BACKGROUND: The aim of the current study is to show the prevalence of
atopy in five Spanish areas, and its variability according to area, ag
e and gender. PATIENTS AND METHODS: From a populational based sample o
f 16,884 individuals aged 20 to 44 years-old, we obtained a randomized
20% subsample (n = 3,310). Participants performed specific IgE measur
ements, skin prick tests, forced spirometries and metacholine challeng
es to measure bronchial hyperresponsiveness. The response rate was 40%
, and 1,313 individuals were finally included in the study. Specific a
topy to the following aeroallargens was determined: cat dander, Clados
porium, Dermatophagoides, Phleum, Parietaria, birch, Alternaria, ambro
sia, olive, rye grass and dog dander. RESULTS: The global prevalence o
f atopy (detectable specific antibodies IgE in serum and/or skin react
ivity) widely varied by area, skin reactivity ranking in males from a
minimum in Albacete (24.6%; 95% CI: 18-33) to a maximum in Huelva (39.
6%; 95% CI: 30-53), and in females ranking from a minimun in Galdakao
(10.3%; 95% CI: 6-17) to a maximum in Barcelona (28.8%; 95% CI: 19-43)
. Considering separately seropositivity and skin reactivity we observe
d a similar trend. Males showed a higher prevalence of global atopy (4
0.1%) than females (29.4%). Our data indicate that there is a decrease
in the prevalence of atopy according to age in the general population
, but only significant in men. Dermatophagoides pteronyssinus is the m
ost common allergen in all ares but Albacete, where the most common al
lergen is the olive pollen. CONCLUSIONS: By means of a standard method
ology, we report population data of the prevalence of atopy in five Sp
anish areas. The distribution of the prevalence of atopy varies widely
in the five areas surveyed, according to the composition of the most
common environmental allergens.