Cow's Milk Exposure and Asthma in a Newborn Cohort: Repeated Ascertainment Indicates Reverse Causation

The effect of cow's milk consumption on childhood asthma has been debated for several years. This study attempts to provide further insight into this association through the use of a longitudinal study design. Newborns from parents with atopic history were recruited from Germany, Austria, and England (n = 696). For five repeated ascertainments, information was collected on cow's milk exposure, incidence of doctor-diagnosed asthma, and confounders. Generalized estimation equations, incorporating different models (concurrent, delayed, combined, and reverse causation), were used to determine this association. No association between cow's milk consumption and childhood asthma was found for the concurrent effects model (OR = 0.81, 95% confidence interval [CI]: 0.55, 1.20). In the delayed effects model, the direction of the association varied with time of follow-up. Thus, we stratified by period, which resulted in a significant protective delayed effect at 36 months (OR = 0.18, 95% CI = 0.06, 0.49). However, reverse causation negated this finding since the presence of asthma in prior months led to a reduction in further exposure to cow's milk (OR = 0.40, 95% CI = 0.16, 0.99). Hence, cow's milk consumption does not protect against childhood asthma. The apparent protection of cow's milk against asthma may result from parents of asthmatic children avoiding cow's milk, rather than actual prophylaxis.     

Cow's milk protein allergy: An entity for recognition in developing countries

Aim:  The aim of this prospective study was to determine cow's milk protein allergy (CMPA) cases in a tertiary care hospital in India and to study its clinical presentations and outcome following treatment.
Methods:  Consecutive children with chronic diarrhea from June 2004 to December 2007 were evaluated with hemogram, anti-endomysial antibody, upper gastrointestinal endoscopy, sigmoidoscopy and intestinal biopsies. Initial diagnosis of CMPA was based on characteristic intestinal biopsy (> 6 eosinophils/HPF) and diagnosis was confirmed by positive milk challenge.
Results:  Forty CMPA cases (25 boys, with a mean age of 17.2 ± 7.8 months and symptom duration of 8.3 ± 6.2 months) presented with diarrhea (bloody in 16, watery in 16, combined in three, recurrent hematemesis in two, rectal bleeding in one and one case each with pain in the abdomen with vomiting and anemia with occult bleeding). Sigmoidoscopy revealed aphthous ulcers in 82% of cases and rectal biopsy was positive in 97% of cases. All children improved on a milk-free diet. Milk challenge was positive in 100% of cases when it was done early (within 6 months). On follow up of 15 ± 9 months, milk was successfully restarted in 25 cases after a median milk-free period of 15 months, 10 were still on a milk-free diet and five were lost to follow up while on a milk-free diet.
Conclusions:  CMPA is not uncommon in a developing country such as India. Presence of aphthous ulcers and abnormal rectal biopsy are clues to initial diagnosis. Milk challenge confirms the diagnosis in all if it is done on time.     

The Relationship Between Cow's Milk Exposure and Type 1 Diabetes

Environmental factors are important for the development of Type 1 diabetes mellitus. They likely account for changes in the incidence of this disease over time, as well as the well-documented differences in incidence in ethnically and genetically similar people living in different parts of the world. There is a relationship between early cow's milk exposure and the development of Type 1 diabetes in humans, and between early cow's milk exposure and the development of autoimmune diabetes in rodent models of Type 1 diabetes. Moreover, some immunological studies have suggested a possible mechanism whereby exposure to cow's milk protein could result in β-cell directed autoimmunity and subsequent Type 1 diabetes. Although provocative, the existence of alternative explanations for these epidemiological and biological observations, suggest that the data are insufficient to conclude that the observed associations represent causal relationships or to mandate changes in recommendations for infant feeding. The question of whether or not avoidance of cow's milk protein in infancy will prevent Type 1 diabetes can, however, be tested in an international randomized clinical trial of infant diets, which is currently under review.     

