Indoor environmental risk factors in young asthmatics: a case-control study

One hundred and ninety three children with asthma and 318 controls aged 1-4 years were evaluated for atopic heredity and exposure to possible indoor risk factors for asthma-for example exposure to furred pets, tobacco smoke, and home dampness. A subgroup of cases were classified as cat and/or dog allergic on the basis of skin prick tests. Heredity for asthma was a significant risk factor (odds ratio (OR) 3.0, confidence interval (CI) 2.1 to 4.6). Environmental tobacco smoke was associated with an excess risk for asthma (OR 1.7, CI 1.1 to 2.3) and signs of home dampness tended to increase this risk (OR 1.3, CI 0.9 to 2.0). High dose exposure to cat and/or dog resulted in an increased risk only in asthma cases sensitised to cat and/or dog (OR 2.7, CI 1.0 to 7.3). A combination of high dose exposure to cat and/or dog, environmental tobacco smoke and damp housing was associated with an OR of 8.0 (CI 1.9 to 34.1). Raised indoor humidity has been shown to reflect low air exchange, which may also lead to increased doses of inhaled aeroallergens and tobacco smoke, and contribute to the interaction between the three risk factors.     

Associations between home dampness and presence of molds with asthma and allergic symptoms among young children in the tropics

Existing literature has shown that home dampness increases indoor mold burden and is associated with increased allergic symptoms among young children in temperate environments. There is no report of any studies of similar nature in the tropics where conditions are characterized typically by high temperatures and humidity with rainfall throughout the year. To evaluate if there are associations between the prevalence of current asthma and allergic symptoms in young children (age 1.5-6 yr) with dampness and indoor mold in children's bedrooms in a tropical environment. A cross-sectional study adopting an expanded and modified ISAAC--International Study on Asthma and Allergies in Children--questionnaire for the evaluation of asthma and allergies was conducted on 6794 children (4759 responded--70%) attending 120 randomly selected daycare centers. Specific information on demographics, home dampness, and the visible presence of indoor molds were obtained. The prevalence ratios (PR) and 95% confidence interval (CI) were determined by Cox proportional hazard regression model with assumption of a constant risk period as recommended for cross-sectional studies. The calculated PRs were controlled for age, gender, ethnicity, socio-economic status, type of housing, maternal and paternal atopy, respiratory infections, environmental tobacco smoke (ETS) exposure, and food allergy. After adjusting for potential confounding effects, home dampness was observed to be significantly associated with current symptoms of rhinoconjunctivitis (adjusted PR 1.53, 95% CI: 1.00-2.33). The visible presence of mold was significantly associated with current symptoms of rhinitis (PR 1.55, 95% CI: 1.16-2.07) and rhinoconjunctivitis (PR 2.38, 95% CI: 1.51-3.75). Indoor dampness and mold in children's bedroom are important risk factors associated with allergic symptoms in young children in Singapore.     

Risk factors in early childhood for sensitization to airborne allergens

To examine the association between environmental exposure during the first two years of life and development of atopic disease later in child-hood, 115 children sensitized to airborne allergens and 54 non allergic controls were investigated. Fifty-seven of the atopic children were skin prick test (SPT) positive to house dust mites (HDM). Information on exposure was obtained from questionnaires. Parental allergy was a more important risk factor for development of atopy than any of the environmental risk factors. Exposure during the 2 first yr of life to environmental tobacco smoke (ETS) and home dampness was more frequently found among the HDM-sensitized children than among the controls (OR = 2. 8, CI 1. 0-7. 3 and OR = 4. 6, CI 1. 4-15. 0 respectively). A combination of these two factors seemed to be particularly harmful (OR = 8. 7, CI 2. 3-33. 1). Similar but less pronounced effects were seen for children with other allergies. Later in life exposure both to dampness and ETS was of the same magnitude in the atopic children as in the controls. It appears that exposure to environmental factors during the first few years of life may trigger for development of atopic disease and that interactions may be of particular importance.     

