Type 2 diabetes in Sri Lanka : Genetic epidemiology and periodontal association.

Prevalence rates of type 2 diabetes and impaired fasting glyceamia (IFG) in Sri Lanka are high and an increasing number of people are succumbing to disease. Identifying people at risk of developing complications is a healthcare priority of the county to prevent morbidity and mortality. Type 2 diabetes is familiarly aggregated and maternal influence for disease transmission has been observed in European countries but not in South India. The severity of periodontitis is reported to be high when diabetes control decreases but data relating to periodontitis as a complication of diabetes is not present in this population. Periodontal associated genotype (PAG), presence of allele 2 of both {ILIA (+4845) &amp; IL1B (+3954)}) is positively associated with periodontal disease in some populations but ruled out in other populations. Heightened levels of TNF-? level have been observed in both patients with type 2 diabetes and periodontitis.This study aimed to determine familial aggregation of type 2 diabetes and parental influence of disease transmission in the Sri Lankan population. The project also aimed to investigate periodontal status in diabetic patients and the effect of glycaemic control on periodontal status. The final aim of the project was to investigate the role of cytokine polymorphisms PAG and TNFA (-308) in association with periodontitis in people with type 2 diabetes.Family history data for one thousand patients was collected and analyzed. Subjects with established diabetes were recruited to the periodontal study (n=285) with an age and sex matched control population (n=72). All subjects underwent both periodontal and general health examination. Their periodontal parameters and metabolic parameters were measured including blood pressure, TG and LDL values. Patients were genotyped by PCR/RFLP method.The results of the study indicated that 59.4% of the diabetic subjects had at least one affected first degree relative in the family. It was also observed that 15.6% of mothers transfer the disease compared to (12.5%) of fathers (p<0.001). When both parents had diabetes the early age of onset of diabetes is observed among offspring compared to offspring of maternal, paternal and no parental history of diabetes respectively (p<0.05). 16.67% (12/72) of the control patients were identified as IFG and 66.67% (8/12) of this group were diagnosed with periodontitis. Systolic BP, diastolic blood pressure and LDL values were significantly lower in patients than controls (P<0.05). Triglyceride levels were significantly higher in patients with diabetes than controls (p=0.001). A higher number of diabetic subjects were affected with chronic periodontitis (33.3%) compared to the non diabetic population (21.7%) (p=0.077). People with diabetes had significantly higher mean recession, percent bleeding on probing (BOP), maximum Probing depth (PD), PD > 4mm, PD >5mm and maximum loss of attachment (LOA) scores than the non diabetic population (p0.05). Subjects with periodontitis were significantly older than those with gingivitis or periodontally healthy (p<.01). Only FBG values were significantly higher in subjects with chronic periodontitis compared to periodontally healthy subjects (p<.01). Population frequency analysis of allele 1 vs. allele 2 were 0.9 &amp; 0.1 for IL1B (+3954), 0.74 and 0.26 for ILIA (+4845) and 0.91 and 0.09 for TNFA (-308) respectively. The TNFA (-308) polymorphism deviates from the frequencies observed in North British Caucasians but similar to that observed in Taiwan and Japan. PAG had no significant effect on periodontal status in diabetes and controls (p>0.05). The percentage of PAG (12.5%) is low compared to Caucasians but higher compared to Chinese population. TNFA (-308) allele distribution had no significant effect on periodontal status. TNFA (-308) genotypes were significantly correlated with HDL.The results of the present study indicate that type 2 diabetes is familiarly aggregated in the Sri Lankan diabetic population and maternal excess is observed in the transmission pattern. There is a trend towards periodontital status to be higher in the diabetic population. Severity of periodontitis is higher in people with diabetes than those without and there is an indication that periodontitis may induce hyperglycaemia. PAG distribution shows population variation and the TNFA (-308) polymorphism may be associated with diabetes.