more than 4 episodes of wheezing a year received more frequently an asthma diagnosis, but 68.6% were not on regular treatment. Asthma diagnosis was associated with a significant increase in control visits for wheezing (p<0.0001). The prevalence of children requiring at least one hospital emergency visit in the previous year was not different among the two groups (83.3% vs. 82.5%). In preschool children the prevalence of wheezing and asthma is elevated. Preschool asthma seems to be under-treated with few cases receiving regular therapy. The social cost of the disease at this age seems to be elevated because of the high frequency of control and emergency visits.

Impact of gender on asthma in childhood and adolescence: a GA2LEN review

A number of studies have shown gender differences in the prevalence of wheeze and asthma. The aim of this review was to examine published results on gender differences in childhood and adolescent asthma incidence and prevalence, define current concepts and to identify new research needs. A Medline search was performed with the search words (gender OR sex) AND (child OR childhood OR adolescence) AND (asthma). Articles that reported on absence or presence of gender differences in asthma were included and reviewed, and cross-references were checked. Boys are consistently reported to have more prevalent wheeze and asthma than girls. In adolescence, the pattern changes and onset of wheeze is more prevalent in females than males. Asthma, after childhood, is more severe in females than in males, and is underdiagnosed and undertreated in female adolescents. Possible explanations for this switch around puberty in the gender susceptibility to develop asthma include hormonal changes and gender-specific differences in environmental exposures. This aspect needs consideration of the doctors and allergists who diagnose and treat asthmatic individuals. In conclusion, sex hormones are likely to play an important role in the development and outcome of the allergic immune response and asthma in particular. By obtaining functional data from appropriate models, the exact underlying mechanisms can be unravelled. To examine the effect of gender-specific differences in environmental exposures and changes of asthma prevalence and severity in puberty, larger populations may need to be investigated.

Is childhood asthma still underdiagnosed and undertreated in Istanbul?

BACKGROUND

Childhood asthma is reported to be underdiagnosed and undertreated worldwide. The purpose of the present study was to investigate the rate of underdiagnosis and undertreatment among children diagnosed with asthma in a tertiary reference center in Turkey.

METHODS

A questionnaire survey was carried out among the parents of 1134 patients diagnosed with asthma in a tertiary reference outpatient clinic.

RESULTS

Mean age of the patients was 4.9 years (range 1-17 years). Of these children 45.5% had recurrent asthma attacks (average 4.8 attacks per year) and 24.7% had only the symptom of vigorous fits of coughing. Although they had been symptomatic for 29.6 months, only 41.1% were diagnosed as having asthma before admission to the clinic. In this study group 61.3% had received some form of asthma treatment, but only 21.1% of all patients were treated according to the guidelines. The rate of treatment according to guidelines was lower in the children under 6 years of age than older children (18.8 vs 24.2%, respectively, P = 0.02).

CONCLUSIONS

Underdiagnosis and undertreatment of childhood asthma still seem to be a major problem in the management of childhood asthma, especially in preschool children, even after the recommendations of guidelines.

Time trend of asthma prevalence among school children in Taiwan. [corrected]

The standardized International Study of Asthma and Allergies in Childhood (ISAAC) is a valid tool in assessing prevalence of asthma indices. In order to determine the time trends of childhood asthma in Taiwan, we compared data from nationwide ISAAC surveys from a very large sample of Taiwanese 12- to 15-year-old school children, using ISAAC core written and video questionnaires. The number of participants was 44,104 in 1995-96 (phase I) and 11,048 in 2001 (phase III). We found a general tendency towards an increase in lifetime prevalence of physician-diagnosed asthma and asthma symptoms between two surveys, more marked for girls than for boys. Most of the 12-month prevalence of asthma symptoms decreased among boys but stabilized among girls. When comparing different severity levels, we also noted that the decreasing trends of current symptoms were more marked with regard to severe symptoms than mild symptoms in both sexes. A combination of both improved awareness and management of asthma might in part explain this circumstance. Over the past decade in Taiwan, the lifetime prevalence of childhood asthma was increasing, more marked among girls; however, the 12-month prevalence of asthma symptoms was decreasing, mostly among boys. The exact reasons for such trends remain to be explored.

Asthma and wheezing symptoms in young people in six Western countries

BACKGROUND

Asthma diagnosed in children shows wide geographical variations. Large scale surveys identify children with diagnosed asthma, but neglect the group of youngsters with multiple asthmatic complaints.

METHODS

A short validated asthma questionnaire was included in six national surveys of the Health Behaviour in School-Aged Children Study. Prevalence rates are presented by country, gender and age. Gender and age differences are analysed using binary and multinomial logistic regressions controlling for age and smoking.

