Defining cases of asthma, eczema and allergic rhinitis using electronic health records in the Born in Bradford birth cohort.

Key Messages • In electronic health records, the accuracy of diagnostic codes to define outcomes can be uncertain • The accuracy can vary in different settings, doctors and practices, even with validated codes • We recommend definitions combining codes previously described and other codes available in the records.

Evidence for causal associations between prenatal and postnatal antibiotic exposure and asthma in children, England.

BACKGROUND: Higher risks of asthma have been observed in children with prenatal exposure to antibiotics and during early life compared with those who have not. However, the causality of such associations is unclear. OBJECTIVE: To assess whether exposure to antibiotics in early life had a causal effect in increasing the risk of asthma in children diagnosed at 5-8 years of life, and the impact in the target population. METHODS: Data were from electronic health records and questionnaires for children and their mothers in the Born in Bradford birth cohort. Exposure variables were prescriptions of systemic antibiotics to the mother during pregnancy (prenatal) and to the children at 0-24 months of life (postnatal). We assessed the association in 12,476 children with several approaches to deal with different sources of bias (triangulation): the interactions with mother's ethnicity, mode of delivery, and between prenatal and postnatal exposures; dose-response; and estimated the population attributable risk. RESULTS: There was an association between prenatal exposure at 7-27 days before the child's birth and asthma (adjusted OR = 1.40; 1.05, 1.87), but no association with the negative control exposure (before pregnancy) (adjusted OR = 0.99 (0.88, 1.12)). For postnatal exposure, the adjusted OR was 2.00 (1.71, 2.34), and for sibling analysis, it was 1.99 (1.00, 3.93). For postnatal exposure, the risk of asthma increased with the number of prescriptions. The observed effect of both exposures was lower among children with mothers of Pakistani ethnicity, but inconclusive (p > .25). The interaction between prenatal and postnatal exposures was also inconclusive (p = .287). The population attributable risk of postnatal exposure for asthma was 4.6% (0.1% for prenatal). CONCLUSIONS: We conclude that the associations between both late-pregnancy prenatal exposure to antibiotics and postnatal exposure to antibiotics and an increased risk of asthma are plausible and consistent with a causal effect.

Asthma cases in childhood attributed to atopy in tropical area in Brazil.

OBJECTIVE: This study aimed to explore the association between asthma and atopy in a cohort of children living in a large urban center in Brazil. Atopy was defined by the presence of allergen-specific IgE in serum or by a positive skin prick test. METHODS: In a sample of 1 445 Brazilian children, the association between the prevalence of asthma, skin prick test positivity, and allergen-specific IgE in serum was investigated. RESULTS: The prevalence of asthma was 22.6%. The presence of serum allergen-specific IgE was frequent in asthmatics and nonasthmatics, and the prevalence of asthma increased only with levels of allergen-specific IgE > 3.5 kilounits/L. The proportion of asthma attributable to atopy was estimated to be 24.5% when atopy was defined by the presence of allergen-specific IgE. With a given level of specific IgE, no association between skin test reactivity and asthma was observed. Skin prick tests were less sensitive than specific IgE for detection of atopy. CONCLUSIONS: Most asthma cases in an urban underprivileged setting in Brazil were not attributable to atopy. This observation has important implications for understanding the risk factors for the asthma epidemic in Latin America.

Minor psychiatric disorders in mothers and asthma in children.

OBJECTIVE: Recent studies have shown that asthma represents a major health issue not only in children of developed countries but also in urban centers in some middle-income countries. Brazil has one of the highest prevalences of asthma worldwide. Recently, interest has grown in the relationship between psychosocial factors and asthma. This article examines the relationship between maternal mental disorders and the prevalence of asthma in low-income children from an inner city area of Salvador in the state of Bahia, Brazil, and is part of the SCAALA program (Social Change, Allergy and Asthma in Latin America). PATIENTS AND METHODS: A total of 1,087 children between the ages of 5 and 12 were investigated, together with their mothers. The mothers' mental health was evaluated using the SRQ-20, an instrument for the psychiatric screening of minor psychiatric disorders (depression, anxiety and somatic complaints). The prevalence of asthma was investigated using the ISAAC survey, a standardized, validated questionnaire for asthma and other allergic diseases. Cases were defined as asthma if the patient reported having had wheezing in the previous 12 months in addition to at least one of the following: having asthma, wheezing while exercising, waking during the night because of wheezing, or having had at least four episodes of wheezing in the previous 12 months. Atopy was defined as a positive skin prick test to allergens. RESULTS AND CONCLUSION: The presence of minor psychiatric disorders in the mothers was significantly associated with the presence of asthma in the children, and this association was consistent with all forms of asthma, irrespective of whether it was atopic or nonatopic. Future studies should be carried out to further investigate this association and the potential biological mechanisms involved. Programs for asthma control should include strategies for stress reduction and psychological support for the families of asthmatic children.