Outcome of long-term hospitalization for asthma in children

Children whose asthma continues to be poorly controlled with outpatient management are often referred to a long-term hospital program for care. Although these programs have been in existence since the 1950s, there has been no systematic study of their effectiveness. The purpose of the present study was to determine outcome in 103 children discharged consecutively after a long-term hospitalization. These children had both severe asthma and significant psychologic problems. Eighty-three of the 103 children had required continuous or frequent intermittent steroids for asthma control. In the year before admission, they had been hospitalized for asthma a mean of 2.6 times for 11.8 days and had had 4.6 visits to emergency rooms and 6.6 visits to physician offices for acute wheezing. Use of medical resources for asthma decreased significantly in the year after long-term hospitalization compared to the year before hospitalization (hospitalization: -34%, p less than 0.0001; hospital days: -39%, p less than 0.0002; emergency room visits: -46%, p less than 0.00001; physician office visits for acute asthma, -42%; p less than 0.00001; and a composite score giving increasing weight to more intensive and costly care: -30%, p less than 0.0001). Long-term hospitalization for children with asthma not responsive to outpatient management is associated with improvement in their use of medical resources.     

Caesarean section increases the risk of hospital care in childhood for asthma and gastroenteritis

OBJECTIVE: To investigate if caesarean section (CS) increases the risk for childhood asthma and gastroenteritis with reference made to children born with vaginal delivery (VD). METHODS: Retrospective study of data from linked Swedish medical service registers--Medical Birth Registry (MBR) and Hospital Discharge Registry (HDR). Data were obtained from women without any background/perinatal morbidity noted, and from children without any neonatal complications. Children that had reached at least 1 year of age and were found in the HDR were considered as cases, whereas children not found in the HDR or hospitalized for other causes than asthma or gastroenteritis were defined as controls. Odds ratios (OR) stratified for year of birth, maternal age, parity and smoking in early pregnancy were calculated. Investigations were made comparing the risk for in hospital treatment for asthma or gastroenteritis in CS children and in VD siblings of CS children. The overall inpatient morbidity in CS and VD children were also investigated. RESULTS: The OR for asthma in CS children was 1.31 [95% confidence interval (CI) 1.23-1.40]. The same OR, 1.31, was found for gastroenteritis (95% CI 1.24-1.38). The OR for CS children having experienced both asthma and gastroenteritis was further increased (1.74, 95% CI 1.36-2.23). The risk for asthma in VD siblings of CS children was not significantly increased, whereas VD siblings experienced a slightly increased risk for gastroenteritis. CS children had an increased overall in hospital morbidity when compared to VD children. CONCLUSION: There is a significant increase of the risk for developing symptoms of asthma and/or gastroenteritis that motivates admission for hospital care in CS children older than 1 year. It is speculated that a disturbed intestinal colonization pattern in CS children may be a common pathogenic factor.     

Does the use of antibiotics in early childhood increase the risk of asthma and allergic disease?

BACKGROUND: One of the mechanisms evoked to explain the increasing prevalences of asthma and allergy, in particular among children, is the 'Western lifestyle' or 'hygiene' hypothesis. As early childhood infections are assumed to hold a protective effect on the development of asthma and allergies, the use of antibiotics at that sensitive age may lead to an increased risk of asthma and allergy. OBJECTIVE: The aim of this study is to investigate the association between the use of antibiotics in the first year of life and the subsequent development of asthma and allergic disorders. METHODS: In a population-based sample of 7-and-8-year-old children questionnaire and skin prick test data were collected from 1206 and 675 subjects, respectively. Prevalence rates of asthma, allergic disorders and skin test positivity were compared between children with and without early life use of antibiotics, taking into account other possible risk factors including early respiratory infections. The effect of genetic predisposition was investigated by stratified analyses of children with and without parental hay fever. RESULTS: The use of antibiotics during the first year of life was significantly associated with asthma (OR = 1.7, 95% CI 1.0-3.1), hay fever (OR = 2.3, 95% CI 1.3-3.8) and eczema (OR = 1.3, 95% CI 1.0-1.8). No significant relationship was found with skin test positivity (OR = 1.1, 95% CI 0.7-1.7). After stratification for the presence of parental hay fever, children without parental hay fever did not show any significant associations between antibiotics use and asthma or allergy, whereas in children with parental hay fever the use of antibiotics was significantly related with asthma (OR = 2.3, 95% CI 1.1-5.1), hay fever (OR = 2.8, 95% CI 1.5-5.1) and eczema (OR = 1.6, 95% CI 1.0-2.6), and of borderline statistical significance with skin test positivity (OR = 1.6, 95% CI 0.9-3.0). CONCLUSION: Early childhood use of antibiotics is associated with an increased risk of developing asthma and allergic disorders in children who are predisposed to atopic immune responses. These findings support recent immunological understanding of the maturation of the immune system.     