RESULTS

Large country differences are observed in the prevalence rates of diagnosed asthma (8.6%-20.9% in boys, 6.9%-18.5% in girls) and young people with "asthma-like symptoms" (9.6%-20.2% in boys, 9.2%-23.1% in girls). When controlling for age and smoking, significant gender differences are observed (more diagnosed asthma in boys, more asthmatic symptoms in girls). Age differences were observed in adolescents with "asthma-like symptoms", but not in diagnosed asthma.

CONCLUSIONS

Using a short asthma questionnaire, large differences in diagnosed asthma and wheezing symptoms are observed between the countries. A considerable group of youngsters with "asthma-like symptoms" is detected in all countries, and may be an unrecognised risk group in health promotion.

Sex influences on lung function and medication in childhood asthma

AIM

To evaluate possible sex differences in prevalence, diagnosis and treatment of asthma, and influence on lung function associated with asthma severity in a population-based birth cohort (BAMSE) of 4089 children.

METHODS

At 4-y follow-up, 92% responded to a questionnaire on symptoms of asthma, current medication and doctor's diagnosis of asthma. A total of 2965 children participated in clinical testing, including measurements of peak expiratory flow (PEF), and were assigned to groups of asthma or no asthma by reported airway symptoms.

RESULTS

Children in asthma groups had lower PEF readings compared to healthy children. This effect was most pronounced for both sexes in the persistent group (boys p<0.05, girls p<0.001) and for girls in the transient group (p<0.01). A doctor's diagnosis of asthma did not significantly differ between boys and girls, but significantly more boys than girls had inhaled corticosteroids, even when stratifying by frequency of symptoms.

CONCLUSION

These results suggest that when 4-y-old children are stratified according to common diagnostic criteria, girls have a larger effect on PEF of asthma symptoms and are less frequently treated compared to boys.

The therapy of pre-school wheeze: appropriate and fair?

The current study aimed to assess prevalence and distribution of use of asthma medication for wheeze in pre-school children in the community. We sent a postal questionnaire to the parents of a random population-based sample of 4,277 UK children aged 1-5 years; 3,410 participated (children of south Asian decent were deliberately over-represented). During the previous 12 months, 18% of the children were reported to have received bronchodilators, 8% inhaled corticosteroids (ICS) and 3% oral corticosteroids. Among current wheezers these proportions were 55%, 25%, and 12%, respectively. Use of ICS increased with reported severity of wheeze, but did not reach 60% even in the most severe category. In contrast, 42% of children receiving ICS reported no or very infrequent recent wheeze. Among children with the episodic viral wheeze phenotype, 17% received ICS compared with 40% among multiple-trigger wheezers. Use of ICS by current wheezers was less common in children of South Asian ethnicity and in girls. Although a high proportion of pre-school children in the community used asthma inhalers, treatment seemed to be insufficiently adjusted to severity or phenotype of wheeze, with relative under-treatment of severe wheeze with ICS, especially in girls and South Asian children, but apparent over-treatment of mild and episodic viral wheeze and chronic cough.

Prevalence and severity of asthma, rhinitis, and atopic eczema in 13- to 14-year-old schoolchildren from southern Brazil

The objective of this study was to investigate the prevalence and severity of asthma, rhinitis, and atopic eczema in schoolchildren from southern Brazil. A cross-sectional study was carried out with the International Study of Asthma and Allergies in Childhood phase III written questionnaire. The questionnaire was self-applied by 2,948 randomly selected schoolchildren aged 13 to 14 years. The lifetime prevalence rates of symptoms were as follows: wheezing, 40.8%; rhinitis, 40.7%; eczema, 13.6%; self-reported asthma, 14.6%; rhinitis, 31.4%; eczema, 13.4%. Rhinitis was reported by 55% of adolescents with current asthma (60% females vs 46.9% males). Girls 13 to 14 years of age had higher prevalence rates of asthma, rhinitis, and eczema than boys had. Atopic eczema was reported by 42.7% of girls and 31.4% of boys with asthma. The prevalence rates were statistically significant for symptoms of asthma, rhinitis, and atopic eczema in females. However, there were no statistically significant differences between the sexes in regard to reported asthma and bronchospasm induced by exercise.

Atopic diseases and related risk factors among Dutch adolescents

BACKGROUND

The aim of the present study was to gain insight into the prevalence of asthma, allergic rhinitis, and eczema among Dutch early adolescents, and to study the impact of several social demographic and individual risk factors.

METHODS

Cross-sectional survey study using the self-report questionnaires of the International Study of Asthma and Allergies in Childhood (ISAAC). In January 2003, 10 087 12- to 14-year-old students from 33 secondary schools in four regions of the Netherlands participated in this study.

RESULTS

Of all participants, 52.6% reported that they had an allergic disease at least once in their lifetime. The 12 months prevalence of wheezing, rhinitis, and itchy rash was 12.3%, 28.3%, and 13.5%, respectively. Several social demographic and individual factors (gender, age, education levels, ethnicity, body mass index, and residential area) were significantly associated with the atopic symptoms and diseases.

