Synthetic bedding and wheeze in childhood

Poultry exposure and environmental protection against asthma in rural children

BACKGROUND

Asthma is one of the most common chronic diseases in childhood, and the prevalence has been increasing over the past few decades. One of the most consistent epidemiological findings is that children living in a farming or rural environment are protected from development of asthma and allergies, but the protective factors in rural China are not clear.

METHODS

A community-based, cross-sectional epidemiological study was performed in a total of 17,587 children aged 5-8 years, 3435 from Hong Kong (urban) and 14,152 from Conghua (rural county in southern China). Asthma and allergic symptoms as well as environmental exposures were ascertained by using a standardized and validated questionnaire.

RESULTS

The prevalence of current wheeze was significantly lower in rural Conghua than that of urban Hong Kong (1.7% vs. 7.7%, p < 0.001). A lower rate of asthma ever was also reported in rural children compared with their urban counterparts (2.5% vs. 5.3%, p < 0.001). After adjusting for confounding factors, exposure to agricultural farming (adjusted odds ratio 0.74, 95% confidence interval: 0.56-0.97) and poultry (0.75, 0.59-0.96) were the most important factors associated with the asthma-protective effect in the rural area. Further propensity score-adjusted analysis indicated that such protection conferred by living in the rural environment was mainly attributable to poultry exposure.

CONCLUSIONS

We confirmed that the prevalence of asthma and atopic disorders was significantly lower in rural children when compared with their urban peers. Exposure to poultry and agricultural farming are the most important factors associated with asthma protection in the rural area.

Pollution and respiratory disease: can diet or supplements help? A review

Pollution is known to cause and exacerbate a number of chronic respiratory diseases. The World Health Organisation has placed air pollution as the world's largest environmental health risk factor. There has been recent publicity about the role for diet and anti-oxidants in mitigating the effects of pollution, and this review assesses the evidence for alterations in diet, including vitamin supplementation in abrogating the effects of pollution on asthma and other chronic respiratory diseases. We found evidence to suggest that carotenoids, vitamin D and vitamin E help protect against pollution damage which can trigger asthma, COPD and lung cancer initiation. Vitamin C, curcumin, choline and omega-3 fatty acids may also play a role. The Mediterranean diet appears to be of benefit in patients with airways disease and there appears to be a beneficial effect in smokers however there is no direct evidence regarding protecting against air pollution. More studies investigating the effects of nutrition on rapidly rising air pollution are urgently required. However it is very difficult to design such studies due to the confounding factors of diet, obesity, co-morbid illness, medication and environmental exposure.

Occupational phthalate exposure and health outcomes among hairdressing apprentices

We studied occupational exposure to phthalates from first-morning-void urine sample of hairdressing apprentices by HPLC-MS/MS analyses and association with health status. Metabolites of mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono ethyl phthalate (MEP), mono- n-butyl phthalate (MnBP) and mono-iso-butyl phthalate (MiBP) were detected in all urine samples, followed by metabolites mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono(2-etylhexyl) phthalate (MEHP) occurring in 97.06% and 86.76% of samples, respectively. Positive associations for females were observed between MnBP and fat-free mass index (FFMI) and age; negative associations were found between MEHP, MEOHP, MEHHP, sum of MEHP, MEHHP, MEOHP and vital capacity and also between MEHP and forced vital capacity (FVC of predicted value (PV)). Lengths of exposure were associated to MnBP, MEHHP, and MEP. We also documented positive associations between anthropometry (body mass index, waist-to-height ratio (WHtR), FFMI, fat mass index) and pulmonary function FVC% of PV for females and negative associations between WHtR, waist-to-hip ratio, FFMI and ratio of forced expiratory volume in 1 s (FEV₁) to FVC (FEV₁/FVC). We assume that factors of occupational environment of hairdressing apprentices are affected by phthalates and resulted in negative outcomes in breathing mechanism and influence of body composition. Adipose tissue could play role as confounding factor in urine excretion of phthalates because of their lipid solubility and accumulation.

