Day care attendance in early life,maternal history of asthma,and asthma at the age of 6 years

Among children not selected on the basis of a parental history of atopy, day care attendance in early life is inversely associated with asthma at school age. We examined the relation between day care in the first year of life and asthma, recurrent wheezing, and eczema at the age of 6 years and wheezing in the first 6 years of life among 453 children with parental history of atopy followed from birth. Among all study participants, day care in the first year of life was inversely associated with eczema (odds ratio [OR] = 0.3, 95% confidence interval [CI] = 0.1-0.8). Day care attendance in early life was associated with a decreased risk of asthma (OR = 0.3, 95% CI = 0.1-0.7) and recurrent wheezing (OR = 0.3, 95% CI = 0.1-0.9) at the age of 6 years and with a decreased risk of any wheezing after the age of 4 years only among children without maternal history of asthma. Among children with maternal history of asthma, day care in early life had no protective effect on asthma or recurrent wheezing at the age of 6 years but was instead associated with an increased risk of wheezing in the first 6 years of life. Our findings suggest that maternal history of asthma influences the relation between day care-related exposures and childhood asthma.     

A prospective study of Fel d1 and Der p1 exposure in infancy and childhood wheezing

The impact of domestic exposure to cat allergen (Fel d1) and house dust mite (Der p1) on wheezing from birth to the age of 4 years was investigated in a multicenter prospective birth cohort; 1,611 mothers were recruited before delivery in Ashford, England, and Barcelona and Menorca, Spain. Exposures were gathered via dust sample collection at children's home in their first year of life. Families provided complete outcome data (wheezing status in all 4 years) for 1,289 children. Domestic allergen levels varied substantially between centers. Six hundred three (47%) children never wheezed during their first 4 years of life. Der p1 did not correlate with any type of wheezing outcome. Fel d1 significantly increased the risk of wheezing in 3- and 4-year-olds in comparison to 1-year-olds. Distinct risk profiles were found for wheezing at different ages. Multivariate analysis revealed an interaction between Fel d1 and maternal asthma among children who wheeze in Year 4 (relative risk = 2.77; 95% confidence interval = 1.19-6.46). Our data support the idea that several patterns of wheezing with different risk profiles exist among young children. The effect of Fel d1 exposure varied according to age and maternal asthma.     

Maternal history, sensitization to allergens, and current wheezing, rhinitis, and eczema among children in Costa Rica

Little is known about the factors associated with asthma, allergic rhinitis, and eczema in Latin American countries. We investigated the relation between potential risk factors and current wheezing, allergic rhinitis, and eczema among 208 Costa Rican children aged 10-13 years participating in phase II of the International Study of Asthma and Allergies in Childhood (ISAAC). The geometric mean ( +/- SD) serum total IgE level of children with current wheezing was significantly higher than that of children without current wheezing (533.8 +/- 5.2 vs. 144.7 +/- 6.0 IU/mL, P < 0.01). In a multivariate analysis, a maternal history of asthma, skin test reactivity (STR) to house dust mites, and STR to Alternaria were significantly associated with current wheezing. Children who had a maternal history of asthma had 2.4 times higher odds of current wheezing than those without maternal history of asthma (95% CI for OR = 1.1-5.3). Sensitization to either house dust mite or Alternaria was associated with 3.3 times increased odds of current wheezing (95% CI for OR for STR to dust mite = 1.6-6.7; 95% CI for OR for STR to Alternaria = 1.1-11.0). In a multivariate analysis, STR to house dust mite and STR to cat dander were significantly associated with allergic rhinitis, and a maternal history of eczema and STR to dog dander were associated with eczema in the child. The interaction between familial factors and lifestyle changes resulting from social reforms implemented 60 years ago may explain the high prevalence of atopic diseases in Costa Rica.     

