This study evaluated whether a nurse-led lifestyle modification program combined with cognitive play-based training could reduce dementia risk among older adults living in residential care homes. A total of 134 older adults from seven residential care homes in Cairo, Egypt, participated in the study. Participants received either the multidomain nursing intervention or usual care. The intervention included education on brain-healthy lifestyle behaviors and cognitive play activities designed to improve cognitive health and reduce modifiable dementia risk factors. The study assessed dementia awareness, dementia risk using the Lifestyle for Brain Health Risk Assessment (LIBRA), cognitive function, nutritional status, depression, and physiological and anthropometric measures. The findings showed that participants who received the intervention had greater dementia awareness, lower dementia risk scores, and better cognitive screening outcomes than those receiving usual care, supporting the effectiveness of multidomain nurse-led interventions for dementia prevention.