Incidence and prognosis of asthma and wheezing illness from early childhood to age 33 in a national British cohort.

The British national child development study (1958 cohort) is a longitudinal study of all people in England, Scotland and Wales born during one week; 3-9 March 1958. 5,801 people contributed information at ages 7, 11, 16, 23 and 33 years. Several significant correlations were established. Antepartum haemorrhage in the third trimester appeared as a risk factor for asthma at the age of 8-16 (odds ratio 2.98). Proteinuria during pregnancy appears as a risk factor for asthma at the age of 17-33 (odds ratio 1.63). Bleeding before 20 weeks is associated with a low risk of asthma before age 7 (odds ratio 0.40). The risk of asthma in childhood was strongly associated with pneumonia, hay fever and eczema. Maternal smoking during pregnancy was a significant predictor of asthma after age 16.