Association of birth weight with asthma-related outcomes at age 2 years

BACKGROUND: Although lower birth weight associated with prematurity raises the risk of asthma in childhood, few prospective studies have examined higher birth weight, and few have separated the two components of birth weight, fetal growth and length of gestation. OBJECTIVE: To examine the associations of fetal growth and length of gestation with asthma-related outcomes by age 2 years. METHODS: We studied 1,372 infants and toddlers born after 34 weeks' gestation in Project Viva, a prospective cohort study of pregnant mothers and their children. The main outcome measures were parent report of (1) any wheezing (or whistling in the chest) from birth to age 2 years, (2) recurrent wheezing during the first 2 years of life, and (3) doctor's diagnosis of asthma, wheeze or reactive airway disease ("asthma") by age 2. We calculated gestational age from the last menstrual period or ultrasound examination, and determined birth weight for gestational age z-value ("fetal growth") using US national reference data. RESULTS: Infants' mean birth weight was 3,527 (SD, 517; range, 1,559-5,528) grams. By age 2 years, 34% of children had any wheezing, 14% had recurrent wheezing, and 16% had doctor-diagnosed asthma. After adjusting for several parent, child, and household characteristics in logistic regression models, we found that infants with birth weight > or = 4,000 g were not more likely to have any wheezing (odds ratio (OR), 0.91; 95% confidence interval (CI): 0.62, 1.34) or doctor-diagnosed asthma (OR, 0.80; 95% CI: 0.49, 1.31) than infants with birth weight 3,500-3,999 g. In models examining length of gestation and fetal growth separately, neither the highest nor the lowest groups of either predictor were associated with the three outcomes. Boys had a higher incidence of asthma-related outcomes than girls, and exposure to passive smoking, parental history of asthma, and exposure to older siblings were all associated with greater risk of recurrent wheeze or asthma-related outcomes at age 2 years. CONCLUSION: Although male sex, exposure to smoking, parental history of asthma, and exposure to older siblings were associated with increased risk of wheezing and asthma-related outcomes in this prospective study of children born after 34 weeks gestation, fetal growth and length of gestation were not.     

Salivary cotinine levels in children presenting with wheezing to an emergency department

We set out to evaluate salivary cotinine concentrations to judge tobacco smoke exposure among infants and children, and to examine the results in relation to age and wheezing. This was a case-control study of wheezing children (n = 165) and children without respiratory tract symptoms (n = 106) who were enrolled in the Pediatric Emergency Department at the University of Virginia. The age range of both wheezing and control patients was 2 months to 16 years. Questionnaires were combined with cotinine assays in saliva to evaluate exposure to environmental tobacco smoke (ETS) for each child. The prevalence of exposure to one or more smokers at home was high (68%); and 43% of the children enrolled were exposed to ETS from their mothers. According to the questionnaires, and after adjusting for age and race, a wheezing child in this study was more likely than a control to be exposed to at least one smoker at home (odds ratio = 1.9; 95% CI = 1.1-3.4). However, the odds of exposure to ETS from smoking mothers did not differ significantly between wheezing and control patients, and no significant association was found between the presence of wheezing and salivary cotinine levels. Among children exposed to ETS at home, cotinine levels were significantly higher in saliva from those under the age of two years, and from toddlers aged 2 and 3 years, compared to values from children over age 4 years. Moreover, the number of smokers in the home strongly influenced cotinine levels from children under age 4 years. In addition, higher cotinine levels were observed in saliva from children under age 2 years who were exposed to ETS from their mothers. Cotinine levels were similar and significantly correlated in paired samples of saliva and serum from children under 4 years of age (n = 54), (r = 0.92, P < 0.001). Based on information gathered from questionnaires, the results indicate that wheezing children were more likely than controls to be exposed to ETS at home. However, significant differences in ETS exposure between wheezing and control groups with respect to maternal smoke exposure or comparisons of salivary cotinine levels were not apparent. It was clear that determinations of salivary cotinine for monitoring the prevalence and intensity of household smoke exposure in this study were most valuable during the first 4 years of life.     

Perinatal smoking exposure and risk of asthma in the first three years of life: A prospective prebirth cohort study

BackgroundThere is limited evidence on the association between prenatal smoking exposure and the risk of asthma in children. The aim of this prebirth cohort study was to investigate the association between prenatal and postnatal tobacco smoke exposure and the risk of asthma in Japanese children.MethodsStudy subjects were 1304 mother–child pairs. Information on the variables under study was obtained using repeated questionnaires that were completed by mothers, first prior to delivery, then shortly after birth and subsequently around 4, 12, 24, and 36 months after delivery. Ever asthma was defined as a maternal report of physician-diagnosed asthma at any time since birth. Current asthma was defined as the use of asthma medication at the time of the sixth survey.ResultsLogistic regression models revealed that maternal active smoking, either before pregnancy or during pregnancy, was not associated with the risk of ever asthma or current asthma. Further, no association was observed between postnatally living with at least one household smoker and the risk of asthma. Among children whose mothers are never smokers, maternal second-hand smoke (SHS) exposure at work and/or at home during pregnancy increased the risk of ever asthma and current asthma in children; adjusted odds ratio (95% confidence intervals) for ever asthma and current asthma were 2.41 (1.13–5.05) and 4.82 (1.68–13.43), respectively.ConclusionsOur findings suggest that maternal SHS exposure during pregnancy might be associated with an increased risk of ever asthma and current asthma in young children whose mothers have never smoked.     

