Dementia Risk Lower for People in Challenging Jobs, Study Finds | Dementia

While cognitive stimulation is already believed to prevent or delay the onset of dementia, until now trials have been based on fairly small samples and short-term interventions, producing inconsistent results, the researchers said.

They suggested that a possible explanation for the conclusion of this large study is that cognitive stimulation is associated with lower levels of certain proteins that can inhibit certain processes in the brain.

Cognitive stimulation at work was measured at the start of the study and those involved were followed for an average of 17 years to see if they developed dementia.

The researchers said that cognitively stimulating jobs include demanding tasks and high decision latitude, also known as job control, while occupations considered non-stimulating are those with low demands and a lack of skill. work control.

They said that such exposure to cognitive stimulation at work can span decades and total tens of thousands of hours, that it lasts “considerably longer” than cognitive interventions or stimulating hobbies on the job. the cognitive level.

They found that the incidence of dementia was 4.8 per 10,000 people in the high stimulation group and 7.3 in the low stimulation group, after accounting for potentially influencing factors such as age, sex, level of education and lifestyle.

They made further adjustments for a range of dementia risk factors established in childhood and adulthood, and said the result remained the same.

There was no difference between genders or people over 60 or younger, but there was an indication that the association was stronger for Alzheimer’s disease than for other dementias.

The researchers acknowledged that the study is observational and therefore cannot establish the cause, but said the main strength of the work was the large sample size.

The study concluded: “This multi-cohort study of over 100,000 participants suggests that people with cognitively stimulating jobs have a lower risk of dementia in old age than those with non-stimulating jobs.”

Lead author Professor Mika Kivimäki of the Institute of Epidemiology at University College London and Health Care said: “Our results support the hypothesis that mental stimulation in adulthood may delay the onset of dementia.

“The levels of dementia at age 80 seen in people with high levels of mental stimulation were observed at age 78.3 in those with low mental stimulation. This suggests that the average time to onset of the disease is around a year and a half, but there is likely considerable variation in the effect between people. “

Dr Sara Imarisio, head of research at Alzheimer’s Research UK, said: “This large and robust study adds to a body of evidence suggesting that staying mentally active is important in helping to reduce the risk of dementia.

“Previous research has suggested that keeping the brain active can help build cognitive reserve, a type of resilience that helps the brain to ‘rewire’ its connections more easily and continue to function for longer when illnesses such as Alzheimer’s disease. Alzheimer’s are taking hold.

“This new research has also identified proteins in people’s blood plasma that may be linked to this process, and further research should study this finding in more detail.

“Not everyone can choose the type of work they do, but studies like this highlight the importance of finding activities that help keep the brain active, whether through work. or recreation. “