05 Sep Dementia Incidence Rates May Be Declining
MedicalResearch.com Interview with:
Carol A. Derby, Ph.D.
Research Professor, The Saul R. Korey Department of Neurology
Research Professor, Department of Epidemiology & Population Health
Louis and Gertrude Feil Faculty Scholar in Neurology
Albert Einstein College of Medicine
Bronx, NY 10461
MedicalResearch.com: What is the background for this study?
Response: The population over the age of 85 is expected to triple in the coming decades, and with the aging of the population, the number of individuals living with dementia is projected to increase dramatically.
While dementia prevalence rates are driven by demographic shift to older ages, changes in dementia incidence- the rate at which new cases are diagnosed, would also impact the proportion of the population affected in the coming decades.
Recently, studies have suggested that dementia incidence rates may be declining in some populations, although the results have not been consistent. Better understanding trends in dementia rates is important for public health planning.
Our objective was to determine whether there has been a change in the incidence of dementia diagnosis within a community residing group of over older adults followed by the Einstein Aging Study, at the Albert Einstein College of Medicine, in the Bronx, NY between the years 1993 and 2015.
To accurately characterize trends over time in disease rates requires separating the effects of age and the effects of calendar time. Therefore, we conducted a birth cohort analysis in which we examined age specific dementia incidence rates by birth year, for individuals born between 1910 and 1940. The analysis included over 1300 individuals over the age of 70, who were free of dementia when they enrolled in the study. Dementia was diagnosed using identical criteria over the entire study period, and study recruitment was also consistent over the period. We also examined trends in cardiovascular co-morbidities that have been related to dementia risk, as well as trends in education.
MedicalResearch.com: What are the main findings?
Response: We found that within each age group dementia incidence rates declined significantly for individuals born after 1929.
Prior research suggests that cardiovascular disease and diabetes are linked to dementia onset. Thus we examined the prevalence of myocardial infarction, stroke and diabetes by birth cohort.
We found trends consistent with national trends showing declining rates of myocardial infarction and stroke and increasing rates of diabetes for individuals born in more recent birth cohorts.
We also observed an increase in the level of education for those in the more recent birth years.
However, our analyses showed that the observed decline in dementia incidence was not fully explained by these trends in education or cardiovascular co-morbidities.
MedicalResearch.com: What should readers take away from your report?
Response: Our findings are consistent with findings from recent studies that suggest dementia incidence rates may be declining. Whether declining incidence will offset the demographic shift toward older ages remains to be seen. Further, given the increasing rates of diabetes in the population and research suggesting that diabetes increases dementia risk, our results highlight the need for continuing prevention efforts.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Future studies are needed to replicate our results in other populations. Continued prevention efforts may be needed to maintain the favorable trends, particularly those targeting the epidemic of diabetes in the general population.
Disclosures: This work was supported by a research grant from the National Institutes of Health, National Institute on Aging. (NIA AGO3949).
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Derby CA, Katz MJ, Lipton RB, Hall CB. Trends in Dementia Incidence in a Birth Cohort Analysis of the Einstein Aging Study. JAMA Neurol. Published online September 05, 2017. doi:10.1001/jamaneurol.2017.1964
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