Periodontal, salivary and IL-6 status in rheumatoid arthritis patients. A cross-sectional study

BACKGROUND The aim of this study was to determine whether saliva interleukin-6 (IL-6) levels are elevated in patients with rheumatoid arthritis versus a control group and examine the possible relationship between the oral condition and the risk of RA. MATERIAL AND METHODS In 30 patients with RA and 30 healthy controls, different periodontal indices were recorded; sialometric measurements were taken to determine resting whole saliva, stimulated whole saliva and stimulated parotid saliva flow; and the saliva IL-6 levels were measured. Logistic regression analysis was performed, with the presence or absence of RA as dependent variable. RESULTS The patients with RA had a greater presence of bacterial plaque, a greater periodontal pocket depth, a larger percentage of medium-sized pockets, and greater periodontal attachment loss compared with the controls. Likewise, a decrease in resting and stimulated saliva flow was observed, together with an increase in saliva IL-6 levels. Logistic regression analysis reported that the plaque index is the principal differentiating factor of patients with RA. Stimulated parotid saliva flow was also significantly correlated to the presence of RA. CONCLUSIONS The patients with RA showed a greater tendency to develop periodontal disease than the controls, with lower salivary flow and higher levels of IL-6 in saliva.