A new study shows that variables linked to socioeconomic status (SES) – such as increased stress and decreased sleep – have strong relationships with brain structure and function in children.
“Although previous work has found that socioeconomics can influence brain structure and function, [these authors] demonstrate these effects with remarkable scale and consistency,” write Lucinda M. Sisk and Theodore D. Satterthwaite in a related perspective. Brain-wide association studies (BWAS) examine how variability in brain structure or function across many people is related to differences in behavior, mental health, or environmental exposures. Such studies often assess measures such as functional connectivity and brain variation over time.
Here you go, Scott Marek et al. sought to identify which exposures (out of 649 different variables) were most strongly associated with functional connectivity and cortical thickness in a sample of 9- to 10-year-olds from the Study of Adolescent Brain Development (ABCD).
The authors found that a combination of SES-related factors – such as family income and neighborhood opportunities – were most strongly associated with functional connectivity. Such SES-related differences in functional connectivity were most pronounced in brain regions involved in sensory and motor processing, where screen time and reduced sleep—both associated with lower socioeconomic status—showed stronger associations. Because these brain regions are associated with arousal, and because arousal acts as a regulator of brain activity, it is possible that stressors related to socioeconomic status can change arousal patterns over time, causing lasting differences in brain function, the authors say.
Marek and colleagues saw the same patterns when they replicated their study on a sample from the UK Biobank (95% white British, white Irish or other white background). Combined with analyzes stratified by genetic ancestry in the original youth sample, these findings suggest that brain differences associated with socioeconomic factors are unrelated to genetic ancestry, the authors say. Marek and colleagues note that “it remains unclear when strong associations between brain and SES first emerge or when environmental interventions may be most beneficial,” but “socioeconomic opportunity is not destiny.” Any patterns created during sensitive periods of development may not be permanent. Leading candidates for enhancing brain function and structure may be interventions related to sleep and chronic stress. The findings underscore the need for societal-level policies that provide early support to families, Sisk and Satterthwaite say in Perspective.
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