Early risk factors for pubertal asthma

BACKGROUND

Early life risk factors are previously described for childhood asthma, but less is known related to asthma in adolescence. We aimed to investigate early risk factors (before 2 years) for pubertal asthma and secondarily for pubertal asthma phenotypes based upon allergic comorbidities.

METHODS

Based on data from 550 adolescents in the prospective birth cohort 'Environment and Childhood Asthma' study, subjects were categorized by recurrent bronchial obstruction (rBO) 0-2 years, asthma 2-10 years, and pubertal asthma from 10 to 16 years including incident asthma in puberty and asthma in remission from 10 to 16 years or as never rBO/asthma 0-16 years. Asthma in puberty was further classified based on the comorbidities atopic dermatitis and allergic rhinitis (AR) from 10 to 16 years. Twenty-three common asthma risk factors identified by 2 years of age, including frequency and persistence of bronchial obstruction (severity score), were analysed by weighted logistic regression for each phenotype.

RESULTS

In adjusted models, the risk of pubertal asthma increased significantly with higher severity score, parental rhinitis, being the firstborn child, and familial stress around birth. Pubertal asthma in remission was significantly associated with severity score and number of lower respiratory tract infections and inversely associated with breastfeeding beyond 4 months. Pubertal incident asthma was more common among firstborn children. All asthma phenotypes with allergic diseases were significantly associated with severity score, whereas familial perinatal stress increased the risk of asthma only. Asthma combined with AR was associated with parental asthma and being firstborn, whereas the risk of asthma with both atopic dermatitis and AR increased with higher paternal education, atopic dermatitis, being firstborn, and familial perinatal stress.

CONCLUSION AND CLINICAL RELEVANCE

Important early risk factors for pubertal asthma were early airways obstruction, parental rhinitis, being the firstborn child, and perinatal familial stress.

Childhood asthma-predictive phenotype

Wheezing is a fairly common symptom in early childhood, but only some of these toddlers will experience continued wheezing symptoms in later childhood. The definition of the asthma-predictive phenotype is in children with frequent, recurrent wheezing in early life who have risk factors associated with the continuation of asthma symptoms in later life. Several asthma-predictive phenotypes were developed retrospectively based on large, longitudinal cohort studies; however, it can be difficult to differentiate these phenotypes clinically as the expression of symptoms, and risk factors can change with time. Genetic, environmental, developmental, and host factors and their interactions may contribute to the development, severity, and persistence of the asthma phenotype over time. Key characteristics that distinguish the childhood asthma-predictive phenotype include the following: male sex; a history of wheezing, with lower respiratory tract infections; history of parental asthma; history of atopic dermatitis; eosinophilia; early sensitization to food or aeroallergens; or lower lung function in early life.

Phthalate exposure and health-related outcomes in specific types of work environment

Many toxic substances in the workplace can modify human health and quality of life and there is still insufficient data on respiratory outcomes in adults exposed to phthalates. The aim of this work was to assess in waste management workers from the Nitra region of Slovakia (n = 30) the extent of exposure to phthalates and health-related outcomes. Four urinary phthalate metabolites mono(2-ethylhexyl) phthalate (MEHP), monobutyl phthalate (MnBP), monoethyl phthalate (MEP) and monoisononyl phthalate (MiNP) were determined by high-performance liquid chromatography with mass spectrometry (HPLC-MS/MS). Urinary concentration of MEHP was positively associated with ratio of forced expiratory volume in 1 s to forced vital capacity % (FEV₁/FVC) (r = 0.431; p = 0.018) and MiNP with fat free mass index (FFMI) (r = 0.439; p = 0.015). The strongest predictor of pulmonary function was the pack/year index as smoking history that predicted a decrease of pulmonary parameters, the FEV₁/FVC, % of predicted values of peak expiratory flow (PEF % of PV) and FEV₁ % of PV. Unexpectedly, urinary MEHP and MINP were positively associated with pulmonary function expressed as PEF % of PV and FEV₁/FVC. We hypothesize that occupational exposure to phthalates estimated from urinary metabolites (MEHP, MiNP) can modify pulmonary function on top of lifestyle factors.