Predictors of indoor exposure to mouse allergen in urban and suburban homes in Boston

BACKGROUND: Mouse allergen exposure is prevalent among urban children with asthma. Little is known about mouse allergen exposure in children at risk for the development of allergic diseases. AIMS OF THE STUDY: To assess indoor mouse allergen exposure in early life among children with parental history of asthma or allergies. METHODS: Prospective birth cohort study of 498 children with a history of allergy or asthma in at least one parent living in metropolitan Boston. RESULTS: Of the 498 participating children, 357 (71.7%) resided outside the city of Boston and 439 (90.7%) lived in households with incomes > 30,000 dollars. Mouse allergen was detected in 42% of the homes of study participants. In a multivariate analysis adjusting for sex, income, and endotoxin, black race [odds ratio (OR) = 3.0; 95% confidence interval (CI) = 1.3-6.6, P = 0.009], signs of mice in the home at age 2-3 months (OR = 3.0; 95% CI = 1.6-5.6, P = 0.0006), and kitchen cockroach allergen levels > or = 0.05 to < 2 U/g (OR = 1.8; 95% CI = 1.1-3.2, P = 0.02) were associated with detectable mouse allergen in the kitchen. In this model, living in a single detached house was inversely associated with detectable kitchen mouse allergen levels (OR = 0.4; 95% CI = 0.2-0.6, P = 0.0001). CONCLUSION: Infants with a parental history of asthma or allergies are commonly exposed to mouse allergen in their homes. Among infants at high risk for atopy, predictors of increased mouse allergen levels included black race, reported mice exposure, and moderate levels of cockroach allergen.     

Increased risk of asthma attacks and emergency visits among asthma patients with allergic rhinitis: a subgroup analysis of the improving asthma control trial

BACKGROUND: Inadequately controlled allergic rhinitis (AR) in asthmatic patients can contribute towards increased asthma exacerbations and poorer symptom control, which may increase medical resource use. We assessed asthma-related medical resource use and attacks in asthmatic patients who did and did not have concomitant AR and were adding montelukast or salmeterol to baseline treatment with inhaled fluticasone. METHODS: A post hoc resource use analysis of a 52-week, double-blind multicentre clinical trial (Investigation of Montelukast as a Partner Agent for Complementary Therapy) [corrected] including 1490 adults with chronic asthma, aged 15-72 years, with FEV(1) 50-90% of predicted and > or =12% increase in FEV(1) after salbutamol administration, treated with either montelukast 10 mg daily or salmeterol 50 microg twice daily in addition to fluticasone 200 microg, was undertaken. Asthma-related medical resource use included medical visits (defined as either an unscheduled visit [to a general practitioner, a specialist or a non-medical provider] or a specialist visit), emergency room visits and hospitalizations during follow-up. Asthma attacks were defined as the worsening of asthma requiring unscheduled visit, emergency visit, hospitalization or oral/intravenous/intramuscular corticosteroids. RESULTS: A self-reported history of concomitant AR was identified in 60% of the patients (n=893). Univariate analysis suggests that significantly more patients with concomitant AR experienced emergency room visits (3.6% vs. 1.7%, P=0.029) and asthma attacks (21.3% vs. 17.1%, P=0.046). Multivariate analysis adjusting for treatment group, age and baseline asthma severity confirmed these results since the presence of concomitant AR in patients with asthma increases the likelihood of emergency room visit (odds ratio (OR)=2.35, 95% confidence interval (CI)=1.12-4.80) and asthma attack (OR=1.35, 95% CI=1.03-1.77). Patients with asthma alone compared with patients with both conditions did not differ in terms of unscheduled or specialist visits and hospitalizations. CONCLUSIONS: Presence of self-reported concomitant AR in patients with asthma resulted in a higher rate of asthma attacks and more emergency room visits compared with asthma patients without concomitant AR.     