北京、重庆、广州三城市儿童哮喘患病情况调查

目的分析北京、重庆、广州三城市儿童哮喘患病情况,为今后儿童哮喘防治工作提供科学依据。方法采用多阶抽样方法分别从北京、重庆、广州抽取0～14岁儿童10372、9846及4072名,采用国际通用的儿童哮喘及变态反应性疾病国际研究(International Study of Asthma and Allergies in Childhood,ISAAC)调查问卷进行调查,了解三城市儿童哮喘患病情况。结果北京、重庆、广州儿童哮喘患病率分别为3.15%、7.45%及2.09%,3岁以前首次发作的患儿比例分别为57.21%、69.91%及60.00%;北京、重庆、广州哮喘儿童中半数以上近12个月仍有喘息、夜间干咳、运动后干咳等哮喘症状。结论我国儿童哮喘患病仍呈明显上升趋势,大部分哮喘患儿3岁前发病。     

Asthma Mortality in Southern Brazil: Is There a Changing Trend?

Background. Mortality from asthma increased during the last decades but is now declining in some countries. Little is known about this trend in Brazil.    Objective. The objective of the study was to determine the trends in asthma mortality in Southern Brazil.    Methods. We reviewed death certificates of 566 people in the state of Rio Grande do Sul, Brazil, between 5 and 39 years of age in whom asthma was reported to be the underlying cause of death during the period of 1981-2003. Population data were available in 5-year age groups. Mortality rates were submitted to linear and quadratic regression procedures.    Results. Among children and teenagers (5-19 years), there were 170 asthma deaths, ranging from 4 to 13 deaths each year with rates of 0.154/100,000 to 0.481/100,000. In young adults (20-39 years), 396 asthma deaths occurred, ranging from 9 to 32 each year, with rates from 0.276/100,000 to 1.034/100,000. There was an initial increase in rates, with later stabilization, and then the start of a decline beginning in the late 1990s and the early part of this decade. This trend occurred in both age subgroups examined but was more evident in males.    Conclusions. Asthma mortality in southern Brazil remains low and appears to be decreasing after reaching a peak in the mid-1990s. The reason for these trends remains unknown.     

Endotoxin Exposure and Childhood Wheeze and Asthma: A Meta-Analysis of Observational Studies

Background. Exposure to endotoxin has been widely investigated as a potential factor for asthma and associated symptoms in children with different results. To clarify a potential relationship, we performed the present meta-analysis to integrate the results of studies examining the association of endotoxin exposure with wheeze and asthma in children. Methods. A search for relevant studies and reviews was conducted in MEDLINE, Highwire, CINAHL, and The Cochrane Library databases. Adjusted odds ratio (OR) with corresponding 95% confidence interval (CI) for endotoxin exposure and wheeze or asthma were retrieved and pooled to generate summary effect estimates in STATA 11.1. Results. Nineteen studies were included in the meta-analysis. The summary estimates suggested that endotoxin was positively associated with wheeze in infants and toddlers (meta-OR: 1.48, 95% CI: 1.10–1.98), but negatively related to asthma in school-aged children (meta-OR: 0.82, 95% CI: 0.69–0.97 for endotoxin concentration and 0.68, 95% CI: 0.50–0.93 for endotoxin load). Conclusions. Based on the studies evaluated, endotoxin is a risk factor for wheeze in younger children, but a protective factor for asthma in older children. Thus, this study supports the “hygiene hypothesis.”     

The Burden of Illness Experienced by Young Children Associated with Asthma: A Population-Based Cohort Study

Using Ontario healthcare administrative databases, over 228,000 children aged 0 to 9 years were identified as having asthma between 1994 and 1998 and followed until they turned 10 years old or the end of the study. The prevalence of childhood asthma increased by 35% during the study period. These children had a higher healthcare utilization and cost over $100 more per child per year than the general population, and contributed to over one third of the total Ontario Health Insurance Plan expenditures. Findings of this study revealed an enormous burden of illness to children with asthma and the healthcare system.     

Exposure to Indoor Biomass Fuel Pollutants and Asthma Prevalence in Southeastern Kentucky: Results From the Burden of Lung Disease (BOLD) Study

Background. Asthma is a chronic inflammatory respiratory disease, characterized by episodic and reversible airflow obstruction and airway hyperresponsiveness and is influenced by both genetic and environmental factors. Methods. The Burden of Obstructive Lung Disease (BOLD) survey was used to determine the prevalence of self-reported asthma in a target population of 325,000 adults aged ≥40 in Southeastern Kentucky. Postbronchodilator spirometry was used to classify subjects based on lung function. Risk factors for asthma in this population, in particular indoor usage of biomass fuels, were evaluated. Results. The overall study population was comprised of 508 individuals, with 15.5% reporting current asthma and 5.8% reporting former asthma. In this population, the following risk factors for asthma were identified: female sex, smoking, less than a high school education, increasing body mass index (BMI), and a history of cooking indoors with coal and wood. Cooking indoors with wood and coal for more than 6 months of one's life was shown to significantly increase the odds of reporting current asthma (odds ratio (OR) = 2.3, confidence interval (CI) 1.1, 5.0), whereas no effect was seen from a history of heating indoors with wood and coal (OR = 0.8, CI 0.4, 1.8). Conclusions. Current or former asthma was reported by 21.3% of the adult population. A history of using biomass fuels when cooking indoors significantly increased the risk of reporting current asthma in this population.     

