Trends in prevalence and severity of childhood asthma

摘要: Abstract Objective: To test the null hypothesis and there has been no change in prevalence or severity of childhood asthma over recent years. Design: Repeated population survey with questionnaires completed by parents followed home interviews parents. Setting: London borough Croydon, 1978 1991. Subjects: All children one year state private primary schools aged 7 1/2 to 8 years at screening survey. Main outcome measures: Trends symptoms, acute severe attacks, chronic disability. Results: For 1991 respectively, response rates were 4147/4763 3070/3786, obtained from 273/288 319/395 currently wheezy children. Between significant relative increases ratios 12 month attacks wheezing (1.16; 95% confidence interval 1.02 1.31), episodes (1.78, 1.15 2.74), night waking (1.81; 1.01 3.23) but not frequent (>=5) past (1.05; 0.79 1.40). There substantial decreases months absence school more than 10 days due (0.52; 0.03 0.90), any bed (0.67; 0.44 1.01), restriction activities (0.51; 0.31 0.83) an equivalent fall speech limiting 0.24 1.11). Conclusion: The small increase relatively greater persistent suggests a environmental determinants asthma. In contrast paradoxically frequency remains unchanged are indications that disability have fallen about half; this may be improvement treatment received