A pioneering study on the physiological effects of poverty in young children offers a clue to why such kids have poorer health and a shorter life than their richer counterparts.
The study was conducted at the Cornell University and involved 217 low- and middle-income white adolescents - at age 9 and then again at age 13 - in rural areas of upstate New York.
Through it the researchers tried to determine several key mechanisms that explain how low socio-economic status takes its toll on health.
The research evaluated the neuroendocrine and cardiovascular markers of stress regulatory systems by measuring overnight levels of a stress hormone (cortisol) and blood pressure reactivity.
They also measured recovery after an acute stressor (being asked unexpectedly to do mental math problems) in the kids.
The boffins assessed cumulative physical and social risk exposure by measuring crowding, noise and housing quality in conjunction with maternal and youth reports of family turmoil, youth separation from family and exposure to violence.
They found that the longer 13-year-olds have lived in poverty, the less efficient their bodies become in handling environmental demands.
'We think that these mechanisms may be related to the fact that children who grow up in poverty have a steeper life trajectory of premature health problems than other children, regardless of their socio-economic status in adulthood,' said Gary Evans, the Elizabeth Lee Vincent Professor of Human Ecology and professor of human development and of design and environmental analysis in Cornell's College of Human Ecology.
'These muted responses of stress regulatory mechanisms, which are part of the cardiovascular system, not only compromise the ability of the adolescents' bodies to respond to such stressors as noise, poor housing and family turmoil but also indicate they are suffering from more stress-induced physiological strain on their organs and tissues than other young people.
'People need to understand that not leveling the playing field when it comes to poverty costs everyone money,' Evans added. 'It's very costly to society that low-income children end up getting sick prematurely and die younger than other people.
'The study provides yet another piece of evidence that poverty and other chronic risk factors induce physiological changes that appear to be related to long-term health problems,' he said.
The research is published in the November issue of Psychological Science.