Less dementia among occupational groups with cognitively demanding jobs
Research findings
|Published
A study from the Norwegian Institute of Public Health and Oslo University Hospital shows that people with cognitively demanding jobs during their 30s to 60s have a lower risk of mild cognitive impairment and dementia after 70 years of age than people with less cognitively demanding jobs.
14% of us will develop dementia by 70 years of age and roughly half of us will develop it by the age of 90 according to data from Norway (fhi.no, only in Norwegian). People with less cognitively demanding jobs, such as cleaners, have almost a 40% higher chance of developing dementia by age 70, as shown in this new study.
The study, published in the journal Neurology (link to journal article), assessed the impact of occupational cognitive demands on the risk of mild cognitive impairment and dementia among over 7000 participants in the HUNT4 70+ cohort (link to the HUNT study webpage) in Norway.
The study is an association study and does not provide any definitive information about the cause of dementia, as many factors are involved.
Boost your brain
The researchers divided the participants into four groups according to the amount of routine tasks in their occupations during their 30, 40s, 50s and 60s, and compared the risk of cognitive decline in these groups after the age of 70. The researchers also took into account other important risk factors of dementia, including age, sex, education, income, physical and mental health and lifestyle.
After adjusting for age, sex and education the researchers found that the group with more routine tasks in their occupations had a 37% higher risk of dementia after the age of 70. Furthermore, the findings underscore the impact of educational attainment on later life cognitive health.
"The results of this study underscore the potential of cognitively stimulating work to boost cognitive reserve and delay the onset of cognitive decline", says principal research Bjørn Heine Strand at the Norwegian Institute of Public Health.
"This study supports the “cognitive reserve hypothesis”, which basically states that the more you use your brain during early and mid-life, the better equipped you are to ward off dementia and cognitive decline later in life", says Strand.
FHI published a study last autumn that showed an increased risk of dementia among occupations with high levels of physical activity (fhi.no, in Norwegian only). This current study, on the other hand, deals with the effect of cognitive stimulation in working life. Although both studies deal with work-related factors, they measure completely different aspects of working life.
It’s never too late to learn
The main author of the study, Trine Holt Edwin from Oslo University Hospital, adds that this study emphasizes the importance of life-long learning and can inform decision-makers about the importance of education and cognitively stimulating work life for cognitive health in older age.
"This shows that it is never too late, or a waste of time, to start learning something new. All cognitively demanding activities later in life contribute to strengthening one’s cognitive reserve", says Edwin.
The results of this study also support other central studies in the field of dementia, including the 2020 report from the Lancet Commission (link to thelancet.com) on factors that prevent dementia.
Limitations of study
This is an association study and does not say anything definite about the cause of dementia. Many other factors play a part, as shown in other studies . The researchers did not differentiate between various types of cognitive demands within the same occupational category and did not account for changes in work tasks over time.
About the study
This study is part of a larger project called Changing lives, changing brains, lead by the Norwegian Institute of Public Health, Columbia University New York and the University of Pennsylvania. The study was conducted by researchers at the Norwegian Institute of Public Health, Oslo University Hospital, the Norwegian National Centre for Ageing and Health, HUNT Research Centre, Norwegian University of Science and Technology, Ragnar Frisch Center for Economic Research (Norway), Levanger Hospital Norway, University of Bergen (Norway), University of Oslo (Norway), University of Pennsylvania (USA) and Columbia University (USA).
For additional information on this study or to request an interview with the research team, please contact Duty Press Officer at the Norwegian Institute of Public Health at medievakt@fhi.no.