Urban living as a risk factor for atopic sensitization in Swedish schoolchildren

The prevalence of atopic sensitization was compared among all pupils in three urban school classes (median age 10, 12 and 14 years, respectively) and three corresponding classes in the adjacent rural district (642 pupils in all). A written questionnaire, oral interview and skin prick testing against 7 allergens were used, with skin tests performed on 93.4 % of the urban, and 92.0 % of the rural pupils. Contact with domestic animals was much more common in the rural area. Urban living was a risk factor for at least one positive skin test to pollen or animal dander, with odds ratio (OR) 1.83 and confidence interval (CI) 1.26–2.67. This was even more pronounced for children with both positive skin test and allergic symptoms (OR 2.13; CI 1.38–3.28). An increased prevalence of positive skin prick tests in the urban area compared with the rural environment was also found for 3 individual allergens, i.e. birch pollen (OR 1.78), timothy pollen (OR 1.87) and cat dander (OR 2.29). The relative risk for positive skin test in the urban area was further increased when standardized for allergic heredity, type of dwelling, daily exposure to tobacco smoke and dampness or abnormal smell in the home. This study suggests that various adjuvant factors increase the risk of sensitization in urban environments, particularly among children with a positive family history of allergy     

Early exposure and sensitization to cat and dog: Different effects on asthma risk after wheezing in infancy

Birth cohort studies have suggested that early exposure to furred pets protects from later asthma and allergy. The aim of the present study was to evaluate the association between exposure or sensitization to cat or dog in infancy, and later asthma and allergy assessed at the median ages of 4.0, 7.2 and 12.3 yr, in children who have wheezed at <24 months of age. Exposure to cat and dog in infancy was assessed by interviewing the parents. The child was considered as sensitized, if the allergen-specific IgE to cat or to dog was ≥0.35 kU/l, or if there was a positive skin test response. When the 20 children with persistent childhood asthma (doctor-diagnosed asthma at all three control visits) were compared with the other 61 children, an early exposure to dog (OR = 0.14, p = 0.034)) decreased the asthma risk and an early sensitization to cat (OR = 5.92, p = 0.008) and dog (OR = 9.33, p = 0.001) increased the asthma risk. There were less cat and dog keeping in atopic families and the effect of sensitization was, but the effect of exposure was not, robust to adjustments in multivariate analyses. The present study demonstrates, in a long-term follow-up after early wheezing, that early sensitization to cat and dog increases the risk of later asthma but early exposure to cat or dog has no such effect. Dog keeping was less frequent in atopic families, which may explain that the protective effect of early exposure to dog was lost in multivariate analyses.     

The development of childhood asthma: lessons from the German Multicentre Allergy Study (MAS)

Epidemiological surveys have indicated that there has been a notable increase in the prevalence of both asthma and other allergic symptoms in children and young adults. Since it seems unlikely that genetic factors would contribute to the rising trend, environmental factors might play a major part in the development of childhood asthma. In a prospective birth-cohort study, we assessed the relevance of different exposures such as mite and cat allergen exposure, environmental tobacco smoke (ETS) exposure, early infectious diseases and vaccinations for the development of childhood asthma up to the age of 10 years. Data up to 7 years of age have been evaluated. Of 1314 newborn infants enrolled in five German cities in 1990, follow-up data at age 7 years were available for 939 children (72%). Assessments included repeated measurements of specific IgE to food and inhalant allergens, measurement of indoor allergen exposure at 6 months, 18 months and 3 years of age and yearly interviews by a paediatrician. At age 7 years, pulmonary function was tested and bronchial responsiveness was determined in 645 children. At age 7, the prevalence of wheezing in the past 12 months was 10% (94 out of 938), and 6.1% (57 out of 939) parents reported a doctor's diagnosis of asthma in their children. Sensitisation to indoor allergens was associated with asthma, wheeze and increased bronchial responsiveness. However, no relationship between early indoor allergen exposure and the prevalence of asthma, wheeze and bronchial responsiveness was seen. During the first 3 years of life, intra-uterine tobacco and consistent ETS exposure have an adjuvant effect on allergic sensitisation that is transient and restricted to children with a genetic predisposition for allergy. Children sensitised to any allergen early in life and sensitised to inhalant allergens by the age of 7 years were at a significantly increased risk of being asthmatic at this age (odds ratio (OR) = 10.12; 95% confidence interval (CI) = 3.81-26.88). Children with repeated episodes (> or =2) of runny nose before the age of 1 year were less likely to develop asthma by the age of 7 years (OR = 0.52; 95% CI = 0.29-0.92). Our data do not support the hypothesis that exposure to environmental allergens directly causes asthma in childhood but that induction of specific IgE responses and the development of childhood asthma are determined by independent factors. Indoor allergen avoidance is recommended as first line treatment in secondary and tertiary prevention; however, conclusions should be drawn with caution about the possible effect of primary preventative measures. Since allergic asthma seems to be a Th2-disease, immunomodulating factors such as early childhood infections, LPS-exposure or other factors influencing gene-environment interaction and individual susceptibility seem to be relevant for the development of childhood asthma.     

