The association of month of birth with atopy in adult patients with asthma and rhinitis in Anatolia, Turkey.

BACKGROUND Exposure to allergens in early life may predispose subjects to develop allergies and diseases related to allergic sensitisation. OBJECTIVE To determine the association between month of birth and atopic sensitisation in adult Turkish patients with rhinitis and/or asthma using the diagnostic method of skin prick tests. METHODS This prospective cross-sectional study included all adult patients who underwent skin prick testing with rhinitis and asthma from November 2009 to June 2010. Sensitisation was categorised as any sensitisation, pollen sensitisation, and house dust mite sensitisation. Multivariate logistic regression model was employed with the primary predictor being month of birth. Diagnosis (asthma, rhinitis and both), age, gender and family history of atopy were considered as potential confounders in the model. The associations were presented with both unadjusted and adjusted odds ratios (OR) and their 95% confidence interval (CI). RESULTS A total of 616 subjects were evaluated. Three-hundred and forty-one subjects had sensitisation to allergens according to skin prick tests. Analyses showed that subjects born in September were less likely to have documented skin test positively with pollen sensitisation [0.27 (0.09-0.84), p=0.023]. CONCLUSION The results support the hypothesis that being born at the end of the pollen season may protect subjects from pollen sensitisation.