Young-onset dementia more prevalent than estimated previously: JAMA

Reliable prevalence estimates are lacking for young-onset dementia (YOD), in which symptoms of dementia start before the age of 65 years. Such estimates are needed for policymakers to organize appropriate health care.

A study was conducted by a group of researchers from the Netherlands to determine the global prevalence of young-onset dementia (YOD).

The researchers systematically searched databases like PubMed, Embase, CINAHL, and PsycInfo for population-based studies on the prevalence of young-onset dementia (YOD) published between January 1, 1990, and March 31, 2020.

Two researchers screened studies containing data on the prevalence of dementia in individuals younger than 65 years for inclusion in a systematic review and meta-analysis.

The main outcome of the study was Prevalence estimates of young-onset dementia (YOD) for 5-year age bands.

The results of the study are as follows:

• A total of 95 unique studies were included in this systematic review, of which 74 with 2 760 379 unique patients were also included in 5-year age band meta-analyses.
• Studies were mostly conducted in Europe and in older groups in Asia, North America, and Oceania.
• Age-standardized prevalence estimates increased from 1.1 per 100 000 population in the group aged 30 to 34 years to 77.4 per 100 000 population in the group aged 60 to 64 years.
• This gives an overall global age-standardized prevalence of 119.0 per 100 000 population in the age range of 30 to 64 years, corresponding to 3.9 million people aged 30 to 64 years living with YOD in the world.
• Subgroup analyses showed prevalence between men and women to be similar, whereas prevalence was lower in high-income countries compared with upper-middle-income and lower-middle-income countries.
• Meta-regression showed that age range sample size and study methodology significantly influenced heterogeneity between studies.

Thus, the researchers concluded that an age-standardized prevalence of YOD of 119.0 per 100 000 population, although estimates of the prevalence in low-income countries and younger age ranges remain scarce. These results should help policymakers organize sufficient health care for this subgroup of individuals with dementia.

Reference:

Global Prevalence of Young-Onset Dementia: A Systematic Review and Meta-analysis by Hendriks S et. al published in the JAMA Neurol

doi:10.1001/jamaneurol.2021.2161