Pregnancy and birth outcomes in families with asthma.

Childhood Asthma Prevention Team.

Clinical Epidemiology Unit, The Children's Hospital, Westmead, New South Wales, Australia. seemam chw.edu.au

Studies of maternal asthma in pregnancy have shown an increased risk of adverse neonatal and maternal outcomes such as preeclampsia, hypertension, cesarean delivery, prematurity, low birth weight, and perinatal/neonatal mortality. However, results are not consistent between studies. We studied the association between maternal asthma and various adverse neonatal and maternal outcomes and explored whether there is any evidence that pregnancy exacerbates maternal asthma. The data were collected as part of the Childhood Asthma Prevention Study. Pregnant women with asthma or women whose partners or other children had current symptoms of asthma were recruited at six Sydney hospitals. All women recruited were post 36 weeks gestation and were living within 30 km of the study recruitment center. Information about family history of asthma was collected using a questionnaire at 36 weeks gestation and subsequent information about antenatal and perinatal events was obtained from hospital records. Data from 611 pregnant women were available for analysis, 340 of whom had asthma. Hypertension was significantly more common in asthmatics than in nonasthmatics [OR = 2.16 (1.02-4.6), p < 0.043]. The prevalence of gestational diabetes, labor complications, delivery complications, and adverse neonatal outcomes did not differ significantly between the groups. We also found that the course of maternal asthma usually remains unchanged during pregnancy, but that more severe asthma is likely to get worse. We have confirmed previous observations that women with asthma are at increased risk of hypertension in pregnancy, which is consistent with studies that show that pregnant asthmatic women have a slightly increased risk of preeclampsia. However, we did not find evidence of an increased risk of adverse perinatal outcomes.

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Prevalence and risk factors of asthma and wheezing among US adults: an analysis of the NHANES III data.

Whitehead LW.

The Texas Tech University Health Sciences Center, Department of Health Services Research and Management, Lubbock, TX 79430, USA. ahmed.arif ttmc.ttuhsc.edu

The prevalence of asthma has been on the increase in the USA and worldwide. To understand the worsening epidemiological trends of asthma, this study analysed the data from the third National Health and Nutrition Examination Survey (NHANES III) to determine the prevalence and risk factors for asthma and wheezing among US adults. This analysis used data from 18,825 US adults aged > or = 20 yrs who had participated in the NHANES III project. After excluding subjects with physician-diagnosed emphysema, a total of 18,393 subjects were included in the final analysis. The prevalence of current asthma (asthma) was 4.5% and the prevalence of wheezing in the previous 12 months (wheezing) was 16.4%. Mexican-Americans exhibited the lowest prevalence of asthma when compared with other race/ethnic groups. Multiple logistic regression analysis showed that Mexican-Americans were less likely to report asthma when compared to non-Hispanic whites. Low education level, female sex, current and past smoking status, pet ownership, lifetime diagnosis of physician-diagnosed hay fever and obesity were all significantly associated with asthma and/or wheezing. No significant effect of indoor air pollutants, as derived from the use of household heating/cooking appliances, on asthma and wheezing was observed in this study. In conclusion, this study observed racial/ethnic differences in the prevalence of asthma and wheezing and identified several important risk factors that may contribute to development and/or exacerbation of asthma and wheezing. Contrary to earlier reports, the proxy measures of indoor air pollution used in this study were not found to be associated with increased risk of asthma and wheezing.

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Asthma morbidity, control and treatment in New Zealand: results of the Patient Outcomes Management Survey (POMS), 2001.

POMS Steering Committee.

P3 Research, Wellington, New Zealand. shaun p3research.co.nz

AIMS: To determine the magnitude of morbidity from asthma within the New Zealand population, the degree of satisfaction of patients with their asthma control, and the level of asthma control achieved in relation to treatment. METHODS: Participants were randomly selected from 29 randomly chosen general practices throughout New Zealand. Information was collected from demographic and clinical questionnaires and from lung function tests. Criteria based on GINA guidelines were developed to define the level of asthma control for each participant, their opinion of their level of control, and to define which participants were under-treated. RESULTS: A total of 445 patients (327 adults, age 16-68; 118 children, age 7-15) took part in the study. Ninety three per cent of adults had asthma that was sub-optimally controlled, 71% had asthma that was not well controlled, and 19% had asthma that was markedly out of control. For children, these figures were 90%, 42% and 4% respectively. These results were consistent regardless of asthma severity. In adults and children whose asthma was not well controlled, 49% and 71% respectively were under-treated. For those whose asthma was markedly out of control, 89% and 75% of adults and children respectively were under-treated. CONCLUSIONS: A significant proportion of patients have asthma that is not well controlled or that is markedly out of control, and the majority are under-treated.