Domestic allergen and endotoxin exposure and allergic sensitization in Cyprus

We investigated the relationship between domestic allergen and endotoxin exposure and allergic sensitization among children in Cyprus. We skin prick tested 128 children aged 15-16 yr (random samples of 85 children with self-reported asthma and 43 healthy controls) and measured their domestic exposure to endotoxin and allergens (mite, cat, and dog). We analyzed the data using multivariate logistic regression (adjusting for gender, area of residence and parental history) and presented the outcomes as odds ratios (OR) and 95% confidence intervals (CI). Among this selected population, 19% of children were sensitized to mite, 15% to cat and 7% to dog. Male gender (OR 2.74, 95% CI 1.18-6.38, p = 0.02), maternal history of allergic disease (OR 3.53, 95% CI 1.13-11.00, p = 0.03), increasing endotoxin (OR 1.58, 95% CI 1.00-2.49, p = 0.05) and residence in the district of Nicosia (OR 2.48, 95% CI 1.01-6.08, p = 0.05) were independent associates of allergic sensitization. Factors associated with mite sensitization were increasing Der p 1 and endotoxin exposure (OR 1.28, 95% CI 1.01-1.62, p = 0.04 and OR 1.76, 95% CI 1.01-3.08, p = 0.05, respectively) and living in an urban area (OR 6.80, 95% CI 1.37-33.67, p = 0.02). Sensitization to domestic pets was associated only with paternal allergic disease (cat: OR 5.68, 95% CI 1.57-23.56, p = 0.02; dog: OR 13.5, 95% CI 1.79-101.73, p = 0.01), but not with pet ownership or specific allergen or endotoxin exposure. In conclusion, mite allergen exposure was associated with sensitization to mite, but there was no association between cat and dog allergen exposure and specific sensitizations. Surprisingly, in this area, increasing endotoxin exposure was associated with an increased risk of sensitization.     

Environmental exposures and exhaled nitric oxide in children with asthma

OBJECTIVE: To evaluate the relation of environmental factors with exhaled nitric oxide (FENO) concentrations among asthmatic children. STUDY DESIGN: Cross-sectional analysis of 170 tobacco smoke-exposed children, ages 6 to 12 years, who have doctor-diagnosed asthma using measures of FENO, medication use, and exposures to settled indoor allergens and tobacco smoke. RESULTS: In multivariable analysis, child's age, uncarpeted flooring, not owning a cat, higher income, dust mite exposure, and being sensitized to any allergens were associated with higher FENO concentrations. Children who were sensitized to indoor allergens had an adjusted geometric mean FENO of 15.4 ppb (95% CI, 13.1, 18.2) compared with 10 ppb (95% CI, 8.2, 12.2) for unsensitized children. There was no statistically significant association of serum cotinine, hair cotinine, or reported corticosteroid therapy with FENO. CONCLUSIONS: FENO is higher among children who are sensitized to indoor allergens and exposed to dust mites. The results hold promise for the use of FENO as a tool to manage childhood asthma by using both pharmacologic and environmental treatments.     

