Inverse association between periodontitis and respiratory allergies in patients with type 1 diabetes mellitus

Aim: In a general adult population, we have demonstrated an inverse association between periodontitis and respiratory allergies that is in line with the hygiene hypothesis suggesting a protective effect of infections against the development of allergies. The objective of the present study was to investigate the association between periodontitis and respiratory allergies in a type 1 diabetes mellitus population. Material and Methods: The study population comprised 170 patients with type 1 diabetes mellitus aged 17–80 years. Respiratory allergies were present in 22 subjects. The attachment loss (AL) was measured. Periodontitis was defined according to the percentage of surfaces that exceeded 3 mm AL (healthy, mild, moderate, severe periodontal conditions). Results: Our adjusted analyses revealed an inverse association between periodontitis and respiratory allergies. For increasing AL, a trend towards a decreasing risk was present for respiratory allergies (p_trend<0.05). Compared with subjects with healthy periodontal conditions, individuals with severe periodontal conditions had the lowest risk of respiratory allergies [odds ratios (OR) 0.06 (95% confidence interval (CI) 0.01–0.39)], followed by subjects with moderate AL [OR 0.14 (95% CI 0.03–0.63)] and mild AL [OR 0.32 (95% CI 0.09–1.08)]. Conclusion: There is a strong inverse association between periodontitis and respiratory allergies in patients with type 1 diabetes mellitus. These findings further support the hygiene hypothesis.