Dissociating polysensitization and multimorbidity in children and adults from a Polish general population cohort

International audienceBackground: Links between multimorbidity of allergic diseases and allergen sensitization are still under debate, especially in adults. This study aimed to establish a relationship between polysensitization and allergic multimorbidity in children and adults and the allergens involved in multimorbidity.Material and method: A cross-sectional multicentre study enrolled children aged 6-7 and 13-14 years and adults aged 20-44 years from a Polish national cohort. The diagnosis of allergic diseases was made by a physician. Skin prick tests to 13 allergens and serum IgE levels to 4 allergens were tested.Results: Among the 3856 participants, single disease (asthma, allergic rhinitis or atopic dermatitis) was diagnosed in 27.7% subjects and allergic multimorbidity in 9.3%. Allergic multimorbidity occurred more commonly in children than in adults (p < 0.01). Asthma or atopic dermatitis alone were not associated with polysensitization. Rhinitis and multimorbidity were associated with polysensitization. Allergic multimorbidity occurred in 2.2% of participants with negative skin prick tests, 9.8% of those with one positive prick test (SPT ≥ 3 mm) and 20.6% of polysensitized ones (p < 0.001). There was an increasing risk of multimorbidity depending on the number of positive prick tests for both SPT ≥ 3 mm (OR 9.6-16.5) and SPT ≥ 6 mm (OR 5.9-13.7). A statistically significant relationship was found between allergic multimorbidity and sensitization to cat and mite allergens.Conclusions: Multimorbidity is associated with polysensitization especially in children compared with adults in Polish population cohort. New insights into single disease patterns were found: bronchial asthma is the strongest risk factor for the development of multimorbidity in comparison with allergic rhinitis and atopic dermatitis