A case–control study investigated gene-environment interplay amid moderate or severe periodontitis, adiponectin (ADIPOQ)-rs1501299 and leptin receptor (LEPR)-rs1137100 polymorphisms on type 2 diabetes and found an increased risk even after adjustment for smoking status, gender, age, economic status, BMI, hypertension and alcohol consumption [116]. Here, ADIPOQ is linked to periodontitis.