Phthalate exposure and allergy in the U.S. population: results from NHANES 2005-2006

BACKGROUND

Environmental exposures to phthalates, particularly high-molecular-weight (HMW) phthalates, are suspected to contribute to allergy.

OBJECTIVE

We assessed whether phthalate metabolites are associated with allergic symptoms and sensitization in a large nationally representative sample.

METHODS

We used data on urinary phthalate metabolites and allergic symptoms (hay fever, rhinitis, allergy, wheeze, asthma) and sensitization from participants ≥ 6 years of age in the National Health and Nutrition Examination Survey (NHANES) 2005-2006. Allergen sensitization was defined as a positive response to at least one of 19 specific IgE antigens (≥ 0.35 kU/L). Odds ratios (ORs) per one log10 unit change in phthalate concentration were estimated using logistic regression adjusting for age, race, body mass index, gender, creatinine, and cotinine. Separate analyses were conducted for children (6-17 years of age) and adults.

RESULTS

The HMW phthalate metabolite monobenzyl phthalate (MBzP) was the only metabolite positively associated with current allergic symptoms in adults (wheeze, asthma, hay fever, and rhinitis). Mono-(3-carboxypropyl) phthalate and the sum of diethylhexyl phthalate metabolites (both representing HMW phthalate exposures) were positively associated with allergic sensitization in adults. Conversely, in children, HMW phthalate metabolites were inversely associated with asthma and hay fever. Of the low-molecular-weight phthalate metabolites, monoethyl phthalate was inversely associated with allergic sensitization in adults (OR = 0.79; 95% CI: 0.70, 0.90).

CONCLUSION

In this cross-sectional analysis of a nationally representative sample, HMW phthalate metabolites, particularly MBzP, were positively associated with allergic symptoms and sensitization in adults, but there was no strong evidence for associations between phthalates and allergy in children 6-17 years of age.

Influence of genetic polymorphisms on the association between phthalate exposure and pulmonary function in the elderly

BACKGROUND

Phthalates are prevalent environmental exposure chemicals with rising concern on various health effects, including pulmonary function. Meanwhile, elderly people are more susceptible to environmental exposure, and their decreasing lung function is an important health issue.

OBJECTIVES

To investigate the association between urinary phthalate metabolite levels and indices for pulmonary function, and evaluate effect modification by genetic polymorphisms of oxidative-stress related genes, catalase (CAT), superoxide dismutase (SOD2), and myeloperoxidase (MPO) in elderly Koreans.

METHODS

We conducted a panel study on 418 individuals over 60 years old in Seoul, Korea, and repeatedly measured urinary phthalate metabolite levels and ran pulmonary function tests. Genetic polymorphisms of CAT (rs769218, rs769217), SOD2 (rs4880, rs2758331, rs5746136) and MPO (rs2071409, rs7208693) were determined. Mixed effect model was used to investigate association of phthalate levels with pulmonary function indices and to examine the effect of CAT, SOD2 and MPO polymorphisms on the association.

RESULTS

Inverse association was demonstrated between sum of mono-(2-ethyl-5-hydroxyhexyl) phthalate and mono-(2-ethyl-5-oxohexyl) phthalate (∑DEHP) levels and FEV1/FVC (β=-0.632, p=0.0275) or FEF25-75 (β=-0.077, p=0.025) after adjusting for age, months after previous measurements, sex, body mass index, cotinine, mean temperature and dew point. The effect of ∑DEHP on lung function was significant only in subjects with certain genotypes, and having all significant genotypes in three genes showed significant difference in the phthalate-pulmonary function association (FEV1/FVC: β=-2.169, p=0.0032; FEF25-75: β=-0.155, p=0.0103), while other combinations showed less estimate size without any significance.