Regional Variation in Asthma Symptom Prevalence in Latin American Children

Objectives. This study investigates the distribution pattern of asthma symptom prevalence in Latin American children aged 13–14 years. Methods. A randomized, cross-sectional and multicentric study on the prevalence and severity of asthma symptoms (lifetime asthma, current wheezing, and frequent sleep disturbance by wheezing) was conducted in 165,917 schoolchildren from 56 centers in 17 Latin American countries, as part of the International Study of Asthma and Allergies in Childhood (ISAAC), Phase Three. Results. The prevalence of lifetime asthma prevalence ranged from 1.2% to 33.1%, whereas current wheezing went from 3.9% to 30.8% and frequent sleep disturbance from 0.6% to 6.1%. An important proportion of centers (55%) reported a prevalence of asthma symptoms over 15%. There was no significant correlation between asthma symptom prevalence and latitude, altitude, or tropical setting. At country level, the prevalence of asthma was not associated with gross national income (GNI), proportion of population under the poverty line, or ancestry. Conclusions. This study suggests that ecological interactions, probably typical for each locality, may be the main determinants for the large variability of asthma prevalence in Latin America. The high prevalence of asthma symptoms found in children living in areas with low socioeconomic development would challenge the protective role against asthma of factors related to low hygiene and poverty; contrarily, in this region they would act as risk factors.     

Work-Related Stress and Asthma: Results from a Workforce Survey in New Zealand

Objective. We assessed the association between work-related stress and asthma in a cross-sectional workforce survey in New Zealand. Methods. Men and women randomly selected from the Electoral Roll were invited to take part in a telephonic interview, which collected information on current workplace exposures and respiratory symptoms. Participants rated how stressful they found their current job on a five-point scale. We conducted unconditional logistic regression to calculate prevalence odds ratios (OR) and 95% confidence intervals (CI) for job stress and both current and adult-onset asthma, adjusting for age, sex, smoking, and deprivation. Analyses were also stratified by sex, smoking status, body mass index, and age group. Results. Results were based on 2903 interviews. Participants with very or extremely stressful jobs were twice as likely to have current asthma (OR = 1.98; 95% CI = 1.52–2.58) and 50% more likely to have adult-onset asthma (OR = 1.50; 95% CI = 1.05–2.15) compared to those with not at all or mildly stressful jobs. This association was evident for both sexes and was not explained by either occupation, age, body mass index, or smoking, although the results did differ by smoking status. Conclusion. Our study adds to the sparse evidence on the relationship between work-related stress and asthma in adult working populations.     

Asthma Control: Do Patients' and Physicians' Opinions Fit in with Patients' Asthma Control Status?

The aim of this study was to determine the level of asthma control and the concordance between physicians' and patients' opinions and the real patients' situation. A total of 777 subjects (55% female) with asthma were recruited. The study comprised a 4-week follow-up period, during which subjects completed a diary recording peak expiratory flow (PEF), symptoms, and use of rescue medication. At the end, both physicians and patients rated asthma control status. The level of control was evaluated using a composite measure. Agreement among subjective assessments of asthma control by patients and physicians and objective evaluation with the composite measure was assessed through kappa scores. A total of 518 (67%) patients had “not well-controlled asthma,” being the remaining “totally controlled” (8%) or “well-controlled” (25%). “Not well-controlled asthma” was more frequent in smokers (82%) than in ex-smokers (70%) or in non-smokers (62%; p = 0.0002). Kappa scores between patients' and physicians' opinions and the real patients' status were 0.02 (95% CI, 0.01-0.05) and 0.07 (95% CI, 0.03-0.09), respectively. In conclusion, current level of asthma control is suboptimal for a majority (67%) of patients in Spain. Besides, asthma control is worse in smokers. Neither patients' nor physicians' opinions agree with patients' real situation. Both patients and physicians accept as normal a suboptimal status of their disease.     

