Incidence rates and risk factors for asthma among school children: a 2-year follow-up report from the obstructive lung disease in Northern Sweden (OLIN) studies

The impact of indoor pollution on asthma-related outcomes: A systematic review for the EAACI guidelines on environmental science for allergic diseases and asthma

Systematic review using GRADE of the impact of exposure to volatile organic compounds (VOCs), cleaning agents, mould/damp, pesticides on the risk of (i) new-onset asthma (incidence) and (ii) adverse asthma-related outcomes (impact). MEDLINE, EMBASE and Web of Science were searched for indoor pollutant exposure studies reporting on new-onset asthma and critical and important asthma-related outcomes. Ninety four studies were included: 11 for VOCs (7 for incidenceand 4 for impact), 25 for cleaning agents (7 for incidenceand 8 for impact), 48 for damp/mould (26 for incidence and 22 for impact) and 10 for pesticides (8 for incidence and 2 for impact). Exposure to damp/mould increases the risk of new-onset wheeze (moderate certainty evidence). Exposure to cleaning agents may be associated with a higher risk of new-onset asthma and with asthma severity (low level of certainty). Exposure to pesticides and VOCs may increase the risk of new-onset asthma (very low certainty evidence). The impact on asthma-related outcomes of all major indoor pollutants is uncertain. As the level of certainty is low or very low for most of the available evidence on the impact of indoor pollutants on asthma-related outcomes more rigorous research in the field is warranted.

Persistent respiratory symptoms associated with post-Covid condition (Long Covid) in children: a systematic review and analysis of current gaps and future perspectives

INTRODUCTION

There is increasing evidence that also children can develop Long Covid. However, there are no specific reviews providing a clear description of reported respiratory symptoms and potential diagnostics.

AREAS COVERED

We performed on PubMed a systematic search of studies conducted on children aged less than 18 years with previous SARS-CoV-2 infection complaining about persistent respiratory symptoms; the aim of our review is to characterize the incidence, pattern and duration of respiratory symptoms after the acute infection in pediatric population.

EXPERT OPINION

Children can develop persisting respiratory symptoms, as documented by several follow-up studies both including or not control groups of non-infected children. However, the methodological variabilities of the analyzed studies does not allow to provide firm conclusions about the rate, type and best diagnostics for children with persistent respiratory symptoms. Future studies should investigate on larger pediatric cohorts the role of noninvasive diagnostics and new biomarkers as well as investigating therapeutic options both during acute infection or when Long Covid has been diagnosed.

Estimated public health benefits of a low-emission zone in Malmö, Sweden

Air pollution is one of the leading causes of morbidity and mortality worldwide. Low-emission zones (LEZ) have been increasingly implemented in cities throughout Europe as a measure to reduce the adverse health effects and premature deaths associated with traffic-related air pollution. In the present study, a health impact analysis was conducted to estimate the effect of a hypothetical LEZ on mortality and morbidity in Malmö, Sweden. Baseline health statistics were gathered from health registers and applied to each resident according to individual-level data on age and/or sex. Concentration-response parameters were derived from current epidemiological literature, specifically meta-analyses. A Gaussian dispersion model (AERMOD) combined with a detailed emission database was used to calculate NO₂ emissions from traffic, which could be applied on an individual-level using data on each person's residential coordinates. The adjusted exposure scenario replaced all vehicles on municipal roads having Euro 5 or lower emission standards with Euro 6 equivalents. This LEZ would, on average, decrease NO₂ concentrations by 13.4%, preventing an estimated 9-26 deaths in Malmö each year. Additionally, 12 respiratory disease hospitalizations, 8 childhood asthma cases, and 9 cases of hypertensive disorders of pregnancy were estimated to be avoided annually. These results suggest that LEZs can effectively improve air quality, reduce greenhouse gas emissions, and safeguard public health.

Pediatric asthma incidence rates in the United States from 1980 to 2017

BACKGROUND

Few studies have examined longitudinal asthma incidence rates (IRs) from a public health surveillance perspective.

OBJECTIVE

Our aim was to calculate descriptive asthma IRs in children over time with consideration for demographics and parental asthma history.

METHODS

Data from 9 US birth cohorts were pooled into 1 population covering the period from 1980 to 2017. The outcome was earliest parental report of a doctor diagnosis of asthma. IRs per 1,000 person-years were calculated.

RESULTS

The racial/ethnic backgrounds of the 6,283 children studied were as follows: 55% European American (EA), 25.5% African American (AA), 9.5% Mexican-Hispanic American (MA) and 8.5% Caribbean-Hispanic American (CA). The average follow-up was 10.4 years (SD = 8.5 years; median = 8.4 years), totaling 65,291 person-years, with 1789 asthma diagnoses yielding a crude IR of 27.5 per 1,000 person-years (95% CI = 26.3-28.8). Age-specific rates were highest among children aged 0 to 4 years, notably from 1995 to 1999, with a decline in EA and MA children in 2000 to 2004 followed by a decline in AA and CA children in 2010 to 2014. Parental asthma history was associated with statistically significantly increased rates. IRs were similar and higher in AA and CA children versus lower but similar in EA and MA children. The differential rates by sex from birth through adolescence principally resulted from a decline in rates among males but relatively stable rates among females.

CONCLUSIONS

US childhood asthma IRs varied dramatically by age, sex, parental asthma history, race/ethnicity, and calendar year. Higher rates in the 0- to 4-year-olds group, particularly among AA/CA males with a parental history of asthma, as well as changes in rates over time and by demographic factors, suggest that asthma is driven by complex interactions between genetic susceptibility and variation in time-dependent environmental and social factors.

Prevalence and clinical presentation of sinusitis in pediatric age group in Aseer, Saudi Arabia

Background:

Paediatric rhinosinusitis is mostly different than that in adults. More frequently, children presented with cough, bad breath, crankiness, low energy, and swelling around the eyes, besides a thick yellow-green nasal or post-nasal discharge. About 5- 13% of childhood viral upper respiratory tract infections may advance to acute rhinosinusitis, with some of them developing a chronic condition.

Aim:

To assess prevalence and clinical presentation of sinusitis in the paediatric age group in Aseer, Saudi Arabia.

Methodology:

A retrospective record-based study was conducted in Abha Maternity and Children Hospital in Abha city, Saudi Arabia between January 2015 and January 2018. All medical records during the study period for children whose from to 15 years old attended the hospital and diagnosed as having sinusitis were included.

Results:

The study included 100 children with complete files whose ages ranged from less than 1 year to up to 13 years old with a mean age of 5.3 4.2 years. Nearly 51% of the children aged 4 years or less and male were 53 (53%). Past history for chronic rhinosinusitis (CRS) was positive among 30 children. Regarding clinical presentations of rhinosinusitis (RS) as reported by the children caregivers, fever was the most reported complaint (50%) followed by red eye (44%), ringing nose (42%), cough (41%) and headache (36%). Mucous culture was positive among 58 cases. The most isolated pathogens were streptococcus pneumoniae (45.6%), Haemophilis influenza (24.6%).

Conclusions:

In conclusion, the study revealed that CRS is a common disease in children at different ages, especially, maxillary and frontal sinuses. In most of the cases, medical treatment is highly appreciated; though, surgical intervention may be needed in a small percentage.

Health Impacts from Ambient Particle Exposure in Southern Sweden

A health impact assessment (HIA) is an important tool for making informed decisions regarding the design and evaluation of environmental interventions. In this study, we performed a quantitative HIA for the population of Scania (1,247,993), the southernmost county in Sweden, in 2016. The impact of annual mean concentrations of particulate matter with an aerodynamic diameter <2.5 µm (PM_2.5), modeled at their home residences for the year 2011, on mortality, asthma, dementia, autism spectrum disorders, preeclampsia and low birth weight (LBW) was explored. Concentration–response (C-R) functions were taken from epidemiological studies reporting meta-analyses when available, and otherwise from single epidemiological studies. The average level of PM_2.5 experienced by the study population was 11.88 µg/m³. The PM_2.5 exposure was estimated to cause 9–11% of cases of LBW and 6% of deaths from natural causes. Locally produced PM_2.5 alone contributed to 2–9% of the cases of diseases and disorders investigated. Reducing concentrations to a maximum of 10 µg/m³ would, according to our estimations, reduce mortality by 3% and reduce cases of LBW by 2%. Further analyses of separate emission sources’ distinct effects were also presented. Reduction of air pollution levels in the study area would, as expected, have a substantial effect on both mortality and adverse health outcomes. Reductions should be aimed for by local authorities and on national and even international levels.

