Original Paper: Cumulative incidence of asthma diagnosis at the age of seven in a birth cohort

Abstract

Objectives: The aim of this study was to follow a cohort of children in a defined region from birth up to the age of seven for the occurrence of a doctor's diagnosis of asthma in the medical records in primary healthcare and hospital.

Methods: In a defined region in Sweden with a population of about 150,000 inhabitants, all children (n=2104) born in the University Hospital in 1990 were recorded. Seven years later, 82% (n=1752) were still living in the region; their medical files at the Department of Paediatrics and all primary healthcare centres in the region were checked for an asthma diagnosis (ICD 9).

Results: The results gave a total cumulative asthma incidence of 10.9% among seven-year-old children in the studied region. A significantly (p<0.01) higher number of boys (13.1%) than girls (8.5%) had this diagnosis. The incidence of asthma was highest (p<0.005) among boys living in urban areas at the age of seven. Increased relative risks for asthma were also found among children born in the autumn (p<0.05) and children born of young mothers (p<0.0001).

Conclusions: These results indicate a higher childhood asthma incidence than previously presented figures for Sweden and illustrate the importance of collaboration between general practitioners in primary healthcare and paediatricians in hospitals in order to cope with the disease in diagnostic, curative and preventive respects.

Key Words:

• childhood asthma
• cohort study
• general practice
• hospital care
• primary care