Incidence Of Childhood Asthma Research Articles

Immune-mediated disease pathogenesis in respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is an important cause of severe respiratory disease in persons at both extremes of age. Wheezing is a cardinal sign of infection and the illness is associated with an increased incidence of childhood asthma. Data from both humans and animal models have linked severe disease in infants and the syndrome of vaccine-enhanced illness with an aberrant composition of CD4+ T cells, suggestive of an exaggerated Th2 response. Studies in murine models have shown that prior vaccination, coexisting allergic inflammation, or direct modulation of the cytokine milieu can profoundly influence the immune response to RSV and thereby affect the expression of disease. In addition, there are intrinsic antigenic properties of the RSV G glycoprotein that promote Th2 responses and eosinophilia. This paper proposes an integrated working model of how host and virus factors interact to determine the characteristics of RSV-induced illness. This model suggests strategies for the development of new vaccine and immunotherapeutic interventions, and creates a framework for asking additional questions about the immunopathogenesis of RSV.

A comparison of active and simulated chiropractic manipulation as adjunctive treatment for childhood asthma: Balon J, Aker PD, Crowther ER, Danielson C, Cox PG, O'Shaughnessy D, Walker C, Goldsmith CH, Duku E, Sears MR. New England Journal of Medicine 1998; 339: 1013–1020.

The Childhood Asthma Prevention Study is a randomized controlled trial to measure whether the incidence of atopy and asthma can be reduced by house dust mite allergen reduction, a diet supplemented with omega-3 fatty acids, or a combination of both interventions. Six hundred and sixteen pregnant women whose unborn children were at high risk of developing asthma because of a family history were randomized prenatally. Study groups are as follows: Group A (placebo diet intervention, no house dust mite reduction), Group B (placebo diet intervention, active house dust mite reduction), Group C (active diet intervention, no house dust mite reduction), and Group D (active diet intervention, active house dust mite reduction). The house dust mite reduction intervention comprises use of physical and chemical methods to reduce allergen contact. The dietary intervention comprises use of a daily oil supplement from 6 months or at onset of bottle-feeding, and use of margarine and cooking oils based on sunflower or canola oils to increase omega-3 dietary intake. Data is collected quarterly until the infant is 1 year old and then half yearly until age 5 years. Questionnaires are used to collect respiratory illness history and information about diet and home environment. Dust is collected from the child's bed and bedroom and playroom floors. Blinded assessments are conducted at 18 months, 3 years, and 5 years. Skin prick tests to common allergens, blood tests, and detailed illness, medication use, and vaccination histories are collected. Primary outcomes will be the development of allergic sensitization and the presence and severity of asthma. This study is designed to measure the effectiveness of allergen reduction and dietary supplementation, both separately and in combination, for the primary prevention of atopy and asthma. The results of this study may have important implications for public health policies to reduce the incidence of childhood asthma. Control Clin Trials 2001;22:333–354

Maternal smoking and childhood asthma.

The role of maternal smoking as a causal factor for the incidence of childhood asthma is still not clearly established. It was investigated among 3- and 4-year-old-child incident cases confirmed by a 6-year follow-up (n = 294) and cases who no longer had symptoms after diagnosis (n = 110). The study took place in Montréal, Canada, between 1988 and 1997. Persistent and transient cases were compared with their respective controls from the original case-control study of incidence. The odds ratio for heavy maternal smoking adjusted for known risk factors for asthma was 3.84 (95% confidence interval: 1.68, 8.76) among persistent cases and close to one among transient cases.