Symptoms, lung function, and beta2-adrenoceptor polymorphisms in a birth cohort followed for 10 years

As little is known about the natural history of bronchial responsiveness and the development of wheezing symptoms in early childhood, a cohort of children at risk of allergy, whose lung function and bronchial responsiveness had been measured in the neonatal period, was followed prospectively for 10 (SD, 0.8) years in order to determine the role of neonatal measurements on wheezing history and later lung function. A potential role for beta-2 adrenoceptor (beta2AR) polymorphisms in these relationships was also sought as a secondary objective. Of the original 73 children, wheezing history was available in 65 (89%), and 49 (67%) attended the laboratory for physiological measurements and genotyping of beta2AR. Wheezing was categorized as occurring 1) only before the fourth birthday, 2) after the fourth birthday, or 3) never. No relation was seen between neonatal and later lung function. However, neonatal bronchial responsiveness predicted subsequent FEV1 (P = 0.03). Increased neonatal bronchial responsiveness was associated with transient wheeze <4 years but not with later wheeze. Neonatal V'maxFRC was reduced in those possessing Gln27 or Arg16 alleles, but there was no effect of beta2AR polymorphisms on FEV1 at 10 years. Wheeze after 4 years of age was typical of classical asthma, as it was strongly related to atopy and bronchial responsiveness at age 10. In conclusion, we confirmed the association of neonatal bronchial responsiveness with both early wheezing and later lung function. We also showed an influence of polymorphisms at both aa16 and aa27 on neonatal lung function. Wheezing beyond 4 years, typical of classical asthma, was unrelated to early measurements of lung function or bronchial responsiveness.     

Prenatal maternal alcohol consumption and hospitalization with asthma in childhood: a population-based follow-up study

BACKGROUND: Asthma may have a prenatal origin. We examined whether maternal alcohol consumption during pregnancy increases the risk of hospitalization with asthma in children. METHODS: We conducted a follow-up study on 10,440 singletons born at approximately 36 weeks of gestation or later to mothers attending midwife centers between April 1984 and April 1987 in Denmark. The mothers completed a questionnaire regarding lifestyle and socioeconomic factors, including alcohol consumption. The children were followed up through the Danish Hospital Discharge Registry. We determined the first hospitalization with a discharge diagnosis of asthma as recorded in the Danish Hospital Discharge Registry. RESULTS: Most pregnant women (81.5%) drank at least some alcohol during pregnancy, but only a few (2.1%) consumed 120 g or more per week. In total, 307 children were hospitalized at least once with a discharge diagnosis of asthma during follow-up (the cumulative incidence risk was 3.5% from birth to 12 years of age or the end of follow-up). After adjusting for maternal socioeconomic factors, dietary components, and other lifestyle factors, children whose mothers drank alcohol during pregnancy did not have an increased risk of hospitalization with asthma compared with the children of mothers who reported no alcohol consumption during pregnancy (adjusted incidence rate ratio, 0.95; 95% confidence interval, 0.70-1.29). Further analyses showed no association with the dose and type of alcohol or with binge drinking. CONCLUSIONS: The study provides no support for a causal link between maternal alcohol intake during pregnancy and asthma in childhood.     

Evaluation of asthmatic patients referred to jahrom hospital and clinic

Asthma is the most common chronic respiratory disease of children in the world. Serial studies in the world have showed an increased prevalence of bronchial asthma. In this study, the children younger than 12 years old referred to Jahrom hospital and clinic due to asthma were selected. We issued 100 questionnaires, according to International Study of Asthma and Allergies in Childhood (ISAAC) criteria and were completed by the physicians. The ratio of male to female was 1 to 9. The patients who were under the age of 4, 3 and 1 year were 82%, 60% and 15% respectively. Passive smoking was present in 56% of the patients, and 22% had pets at home like cat, dog or bird. Home dampness was present in 33%. Ninety percent of patients had used breast feeding during the first year of life. Seventy percent of patients had family history of asthma. Food allergy was present and could trigger asthma in 15%. The result of ISSAC questionnaire showed that during the last year wheezing was present in 10%, 6% had 1-3 attacks and 4% had 4-12 attacks. Sleep disturbance by wheezing had occurred in 5% but cough in 16%. Thirteen percent of patients had wheezing after exercise. In Jahrom town the climate is warm and dry. In this town asthma in children is more common among the children who are younger than 4 years old. The risk factor like smoking at home, pets and home dampness should be eliminated from their environment.     

