The growth rate of young-onset dementia (YOD) is now significantly outpacing that of late-onset dementia (LOD) in China, according to a recent study published in The Journal of Prevention of Alzheimer's Disease.

The research, which analyzed data from the Global Burden of Disease study from 1990 to 2021, provides a systematic comparison of the burden characteristics between YOD, defined as onset before age 65, and LOD, which occurs at or after 65.

It shows that although the total number of LOD cases remains higher, the growth rate of YOD has surpassed that of the former since 2012. Key indicators, including incidence and prevalence, rose more sharply in the younger cohort from 2012 to 2021.

This is a critical public health alert, and dementia prevention must start at age 40 or earlier, according to Han Ying, a leading cognitive disorders specialist at Xuanwu Hospital in Beijing. Many people at the peak of their careers and family responsibilities are unknowingly at risk, and symptoms in younger adults are frequently missed.

The study also pinpointed that the main drivers of the increasing YOD burden shifted from population growth to epidemiological changes and population aging. In contrast, population growth remained the dominant driver for LOD.

The research identified three major modifiable risk factors for both YOD and LOD, namely tobacco use, high fasting plasma glucose, and high body mass index (BMI). Crucially, their impact differs significantly by sex.

For men, tobacco use is the dominant threat, reflecting China's high male smoking rates. For women, however, high fasting plasma glucose and high BMI pose a greater relative risk, with research indicating women with diabetes experience more pronounced structural brain damage.

In response, Han urged individuals to intervene earlier by prioritizing brain health from midlife, tailoring strategies by sex, and adopting a healthy lifestyle.