ASSOCIATION BETWEEN SERUM RESISTIN LEVEL AND PERIODONTAL CONDITION CHANGE AMONG ELDERLY PEOPLE conditions associated with obesity e. g. insulin resistance [ 18 ]. It was suggested that increased serum resistin levels were correlated with developed periodontitis in elderly Japanese [ 9 ]. Furthermore, non-surgical periodontal treatment slightly decreased circulating resistin level [ 19 ]. Bleeding on probing is generally known parameter that directly reflects inflammatory condition and is considered as a predictor of periodontal disease progression in elderly [ 20 ]. We hypothesized that serum resistin level but not adiponectin might relate to the progression of periodontitis by the changing of bleeding on probing sites. However, this hypothesis has never been proved yet. Even several lines of evidence support the higher level of serum resistin in periodontitis patients, but recent reports concluded that there were almost no differences of serum resistin levels between normal VS periodontitis patients [ 21-22 ]. Whether they influence the alteration of periodontal conditions in a long-term period still has not yet been reported. The aim of the present study was to investigate whether serum resistin levels associate to the long term periodontal condition alteration.
2. Materials and Methods 2.1. Study design and participants The present cohort, parallel design study was performed as part of the Niigata elderly study. A total of 161 Japanese elderly residing in Niigata, Japan and aged 76 at baseline participated during the entire period of the present study. Our inclusion criteria were healthy individuals and the exclusion criteria included any severe systemic disease( s) or disability condition( s). Ethical approval was obtained from the Niigata University Review Board( 21-R13-09-08) and all procedures were undergone in the Niigata University Hospital. After the participants signed the informed consent, they were asked to answer the general / oral health questionnaires. The diagnosis of periodontitis was based on the criteria as designed by the American Academy of Periodontology in 1999 [ 23 ].
2.2. Periodontal Examination Four trained dentists were involved in this study and were calibrated for periodontal examination until the kappa value for probing pocket depth ≥0.8 was reached. All remaining teeth were subjected to 6 sites / tooth examination. The measurements of the probing pocket depth( PD) were based on nearest millimeter intervals and all sites with bleeding on probing( BOP) were also recorded. Periodontal examinations were conducted at baseline and at the 4th-year follow-up examinations. Analyses were performed by another dentist who was not involved in the patient clinical outcome measurements.
2.3. Biological measurement Blood samples were taken and kept at-70 ° C until subsequent measurements of HbA1c, adiponectin, resistin, IL-6 and TNF-α by KHP0041, KHP0051, KHC0064 and KHC3014 ELISA kits( Biosource International Inc., CA, USA), respectively. Before measurements, the validation of the method was performed by fabrication of standard curve following the instruction from
Table 1. Basic characteristics, HbA1c and periodontal characteristics of the study participants at baseline
Characteristics
General characteristics
Overall
LR(< 5.3 ng / mL) N = 84
Resistin
HR( ≥5.3 ng / mL) N = 48
Male / female 64 / 68 40 / 44 24 / 24
Number of present teeth
Alcoohol drinking(%)
20.53 ± 5.87 20.36 ± 5.67 20.83 ± 6.21
64.12 64.29 63.83
Smocking(%) 44.70 46.43 41.67 HbA1c(%) 5.22 ± 0.70 5.27 ± 0.81 5.13 ± 0.46 BMI( kg / m 2) 22.69 ± 2.62 22.75 ± 2.69 22.59 ± 2.51
Serological parameters
Adiponectin(µ g / mL)
11.09 ± 4.82 11.17 ± 4.80 10.97 ± 4.88
TNF-α( pg / mL) 0.97 ± 1.59 0.94 ± 1.80 1.03 ± 1.14
IL-6( pg / mL) 0.75 ± 1.89 0.75 ± 1.97 0.76 ± 1.75 Data expressed as mean ± standard deviation
BMI = body mass index, HbA1c = glycated hemoglobin, HR = high serum resistin, IL-6 = interleukin-6. LR = low serum resitin, TNF-α = tumor necrosis factor alpha
the manufacturer. All serological parameters were measured once at the baseline period.
2.4. Health Status Interview At baseline and at 4th-year, the participants were asked to participate in an annual health examination which includes a general health check-up and the oral health questionnaires. We included the questions about receiving dental( including periodontal) treatment and recent tooth loss in the questionnaires as well in order to evaluate the oral health maintenance manner of subjects.
2.5. Statistical Analysis For continuous variables, the t-test was used for intergroup comparisons. Categorical variables comparisons between groups were conducted using Chi-square test. For association between baseline serum resistin level and periodontal condition after 4 years, multiple linear regression models were used to predict changes of sites with PD≥4 mm and sites with PD≥4 mm concomitant BOP by the influence of serum resistin, adiponectin, IL-6, TNF-α level and number of tooth loss. The P-value < 0.05 was determined as statistically significant. All statistical analyses were conducted using the STATA software package( Stata Corp., www. stata. com).
3. Results A total of 132 participants( 64 male and 68 female) were included in the present study because 29 participants were totally edentulous individuals. Almost all participants were non-diabetic because the average HbA1c at baseline was 5.22 ± 0.70 %. Only 5 participants( 3.8 %) had HbA1c level more than 6.7 %( a cut-off point of increased risk of hypoglycemia according to the Japanese Diabetes Diagnostic Criteria( 1999) [ 24 ]. Of these, 84 participants were classified into a low resistin group( LR),( with an
Original Article
Stomatology Edu Journal
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