CONCLUSION

This study showed that allergic conditions are common in the Netherlands. Several social demographic and individual risk factors were related to the atopic diseases and symptoms.

Prevalence of asthma, rhinitis, and eczema from ISAAC survey of schoolchildren in Central Taiwan

Asthma is a common disease among schoolchildren in Taiwan. It is clearly a trend that the prevalence of asthma, rhinitis, and eczema has been increasing in developed countries such as Taiwan, but the data remain limited. This study is part of an effort to evaluate the epidemiology of asthma, rhinitis and eczema in Taiwan and to assess the prevalence and severity of those disorders among school age in central Taiwan. The International Study of Asthma and Allergies in Childhood (ISAAC, phase III) standard written questionnaire was administered to 7,873 first grade schoolchildren, 6 to 8 years of age from 47 different elementary schools in Changhwa county, which is located in central Taiwan. The overall cumulative and 12-month prevalence of wheezing is 10.4% and 5.0%, respectively. The prevalence of diagnosed asthma by doctor is 7.0%. Rhinitis is 24.6% and eczema 18.0%. Multiple logic regression analysis shows that a higher prevalence of wheezing and rhinitis is associated with males. Among these school-age children, the peak incidence of asthma and rhinitis is in the winter months, especially in December and January.We also compared the prevalence of asthma, rhinitis, and eczema in two severely polluted areas in Changhwa County with the prevalence in less polluted parts of the county. One is the area near a huge petrochemical company, TaiHao Petroleum Company, located in the central area of the county. The other is XiZhao, a rural area located near an incinerator. These were compared with the less-polluted Coast-Area and with the rest Changhwa County area. The school-age children living near the TaiHao Company have a higher prevalence of wheezing, diagnosed asthma, and diagnosed eczema, but there are no differences for rhinitis. As for XiZhao and Coast areas, those children have significantly higher rates of nasal problems, diagnosed rhinitis, and eczema than the rest of the area, but we did not find a significant difference in the prevalence of asthma. Among school-age children who lived in the Coast area, we found a higher prevalence of rhinitis and nasal problems with associated itchy eyes than among children in other areas of the county.

Phenotype definition, age, and gender in the genetics of asthma and atopy

When studying genetics of complex diseases it is important to have a clearly described and objective phenotype. When drawing conclusions in association studies, age and gender of the population should be considered. Until we know what causes phenotypic differences between males and females and between children and adults, we should try to study longitudinal cohorts with phenotype assessment at different time points and stratify our analyses for gender. To acquire sufficient power for these types of analyses, international collaboration may be the only way to elucidate the intricate, gene-environmental interactions in atopy and asthma in an age- and gender-dependent manor.

Gender differences in respiratory symptoms in 19-year-old adults born preterm

Objective

To study the prevalence of respiratory and atopic symptoms in (young) adults born prematurely, differences between those who did and did not develop Bronchopulmonary Disease (BPD) at neonatal age and differences in respiratory health between males and females.

Methods

Design: Prospective cohort study.

Setting: Nation wide follow-up study, the Netherlands.

Participants: 690 adults (19 year old) born with a gestational age below 32 completed weeks and/or with a birth weight less than 1500 g. Controls were Dutch participants of the European Community Respiratory Health Survey (ECRHS).

Main outcome measures: Presence of wheeze, shortness of breath, asthma, hay fever and eczema using the ECRHS-questionnaire

Results

The prevalence of doctor-diagnosed asthma was significantly higher in the ex-preterms than in the general population, whereas eczema and hay fever were significant lower. Women reported more symptoms than men. Preterm women vs controls: asthma 13% vs 5% (p < 0.001); hay fever 8% vs 20% (p < 0.001); eczema 10% vs 42% (p < 0.001). Preterm men vs controls: asthma 9% vs 4% (p = 0.007); hay fever 8% vs 17% (p = 0.005); eczema 9% vs 31% (p < 0.001) Preterm women reported more wheeze and shortness of breath during exercise (sob) than controls: wheeze 30% vs 22% (p = 0.009); sob 27% vs 16% (p < 0.001); 19-year-old women with BPD reported a higher prevalence of doctor diagnosed asthma compared to controls (24% vs 5% p < 0.001) and shortness of breath during exercise (43% vs 16% p = 0.008). The prevalence of reported symptoms by men with BPD were comparable with the controls.

Conclusion

Our large follow-up study shows a higher prevalence of asthma, wheeze and shortness of breath in the prematurely born young adults. 19-year-old women reported more respiratory symptoms than men. Compared to the general population atopic diseases as hay fever and eczema were reported less often.

