Risk factors of dementia in a life-course perspective. Measures to overcome barriers to modification of health behaviour.

As there still is no cure for dementia, research has focused on measures to prevent or delay dementia. Several lifestyle risk factors for dementia have been identified, but whether these risk factors are most important in early life, midlife or in late-life remains to be understood. Furthermore, measures to modify health behaviour have, with a few exceptions, been unsuccessful. In this project, we will use data from one of the largest population-based studies in the world, the Health Survey in Trøndelag (HUNT). HUNT has been carried out fire times, with approximately 10-year intervals, from the 1980's. As part of the fourth HUNT study (HUNT4), a investigation of cognitive impairment and dementia in all participants 70 years of age and older where done. As nearly all modifiable risk factors for dementia have been assessed in HUNT1, HUNT2 and HUNT3, this gives us a unique opportunity to study how health behaviour and lifestyle risk factors up to 30 years prior to dementia debut impact the risk of getting dementia. We will focus particularly on how socioeconomic factors, such as education and working life are associated with the other risk factors. In the fall of 2021 and again in 2024, two comprehensive surveys will be conducted to determine the population's knowledge of dementia risk and willingness to alter their health behaviors. A random sample of 8000 people aged 40-70 from Oslo, Innlandet, Trøndelag, and Nordland was invited to participate in the survey by mail. The same questions that deal with knowledge about risk factors for dementia was also included in the questionnaire in Ageing in Trøndelag (AiT), where former HUNT4 70+ participants were invited again. AiT started on the 1st of September 2021, and ended in june 2023. During winter 2021/2022, qualitative interviews were performed to gain a deeper understanding of the norwegian peoples knowledge about dementia risk factors. During 2023 we have interviewed decision-makers in municipalities about the same topic. This will create knowledge that will help individuals and decision-makers to implement dementia prevention- and treatment measures. The data colllection in AiT was completed in June and the QA work is ongoing. We expect data to available for analysis in February 2024. Totally, 5731 participants were included in AiT, which is a participation rate of around 74%.

The present project focuses on the most common type of neurodegenerative disorders, dementia, and how these disorders may be prevented or postponed by lifestyle change. As the prevalence of dementia is increasing rapidly and there is no indication that curative treatment will be available soon, other ways to decrease the individual and societal burden of this disorder are sought for. Several lifestyle risk factors for dementia have been identified, but the timing of these risk factors is still poorly understood. One lifestyle factor may increase the risk in midlife and decrease it in late-life. Social inequalities may be associated with both dementia risk and lifestyle risk factors of dementia and may impact on willingness to change health behaviour. Knowledge about possible prevention of dementia is a prerequisite for willingness to change health behaviour. We will use the data from one of the largest population studies worldwide on health-related lifestyle, the HUNT study. It has been carried out four times, from the 80's to 2019. In 2017-19, 9200 participants 70 years or older participated in HUNT4 70+, where they were thoroughly examined for cognitive impairment or dementia. We will investigate how lifestyle factors 30, 20 and 10 years prior to HUNT4 70+ are associated with their current dementia risk. Furthermore, we will follow-up a subgroup of the HUNT4 70+ sample to study more specifically how the lifestyle risk manifest itself in late-life. To investigate knowledge about dementia risk prevention and willingness to change health behaviour we will carry out two national public surveys, one at the start and one at the end of the project period. To get deeper understanding of this topic we will interview the public individually and decision makers in groups, applying qualitative methods. Finally, we will gather all the project information and develop plans for health behaviour interventions that are feasible for the authorities and acceptable to the public.