Incidence rates and risk factors for asthma among school children: a 2-year follow-up report from the obstructive lung disease in Northern Sweden (OLIN) studies.
Studies of incidence of asthma are still limited. A longitudinal study of asthma in school children was started in 1996 in Northern Sweden. The incidence of asthma and the associated risk factors have been studied over a 2 years period. The study started with a parental questionnaire, the ISAAC questionnaire with additional questions, and a skin-prick test. The cohort, 3,525 children, 7 and 8 years old at start, was followed after 1 and 2 years by using the same questions, Each year responded 97%. The cumulative incidence of physician-diagnosed asthma was 1.7%, 0.9/1,000/year the first year, and 0.8/1,000/year the second year. The cumulative incidence of wheezing was 6.3%, and of frequent or daily users of asthma medicines 2.1%. Significant risk factors for incident asthma were a positive skin test, OR 5.64 (3.10-10.25); rhinitis,OR 3.53 (1.80-6.90); eczema, OR 2.19 (1.26-3.82); a family history of asthma, OR 2.83 (1.75-4.56); low birth weight, OR 3.38 (1.61-754); respiratory infections, OR 2.12 (1.24-3.63); male gender, OR 1.71 (1.06-2.81); and a smoking mother OR 2.00 (1.07-3.73). In summary the incidence of asthma during 2 years after age 7 was high, almost 1/100/year. Allergy was the most important risk factor, but other factors were influential.
Rönmark
E
E
Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden. eva.ronmark@nll.se
Perzanowski
M
M
Platts-Mills
T
T
Lundbäck
B
B
D000818:Animals; D000829:Animals, Domestic; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology / Q000276:immunology; D002415:Cats; D002648:Child; D004285:Dogs; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006967:Hypersensitivity / Q000150:complications / Q000175:diagnosis; D015994:Incidence; D008297:Male; D015999:Multivariate Analysis; D015995:Prevalence; D011446:Prospective Studies; D012135:Respiratory Sounds; D012141:Respiratory Tract Infections / Q000150:complications; D012307:Risk Factors; D012737:Sex Factors; D012882:Skin Tests; D012907:Smoking / Q000009:adverse effects; D013548:Sweden / Q000453:epidemiology