Caregiver burden and fatigue in caregivers of people with dementia: Measuring human herpesvirus (HHV)-6 and -7 DNA levels in saliva

• Salivary HHV-6 DNA levels of caregivers were higher than those of non-caregivers.
• Salivary HHV-6 DNA levels may be added as a new biomarker for exhaustion.
• The assessments of fatigue were useful to estimate caregiver burden.

PurposeWe examined chronic fatigue, which has not been investigated in detail, in family caregivers for people with dementia.Methods and materialsForty-four community-dwelling family caregivers (the caregiver group: CG) and 50 elderly control participants (the non-caregiver group: NCG) participated in this study. We measured salivary human herpesvirus (HHV)-6 and -7 DNA levels and the Chalder fatigue scale (CFS) to assess levels of fatigue; we also measured the Center for Epidemiologic Studies-Depression Scale, Physical Activity Scale for the Elderly, Zarit Caregiver Burden Interview, Mini-Mental State Examination, Assessment of Motor and Process Skills, and Dementia Behavior Disturbance Scale.ResultsFor CG, the salivary HHV-6 DNA levels and CFS scores were significantly higher than those in NCG. The salivary HHV-6 DNA levels in CG were significantly correlated with depressive symptoms, the cognitive function of the patients, and the activities of daily living/instrumental activities of daily living (ADL/IADL) abilities of the patients. The CFS scores in CG significantly correlated with caregiver burden, depression symptoms, leisure physical activity, the number of other family caregivers, and the hours spent for caregiving per week, as well as with behavior disturbances and ADL/IADL abilities.ConclusionsThe salivary HHV-6 DNA levels may be added as a new biomarker for caregiver exhaustion. We concluded that fatigue assessments should be performed by not only a questionnaire, such as the CFS, but also by a biomarker search, such as HHV-6, when estimating the caregiver burden for family caregivers of people with dementia.