Why are some children with early onset of asthma getting better over the years? - Diagnostic failure or salutogenetic factors

Among children earlier having been identified with a hospital or primary care diagnosis of asthma at least once between 0-7 years of age, almost 40 % of their parents reported in the ISAAC-questionnaire as never having had asthma (NA). These are further analysed and compared with the persisting asthma cases (A) in this study. All these children''s medical records were scrutinized concerning their asthma diagnose retrospectively.The aim of this study was to analyse possible factors related to the outcome in an Asthma diagnosis reassessment by parental questionnaire at the age of ten of the children earlier having been identified with a hospital or primary health care diagnosis of asthma at least once between 0-7 years of age in a total birth-year cohort in a defined Swedish geographical area.A multiple logistic analysis revealed four significant and independent factors associated to the improvement/non-report of asthma at the age of ten. These factors were; not having any past experiences of allergic symptoms (p<0.0001), only having one or two visits at the hospital for asthma diagnosis in the 0-7 interval (p=0.001), not living in a flat but a villa at the age of ten (p=0.029) and no previous perception of mist or mould damage in the house (p=0.052).In the early postnatal stage, obstructive and bronchospastic symptoms typical of asthma may be unspecific, and those cases not continuing to persisting disease tend to have identifiable salutogenetic factors of constitutional rather than environmental nature, namely, an overall reduced allergic predisposition.     

Antibiotic use in early childhood and the development of asthma

BACKGROUND AND OBJECTIVE: Recent investigations have focused on the role of infections in infancy in promoting or protecting against the subsequent development of asthma. A related hypothesis concerns the possible role of medical responses to infections, including the widespread use of antibiotics. We chose children at Rudolf Steiner schools to test this latter hypothesis because a significant proportion of parents rejects the use of conventional treatments, including antibiotics. METHODS: Seventy-five per cent (n = 456) of parents of children aged 5-10 years attending Rudolf Steiner schools throughout New Zealand completed questionnaires which included questions on the use of antibiotics and a history of asthma and wheeze in their children. RESULTS: After controlling for potential confounders, antibiotic use was significantly associated with having a history of asthma (OR = 2.74, 95% CI: 1.10-6.85) or wheeze (OR = 1. 86, 95% CI: 1.06-3.26) but not with current wheeze (OR = 1.08, 95% CI: 0.54-2-16). The adjusted odds ratio for asthma was 4.05 (95% CI: 1.55-10.59) if antibiotics were used in the first year of life and 1. 64 (95% CI: 0.60-4.46) if antibiotics had been used only after the first year of life when compared with children who had never used antibiotics. The number of courses of antibiotics during the first year of life was also associated with increased odds ratios for asthma: 2.27 (95% CI: 1.14-4.51) for one to two courses and 4.02 (95% CI: 1.57-10.31) for three or more courses when compared with no antibiotic use in the first year of life. Although not significant, the association of antibiotics and hay fever (OR = 1.99 [95% CI: 0. 93-4.26]) was of a similar strength to the association of antibiotics with a history of wheeze. Antibiotics were not significantly associated with eczema (OR = 1.23 [95% CI: 0.71-2.13]). CONCLUSION: Antibiotic use in infancy may be associated with an increased risk of developing asthma. Further study is required to determine the reasons for this association.     

