The effect of altitude on normal pulmonary function tests: a comparison between the Dead Sea area and Amman.

The Dead Sea area, which is 350 m below sea level, is by far the lowest region in the world inhabited by permanent population. To assess the effect of that low altitude on pulmonary function, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow rate (PEFR) and forced mid-expiratory flow rate between 25% and 75% of FVC (FMF 25-75%) were determined for 195 boys and 149 girls living in the Dead Sea region. These were compared with the same function values of 204 boys and 224 girls living in Amman Area (774 meters above sea level). The data were statistically analysed, considering a probability of error level of 1% as significant. When the data for boys were considered, the arithmetic mean test showed significant difference for FVC only while the variance test showed significance in the FVC, FEV1, and FMF (25-75%), the values of the Dead Sea area subjects being lower. On the other hand when the data for girls were analysed there were no statistically significant differences between the two groups, although there was a slight apparent difference in all values, with the Dead Sea area girls having higher figures. These data suggest that, although altitude may play a role in modifying ventilatory function, other factors should be considered. In particular the inhabitants and their children of the Dead Sea area are very actively involved in agriculture while the children of Amman have few exercise facilities available.