The BBHI is a research project aimed at learning and understanding how to maintain brain health. The project follows approximately 5,500 participants aged between 40 and 65 years, free from any psychiatric or neurological major diagnoses made by their reference physicians at the time of recruitment. The participants are community-dwelling individuals, with a higher prevalence of women, highly educated, and with better lifestyles compared with the general population. Participants enrolled in the project through the web-based application and have completed follow-up questionnaires online.