Dementia: Time trends and policy responses

Are Trends in Dementia Incidence Associated With Compression in Morbidity? Evidence From The Framingham Heart Study

Objectives

Several epidemiological studies suggest declining trends in dementia over the last three decades with both decreasing age-specific prevalence and incidence. There is limited data on whether this delayed clinical onset is accompanied by a shorter postdiagnosis survival.

Methods

A total of 5,205 participants from the Framingham Original and Offspring cohorts were studied. Four epochs were considered from 1977-1984 to 2004-2008. Gender and education adjusted 5-year mortality risks were estimated using delayed entry Cox models with the earliest epoch as reference category. Stratified analyses by sex, education, and age were undertaken. A nested case control study of 317 dementia cases and 317 controls matched on age, gender and epoch was initiated.

Results

In the whole sample, 5-year mortality risk has decreased with time, it was 33% lower in the last epoch compared to the earliest. In the 317 persons who developed dementia, age at onset increased (1.5 years/epoch), and years alive with dementia decreased (1 year/epoch) over time. We observed however, a decreased adjusted relative mortality risk (by 18%) in persons with dementia in 1986-1991 compared to 1977-1983 and no significant change from then to the latest epoch. The nested case control study suggested in matched controls that 5-year mortality relative risk had increased by 60% in the last epoch compared to Epoch 1.

Discussion

In the FHS, in the last 30 years, disease duration in persons with dementia has decreased. However, age-adjusted mortality risk has slightly decreased after 1977-1983. Consequences of such trends on dementia prevalence should be investigated.

Incidence and Risk Profile of Dementia in the Regions of Middle East and North Africa

BACKGROUND

The risk of dementia is reported as "epidemic" and "looming" over the Middle East and North Africa (MENA) region. For this, we performed a multi-language review and feasible analysis on the incidence of dementia to offer apt conclusions.

METHODS

Totally, 3 databases (Magiran, Scientific Information Database, and PubMed) and 1 non-database source (Google) were searched in French, English, and Persian by using specific keywords and their combinations. All searches were independent and had no restriction for the year or type of publication. We also calculated cumulative incidence of dementia for Egypt and Israel-Palestine from relevant prevalence estimates by using standard formula.

RESULTS

Little information on incidence was available, sparing Israel (2.4/100,000/year; pre-senile). Ten (48.0%) countries had none-to-little information (of any kind) on dementia, indicating considerable awareness deficit in this region. Cumulative incidence of dementia in Egypt and Israel-Palestine was 2.7% over 20 years (55 new cases) and 14.7% (130 new cases) over 6 years, respectively. In Lebanon, cumulative incidence was 7.5% over 20 years. Data looked across dementia-related factors (i.e., fertility rate, polygamy, violence, hypovitaminosis D, diabetes, hypertension, life expectancy, age structure) did not seem to support epidemic proportions of dementia for MENA.

CONCLUSIONS

MENA is youthful and dementia here is neither likely to be an epidemic nor looming over. The only possible exception might be Arab pocket in Israel. To us, previous attributions on dementia do not seem to be based on the realities of this region and, therefore, may prevent pragmatic addressal of dementia. Lastly, values-based collaborations are invited to jointly fill the awareness deficit in a unique low-cost manner.

Simultaneous temporal trends in dementia incidence and prevalence, 2005-2013: a population-based retrospective cohort study in Saskatchewan, Canada

BACKGROUND

Original studies published over the last decade regarding time trends in dementia report mixed results. The aims of the present study were to use linked administrative health data for the province of Saskatchewan for the period 2005/2006 to 2012/2013 to: (1) examine simultaneous temporal trends in annual age- and sex-specific dementia incidence and prevalence among individuals aged 45 and older, and (2) stratify the changes in incidence over time by database of identification.

METHODS

Using a population-based retrospective cohort study design, data were extracted from seven provincial administrative health databases linked by a unique anonymized identification number. Individuals 45 years and older at first identification of dementia between April 1, 2005 and March 31, 2013 were included, based on case definition criteria met within any one of four administrative health databases (hospital, physician, prescription drug, and long-term care).

RESULTS

Between 2005/2006 and 2012/2013, the 12-month age-standardized incidence rate of dementia declined significantly by 11.07% and the 12-month age-standardized prevalence increased significantly by 30.54%. The number of incident cases decreased from 3,389 to 3,270 and the number of prevalent cases increased from 8,795 to 13,012. Incidence rate reductions were observed in every database of identification.

CONCLUSIONS

We observed a simultaneous trend of decreasing incidence and increasing prevalence of dementia over a relatively short 8-year time period from 2005/2006 to 2012/2013. These trends indicate that the average survival time of dementia is lengthening. Continued observation of these time trends is warranted given the short study period.

Prevalence and incidence of dementia among indigenous populations: a systematic review

BACKGROUND

Indigenous populations may be at increased risk, compared with majority populations, for the development of dementia due to lower education levels and socio-economic status, higher rates of diabetes, hypertension, cardiovascular disease and alcohol abuse, an aging population structure, and poorer overall health. This is the first systematic review investigating the prevalence and incidence of dementia in indigenous populations worldwide.

METHODS

This systematic review was conducted in accordance with PRISMA guidelines. We searched MEDLINE, Embase, and PsycInfo for relevant papers published up to April 2015. Studies were included if they reported prevalence or incidence, the disease typically occurred after the age of 45, the study population included indigenous people, and the study was conducted in the general population.

RESULTS

Fifteen studies representing five countries (Canada, Australia, the USA, Guam, Brazil) met the inclusion criteria. Dementia prevalence ranged from 0.5% to 20%. Retrospective studies relying on medical records for diagnoses had much lower prevalence rates and a higher risk of bias than population-based prospective studies performing their own diagnoses with culturally appropriate cognitive assessment methods.

CONCLUSIONS

The prevalence of dementia among indigenous populations appears to be higher than it is for non-indigenous populations. Despite a building body of evidence supporting the need for dementia research among indigenous populations, there is a paucity of epidemiological research, none of which is of high quality.