Burden of disease attributable to second-hand smoke exposure: A systematic review

Our aim was to provide a systematic review of studies on the burden of disease due to second-hand smoke (SHS) exposure, reviewing methods, exposure assessment, diseases causally linked to SHS, health outcomes, and estimates available to date. A literature review of studies on the burden of disease from SHS exposure, available in PubMed and SCOPUS, published 2007-2018 in English language, was carried out following the PRISMA recommendations. Overall, 588 studies were first identified, and 94 were eligible. Seventy-two studies were included in the systematic review. Most of them were based on the comparative risk assessment approach, assessing SHS exposure using mainly surveys on exposure at home/workplaces. Diseases more frequently studied were: lung cancer, ischemic heart disease, stroke, chronic obstructive pulmonary disease, asthma and breast cancer in adults; lower respiratory tract infection, otitis media, asthma, sudden infant death syndrome and low birth weight in children. The SHS exposure assessment and the reported population attributable fractions (PAF) were largely heterogeneous. As an example, the PAF from lung cancer varied between 0.6% and 20.5%. Moreover, PAF were estimated applying relative risks and SHS exposures with no consistent definitions or with different age classes. The research gap on the SHS exposure burden is shrinking. However, estimates are not yet available for a number of countries, particularly the Middle Eastern and African countries, and not all diseases with the strongest evidence of causation, such as sudden infant death syndrome, have been explored. Moreover, in some cases the applied methodology revealed relatively low quality of data.

History of allergic rhinitis and risk of asthma; a systematic review and meta-analysis

Background

Allergic rhinitis has been suspected to be a risk factor for asthma in several studies but this association is not firmly established. The objective of this study was to synthesize the evidence of the association between allergic rhinitis and the risk of asthma through a systematic review and meta-analysis.

Methods

We performed a search in Medline, Scopus, ISI Proceedings databases and other databases from inception until February 2019, followed by manual search to identify potentially relevant case-control and cohort studies that reported relative risk estimates and confidence intervals of the association between allergic rhinitis and asthma. Cross-sectional studies were excluded. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using fixed and random effects models and quality of studies was assessed through a modified version of the Newcastle-Ottawa scale.

Results

Twenty-nine eligible studies, 22 cohort and 7 case-control studies, with a total of 274489 subjects, were included in the meta-analysis. The results show that history of allergic rhinitis is significantly associated with the occurrence of asthma (OR = 3.82; 95% CI: 2.92–4.99). European studies showed a stronger association (OR = 4.35; (95% CI: 3.12–6.06) than non-European studies (OR = 2.75; 95% CI: 2.16–3.50), and case-control studies showed a stronger association (OR = 4.71; 95% CI: 3.58–6.17) than cohort studies (OR = 3.42; 95% CI: 2.60–4.50).

Conclusions

This meta-analysis shows that allergic rhinitis is strongly associated with asthma. Further prospective studies on the effect of treatment of allergic rhinitis on the development of asthma are needed. Relief of airway allergic manifestations may need dual control of allergic rhinitis and asthma.

Registration

PROSPERO database with registration number CRD42017055156.

Infant milk-feeding practices and food allergies, allergic rhinitis, atopic dermatitis, and asthma throughout the life span: a systematic review

BACKGROUND

During the Pregnancy and Birth to 24 Months Project, the USDA and Department of Health and Human Services initiated a review of evidence on diet and health in these populations.

OBJECTIVES

The aim of these systematic reviews was to examine the relation of 1) never versus ever feeding human milk, 2) shorter versus longer durations of any human milk feeding, 3) shorter versus longer durations of exclusive human milk feeding prior to infant formula introduction, 4) feeding a lower versus higher intensity of human milk to mixed-fed infants, and 5) feeding a higher intensity of human milk by bottle versus breast with food allergies, allergic rhinitis, atopic dermatitis, and asthma.

METHODS

The Nutrition Evidence Systematic Review team conducted systematic reviews with external experts. We searched CINAHL, Cochrane, Embase, and PubMed for articles published between January 1980 and March 2016, dual-screened the results according to predetermined criteria, extracted data from and assessed the risk of bias for each included study, qualitatively synthesized the evidence, developed conclusion statements, and graded the strength of the evidence.

RESULTS

The systematic reviews numbered 1-5 above included 44, 35, 1, 0, and 0 articles, respectively. Moderate, mostly observational, evidence suggests that 1) never versus ever being fed human milk is associated with higher risk of childhood asthma, and 2) among children and adolescents who were fed human milk as infants, shorter versus longer durations of any human milk feeding are associated with higher risk of asthma. Limited evidence does not suggest associations between 1) never versus ever being fed human milk and atopic dermatitis in childhood or 2) the duration of any human milk feeding and allergic rhinitis and atopic dermatitis in childhood.

CONCLUSIONS

Moderate evidence suggests that feeding human milk for short durations or not at all is associated with higher childhood asthma risk. Evidence on food allergies, allergic rhinitis, and atopic dermatitis is limited.

Estimated health benefits of exhaust free transport in the city of Malmö, Southern Sweden

Air pollution is responsible for one in eight premature deaths worldwide, and thereby a major threat to human health. Health impact assessments of hypothetic changes in air pollution concentrations can be used as a mean of assessing the health impacts of policy, plans and projects, and support decision-makers in choices to prevent disease. The aim of this study was to estimate health impacts attributable to a hypothetical decrease in air pollution concentrations in the city of Malmö in Southern Sweden corresponding to a policy on-road transportations without tail-pipe emissions in the municipality. We used air pollution data modelled for each of the 326,092 inhabitants in Malmö by a Gaussian dispersion model combined with an emission database with >40,000 sources. The dispersion model calculates Nitrogen Oxides (NO_x) (later transformed into Nitrogen Dioxide (NO₂)) and particulate matter with an aerodynamic diameter < 2.5 μg/m³ (PM_2.5) with high spatial and temporal resolution (85 m and 1 h, respectively). The average individual reduction was 5.1 (ranging from 0.6 to 11.8) μg/m³ in NO_2, which would prevent 55 (2% of all deaths) to 93 (4%) deaths annually, depending on dose-response function used. Furthermore, we estimate that the NO₂ reduction would result in 21 (6%) fewer cases of incident asthma in children, 95 (10%) fewer children with bronchitis every year, 30 (1%) fewer hospital admissions for respiratory disease, 87(4%) fewer dementia cases, and 11(11%) fewer cases of preeclampsia every year. The average reduction in PM_2.5 of 0.6 (ranging from 0.1 till 1.7) μg/m³ would mean that 2729 (0.3%) work days would not be lost due to sick-days and that there would be 16,472 fewer restricted activity days (0.3%) that year had all on-road transportations been without tail-pipe emissions. Even though the estimates are sensitive to the dose-response functions used and to exposure misclassification errors, even the most conservative estimate of the number of prevented deaths is 7 times larger than the annual traffic fatalities in Malmö, indicating a substantial possibility to reduce the health burden attributed to tail-pipe emissions in the study area.

Sex differences in asthma in swimmers and tennis players

BACKGROUND

Elite athletes, independent of sport, have increased risk of developing asthma, but little is known about sex difference among adolescent athletes.

OBJECTIVE

To investigate and compare sex-related differences according to symptoms and treatment of asthma, allergy, and health among elite athletes and a reference group.

METHODS

Adolescent elite swimmers (n = 101), tennis players (n = 86), and a reference group (n = 1,628) responded to a questionnaire about respiratory symptoms, allergy, health behavior, psychosomatic symptoms, self- esteem, and well-being. The athletes performed a mannitol provocation and a sport-specific exercise provocation. Atopy was assessed by skin prick tests, and fractional exhaled nitric oxide was measured.

