Comparison of periodontal conditions among three elderly populations in Japan and Germany

Aim: There is a growing interest in comparing periodontal conditions between countries. This study compared periodontal disease conditions in three elderly populations- one from Japan and two from Germany. Materials and Methods: We compared periodontal data of 70-year-old subjects from the Niigata Study with 65-74-year-old subjects from the Study of Health in Pomerania (SHIP) and from West Germany (DMS III). A total of 489, 399 and 549 dentate subjects were analysed, respectively. Recording protocols were standardized. Linear or logistic models were used to compare Niigata Study with SHIP. Results: Elderly German subjects in SHIP and DMS III had significantly more severe periodontal conditions and fewer remaining teeth compared to those in Niigata Study, though differences were less pronounced for DMS III. German subjects showed a significantly different pattern of various periodontal risk factors compared to Japanese subjects. Even after adjustment for putative periodontal risk factors, SHIP subjects still presented significantly higher adjusted values for most periodontal parameters compared to Niigata Study subjects (p < 0.05). Conclusions: Periodontitis was more prevalent in SHIP compared with Niigata Study, even after comprehensive risk factor adjustment. Only to a very small extent, differences between studies could be explained by the risk factors explored.