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Exercise-induced bronchospasm in children: comparison of FEV1 and FEF25-75% responses.

Martins MA.

Department of Medicine, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil.

The response of asthmatic children to exercise has usually been evaluated by forced expiratory volume in 1 sec (FEV(1)). We reasoned that other respiratory indexes derived from the forced vital capacity maneuver such as forced expiratory flow between 25-75% of vital capacity (FEF(25-75%)) would add significant information in the evaluation of the relationship between asthma severity and response to exercise. We studied 164 children with intermittent (n = 63), mild persistent (n = 30), moderate persistent (n = 40), and severe persistent asthma (n = 31). Subjects exercised for 6 min on a cycle ergometer at 80% of their maximum heart rate, and spirometry was performed before and 5, 10, and 20 min after exercise. There was good correlation between changes in FEV(1) and FEF(25-75%) after exercise (r = 0.60, P < 0.001 for intermittent asthma and r = 0.80, P < 0.001 for severe persistent asthma). The presence of a fall in both FEV(1) (>/=10%) and in FEF(25-75%) (>/=26%) when compared to a decrease in only one of these two indexes was significantly greater in children with more severe asthma (60.0% for intermittent asthma and 94.4% for severe persistent asthma, P = 0.022). FEF(25-75%) can decrease in response to exercise without changes in FEV(1), mainly in children with mild asthma. In the evaluation of the response to exercise in children with different asthma severities, more than one maximum expiratory flow-volume parameter should be used. Copyright 2003 Wiley-Liss, Inc.

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What can we learn about asthma from studying occupational asthma?

Frew AJ.

Department of Allergy and Respiratory Medicine, School of Medicine, University of Southampton, Southampton, England, UK. L.A.Morris soton.ac.uk

OBJECTIVE: To review the clinical features and underlying mechanisms of occupational asthma in an attempt to glean insights into various other forms of asthma. DATA SOURCES: Published literature, including consensus guidelines on diagnosis and management of occupational asthma. STUDY SELECTION: This article represents a synthesis of these data sources and the opinion of the author. RESULTS: Occupational asthma may be caused by a variety of mechanisms, including both IgE-dependent and non-IgE-dependent immunological processes. IgE-dependent mechanisms are responsible for reactions to all high-molecular-weight occupational antigens and to some but not all low-molecular-weight antigens. Factors in sensitization and onset include the general genetic predisposition to make IgE and the specific responsiveness of the individual to particular allergens. Once sensitized, the main factor that influences the onset of symptoms is the degree of exposure. In general, the higher the level of exposure, the more likely the sensitized person is to develop asthma. CONCLUSIONS: Occupational asthma can be induced by a variety of agents that appear to use different mechanisms to affect the airway. Studies of the remission of occupational asthma indicate that resolution is a slow process. However, the study of occupational asthma may eventually allow us to identify treatments that will accelerate remission or induce remission in other forms of asthma.

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Results of an inner-city school-based asthma and allergy screening pilot study: a combined approach using written questionnaires and step testing.

Luckett P.

Department of Internal Medicine, Division of Allergy and Immunology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8859, USA. rebecca.gruchalla utsouthwestern.edu