Indoor mold and Children's health

Reactive airways disease in children is increasing in many countries around the world. The clinical diagnosis of asthma or reactive airways disease includes a variable airflow and an increased sensitivity in the airways. This condition can develop after an augmented reaction to a specific agent (allergen) and may cause a life-threatening situation within a very short period of exposure. It can also develop after a long-term exposure to irritating agents that cause an inflammation in the airways in the absence of an allergen. (paragraph) Several environmental agents have been shown to be associated with the increased incidence of childhood asthma. They include allergens, cat dander, outdoor as well as indoor air pollution, cooking fumes, and infections. There is, however, increasing evidence that mold growth indoors in damp buildings is an important risk factor. About 30 investigations from various countries around the world have demonstrated a close relationship between living in damp homes or homes with mold growth, and the extent of adverse respiratory symptoms in children. Some studies show a relation between dampness/mold and objective measures of lung function. Apart from airways symptoms, some studies demonstrate the presence of general symptoms that include fatigue and headache and symptoms from the central nervous system. At excessive exposures, an increased risk for hemorraghic pneumonia and death among infants has been reported. (paragraph) The described effects may have important consequences for children in the early years of life. A child's immune system is developing from birth to adolescence and requires a natural, physiologic stimulation with antigens as well as inflammatory agents. Any disturbances of this normal maturing process will increase the risk for abnormal reactions to inhaled antigens and inflammagenic agents in the environment. (paragraph) The knowledge about health risks due to mold exposure is not widespread and health authorities in some countries may not be aware of the serious reactions mold exposure can provoke in some children. Individual physicians may have difficulty handling the patients because of the lack of recognition of the relationship between the often complex symptoms and the indoor environment (paragraph) The workshop was organized to develop a basis for risk assessment and formulation of recommendations, particularly for diagnostic purposes and prevention, and to formulate priorities for future research. The participants were all active researchers with current experience in child health, molds, and respiratory disease. They were engaged in free and intensive discussions on a scientific basis throughout the duration of the 3-day workshop (paragraph) This monograph contains peer-reviewed papers based on individual presentations at the workshop as well as the workshop conclusions. They are offered to the public health community, administrators, research agencies, physicians, particularly pediatricians, nurses and health workers as information and encouragement to engage themselves in this health problem of importance for the next generation in our population. (paragraph) Acknowledgments: The workshop received financial support from the U.S. Environmental Protection Agency, the National Center for Environmental Assessment at the U.S. EPA, the Vardal Foundation (Sweden), Astra Corp (Sweden), the Committee on Organic Dusts, International Commission on Occupational Health. The printing of this document was made possible by a grant from the Center for Indoor Air Research (U.S.). Yvonne Peterson, research secretary, provided excellent and invaluable assistance in the organization and publication efforts.

Determination of the incidence of bronchial asthma in children of school age

A group of children aged 7 and 1314 was chosen using the questionnaire data of 6104 pupils in Nalchik according to the International program ISAAC. It is possible to identify the patients which need the diagnosis refinement by studying medical documentation in the risk group.

Original Paper: Cumulative incidence of asthma diagnosis at the age of seven in a birth cohort

Objectives: The aim of this study was to follow a cohort of children in a defined region from birth up to the age of seven for the occurrence of a doctor's diagnosis of asthma in the medical records in primary healthcare and hospital.Methods: In a defined region in Sweden with a population of about 150,000 inhabitants, all children (n=2104) born in the University Hospital in 1990 were recorded. Seven years later, 82% (n=1752) were still living in the region; their medical files at the Department of Paediatrics and all primary healthcare centres in the region were checked for an asthma diagnosis (ICD 9).Results: The results gave a total cumulative asthma incidence of 10.9% among seven-year-old children in the studied region. A significantly (p<0.01) higher number of boys (13.1%) than girls (8.5%) had this diagnosis. The incidence of asthma was highest (p<0.005) among boys living in urban areas at the age of seven. Increased relative risks for asthma were also found among children born in the autumn (p<0.05) and children born of young mothers (p<0.0001).Conclusions: These results indicate a higher childhood asthma incidence than previously presented figures for Sweden and illustrate the importance of collaboration between general practitioners in primary healthcare and paediatricians in hospitals in order to cope with the disease in diagnostic, curative and preventive respects.

Evolution of asthma through childhood.

The greatest incidence of childhood asthma is among males under 5 years, with decreasing numbers of new cases with age. Many young children wheeze, but remission is common especially in non-atopic children without a family history of allergy or asthma, whose wheezing relates more to infections and environmental tobacco smoke exposure. The prognosis of childhood asthma is best established from population studies, in which some two-thirds of wheezy children become symptom-free as adults, whereas follow-up studies of wheezing children seen in office or specialty clinic practice, who generally have more severe asthma, show a much greater likelihood (60-80%) of persistence of asthma into adulthood. Factors predisposing to persistence of childhood asthma include a positive family history, development of atopy, environmental exposures to allergens and cigarette smoke, markers of severity of childhood asthma, and female gender.

Outdoor Environmental Injury of the Airways and Development of Allergic Respiratory Diseases