Adolescent respiratory symptoms--girls are at risk: the Young-HUNT study, Norway

The objective was to study sex differences in adolescence regarding prevalence of asthma and current wheeze and to explore the association between respiratory symptoms and hereditary, lifestyle and socioeconomic factors. Young-HUNT included data comprehensive questionnaire on health, disease, lifestyle and social factors from 8817 teenagers 13-19 years conducted in 1995/97 (89% response rate). Questionnaire on respiratory symptoms was based on the International Study of Asthma and Allergy in Childhood (ISAAC). In age groups 13-16 and 17-19 years, current wheeze was reported by 29.0% and 33.5% among girls and 20.4% and 22.1% among boys, whilst the corresponding figures for asthma were 8.5% and 12.2% among girls and 7.1% and 7.0% among boys. Both wheeze and asthma were significantly more prevalent and increased with age in girls compared to boys. Heredity was associated with asthma, but the association was strongest between parents and children of the same sex. Environmental smoking was associated with asthma and wheeze in girls only. Girls reported more asthma and wheeze in association with overweight compared to boys. Girls reported more wheeze and asthma than boys and seemed more susceptible to risk factors such as environmental smoking and overweight than boys. Moreover, girls with mothers having asthma were more likely to be diagnosed as asthmatics themselves.

Change in prevalence of asthma in Danish children and adolescents

BACKGROUND

There is evidence suggesting that the prevalence of asthma has increased, especially in industrialized countries.

OBJECTIVE

To investigate whether the prevalence of asthma in Danish children and adolescents has changed during the past 15 years.

METHODS

Serial cross-sectional studies of 2 different random population samples of children aged 7 to 17 years, living in urban Copenhagen, Denmark, were performed 15 years apart. The first cohort was investigated in 1986 (n = 527) and the second in 2001 (n = 480). The same methods were applied at both occasions. Skin test reactivity was measured using standard techniques. Asthma was defined on the basis of questionnaire responses and was regarded as nonatopic (intrinsic) if no positive reactions were observed on the skin test and as atopic (extrinsic) if at least 1 positive reaction was noted. Current asthma was defined as symptoms within the preceding 12 months.

RESULTS

The prevalence of current asthma increased from 5.3% in 1986 to 11.7% in 2001. This was primarily due to an increase in intrinsic asthma, which was 4.2-fold (1.5% to 6.4%), compared with extrinsic asthma, which increased only 1.4-fold (3.8% to 5.5%). The changes were more pronounced in girls.

CONCLUSIONS

The prevalence of asthma has increased substantially during the past 15 years. The observed striking increase in intrinsic asthma suggests the possibility of a more heterogeneous disorder, involving more important factors than atopy. Furthermore, our findings suggest that asthma might be shifting toward female predominance in childhood.

Childhood asthma management and control. Analysis of the Student Lung Health Survey (SLHS) database, Canada 1996

The objective of this study was to estimate the severity of childhood asthma in Canada, identify the effects of asthma interventions in different target groups, and to profile asthma management and control practices by geographic area, sex, age, and severity groups.

METHODS

The SLHS was conducted as a stratified and multi-staged cluster survey across Canada in 1996. It included a total of 136 public, private and separate schools in nine health units (Prince Edward Island, Halifax, Sherbrooke, Kingston, Guelph, Winnipeg, Saskatoon, Edmonton, and Kelowna). The target study population was schoolchildren aged 5 to 19 years. Descriptive analyses were used to calculate the severity of childhood asthma for the different groups. Logistic regression was then employed to measure the quality of asthma intervention and control. Multivariate logistic regression was also used to compare the severity and treatment of asthma with age, sex and lifestyle, living and housing conditions. Using existing Clinical Practice Guidelines as a reference, the study also evaluated the effectiveness of interventions such as treatment, and asthmatic education.

RESULTS

Based on the Canadian Consensus Recommendations of definition of asthma control, among all 5-19 years old students, 39.9% were well controlled, 33.8% were acceptably controlled and 26.3% were poor controlled. The rates of intermittent and mild asthma were 44.8% and 11.6% compared with moderate (15.3%) and severe (0.9%). Students with asthma reported receiving more advantaged information from a demonstration of inhaler users (OR = 7.51, 95% CI = 5.65-8.94), during a medical visits (OR = 6.33, 95% CI = 5.11-7.83), from the pamphlet/brochures (OR = 6.22, 95% CI = 5.05-7.76) or from a demonstration of the correct use of medicine (OR = 5.62, 95% CI = 4.62-6.82). More students visited a family doctor (40.3%, OR = 5.52, 95% CI = 4.95-6.64) and medical specialists (31.0%, OR = 3.69, 95% CI = 2.58-4.78) than other specialist when they had respiratory problems.

CONCLUSIONS

The results of the SLHS study demonstrated variations in the management and control of childhood asthma across Canada. The interventions and the practice guidelines for asthma control are useful for preventing and controlling asthma. These findings provide indications of interventions that are being used for the control of asthma in Canada.