Maternal fish intake during pregnancy and atopy and asthma in infancy

BACKGROUND: There is growing evidence that n-3 fatty acids have anti-inflammatory properties and may modulate immune response. Dietary intake of these nutrients during pregnancy could play a role in the risk of asthma and atopy in the offspring. METHODS: Using data from a cohort of women (n=462) enrolled during pregnancy and whose offspring were followed up to 6 years, we evaluated the impact of fish consumption during pregnancy on the incidence of atopy and asthma. Dietary intake was assessed by food frequency questionnaire (42 items) applied by an interviewer. RESULTS: Thirty-four percent of infants had a medical diagnosis of eczema at age 1 year, 14.3% of the children were atopic [based on skin prick test (SPT) at 6 years], and 5.7% had atopic wheeze at age 6 years. After adjusting for potential confounding factors, fish intake during pregnancy was protective against the risk of eczema at age 1 year, a positive SPT for house dust mite at age 6 years and atopic wheeze at age 6 years [odds ratio (OR)=0.73 95% confidence interval (CI) 0.55-0.98, OR=0.68, 95% CI 0.46-1.01 and OR=0.55, 95% CI 0.31-0.96, respectively]. For an increase in fish intake from once per week to 2.5 times per week, the risk of eczema at age 1 year decreased by 37%, and the risk of positive SPT at age 6 years by 35%. Stratification by breastfeeding showed that fish intake was significantly related to a decrease risk in persistent wheeze among non-breastfed children (P for interaction<0.05). No protective effect was observed among breastfed children. CONCLUSION: Our data suggest a protective effect of fish intake during pregnancy on the risk of atopy-related outcomes.     

Caesarean section delivery and the risk of allergic disorders in childhood

BACKGROUND: The composition of the intestinal flora in young children, if unfavourable, may increase the susceptibility to allergic disorders. Beneficial intestinal microbes originate from the maternal vaginal tract and thus are more likely to be transferred during vaginal births than during Caesarean sections (C-sections). OBJECTIVE: To determine whether children born by C-section have a different risk of allergic disorders compared with those delivered vaginally. We also tested the hypothesis that the risk of allergic disorders is highest for children born after 'repeat C-sections'. METHODS: A retrospective cohort study of 8,953 children aged 3-10 years. Children diagnosed with allergic rhinoconjunctivitis (AR), asthma, atopic dermatitis (AD), or food allergies were identified from the Kaiser Permanente Northwest Region electronic records. The children's sex, birth weight, birth order, postnatal exposure to antibiotics as well as the mothers' age, ethnicity, education, marital status, smoking status during pregnancy, and use of asthma or hayfever medications were identified through the mothers' medical records or through the Oregon Birth Registry. RESULTS: The risk of being diagnosed with AR was significantly higher in the children born by C-section than in those delivered vaginally: adjusted odds ratio (OR)=1.37%, 95% confidence interval (CI)=1.14-1.63. Delivery by C-section was also associated with the subsequent diagnosis of asthma (OR=1.24%, 95% CI=1.01-1.53); this association was gender specific, with a positive association restricted to girls (OR for asthma in girls: OR=1.53%, 95% CI=1.11-2.10; in boys: OR=1.08%, 95% CI=0.81-1.43). There was no significant association between mode of delivery and AD. If children born in a 'repeat C-section' were considered separately the risk of being diagnosed with AR increased further (OR=1.78%, 95% CI=1.34-2.37). The same increase was noted for asthma in girls (OR=1.83%, 95% CI=1.13-2.97) but not in boys. CONCLUSION: Caesarean sections may be associated with an increased risk of developing AR in childhood.     

Mouse exposure and wheeze in the first year of life.

