[1] Univ Insubria, Dept Med & Surg, Varese Como, Italy
[2] IRCCS, Allergy & Immunol Unit, Ist Clin Sci Maugeri, Pavia, Italy
[3] IRCCS, Ist Clin Maugeri, Div Pulm Rehabil, Tradate, Italy
[4] IRCCS, Ist Clin Maugeri, Clin Epidemiol Resp Dis Serv, Tradate, Italy
[5] Univ Insubria, Dept Med & Surg, Varese Tradate, Italy
[6] IRCCS, Ist Clin Maugeri, Div Pulm Rehabil, Varese Tradate, Italy