by Elana Gotkine

Spring and summer births are associated with development of pollinosis and summer births are associated with house dust mite (HDM) sensitization, according to a study published in the July issue of Allergology International.

Reiji Kojima, M.D., Ph.D., from the University of Yamanashi in Japan, and colleagues examined the ties between season of birth and HDM and Japanese cedar pollen (JCP) sensitization, allergic rhinitis, and pollinosis among 4,323 participants in the Sub-Cohort Study of the Japan Environment and Children's Study. Vitamin D levels and allergen exposure were taken into account.

The researchers found that compared with participants born in winter, those born in spring or summer were more likely to have pollinosis (adjusted odds ratios for spring and summer, 2.08 and 1.89, respectively). HDM sensitization was more likely among those born in summer versus winter (Dermatophagoides pteronyssinus 1: adjusted odds ratio, 1.53; Dermatophagoides farinae 1: adjusted odds ratio, 1.44). Exposure to JCP was associated with pollinosis, and exposure to HDM was associated with HDM sensitization.

"Even when vitamin D and allergen exposure were taken into account, spring and summer births were each associated with the development of pollinosis, and summer birth was associated with HDM sensitization, suggesting the involvement of season-specific mechanisms in the spring and summer other than pollen exposure and vitamin D. Further studies should be conducted to account for the potential influence of weather conditions and respiratory infections during infancy," the authors write.

More information: Reiji Kojima et al, Effect of birth season on allergic rhinitis and cedar pollinosis considering allergen and vitamin D exposure: The Japan Environment and Children's study (JECS), Allergology International (2023). DOI: 10.1016/j.alit.2023.01.003

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