Worldwide Patterns in Alzheimer’s Disease and other Dementias Prevalence from 1990 to 2017: A Growth Mixture Models Approach

Background: This study was designed to monitor the longitudinal trends of Alzheimer’s disease and other dementias (ADD) prevalence among world countries, as well as classifying them into clusters in which countries within each cluster have similar trends over time. Methods: The ADD prevalence in 195 countries during 1990–2017 were extracted from the Global Burden of Disease study’s database. The Latent Growth Models (LGMs) and also Latent Growth Mixture models (LGMM) were applied for trend analysis. Results: The highest and the lowest increase in ADD were observed in Europe and Africa, respectively. Increase in ADD was higher in women. LGMM allocated Nordic Countries in the class with a downward trend with a downward trend, with rate of -11.5 in 100000 person in every 2 years. Japan alone entered a class with a dramatically sharp increase with rate of 185 in 100000 person in every 2 years, the highest rank in ADD trend. Most European and American countries were entered into classes with higher increasing trend, rate between 20.4 and 53.6 in 100000 person in every 2 years, relative to the most of Asian countries which were less likely to have the increase of ADD, with rate of 6.45 in 100000 person in every 2 years. Conclusion: A substantial difference was observed in ADD trend among the countries: the decline in Nordic countries, which could be due to "Health Care of the elderly in the Nordic Countries" program, and the highly differentiated ascending trend in Japan, which is not necessarily due to the aging population; none of other countries, which have elderly population too, witnessed such sharp increase in their ADD. The clarification of the cause of the last finding calls for more epidemiological studies.