Indoor and outdoor environmental exposures, parental atopy, and physician-diagnosed asthma in Taiwanese schoolchildren

OBJECTIVE

Parental atopy and environmental exposures are recognized risk factors for childhood asthma. However, the relative contributions of specific risk factors and the overall contributions of indoor and outdoor exposures remain unexplored. This study was undertaken to identify risk factors, estimate the population attributable risk of each exposure, and compare the data for boys versus girls for physician-diagnosed asthma in Taiwanese schoolchildren.

METHODS

During a February to June 2001 cross-sectional national survey, 35 036 6- to 15-year-old schoolchildren were chosen from 22 elementary and 22 middle schools located within 1-km catchment areas of 22 air-monitoring stations in Taiwan. The main outcome measure was physician-diagnosed asthma, as reported by the parents. We investigated hereditary and indoor and outdoor environmental factors for childhood asthma by questionnaire. The adjusted prevalences of questionnaire-determined outdoor indicators were also compared with air-monitoring data.

RESULTS

Outdoor air pollutants were associated with parent-reported perceived ambient air pollution. Physician-diagnosed asthma was reported for 8.1% of the boys (1330 of 16 441) and 5.6% of the girls (894 of 16 056). The risk of physician-diagnosed asthma was significantly associated with parental atopy and perceived ambient air pollution in both sexes. The presence of visible cockroaches (odds ratio [OR]: 1.30; 95% confidence interval [CI]: 1.07-1.59), mold on walls at home (OR: 1.20; 95% CI: 1.01-1.41), and water damage (OR: 1.33; 95% CI: 1.02-1.70) were also associated with asthma in girls; however, only visible mold on walls at home was related to asthma in boys. Mutually adjusted analytical models produced statistically significant associations between any indoor factor and asthma in girls (OR: 1.24; 95% CI: 1.00-1.56) but not in boys (OR: 1.04; 95% CI: 0.87-1.25). For all hereditary and environmental factors, the total population attributable risk was 44.31% in boys and 60.61% in girls.

CONCLUSIONS

Parental atopy contributed more to childhood asthma than indoor or outdoor environmental factors. Girls may be more susceptible to indoor factors than boys.

Are asthma and allergies in children and adolescents increasing? Results from ISAAC phase I and phase III surveys in Münster, Germany

OBJECTIVE

To assess time trends in symptoms of asthma, allergic rhinitis, and atopic eczema among children in Münster, Germany.

METHODS

Two cross-sectional surveys 5-years apart (1994/1995, 1999/2000) using ISAAC core written and video questionnaires and applying the ISAAC protocol. Two main age groups (6-7 and 13-14 year olds) were designated with information collected by parental and self-report for both age groups, respectively. A school-based sample of 7744 participants in the 1994/1995 survey and 7962 participants in the 1999/2000 survey was recruited. In the first and second surveys, response rates for the 6-7 year olds were 81 and 82%, respectively, while for the 13-14 year olds response rates were 94% in both. Analyses focus on the change in 12-month prevalence of symptoms of asthma, rhinitis, and eczema.

RESULTS

There is a tendency towards an increase in current symptoms for all three conditions and in both age groups, but more so among girls. Indices of diagnosis either remained the same or increased in parallel to the increase in symptoms. Indices of severity also showed a homogenous increase in the 5-year study period.

CONCLUSIONS

Our study shows that symptoms of asthma, rhinitis, and eczema are increasing, reflecting a change in the morbidity of these conditions in our population.

Who gets diagnosed with asthma? Frequent wheeze among adolescents with and without a diagnosis of asthma

OBJECTIVE

1). To describe the factors associated with not receiving an asthma diagnosis among children with frequent wheezing symptoms and 2). to determine risk factors for frequent wheezing in the population.

METHODS

The North Carolina School Asthma Survey provided self-reported questionnaire data on respiratory health from 122 829 children ages 12 to 18 years enrolled in 499 public middle schools in North Carolina during the 1999-2000 school year. Questions from the International Survey of Allergies and Asthma in Childhood were used to estimate the prevalence of asthma and wheezing-related illness and associated factors.

RESULTS

Factors independently associated with undiagnosed frequent wheezing versus asymptomatic children included female gender (odds ratio [OR]: 1.45; 95% confidence interval [CI]: 1.35-1.54), current smoking (OR: 2.60; 95% CI: 2.43-2.79), exposure to household smoke (OR: 1.59; 95% CI: 1.50-1.70), low socioeconomic status (OR: 1.52; 95% CI: 1.42-1.63), and African American (OR: 1.25; 95% CI: 1.15-1.34), Native American (OR: 1.35; 95% CI: 1.11-1.62), and Mexican American (OR: 1.32; 95% CI: 1.17-1.48) race/ethnicity. Urban residence showed a weak negative association (OR: 0.91; 95% CI: 0.85-0.96). A similar pattern of results was observed for analyses comparing odds of undiagnosed frequent wheeze versus diagnosed asthmatics. Report of allergies was less likely in frequent wheezers (70%) compared with diagnosed asthmatics (86%), but much higher than in asymptomatic children (36%). Thirty-three percent of children with undiagnosed frequent wheezing reported 1 or more physician visits in the last year for wheezing or breathing problems compared with 71% of children with diagnosed asthma, and 4% in asymptomatic children. The prevalence of any inhaler use in the past 12 months was 12% for undiagnosed frequent wheezers versus 78% for diagnosed asthmatics. The proportion of undiagnosed frequent wheezers with fair or poor self-rated health (23%) was slightly higher than diagnosed asthmatics (20%) and much higher than asymptomatic children (4%).

