(A retrospective case control study to validate the association between Interleukin-1 gene variations and adult chronic periodontal disease in Chinese (Shanghai))

Inclusion Criteria:

- To be included in this study, an individual needs to be Han Chinese of 35 years of age or older at time of enrollment.

Exclusion Criteria:

- 1) Age younger than 35 years old. 2) Patients with diagnosis of rheumatoid arthritis, psoriasis, inflammatory bowel disease, glomerulonephritis/kidney disease, cancer, or Sjogren's syndrome.

3) Organ transplant recipients.

All study subjects will be selected from a pre-existing patient database in Shanghai. All chronic periodontitis cases and controls will be subjects who were at least 35 years old at time of enrollment.

Classification of chronic periodontitis will be based on the extent of periodontal tissue destruction with consideration of tooth loss.