Risk scores based on modifiable factors have recently been developed for dementia. This study aims to estimate the cost-effectiveness of a potential preventive intervention program meant to lower the score related to increased dementia risk. Analyses were based on a Markov model adapted to Swedish circumstances. Risk score categories and risk probabilities were derived from the Cardiovascular Risk Factors, Aging and Incidence of Dementia (CAIDE) study in Finland. Figures of costs, utilities, and mortality were obtained from literature or databases. One-way sensitivity analysis and probabilistic sensitivity analysis were carried out to investigate the robustness of the model and to identify which model inputs had most impact on the results. In the base case, the usual care had a cost of 621,000 SEK and utilities of 11.8438 quality-adjusted life year (QALYs). The intervention had a cost of 599, 026 SEK and utilities of 11.8950 QALYs. The cost was 21,974 SEK lower in the intervention with 0.0511 QALYs gained over a 20 years horizon, indicating absolute dominance. The support for cost-effectiveness was insensitive to changes in the value of QALY for demented, mortality, and risk of dementia. If the intervention program was assumed to run every year, the incremental cost-effectiveness ratio did not show absolute dominance but was still under the willingness-to-pay level. The probabilistic sensitivity analysis indicated cost effectiveness in 67% of the samplings given a willingness-to-pay level of 600,000 SEK/year. This is a promising outlook for future research on preventive interventions in dementia, emphasizing the need of conducting multi-domain randomized trials.