Role of familiarity versus interleukin-1 genes cluster polymorphisms in chronic periodontitis.

Periodontitis (PO) is a multifactorial disease affecting about 10% to 20% of the general population. Several studies have suggested that part of the clinical variability in PO might be explained by genetic factors. Among the candidate genes for PO, IL1 gene polymorphisms have been broadly investigated, with variable results, for their relationship with the disease. We studied three IL1 polymorphisms, IL1A C[-889]T (rs1800587), IL1B C[3953/4]T (rs1143634), and IL1RN VNTR [+2018] (rs419598) in relation to different life styles and familiarities. We did not find correlation between these IL1 polymorphisms and chronic PO, as well as between chronic PO and life styles (smoking, alcohol, coffee, fizzy drink and fish). We found a strong correlation, also after adjustment for age, between familiarity and PO onset (P=0.0062; OR 5.754, 95% CI 1.644-20.145). In conclusion, we did confirm the previously suggested association between PO and IL1 gene cluster polymorphisms, and between PO and four common risk factors (coffee, smoking, alcohol and fizzy drinks) and one common protective factor (fish). On the contrary, we found a strong role of familiarity.