Renal function and periodontal disease in elderly Japanese

Chronic renal failure involves a slow, progressive loss of renal function over months or years. It is possible that periodontal disease and chronic kidney disease might share common risk factors. This study investigated whether a link exists between periodontal disease and chronic renal function in community-dwelling elderly subjects.

A total of 145 study subjects, all 77 years of age, participated in this study. A periodontal examination was carried out by trained dentists. Urine was collected over 24 hours, and blood was taken on the morning of the dental exam. The volume of creatinine per 24 hours (Cre_U) and volume of urine per 24 hours were used as urinary markers of kidney function; serum creatinine levels (Cre_S) were used as a blood marker of kidney function. Creatinine clearance per 24 hours was calculated as Cre_U/Cre_S. In addition, biochemical parameters of bone turnover were measured: urinary deoxypyridinoline (U-DPD) as a bone resorption marker and serum osteocalcin (S-OC) as a bone formation marker. Multiple regression analysis was used to evaluate the relationship between the percentage of periodontal sites with > or =6-mm clinical attachment level (% > or =6-mm CAL) and renal function, as well as the relationship between % > or =6-mm CAL and bone metabolism. The % > or =6-mm CAL was used as the dependent variable. The number of remaining teeth, smoking habit, gender, use of interdental brushes or dental floss, volume of urine per 24 hours, and creatinine clearance per 24 hours were independent variables in the first test. In addition, the number of remaining teeth, smoking habits, gender, use of interdental brushes or dental floss, U-DPD, and S-OC were independent variables in the second test.

Multiple regression analysis showed that creatinine clearance per 24 hours and S-OC were significantly associated with % > or =6-mm CAL per person. The standardized coefficients were 0.26 (P = 0.015) and -0.27 (P = 0.006), respectively.

The % > or =6-mm CAL was significantly associated with renal function and bone metabolism markers. This study suggests that the increased incidence of chronic renal failure that occurs with age might increase the probability of severe periodontal disease in community-dwelling elderly subjects.