BACKGROUND: Studies have found that exposure to mice is highly prevalent among children with asthma living in urban areas. OBJECTIVE: To examine the relationship between exposure to mice and wheeze in the first year of life. METHODS: We conducted an ongoing prospective birth cohort study of 498 children with a history of allergy or asthma in at least 1 parent living in metropolitan Boston (the Home Allergens and Asthma Study). RESULTS: In a multivariate analysis, infants whose parents reported exposure to mice in the household had nearly twice the odds of developing any wheeze in the first year of life as children without exposure (odds ratio [OR], 1.83; 95% confidence interval [CI], 1.14-2.95; P = .01). Other variables associated with wheeze in the first year of life included low birth weight (OR, 1.77; 95% CI, 1.06-2.95; P = .03), having at least 1 lower respiratory tract illness (OR, 5.59; 95% CI, 3.46-9.04; P < .001), exposure to high levels of endotoxin at age 2 to 3 months (fourth quartile compared with first quartile: OR, 2.32; 95% CI, 1.19-4.54; P = .01), and exposure to cockroach allergen of 0.05 U/g of dust or more at age 2 to 3 months (OR, 1.83; 95% CI, 1.09-3.08; P = .02). CONCLUSION: Among children with a parental history of asthma or allergies, exposure to mice is associated with wheeze in the first year of life, independent of other factors.     

Identifying asthma exacerbations in a pediatric emergency department: a feasibility study

BACKGROUND: Asthma is a common pediatric chronic disease and is estimated to account for more than 2million emergency department visits per year. Asthma guidelines have demonstrated improved outcomes, but remain underutilized due to several barriers. Computerized methods to automatically identify asthma exacerbations may be beneficial to initiate guideline recommended treatment, but have not been described. The goal of the study was to examine the accuracy of an algorithm to identify asthma patients at triage in real-time using only electronically available data. METHODS: During a 9-month period, the five most frequent presenting chief complaints for Emergency Department asthma patients aged 2-18 years were identified and accounted for >95% of asthma visits: wheezing, shortness of breath, fever, cough, and dyspnea. During a following 1-month period (November 2004), medical records of all patients with one of the five chief complaints were reviewed to establish a reference standard diagnosis. An asthma identification algorithm was developed that considered only data available in electronic format at the time of triage and included the presenting chief complaint, information from the computerized problem list (past medical history; current medications, such as beta-agonists, steroids, and other asthma medications), and ICD-9 billing codes from previous encounters. RESULTS: From 1835 Emergency Department visits, 368 visits (154 with asthma) had one of the five chief complaints and were included. A problem list was available in 203 (55.2%) and an ICD-9 code in 68 (18.5%) patients. Wheezing accounted for 56.5% of asthma visits, while fever was the most frequent chief complaint among all patients (43.8%). The asthma identification algorithm had a sensitivity of 44.8% (95% CI: 36.8-53.0%), a specificity of 91.6% (CI: 87.0-94.9%), a positive predictive value of 79.3% (CI: 69.3-87.3%) and a negative predictive value of 69.8% (CI: 64.0-75.1%). The positive and negative likelihood ratios were 5.3 (CI: 3.3-8.6) and 0.6 (CI: 0.5-0.7), respectively. CONCLUSION: The simple identification algorithm demonstrated good accuracy for identifying asthma episodes. The algorithm may represent a promising and feasible approach to create computerized reminders or automatic triggers that can facilitate the initiation of guideline-based asthma treatment in the Emergency Department.     

Predictors of repeat visits to the emergency room by asthmatic children in primary care

BACKGROUND: Subsets of asthmatic children, particularly in the Caribbean, burden the health system through repeated emergency room (ER) visits. We examined children to determine predictors of repeated ER visits in Trinidad. METHODS: Caregivers of 300 asthmatic children in primary healthcare in Trinidad reported on perceived factors of exacerbated wheeze requiring ER services. RESULTS: Prevalence of ER utilization in the past 12 months was 59.7% and 40.3% for repeated visits. Average age of wheezing onset was 2.8 (SD = 2.5) years. From the logistic regression analyses, independent predictors of repeat ER visits were mothers with a history of asthma (OR = 2.0, 95%Cl = 1.0-4.0), exposure to perfumes/odors (OR = 2.4, 95% Cl = 1.4-4.2), using inhaled corticosteroids (ICS) (OR = 2.2, 95% Cl = 1.2-4.0), and young age group (1-5 vs. 13-16 years) (OR = 2.7, 95% Cl = 1.1-6.4). More 1-5 year-olds (63.8%) and 6-12-year-olds (60.2%) wheezed in the dry and wet seasons, respectively (p = 0.04). Follow-up was poor (32.3%), and disease management did not include educational interventions. CONCLUSIONS: Repeated ER use in pediatric asthma underscores a pressing need for health providers and caregivers to develop an asthma management plan noting the identified predictors to assist in reducing Trinidad's asthma burden.     