RESULTS

The females reported more asthma symptoms than the males in both the reference group (29.1% vs 22.3%) and the athlete group (56.4% vs 40.2%). However, no significant differences were found in physician-diagnosed asthma or treatment with inhaled corticosteroids. More female athletes had a positive mannitol provocation result (48.7% vs 35.8% in male athletes), and more female swimmers had a positive exercise provocation result (15.1% vs 7.7% in male swimmers). The females in all groups had more psychosomatic symptoms compared with the respective males, and the males in the reference group reported higher self-esteem and felt more well-being compared with the reference group females.

CONCLUSION

Overall, we found a higher prevalence of asthma symptoms in the females. However, the frequency of physician-diagnosed asthma and the prescription of inhaled corticosteroids were the same in both sexes. This finding demonstrates an insufficient diagnosis of asthma in females.

Relevance of specific IgE antibody titer to the prevalence, severity, and persistence of asthma among 19-year-olds in northern Sweden

BACKGROUND

Although sensitization to indoor allergens is strongly associated with asthma, there are questions as to how this relates to asthma symptoms.

OBJECTIVE

We sought to study the relevance of IgE antibodies to cat and dog allergens in an area in which (1) the climate discourages cockroach, fungal, and mite growth and (2) dander allergens are known to be present in schools and houses without animals.

METHODS

IgE to 8 allergens was tested in 963 sera from a population-based study on 19-year-olds, and associations with asthma symptoms, diagnosis, and treatment were examined. In positive sera IgE to specific cat and dog allergens was also assayed.

RESULTS

IgE specific for animal dander had the highest prevalence and strongest relationship to asthma diagnosis. Furthermore, asthma severity, as judged by the frequency of symptoms and use of treatment, was directly associated with the titer of IgE antibodies to animal dander. Among the 103 subjects who had current asthma at age 19 years, 50 had asthma before age 12 years. Among those 50, the odds ratios for asthma related to any IgE antibodies to animal dander or high-titer IgE antibodies (≥17.5 IU/mL) were 9.2 (95% CI, 4.9-17) and 13 (95% CI, 6.9-25), respectively. In multivariable analysis IgE antibodies to Fel d 1 and Can f 5 were each associated with current asthma.

CONCLUSION

High-titer IgE antibodies to cat and dog allergens were strongly associated with the diagnosis, severity, and persistence of asthma; however, a large proportion of patients with current asthma did not live in a house with a cat or dog.

Environmental risk factors related to the incidence of wheeze and asthma in adolescence

BACKGROUND

Asthma is common among adolescents, but there are few population-based studies on the risk factors for incident asthma and wheeze at this age group.

OBJECTIVE

To study risk factors for incident asthma and wheeze in adolescence.

METHOD

Within the Obstructive Lung Disease In Northern Sweden (OLIN) studies, a cohort of 3430 school children (age 7-8 year) was recruited in 1996. In the present study, this cohort was followed from age 12-19 year. At baseline (age 12 year), 3151 participated and skin prick tests (SPT) were performed. The cohort was resurveyed annually, and risk factors for the cumulative incidence of asthma and wheeze from age 12-19 year were analysed using multivariate Cox regression.

RESULTS

Female sex (wheeze: HR 1.4 95%CI 1.2-1.6; asthma: HR 1.8 95%CI 1.2-2.5) and a positive SPT to cat, dog or horse at baseline (wheeze: HR 1.6 95%CI 1.2-2.1; asthma: HR 2.3 95%CI 1.4-4.0) were significantly associated with the cumulative incidence of wheeze and asthma. Increasing numbers of siblings were inversely related to the incidence of wheeze (HR 0.9 95%CI 0.8-0.97) and asthma (HR 0.8 95%CI 0.7-0.97). Parental asthma was related to the incidence of asthma (HR 1.8 95%CI 1.2-2.6) while ever smoking (HR 2.0 95%CI 1.6-2.4) and house dampness (HR 1.3 95%CI 1.1-1.6) were risk factors for the incidence of wheeze. Maternal ETS exposure increased the risk of incident asthma in non-sensitized subjects (HR 1.9 95%CI 1.0-3.7).

CONCLUSION AND CLINICAL RELEVANCE

Several environmental risk factors related to the incidence of asthma and wheeze in adolescence were identified and may be possible targets for intervention and prevention.

Clinical consensus statement: pediatric chronic rhinosinusitis

OBJECTIVE

To develop a clinical consensus statement on the optimal diagnosis and management of pediatric chronic rhinosinusitis (PCRS).

METHODS

A representative 9-member panel of otolaryngologists with no relevant conflicts of interest was assembled to consider opportunities to optimize the diagnosis and management of PCRS. A working definition of PCRS and the scope of pertinent otolaryngologic practice were first established. Patients of ages 6 months to 18 years without craniofacial syndromes or immunodeficiency were defined as the targeted population of interest. A modified Delphi method was then used to distill expert opinion into clinical statements that met a standardized definition of consensus.

RESULTS

After 2 iterative Delphi method surveys, 22 statements met the standardized definition of consensus while 12 statements did not. Four statements were omitted due to redundancy. The clinical statements were grouped into 4 categories for presentation and discussion: (1) definition and diagnosis of PCRS, (2) medical treatment of PCRS, (3) adenoiditis/adenoidectomy, and (4) endoscopic sinus surgery (ESS)/turbinoplasty.

CONCLUSION

Expert panel consensus may provide helpful information for the otolaryngologist in the diagnosis and management of PCRS in uncomplicated pediatric patients.

Birth weight and childhood wheezing disorders: a systematic review and meta-analysis

BACKGROUND

Previous observational studies have claimed that birth weight and childhood wheezing disorders are associated although the results remained inconsistent. One systematic review and two systematic reviews that included meta-analyses reported inconsistent results. We aimed to conduct a systematic review and meta-analysis to investigate this.

METHODS

An online search of published papers linking childhood asthma and wheezing disorders with birth weight up to February 2014 was carried out using EMBASE and Medline medical research databases. Summary ORs were estimated using random-effects models. Subgroup meta-analyses were performed to assess the robustness of risk associations and between-study heterogeneity.

RESULTS

A total of 37 studies comprising 1,71, 737 participants were included in our meta-analysis. The unadjusted summary ORs for risk of childhood wheezing disorders associated with low birth weight (<2.5 kg) were 1.60 (95% CI 1.39 to 1.85, p<0.001) and 1.37 (95% CI 1.05 to 1.79, p=0.02) when compared with ≥2.5 and 2.5-4.0 kg birthweight groups, respectively. The overall summary OR for high birth weight (>4 kg) as compared to the 2.5-4.0 kg birthweight group was 1.02 (95% CI 0.99 to 1.04, p=0.13). There was substantial heterogeneity in the unadjusted low birth weight risk estimates which was not accounted for by predefined study characteristics. There was no significant heterogeneity in the high birth weight risk estimates. There was some evidence of funnel plot asymmetry and small study effects in the low birth weight (2.5 vs ≥2.5 kg and <2.5 vs 2.5-4 kg) OR estimates.

CONCLUSIONS

Our results suggest that low birth (<2.5 kg) is an independent risk factor for wheezing disorders during childhood and adolescence although there was substantial heterogeneity among the risk estimates. However, we found no significant association of high birth weight with wheezing disorders.

Increasing prevalence of asthma, allergic rhinoconjunctivitis and eczema among schoolchildren: three surveys during the period 1985-2008

AIM

The prevalence of asthma, allergic rhinoconjunctivitis (AR) and eczema among children has increased worldwide in the last four decades, but recent studies disagree as to whether the prevalence is continuing to rise or is levelling off or declining. The aim of this study was to assess time trends in a subarctic population.

METHODS

A cross-sectional, questionnaire-based survey was carried out in 2008 among children aged 7-14 years in randomly selected schools in Nordland County, Norway (n = 4150). The results are compared with results from identical studies in 1985 (n = 4870) and 1995 (n = 4456).

RESULTS

The main findings were an increasing prevalence of asthma ever (7.3% in 1985 to 17.6% in 2008, p for trend < 0.001) and AR ever (15.9% in 1985 to 24.5% in 2008, p for trend < 0.001), while the prevalence of eczema ever, after an increase between 1985 and 1995, remained unchanged in the last time period. The prevalence of current disease doubled and trebled between 1995 and 2008 for all three diseases.

