Integrating Clinical and Epidemiologic Data on Allergic Diseases Across Birth Cohorts: A Harmonization Study in the Mechanisms of the Development of Allergy Project

The numbers of international collaborations among birth cohort studies designed to better understand asthma and allergies have increased in the last several years. However, differences in definitions and methods preclude direct pooling of original data on individual participants. As part of the Mechanisms of the Development of Allergy (MeDALL) Project, we harmonized data from 14 birth cohort studies (each with 3-20 follow-up periods) carried out in 9 European countries during 1990-1998 or 2003-2009. The harmonization process followed 6 steps: 1) organization of the harmonization panel; 2) identification of variables relevant to MeDALL objectives (candidate variables); 3) proposal of a definition for each candidate variable (reference definition); 4) assessment of the compatibility of each cohort variable with its reference definition (inferential equivalence) and classification of this inferential equivalence as complete, partial, or impossible; 5) convocation of a workshop to agree on the reference definitions and classifications of inferential equivalence; and 6) preparation and delivery of data through a knowledge management portal. We agreed on 137 reference definitions. The inferential equivalence of 3,551 cohort variables to their corresponding reference definitions was classified as complete, partial, and impossible for 70%, 15%, and 15% of the variables, respectively. A harmonized database was delivered to MeDALL investigators. In asthma and allergy birth cohorts, the harmonization of data for pooled analyses is feasible, and high inferential comparability may be achieved. The MeDALL harmonization approach can be used in other collaborative projects.

Exposure to organophosphate and polybrominated diphenyl ether flame retardants via indoor dust and childhood asthma

Although the ubiquitous detection of polybrominated diphenyl ether (PBDE) and organophosphate flame retardants (PFRs) in indoor dust has raised health concerns, only very few epidemiological studies have assessed their impact on human health. Inhalation of dust is one of the exposure routes of FRs, especially in children and can be hazardous for the respiratory health. Moreover, PFRs are structurally similar to organophosphate pesticides, which have been associated with allergic asthma. Thus, we investigated whether the concentrations of PFRs and PBDEs in indoor dust are associated with the development of childhood asthma. We selected 110 children who developed asthma at 4 or at 8 years old and 110 matched controls from a large prospective birth cohort (BAMSE - Barn, Allergy, Milieu Stockholm Epidemiology). We analyzed the concentrations of 7 PFRs and 21 PBDEs in dust collected around 2 months after birth from the mother's mattress. The abundance rank in dust was as follows: TBOEP⪢TPHP>mmp-TMPP>EHDPHP~TDCIPP>TCEP~TCIPP~BDE-209⪢BDE-99>BDE-47>BDE-153>BDE-183>BDE-100. There was no positive association between the FRs in mattress dust and the development of childhood asthma. In contrast, dust collected from mattresses of the mothers of children who would develop asthma contained significant lower levels of TPHP and mmp-TMPP. This study provides data on a wide range of PFRs and PBDEs in dust samples and development of asthma in children.

IgE antibodies in relation to prevalence and multimorbidity of eczema, asthma, and rhinitis from birth to adolescence

BACKGROUND

Eczema, asthma, and rhinitis affect a large proportion of children, but their prevalence varies with age. IgE antibodies are also common in the pediatric population. However, the links between IgE, disease, and trajectories are unclear.

OBJECTIVE

To better understand the links between sensitization and disease, we studied IgE sensitization ever in relation to eczema, asthma, and rhinitis, in children followed up to 16 years of age.

METHODS

From the Swedish population-based birth cohort BAMSE, 2607 children were included. Parental reports from six time points between 1 and 16 years were used to identify children with eczema, asthma, and rhinitis. Blood was collected at 4, 8, and 16 years, and sensitization ever was defined as allergen-specific IgE ≥0.35 kUA /l to common food and/or inhalant allergens at any time point. Odds ratios for eczema, asthma, rhinitis, and multimorbidity in relation to sensitization ever were calculated using generalized estimating equations.

RESULTS

Fifty-one percent were sensitized at least once up to 16 years. Almost a quarter of ever-sensitized children did not have any disease. After adjustment for potential confounders, sensitization ever was significantly associated with the following: (i) eczema throughout childhood, (ii) multimorbidity of eczema, asthma, and rhinitis from 1 to 16 years (OR for multimorbidity: 5.11, 95% CI: 3.99-6.55), (iii) asthma and rhinitis from 4 to 16 years of age.

CONCLUSIONS

Specific IgE is strongly associated with eczema and allergic multimorbidity throughout childhood and with asthma and rhinitis from age 4 years. However, 23% of the children with IgE sensitization do not develop any disease in childhood.

Experiences of living with asthma - a focus group study with adolescents and parents of children with asthma

OBJECTIVE

The goal for asthma treatment is that every individual, so far as possible, shall live without symptoms and exacerbations. Patients and health care professionals sometimes have different perceptions of what is important for achieving good quality of life. This work aims to describe the experiences among adolescents as well as those of parents with young children living with asthma.

METHODS

Four focus group interviews were performed, two with parents of young children and two with adolescents. The data were qualitatively analyzed, using Systematic Text Condensation.

RESULT

Three themes relevant to the participants' experiences of living with asthma were presented; strategies, frustrations and expectations. The adolescents wanted to be like their peers and developed their own strategies for self-management of asthma, which included not always taking medication as prescribed. The parents emphasized frustration regarding not being believed, lack of understanding feelings of loneliness, or anxiety. One identified expectation was that the participants wanted to be met with competence and understanding in asthma care from health care professionals. Another expectation expressed among parents was that teachers in nursery and primary schools should have more knowledge and understanding on how to care for children with asthma.