Outcome of short-term hospitalization for children with severe asthma.

This study presents results of a family-centered, short-term residential program in which medical, behavioral, and treatment assessments were provided to the child with severe asthma and the family. After a median stay of 15 days, forty-four consecutively admitted children with severe asthma achieved a 93% reduction in hospital days (median, 7 hospital days for the year before treatment versus median 0 hospital days per patient per year at 20 1/2-month follow-up; p less than 0.001) and an 81% reduction in emergency care (median, 4 visits for the year previously versus median, 0.4 visits per patient per year at follow-up; p less than 0.01). There was also a significant reduction in corticosteroid bursts and improvement in FEV1. Unique to this program was mandatory family participation focusing on the child's and family's adaptation to severe asthma and development of family-specific interventions to promote compliance with the treatment regimen. Child and family functioning was assessed at admission and follow-up. Hospital use at follow-up was greater for children from dysfunctional families. Families demonstrating difficulties in disciplining the child with asthma required more hospital days both before admission and at follow-up. Short-term hospitalization for children with severe asthma is associated with significant improvement in pulmonary morbidity when the family of the child is included in assessment and treatment.     

Psychiatric morbidity is related to parental age: a national cohort study

BACKGROUND: The median age at first childbirth has increased dramatically in many high-income countries during the past decades. The psychiatric consequences of this demographic change are insufficiently described on a population level. This study aimed to investigate whether parental age at childbearing is related to psychiatric morbidity among Swedish youths. METHOD: This was a cohort study based on Swedish national registers. A national cohort of 292129 children born to primiparas women during 1973-1979 was followed prospectively from 1987 to 2002 in registers. Multivariate Cox analyses of proportional hazards were used to estimate the relative risk of hospital admission for schizophrenia, alcohol and illicit drug abuse, suicide attempts and deaths. RESULTS: Youths born of teenage mothers had a high risk for suicide death [relative risk (RR) 1.9, 95% confidence interval (CI) 1.3-2.7] and hospital admissions because of suicide attempt (RR 2.0, 95% CI 1.7-2.3) and substance abuse (alcohol: RR 1.6, 95% CI 1.4-1.8; illicit drug: RR 2.2, 95% CI 1.9-2.5) after adjustments for major sociodemographic confounders, compared with children of mothers aged 25-29 years. Offspring of older parents (>34 years) had the highest risk for schizophrenia (RR 1.8, 95% CI 1.0-3.0). CONCLUSIONS: Parental age is related to psychiatric morbidity.     

Genetic polymorphisms in arginase I and II and childhood asthma and atopy

BACKGROUND: A recent microarray study implicated arginase I (ARG1) and arginase II (ARG2) in mouse allergic asthma models and human asthma. OBJECTIVES: To examine the association between genetic variation in ARG1 and ARG2 and childhood asthma and atopy risk. METHODS: We enrolled 433 case-parent triads, consisting of patients with asthma 4 to 17 years old and their biologic parents, from the allergy clinic of a public hospital in Mexico City between 1998 and 2003. Atopy to 24 aeroallergens was determined by skin prick tests. We genotyped 4 single nucleotide polymorphisms (SNPs) of ARG1 and 4 SNPs of ARG2 with minor allele frequencies higher than 10% by using the TaqMan assay (Roche Molecular Systems, Pleasanton, Calif). RESULTS: ARG1 SNPs and haplotypes were not associated with asthma, but all 4 ARG1 SNPs were associated with the number of positive skin tests (P = .007-.018). Carrying 2 copies of minor alleles for either of 2 highly associated ARG2 SNPs was associated with a statistically significant increased relative risk (RR) of asthma (1.5, 95% CI = 1.1-2.1 for arg2s1; RR = 1.6, 95% CI = 1.1-2.3 for arg2s2). The association was slightly stronger among children with a smoking parent (arg2s1 RR = 2.1, 95% CI = 1.2 - 3.9 with a smoking parent; RR = 1.2, 95% CI = 0.8-1.9 without; interaction P = .025). Haplotype analyses reduced the sample size but supported the single SNP results. One ARG2 SNP was related to the number of positive skin tests (P = .027). CONCLUSION: Variation in arginase genes may contribute to asthma and atopy in children.     