Socioeconomic Factors and Home Allergen Exposure in Children With Asthma

IntroductionThe objective of this study was to determine the association between sociodemographic factors and the elimination of allergen sources from homes of asthmatic children.MethodIn a cross-sectional analysis of data from 845 asthmatic children, multiple linear regression investigated the association between socioeconomic factors and failure to reduce allergen sources (i.e., stuffed toys, pets, carpeting, curtains, and cushions); failure to use linen covers; and not laundering linens weekly in hot water. Logistic regression assessed the relationship between socioeconomic status and exposure to environmental tobacco smoke.ResultsMother's employment status was significantly associated with the quality of the home environment (P = .0002). Homemakers demonstrated fewer poor practices (3.1) compared with full-time or part-time employed mothers (3.6). Children whose mothers reported no post-secondary education were more likely to have environmental tobacco smoke exposure compared with those who had a post-secondary CE education or higher (OR 2.4, 95% CI 1.7, 3.5).DiscussionChildren whose mothers worked at home and were better educated were at reduced risk for exposure to sources of indoor allergens.     

Risk factors for respiratory symptoms and atopic sensitisation in the Baltic area.

Recent studies have indicated that atopic sensitisation is uncommon while respiratory symptoms are common among schoolchildren in Eastern Europe. Risk factors for respiratory symptoms and atopic sensitisation were evaluated in a cross sectional study involving 2594 schoolchildren (10-12 years) from Sweden (n = 665), Poland (n = 410), and Estonia (n = 1519). The measurements included parental questionnaires and skin prick tests with eight standardised allergens. Multiple logistic analyses demonstrated that atopic heredity was a significant independent risk factor for respiratory symptoms and atopic sensitisation in all the countries. Current dampness and maternal smoking were related to respiratory symptoms whereas domestic crowding, male gender, and passive smoking during infancy were related to atopic sensitisation. Current maternal smoking had a strong dose response association with current coughing attacks (nocturnal cough > 4 weeks or exercise induced coughing attacks) but only in Eastern Europe. A strong inverse relationship was recorded between domestic crowding and sensitisation as the risk for sensitisation increased with decreasing number of persons per room in the household (odds ratio (OR) 0.58, 95% confidence interval (CI) 0.43 to 0.77). Exposure to tobacco smoke at home during infancy was a risk factor for atopic sensitisation but only to animal dander and only in Eastern Europe (OR 1.41, 95% CI 1.03 to 1.93). In conclusion, there were small differences in the pattern of risk factors between Eastern and Western Europe. The only exception was environmental tobacco smoke being a risk factor only in Eastern Europe. The study also suggests that factors related to domestic crowding protect against atopic sensitisation in Estonia and Poland. A higher standard of living with less crowding may give rise to an increasing prevalence of atopic sensitisation also in Eastern Europe.     

Childhood asthma and exposure to indoor allergens: lowmite levels are associated with sensitivity

The prevalence and level of sensitivity to indoor allergens were studied in relation to current exposure at home in 124 children with perennial asthma living in three climatic zones of Sweden. The house dust mite (HDM) allergen levels were higher in the South than in the North (p < 0.001), while cat and dog allergen levels tended to be higher in the North than the South (n. s.). Thirty-four percent of the children were sensitive to the HDM Dermatophagoides pteronyssinus , as determined by IgE antibodies in vitro, 27% were sensitive to D. farinae , 57% to cat and 55% to dog. Sensitivity to HDM was significantly more prevalent in Southern, than in Central and Northern Sweden (p=0.001) where the children were more often sensitive to pets (cat p=0.005, dog p= 0.002). A significant association between the concentration of Der p I and Derf I in the house dust and both the prevalence of sensitivity to HDM and the IgE antibody levels against mites was found even at concentrations well below the commonly suggested risk level for sensitisation of 2 μg/g dust. No relationship was found between pet allergen concentration in the home dust and sensitivity to pets, possibly because of exposure outside home, e. g. in schools and meeting places for leisure activities. Similarly, there was no consistent association between the level of mite or pet allergen exposure at home and asthma severity as judged by symptom and medication score. The study indicates that there is no threshold value for sensitisation to mite allergens in asthmatic children, and therefore, dust allergen levels at home should be kept as low as possible in homes of children at risk for asthma.     

