Does telomere length mediate the association between early life adversity and mental health in childhood?

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BACKGROUND: Early-life adversity (ELA) increases the likelihood of developing depression and anxiety. Telomere length, a marker of biological aging, tends to shorten in response to oxidative stress and inflammation, which may play a role in the relationship between ELA and mental health. METHODS: Growing Up in New Zealand longitudinal study data was used to explore ELA, including parental, household, and environmental variables to determine whether child telomere length mediates associations between prenatal and postnatal adversity and offspring mental health (n = 3117, 47.7 % female). ELA measures were collected during pregnancy and when children were nine-months and four years old. Seventeen possible adverse experiences were categorized as low (0-4), moderate (5-7), and high (8+). At age four years, telomere length was measured by qPCR with DNA extracted from saliva. At age eight, children self-reported depression and anxiety symptoms. RESULTS: ELA was positively associated with depression and anxiety symptoms and telomere length. There was a direct effect of ELA on depression (β = 0.25, 95 % CI [0.14-0.37]), anxiety (β = 0.22, 95 % CI [0.07-0.37]), and telomere length (β = 0.03, 95 % CI [0.002-0.067]). There was no direct effect of telomere length on depression (β = 0.09, 95 % CI [-0.04-0.21]) or anxiety (β = 0.08, 95 % CI [-0.09-0.24]) and telomere length did not mediate the adversity-psychosocial relationships. CONCLUSION: ELA influences children's mental well-being and telomere length. Surprisingly, telomere length was longer following ELA, which may be a compensatory mechanism to regulate the effects of accelerated telomere attrition in response to adversity. Further research is needed to understand these complex and dynamic relationships across the life-course.