What have we learned from the Tucson Children's Respiratory Study?

The Tucson Children's Respiratory Study was the first longitudinal assessment of the natural history of asthma in which children were enrolled at birth. Over 1200 children were originally included and over 800 were still participating at age 13. The study has provided general indications about the most important risk factors for and the prognosis of different phenotypes associated with recurrent airway obstruction during childhood. The most important conclusion from the study is that asthma is a heterogeneous disease, with different predominant expressions at different ages. The form of the disease that is associated with atopy is not very frequent in early life, but becomes preponderant during the school years. However, this form is more persistent and is associated with significant deficits in lung function growth up to age 11. Up to two-thirds of infants who wheeze have a transient form of recurrent airway obstruction associated with low premorbid lung function. Many children who wheeze during the preschool years do so only during viral infections. These children usually have a history of wheezing due to respiratory syncytial virus during early life and low levels of lung function during the school years. Understanding the different asthma phenotypes of childhood will provide new clues for strategies for the primary prevention of the disease.