CONCLUSION

A repeated cross-sectional survey between 1985 and 2008 documented an increasing prevalence of asthma ever and AR ever among schoolchildren (7-14 years), together with a considerably increase in current asthma, AR and eczema between 1995 and 2008.

Residential dampness and molds and the risk of developing asthma: a systematic review and meta-analysis

CONTEXT

Studies from different geographical regions have assessed the relations between indoor dampness and mold problems and the risk of asthma, but the evidence has been inconclusive.

OBJECTIVE

To assess the relations between indicators of indoor dampness and mold problems and the risk of developing new asthma, and to investigate whether such relations differ according to the type of exposure.

DATA SOURCES

A systematic literature search of PubMed database from 1990 through March 2012 and the reference lists of recent reviews and of relevant articles identified in our search.

STUDY SELECTION

Cohort/longitudinal and incident case-control studies assessing the relation between mold/dampness and new asthma were included.

DATA EXTRACTION

Three authors independently evaluated eligible articles and extracted relevant information using a structured form.

SYNTHESIS

SIXTEEN STUDIES WERE INCLUDED: 11 cohort and 5 incident case-control studies. The summary effect estimates (EE) based on the highest and lowest estimates for the relation between any exposure and onset of asthma were for the highest estimates 1.48 (95% confidence interval [CI] 1.23-1.78, random-effects model, Q-statistic 38.75 (16), P = 0.001) ; and for the lowest estimates: 1.27 (95% CI 1.06-1.53, random-effects model, Q-statistic 38.12 (16), P = 0.000) [corrected].The summary effect estimates were significantly elevated for dampness (fixed-effects model: EE 1.33, 95% CI 1.12-1.56, Q-statistic 8.22 (9), P = 0.413), visible mold (random-effects model; EE 1.29, 95% CI 1.04-1.60, 30.30 (12), P = 0.001), and mold odor (random-effects model; EE 1.73, 95% CI 1.19-2.50, Q-statistics 14.85 (8), P = 0.038), but not for water damage (fixed-effects model; EE 1.12, 95% CI 0.98-1.27). Heterogeneity was observed in the study-specific effect estimates.

CONCLUSION

The evidence indicates that dampness and molds in the home are determinants of developing asthma. The association of the presence of visible mold and especially mold odor to the risk of asthma points towards mold-related causal agents.

The population attributable fraction of asthma among Canadian children

OBJECTIVE

We calculated the population attributable fraction (PAF) of Canadian childhood asthma due to modifiable environmental exposures, in order to estimate their relative contributions to asthma development based on the current literature.

METHODS

We conducted a systematic review to determine Canadian childhood asthma incidence, Canadian prevalence of exposure to airborne pollutants and indoor allergens, and international estimates of the risk of developing physician-diagnosed asthma (PDA) associated with each exposure. Combining risk estimates by meta-analysis where possible, PAF was calculated by the formula: PAF = Attributable risk *Exposure prevalence* 100%/Asthma incidence.

SYNTHESIS

Age-specific Canadian childhood asthma incidence ranged from 2.8%-6.9%. Canadian exposure prevalences were: PM10 16%, PM2.5 7.1%, NO2 25%, environmental tobacco smoke (ETS) 9.0%, cat 22%, dog 12%, mouse 17%, cockroach 9.8%, dust mite 30%, moisture 14% and mould 33%. Relative risk estimates of PDA were: PM10 1.64, PM2.5 1.44, NO2 1.29, ETS 1.40, mouse 1.23, cockroach 1.96, and spanned 1.00 for cat, dog, dust mites, moisture and mould. PAF estimates for incident asthma among preschool children were: PM10 11%, PM2.5 1.6%, NO2 4.0%, ETS 2.9%, mouse 6.5% and cockroach 13%.

CONCLUSIONS

This systematic review suggests contributions to childhood asthma development from exposure to particulates, NO2, ETS, mouse and cockroach. The associations appeared to be more complex for cat, dog and dust mite allergens and more variable for mould and moisture. Additional prospective, population-based studies of childhood asthma development with objectively-measured exposures are needed to further quantify these associations.

A nationwide study of asthma incidence rate and its determinants in Swedish pre-school children

While many studies on asthma prevalence have been published, the number of studies on asthma incidence in pre-school children is limited. In this project, a nationwide sample of pre-school children was followed with the aim of estimating cumulative 5-year asthma incidence and its determinants. Parents of 5,886 children 1-6 years of age, sampled from day-care centres in 62 municipalities all over Sweden, responded in 2002 to a baseline postal questionnaire with questions regarding symptoms indicating possible asthma or atopic conditions, and a number of other variables. In 2007, parents of 4,255 children responded to an almost identical follow-up questionnaire. Of these, the 3,715 children who were free from asthma at baseline constitute the study population for this report. A large number of potential baseline determinants for cumulative 5-year asthma incidence were identified. Of these, food allergy, rhinitis, incomplete asthma diagnosis criteria (wheezing last 12 months, and ever had asthma but no current symptoms), parental rhinitis, parental asthma, age, and eczema, in ranking order of importance, remained significant in multivariate logistic regression analysis. The asthma incidence rate was highly dependent on presence or absence of these variables, the average annual rate ranging from 2/1,000/year in 6-year-olds with no determinants to 154/1,000/year in 1-year-olds with all determinants, corresponding to 11/1,000/year based on the whole study population.

Prenatal and passive smoke exposure and incidence of asthma and wheeze: systematic review and meta-analysis

OBJECTIVES

Exposure to passive smoke is a common and avoidable risk factor for wheeze and asthma in children. Substantial growth in the prospective cohort study evidence base provides an opportunity to generate new and more detailed estimates of the magnitude of the effect. A systematic review and meta-analysis was conducted to provide estimates of the prospective effect of smoking by parents or household members on the risk of wheeze and asthma at different stages of childhood.

METHODS

We systematically searched Medline, Embase, and conference abstracts to identify cohort studies of the incidence of asthma or wheeze in relation to exposure to prenatal or postnatal maternal, paternal, or household smoking in subjects aged up to 18 years old. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were estimated by using random effects model.

RESULTS

We identified 79 prospective studies. Exposure to pre- or postnatal passive smoke exposure was associated with a 30% to 70% increased risk of incident wheezing (strongest effect from postnatal maternal smoking on wheeze in children aged ≤2 years, OR = 1.70, 95% CI = 1.24-2.35, 4 studies) and a 21% to 85% increase in incident asthma (strongest effect from prenatal maternal smoking on asthma in children aged ≤2 years, OR = 1.85, 95% CI = 1.35-2.53, 5 studies).

CONCLUSIONS

Building upon previous findings, exposure to passive smoking increases the incidence of wheeze and asthma in children and young people by at least 20%. Preventing parental smoking is crucially important to the prevention of asthma.

Positive associations between respiratory outcomes and fungal index in rural inhabitants of a representative sample of French dwellings

Our study aims at estimating exposure to molds at home, based on microbial Volatile Organic Compounds (MVOCs) assessment, and evaluating its effect on respiratory diseases in a representative sample of dwellings. In the framework of a national campaign, indoor pollution was monitored in a sample of the 24 million dwellings of metropolitan France (n=567). 727 subjects answered to a standardized questionnaire on respiratory diseases and had MVOCs sampled in their bedrooms and a fungal index (FI) defined. Among the 431 dwellings with complete data, one out of three was contaminated by molds as assessed by a positive FI: 27.0% in urban, 38.2% in periurban and 34.9% in rural dwellings respectively. Positive associations were observed between fungal index and current asthma (8.6%) and chronic bronchitis-like symptoms (8.4%), especially in rural areas (OR=2.95, 95%CI (1.10; 7.95) and 3.35, 95%CI (1.33; 8.48) respectively). Our study, based on objective assessments of fungal contamination, is in agreement with previous results suggesting mold-related respiratory effects. Moreover associations found among rural population could indicate specific pollution and impact in this environment.

Conventional epidemiology underestimates the incidence of asthma and wheeze-a longitudinal population-based study among teenagers

Background

Because of shifts in the gender ratio and incidence and remission rates of asthma during the teen ages, the methodology of incidence studies among teenagers is important, i.e. if the time intervals between surveys are too long, the incident cases might not be properly identified. The aim was to study the impact of study design on the incidence rates of asthma and wheeze during the teen ages.

