The connection between interleukin (IL) gene variations and periodontitis in individuals with or without diabetes mellitus (DM) is still uncertain. This review aimed to examine available evidence on whether genetic polymorphisms in interleukins influence periodontitis in patients with and without DM. The guiding question was: “Do IL gene polymorphisms associate with periodontitis in individuals with or without DM?” Original research articles were selected, and relevant databases were systematically searched to compile and summarize the findings. Eight studies met the inclusion criteria and were analyzed. Results were inconsistent: two studies indicated that IL-1B polymorphisms worsen periodontitis in type-2 DM patients, while another two reported minimal or no effect of these polymorphisms. Additionally, two studies found no overlapping susceptibility between IL genes, periodontitis, and type-2 DM. One study highlighted that inadequate oral hygiene, rather than genetic factors, primarily drives periodontitis in both DM and non-DM populations. Notably, seven studies exhibited a high risk of bias. In conclusion, the influence of IL gene polymorphisms on the onset and progression of periodontitis in patients with and without diabetes mellitus remains inconclusive and warrants further investigation.