Different sensitization profile for asthma, rhinitis, and eczema among 7-8-year-old children: Report from the Obstructive Lung Disease in Northern Sweden studies

Sensitization to different airborne allergens in relation to asthma, rhinitis, and eczema has been studied. A cross-sectional study was performed among 7–8-year-old children living in northern Sweden. The ISAAC-questionnaire with additional questions were sent to the parents, and 3431 (97%) participated. Two-thirds of the children were invited to undergo a skin test with 10 common airborne allergens, and 2148 (88%) participated. The prevalence rates of all three diseases were significantly higher among the children who were sensitized to any of the tested allergens. Among asthmatics, 40% were sensitized to cat, 34% to dog, 28% to horse, 23% to birch and 16% to timothy. The corresponding figures for rhinitis were: cat 49%, dog 33%, horse 37%, birch 46%, timothy 32%; and for eczema: cat 29%, dog 21%, horse 15%, birch 20%, and timothy 11%. Only a few children were sensitized to mites or moulds. The main risk factors for all three diseases were type-1 allergy and a family history of the disease. Independently from other risk factors, sensitization to dog (OR 2.4) and horse (OR 2.2) were significant risk factors for asthma. Sensitization to birch (OR 6.0), horse (OR 4.1), and timothy (OR 2.8) were significant risk factors for rhinitis, while birch (OR 2.4), dog (OR 2.0) and cat (OR 1.6) were significant risk factors for eczema. Despite a large over-lapping of the diseases the pattern of sensitization was different for asthma, rhinitis and eczema. Sensitization to cat was most common among all children, but sensitization to dog and horse was associated with the highest risk for asthma, and sensitization to birch showed the highest risk for rhinitis and eczema. The different risk factor pattern for the often coexisting diseases; asthma, rhinitis, and eczema, may indicate differences in the etiology.     

Indoor exposures and recurrent wheezing in infants: a study in the BAMSE cohort

Aim: The aim of this study was to examine the relationship between indoor exposures and the home environment, and the development of recurrent wheezing during infancy. Methods: A birth cohort, comprising 4089 children, was followed. Information on exposures was obtained shortly after birth, and episodes of wheezing were recorded when the infants were 1 and 2 y of age. In a nested case-control study, 181 infants were enrolled, who had three or more reported episodes of wheezing after 3 mo of age combined with either use of inhaled steroids or symptoms of bronchial hyper-reactivity, and 359 age-matched controls. Home inspections were performed during the winter following enrolment, and indoor conditions were measured. Results: Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated. The OR for recurrent infant wheezing associated with signs of dampness reported prospectively by parents was 1.4 (0.9-2.2), and the OR for observed signs of dampness at home inspections was 1.6 (1.0-2.5). A trend was found in the risk of recurrent wheezing in relation to the number of indicators of dampness: OR 1.3 (0.8-2.2) for one sign of dampness and OR 2.7 (1.3-5.4) for three or more signs of dampness. Newly painted surfaces in the child's bedroom was associated with an increased OR for recurrent wheezing: 1.7 (1.3-2.6).

Conclusion: Indicators of dampness, as well as recently repainted interior surfaces, appear to be associated with recurrent infant wheezing, with a strengthened effect of combined indoor exposures.     

Impact of Presence of Children on Indoor Tobacco Restrictions in Households of Urban and Rural Adult Tobacco Users

Objectives

Secondhand smoke exposure in children is changing as a result of new public policy and electronic nicotine products (e-cigarettes). We examined factors related to self-imposed indoor household tobacco restrictions, with emphasis on children in the household and associations with combustible and noncombustible product use.

Are influences during pregnancy associated with wheezing phenotypes during the first decade of life?

