Childhood Club Participation and All-Cause Mortality in Adulthood: A 65-Year Follow-Up Study of a Population-Representative Sample in Scotland

Childhood Social Isolation as a Predictor of Retinal Neuronal Thickness in Middle Age: A Lifecourse Birth Cohort Study

OBJECTIVE

We investigated whether childhood social isolation was associated with retinal neural layer changes in adulthood, and whether this association was independent of other childhood or adulthood risk factors, including adult social isolation.

METHODS

Participants were members of the Dunedin Multidisciplinary Health and Development Study, a longitudinal population-based birth cohort from Aotearoa New Zealand ( n = 1037), born 1972 to 1973 and followed until age 45 years, with 94% of the living cohort still participating. Social isolation was recorded prospectively at ages 5, 7, 9, and 11 years, from teacher and parent report. Retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer thicknesses were measured via optical coherence tomography at age 45 years.

RESULTS

Childhood social isolation was associated with thinner average RNFL ( B = -0.739, p = .02), nasal RNFL ( B = -1.118, p = .005), and inferior RNFL ( B = -1.524, p = .007), although only nasal RNFL remained significant after adjustment. These associations were not fully explained by other psychosocial or physical health risk factors in childhood or adulthood, nor were they mediated by adult loneliness or social support.

CONCLUSIONS

Childhood social isolation was an independent predictor of RNFL thickness in middle age. Highlighting prospective links between childhood psychosocial adversity and retinal neuronal measures will help to inform future research into the utility of retinal neuronal thickness as a biomarker for neurodegeneration.

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

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.

Social participation and 5-year all-cause mortality in older Chilean people

We aimed to examine the degree to which social participation is associated with mortality risk in older adults in Chile. We used the Chilean National Survey on Elderly Dependency, which is linked to vital statistics, in order to obtain death records. Four proportional risk regression models were estimated. Even with controlled sociodemographic, economic, family, and health variables, older adults who participate in social activities had a 22% lower risk of death than those who do not participate. We concluded that social participation is a strong and significant protective factor for mortality in Chilean older adults. Social participation should thus be promoted from a life course perspective considering its effect on mortality in older adults who maintained an active social life.

Intelligence and all-cause mortality in the 6-Day Sample of the Scottish Mental Survey 1947 and their siblings: testing the contribution of family background

Background

Higher early-life intelligence is associated with a reduced risk of mortality in adulthood, though this association is apparently hardly attenuated when accounting for early-life socio-economic status (SES). However, the use of proxy measures of SES means that residual confounding may underestimate this attenuation. In the present study, the potential confounding effect of early-life SES was instead accounted for by examining the intelligence-mortality association within families.

Methods

The association between early-life intelligence and mortality in adulthood was assessed in 727 members of the 6-Day Sample of the Scottish Mental Survey 1947 and, for the first time, 1580 of their younger siblings. These individuals were born between 1936 and 1958, and were followed up into later life, with deaths recorded up to 2015. Cox regression was used to estimate the relative risk of mortality associated with higher IQ scores after adjusting for shared family factors.

Results

A standard-deviation advantage in IQ score was associated with a significantly reduced mortality risk [hazard ratio = 0.76, p < 0.001, 95% confidence interval (CI) (0.68-0.84)]. This reduction in hazard was only slightly attenuated by adjusting for sex and shared family factors [hazard ratio = 0.79, p = 0.002, 95% CI (0.68-0.92)].

Conclusions

Although somewhat conservative, adjusting for all variance shared by a family avoids any potential residual confounding of the intelligence-mortality association arising from the use of proxy measures of early-life SES. The present study demonstrates that the longevity associated with higher early-life intelligence cannot be explained by early-life SES or within-family factors.

Reserve and Reserve-building activities research: key challenges and future directions

Background

The concept of Cognitive Reserve has great appeal and has led to an interesting and important body of research. We believe, however, that it is unnecessarily limited by ‘habits’ of measurement, nomenclature, and intra-disciplinary thinking.

Main body

A broader, more comprehensive way of conceptualizing Reserve is proposed that invokes a broader measurement approach, nomenclature that uses specific terms embedded in a theoretical model, and crosses disciplines.

Conclusion

Building on this comprehensive conceptualization, we will discuss fruitful directions for future research.