Pollen concentrations and prevalence of asthma and allergic rhinitis in Italy: Evidence from the GEIRD study.
BACKGROUND
Pollen exposure has acute adverse effects on sensitized individuals. Information on the prevalence of respiratory diseases in areas with different pollen concentrations is scanty.


OBJECTIVE
We performed an ecologic analysis to assess whether the prevalence of allergic rhinitis and asthma in young adults varied across areas with different pollen concentrations in Italy.


METHODS
A questionnaire on respiratory diseases was delivered to random samples of 20-44year-old subjects from six centers in 2005-2010. Data on the daily air concentrations of 7 major allergologic pollens (Poaceae, Urticaceae, Oleaceae, Cupressaceae, Coryloideae, Betula and Ambrosia) were collected for 2007-2008. Center-specific pollen exposure indicators were calculated, including the average number of days per year with pollens above the low or high concentration thresholds defined by the Italian Association of Aerobiology. Associations between pollen exposure and disease prevalence, adjusted for potential confounders, were estimated using logistic regression models with center as a random-intercept.


RESULTS
Overall, 8834 subjects (56.8%) filled in the questionnaire. Allergic rhinitis was significantly less frequent in the centers with longer periods with high concentrations of at least one (OR per 10days=0.989, 95%CI: 0.979-0.999) or at least two pollens (OR=0.974, 95%CI: 0.951-0.998); associations with the number of days with at least one (OR=0.988, 95%CI: 0.972-1.004) or at least two (OR=0.985, 95%CI: 0.970-1.001) pollens above the low thresholds were borderline significant. Asthma prevalence was not associated with pollen concentrations.


CONCLUSIONS
Our study does not support that the prevalence of allergic rhinitis and asthma is greater in centers with higher pollen concentrations. It is not clear whether the observed ecologic associations hold at the individual level.
Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy. Electronic address: pierpaolo.marchetti@univr.it.
Pierpaolo
P
Marchetti
Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy.
Giancarlo
G
Pesce
Unit of Biostatistics and Clinical Epidemiology, Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Italy.
Simona
S
Villani
Allergy Unit, Department of Internal Medicine, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Ancona, Italy.
Leonardo
L
Antonicelli
Allergologia, Azienda Sanitaria Locale 1, Imperiese, (IM), Italy.
Renato
R
Ariano
Department of Experimental Medicine, II University of Naples, Naples, Italy.
Francesco
F
Attena
Department of Public Health and Pediatrics, University of Turin, Turin, Italy.
Roberto
R
Bono
Department of Public Health and Pediatrics, University of Turin, Turin, Italy.
Valeria
V
Bellisario
Unit of Lung Disease, Department of Clinical and Experimental Medicine, University of Sassari, Sassari, Italy.
Alessandro
A
Fois
U.O.C. di Medicina del Lavoro, Sezione di Allergologia, Fondazione Salvatore Maugeri, Pavia, Italy.
Nadia
N
Gibelli
Unit of Hygiene and Preventive, Environmental and Occupational Medicine, Department of Diagnostics and Public Health, University of Verona, Verona, Italy.
Morena
M
Nicolis
Unit of Occupational Medicine, University Hospital of Verona, Verona, Italy.
Mario
M
Olivieri
Unit of Lung Disease, Department of Clinical and Experimental Medicine, University of Sassari, Sassari, Italy.
Pietro
P
Pirina
Air pollution Unit, Agenzia Regionale per la Protezione Ambientale Campania (ARPAC), Caserta, Italy.
Eugenio
E
Scopano
Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy.
Consolata
C
Siniscalco
Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy.
Giuseppe
G
Verlato
Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy.
Alessandro
A
Marcon
D000328:Adult; D000485:Allergens; D001249:Asthma / Q000453:epidemiology*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D011058:Pollen; D015995:Prevalence; D065631:Rhinitis, Allergic / Q000453:epidemiology*; D055815:Young Adult
D000485:Allergens
Adult; Aeroallergen; Allergy; Ecologic study; Public health; Respiratory