The prevalence of atopic sensitization was compared among all pupils in three urban school classes (median age 10, 12 and 14 years, respectively) and three corresponding classes in the adjacent rural district (642 pupils in all). A written questionnaire, oral interview and skin prick testing against 7 allergens were used, with skin tests performed on 93.4 % of the urban, and 92.0 % of the rural pupils. Contact with domestic animals was much more common in the rural area. Urban living was a risk factor for at least one positive skin test to pollen or animal dander, with odds ratio (OR) 1.83 and confidence interval (CI) 1.26–2.67. This was even more pronounced for children with both positive skin test and allergic symptoms (OR 2.13; CI 1.38–3.28). An increased prevalence of positive skin prick tests in the urban area compared with the rural environment was also found for 3 individual allergens, i.e. birch pollen (OR 1.78), timothy pollen (OR 1.87) and cat dander (OR 2.29). The relative risk for positive skin test in the urban area was further increased when standardized for allergic heredity, type of dwelling, daily exposure to tobacco smoke and dampness or abnormal smell in the home. This study suggests that various adjuvant factors increase the risk of sensitization in urban environments, particularly among children with a positive family history of allergy

The prevalence of asthma among 10,527 children aged 7-16 years was investigated in 1985. Children were assigned to the asthma group when replies to a questionnaire stated that at least two of four stipulated symptoms had been experienced in the preceding year. A validation study, comprising exploration of medical history, pulmonary auscultation and physiological tests (spirometry and methacholine inhalation challenge) was performed in 73 children. The overall prevalence of asthma was 4%. The most common symptom-inducing factors were physical exertion, upper respiratory tract infection, contact with animals and tobacco smoke. The methacholine test had limited value as a diagnostic aid, being positive in only 25% of children with a clear history of asthma.

The same questionnaire and study design was used in two surveys of asthma among all the children attending the 9-y compulsory school in Sundsvall in 1985 (n = 10527) and 1995 (n = 9165). A detailed questionnaire was distributed by post to the parents of all children who had answered in the affirmative to a simple screening question on asthmatic symptoms at the beginning of the autumn term. The questionnaire contained detailed questions on symptoms and asthma management. Our findings indicated a moderate increase in reported asthma-like symptoms and physician-diagnosed asthma between 1985 and 1995. The severity of symptoms was unchanged, despite a large community-based asthma campaign and a tenfold increase in the number of children receiving inhaled steroids. A validation analysis included an interview by a physician, a skin prick test, determination of specific IgE antibodies and spirometry. The oral interviews suggested that undertreatment was common. Many children had adequate medication at home, but this medication was not used properly. Finally, all 13-14-y-old children also replied to written and video questionnaires from the International Study of Asthma and Allergies in Childhood (ISAAC). It is likely that differences in study design explained the much higher prevalence of wheezing in this part of the study.

The increase in asthmatic symptoms in school children has peaked. Reduced severity of symptoms and divergent trends for wheezing and physician-diagnosed asthma suggest an increased awareness of asthma with improved management of the symptoms. However, differences in trends between allergic and nonallergic asthma could not be excluded.

In a survey of asthma among schoolchildren, a questionnaire was sent to the parents of 10,527 children aged 7-16 years. A group of 420 children with asthma was thereafter identified. Their asthma symptoms had caused little absence from school (none in the past 6 months in 60% of the group, and greater than 5 days in only 13%). During the preceding year 40% of the group had had more than 10 days of restricted physical activity due to asthma. Severe symptoms due to undertreatment were uncommon. Although 68 children were receiving no medication, most of them appeared to have only mild symptoms, and the parents requested aerosol inhaler in only ten cases. Symptoms at school were usually related to sporting activities. In 40% of the total asthma group the symptoms were unknown to the school health service before the survey. Dissatisfaction with the service was expressed by 24% of the parents of asthmatic children.