AimThis study explored the prevalence of atopic and nonatopic asthma in 12‐year‐old children and whether they were associated with different risk factors. In particular, we wanted to analyse whether receiving antibiotics during the first week of life was associated with asthma at that age.MethodsData were obtained from a longitudinal cohort study of 5654 Swedish children born in 2003. The parents answered questionnaires from the age of six months until 12 years. The response rate at 12 years was 3637/4777 (76%).ResultsAt 12 years, 6.4% reported current doctor‐diagnosed asthma. Treatment with antibiotics during the first week of life was associated with an increased risk of atopic asthma, with an adjusted odds ratio of 2.2 and 95% confidence interval of 1.2–4.2. Being born small for gestational age was associated with an increased risk of nonatopic asthma, with an adjusted odds ratio of 3.8 and 95% confidence interval of 1.1–13.7. Asthma that only occurred with colds was reported by 28%.ConclusionAntibiotic treatment during the first week of life was associated with an increased risk of atopic asthma at 12 years, suggesting an immune‐mediated effect. Being born small for gestational age increased the risk of nonatopic asthma.

Allergic rhinitis affected > 20% of 12-year-olds, but was lower in children who ate fish at 12 months or grew up on a farm with farm animals.

Aim Inhaled corticosteroids have resulted in the improved control of asthma and a reduced need for hospitalisation. This study aimed to examine the prevalence of uncontrolled asthma and factors that affect asthma control. Methods The data came from a longitudinal cohort study of children. The parents answered questionnaires from age 6 months to 12 years. The response rate at age 12 years was 76% (3637/4777) and doctor‐diagnosed asthma was reported in 6.4% (n = 233). Asthma control was examined with the Asthma Control Test (ACT), where scores below 20 denote uncontrolled asthma. Results Of the children with asthma at age 12 years, 15% had an ACT value below 20, that is uncontrolled asthma. Independent risk factors for uncontrolled asthma were wheeze triggered by exercise (adjusted OR, aOR 5.6; 1.9–16.6), cat at home (aOR 3.5; 1.2–10.0) and current doctor‐diagnosed rhinitis (aOR 2.8; 95% CI 1.1–7.0). A higher education in the parents reduced the risk of uncontrolled asthma (aOR 0.3; 95% CI 0.1–0.8). Only six children (i.e. 2.6%) reported hospitalisation due to asthma during the last year. Conclusion Of the children with asthma, 15% had uncontrolled asthma. Higher education in the parents was associated with better asthma control in the children.

Background Much of our knowledge of childhood asthma comes from questionnaire‐based studies. Our main aim was to assess the agreement between parental‐reported data at 12 years of age and data from two national Swedish registers. Methods Data were obtained from the prospective, longitudinal, population‐based Children of Western Sweden cohort, which focused on children born in 2003. The parents answered questionnaires at six months and one, four, eight and 12 years of age. Personal identity numbers linked 3634 children to the Swedish Prescribed Drug Register (SPDR) and the National Patient Register (NPR). Results At 12 years of age, there was substantial overall agreement between the asthma medication reported by the parents in the questionnaire and the SPDR for any asthma medication (94.8%, kappa 0.71) and maintenance treatment (95.3%, kappa 0.68). In contrast, the agreement between the outpatient asthma diagnoses in the NPR and the questionnaire‐based asthma was 30.5% and it was 32.8% between the NPR and the dispensed asthma medication in the SPDR. Hospitalization was rare for obstructive diseases after early childhood, and 38.2% of the 12‐year‐old children only received a short‐acting beta agonist, with no maintenance treatment. Conclusion There was good agreement between the questionnaire‐based data on asthma medication and the national drug register, but the National Patient Register provided incomplete information on asthma diagnoses, probably because it did not include primary care diagnoses. The results show that well‐constructed parental questionnaires can provide reliable data on childhood asthma.