Respiratory function of infants in relation to subsequent respiratory disease: an epidemiological study.

Crying ventilatory function was measured in 487 infants shortly after birth. Over the following five years 129 infants suffered attacks of pneumonia or bronchitis. Their initial crying ventilatory function was compared with that of the 358 infants who escaped these illnesses. No statistically significant differences were found in crying ventilatory function between these two groups of infants. This has been interpreted as indicating that newborn infants who subsequently suffer attacks of pneumonia or bronchitis do not start life with deficits in their ventilatory function. In the same study crying ventilatory function was measured in 550 infants at their first birthday; 70 had suffered attacks of pneumonia or bronchitis by that age and made a clinical recovery. Their crying ventilatory function showed no consistent difference from the 480 infants who escaped their illnesses. The reasons for the lack of a difference in crying ventilatory function is discussed.