Interleukin-1 genetic association with periodontitis in clinical practice

• Published in: Journal of periodontology (1970) Vol. 71; no. 2; p. 156
• Main Authors: McDevitt, M J, Wang, H Y, Knobelman, C, Newman, M G, di Giovine, F S, Timms, J, Duff, G W, Kornman, K S
• Format: Journal Article
• Language: English
• Published: United States 01.02.2000
• Subjects: Adult; Age Factors; Alveolar Bone Loss - ethnology; Alveolar Bone Loss - pathology; Case-Control Studies; Chromosomes, Human, Pair 2; Europe - ethnology; Female; Genetic Predisposition to Disease; Genotype; Humans; Interleukin-1 - genetics; Logistic Models; Male; Middle Aged; Odds Ratio; Periodontitis - ethnology; Periodontitis - genetics; Periodontitis - immunology; Polymorphism, Restriction Fragment Length; Smoking; United States - epidemiology; United States; Europe
• ISSN: 0022-3492
• DOI: 10.1902/jop.2000.71.2.156

Periodontitis is a bacterial disease modified by multiple risk factors. The pro-inflammatory cytokine interleukin- (IL-1) is a key regulator of the host responses to microbial infection and a major modulator of extracellular matrix catabolism and bone resorption. It has been reported that variations in the IL-1 gene cluster on chromosome 2 are associated with increased susceptibility to severe adult periodontitis. The present study evaluated the association between a composite IL-1 genotype, including allele 2 at each of two loci (IL-1A +4845 plus IL- B +3954), and a broad spectrum of periodontally healthy to diseased patients in a population that is typically encountered in a dental practice setting. Ninety patients, non-smokers or former smokers with less than 10 pack-year (pk/yr) history, were recruited from a private dental practice. The major outcome variable was bone loss determined by computerized linear measurements of radiographs. Genotypes were analyzed from finger-stick blood samples using previously reported methods. Multivariate logistic regression models demonstrated that patient age, former smoking history, and the IL-1 genotype were significantly associated with severity of adult periodontitis. For non-smokers or former light smokers (<5 pk/yr), IL-1 genotype positives were at increased odds ratio of having moderate to severe periodontal disease of 3.75 (95% CI: 1.04-13.50) to 5.27 (95% CI: 1.23-22.70), depending on ethnicity, compared to IL-1 genotype negatives. Former moderate smokers (>5 pk/yr and <10 pk/yr) who were IL-1 genotype negative were at increased odds ratio of having moderate to severe periodontal disease of 7.43 (95% CI: 1.20-46.20) compared to non-smokers or former light smokers who were IL-1 genotype negative. In addition, past smoking history was also a significant effect modifier as demonstrated by the statistically significant interaction between past smoking history status and IL-1 genotype status. This study demonstrates that the composite IL-1 genotype is significantly associated with the severity of adult periodontitis. It also confirmed that both IL-1 genotyping and smoking history provide objective risk factors for periodontal disease in a private practice environment.