Spontaneous pneumothorax related with climatic characteristics in the Valencia area (Spain).

Spontaneous pneumothorax (SP) is a common respiratory condition that is easily recognized and treated, though the etiology remains largely unknown. Apart from individual factors, it has been suggested that changes in atmospheric pressure may trigger the onset of SP. Our aim was to examine the association between the onset of episodes of SP with atmospheric pressure changes in the general population of an area with a Mediterranean climate. A prospective survey was conducted to detect all episodes of SP in a region of Valencia (Spain) from January 1994 to January 1996. A total of 69 cases were identified; of these, 62 episodes of SP met the inclusion criteria for this survey. Climatic measurements during the two years studied were obtained from the Spanish National Meteorological Institute, including 6-hour readings of temperature, relative humidity, clear sunlight, atmospheric pressure, visibility, wind speed and rainfall. Associations were evaluated between the daily number of hospital admissions for SP and diurnal changes in atmospheric pressure involving rises and falls of as much as 7 and 10 mbar. In addition, the association of atmospheric pressure changes to time periods of 1 a.m., 7 a.m., 1 p.m. and 7 p.m. was assessed. Drops in atmospheric pressure below the fifth percentile and elevations above the ninety-fifth percentile were regarded as 'unusual'. There was no association between the development of SP and changes in atmospheric pressure, and no correlation was found with repeated exposure to unusual changes of atmospheric pressure. Further research is needed using similar methods to establish comparisons between countries with different climates.