Reading while sitting down may help reduce dementia risk: study

By Stephen Beech

Reading or doing a crossword while sitting down help reduce the risk of dementia, according to new research.

But couch potatoes who veg out in front of the telly for hours on end actually increase their chances of developing the long term condition, say scientists.

The findings come from a ground-breaking study showing that different forms of sitting down have vastly ranging impacts on dementia risk.

Researchers found that activating the brain while seated helps reduce the risk of dementia.

They say their findings, published in the American Journal of Preventive Medicine, provide valuable information for formulating future dementia prevention campaigns.

It was previously thought that all forms of seated, or sedentary, behavior were associated with a higher risk of developing dementia.

However, more recent studies found that "couch potato" mentally passive sedentary behaviors - such as watching telly - increase dementia risk.

But mentally active sedentary behavior - such as reading or office work - appeared to be protective.

Most adults spend between nine and 10 hours per day sitting.

Previous research has shown that extended, uninterrupted sitting is a risk factor for heart disease, type 2 diabetes, and depression. It has also been associated with dementia.

The new study is the first to distinguish between passive and mentally active sitting in association with dementia.

Researchers found that adults who engaged in extended durations of mentally passive sedentary behavior had a higher risk of dementia.

However, replacing passive with mentally active sedentary behavior was shown to reduce the risk of dementia onset in later life.

Dementia is the third highest cause of death and the seventh largest cause of disability among older adults worldwide.

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Lead investigator Professor Mats Hallgren, of the Karolinska Institute in Stockholm, Sweden said: “While all sitting involves minimal energy expenditure, it may be differentiated by the level of brain activity.

"How we use our brains while we are sitting appears to be a crucial determinant of future cognitive functioning and, as we have shown, may predict dementia onset.”

Researchers analysed data from a study involving more than 20,000 Swedish adults aged 35 to 64 who were followed over 19 years.

The initial survey included questions about sedentary behavior, physical activity, and other behaviors associated with dementia.

Dementia was identified by linking the data of the 1997 survey with the Swedish National Patient Register and the Swedish Cause of Death Register.

Using various statistical models, the research team examined the associations with dementia of, statistically, substituting passive with mentally active sedentary behaviors.

The findings showed that mentally active sedentary behavior was associated with a reduced risk of developing dementia among middle-aged and older adults.

Increasing time spent in mentally active sedentary behavior was associated with a "significant" reduction in dementia risk while maintaining the levels of passive sedentary behavior, light and moderate-to-vigorous physical activity.

Replacing the amount of time spent in mentally passive sedentary behavior for equivalent durations of mentally active sedentary behavior was also associated with a reduction in the risk for developing dementia.

Given the extensive survey method used to collect the data - including 3,600 cities and villages across Sweden, the research team believe the findings are likely generalisable to a wider global population.

Hallgren said: “The prospective study design allowed us to establish the direction of these relationships and infers but does not establish causality.

"Controlled trials are needed to confirm these important observational study findings."

Hallgren, who also holds a post at Deakin University in Australia, added: “Sedentary behavior is a ubiquitous but modifiable risk factor for many health conditions, including dementia.

"Our study adds the observation that not all sedentary behaviors are equivalent; some may increase the risk of dementia, while others may be protective.

"It is important to remain physically active as we age, but also mentally active - especially when we are sitting.”