Impact of caregiving for older people and pro-inflammatory biomarkers among caregivers: a systematic review.

INTRODUCTION: Evidence suggests that providing care for an older loved one may present a risk to the health of the caregiver. To understand the link between the psychosocial stress of caregiving and damage to the health of caregivers, numerous studies have assessed the presence of inflammatory biomarkers among caregivers. These biomarkers are measured to understand the relationships between the social stress of caregiving and the health of caregivers.

OBJECTIVE: To provide a complete summary of the current literature regarding the most clinically relevant pro-inflammatory biomarkers associated with caregiving.

METHODS: We searched articles in MEDLINE and EMBASE from January 1980 to 30 April 2016 for all studies that assessed biomarkers (cortisol, interleukin-6 and c-reactive protein) among caregivers of community-dwelling older persons. The quality of the selected studies was assessed by two reviewers using the STROBE or CONSORT checklist.

RESULTS: Twenty-four studies were included. Most of the studies were cross-sectional and focused on dementia caregiving. Increases in biomarkers were associated with problems such as disturbed sleep, burden or pain and caregiving characteristics, including daily stressors and the duration of caregiving. Cognitive-behavioural therapy and participation in leisure activities were associated with significantly lower levels of cortisol and IL-6, respectively.

DISCUSSION: We found little evidence concerning the association between caregiving status and biomarkers of stress and inflammation. We discuss potential sources of bias and suggest some directions for further research. This stress model can be expanded by taking into account the positive aspects of caregiving and the potential resources of caregivers.