Early-life determinants of frailty: A comprehensive review
Frailty is a complex, aging-related clinical syndrome characterized by decreased reserves to stressors. Factors in early life are posited to have a long-term impact on health through separate and combined effects of biological, behavioral, and psychosocial mechanisms. There is a consensus that physical, behavioral, psychosocial, and environmental risk factors in early life play essential roles in developing frailty in old age. Over the past two decades, we have witnessed a proliferation of literature on early-life risk factors for frailty in developed and developing countries and areas. We summarized empirical studies examining how early-life risk factors contributed to the development of frailty. We classified risk factors into four dimensions: biological factors, socioeconomic circumstances, healthy lifestyles, and environmental exposures. We identified a wide range of biological (body size and intelligence), social (education, parental education, and socioeconomic conditions), lifestyle (childhood health status and nutritional status), and environmental factors (home environment, neighborhood quality, and traumatic wartime experience) associated with frailty in old age. Future research should adopt novel methodologies to address the complexity and interconnectedness of risk factors in distinct early-life stages, use more rigorous study designs and analytic tools to unravel the underlying mechanisms, and pay more attention to the transition and progression of frailty. This review highlights the enduring impact of early-life experiences on frailty and suggests the necessity of designing frailty interventions from a life course perspective. Interventions improving early-life circumstances might delay or even prevent the emergence of frailty in old age.
