Background Periodontitis is an infection with systemic effects and a high prevalence among adults. In the aetiology of allergic diseases the hygiene hypothesis claims that infections in early infancy may protect against allergic diseases.
Objective The aim of the present analyses was to investigate the independent relation between periodontitis and respiratory allergies such as hayfever, house dust mite (HDM) allergy and asthma.
Methods From the Study of Health in Pomerania (SHIP) a total number of 2837 subjects aged 20 to 59 years were included in the analysis. In our study population 326, 111 and 114 subjects were classified as suffering from hayfever, HDM allergy or asthma, respectively. The attachment loss (AL) were measured. Periodontitis was defined according to the percentage of surfaces which exceeded 3 mm AL [healthy: 0–7.7%, mild: 7.8–28.6%, moderate: 28.7–63.9%, severe: >63.9%]. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression.
Results After adjustment for confounding factors these analyses revealed inverse associations between periodontitis and hayfever as well as periodontitis and HDM allergy. For increasing AL, a trend of decreasing risk could be observed for hayfever (healthy: reference; mild AL: OR 0.87 [95%-CI 0.6–1.2]; moderate AL: OR 0.80 [95% CI 0.6–1.2]; server AL: OR 0.53 [95% CI 0.3–0.9]; Ptrend=0.01) and for HDM allergy (healthy: reference; mild AL: OR 0.80 [95% CI 0.5–1.3]; moderate AL: OR 0.64 [95% CI 0.3–1.2]; server AL: OR 0.39 [95% CI 0.2–0.9]; Ptrend=0.02). Furthermore, for asthma were observed a slightly inverse association in the full-adjusted model (healthy: reference; mild AL: OR 1.10 [95% CI 0.6–2.0]; moderate AL: OR 0.96 [95% CI 0.5–1.8]; server AL: OR 0.48 [95% CI 0.2–1.0]; Ptrend=0.11).
Conclusion There is an inverse association between periodontitis and respiratory allergies. Our results might support the hygiene hypothesis.