Table 4 Summary of studies assessing the prevalence of sensitization to specific aeroallergens

Charpin et al. (1991) [45]

933

France, a coastal town and a town at 1,326 m in the Alps

Prevalence of ENT and respiratory symptoms, positive SPT to pollens or HDM

Ozkaya et al. (2015) [46]

1,121

Turkey, a major city on the coast and another city at 1,800-2,000 m

Questionnaire evaluating asthma prevalence, SPT, total IgE

Duenas-Meza et al. (2018) [47]

61, all with severe asthma

Colombia, all living at high altitude (2,500-3,500 m)

Questionnaire assessing asthma clinical manifestations and control, baseline and post-bronchodilator spirometry, SPT, total serum IgE, FeNO

Abiad et al. (2020) [49]

919, all asthmatic

Lebanon, the population was subdivided between those living below or above 900 m

SPT for aeroallergens to evaluate atopy in asthmatic patients

Ochoa-Avilés et al. (2020) [50]

353

Ecuador, a city in the Andes at 2,550 m

Questionnaire assessing asthma prevalence and clinical manifestations, SPT for aeroallergens