CONCLUSIONS

In one of the largest adolescent asthma surveys ever reported in the United States, undiagnosed frequent wheezing was independently associated with female gender, current smoking, exposure to household smoke, low socioeconomic status, allergies, and African American, Native American, and Mexican American race/ethnicity. Children with undiagnosed frequent wheezing were not receiving adequate health care for their asthma-like illness. Clinicians who treat adolescents should consider asking adolescents specifically about wheezing. This information may assist primary care physicians in identifying children with undiagnosed asthma in need of treatment.

Lung function and symptom perception in children with asthma and their parents

A large proportion of children with asthma are managed without recourse to specialized care, and treatment decisions are based solely on symptoms as reported by the children and their parents. We investigated 90 school-age children with the diagnosis of asthma and their accompanying parent to evaluate whether we can obtain better information by using three different means of asking for asthma symptoms: a questionnaire for children (QSR(children)), "smilies," and a visual analogue scale for children (VAS(children)). Furthermore, we analyzed the relationship between these symptom reports and lung function results. Finally, we attempted to determine whether performing a lung function test contributes relevant information toward improving asthma management. Multiple linear regression adjusted for age and gender showed a significant relationship between VAS for children and forced expiratory volume in 1 sec (FEV(1)) (P = 0.047) and maximal expiratory flow at 50% of forced vital capacity (MEF(50)) (P = 0.037). Neither age, gender, QSR for children, "smilies for children" nor all the parents' scores showed a significant association with lung function measurement in the regression model. Subgroup analysis with Spearman's rank correlation coefficients by age group revealed significant correlation in children <10 years between VAS for children, QSR for parents, smilies for parents, and the lung function parameters FEV(1), and MEF(50). Above age 10 years there was no correlation at all, with the accuracy correlation ranging from -0.04 to +0.21. Our data demonstrate that reported symptoms do not reliably correlate with lung function results in asthmatic children and the childrens' parents, and correlation is dependent on the instrument used for symptom evaluation. In children, the VAS, and in parents, the QSR were the most valuable means of obtaining best information on asthma symptoms. This underlines the importance of supplementing information on asthma symptoms with lung function measurements to more reliably assess the severity of asthma.

A study of the association between exercise-induced wheeze and exercise versus methacholine-induced bronchoconstriction in adolescents

Among asthmatics, exercise-induced wheeze (EIW) is a frequent symptom, and 40-77% of asthmatics demonstrate exercise-induced bronchoconstriction (EIB). In the North-Trøndelag population-based survey of 8,571 adolescents (YOUNG-HUNT), 26% reported wheeze during the previous 12 months (current wheeze). Of those subjects, 50% reported EIW. The aim of the present study was to investigate the association between EIW and EIB in randomly selected adolescents with EIW as the only or predominant asthma-like symptom, and to relate our findings to results from methacholine bronchoprovocation tests (MT) and measurements of exhaled nitric oxide (ENO). Sixty-three subjects with current wheeze induced by exercise, but not by allergen exposure, were investigated using a treadmill exercise test (ET) and measurements of ENO. Fifty-eight subjects completed a MT on a separate study day. EIB was defined as a fall of >or= 10% in the forced expiratory volume in 1 second (FEV1) after exercise (DeltaFEV1%ex). Twenty-one subjects (33%) had EIB and 33 (57%) had a positive MT. The degree of reported dyspnea during the ET was not correlated to the DeltaFEV1%ex. The correlation between EIB and methacholine-induced bronchoconstriction (MIB) was poor, and the DeltaFEV1%ex was more pronounced in smokers than in non-smokers. Moreover, ENO was not increased in subjects with positive vs. negative ET. Hence, EIW, when reported as the only or predominant asthma-like symptom, was linked to EIB in only one-third of the patients. We conclude that EIW is a poor predictor of EIB in epidemiological studies. The poor correlation between EIB and MIB indicates that these two tests measure different mechanisms of bronchial hyper-responsiveness.

