Growing up in poverty, growing old in frailty: the life course shaping of health in the United States, England and Europe-a prospective and retrospective study.

Childhood poverty is directly associated with many health outcomes in late life irrespective of youth health and of health system variation. The childhood poor in the United States (U.S.), England and Europe have reported worse cognitive, muscle and mental functions in their fifties to nineties. But it is not known whether they have higher probabilities of experiencing frailty as their childhood recollections are likely to be erroneous. Nearly 80,000 adults aged 50 and older retrospectively recalled their childhood conditions around ten and underwent prospective examinations to construct their Fried's frailty phenotype. Childhood conditions in England and Europe included number of books, number of rooms, number of people, presence of running hot or cold water, fixed bath, indoor lavatory and central heating (English Longitudinal Study of Ageing; Survey of Health, Ageing and Retirement in Europe). In the U.S., these were mostly replaced with financial hardship indicators including having to move because of family debt (Health and Retirement Study). Childhood poverty is a latent construct of error-laced recollection and its distal association with frailty phenotype was estimated with a fixed effects probit model. Sensitivity analyses were conducted using a random effects model and stratifying on sex. Childhood poverty associates with higher probabilities of being frail (0.1097 ± 0.0169, p < 0.001) in 29 countries including U.S., England and Europe. Furthermore, women have higher probabilities of being frail (0.3051 ± 0.0152, p < 0.001). Age, education, wealth, marital status and youth illness exert influences on the probabilities of being frail. Evidence is mounting that childhood can last a life time, affecting cognitive muscle and mental functions, and now frailty. This evidence calls for urgent actions to eliminate child poverty on account of its lifelong rewards.