BACKGROUND: A questionnaire alone may not be an adequate screening tool for asthma. OBJECTIVE: To determine whether an asthma questionnaire used in combination with an exercise step test is better than a questionnaire alone in screening for asthma in children and to evaluate the validity of a rhinitis questionnaire in determining atopy. METHODS: The International Study of Asthma and Allergies in Childhood (ISAAC) asthma core questionnaire was used to screen for asthma in 307 inner-city first through third graders. All children who had scores consistent with a diagnosis of asthma underwent step testing, as did a subset of children who had negative overall scores. All children who had inconsistent asthma scores and step test results underwent methacholine challenge testing. The same 307 children underwent rhinitis screening and children who had one or more positive responses on the ISAAC rhinitis questionnaire underwent skin testing as did a subset of children who had all negative responses. RESULTS: Three hundred of 307 asthma and rhinitis questionnaires were returned. Twenty-eight children (9%) had global asthma scores that were considered to be positive (5 or above). Twenty-four of these children underwent step testing as did 34 randomly selected children who had negative global asthma scores. Thirty-one (91%) of the 34 children who had negative global asthma scores had negative step tests. Similarly, 20 of 24 children (83%) of the children who had positive global asthma scores had negative step tests. Only 4 children who had positive global asthma scores were step test-positive or had reversible airway obstruction at baseline. Using a positive methacholine challenge as the gold standard for establishing bronchial hyperresponsiveness, the global asthma score derived from the eight-item ISAAC asthma questionnaire yielded a sensitivity of 64%, a specificity of 11%, a positive predictive value of 47%, and a negative predictive value of 20%. Comparing the six-item ISAAC rhinitis questionnaire results to the gold standard, skin test reactivity, the questionnaire yielded a sensitivity of 76%, a specificity of 21%, a positive predictive value of 56%, and a negative predictive value of 40%. CONCLUSIONS: Step testing was not useful as a screening tool for asthma. In addition, the ISAAC asthma questionnaire may not be a good asthma screening tool for inner-city pediatric populations, especially if the form is self-administered. Investigators should first validate both the ISAAC asthma and rhinitis screening questionnaires in the particular population to be studied before widespread asthma and allergy screening efforts are initiated using these tools.

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Outcome results of a school-based screening program for undertreated asthma.

Kurland M.

Department of Research, Olmsted Medical Center, Rochester, Minnesota 55904, USA. yawnX002 tc.umn.edu

BACKGROUND: Undertreatment of asthma is associated with significant potentially preventable morbidity, including frequent school absences. Guideline dissemination and clinician education have met with variable success. School-based identification of children with potentially undertreated asthma may provide an alternative strategy for improving asthma management in children. OBJECTIVE: To evaluate the effectiveness of school-based identification of potentially undertreated asthma. METHODS: A controlled trial of school-based identification of children with known but symptomatic asthma using mailed parent surveys, letters recommending medical follow-up, and medical record review to evaluate changes in asthma treatment after referral. RESULTS: Most parents (79.9%, n = 5,116 respondents) responded to the survey and 19.4% (n = 994) of children were reported to have a physician diagnosis of asthma or reactive airway disease. Letters of referral were sent to 489 children with parent-reported asthma who were identified as having potentially undertreated asthma. Approximately one-third (31.2%, n = 153) of these children had physician visits, and 92 (18.8% of all referred) had documented medication changes. In addition, there were 20 new physician diagnoses in this group of children. In the control group of 604 children with asthma, there were significantly fewer children with asthma-related visits (131, 21.7%, P = 0.0004) and children with medication changes (74, 12.3%, P = 0.002) in a comparable 6-month window. CONCLUSIONS: School-based screening or case identification increased the number of physician asthma-related visits and changes in asthma therapy.

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Left-handedness in asthmatic children.

Molyvdas PA.

Physiology Department, Medical School, University of Thessaly, Larissa, Greece.

Left-handedness has been associated with asthma and allergic disorders. The Geschwind-Behan-Galaburda (GBG) hypothesis could explain this association. In view of previous findings, we investigated the distribution of laterality scores among asthmatic children and controls aged 4-8 years old. Seventy families with asthmatic children were administered the International Study of Asthma and Allergy in Childhood (ISAAC) questionnaire and the Edinburgh Left-handedness Inventory. A sample of 70 families with non-asthmatic, healthy children was used as controls. The majority of children had mild asthma. Ambidexterity was the main feature in the asthmatic children. A statistically significant difference in the laterality quotient (LQ) distribution was found in the group of asthmatic children with allergic rhinitis (LQ mean value in the asthmatic children with allergic rhinitis: 42.85 vs. 79.50 in the rest of the asthmatic children). These results suggest that there is a tendency towards left-handedness in asthmatic children and lend support to the GBG hypothesis.

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