Methods

In a study about asthma and allergic diseases within the OLIN studies (Obstructive Lung Disease in northern Sweden), a cohort of school children (n = 3,430) was followed annually by questionnaire from age 8 yrs. In the endpoint survey (age 18 yrs) 2,582 (75% of original responders) participated. Incident cases from age 12-18 yrs were identified by two methods: annual questionnaire reports (AR) and baseline-endpoint surveys only (BE).

Results

The cumulative incidence of asthma and wheeze was significantly higher based on AR compared to BE. Compared to the incidence rates based on all the annual surveys, the calculated average annual rates based on BE were in general lower both among the boys and among the girls. There were no differences between boys and girls in incidence rates of asthma or wheeze during the early teen years. However, from the age of 15 years, the annual incidence rates were significantly or borderline significantly higher among girls than boys. At onset, the additional cases of current asthma identified by AR had significantly less severe asthma than those identified in BE (p < 0.02).

Conclusion

the size of the incidence of asthma and wheeze during the teen ages was influenced by study design. By using the conventional prospective study design with longer follow-up time, the incidence was underestimated.

Direct medical costs of constipation from childhood to early adulthood: a population-based birth cohort study

BACKGROUND

Although direct medical costs for constipation-related medical visits are thought to be high, to date there have been no studies examining whether longitudinal resource use is persistently elevated in children with constipation. Our aim was to estimate the incremental direct medical costs and types of health care use associated with constipation from childhood to early adulthood.

METHODS

A nested case-control study was conducted to evaluate the incremental costs associated with constipation. The original sample consisted of 5718 children in a population-based birth cohort who were born during 1976 to 1982 in Rochester, MN. The cases included individuals who presented to medical facilities with constipation. The controls were matched and randomly selected among all noncases in the sample. Direct medical costs for cases and controls were collected from the time subjects were between 5 and 18 years of age or until the subject emigrated from the community.

RESULTS

We identified 250 cases with a diagnosis of constipation in the birth cohort. Although the mean inpatient costs for cases were $9994 (95% Confidence interval [CI] 2538-37,201) compared with $2391 (95% CI 923-7452) for controls (P = 0.22) during the time period, the mean outpatient costs for cases were $13,927 (95% CI 11,325-16,525) compared with $3448 (95% CI 3771-4621) for controls (P < 0.001) during the same time period. The mean annual number of emergency department visits for cases was 0.66 (95% CI 0.62-0.70) compared with 0.34 (95% CI 0.32-0.35) for controls (P < 0.0001).

CONCLUSIONS

Individuals with constipation have higher medical care use. Outpatient costs and emergency department use were significantly greater for individuals with constipation from childhood to early adulthood.

PVC--as flooring material--and its association with incident asthma in a Swedish child cohort study

The Dampness in Buildings and Health study (DBH) started in the year 2000 in Värmland, Sweden, with a baseline questionnaire sent to all children (n = 14,077) aged 1-6. Five years later, a follow-up questionnaire was sent to the children who were 1-3 years at baseline. A total of 4779 children participated in both the baseline and the follow-up studies and constitute the study population in this cohort study. The aim of this study was to examine the association between exposure to PVC-flooring in the child's and parent's bedroom in homes of children aged 1-3 and the incidence of asthma, rhinitis, and eczema during the following 5-year period. Adjusted analyses showed that the incidence of asthma among children was associated with PVC-flooring in the child's bedroom (AOR 1.52; 95% CI 0.99-2.35) and in the parent's bedroom (1.46; 0.96-2.23). The found risks were on borderline of significance and should therefore be interpreted with caution. There was further a positive relationship between the number of rooms with PVC-flooring and the cumulative incidence of asthma. PVC-flooring was found to be a stronger risk factor for incident asthma in multifamily homes when compared with single-family houses and in smoking families compared with non-smoking families and in women.

PRACTICAL IMPLICATIONS

These longitudinal data from the DBH study found an association between the presence of PVC-flooring in the home and incident asthma in children. However, earlier results from the DBH study have shown that PVC-flooring is one important source for phthalates in indoor dust, and exposure to such phthalates was found to be associated with asthma and allergy among children. This emphasizes the need for prospective studies that focus on the importance of prenatal and neonatal exposure to phthalates in the development of asthma and allergy in children.

Characterization of the asthmatic population of St. Vincent and the Grenadines: asthma severity levels and atopic sensitization

BACKGROUND

The developing country of St. Vincent and the Grenadines (SVG) reported a 4.5-fold increase in wheezing incidence between 1986 and 2002. It is unknown whether aeroallergens play a significant role in asthma in SVG.

OBJECTIVE

The objective of the study is to investigate the importance of aeroallergens and the association between age and persistence of asthma into adulthood. Methods. Subjects were recruited from the National Asthma Clinic. Asthma was diagnosed in 525 participants and severity levels assigned according to the National Heart, Lung, and Blood Institute guidelines. Participants were separated into three age groups [≤6 years (n=176), 7-18 years (n=164), and ≥19 years (n=185)]. Skin testing was performed on 171 participants to dust mite, cat, dog, cockroach, pollens, and mold. Age of asthma onset was obtained.

RESULTS

Persistent asthma was diagnosed in 235 participants (44.8%) and increased with increasing age group (p<.0001). Atopy was identified in 121/171 (70.8%) participants and was significantly higher in persistent asthma (p<.004). A significant positive association was seen between atopy and age group (p<.0004) in participants with intermittent asthma but not in participants with persistent asthma. The most common allergen among the atopic participants was house dust mite (93.4%), followed by cockroach (47.9%). Adult participants reporting asthma onset in adulthood were less atopic than those whose asthma developed ≤18 years of age (p<.05).

CONCLUSIONS

The predominance of asthma with atopy in SVG implicates a role for atopy in the sudden rise in asthma cases. This asthma characteristic and the increase in persistent asthma with age in SVG are similar to those reported in the developed countries.

Asthma and allergic diseases in school children from 1992 to 2007 with incidence data

BACKGROUND

Information about change in the prevalence of asthma and allergic diseases and factors related with these diseases would be beneficial in decreasing the burden of these diseases.

OBJECTIVE

To assess (i) change in prevalence of asthma and allergic diseases; (ii) factors associated with asthma and wheeze; and (iii) incidence of asthma and wheeze.

METHODS

A questionnaire was administered to children aged 7-12 years in first five grades in the same primary school in 1992 (n: 1036), 1997 (n: 738), 2002 (n: 621), and 2007 (n: 422) and filled by the parents. A second survey in 2007 (n: 474, in eight grades) was conducted in the same schoolchildren, 6 months apart, to assess the incidence of asthma and wheeze and the associated factors.

RESULTS

Comparison of 1992, 1997, 2002, and 2007 surveys revealed that prevalence of asthma (8.3%, 9.8%, 6.4%, 3.3%, respectively), wheeze (11.9%, 13.3%, 6.4%, 3.1%, respectively), hay fever (15.4%, 14.1%, 7.2%, 3.1%, respectively), and eczema (4.0%, 4.3%, 1.8%, 1.2%, respectively) were significantly lower in 2002 and 2007 compared with that in 1992. Percentage of passive smoking decreased after 1992 (74.0%, 64.0%, 64.1%, and 65.5%, respectively). Incidence of asthma and wheeze in 2007 surveys were 0.9/100 and 1.1/100, respectively. After the adjustment for age and gender, infection in the past, family atopy, and presence of atopic disease (eczema or hay fever) were associated with asthma and wheeze. Maternal smoking and lack of breast feeding were associated with asthma. Male gender, pet ownership in the past, lack of health insurance coverage, snoring, and wood or coal used as fuel were associated with wheeze.

CONCLUSIONS

Decreased prevalence of asthma and allergic diseases in the last 10 years could be related to decreased rate of passive smoking. Lower socioeconomic status and lack of breast feeding could increase the risk of asthma in children.

The Obstructive Lung Disease in Northern Sweden (OLIN) longitudinal paediatric study I--the first 10 years

BACKGROUND

Prospective studies of asthma and allergic conditions based on the general population are scarce.