Relationship between asthma medication and antibiotic use

STUDY OBJECTIVES

Increasing morbidity due to asthma and antimicrobial resistance among human pathogens are both major public-health concerns. Numerous studies describe the overuse of antibiotics in general populations and underuse of anti-inflammatory medications by asthmatic patients. However, little is known about the relationship between asthma medication and antibiotic use in asthmatics. Specifically, we tested the hypothesis that higher use of bronchodilator and anti-inflammatory medication by asthmatics, as a marker of problematic asthma, is associated with greater antibiotic use. We also test the hypothesis that physicians who are low prescribers of anti-inflammatory medications are high prescribers of antibiotics.

DESIGN

We conducted a retrospective cohort study evaluating asthma medication and antibiotic use by children and adults with asthma and the prescribing of these medications by primary-care physicians.

SETTING/PATIENTS

Subjects were continuously enrolled asthma patients aged 6 to 55 years receiving care in an urban, group-model, health maintenance organization.

INTERVENTIONS

None.

MEASUREMENT AND RESULTS

Main outcome measures were (1) antibiotic use by asthmatics stratified by low, moderate, and high bronchodilator use; (2) antibiotic use by asthmatics stratified by no, intermittent, and long-term anti-inflammatory use; and (3) correlation between physician-level anti-inflammatory agent to bronchodilator ratio (AIF:BD) and their rate of antibiotic prescribing. We found that (1) high bronchodilator users received 1.72 antibiotics per person-year (95% confidence interval [CI], 1.62 to 1.83), whereas low bronchodilator users received 1.23 antibiotics per person-year (95% CI, 1.19 to 1.27; p < 0.0001); (2) long-term users of anti-inflammatory agents received 1.85 antibiotics per person-year (95% CI, 1.76 to 1.95), whereas those not receiving an anti-inflammatory agent received 0.95 antibiotics per person-year (95% CI, 0.90 to 1.00; p < 0.0001); and (3) despite variations in physician AIF:BDs and antibiotic prescribing, respectively, these measures were not correlated.

CONCLUSIONS

Antibiotic use and asthma medication use are positively associated in a cohort of asthma patients. Greater effort is needed to define the appropriate role of antibiotics in asthma management.

[Chronic cough in children: etiology and decision trees]

Recurrent or chronic cough can be the symptom of a worrying condition which must be diagnosed without delay (cystic fibrosis, asthma, bronchial foreign body, bronchiectasis). Investigation of recurrent or chronic cough is based on simple principles: careful history-taking concerning the characteristics of the cough, full clinical examination to look for any associated symptoms, and auxological assessment to detect any interruption in weight increase. Only when this initial evaluation has been carried out can complementary investigations be sought. Ordinary respiratory infections that are part of the building up of immunity are predominant in coughs of children aged under 6 years and are aggravated by deleterious factors such as passive exposure to tobacco, early introduction to communal life, and urban pollution. We describe the most frequent causes of cough and their frequency according to the age of the child.

Increased incidence of asthmalike symptoms in girls who become overweight or obese during the school years

The possibility of a causal relationship is suggested by recent concomitant increases in the prevalence of obesity and asthma. In a general population sample, prevalence and incidence of asthma symptoms, skin tests, and body mass index (BMI) were ascertained at mean ages of 6.3 (n = 688) and 10.9 (n = 600) yr. Lung function, bronchodilator responsiveness, and daily peak flow variability were measured at 11 yr of age. There was no association between BMI at age 6 and wheezing prevalence at any age. Females, but not males, who were overweight or obese at 11 yr of age were more likely to have current wheezing at ages 11 and 13 but not at ages 6 or 8. This effect was strongest among females beginning puberty before the age of 11. Females who became overweight or obese between 6 and 11 yr of age were 7 times more likely to develop new asthma symptoms at age 11 or 13 (p = 0.0002); at age 11 their peak flow variability and bronchodilator responsiveness were significantly more likely to be increased. In females, becoming overweight or obese between 6 and 11 yr of age increases the risk of developing new asthma symptoms and increased bronchial responsiveness during the early adolescent period.

Asthma and allergy in Russian and Norwegian schoolchildren: results from two questionnaire-based studies in the Kola Peninsula, Russia, and northern Norway

BACKGROUND

Previous studies have shown that the prevalence of asthma and allergy in children is lower in Eastern than Western Europe.

METHODS

We have compared the prevalence of asthma, respiratory symptoms, allergic rhinoconjunctivitis, and atopic dermatitis in schoolchildren aged 7-13 years in a questionnaire-based study conducted in the city of Nikel on the Kola Peninsula, Russia, in 1994 (n = 1143) and another conducted in northern Norway in 1995 (n = 8676).

RESULTS

The prevalence of diagnosed asthma was 5.1% in Russian children and 8.6% in Norwegian children; RR =0.58 (95% CI: 0.44-0.76). The prevalence of all respiratory symptoms was higher in Russian children. The prevalence of allergic rhinoconjunctivitis was 16.9%, in Russian children and 22.1%, in Norwegian children: RR =0.74 (95% CI: 0.65-0.85). The prevalence of atopic dermatitis was 7.4% in Russian children and 19.7% in Norwegian children; RR=0.38 (95% CI: 0.31-0.46).

