Appropriate duration of sitting meditation can reduce the risk of dementia in the elderly!

Dementia , also known as "dementia", is a disease characterized by severe cognitive impairment. Common types include Alzheimer's disease and vascular dementia . As we all know, dementia has become one of the main "health killers" for the elderly. Its harm is not limited to the decline of cognitive functions such as memory, but also progresses to the inability to take care of oneself, and in severe cases even endangers the life safety of oneself and family members. Unfortunately, once dementia occurs, it is almost impossible to reverse and cure . It is estimated that by 2050, the number of people with dementia worldwide will increase to 152.8 million. Therefore, there is an urgent need to identify more modifiable risk factors for preventing the occurrence of dementia.

Meditation refers to low-energy behaviors such as sitting, reclining, or lying down for a long time while awake . As early as 2020, the World Health Organization proposed to reduce the duration of meditation. However, one reality we have to face is that meditation is a daily activity that we cannot completely avoid, and it is gradually occupying more and more of the daily time of the elderly. So, how long can we "sit"? How should we "sit"? To date, no further recommendations have been given.

Specifically, meditation includes many types, such as watching TV, using computers, driving, etc. Previous studies have found that different types of sedentary behaviors may not be exactly the same in their associations with health. However, the association between different sedentary behaviors and dementia and its subtypes, such as Alzheimer's disease and vascular dementia, is still unclear. In addition, we may have more than one type of sedentary behavior in our daily activities. Therefore, it is obviously inaccurate to consider the association between a certain type of sedentary behavior and dementia risk in isolation and singularity. At the same time, from the pathophysiology of the occurrence and development of dementia, inflammation and genetic risk play an important role, and sedentary behavior can also affect the level of inflammation in the body . However, it is not clear whether the level of inflammation and the genetic risk of dementia affect the relationship between meditation and dementia risk.

In response to the above issues, a recent study published in the medical journal Journal of the American Medical Directors Association found that the time spent watching TV, using computers (non-work) or driving each day showed a U-shaped or inverse J-shaped correlation with the risk of dementia in the elderly; when each sedentary behavior was controlled at 0-2 hours per day, the risk of dementia was significantly reduced. When the total sitting time remained unchanged, increasing the diversity of sedentary behaviors was associated with a significantly lower risk of dementia compared to a single sedentary behavior. Professor Qin Xianhui of the National Clinical Research Center for Kidney Diseases of Nanfang Hospital is the corresponding author of the article, and graduate student Yang Sisi is the first author.

The study included more than 170,000 elderly participants from the UK Biobank who did not have dementia at baseline. The healthy sedentary behavior score was defined as the number of sedentary behaviors that were within the appropriate range (i.e., the duration with the lowest risk of dementia) for watching TV, using a computer (non-work), and driving, with a total score of 0 to 3.

During 12.4 years of follow-up, 4965 participants developed all-cause dementia, 2165 developed Alzheimer's disease, and 1141 developed vascular dementia.

Research shows that:

(1) The duration of watching TV and driving was associated with the risk of new-onset all-cause dementia in a U-shaped manner, while the duration of (non-work) computer use was associated with the risk of new-onset all-cause dementia in an inverse J-shaped manner. Compared with participants with a daily sitting time of >0-<2 hours, participants who spent 0 hours/day watching TV, driving, or (non-work) computer use had a significantly increased risk of new-onset all-cause dementia by 29%, 41%, and 42%, respectively; participants who spent 2 hours/day watching TV, driving, or (non-work) computer use had a significantly increased risk of new-onset all-cause dementia by 22%, 33%, and 20%, respectively. Similar associations were observed in the analysis of Alzheimer's disease and vascular dementia (Figure 1).

Figure 1. Association of Different Types of Sedentary Behavior with the Risk of New-onset All-cause Dementia.

(2) For every 1 point increase in the healthy sedentary behavior score, the risk of all-cause dementia, Alzheimer's disease, and vascular dementia was significantly reduced by 22%, 22%, and 25%, respectively.

(3) Among participants with higher inflammation levels, healthy sedentary behavior scores had a stronger inverse association with dementia risk than among participants with lower inflammation levels (Figure 2, A).

(4) Regardless of the individual's genetic risk of dementia, healthy sedentary behavior scores were significantly negatively correlated with dementia risk (Figure 2, B).

Figure 2. Association between healthy sedentary behavior and dementia risk in participants with different levels of inflammation (A) and genetic risk (B).

The study shows that "sitting" is not terrible. A good rest is necessary anyway, but the duration must be controlled. For example, it should be reasonable within 0-2 hours. In addition to watching TV, it is better to chat online, read the news, and read books from time to time to increase the diversity of meditation types. In general, maintaining healthy and diverse sedentary behaviors and low inflammation levels "two-pronged approach" may be one of the very important strategies for preventing the risk of dementia in the elderly .

Seeing this, the editor would like to ask everyone: "To prevent Alzheimer's disease, do you know how to 'sit'?"

References:

Yang S, Ye Z, Liu M, et al. Variety and Duration of Different Sedentary Behaviors, Inflammation, Genetic Susceptibility, and New-Onset Dementia in the Older Population [published online ahead of print, 2023 Jul 11]. J Am Med Dir Assoc. 2023; S1525-8610(23)00551-0.

Editor | Yang Sisi Huang Yu

Audit | Qin Xianhui

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