Does early exposure or sensitization to inhalant allergens predict asthma in wheezing infants? A 20-year follow-up.

Early sensitization to inhaled allergens predicts later asthma and allergy until school age, but studies on early exposure have given conflicting results. The purpose of this study was to evaluate the association between early wheezing, early exposure, or sensitization to pets and pollens and later asthma or allergy until adulthood. We have prospectively followed-up a cohort of 83 infants hospitalized for bronchiolitis in 1981-1982. Cat and dog ownership (early exposure) and inhalant allergen-specific IgE measurements (early sensitization) were registered at <3 years of age. Later, asthma and allergy were evaluated repeatedly between 3 and 20 years of age. Twenty-eight children were exposed to pets in early life, and 8 children were sensitized to pets and 10 children were sensitized to pollens. Birth season and early exposure or sensitization to pets were not significantly associated with later asthma and allergy. Wheezing was present at 3-6 years of age in 8 of 10 children sensitized to pollens (OR, 5.07; 95% CI, 1.48-17.31 versus nonsensitized), and asthma was present in 4 of 9 children at 8.5-10 years of age (OR, 9.53; 95% CI, 2.01-45.54). In multivariate analyses, early sensitization predicted asthma until 13.5-16 years of age. Seasonal rhinoconjunctivitis was not significantly associated with early exposure or sensitization to pets or pollens. In wheezing infants, early sensitization to seasonal pollens predicts subsequent wheezing and asthma until adolescence. No association was found between early exposure and sensitization to pets and later outcome.     

The effect of parental smoking on presence of wheeze or airway hyper-responsiveness in New South Wales school children

Background and Aims : To assess accurately the effect of parental smoking on the respiratory health of New South Wales (NSW) school children, we obtained a large data set by pooling data from seven cross-sectional studies conducted in NSW between 1991 and 1993.
Methods : A random sample of 6394 children age eight to 11 years was studied. Respiratory symptoms, family history of asthma and parental smoking history were measured by questionnaire, atopy by skin prick test and airway hyper-responsiveness (AHR) by histamine inhalation test.
Results : In total, 58.3% of children had at least one parent who smoked; 38.5% were exposed to maternal smoking. After adjusting for potential confounders, such as atopy, parental history of asthma and bronchitis in the first two years, children who were exposed to maternal smoking had a significantly increased risk of recent wheeze but not of AHR (odds ratios 1.33; 95% CI: 1.2-1.5 and 1.00; 95% CI: 0.9-1.2).
Conclusions : The positive association with wheeze and the lack of an association with AHR suggests that exposure to parental smoking leads to wheezing, but does not increase airway responsiveness.     

Exposure to pets and the risk of allergic symptoms during the first 2 years of life.

BACKGROUND: Currently, there is a lack of consensus regarding the influence of household pets on the development of allergic diseases in childhood. OBJECTIVE: The aim of this birth cohort study was to analyze the relationship between pet ownership at time of birth and the prevalence of atopic diseases approximately 2 years later. METHODS: A few days after the delivery of their babies, we asked 3132 mothers of German nationality whether they kept household pets like dogs, cats, or birds. Two years later, we asked whether their children had developed bronchial asthma, eczema, or hay fever. We then used logistic regression models to analyze whether there was an association between the development of allergic reactions among the children and pet ownership at the time of birth. RESULTS: In families without a history of atopic disease, the prevalence of asthma and eczema among 2-year-old children was significantly lower in those families that owned a dog at the time the children were born (odds ratio [OR], 0.52; 95% confidence interval [CI], 0.33-0.83). In contrast, in families with a history of atopic disease, early dog exposure was associated with a higher prevalence of asthma and eczema in 2-year-old children (OR, 1.43; 95% CI, 0.95-2.15). Comparable analyses assessing the influence of cats and birds in the home showed no effect on the development of atopic diseases in early childhood. CONCLUSIONS: This study confirms the findings of several earlier studies suggesting a negative association between dog ownership and the development of atopic diseases in early childhood, although the effect was only observed in families without a history of atopic disorders.     