Asthma affects more than 17 million people in the United States;1/3 of these are children. Children are particularly vulnerable to airborne pollution because of their narrower airways and because they generally breathe more air per pound of body weight than adults, increasing their exposure to air pollutants. However, the results from previous studies on the association between motor vehicle emissions and the development of childhood wheeze and asthma are conflicting. Therefore, we conducted a meta-analysis to clarify their potential relationship.MEDLINE, Highwire, and The Cochrane Library databases were searched for relevant studies. Adjusted odds ratio (OR) with corresponding 95% confidence interval (CI) for the association between traffic air pollutants and wheeze or asthma were retrieved from individual studies and pooled to generate summary effect estimates (meta-OR) in STATA 11.1.Nineteen studies were included in the meta-analysis. Exposure to nitrogen dioxide (meta-OR: 1.05, 95% CI: 1.00–1.11), nitrous oxide (meta-OR: 1.02, 95% CI: 1.00–1.04), and carbon monoxide (meta-OR: 1.06, 95% CI: 1.01–1.12) were positively associated with a higher prevalence of childhood asthma. Exposure to sulfur dioxide (meta-OR: 1.04, 95% CI: 1.01–1.07) was positively associated with a higher prevalence of wheeze in children. Exposure to nitrogen dioxide was positively associated with a higher incidence of childhood asthma (meta-OR: 1.14, 95% CI: 1.06–1.24), and exposures to particulate matter was positively associated with a higher incidence of wheeze in children (meta-OR: 1.05, 95% CI: 1.04–1.07).Living or attending schools near high traffic density roads exposes children to higher levels of motor vehicle air pollutants, and increases the incidence and prevalence of childhood asthma and wheeze.

Management of acute asthma in children.

Aims and intended learning outcomes The aim of this article is to update the reader's knowledge of the management of acute exacerbations of childhood asthma. After reading this article you should be able to: ■ Recall the causes, incidence and treatment principles of childhood asthma ■ Recognise the signs of an acute asthmatic attack which indicate the need for referral to hospital ■ Describe the management of an acute asthmatic episode ■ Recognise the importance of consistent advice and good communication for the effective management of asthma in children.

Towards prevention

Towards prevention

REVIEW OF PRESCRIBED TREATMENT FOR CHILDREN WITH ASTHMA IN 1990

This large study suggests a high incidence of asthma in children, assuming the medications were appropriately prescribed. Published guidelines may have affected the increased use of inhaled corticosteroids.

Indoor air pollution and childhood asthma: effective environmental interventions.

Exposure to indoor air pollutants such as tobacco smoke and dust mites may exacerbate childhood asthma. Environmental interventions to reduce exposures to these pollutants can help prevent exacerbations of the disease. Among the most important interventions is the elimination of environmental tobacco smoke from the environments of children with asthma. However, the effectiveness of reducing asthmatic children's exposure to environmental tobacco smoke on the severity of their symptoms has not yet been systematically evaluated. Dust mite reduction is another helpful environmental intervention. This can be achieved by enclosing the child's mattresses, blankets, and pillows in zippered polyurethane-coated casings. Primary prevention of asthma is not as well understood. It is anticipated that efforts to reduce smoking during pregnancy could reduce the incidence of asthma in children. European studies have suggested that reducing exposure to food and house dust mite antigens during lactation and for the first 12 months of life diminishes the development of allergic disorders in infants with high total IgE in the cord blood and a family history of atopy. Many children with asthma and their families are not receiving adequate counseling about environmental interventions from health care providers or other sources.

Chest Pain in Otherwise Healthy Children and Adolescents Is Frequently Caused by Exercise-Induced Asthma

Chest pain in children and adolescents, unlike in adults, is rarely of cardiac origin and its etiology is frequently unknown. In this age group, chest pain can limit normal activity and sports participation. The reported incidence of exercise-induced asthma in children with chest pain is less than 20%. For this study, 88 otherwise healthy children and adolescents with chest pain followed a treadmill protocol without a warm-up period designed to obtain a target heart rate of 180 or greater during the first several minutes of exercise. Patients maintained this workload for 6 to 8 minutes. Pulmonary function tests performed prior to exercise and at 2, 5, 10, 15, 20, and 25 minutes revealed a decrease in forced expiratory volume in 1 second or peak expiratory flow rate of greater than or equal to 15% in 64 (72.7%) children. Inhaled albuterol resulted in subjective improvement in 97% (35/36) and objective improvement in 70% (25/36) of patients. In otherwise healthy children and adolescents with chest pain, the incidence of exercise-induced asthma seems greater than previously reported. Treatment with bronchodilators may help these patients lead a more active life-style.

Increased Incidence of Asthma in Children of Smoking Mothers

The relationship between parental smoking and both subsequent development of asthma and subsequent lung function (before age 12) was studied in more than 700 children enrolled before age 5. Children of mothers with 12 or fewer years of education and who smoked 10 or more cigarettes per day were 2.5 times more likely (95% confidence interval 1.42 to 4.59; P = .0018) to develop asthma and had 15.7% lower maximal midexpiratory flow (P less than .001) than children of mothers with the same education level who did not smoke or smoked fewer than 10 cigarettes per day. These relationships were independent of self-reported respiratory symptoms in parents. There was no association between maternal smoking and subsequent incidence of asthma or maximal midexpiratory flow among children of mothers with more than 12 years of education. It is concluded that children of lower socioeconomic status may be at considerable risk of developing asthma if their mothers smoke 10 or more cigarettes per day. It is speculated that recently reported increases in prevalence of childhood asthma may be in part related to the increased prevalence of smoking among less educated women.