CONCLUSIONS

Urinary phthalate metabolites levels are associated with decreasing pulmonary function in elderly Koreans, and effect modification of certain CAT, SOD2 and MPO polymorphisms on the association is suggested.

The origins of health and disease: the influence of maternal diseases and lifestyle during gestation

According to the Barker hypothesis, the period of pregnancy and the intrauterine environment are crucial to the tendency to develop diseases like hypertension, diabetes, coronary heart disease, metabolic disorders, pulmonary, renal and mental illnesses. The external environment affects the development of a particular phenotype suitable for an environment with characteristics that closely resemble intrauterine conditions. If the extra-uterine environment differs greatly from the intra-uterine one, the fetus is more prone to develop disease. Subsequent studies have shown that maternal diseases like depression and anxiety, epilepsy, asthma, anemia and metabolic disorders, like diabetes, are able to determine alterations in growth and fetal development. Similarly, the maternal lifestyle, particularly diet, exercise and smoking during pregnancy, have an important role in determining the risk to develop diseases that manifest themselves both during childhood and particularly in adulthood. Finally, there are abundant potential sources of pollutants, both indoor and outdoor, in the environment in which the child lives, which can contribute to an increased probability to the development of several diseases and that in some cases could be easily avoided.

Feather bedding and childhood asthma associated with house dust mite sensitisation: a randomised controlled trial

INTRODUCTION

Observational studies report inverse associations between the use of feather upper bedding (pillow and/or quilt) and asthma symptoms but there is no randomised controlled trial (RCT) evidence assessing the role of feather upper bedding as a secondary prevention measure.

OBJECTIVE

To determine whether, among children not using feather upper bedding, a new feather pillow and feather quilt reduces asthma severity among house dust mite (HDM) sensitised children with asthma over a 1-year period compared with standard dust mite avoidance advice, and giving children a new mite-occlusive mattress cover.

DESIGN

RCT.

SETTING

The Calvary Hospital in the Australian Capital Territory and the Children's Hospital at Westmead, Sydney, New South Wales.

PATIENTS

197 children with HDM sensitisation and moderate to severe asthma. Intervention New upper bedding duck feather pillow and quilt and a mite-occlusive mattress cover (feather) versus standard care and a mite-occlusive mattress cover (standard).

MAIN OUTCOME MEASURES

The proportion of children reporting four or more episodes of wheeze in the past year; an episode of speech-limiting wheeze; or one or more episodes of sleep disturbance caused by wheezing; and spirometry with challenge testing. Statistical analysis included multiple logistic and linear regression.

RESULTS

No differences between groups were found for primary end points--frequent wheeze (OR 1.51, 95% CI 0.83 to 2.76, p=0.17), speech-limiting wheeze (OR 0.70, 95% CI 0.32 to 1.48, p=0.35), sleep disturbed because of wheezing (OR 1.17, 95% CI 0.64 to 2.13, p=0.61) or for any secondary end points. Secondary analyses indicated the intervention reduced the risk of sleep being disturbed because of wheezing and severe wheeze to a greater extent for children who slept supine.

CONCLUSION

No differences in respiratory symptoms or lung function were observed 1 year after children with moderate-severe asthma and HDM sensitisation were given a mite-occlusive mattress cover and then received either feather upper bedding (pillow and quilt) or standard bedding care.

Prevalence and factors linked to allergic rhinitis in 10 and 11-year-old children in Almería. Isaac Phase II, Spain

BACKGROUND

Allergic rhinitis affects 10-30% of children in developed countries and has increased in frequency over the last few decades, probably due to changes in the environment and life style.

AIM

To assess the prevalence, severity, and factors linked to rhinitis in 10 and 11-year-old children from Almeria (Spain).

METHODS

As part of ISAAC II, a cross-sectional survey was conducted among a representative sample of 1143 schoolchildren in spring and autumn of 2001, using homologated questionnaires and skin-prick testing.