Hospitalizations for Asthma in Children Are Linked to Undertreatment and Insufficient Asthma Education

Background. Most hospital admissions for asthma exacerbation are avoidable with adequate disease management. Objectives. The objective of this study was to describe the characteristics of children hospitalized with an asthma exacerbation to identify modifiable factors leading to hospitalization. Methods. The study was conducted in 14 pediatric units and included children 3–17 years of age who were hospitalized for an asthma exacerbation. The present analysis covers 498 children with known asthma. Staff physicians used a standardized questionnaire to collect data. Asthma history came from a parental interview and included usual asthma care, frequency of symptoms and quick-relief medication use in the previous month, frequency of exacerbations and number of unscheduled healthcare visits during the past year, and prior asthma-related hospitalizations. Results. More than half the children had previously been hospitalized for an exacerbation, 42% used continuous inhaled corticosteroids, and 57% had a regular follow-up for asthma. Asthma had been well controlled over the past year for 11%, 12% had experienced exacerbations during the past year but that had been optimally controlled during the previous month, and 11% had recently become poorly controlled (infrequent exacerbations in the previous year and non-optimal control in the previous month). The remaining 327 children (66%) were consistently poorly controlled (non-optimal asthma control in the previous month and frequent exacerbations over the previous year). Among this group, 69% had at least one of the following preventable risk factors for hospitalization: no regular controller therapy (49%), no asthma action plan (40%), or no follow-up for asthma (35%). Conclusions. Two-thirds of the children with asthma hospitalized for an exacerbation had been consistently poorly controlled during the previous year. They were frequently undertreated and insufficiently educated about asthma. Further efforts are needed to improve asthma treatment and education in France.     

Is the Prevalence of Asthma and Related Symptoms Among Brazilian Children Related to Socioeconomic Status?

Objective. To evaluate the relationship between socioeconomic status (SES) and the prevalence of asthma and related symptoms among Brazilian children. Methods. The International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire was applied to 23,457 six- to seven- year-old schoolchildren (SC) and 58,144 thirteen- to fourteen-year-old adolescents (AD) from 20 Brazilian cities. SES was evaluated by infant mortality index, poverty index, and average nominal income for people older than 10 years of age. Results. Current asthma ranged from 16.5% to 31.2% among SC and from 11.8% to 30.5% among AD and severe asthma from 2.9% to 8.5% (SC) and 2.6% to 9.1% (AD). Higher values were observed in Brazilian-Northern, -Northeastern and -Southeastern centers. No significant association between SES and prevalence of asthma and related symptoms was observed. Conclusions. In Brazil, the prevalence of asthma and related symptoms is quite variable and independent of SES.     

Rural Children with Asthma: Impact of a Parent and Child Asthma Education Program

The goal of this study was to determine the effectiveness of an asthma educational intervention in improving asthma knowledge, self-efficacy, and quality of life in rural families. Children 6 to 12 years of age (62% male, 56% white, and 22% Medicaid) with persistent asthma (61%) were recruited from rural elementary schools and randomized into the control standard asthma education (CON) group or an interactive educational intervention (INT) group geared toward rural families.

Parent/caregiver and child asthma knowledge, self-efficacy, and quality of life were assessed at baseline and at 10 months post enrollment. Despite high frequency of symptom reports, only 18% children reported an emergency department visit in the prior 6 months. Significant improvement in asthma knowledge was noted for INT parents and young INT children at follow-up (Parent: CON = 16.3; INT = 17.5, p < 0.001; Young children: CON = 10.8, INT = 12.45, p < 0.001). Child self-efficacy significantly increased in the INT group at follow-up; however, there was no significant difference in parent self-efficacy or parent and child quality of life at follow-up. Asthma symptom reports were significantly lower for the INT group at follow-up. For young rural children, an interactive asthma education intervention was associated with increased asthma knowledge and self-efficacy, decreased symptom reports, but not increased quality of life.     

