Influence of height on the risk of spontaneous pneumothorax.

The risk of primary spontaneous pneumothorax was found to be greatest among persons 25 to 34 years old of each sex and greater for men than women, although a gradient of risk with increasing height was found which seemed to explain much of the male predominance in this condition. Minor physical anomalies were relatively common among these patients, but no specific clinical syndromes could be identified. For secondary spontaneous pneumothorax, the risk increased with age and was greater for men, although this may simply have reflected an increased frequency of underlying chronic pulmonary disease. The gradient of risk with height was much less pronounced for secondary spontaneous pneumothorax. Most of the patients in both pneumothorax groups smoked.