AIM

To summarize the methods and main results from a prospective study among school children.

METHODS

In 1996, a cohort of 3525 children aged 7/8 years in Northern Sweden were invited to a questionnaire survey using an expanded ISAAC protocol, and 97% participated. The cohort has been followed up yearly with high participation rate. Skin prick tests were conducted 1996, 2000 and 2006/2007. Allergens in dust from homes and schools have been analyzed. Sub samples have participated in interviews, lung function tests, bronchial hyper reactivity test, and analyses of IgE and IgG antibodies in serum.

RESULTS

The prevalence of asthma was 6% at age 7-8 years and increased by age. The incidence of physician-diagnosed asthma after the age of 7-8 years was around 1/100/year. The prevalence of positive skin prick test increased from 21% at age 7-8 to 30% at age 11-12 years. Remission of allergic sensitization was rare, while asthma remission was 5% yearly. The main risk factor for asthma and allergic sensitization increased in importance with increasing age. Allergic and non-allergic asthma had different risk factor pattern. Environmental risk factors decreased in impact after the age of 7. Avoidance of pets at home did not protect from asthma or allergic sensitization.

CONCLUSION

The study includes important sources of data for further longitudinal analyses that will contribute to the understanding of the development and the nature of asthma and allergic sensitization.

Prevalence, incidence and persistence of anti-asthma medication use in 2- to 29-year-olds: a nationwide prescription study

PURPOSE

The purpose of this study was to examine gender- and age-specific prevalence, incidence, and the type of anti-asthma medications used in the Norwegian population aged 2-29 years during 2005-2007 and to estimate the share of individuals who regularly redeemed medications over a 3-year period.

METHODS

We retrieved data from the nationwide Norwegian Prescription Database for all individuals 2-29 years old (n = 1.7 million) who received anti-asthma medications during 2005-2007. Medications included inhaled short- and long-acting beta(2)-agonists, inhaled corticosteroids, fixed-dose combinations of inhaled beta(2)-agonists and corticosteroids, and leukotriene antagonists.

RESULTS

In 2007, 5.5% (92,074 individuals) of Norwegians aged 2-29 years received anti-asthma medication, and this figure was stable throughout 2005-2007. Prevalence and incidence were higher among males than females but shifted to female dominance during adolescence. The share of anti-asthma medication users who received inhaled corticosteroids was high in preschool children but decreased by age. Conversely, use of inhaled beta(2)-agonists as monotherapy and of fixed combinations increased with age. Fewer than half the individuals were "persistent" to medication treatment for 3 years by redeeming prescriptions regularly (at least once a year).

CONCLUSIONS

In this nationwide study, annual prevalence of anti-asthma medication use was stable during 2005-2007. The gender- and age-specific profile of prevalence and incidence correspond well with other studies. Fewer than half the individuals redeemed prescriptions regularly over 3 years.

What is the lifetime risk of physician-diagnosed asthma in Ontario, Canada?

RATIONALE

Asthma is the most common chronic respiratory disease in Canada. The estimates of risk of developing asthma may help researchers and health planners set research agendas, predict the burden of asthma on society, and target the at-risk population for asthma prevention, management, and control.

OBJECTIVES

To estimate the lifetime risk of physician-diagnosed asthma.

METHODS

All individuals aged 0-79 years living in Ontario, Canada on April 1, 1996 who had not been diagnosed with asthma were monitored for 11 years until March 31, 2007. They were censored when they were diagnosed with asthma, turned age 80 years, or died. The lifetime risk (from birth to age 79 yr) of physician-diagnosed asthma was calculated by a modified survival analysis technique. Results were stratified by sex, rurality, and neighborhood income.

MEASUREMENTS AND MAIN RESULTS

Overall, the lifetime risk of physician-diagnosed asthma was 33.9%. Whereas the overall lifetime risk was higher in females (35.0 vs. 32.9%; P < 0.001), the cumulative risk was higher in males in early years. The lifetime risk was higher in individuals living in urban areas (34.5 vs. 30.1%; P < 0.001) or low-income neighborhoods (35.0% in the lowest income quintile vs. 32.2% in the highest; P < 0.001).

CONCLUSIONS

Our estimated overall lifetime risk indicates that one of every three individuals in Ontario, Canada has physician-diagnosed asthma during one's lifetime.

Health-related quality of life in young adults with asthma

BACKGROUND

The aim was to study health-related quality of life, five years after an intervention study among young adults with asthma.

METHOD

The design was a follow-up study of a cohort of young adults with asthma (n=64) and 248 general population controls. Both groups were investigated at follow-up with a respiratory questionnaire and one generic quality-of-life instrument, and the asthma cohort also completed one-asthma-specific questionnaire. The material was analyzed with multivariate models.

RESULTS

Female gender and low FEV1 at baseline predicted both a decline during follow-up and a low quality of life at follow-up. The asthma cohort and controls scored similarly regarding generic quality of life. However, in the asthma cohort, females scored significantly lower in the physical dimension of the generic instrument, especially in the domain of general health.

CONCLUSIONS

There is an association between low FEV1 and a decline in quality of life among young adults with asthma, i.e. low FEV1 predicts a decline in quality of life during a five-year period. Young females with asthma seem to have lower quality of life compared with young males with asthma.

A pilot asthma incidence surveillance system and case definition: lessons learned

OBJECTIVES

Surveillance for incident asthma in the general population could provide timely information about asthma trends and new, emerging etiologic factors. We sought to determine the feasibility of an asthma incidence surveillance system using voluntary reporting of asthma by outpatient clinics and emergency departments (EDs).

METHODS

Voluntary reporting occurred from July 2002 through June 2006. We classified reported asthma based on a case definition adapted from one developed by the Council of State and Territorial Epidemiologists. We validated the case definition by having pulmonologists review data from participant interviews, medical record abstractions, and pulmonary function test (PFT) results.

RESULTS

The positive predictive value (PPV) of meeting any of the case definition criteria for asthma was 80% to 82%. The criterion of taking at least one rescue and one controller medication had the highest PPV (97% to 100%). Only 7% of people meeting the incident case definition had a PFT documented in their medical record, limiting the usefulness of PFT results for case classification. Compared with pediatric participants, adult participants were more likely to be uninsured and to obtain asthma care at EDs. The surveillance system cost $5129 per enrolled person meeting the incident case definition and was difficult to implement in participating clinics and EDs because asthma reporting was not mandatory and informed consent was necessary.

CONCLUSIONS

The project was useful in evaluating the case definition's validity and in describing the participants' characteristics and health-care use patterns. However, without mandatory reporting laws, reporting of incident asthma in the general population by clinicians is not likely to be a feasible method for asthma surveillance.

Incidence rates of asthma, rhinitis and eczema symptoms and influential factors in young children in Sweden

AIM

To estimate the incidence rates for asthma, rhinitis and eczema symptoms and to investigate the importance of different influential factors for the incidence of these symptoms.

METHODS

The Dampness in Building and Health study commenced in the year 2000 in Värmland, Sweden with a parental questionnaire based on an ISAAC protocol to all children in the age of 1-6 years. Five years later a follow-up questionnaire was sent to the children that were 1-3 years at baseline. In total, 4779 children (response rate = 73%) participated in both surveys and constitute the study population in this cohort study.

RESULTS

The 5-year incidence of doctor-diagnosed asthma was 4.9% (95% CI 4.3-5.3), rhinitis was 5.7% (5.0-6.4) and eczema was 13.4% (12.3-14.5). However, incidence rates strongly depend on the health status of the baseline population. Risk factors for incident asthma were male gender and short period of breast-feeding. Allergic symptoms in parents were also a strong risk factor for incident asthma, as well as for rhinitis and eczema.

CONCLUSION

When comparing incident rates of asthma between different studies it is important to realize that different definitions of the healthy baseline population will give rise to different incident rates.

Exposure to furry pets and the risk of asthma and allergic rhinitis: a meta-analysis

BACKGROUND

Exposure to pets has been implicated as a risk factor for asthma. However, this relation has been difficult to assess in individual studies because of the large potential of selection bias. We sought to examine the association between exposure to furry pets and asthma and allergic rhinitis by means of a meta-analysis.

