Dementia prevention research is crucial, given the expected increase in people with dementia. High blood pressure is one of the most important potentially modifiable risk factor for dementia. With qualitative and quantitative research I have studied the relation between blood pressure and dementia and how to best prevent this. We found that antihypertensive medication can prevent damage to the small cerebral vessels, but are not proven effective to prevent dementia. Certain classes of antihypertensive medication are associated with a lower risk of dementia. A lot of variation in blood pressure does not lead to a higher risk of dementia, but it is associated with a higher risk of cardiovascular disease. Dutch general practitioners are reluctant in starting and deprescribing antihypertensive medication in older patients. Finally, we have gotten to know more about the reasons for participation and motivation to keep participating in prevention research.