The effect of early child care attendance on childhood asthma and wheezing: A meta-analysis

Objective: Research evidence offers mixed results regarding the relationship between early child care attendance and childhood asthma and wheezing. A meta-analysis was conducted to synthesize the current research evidence of the association between early child care attendance and the risk of childhood asthma and wheezing. Method: Peer reviewed studies published from 1964–January 2017 were identified in MEDLINE, CINAL, and EMBASE using MeSH headings relevant to child care and asthma. Two investigators independently reviewed the selected articles from this search. All relevant articles that met our inclusion criteria were selected for further analysis. Data were extracted from studies that had sufficient data to analyze the odds of asthma or wheezing among children who attended child care. Results: The meta-analysis of 32 studies found that (1) early child care attendance is protective against asthma in children 3–5 years of age but not for children with asthma 6 years of age or older. (2) Early child care attendance increases the risk of wheezing among children 2 years of age or younger, but not the risk of wheezing for children over 2 years of age. Conclusions: This meta-analysis shows that early child care attendance is not significantly associated with the risk of asthma or wheeze in children 6 years of age or older.     

Early-life antibiotic use is associated with wheezing among children with high atopic risk: a prospective European study

Background: Little is known about the relationship between antibiotic use and asthma in the children with a higher risk of allergic sensitization. We examine the association between the use of specific therapeutic antibiotics in the first year of life and development of wheezing by 36 months among children with a higher risk of allergic sensitization. Methods: A multi-center prospective cohort study was conducted among children at high risk for allergic sensitization. A validated questionnaire was used to prospectively collect information on antibiotic use and potential risk factors for wheezing from parents or guardians of 606 children from three European countries at 6, 12, 24 and 36 months of age. Multivariate linear and logistic regression models were used to adjust for potential confounders and effect modifiers and to estimate the association of antibiotic use with the development of early childhood wheezing. Results: Of the antibiotics assessed, only macrolide use in the first year of life was associated with increasing risk for wheezing by 36 months, after adjusting for gender, socioeconomic status, breast feeding >6 months, tobacco smoke exposure, family history of asthma, and respiratory infection (RR?=?1.09; 95% CI 1.05–1.13). To avoid a bias by indication, we analyzed children with and without respiratory infection separately. Similar associations were observed for macrolides use in children who had no respiratory infection. Conclusions: In European children with a familial risk for allergic sensitization, we found a positive association between macrolide use in the first year of life and wheezing until 36 months old which was independent of the effect of respiratory infection.     

Asthma prevalence and risk factors in school children: The RESPIR longitudinal study

ObjectivesTo analyze the incidence of wheezing in the first six years of life; the prevalence of asthma at six years of age; and the associated risk factors, in a population from Valencia, Spain.MethodsA prospective longitudinal study was made of a cohort of 636 newborn infants, with follow-up of the clinical records and the completion of questionnaires up to the age of six years.ResultsThe prevalence of asthma at six years of age was 12.8%. Up until that age, 63% of the study population had experienced at least one episode of wheezing, and 35% had suffered recurrent wheezing (three or more episodes). Admission due to wheezing was associated to school asthma. The following risk factors were identified: atopic dermatitis (OR: 2.1; 95%CI: 1.2-3.5), the presence of at least one episode of wheezing in the first year (OR: 1.8; 95%CI: 1.1-2.9), prematurity (OR: 2.5; 95%CI: 1.2-5.1), and a family history of asthma (OR: 2.2; 95%CI: 1.2-4.1).ConclusionsThe prevalence of asthma at six years of age in our population is similar to that described in other longitudinal studies. An important increase is observed in the cumulative incidence of wheezing and of recurrent wheezing up to three years of age, followed by stabilization. The most relevant risk factors for developing asthma at six years were atopic dermatitis, wheezing during the first year, prematurity, and a family history of asthma. Full-term pregnancy and the minimization of respiratory infections at an early age could reduce the prevalence of asthma at six years of age in our population.     

