模仿句子：Researchers say the number of people living with dementia in parts of Western Europe is stabilising which is a bit surprising because the incidence has been increasing as people live longer and that process continues. So what might be happening? 

翻译：研究人员指出，西欧部分地区的老年痴呆患者人数正趋于稳定。这是个奇怪的现象，因为随着人们寿命变长，又不断有人患上老年痴呆，发病率一直都在攀升。那么到底是怎么一回事呢？