The Effect of Low Altitude on the Performance of Lung Function in Alaghwar Region, Dead Sea, Jordan

Background: Alaghwar region is the lowest area in the world inhabited by permanent population at the level of the Dead Sea area, which is -420 m (-1,378 ft) below sea level. The reduced barometric pressure, density of air and the degree of acclimatization are associated with the low altitude. These factors are essential for the evaluation of a lung function tests at different altitudes. Objectives: The main aim of this study was to assess the effect of this unique feature of very low altitude (LA) on the performance of lung function. Methods: A comparative cross sectional design was chosen as the epidemiological design, and the standard cluster sampling technique was used to select the study population. Study was conducted on 1493 subjects (319 exposed to LA, and 1174 living at HA). Data were collected using predesigned questionnaire on personal and sociodemographic characteristics and smoking habit; as well as measurements of forced spirometry [time-volume curve and flow volume curve), and anthropometric measurements, using standard techniques and equipment. The data was analyzed using SPSS software (IBM, version 22), and multiple regression statistical subroutine, was used. Level of significance for the present study was 0.05. Results: After allowing for the effect of age, height, gender and smoking habit, people residing in low altitude area had significantly higher lung function indices compared to those residing at high altitude areas. Smoking was found to have significant negative effect on the different indices of lung function mainly of obstructive type. Conclusions: The increased barometric pressure, decreased density of air and the degree of acclimatization have shown an increment in most pulmonary function indices at low altitude. Basically high altitude may play a role in altering ventilatory function. However, additional factors like smoking should be considered.