Interleukin-1 gene cluster polymorphisms associated with periodontal disease in type 2 diabetes.
BACKGROUND
Epidemiologic studies have shown an increased frequency, severity, and risk of periodontitis in patients with diabetes. Periodontitis is associated with certain interleukin (IL)-1 gene cluster polymorphisms. Diabetes is a proinflammatory state with increased levels of circulating cytokines suggesting a causal role for inflammation in its etiology. Common genetic factors may be involved in the susceptibility for diabetes and periodontitis. We evaluated the relationships among IL-1 gene polymorphisms, type 2 diabetes, and periodontitis.


METHODS
One hundred twelve patients with diabetes and chronic periodontitis, 224 patients without diabetes but with chronic periodontitis, and 208 healthy subjects without periodontitis were studied. All received a clinical periodontal examination and assessment of standard periodontal parameters. IL-1A -889, -1B +3954, and -1B -511 polymorphisms were identified by polymerase chain reaction (PCR) amplification followed by restriction enzyme digestion and gel electrophoresis. Variable numbers of IL-1RN tandem repeats were detected by PCR amplification and fragment-size analysis.


RESULTS
The severity and extent of periodontitis was significantly greater in patients with diabetes than in patients without diabetes. No significant differences in IL-1A -899, -1B +3954, or -1RN genotype frequencies were found between patients with diabetes and patients without diabetes. The IL-1A -889 TT genotype (odds ratio [OR] = 2.90; 95% confidence interval [CI] = 1.20 to 7.02), IL-1B +3954 TT genotype (OR = 3.54; 95% CI = 1.15 to 10.85), and IL-1B -511 CC genotype (OR = 2.10; 95% CI = 1.25 to 3.58) were significantly associated with periodontitis. The presence of an IL-1 positive genotype was significantly associated with periodontitis (OR = 1.61; 95% CI = 1.04 to 2.49). No interaction between smoking status and polymorphisms was found.


CONCLUSIONS
Periodontitis was significantly associated with some IL-1 gene polymorphisms. No association between diabetes and IL-1A and -1B gene polymorphisms was found.
López
Néstor J
NJ
Department of Conservative Dentistry, School of Dentistry, University of Chile, Santiago, Chile. nlopez@interactiva.cl
Valenzuela
Carlos Y
CY
Jara
Lilian
L
D000328:Adult; D000367:Age Factors; D000368:Aged; D000483:Alleles; D016022:Case-Control Studies; D055113:Chronic Periodontitis / Q000145:classification / Q000235:genetics / Q000276:immunology*; D003596:Cytosine; D003774:Dental Plaque Index; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics / Q000276:immunology*; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D005884:Gingival Hemorrhage / Q000235:genetics / Q000276:immunology; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein / Q000235:genetics; D007375:Interleukin-1 / Q000235:genetics*; D053582:Interleukin-1alpha / Q000235:genetics; D053583:Interleukin-1beta / Q000235:genetics; D008875:Middle Aged; D017622:Periodontal Attachment Loss / Q000235:genetics / Q000276:immunology; D010514:Periodontal Pocket / Q000235:genetics / Q000276:immunology; D012150:Polymorphism, Restriction Fragment Length / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012307:Risk Factors; D012907:Smoking; D020080:Tandem Repeat Sequences / Q000235:genetics; D013941:Thymine
C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D053582:Interleukin-1alpha; D053583:Interleukin-1beta; D003596:Cytosine; D013941:Thymine