ORIGINAL ARTICLE Childhood Socioeconomic Status and Adult Brain Size: Childhood Socioeconomic Status Influences Adult Hippocampal Size Roger T. Staff, PhD, 1 Alison D. Murray, MB ChB (Hons), FRCP, FRCR, 2 Trevor S. Ahearn, PhD, 2 Nazahan Mustafa, BSc, 2 Helen C. Fox, PhD, 3 and Lawrence J. Whalley, MD, FRCP 3 Objective: To investigate in older adults without dementia the relationships between socioeconomic status (SES) in childhood and magnetic resonance imaging (MRI)-derived brain volume measures typical of brain aging and Alzheimer’s disease (AD). Methods: Using a cross-sectional and longitudinal observation approach, we invited volunteers without dementia, all born in 1936, and who were participants in the 1947 Scottish Mental Survey, for MR brain imaging; 249 of 320 (77%) agreed. We measured whole brain and hippocampal volumes and recorded childhood SES history, the number of years of education undertaken, and adult SES history. Mental ability at age 11 years was recorded in 1947 and was also available. Results: Analysis shows a significant association between childhood SES and hippocampal volume after adjusting for mental ability at age 11 years, adult SES, gender, and education. Interpretation: A significant association between childhood SES and hippocampal volumes in late life is consistent with the established neurodevelopmental findings that early life conditions have an effect on structural brain development. This remains detectable more than 50 years later. ANN NEUROL 2012;71:653–660 T he adult brain reflects the sum of diverse genetic and environmental influences. In order to understand the contribution of the environment to brain development, it is relevant to consider the timing of each environmental effect. Early environmental influences can impair brain growth, affect the potential for maturation during the de- velopment phase, and influence the cognitive effects of age-related neurodegeneration. 1 This point is emphasized by early life contributions to the capacity of the brain to withstand neurodegeneration (‘‘reserve’’); reserve is deter- mined by many early life factors such as education and childhood intelligence. 2 Advances in imaging provide accurate measure- ments of brain structures and show that diseases of early life are associated with differences in brain development. In some studies, diseases of childhood, such as epilepsy, are selectively associated with specific brain structures 3 in the medial temporal lobe. In addition, childhood adver- sity is associated with smaller anterior cingulate cortex and caudate volumes. 4 The structure of the adult brain is also associated with adverse childhood experience. 5,6 Tomalski and Johnson 7 suggest that childhood socioeco- nomic status (cSES) has substantial and enduring effects on structural and functional brain development. These authors propose that the effects of cSES are mediated by several factors including poor diet, low-quality parental care, an impoverished and understimulating environ- ment, and prenatal exposure to toxic substances. Adverse childhood experiences are also associated with adult psy- chiatric disorders and cognitive deficits. 8 The association View this article online at wileyonlinelibrary.com. DOI: 10.1002/ana.22631 Received May 19, 2011, and in revised form Aug 22, 2011. Accepted for publication Sep 2, 2011. Address correspondence to Dr Roger T. Staff, Nuclear Medicine, Aberdeen Royal Infirmary, NHS-Grampian, Foresterhill Aberdeen AB25 2ZD, United Kingdom. E-mail: r.staff@abdn.ac.uk From the 1 Aberdeen Royal Infirmary, NHS-Grampian, 2 Aberdeen Biomedical Imaging Centre, University of Aberdeen, and 3 Institute of Applied Health Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom. V C 2012 American Neurological Association 653