Asthma as a Predictor of Obstructive Sleep Apnea in Urban African-American Children

Background. Asthma is a known co-morbid factor in childhood obstructive sleep apnea (OSA); however, little is known about the effects that asthma might have on the severity of OSA. We hypothesize that children with concomitant asthma and OSA have more severe OSA. Methods. We conducted a prospective study of 50 children with OSA diagnosed by polysomnography referred for tonsillectomy and adenoidectomy (T&A). The presence of concomitant asthma was determined by ISAAC questionnaire and spirometry. Atopy to common allergens was determined by skin prick testing. Due to the relatively small sample size, we limited hypothesis testing to cross tabulations with Fisher's Exact Test and t testing. We also employed a parsimonious ordinary least squares (OLS) regression assuming a large effect size. Results. Subjects (n = 50) included 32 males and 41 African-Americans. Age at T&A was 9.3 ± 3.4 years (mean ± S.D). Thirty-two subjects reported a history of asthma during their lifetimes, but the ISAAC questionnaire detected only 30 subjects. Twenty-two subjects reported current asthma. Atopy was found in 27 subjects. Apnea-hypopnea index (AHI) was lower in the current asthma group than in the lifetime asthma group but did not reach statistical significance. However, AHI was significantly higher in subjects with poorly controlled asthma. Further, in a parsimonious OLS model controlling for sleep efficiency and age, a history of lifetime asthma increased the AHI by 8.8 (p < 0.05). Discussion. In urban African-American children referred for T&A to treat OSA, a history of poorly controlled asthma is associated with more severe OSA.     

Prevalence of Asthma and Allergic Rhinitis Among School Children of Karachi,Pakistan, 2007

In recent times, the incidence of allergic diseases, particularly bronchial asthma, has been increasing worldwide. However, there appears to be no published data on the prevalence of allergic diseases among school children (3 to 16 years of age) in Karachi, Pakistan, with only limited data available among few age groups under one ISAAC study. The objective of this project was to investigate the prevalence of allergic diseases among school children (3 to 16 years of age) in the city of Karachi. The questionnaire that was used for data collection had previously been used for a similar study in neighboring Saudi Arabia and the U.A.E. In 2007, a total of 3,000 surveys were distributed in various schools of Karachi, of which 2,325 completed surveys were obtained. SPSS was used to perform statistical analysis on the collected data. Survey results showed that the frequency of diagnosed (previously seen by physicians) cases of asthma stood at 15.8%, while the frequency of allergic rhinitis was found to be 28.50% among these children. Other parameters that were analyzed included dry cough (20.1%), wheezing (11.7%), breathlessness (15.40%), and eczema (21.8%). Furthermore, smoking by family members was found to be associated with asthma (p value less than 0.05), allergic rhinitis (p value less than 0.05), breathlessness (p value less than 0.05), dry cough (p value 0.002), and wheezing (p value less than 0.05). This study reveals that there is a significant number of school children in the metropolitan city of Karachi who have various allergic symptoms. It also sheds light on the fact that exposure to indoor environmental factors as well as family atopy can play a key role in increasing the chances of an individual to experience asthma and other allergy symptoms.     

Asthma and Major Depressive Episode in Adolescents in France

Rationale. The association between asthma and anxiety disorders in teenagers is well documented, but data about the association with mood disorders are scarce. Methods. We analyzed data from a cross-sectional study conducted among ninth grade schoolchildren in France in 2003–2004. The teenagers were selected by two-stage sampling and interviewed by school doctors/nurses using a standardized questionnaire including questions about asthma and asthma-like symptoms. They also completed a self-administered questionnaire in which the occurrence of major depressive episodes (MDEs) during the past 12 months was assessed by the Composite International Diagnostic Interview—Short Form. Results. A total of 7000 teenagers (mean age 15.1 years) were included. The prevalence of wheezing in the past 12 months was 10.0% and that of current asthma (wheezing in the past 12 months in children who had already had asthma attacks, or treatment for wheezing or asthma in the past 12 months) was 8.5%. The prevalence of MDE during the past year was 14.2% in teenagers with current asthma versus 9.2% among the others. The association between current asthma and past-year MDE remained significant after adjustment for age, gender, family structure, and the father’s employment status. Asthma was uncontrolled (at least four attacks of wheezing, one awakening per week due to wheezing, one severe wheezing, four unplanned medical visits, or one hospitalization for a wheezing attack in the past year) in more than half (58.3%) of asthmatic teenagers with an MDE in the past year versus 35.3% of those without an MDE. Conclusion. Asthma is associated with a higher prevalence of MDE. Among adolescents with asthma, MDE is associated with poorer asthma control. These findings highlight the need for a comprehensive care management of asthma in France that takes the psychological dimension into account.