Anthropometry of head circumference, limb length and dementia

Abstract

Recent research findings suggest that dementia in late life may have its origin in early life. Head circumference (HC) and limb length are recognized to be determined at least in part by factors operating in childhood and remain stable into late life; these measurements may, therefore, be valuable proxy markers for early life environment particularly, it appears, early life nutrition. In this chapter, we review the research evidence for relationships between specific attained anthropometric measures - HC, leg length (LL), arm span and height - and other markers of early life environment, followed by associations between these measures and cognitive outcomes in later life (cognitive impairment and dementia). Smaller HC has been found to be associated with adverse cognitive outcomes including dementia and has been assumed, in this respect, to be a marker of brain "reserve." However, shorter LL and arm span have also been found to be associated with dementia and cognitive impairment. Shorter standing height measured both in early/mid and late life has found to be associated with adverse cognitive outcomes including dementia; however, due to the impact of spinal curvature and kyphosis on trunk length that occur with advancing age, limb length is a more reliable indicator of earlier stature. Several studies have suggested that associations between anthropometric measures and cognitive outcomes are modified by gender or apolipoprotein E genotype. Overall, for the prediction of disorders such as dementia, HC and limb length provide potentially important proxy information on childhood environment and are very cheap, easy, and quick to measure in epidemiological research.