METHODS

We retrieved studies published in any language by searching systematically Medline (1966-March 2007), Embase, LILACS and ISI Proceedings computerized databases, and by examining manually the references of the original articles and reviews retrieved. We included cohort and case-control studies reporting relative risk estimates and confidence intervals of exposure to cats, dogs and unspecified furry animals and subsequent asthma and allergic rhinitis. We excluded cross-sectional studies and those studies that did not measure exposure but rather sensitization to pets.

RESULTS

Thirty-two studies were included. For asthma, the pooled relative risk related to dog exposure was 1.14 (95% CI 1.01-1.29), that related to exposure to any furry pet was 1.39 (95% CI 1.00-1.95). Among cohort studies, exposure to cats yielded a relative risk of 0.72 (95% CI 0.55-0.93). For rhinitis, the pooled relative risk of exposure to any furry pet was 0.79 (95% CI 0.68-0.93).

CONCLUSIONS

Exposure to cats exerts a slight preventive effect on asthma, an effect that is more pronounced in cohort studies. On the contrary, exposure to dogs increases slightly the risk of asthma. Exposure to furry pets of undermined type is not conclusive. More studies with exact measurement of exposure are needed to elucidate the role of pet exposures in atopic diseases.

Reduced risk of physician-diagnosed asthma among children dwelling in a farming environment

BACKGROUND AND OBJECTIVE

Living in a farm environment has been reported to be associated with lower prevalence of asthma, based on the results of cross-sectional studies. The objective of this longitudinal study was to determine whether living in a farm environment is associated with lower incidence of asthma among children.

METHODS

A total of 13 524 asthma-free children aged 0-11 years were drawn from the Cycle 1 (1994/1995) of the Canadian National Longitudinal Survey of Children and Youth (NLSCY). Subjects were categorized as dwelling in rural farming, rural non-farming and non-rural environments. Incidence of physician-diagnosed asthma was determined at Cycle 2 (1996/1997). Bootstrap logistic regression method was used to adjust for design effect in the NLSCY.

RESULTS

The 2-year cumulative incidence of asthma was 2.3%, 5.3% and 5.7% among children living in farming, rural non-farming and non-rural environments, respectively. From the multivariate analysis with adjustment for important confounders, children from a farming environment had a reduced risk of asthma compared with children from rural non-farming environment with odds ratios (OR) of 0.22 (95% CI: 0.07-0.74) and 0.39 (95% CI: 0.24-0.65) for children with and without parental history of asthma, respectively. Children living in a non-rural environment with parental history of asthma had an increased risk of asthma incidence when compared with children living in rural non-farming environment (OR = 2.51, 95% CI: 1.56-4.05).

CONCLUSION

This longitudinal study expands on observational study results which suggest a reduced risk of developing asthma associated with living in a farming environment.

A prospective study on the association between hay fever among children and incidence of asthma in East Germany

BACKGROUND

Aim of this study was to examine the effect of hay fever in childhood for asthma onset from childhood to adulthood in a prospective cohort of 3,199 asthma-free children, initially aged 5-13 years, which were followed for up to 12 years in East-Germany.

METHODS

Crude and adjusted incidence rate ratios (IRR) of asthma onset due to hay fever at baseline were calculated by a generalized estimation equation approach accounting for person years at risk, age at study entry, parental asthma, and gender.

RESULTS

Overall 142 incident cases of asthma were observed. Prevalence of hay fever at baseline was 4%. Crude and adjusted IRR were essentially the same and showed overall and in each age group a substantial higher risk of asthma onset due to hay fever. The adjusted IRR was 4 overall and ranged between 3 and 5 within the three age groups. Restricting the analysis to those participants, who were 17-25 years of age at the end of follow-up resulted in similar IRR.

CONCLUSION

Hay fever in childhood is a strong predictor of asthma onset later in life up to adulthood. The preventive potential of early and efficient treatment of allergic rhinitis to avoid asthma development needs to be investigated.

Meta-analyses of the associations of respiratory health effects with dampness and mold in homes

The Institute of Medicine (IOM) of the National Academy of Sciences recently completed a critical review of the scientific literature pertaining to the association of indoor dampness and mold contamination with adverse health effects. In this paper, we report the results of quantitative meta-analyses of the studies reviewed in the IOM report plus other related studies. We developed point estimates and confidence intervals (CIs) of odds ratios (ORs) that summarize the association of several respiratory and asthma-related health outcomes with the presence of dampness and mold in homes. The ORs and CIs from the original studies were transformed to the log scale and random effect models were applied to the log ORs and their variance. Models accounted for the correlation between multiple results within the studies analyzed. Central estimates of ORs for the health outcomes ranged from 1.34 to 1.75. CIs (95%) excluded unity in nine of 10 instances, and in most cases the lower bound of the CI exceeded 1.2. Based on the results of the meta-analyses, building dampness and mold are associated with approximately 30-50% increases in a variety of respiratory and asthma-related health outcomes.

PRACTICAL IMPLICATIONS

The results of these meta-analyses reinforce the IOM's recommendation that actions be taken to prevent and reduce building dampness problems, and also allow estimation of the magnitude of adverse public health impacts associated with failure to do so.

Incidence of presentation of common functional gastrointestinal disorders in children from birth to 5 years: a cohort study

BACKGROUND & AIMS

Gastroesophageal reflux disease (GERD), abdominal pain of unknown origin, and constipation are thought to be causes for frequent medical visits during childhood. The aim of this study was to estimate the incidences, repeat presentation, clinical symptoms, and sociodemographic risk factors in children who medically presented for GERD, abdominal pain of unknown origin, and constipation from birth to 5 years.

METHODS

This was a population-based, retrospective birth cohort study of all children born to mothers residing in Rochester, Minnesota who remained in the area until at least age 5 (n = 5718). The medical records of all individuals were searched for relevant diagnostic billing codes for GERD, abdominal pain of unknown origin, and constipation, without another underlying diagnosis, and manually reviewed. Parental sociodemographic factors collected from birth certificate records on patients and matched controls were compared.

RESULTS

The incidence for childhood (age, <5 y) presentation of GERD, abdominal pain of unknown origin, and constipation was .9/1000 person-years, 4.5/1000 person-years, and 6.8/1000 person-years, respectively; there were no significant differences between boys and girls. Three or more medical visits by age 5 occurred in 11%, 19%, and 24% of children who were seen for abdominal pain of unknown origin, constipation, and GERD, respectively. Single parentage, maternal age (<18 y), and maternal education (<high school) were not associated with abdominal pain or constipation presentation.

CONCLUSIONS

The incidences of presentation for GERD, abdominal pain of unknown origin, and constipation are among the highest for pediatric disorders, and a cause for repeated medical consultations.

Asthma is associated with preterm birth but not with small for gestational age status among a population-based cohort of Medicaid-enrolled children <10 years of age

BACKGROUND

Few population-based studies have evaluated the association between birth weight or gestation and subsequent clinically significant asthma.

METHODS

Birth records of 37 349 Alaska residents <10 years of age who were enrolled in Medicaid for at least 365 days during 1999-2002 were linked to a Medicaid billing file. The occurrence of asthma and lower respiratory infections during the study period was categorised on the basis of standard International Classification of Diseases 9th Revision codes. The association between gestational age or small for gestational age status and asthma outcomes was adjusted for recent history of lower respiratory infection, years of Medicaid enrolment, age at enrolment and a variety of birth-related factors.

RESULTS

Among children <5 years of age, the adjusted odds ratio (OR) for developing asthma decreased by 5.5% (95% confidence interval (CI) -0.2 to 10.9) and 7.9% (95% CI 5.2 to 10.4) per additional week of gestational age for children without and with any lower respiratory tract infection, respectively. For children > or =5 years of age, the adjusted OR for developing asthma decreased by 3.4% (95% CI -2.8 to 9.8) and 3.7% (95% CI -2.0 to 9.2) per additional week of gestation for those without and with lower respiratory tract infection, respectively. Among all children with asthma, the adjusted OR for hospitalisation due to asthma decreased by 6.9% (95% CI 2.1 to 11.5) for each additional week of gestational age. Small for gestational age status was not significantly associated with asthma outcomes.

