V. Nelen

Does the use of antibiotics in early childhood increase the risk of asthma and allergic disease

One of the mechanisms evoked to explain the increasing prevalences of asthma and allergy, in particular among children, is the ‘Western lifestyle’ or ‘hygiene’ hypothesis. As early childhood infections are assumed to hold a protective effect on the development of asthma and allergies, the use of antibiotics at that sensitive age may lead to an increased risk of asthma and allergy.

Gender differences in respiratory, nasal and skin symptoms : 6-7 versus 13-14-year-old children

ISAAC questionnaires were completed by the parents of 6432 children, aged 6–7 y and by themselves by 2864 children 13–14‐y‐old. Prevalence rates of respiratory and nasal symptoms and a diagnosis of asthma and hay fever were higher in 6–7‐y‐old boys than in girls, while girls aged 13–14 y had higher rates for most symptoms, except asthma. Underdiagnosis of asthma in 13–14‐y‐old girls cannot be excluded as an explanation, but our data suggest under‐reporting of respiratory and nasal symptoms in 13–14‐y‐old boys.

Higher asthma occurrence in an urban than a suburban area: role of house dust mite skin allergy

Understanding of geographical differences in asthma prevalence may be helpful in explaining recent increases in the occurrence of asthma. We wondered whether differences in allergic sensitization or other factors could explain differences in reported occurrence of asthma between an urban centre and a neighbouring suburban area. From the European Community Respiratory Health Survey (ECRHS) questionnaire, responses on asthma symptoms and risk factors and results of 11 skin allergy tests were available from 656 young adults living in urban or south suburban Antwerp, Belgium. Answers to five asthma questions were selected as dependent variables, and eight personal or environmental risk factors, as well as house dust mite (HDM) allergy, as independent variables. The effect of each independent variable on the association of asthma variables with area was assessed. Prior asthma diagnosis, present asthma symptoms, the selected risk factors and HDM allergy were all more frequently recorded in urban Antwerp. Difference in HDM allergy accounted for most of the difference in prior (mostly childhood) asthma diagnosis, since correction for it decreased the odds ratio from 2.10 to 1.65. On the contrary, the regional differences in recent asthma symptoms were not explained by HDM allergy differences nor by any other factor under study. This urban-suburban comparison indicated that house dust mite allergy is a major determinant of prior (childhood) asthma, whereas factors contributing to higher urban prevalence of present asthma symptoms could not be identified. Furthermore, our results indicate that it may be inappropriate to combine data from neighbouring areas, when their similarity has not been verified.

Croup and recurrent croup: their association with asthma and allergy

Abstract The cumulative incidence (i.e. lifetime prevalence) of croup and recurrent croup (RC) was investigated by questionnaire in a large group (nu2009=u20095756) of 5–8-year-old children (mean age: 6.8u2009±u20090.6 years) and the risk for asthma and/or wheezing in children with croup and RC assessed. In a random sample of the children, skin prick testing with common inhalant allergens (nu2009=u2009614) and spirometry (nu2009=u2009305) were performed and the results were compared between children with or without croup or RC. Of the children, 15.5% had suffered from croup, while 5.0% had had RC. The cumulative incidence was higher in boys than in girls (Pu2009<u20090.05). In the children with croup or RC an increased risk for wheezing, asthma, usage of anti-asthma medication, rhinitis and hay fever was found (Pu2009<u20090.01). There was no difference in the prevalence of positive skin prick tests between children with and without croup or RC. Mean percentage predicted forced expiratory volume in 1u2009s, forced vital capacity and peak expiratory flow was not different between children with and without croup or RC. However, children who had suffered from croup (with or without wheezing) had a lower mean percentage predicted forced expiratory flow at both 50% and 75% of forced vital capacity than those without croup (Pu2009=u20090.002). A family history of hay fever, chronic bronchitis and eczema was associated with the presence of croup or RC (Pu2009<u20090.01), while this was hardly the case for a family history of asthma.nConclusion Croup and recurrent croup are associated with bronchial asthma. The association seems essentially based on the presence of hyperreactive airways and less on the presence of atopy, although the latter can be considered an aggravating factor.

Lung function measures and their relationship to respiratory symptoms in 7- and 8-year-old children

Abnormal pulmonary function in childhood is a well‐known risk factor for lung function impairment in adult life. It is therefore of clinical interest to recognize lower pulmonary function in childhood. We investigated the association between asthma‐like respiratory symptoms and the lung function parameters FVC, FEV1, and FEF25–75 in a population‐based sample of 402 schoolchildren, aged 7 and 8 years, using linear regression analyses.

Higher occurrence of asthma-related symptoms in an urban than a suburban area in adults, but not in children

In young adults, a higher occurrence of asthma-related symptoms was found in an urban than an adjacent suburban area in a survey performed in 1991. The authors now wondered whether such differences could be established in other age groups. The present study (in 1996) included 14,299 subjects, aged 5-75 yrs, of a random sample of the general population in the same two adjacent areas: the centre of Antwerp (Belgium) and its south suburban border. The standardized European Community Respiratory Health Survey (ECRHS) and International Study of Asthma and Allergies in Childhood (ISAAC) questionnaires were used to assess the occurrence of asthma-related symptoms. Higher rates were confirmed in urban compared to suburban Antwerp in adults (20-75 yrs), but no such area differences were found in children (5-8 and 12-15 yrs). Adjustment for a number of recorded risk factors did not seem to affect the area differences in asthma-related symptoms. Comparing the survey results of 1991 and 1996 in 20-44 yr old adults, the findings suggest a slight increase in reported respiratory symptoms in both areas. A higher occurrence of asthma symptoms was observed in the urban than suburban area in adults, but not in children. This might be explained by a progressive effect of long-term exposure to the urban environment. However, longitudinal studies are necessary to further clarify the factors accounting for these age-related area differences.