Aim: Recently, attention has focused on possible early life origins for asthma. We sought to identify whether factors present during pregnancy were associated with development of childhood wheezing phenotypes. Methods: A whole population birth cohort (n=1456) on the Isle of Wight, UK, was followed through to age 10 y. Where possible, information regarding environmental exposures and events during pregnancy was obtained from the maternity records (n=1238). Children were seen at ages 1, 2, 4 and 10 y, and wheezing symptoms were used to define wheezing phenotypes in the first decade (n=1034). Results: Risk of early-onsetpersistent wheeze (onset in the first 4 y, still present at age 10) was increased by environmental tobacco smoke exposure in pregnancy (OR=2.44; 95% CI: 1.37-4.34) plus maternal asthma (3.57; 1.84-6.94), but reduced by cat ownership (0.30; 0.13-0.62). Early transient wheeze (onset in the first 4 y, but not present at age 10) was increased by environmental tobacco smoke exposure (1.58; 1.02-2.45), male gender (1.68; 1.09-2.60) and low birthweight (3.65; 1.27-10.52). No environmental factors in pregnancy were associated with late-onset persistent wheeze (onset after age 4 y, still present at 10 y).

Conclusion: In addition to genetics, maternal exposures during pregnancy show association with childhood and especially early-life wheezing phenotypes.     

Effect of gestational and passive smoke exposure on ear infections in children

OBJECTIVE: To estimate the relative risk for otitis media (OM) in children from environmental tobacco smoke (passive exposure), maternal smoking during pregnancy (gestational exposure), or both. DESIGN: Analysis of data from a national cross-sectional health survey, utilizing questionnaire information and serum cotinine measurements. PARTICIPANTS: Children younger than 12 years (N = 11 728) in the Third National Health and Nutrition Examination Survey (NHANES III), conducted from 1988-1994. MAIN OUTCOME MEASURES: Occurrence and recurrence of ear infections. RESULTS: The cumulative incidence of ear infections was 69%. Of all participants, 38% were exposed to passive smoke, 23% were exposed to gestational smoke, and 19% were exposed to combined passive and gestational smoke. The occurrence of any ear infection was not increased by passive smoke exposure (adjusted risk ratio [RR], 1.01; 95% confidence interval [CI], 0.95-1.06), but was slightly increased by gestational (adjusted RR, 1.08; 95% CI, 1.01-1.14) and combined (adjusted RR, 1.07; 95% CI, 1.00-1.14) smoke exposures. The risk of recurrent ear infections (> or = 6 lifetime episodes) was significantly increased with combined smoke exposure (adjusted RR, 1.44; 95% CI, 1.11-1.81). Other risk factors for ear infection identified in multivariable analysis were race/ethnicity, poverty-income ratio of 2.00 or more, attendance in day care, history of asthma, and presence of allergic symptoms. CONCLUSIONS: Passive smoke exposure was not associated with an increased risk of ever developing an ear infection in this study. The increased risk found with gestational and combined smoke exposures has marginal clinical significance. For recurrent ear infections, however, combined smoke exposure had a clinically and statistically significant effect.     

Exposure to secondhand tobacco smoke and child behaviour – results from a cross-sectional study among preschool children in Bavaria

Aim:  To evaluate the association of postnatal exposure to secondhand tobacco smoke on childhood behavioural problems after taking maternal smoking during pregnancy into account.
Methods:  In a cross-sectional survey of preschool children in Bavaria, exposure to secondhand tobacco smoke in the child's home was assessed via a parent questionnaire. The Strength and Difficulties Questionnaire (SDQ) was applied to assess child's behaviour. The association with secondhand tobacco smoke exposure was assessed for 'probable' outcomes of the problem subscales and of prosocial behaviour.
Results:  Among 5494 children (48% female), the SDQ indicated behavioural problems in up to 11%. After adjustment for socioeconomic factors, low birth weight and maternal smoking before and during pregnancy, a dose-response relationship with exposure to secondhand tobacco smoke was observed regarding hyperactivity/inattention (odds ratio compared to 'none' was 1.35 for 'low/medium' and 2.39 for 'high' exposure, 95% confidence intervals 1.02–1.78 and 1.62–3.53, respectively) as well as for conduct problems (OR 1.68 (1.37–2.06) and 1.93 (1.39–2.68)).
Conclusion:  Secondhand tobacco smoke exposure at home appears to be associated with an increased risk of behavioural problems among preschool children. Prevention of behavioural problems may be a further reason to target secondhand tobacco smoke exposure in children.     

