Background Social care provision is increasingly important in the context of population ageing and the UK currently relies on family and friends to provide a majority of this care on an unpaid basis. Evidence regarding the health effects of providing unpaid care is mixed, possibly to a reliance on study designs which do not measure the temporality of events; few studies have examined changes in health around becoming a caregiver. Conflicting evidence may also reflect heterogeneity of effects by care characteristics (such as intensity) or caregiver characteristics (such as gender). Importantly from a life course perspective, when in the lifecourse people become caregivers is likely to influence its health effects. Most studies of caregiving and health have focused on mid-life or older caregivers, but younger adults also provide care, during a life stage which is crucial for establishing employment and family life. This study investigated the mental and physical health effects of becoming a caregiver and whether these associations varied by age of caregiving onset, gender, and caregiving intensity.

Data UK Household Longitudinal Study, a nationally representative household panel study, using annually-collected longitudinal data between 2009–2020.

Methods Mental health was measured using the 12-item General Health Questionnaire (GHQ-12) and the mental health component of the 12-item Short Form Survey (SF-12 MCS) while physical health was measured using the SF-12 physical component (PCS), all as continuous measures. We used propensity score matching to match participants who became caregivers to non-caregivers with similar characteristics. Sample sizes were n = 15,699 for GHQ-12 and n = 16,800 for SF-12. We modelled physical and mental health trajectories via piecewise growth curve modelling, centring the trajectories on caregiving transition. Predicted levels of mental and physical health with 95% confidence intervals are shown for every year up to eight years before and up to nine years after becoming a caregiver, comparing caregivers and matched non-caregivers. Models are shown, first pooled, then stratified by gender and weekly caregiving hours.

Results Mental health deteriorated for both measures in the year of becoming a caregiver, particularly for women under age 50. A deterioration in physical health in response to becoming a caregiver was only seen for those under age 30. Transitioning to intense caregiving (10+ hrs/week) was associated with a deterioration in both mental and physical health across all age groups.

Conclusion Our findings suggest support should be targeted to those providing intensive care and younger adult caregivers.