Lower Airway Disorders

Purpose of Study The purpose of this study was to assess the relationship between transient tachypnea of the newborn and the incidence of childhood asthma. Study Population The study was done retrospectively. Transient tachypnea of the newborn was diagnosed in children whose gestational age was greater than 34 weeks if they developed a respiratory rate greater than 60/minute for at least 12 hours within 6 hours after birth. All patients had chest x-rays consistent with transient tachypnea of the newborn, and none of the children had hypercapnia or required assisted ventilation. Controls were selected who had the same birth rate and similar gestational age. Total of 58 children with transient tachypnea of the newborn were enrolled as well as 58 controls. Methods Children were examined at 4 to 5 years of age. They were examined in a blind fashion by two physicians. Data accumulated included a history of atopy in the child and in the family as well as pulmonary symptoms and use of bronchodilators. Findings Children who had transient tachypnea of the newborn had a greater incidence of wheezy breathlessness, childhood atopy, and family history of asthma. Reviewer's Comments In their discussion, the authors indicate that the β-adrenergic system plays a role in the absorption of fluid from the newborn's lung at birth. Impairment of the β-adrenergic system, if persistent, would predispose such children to have subsequent difficulty with asthma. This is consistent with the recent prospective study (N Engl J Med. 1988;319:1112-1117) which suggests that diminished lung function is a predisposing factor for the development of wheezing.

The natural history of asthma in childhood.

The incidence and prognosis of childhood asthma and wheezing illness (AW) was studied using data obtained at ages 7, 11, and 16 from a national cohort of 8806 children born in 1958. By the age of 16, 24.7% were reported to have experienced at least one episode of AW. In 18.3% AW had started before the age of 8, but only 4.2% continued to have symptoms in later childhood. A further 3.6% began to have AW between the ages of 8 and 11, and 2.8% began between the ages of 12 and 16. Of those with AW at age 7, 28.3% had symptoms at 11 and 16.5% at 16; these proportions were about doubled if AW at 7 had been severe. The associations between natural history and a large number of perinatal, social, environmental, and medical factors were examined. Those which predicted the onset of AW after the age of 7 were: male sex of child; mother aged 15-19 at child's birth; history of pneumonia, whooping cough, throat or ear infections or tonsillectomy; eczema, allergic rhinitis; and periodic vomiting or abdominal pain.

Incidence of exercise-induced asthma in children

The incidence of exercise-induced asthma (EIA) was studied in 134 asthmatic and 102 nonasthmatic atopic children and compared to that in 56 nonatopic children. Pulmonary function tests measuring forced vital capacity (FVC) and 1-sec forced expiratory volume (FEV 1) were performed on each child prior to and serially for 20 min following free running exercise. The incidences of EIA among the asthmatic and atopic nonasthmatic children were 63% and 41%, respectively. This phenomenon is widespread among allergic children and cannot be accurately predicted from the history. A simple and easily performed outpatient procedure is described for the diagnosis of EIA.

Incidence and etiology of asthma in childhood.

Incidence and etiology of asthma in childhood.

Development and course of asthma in children.

In outlining the development and course of asthma in children it is important to emphasize that, although asthma is a common illness, it is not a reportable one, and therefore its true incidence is unknown and can only be estimated indirectly. Our impressions of its frequency come from a variety of sources, none of which are comparable groups. These range from local surveys, army inductee examinations, hospital admissions, to sickness surveys of special groups. Dublin and Marks, 1 in summarizing all available statistics, in 1946, state that the incidence appears to be 0.5% for all ages for the entire country, or more than 500,000 persons excluding those who have recovered. Representative examples of these statistics are shown in Table 1. 1-6 Studies of the incidence of asthma in children and young people are even more meager than for adults. The sickness survey of Collins 5 for 18 states reports rates

Air-borne molds in Honolulu

1. 1. Mold spore counts in Honolulu are much lower than in most mainland cities. 2. 2. Hormodendrum comprises 33 per cent and Alternaria less than 1 per cent of the total count. 3. 3. The average monthly plate count does not seem to be correlated with the incidence of asthma in children. 4. 4. Spore counts tend to be higher on windy days than on calm days, in spite of the direction of the wind. 5. 5. A method of minimizing the effect of wind on spore counts by the use of an “air sampler,” as described by Alvarez, was found to be fairly satisfactory.