CONCLUSIONS

Preterm birth but not small for gestational age status predicted subsequent asthma outcomes. Adverse effects of preterm birth on asthma outcomes persist beyond age 5 years.

Diverging prevalence trends of atopic disorders in Norwegian children. Results from three cross-sectional studies

BACKGROUND

During the last decades there has been extensive epidemiological research to explore the increasing prevalence of asthma and allergy in childhood. The worldwide variations in prevalence of these diseases necessitate regional rapports. Furthermore, time-trend analyses with comparable methods are important in order to monitor the rapidly changing prevalence of these diseases.

METHODS

Three cross-sectional questionnaire-based studies of asthma and allergy in schoolchildren were conducted in the counties of Troms and Finnmark, in northern Norway in 1985, 1995 and 2000. The two former studies included children from randomly selected primary schools (n = 1794/1985, n = 1432/1995). The latter study was a part of ISAAC-II Europe study (n = 3853). Identical items of asthma and allergy were employed. The analyses comprised only children 9-11 years of age.

RESULTS

The prevalence of asthma was 9.3, 13.2 and 13.8% in 1985, 1995 and 2000, respectively. However, great gender differences were detected; the prevalence of asthma increased in males from 1995 to 2000, from 14.1 to 17.0%, RR = 1.2 (95% CI 1.0-1.5), but decreased in females 1995 to 2000, from 12.3 to 10.5%, RR = 0.9 (95% CI 0.7-1.1). Furthermore, in children with asthma, a changing trend was found in the external factors that perceived symptoms, from typical allergens towards other, unspecific agents. The prevalence of self-reported atopic eczema/dermatitis syndrome (AEDS) was 13.4, 21.1 and 20.8% in 1985, 1995 and 2000, respectively. The prevalence of self-reported allergic rhinoconjunctivitis was in 16.5, 24.7 and 29.6% 1985, 1995 and 2000, respectively, RR (2000/1995) = 1.2 (95% CI 1.1-1.3).

CONCLUSION

The prevalence of asthma in girls has reached a plateau and even decreased from 1995 to 2000 which is in contrast to the asthma prevalence in boys that tends to continuously increase. The prevalence of AEDS which increased substantially between 1985 and 1995 did not change from 1995 to 2000. However, the prevalence of allergic rhinoconjunctivitis increased steadily from 1985, 1995 to 2000.

Swedish patients' perceptions of a preoperative skin test

PREOPERATIVE PREPARATION is an important aspect of creating a safe and pleasant hospital experience for surgical patients. Evaluating patient satisfaction, however, also depends on determining patients' perceptions of the care they receive. THIS STUDY used a descriptive, qualitative method with a phenomenographic approach to determine how patients perceived undergoing a preoperative skin test that was developed to ascertain what substances might result in intraoperative reactions in patients with allergies, asthma, or eczema. OVERALL, the patients had positive perceptions of the skin test; however, the results indicate a need for improved and individualized preoperative instruction that focuses on patients from a holistic perspective.

Agreement between parental and self-completed questionnaires about asthma in teenagers

In studies of asthma in children, a common method is for the parents to complete questionnaires about their child's asthma symptoms. With longitudinal studies of asthma, children reach an age when they can complete the questionnaire themselves. The aim of this paper was to compare the prevalence of asthma symptoms as well as the agreement between responses to an asthma questionnaire completed by teenagers and their parents. As a part of the Obstructive Lung Disease in Northern Sweden Study (OLIN) pediatric study, where 3345, 13-14-yr-old children completed an asthma questionnaire, 294 (84%) randomly selected parents also completed the questionnaire, which included the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. There were no significant differences in the prevalence of wheeze in the last 12 months, ever asthma, or physician diagnosed asthma as reported by the parents compared with the teenagers. However, the teenagers reported a significantly higher prevalence of wheeze during or after exercise. The absolute agreement was generally very high while the level of agreement (kappa-value) was slightly lower. The highest results in both absolute agreement and kappa-value, were reached by the questions on diagnosis of asthma (98.9% and 0.93), use of asthma medicines (95.5% and 0.78), and whether the child ever had had asthma (97.2% and 0.86), respectively. In conclusion, the agreement between the parents' and the teenagers' responses to the asthma questionnaire was good. The change in methodology from parental to self-completion of the questionnaire did not affect the results in the study.

The size of the problem of managing asthma

Asthma is now the commonest chronic disease in industrialised countries and its prevalence is rising throughout the world. However, despite the availability of very effective treatments many patients with asthma have poorly controlled symptoms and frequent exacerbations, some of which require hospital admission. Important factors contributing to poor asthma control are failure to recognise asthma as a diagnosis, non-implementation of asthma management guidelines and patient non-compliance with therapy. The guidelines themselves have many inherent limitations. Chief among these is that the evidence upon which they are based may be misleading. The evidence used to support recommendations in guidelines is derived from double-blind, placebo-controlled studies in very carefully selected patients who are usually compliant with therapy and instructed in the use of inhalers. In the 'real world' things are very different and patients frequently fail to understand how to use their therapy and are often non-compliant. Reasons for non-compliance are complex and include complicated drug and dosing regimens and inability to use inhaler devices correctly; particularly pressurised metered dose inhalers (pMDIs) due to difficulty co-ordinating device activation and inhalation. Dry powder inhalers (DPIs) preclude the need to co-ordinate inspiration with activation, are easy and convenient to use and are environmentally friendly. There is no doubt that the type of inhaler is just as important as the class of drug in the long-term management of asthma. Improvements in inhaled drug delivery will continue to be important in improving asthma management.

Sex differences among children 2-13 years of age presenting at the emergency department with acute asthma

Hospitalization rates for asthma have been reported to be higher in males than females in children under age 15, but it is not clear whether this disparity reflects gender differences in prevalence, severity, or treatment. We performed a prospective cohort study as part of the Emergency Medicine Network. Patients aged 2-13 years who presented to the emergency department (ED) with acute asthma underwent a structured interview in the ED and another by telephone 2 weeks later. Of 1,602 patients, 61% (95% CI, 59-64%) were boys. Girls were slightly older than boys, although no material differences existed in acute presentation, chronic asthma characteristics, ED treatment, or ED course. There was no difference in admission rates for boys or girls (20% vs. 22%; P = 0.48). This finding persisted when adjusting for other factors in a multivariate logistic regression model. No sex differences were observed for relapse or ongoing exacerbation on univariate or multivariate analysis. These data suggest that asthma is not inherently more severe in boys with asthma compared to girls, and that the increased rate of hospitalizations in boys under age 13 is due to differences in prevalence, not severity.

Early-life environmental risk factors for asthma: findings from the Children's Health Study

Early-life experiences and environmental exposures have been associated with childhood asthma. To investigate further whether the timing of such experiences and exposures is associated with the occurrence of asthma by 5 years of age, we conducted a prevalence case-control study nested within the Children's Health Study, a population-based study of > 4,000 school-aged children in 12 southern California communities. Cases were defined as physician-diagnosed asthma by age 5, and controls were asthma-free at study entry, frequency-matched on age, sex, and community of residence and countermatched on in utero exposure to maternal smoking. Telephone interviews were conducted with mothers to collect additional exposure and asthma histories. Conditional logistic regression models were fitted to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Asthma diagnosis before 5 years of age was associated with exposures in the first year of life to wood or oil smoke, soot, or exhaust (OR = 1.74; 95% CI, 1.02-2.96), cockroaches (OR = 2.03; 95% CI, 1.03-4.02), herbicides (OR = 4.58; 95% CI, 1.36-15.43), pesticides (OR = 2.39; 95% CI, 1.17-4.89), and farm crops, farm dust, or farm animals (OR = 1.88; 95% CI, 1.07-3.28). The ORs for herbicide, pesticide, farm animal, and crops were largest among children with early-onset persistent asthma. The risk of asthma decreased with an increasing number of siblings (ptrend = 0.01). Day care attendance within the first 4 months of life was positively associated with early-onset transient wheezing (OR = 2.42; 95% CI, 1.28-4.59). In conclusion, environmental exposures during the first year of life are associated with childhood asthma risk.