Introduction ! Pneumothorax is defined as the presence of air in the pleural space. The term pneumothorax was first defined by Itard in 1803 and its clinical fea- tures were described by Laennec in 1819 [1]. Most investigators agree that spontaneous pneu- mothorax (SP) develops as a result of the rupture of blebs or bullae which lie immediately under the visceral pleura. There is no consensus of opin- ion on the factors responsible for the rupture of these blebs. Reported risk factors for primary spontaneous pneumothorax include smoking and height in male patients, and age and underly- ing lung disease for secondary spontaneous pneu- mothorax [2, 3]. Previous studies have suggested that weather changes can accelerate the development of SP [3, 4]. Weather changes, such as changes in atmos- pheric pressure (AP), temperature and humidity may influence the incidence of SP, as has been re- ported before [3–8]. Temperature has an influ- ence on pressure, and therefore both should be measured simultaneously. Humidity itself has not been reported to be a risk factor for the devel- opment of spontaneous pneumothorax. The aim of this study was to investigate the rela- tionship between the onset of spontaneous pneu- mothorax episodes and weather changes, such as changes in AP, temperature and humidity, in the middle Black Sea Region of Turkey. Material and Methods ! A retrospective analysis was carried out for all pa- tients admitted with the diagnosis of SP between January 2004 and January 2007 (37 months). Dur- ing this period, a total of 175 patients were iden- tified for whom the diagnosis of SP was made at the State Hospital and Chest Disease and Thoracic Surgery Hospital. The patients who had an iatro- genic or traumatic cause for their pneumothorax were excluded from the study. Pneumothorax was always diagnosed on the basis of chest radio- graph findings and physical examination. The Turkish National Institute of Meteorology provided a computer record of the meteorological Abstract ! Background: The aim of this study was to investi- gate the relationship between weather conditions and pneumothorax episodes in the patients with spontaneous pneumothorax (SP) admitted to our hospitals. Methods: One hundred and seventy-five patients diagnosed with SP and admitted to two hospitals in our area between January 2004 and January 2007 were included in this study. Data compari- son was made between the days with and with- out pneumothorax. Results: 159 of the patients (91%) were male and 16 (9%) were female. During the study a total of 202 SP episodes were observed. Pneumothorax episodes were observed mostly in autumn and in June and November out of all twelve months. There was no statistical difference in atmospheric pressure, temperature or humidity between the days with and those without pneumothorax. No statistical difference was observed in the atmos- pheric pressure changes between the days with pneumothorax. Conclusion: In our area, no relationship was ob- served between pneumothorax episodes and me- teorological conditions in cases with SP, but at- tacks were found to occur more often in certain seasons and months. We believe that more signif- icant results could be obtained if similar studies are conducted in other regions or maybe all over the country. The Role of Meteorological Conditions on the Development of Spontaneous Pneumothorax Authors B. Çelik 1 , H. Kefeli Çelik 2 , H. Hamzaçebi 3 , H. Demir 3 , K. Furtun 3 , C. Ortamevzi 4 Affiliations 1 Department of Thoracic Surgery, Ondokuz Mayıs University Medical School, Samsun, Turkey 2 Department of Anesthesiology and Reanimation, Ondokuz Mayıs University Medical School, Samsun, Turkey 3 Department of Thoracic Surgery, Samsun Chest Disease and Thoracic Surgery Hospital, Samsun, Turkey 4 Department of Thoracic Surgery, Samsun State Hospital, Samsun, Turkey Key words l " spontaneous pneumothorax l " atmospheric pressure l " temperature l " humidity received January 13, 2009 Bibliography DOI 10.1055/s-0029-1185721 Thorac Cardiov Surg 2009; 57: 409–412 © Georg Thieme Verlag KG Stuttgart · New York · ISSN 0171‑6425 Correspondence Dr. Burçin Çelik Department of Thoracic Surgery Ondokuz Mayıs University Medical School Kurupelit 55139 Samsun Turkey Phone: + 90 36 23 12 19 19/ 27 01 Fax: + 90 36 24 57 60 41 cburcin@hotmail.com 409 Çelik B et al. The Role of … Thorac Cardiov Surg 2009; 57: 409–412 Original Thoracic