RESULTS

The overall prevalence of rhinitis and rhinoconjunctivitis were 38.9% and 24.8%, respectively, 17.9% had medically diagnosed rhinitis. During the previous year symptoms disturbed daily activities and school attendance in some measure in 40% and 26% of children with rhinitis, respectively. The risk factors found in the multiple logistic regression analysis were atopy (OR 2.57; 95% CI 1.92-3.42); cat contact at home during first year of life (OR 2.4 95% CI 1.13-5.12); prior medical diagnosis of asthma (OR 2.2; 95% CI 1.22-4.02); nocturnal cough in absence of colds (OR 1.9; 95% CI 1.25-2.97); diagnosis of rhinitis in one of the parents (OR 1.8; 95% CI 1.31-2.59); wheezing at any time (OR 1.6; 95% CI 1.18-2.28); and nursery school attendance (OR 1.5; 95% CI 1.21-2.5).

CONCLUSIONS

The prevalence of rhinitis found is superior to that of other centres participating in the ISAAC Phases I and II, and coexists with asthma and eczema in many children. The independent risk factors associated to rhinitis are in accordance with previous reports.

[Potential risk of indoor semivolatile organic compounds indoors to human health]

The concerns on indoor contamination by semivolatile organic compounds (SVOCs) are increasing. Because of the high boiling points in the range of 260-380 degrees C, SVOCs are considered to vaporize poorly under living conditions. However, a wide variety of SVOCs were detected in indoor air and house dust in previous studies. Indeed, we found SVOCs frequently in both air and dusts of residential dwellings in Sapporo city in 2006. Among SVOCs, there are a number of findings indicating that phthalates and pesticides use associated with allergy or bronchial obstruction. The adjuvant effect of phthalates, particularly monoesters, was shown in animal experiments and the association between allergy prevalence and exposure to phthalates or indoor materials containing plasticizers was observed in previous epidemiological studies. Regarding pesticides involving organophosphates and pyrethroids among others, the association of pesticide use with asthma or chronic bronchitis was observed in commercial pesticide applicators or farmers. Because SVOCs were often found in air and house dust of residential dwellings, the risk of SVOC exposure should be assessed in the Japanese general population.

Early identification of atopy in the prediction of persistent asthma in children

The long-term solution to the asthma epidemic is thought to be prevention, and not treatment of established disease. Atopic asthma arises from gene-environment interactions, which mainly take place during a short period in prenatal and postnatal development. These interactions are not completely understood, and hence primary prevention remains an elusive goal. We argue that primary-care physicians, paediatricians, and specialists lack knowledge of the role of atopy in early life in the development of persistent asthma in children. In this review, we discuss how early identification of children at high risk is feasible on the basis of available technology and important for potential benefits to the children. Identification of an asthmatic child's atopic status in early life has practical clinical and prognostic implications, and sets the basis for future preventative strategies.

Environmental factors and allergic disorders

Despite numerous studies on possible associations between environmental exposure and allergic disorders, any conclusions made remain a matter of controversy. We conducted a review of evidence in relation to environmental and nutritional determinants and wheeze, asthma, atopic dermatitis, and allergic rhinitis. Identified were 263 articles for analysis after consideration of 1093 papers that were published since 2000 and selected by electronic search of the PubMed database using keywords relevant to epidemiological studies. Most were cross-sectional and case-control studies. Several prospective cohort studies revealed inconsistent associations between various environmental factors and the risk of any allergic disorder. Therefore, the evidence was inadequate to infer the presence or absence of a causal relationship between various environmental exposures and allergic diseases. However, evidence is suggestive of positive associations of allergies with heredity. Because almost all the studies were performed in Western countries, the application of these findings to people in other countries, including Japan, may not be appropriate. Further epidemiological information gained from population-based prospective cohort studies, in particular among Japanese together with other Asians, is needed to assess causal relationships between various environmental factors and allergic diseases.

