[Relationship between periodontitis and glomerular filtration rate in non-diabetic Chinese elderly patients in Beijing community]

Objective: To investigate the correlation between clinical periodontal indexes of periodontitis and glomerular filtration rate (GFR) in a non-diabetic elderly population in four communities of Shijingshan, Beijing. Methods: This was a cross-sectional study. Questionnaires, blood biochemical examinations, and periodontal indexes were conducted in elderly people (35 to 84 years old) in four communities of Shijingshan, Beijing between May and July 2005. Non-diabetic patients with fasting blood glucose<6.1 mmol/L, postprandial blood glucose<7.8 mmol/L, and ≥ 10 remaining teeth were included. Patients with diabetes, fasting blood glucose ≥6.1 mmol/L or postprandial blood glucose ≥7.8 mmol/L, and total residual teeth less than 10 were excluded. A total of 362 study subjects met the inclusion criteria. The survey subjects were selected by convenient sampling method. The mean full-mouth probing depth (PD), bleeding index (BI), attachment loss (AL), and plaque index (PLI), as well as PD≥4 mm% (the number of sites with PD≥4 mm as a percentage of the total number of sites in full mouth), PD≥5 mm%, PD≥6 mm%, AL≥3 mm%, AL≥4 mm%, AL≥5 mm% and AL≥6 mm% were used for the analysis. Serum creatinine values was used to calculate GFR. GFR≥90 ml/(min·1.73 m²) was defined as normal group and GFR<90 ml/(min·1.73 m²) was defined as reduced group. Univariate analysis was conducted between two groups. Multivariate regression analysis was performed with GFR as dependent variable and adjusted for risk factors such as age, sex, smoking, waist-hip ratio and physical activity. Results: There were 164 subjects in the normal GFR group (45.3%) and 198 in the reduced GFR group (54.7%). Percentage of males in the reduced GFR group, 118 in total, accounting for 59.6%, were significantly higher than in the normal GFR group (73, 44.5%)(P=0.004). The median of age, uric acid, triglyceride, and waist-to-hip ratio (65 years, 323 mmol/L, 1.73 mmol/L, 0.90) were significantly higher in the reduced GFR group than in the normal GFR group (54 years, 277 mmol/L, 1.45 mmol/L, 0.88) (P<0.05). The median of PD mean, AL mean, BI mean, PD≥4 mm%, AL≥3 mm%, and AL≥4 mm% in the reduced GFR group were 2.80 mm, 2.52 mm, 2.06, 20.4%, 46.5%, and 30.4%, respectively, which were significantly higher than those in the GFR normal group (2.60 mm, 2.37 mm, 1.93, 16.6%, 42.9%, 28.9%) (P<0.05). After adjusting for confounding factors such as age, gender, smoking, waist-to-hip ratio and physical activity, the results of logistic regression analysis showed that PD mean, AL mean, PD≥4 mm%, PD≥5 mm%, PD≥6 mm%, AL≥3 mm% and AL≥4 mm% of clinical periodontal indexes were significantly correlated with reduced GFR in this population (OR values were 1.765, 1.879, 1.430, 1.713, 1.771, 1.428, 1.445, respectively, P<0.05). Conclusions: In the non-diabetic elderly population in communities of Shijingshan, Beijing, clinical periodontal indexes reflecting the degree of periodontal tissue destruction were associated with a decreased level of GFR.