Adult mortality in children exposed to state care: systematic review and meta-analysis of prospective cohort studies
Authors: Batty G. David , Kivimäki Mika , Frank Philipp 
Published: September 2021

Background

Removal from family of origin to placement in state care is a highly challenging and increasingly prevalent childhood experience. The purpose of this report was to synthesise published and unpublished prospective evidence on adult mortality in people with a history of state care in early life.

Methods

For this systematic review and meta-analysis, we searched PubMed and Embase from their inception to May 31st2021, extracting standard estimates of association and variance from qualifying studies. We augmented these findings with analyses of unpublished individual-participant data from the 1958 and 1970 Birth Cohort Studies (total N = 21,936). Study-specific estimates were aggregated using random-effect meta-analysis. The Cochrane Risk of Bias Tool was used to assess study quality. This review is PROSPERO-registered (CRD42021254665).

Findings

We identified 209 potentially eligible published articles, of which 11 prospective cohort studies from the UK, Sweden, Finland, the USA, and Canada met the inclusion criteria (2 unpublished). In 2,273,998 individuals (10 studies), relative to those without a care history in childhood, those who were exposed had 2.5 times the risk of total mortality in adulthood (summary rate ratio; 95% confidence interval: 2.58; 1.96 to 3.39), study-specific estimates varying between 1.53 and 5.77 (I2=92%). Despite some attenuation, this association held 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 and geographical region. There was a suggestion of sensitive periods of exposure to care, whereby individuals who entered public care for the first time in adolescence (3.54; 2.00 to 6.29) experienced greater rates of total mortality than those doing so earlier in the life course (1.69; 1.35 to 2.12). In five studies capturing 1,524,761 individuals (5 studies), children in care had more than three times the risk of competed suicide in adulthood (3.37; 2.64 to 4.30) with study-specific estimates ranging between 2.42 and 5.85 (I2=68%). The magnitude of this relationship was weaker after adjustment for multiple covariates; in men versus women; and in lower quality studies.

Interpretation

The excess rates of total and suicide mortality in children exposed to state care suggest child protection systems and social policy following care graduation are insufficient to mitigate the effects of the adverse experiences of care itself and the social disadvantage that preceded it.

Funding

None.

Research in context

Evidence before this study

Exposure to state care during childhood has emerging links with an array of unfavourable social, psychological, and behavioural characteristics in early adulthood. We searched PubMed and Embase from their inception to May 31st2021 for studies examining whether care is also related to elevated rates of adult mortality. While we identified a series of relevant studies, there was no synthesis of this evidence. Few studies utilised a prospective design such that the assessment of care was made in childhood, so avoiding biases of distant retrospective recall. There was also a lack of clarity regarding: the role of confounding factors; the influence of the timing of care entry on mortality; whether the impact of care extended into middle-age and beyond; and, as has been hypothesised, if men with a care history have a greater vulnerability than women.

Added value of this study

We conducted a systematic review to synthesis evidence on adult mortality risk in children placed in state care. Drawing also on unpublished resources to complement the findings of published studies, a total of 10 studies consistently showed that exposure to state care in childhood was associated with more than a doubling in the risk of total mortality. This association, while attenuated, held following statistical adjustment for other early life risk factors, including other adversities; extended into later adulthood such that it did not exclusively occur immediately following graduation from care; was stronger in better designed studies; and was of equal magnitude in men and women. There was also a suggestion of sensitive periods of exposure to care, whereby individuals who entered public care for the first time in adolescence experienced greater rates of total mortality in adulthood than those doing so earlier in the life course. The magnitude of the association between childhood care and adult risk of completed suicide (5 studies) were somewhat higher than for total mortality. This relationship was not completely explained by control for other early life risk factors; and the magnitude was somewhat weaker in lower quality studies, and in men versus women. There were too few studies to explore the impact of care on other causes of mortality.

Implications of all the available evidence

In recent years there has been a secular rise in the prevalence of children in state care in western societies. This excess mortality risk in this group did not appear to be attributable to other measures of adversity, suggesting that, in the countries studied, child protection systems and social policy following care graduation are insufficient to mitigate the effects of the adverse experiences of care itself and the unfavourable events that preceded it.