Allergens in urban schools and homes of children with asthma

To cite this article: Permaul P, Hoffman E, Fu C, Sheehan W, Baxi S, Gaffin J, Lane J, Bailey A, King E, Chapman M, Gold D, Phipatanakul W. Allergens in urban schools and homes of children with asthma. Pediatr Allergy Immunol 2012: 23: 543-549. ABSTRACT: Background: Most studies of indoor allergens have focused on the home environment. However, schools may be an important site of allergen exposure for children with asthma. We compared school allergen exposure to home exposure in a cohort of children with asthma. Correlations between settled dust and airborne allergen levels in classrooms were examined. Methods: Settled dust and airborne samples from 12 inner-city schools were analyzed for indoor allergens using multiplex array technology (MARIA). School samples were linked to students with asthma enrolled in the School Inner-City Asthma Study (SICAS). Settled dust samples from students' bedrooms were analyzed similarly. Results: From schools, 229 settled dust and 197 airborne samples were obtained. From homes, 118 settled dust samples were obtained. Linear mixed regression models of log-transformed variables showed significantly higher settled dust levels of mouse, cat and dog allergens in schools than homes (545% higher for Mus m 1, estimated absolute difference 0.55?μg/g, p?相似文献   

Environmental risk factors of rhinitis in early infancy

Previous studies of allergic rhinitis in children have not documented the environmental risk factors for infants at age one. We examined the relationship of environmental tobacco smoke (ETS) and visible mold exposures on the development of allergic rhinitis, rhinitis and upper respiratory infection (URI) in a birth cohort where at least one parent was skin prick test (SPT) positive. ETS exposure and upper respiratory symptoms were obtained by questionnaires. Visible mold was classified as none, low or high during home visit. Infants had a SPT at age one. After adjustment for potential confounders, exposure to >20 cigarettes per day was associated with an increased risk of developing allergic rhinitis at age one [odds ratio (OR)=2.7; 95% CI 1.04-6.8] and rhinitis symptoms during the first year (OR=1.9; 95% CI 1.1-3.2). Infants with low (OR=1.5; 95% CI 1.1-2.3) or high (OR=5.1; 95% CI 2.2-12.1) levels of visible mold in their homes were more likely to have more frequent URI during the first year. Older siblings were protective for development of both rhinitis symptoms and allergic rhinitis. This study suggests that ETS exposure, rather than visible mold, is associated with rhinitis and allergic rhinitis in infants. The analysis also suggests that mold may be a stronger risk factor for URI that ETS.     

Wheezing due to rhinovirus infection in infancy: Bronchial hyperresponsiveness at school age

Background: Characteristics related to decreased lung function and increased bronchial responsiveness after early childhood wheezing requiring hospitalization are not fully established.
Methods: Seventy-nine children with wheezing requiring hospitalization at age <2 years were prospectively followed up and re-investigated at age 5.6–8.8 years when the measurements of baseline lung function and bronchial responsiveness to exercise were performed.
Results: At early school age, 23% of children had decreased lung function, and 13% had increased bronchial responsiveness to exercise. Predictors of decreased lung function were maternal history of smoking during pregnancy (odds ratio [OR], 12.8; 95% confidence interval [CI]: 1.2–139.6), parental history of asthma (OR, 4.3; 95%CI: 1.1–17.1), and female gender (OR, 4.0; 95%CI: 1.2–13.7). Increased bronchial responsiveness was associated with rhinovirus infection-induced wheezing in infancy (OR, 6.5; 95%CI: 1.2–36.3), and early cat or dog exposure leading to sensitization (OR, 26.6; 95%CI: 1.3–525.2). Inhaled anti-inflammatory therapy was common in children with rhinovirus infection-induced wheezing in infancy ( n  = 13/19; P  = 0.001 vs children with other/no confirmed virus infection etiology for wheezing in infancy, n  = 16/60), which may have improved lung function and attenuated bronchial responsiveness in them.
Conclusions: After early childhood wheezing requiring hospitalization, one-fourth of children will have decreased lung function and one-eighth of children will show increased bronchial responsiveness at school age. Gender, heredity of asthma, and antenatal exposure to tobacco smoke are predictors of decreased lung function, whereas rhinovirus infection etiology of wheeze and early animal exposure leading to sensitization are associated with increased bronchial responsiveness later in childhood.