The association between birth season and future development of childhood asthma

The aim of this study was to examine a possible association between birth season (date of birth) and future development of asthma in children. A case-control study was designed to include asthmatic children aged 2-7 years, living in the city of Beer-Sheva, in southern Israel, registered in one pediatric center. Controls were healthy children matched for age and registered at the same clinic. Demographic data, past medical history, and asthma history and severity were collected using the computerized medical charts and asthma registry. A structured telephone questionnaire was used to complete the data. Children with a history of prematurity or chronic significant illness were excluded from the study. Sixty-six children and 69 controls were enrolled in the study. There were significantly more males in the asthmatic group compared to controls (P = 0.003). History of bronchiolitis or recurrent wheezing episodes in the first year, family history of asthma, and Middle-Eastern origin were significantly more common among asthmatic children than controls (P < 0.001). Asthmatic children were more likely to be born between March and June and least likely to be born between October and December, compared to controls (P < 0.05). Multivariate logistic regression analysis revealed three variables to be independent significant risk factors for development of asthma: birth season between March and June, acute bronchiolitis or recurrent wheezing episodes during first year of life, and male gender. Birth season during late winter and spring is associated with asthma during childhood.     

Decreased physical activity among Head Start children with a history of wheezing: use of an accelerometer to measure activity

Asthma is a severe problem among inner city children, and recent evidence suggests that both allergen exposure and lifestyle can impact the disease early in childhood. This study was designed to investigate the association between physical activity and wheezing among a population of inner city children enrolling in Head Start. The parents of children aged 3-5 years responded to a questionnaire (N = 144) to determine the presence and severity of wheezing and asthma. Information was also gathered regarding home environment, food frequency, and presence of other allergic diseases. Serum was obtained to measure total IgE and specific IgE levels to common allergens. Height and weight for body mass index were recorded. Lastly, motion sensor wristwatches (Actiwatch) were worn continuously by a subset of these children (n = 54) for 6 or 7 days. Physical activity measured with the motion sensor was decreased among children with a history of wheezing. The significant differences involved those measures of activity relating to prolonged or sustained physical activity. The correlates of asthma associated with decreased levels of physical activity included: 1) a history of wheezing in the last 12 months, 2) the diagnosis of asthma, and 3) presentation to the emergency room in the last 12 months for wheezing or asthma. In a preschool-age population, decreased physical activity was observed among children with a history of asthma or wheezing. Decreased physical activity could contribute to persistence of asthma or put children at higher risk for obesity and other chronic diseases.     

Pulmonary Vascular Physiology and Pathophysiology

We performed a hospital-based study to examine a hypothesis that indoor air pollution was associated with acute asthma in young children living in Kuala Lumpur City. A total of 158 children aged 1 month to 5 years hospitalized for the first time for asthma were recruited as cases. Controls were 201 children of the same age group who were hospitalized for causes other than a respiratory illness. Information was obtained from mothers using a standardized questionnaire. Univariate analysis identified two indoor pollution variables as significant factors. Sharing a bedroom with an adult smoker and exposure to mosquito coil smoke at least three nights in a week were both associated with increased risk for asthma. Logistic regression analysis confirmed that sharing a bedroom with an adult smoker (OR = 1.91, 95% Cl 1.13, 3.21) and exposure to mosquito coil smoke (OR = 1.73, 95% Cl 1.02, 2.93) were independent risk factors. Other factors independently associated with acute asthma were previous history of allergy, history of asthma in first-degree relatives, low birth weight, and the presence of a coughing sibling. There was no association between asthma and exposure to kerosene stove, wood stove, aerosol mosquito repellent, type of housing, or crowding. We conclude that indoor air pollution is an avoidable factor in the increasing morbidity due to asthma in children in a tropical environment.     

Indoor Air Pollution and Asthma in Hospitalized Children in a Tropical Environment

We performed a hospital-based study to examine a hypothesis that indoor air pollution was associated with acute asthma in young children living in Kuala Lumpur City. A total of 158 children aged 1 month to 5 years hospitalized for the first time for asthma were recruited as cases. Controls were 201 children of the same age group who were hospitalized for causes other than a respiratory illness. Information was obtained from mothers using a standardized questionnaire. Univariate analysis identified two indoor pollution variables as significant factors. Sharing a bedroom with an adult smoker and exposure to mosquito coil smoke at least three nights in a week were both associated with increased risk for asthma. Logistic regression analysis confirmed that sharing a bedroom with an adult smoker (OR = 1.91, 95% Cl 1.13, 3.21) and exposure to mosquito coil smoke (OR = 1.73, 95% Cl 1.02, 2.93) were independent risk factors. Other factors independently associated with acute asthma were previous history of allergy, history of asthma in first-degree relatives, low birth weight, and the presence of a coughing sibling. There was no association between asthma and exposure to kerosene stove, wood stove, aerosol mosquito repellent, type of housing, or crowding. We conclude that indoor air pollution is an avoidable factor in the increasing morbidity due to asthma in children in a tropical environment.