CONCLUSIONS

We conclude that the prevalence of diagnosed asthma, allergic rhinoconjunctivitis, and atopic dermatitis was higher in Norwegian than Russian schoolchildren. The higher prevalence of respiratory symptoms in Russian children probably reflects a higher prevalence of undiagnosed, nonallergic asthma.

Prevalence of bronchial asthma and allergic rhinitis in Istanbul school children

The aim of this study was to determine the prevalence of asthma, allergic rhinitis and their related symptoms in Istanbul and to investigate the effect of socioeconomic status on the prevalence of asthma and allergic rhinitis and whether there are differences between the prevalence of childhood asthma in the same and different regions as found in previous studies and our own. The study period was the 1996-1997 school year in three primary schools in Istanbul. For proportional representation of high, middle, and low socioeconomic levels, the schools were selected from three different regions of Istanbul. A translated version of the International Study of Asthma and Allergies in Childhood (ISAAC) was used. The questionnaire was distributed to the parents of 2600 students aged 6-15 years. All of the 2276 children whose parents responded were included in the survey. The overall cumulative and current prevalences of wheezing were 13.7 and 7.2% respectively and the overall cumulative prevalence of allergic rhinitis was 17.6%. There was no statistically significant difference between asthmatics and non-asthmatics by sex, socioeconomic status and passive smoking. Family history of atopy was found to be significantly higher in asthmatics. Although there are differences in the results of studies concerning the prevalence of asthma and allergic rhinitis not only between different countries but also between different regions of the same city, by using a standardized international method, the actual values may be obtained.

Urinary eosinophil protein X in children: the relationship to asthma and atopy and normal values

BACKGROUND

In epidemiologic studies, it may be difficult to identify children with bronchial asthma. Since this is the most common chronic respiratory disease in childhood, and its prevalence is still increasing, reliable methods for identification of asthmatic children are required. This study evaluates the use of urinary eosinophil protein X (U-EPX) in epidemiologic studies in identifying atopic and asthmatic children.

METHODS

U-EPX was measured in 877 Austrian schoolchildren. The skin prick test (SPT) was performed with eight common aeroallergens, and established questionnaires were used to assess respiratory symptoms.

RESULTS

Of our cohort, 2.8% reported physician-diagnosed asthma, 5.1% reported wheezing within the last 12 months, and 24.1% were found to be atopic. In children with physician-diagnosed asthma, as well as in atopic children (positive SPT), median U-EPX levels were significantly higher than in healthy subjects (142.8 and 89.6 vs 63.9 microg/mmol creatinine, P<0.0001 and P<0.0001, respectively). In addition, perennial sensitization to inhalant allergens resulted in higher U-EPX levels than did seasonal sensitization. The odds ratio for U-EPX levels over the 90th percentile was significantly elevated for asthma, for wheezing, for nocturnal cough, and for breathlessness at exercise, as well as for seasonal and perennial sensitization. Pulmonary function was negatively related to U-EPX levels.

CONCLUSIONS

Measurement of U-EPX, which can be obtained easily, may be helpful in diagnosing both asthma and atopy in children. However, there is a great overlap between controls and symptomatics, a fact which reduces the sensitivity of U-EPX in determination of the prevalence of asthma in epidemiologic studies.

Prescribing patterns for asthma by general practitioners in six European countries

To assess the level of concordance with international consensus on asthma management, we compared primary care prescribing patterns for asthma in different European countries. A prospective study of prescription items with an associated diagnostic label of asthma in patient consultations with a total of 235 general practitioners (GPs) from Belgium, England, Ireland, Italy, Northern Ireland, Portugal, Scotland and Spain was performed. A total of 101,544 consecutive consultations were recorded in autumns 1994 and 1995 of which 3595 (3.5%) were for patients with asthma and 3243 (3.2%) were for patients receiving a prescription for asthma. Overall, asthma consultations varied from 1.8% in Italy to 5.8% in Ireland (mean 3.4%, SD 1.6). Prescribed inhaled medications for children varied from 72% of the total asthma prescriptions in Ireland and Portugal to 82% in Northern Ireland (mean 79%, SD 8.1) and for adults 55% in Italy to 85% in Spain (mean 70%, SD 10). Inhaled corticosteroid usage for adults varied from 14% in Italy to 31% in Northern Ireland (mean 24%, SD 6.4). For children, beta2-agonist use varied from 24% in Italy to 67% in Spain (mean 45%, SD 13). Despite publication of international guidelines for the management of asthma, inter-country prescribing practices vary considerably and could be improved. The frequency of use of asthma as a diagnostic label also varies markedly.