CONCLUSION

Living with asthma leads to developing personal strategies in self-management of asthma. Moreover both parents and adolescents had expectations of being met by competent and understanding health care professionals. Developing a partnership between patients and health care professionals could be a successful way to improve the care of patients with asthma.

Parents and school children reported symptoms and treatment of allergic disease differently

OBJECTIVE

To examine the difference between children and their parents in reporting symptoms and treatment of allergic diseases within a longitudinal birth cohort.

STUDY DESIGN AND SETTING

Information on symptoms and treatment of asthma, rhinitis, and eczema was obtained by questionnaire from 2,744 children (mean age: 12 years) and their parents. Differences between the responses were computed, and agreement assessed both absolutely and with kappa coefficient.

RESULTS

On 12 of the 15 questions, children's and parents' reports differed significantly. Asthma-related issues appeared significantly more prevalent in the children's reports, although kappa values were fair to very good. For symptoms of allergic rhinitis, the prevalence pattern varied, and kappa values were moderate to good. Parents reported a higher prevalence of eczema-related issues, but the children reported a significantly higher prevalence of eczema itself. Kappa values ranged from moderate to good.

CONCLUSION

Although reports of allergic symptoms and treatment by 12-year-old children and their parents were in moderate-to-good agreement, children reported more symptoms than their parents. Symptoms of allergic disease should be reported by children themselves, from the age of 11 years, whereas questions of prescribed pharmacological treatment could be answered either by the children or their parents.

Adherence to national guidelines for children with asthma at primary health centres in Sweden: potential for improvement

BACKGROUND

Although asthma is the most common chronic paediatric disease in Western Europe, the extent of adherence to guidelines for primary care management of paediatric asthma remains unclear.

AIMS

To evaluate adherence to national guidelines for primary care management of children with asthma.

METHODS

This survey involved 18 primary healthcare centres in Stockholm, Sweden. The medical records of 647 children aged 6 months to 16 years with a diagnosis of asthma, obstructive bronchitis, or cough were selected and scrutinised. 223 children with obstructive bronchitis or cough not fulfilling the evidence-based criteria for asthma were excluded, yielding a total of 424 subjects. Documentation of the most important indicators of quality as stipulated in national guidelines (i.e., tobacco smoke, spirometry, pharmacological treatment, patient education, and demonstration of inhalation technique) was examined.

RESULTS

Only 22% (n=49) of the children 6 years of age or older had ever undergone a spirometry test, but the frequency was greater when patients had access to an asthma nurse (p=0.003). Although 58% (n=246) of the total study population were treated with inhaled steroids, documented patient education and demonstration of inhalation technique was present in 14% (n=59). Exposure to tobacco smoke was documented in 14% (n=58).

CONCLUSIONS

This study reveals a substantial gap between the actual care provided for paediatric asthma and the recommendations formulated in national guidelines.

Development and comorbidity of eczema, asthma and rhinitis to age 12: data from the BAMSE birth cohort

BACKGROUND

Allergy-related diseases are a public health issue, but knowledge on development and comorbidity among children is scarce. The aim was to study the development of eczema, asthma and rhinitis in relation to sex and parental allergy, in a population-based cohort, during childhood.

METHODS

At 1, 2, 4, 8 and 12 years, parental questionnaires were used to obtain data on allergy-related diseases. Complete data for all five follow-up occasions were available from 2916 children. Odds ratios for the risk of any allergy-related disease in relation to heredity and sex were calculated using generalized estimating equations.

RESULTS

At 12 years, 58% of the children had had eczema, asthma and/or rhinitis at some time. Disease turnover was high for all three diseases throughout the study. Comorbidity increased with age, and at 12 years, 7.5% of all the children were affected by at least two allergy-related diseases. Parental allergy was associated with increased comorbidity and more persistent disease and increased the risk of having any allergy-related disease (adjusted OR 1.76; 95% CI 1.57-1.97) up to 12 years. Male sex was associated with an increased risk throughout childhood. Boys and girls did not differ in disease persistence, and for comorbidity, the differences were minor.

CONCLUSIONS

Allergy-related diseases may affect a majority of children. Eczema, asthma and rhinitis develop dynamically throughout childhood, and allergic comorbidity is common. These findings indicate that allergy-related diseases should be neither seen nor studied as isolated entities.

Peanut oil in vitamin A and D preparations: reactions to skin test and manifestation of symptoms

The aim of this study was to establish whether there is a link between sensitisation to peanut and exposure to peanut oil in vitamin A and D preparations. Forty-one children with a positive in vivo or in vitro test towards peanut were included. Twenty-one children had consumed vitamins A and D in oil solution, 14 in water solution, and 6 both types. Refined and unrefined peanut oils were obtained and skin prick test extracts were prepared. None of the children exhibited a positive SPT in response to the refined peanut extract. In contrast, 15 children exhibited a positive SPT to the unrefined extract. There was no significant difference in the number of children reacting clinically to peanut exposure who had received vitamins A and D in oil-based or water-based formulations. However, children with clinical allergy to peanut and who had exclusively consumed vitamin A and D in peanut oil, exhibited a greater number of different allergic symptoms upon consumption of peanut compared with clinical allergic children who had consumed the vitamins in water solution or both types (p<0.01). This study indicates that sensitisation to peanut during childhood through consumption of vitamins A and D in oil-based solution seems unlikely, but its consumption may contribute to the development of a wider range of clinical symptoms due to peanut exposure.