Symptoms of asthma and atopic disorders in preschool children: prevalence and risk factors

BACKGROUND

Published epidemiological data suggested that asthma and allergies may be increasing in preschool children. Identification of the risk factors is important for planning possible early intervention to prevent asthma. This study was designed to measure the prevalence of, and risk factors for, asthma and atopic disorders in preschool children from Hong Kong.

METHODS

Children aged 2-6 years living in Hong Kong were recruited through the local nurseries and kindergartens for this study to ascertain the presence of symptoms of asthma and various possible risk factors. The parental questionnaire was developed based on the International Study of Asthma and Allergies in Childhood questionnaire.

RESULTS

A total of 3089 children (1506 boys) from 14 nurseries and kindergartens participated in this study. The prevalence of wheeze ever and current wheeze were 16.7% and 9.3%. Two hundred and thirty-four subjects were born in mainland China and migrated to Hong Kong subsequently. When compared with children born and raised in Hong Kong, children born in mainland China had significantly lower prevalence of current wheeze (3.4% vs. 9.6%, P<0.01). Two environmental factors in the first year of life were associated with wheezing attacks within the last 12 months. They were the use of foam pillow (Odds ratio: 1.45; 95% Confidence interval: 1.04-2.00) and the use of gas as cooking fuel (1.68; 1.03-2.75). Frequent use of paracetamol was also associated with wheezing attack in the past 12 months.

CONCLUSIONS

This study confirms the high prevalence of symptoms of atopic disorders in preschool children from Hong Kong. Early environmental exposure factors are important determinants of subsequent development of asthma symptoms in the preschool years. Further studies are needed to evaluate the possible pathogenetic role of the identified risk factors.

Indoor residential chemical emissions as risk factors for respiratory and allergic effects in children: a review

Most research into effects of residential exposures on respiratory health has focused on allergens, moisture/mold, endotoxin, or combustion products. A growing body of research from outside the US; however, has associated chemical emissions from common indoor materials with risk of asthma, allergies, and pulmonary infections. This review summarizes 21 studies in the epidemiologic literature on associations between indoor residential chemical emissions, or emission-related materials or activities, and respiratory health or allergy in infants or children. Associations, some strong, were reported between many risk factors and respiratory or allergic effects. Risk factors identified most frequently included formaldehyde or particleboard, phthalates or plastic materials, and recent painting. Findings for other risk factors, such as aromatic and aliphatic chemical compounds, were limited but suggestive. Elevated risks were also reported for renovation and cleaning activities, new furniture, and carpets or textile wallpaper. Reviewed studies were entirely observational, limited in size, and variable in quality, and specific risk factors identified may only be indicators for correlated, truly causal exposures. Nevertheless, overall evidence suggests a new class of residential risk factors for adverse respiratory effects, ubiquitous in modern residences, and distinct from those currently recognized. It is important to confirm and quantify any risks, to motivate and guide necessary preventive actions.

PRACTICAL IMPLICATIONS

Composite wood materials that emit formaldehyde, flexible plastics that emit plasticizers, and new paint have all been associated with increased risks of respiratory and allergic health effects in children. Although causal links have not been documented, and other correlated indoor-related exposures may ultimately be implicated, these findings nevertheless point to a new class of little recognized indoor risk factors for allergic and respiratory disease, distinct from the current set of indoor risk factors. The available evidence thus raises initial questions about many common residential practices: for instance, using pressed wood furnishings in children's bedrooms, repainting infant nurseries, and encasing mattresses and pillows with vinyl for asthmatic children. The findings summarized here suggest a need for substantially increased research to replicate these findings, identify causal factors, and validate preventive strategies.

Infant sleeping environment and asthma at 7 years: a prospective cohort study

OBJECTIVES

We investigated the role of infant bedding items, as part of a composite bedding environment, in the development of childhood wheezing.

