State care in childhood and adult mortality: a systematic review and meta-analysis of prospective cohort studies

Abstract

Background: Removal from family of origin to state care can be a highly challenging childhood experience and is itself linked to an array of unfavourable outcomes in adult life. We aim to synthetise evidence on the risk of adult mortality in people with a history of state care in early life, and assess the association according to different contexts.

Methods: In this systematic review and meta-analysis, we focused on four health outcomes hypothesised to be associated with exposure to early state care: total mortality, cardiovascular disease, cancer, and suicide. We searched the electronic databases PubMed and Embase from inception to Jan 21, 2022, for studies fulfilling the following criteria: it was a prospective study in which the assessment of care was made up to 18 years of age; it included an unexposed comparator group; the focus of the study was temporary out-of-home care and not adoption; mortality surveillance was extended into adulthood; standard estimates of association (eg, relative risk, odds ratios, or hazard ratios) and variance (eg, CIs and SE) were provided; the study appeared in a peer-reviewed journal; and the study was published in English. An adapted Cochrane Risk of Bias Tool was used to assess study quality. We extracted estimates of association and variance from qualifying studies and augmented these findings with analyses of unpublished data from individual participants in two UK birth cohorts-ie, the 1958 and 1970 studies (total n=21 936). We computed hazard ratios with accompanying 95% CIs for care and each health outcome separately for each study, and then pooled the results using a random-effects meta-analysis. This review is registered at PROSPERO, CRD42021254665.

Findings: We identified 210 potentially eligible published articles, of which 14 met our inclusion criteria (two studies were unpublished). Of 3 223 580 individuals drawn from 13 studies, those who were exposed to care in childhood had twice the risk of total mortality in adulthood relative to those without a history of care in childhood (summary risk ratio 2·21 [95% CI 1·62-3·02]), with study-specific estimates varying between 1·04 and 5·77 (I² =98%). Despite some attenuation, this association remained following adjustment for other measures of early-life adversity; extended into middle and older age; was stronger in higher-quality studies; and was of equal magnitude according to sex, geographical region, and birth year. There was some suggestion of sensitive periods of exposure to care, whereby individuals who entered state care for the first time in adolescence (2·47 [0·98-6·52]) had greater rates of mortality than those doing so early in the life course (1·75 [1·25-2·45]). In four studies including 534 890 people, children in care had more than three times the risk of completed suicide in adulthood relative to their unexposed peers (3·35 [2·41-4·68]), with study-specific estimates ranging between 2·42 and 5·85 (I²=72%). The magnitude of this association was weaker after adjustment for multiple covariates; in men than in women; and in lower-quality studies.

Interpretation: Our results for adult mortality suggest child protection systems, social policy, and health services following care graduation are insufficient to mitigate the adverse experiences that might have preceded placement into care and those that might accompany it.

Funding: None.