People with boring jobs have a higher risk of dementia according to researchers at University College London (UCL).
An investigation of seven large cohort studies suggests that people with mentally taxing jobs have a lower risk of dementia, as proteins which stop the brain cells forming new connections are linked to cognitive stimulation — processes called axonogenesis and synaptogenesis.
Cognitive stimulation at work was measured at the start of the study and participants were tracked for an average of 17 years.
After adjusting for other influential factors (sex, educaiton, lifetsyle) risk of demntia was lower for people with high stimulation at work. An incidence of 4.8 per 10,000 person years in the high stimulation group and 7.3 in the low stimulation group.
Lead author Professor Mika Kivimaki said that being mentally active is assumed to prevent the onset of dementia, but previous work on the topic has had varied results. While most long term studies suggest that cognitive activity during leisure time does not reduce risk of dementia.
Previous work-based studies had also failed to produce compelling evidence, Kivimaki said.
Her team looked at the seven large cohort studies, including over 100,000 participants, from the UK, Europe, and the US, to assess links between work related factors and chronic diseases, disability, and mortality.
"Our observational findings support the hypothesis that mental stimulation in adulthood may postpone the onset of dementia," said Kivimaki
“The levels of dementia at age 80 seen in people who experienced high levels of mental stimulation, was observed at age 78.3 in those who had experienced low mental stimulation.
“This suggests the average delay in disease onset is about one and half years, but there is probably considerable variation in the effect between people.”
The results were the same between men and women and for people younger and older than 60.
Mental stimulation was also linked to lower levels of three proteins linked to both cognitive stimulation in adulthood and dementia, providing possible clues to underlying biological mechanisms.
“The findings that cognitive stimulation is associated with lower levels of plasma proteins that potentially inhibit axonogenesis and synaptogenesis and increase the risk of dementia might provide clues to underlying biological mechanisms,” Professor Kivimaki added.Do you have an idea for a story?
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