METHODS

This prospective cohort investigation involved 863 children who participated in an infant survey in 1988 and an asthma study in Tasmania, Australia, in 1995. The derived 3 composite infant bedding categories corresponded to increasing numbers of house dust mite (HDM)-rich bedding items used. Outcomes measured included recent and frequent wheezing.

RESULTS

Composite infant bedding used was associated with recent wheezing. Effects increased at increasing levels of HDM-rich bedding items used. Effects were further enhanced by home environmental factors of bedroom heating, recent bedroom painting, and absence of bedroom carpeting. When any 2 or more of these environmental factors were present, a strong dose-response relationship was evident.

CONCLUSIONS

Our results show that bedding exposures in infancy are prospectively associated with childhood wheezing and that home environmental conditions may modify this association.

A prospective association between cocoon use in infancy and childhood asthma

There is increasing evidence for a role for bedding items in the development of asthma. The use of some forms of synthetic bedding, such as foam mattresses and pillows, is associated with a significantly increased risk of childhood wheeze. Our aim was to examine prospectively whether the use of synthetic cocoon/baby nests in infancy is associated with the subsequent development of wheeze in childhood. Data collected in 1988 as part of the Tasmanian Infant Health Survey were linked to the cross-sectional Childhood Asthma Survey conducted in 1995 in Tasmania, Australia. We were able to match 863 records out of the 1111 in the 1988 survey. Information including parental, child-care, and the infant's sleeping environment was collected at home interview in 1988 when the infant was 1 month of age. Data including sleep environment and asthma symptoms were available for each child at age 7 years. A generalised linear model was used to calculate the adjusted relative risk (RR) estimates for symptoms of wheeze and infant cocoon use. For children who were placed in a cocoon in infancy, there was an increased risk of recent wheeze (adjusted RR = 4.33 [95% CI 2.08, 9.02]) and night wheeze (adjusted RR = 3.35 [95% CI 1.52, 7.39]) at age 7 years. In view of the increasing prevalence of childhood asthma, the identification of potentially modifiable environmental factors which might operate in infancy is of importance. The present findings implicate infant bedding choice as a significant factor and further studies on the infant sleeping environment are indicated.

The bedding environment, sleep position, and frequent wheeze in childhood

OBJECTIVE

Synthetic quilt use has been associated with increased childhood wheeze in previous studies. Our aim was to examine whether the adverse effect of synthetic quilt use on frequent wheeze differed by usual sleep position.

DESIGN, SETTING, AND PARTICIPANTS

A population-based cross-sectional study of 6378 (92% of those eligible) 7-year-olds in Tasmania, Australia, was conducted in 1995. Exercise-challenge lung function was obtained on a subset of 414 children from randomly selected schools.

EXPOSURE MEASURES

Child bedding including pillow and overbedding composition and usual sleep position by parental questionnaire.

OUTCOME MEASURES

Frequent wheeze (>12 wheeze episodes over the past year), using the International Study of Asthma and Allergies in Childhood parental questionnaire, and baseline and postexercise forced expiratory volume in 1 second lung-function measures.

RESULTS

Frequent wheeze (n = 117) was positively associated with synthetic quilts, synthetic pillows, electric blankets, and sleeping in a bottom bunk bed but did not vary by sleep position. In a nested case-control analysis, the association between synthetic quilt use and frequent wheeze differed by sleep position. Among children who slept supine, synthetic (versus feather) quilt use was associated with frequent wheeze (adjusted odds ratio: 2.37 [1.08, 5.23]). However, among nonsupine sleepers, overlying synthetic quilt use was not associated with frequent wheeze (adjusted odds ratio: 1.06 [0.60, 1.88]). This difference in quilt effect by sleep position was highly significant. Similarly, synthetic quilt use was associated with lower postexercise forced expiratory volume in 1 second measures among supine but not nonsupine sleeping children.

CONCLUSION

An increasing focus on the bedding environment immediately adjacent to the nose and mouth is required for respiratory disorders provoked by bedding, such as child asthma characterized by frequent wheeze.

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.