With the accelerated ageing of the population, dementia has become one of the biggest global health problems and a major disease burden and public health challenge for all countries,1 and it is expected to affect 153 million people worldwide by 2050.2 Dementia is a chronic degenerative disease that is typically characterized by cognitive impairment.3 There is no cure for dementia, and traditional medication only controls symptoms and has serious side effects.4 Therefore, dementia prevention has become a public health priority worldwide. The Lancet Commission noted that the incidence of dementia may be reduced up to 45% by controlling 14 modifiable risk factors.5 These risk factors include less education, hearing loss, hypertension, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption, traumatic brain injury, air pollution, social isolation, high LDL cholesterol, and vision loss. Targeting these factors collectively could significantly reduce dementia incidence by promoting lifestyle changes (e.g., cardiovascular health management), social engagement, and environmental improvements.5 This recommendation led to a proliferation of secondary prevention studies for patients at early clinical stages of dementia disorders (e.g., mild cognitive impairment or subjective cognitive impairment).6,7 In contrast, primary prevention based on populations at risk for dementia has been sorely overlooked.8 Family caregivers of people with dementia are one of the typically neglected at-risk groups, despite being very easy to track and target for precise dementia prevention.9

Family caregivers of people with dementia include family members (e.g., adult children or spouses) who have assumed caregiving responsibility. The home is the preferred place of care for people with dementia because this care reduces costs, fully respects the patient’s preferences and ensures their quality of life.10 However, the negative effects of lengthy and complex home care may lead to severe health risks for caregivers,11 with a high dementia risk being particularly prominent.12 For example, long-term chronic fatigue,13 sleep disorders,14 social isolation,15 and depression16 are highly prevalent among family caregivers, and these factors are important predictors of cognitive decline and dementia later in life.17 The risk of having dementia is influenced by a combination of genetic, lifestyle and environmental factors.18,19 Family caregivers cohabiting with dementia patients have likely been exposed to the same dementia risk factors as the patient. Simultaneous exposure to multiple dementia risk factors increases the susceptibility of family caregivers to cognitive decline and dementia with an earlier age of onset.20,21 Notably, the health risks of family caregivers directly affect patients' quality of life, and the stability and long-term development of the entire family system.22

Family caregivers of people with dementia also have unique characteristics. Unlike the general high-risk population, family caregivers have constructed highly individualized dementia cognitive systems during intimate caregiving.23 These caregivers tend to have more in-depth knowledge of dementia and a stronger perception of the susceptibility, severity, benefits, and barriers to dementia.24,25 The perceived threat of dementia in these individuals consistently influences the actions they may take for their own health. Family caregivers of people with dementia are vulnerable to preconceived stigma, discrimination and moral constraints of traditional culture,26,27 which may make it difficult to achieve positive health outcomes in their personal care and dementia prevention.28

Most previous systematic reviews on family caregivers of people with dementia focused on patient caregiving needs assessments, stress management, and caregiver burden.29,30,31 Although these studies reduced the caregiving burden of caregivers or benefited their physical and mental health to some extent,32 they failed to focus on the attitudes and perspectives of caregivers that spontaneously emerged during close contact and long-term interaction with the person with dementia. Only one systematic review examined the knowledge and perceptions of dementia care from the perspective of caregivers.33 However, that study did not consider family caregivers to be a high-risk group for dementia or further investigate their views and behaviors related to dementia prevention in the context of their unique illness perceptions. According to the Health Belief Model (HBM),34 these perception-based thoughts and cues to action (e.g., family member's disease shock, and sociocultural context) are keys to further guide family caregivers in initiating subsequent behavior.35

Because of the inherent complexity and uniqueness of family caregivers of people with dementia, we performed a mixed–methods systematic review under the guidance of the HBM.