Temporal change in the prevalence of respiratory symptoms and obstructive airways disease 1993–2001

BACKGROUND: There has been little available information regarding secular changes in the prevalence of respiratory symptoms since the mid-1990s. AIM: To examine changes in the prevalence of respiratory symptoms for 1993-2001. DESIGN OF STUDY: A series of postal questionnaire surveys. SETTING: Two general practice populations, including all age groups. METHOD: Four postal respiratory questionnaire surveys were conducted between 1993 and 2001. Subjects who replied to two or more surveys (8058 adults and 2350 children) were included in the main analyses. Validated scoring systems were used to define obstructive airways disease in adults and asthma in children. RESULTS: Over the 8-year observation period there were increases among adults in the crude prevalence of wheeze, being woken by cough, receipt of current asthma medication, and of obstructive airways disease, compared with decreases in children for wheeze, night cough, asthma attacks, and asthma. For adults, adjusted odds ratios per year of secular increase were 1.03 (95% confidence interval [CI] = 1.02 to 1.03) for wheeze, 1.03 (95% CI = 1.02 to 1.03) for being woken by cough, 1.03 (95% CI = 1.02 to 1.04) for asthma medication, and 1.02 (95% CI = 1.01 to 1.03) for obstructive airways disease. These increases were greater in those aged over 44 years, in males, and in those without a family history of asthma or a history of hayfever or eczema. Corresponding decreases for children were 0.94 (95% CI = 0.92 to 0.97) for wheeze, 0.93 (95% CI = 0.91 to 0.96) for night cough, 0.93 (95% CI = 0.90 to 0.95) for asthma attacks and 0.98 (95% CI = 0.95 to 1.00) for asthma. CONCLUSION: The increases found in adults are more likely to be due to chronic obstructive pulmonary disease (COPD) than asthma. This is supported by the decreases in symptom and asthma prevalence in children.     

Exposure to dust mite allergen and endotoxin in early life and asthma and atopy in childhood

BACKGROUND: There has been no longitudinal study of the relation between concurrent exposure to dust mite allergen and endotoxin in early life and asthma and atopy at school age. OBJECTIVES: To examine the relation between exposure to dust mite allergen and endotoxin at age 2 to 3 months and asthma, wheeze, and atopy in high-risk children. METHODS: Birth cohort study of 440 children with parental history of atopy in the Boston metropolitan area. RESULTS: In multivariate analyses, early exposure to high levels of dust mite allergen (> or =10 microg/g) was associated with increased risks of asthma at age 7 years (odds ratio [OR], 3.0; 95% CI, 1.1-7.9) and late-onset wheeze (OR, 5.0; 95% CI, 1.5-16.4). Exposure to endotoxin levels above the lowest quartile at age 2 to 3 months was associated with reduced odds of atopy at school age (OR, 0.5; 95% CI, 0.2-0.9). In contrast with its inverse association with atopy, endotoxin exposure in early life was associated with an increased risk of any wheeze between ages 1 and 7 years that did not change significantly with time (hazard ratio for each quartile increment in endotoxin levels, 1.23; 95% CI, 1.07-1.43). CONCLUSION: Among children at risk of atopy, early exposure to high levels of dust mite allergen is associated with increased risks of asthma and late-onset wheeze. In these children, endotoxin exposure is associated with a reduced risk of atopy but an increased risk of wheeze. CLINICAL IMPLICATIONS: Early endotoxin exposure may be a protective factor against atopy but a risk factor for wheeze in high-risk children.