A new study has found that living in poverty can shape the neurobiology of a developing child "in powerful ways", affecting children's behavior, health and how well they do later in life.
US researchers found what they called "a biology of misfortune" among adults who were poor as children, in particular if they lived in poverty before the age of five, the study presented at the annual meeting of the American Association for the Advancement of Science (AAAS) shows.
Early childhood is a"crucial time for establishing the brain architecture that shape's children's future cognitive, social and emotional well-being," the study says.
"Children growing up in a disadvantaged setting show disproportionate levels of reactivity to stress, and it shows at the level of hormonal studies, neurological brain imaging studies and at the level of epigenetic profiling," said Thomas Boyce, of the University of British Columbia.
The researchers studied data on more than 1,500 individuals born between 1968 and 1975 taken from a 40-year demographic study of US households that measured family income during every year of childhood, educational attainment, what level people reached in their careers, plus crime and health as adults.
They found "striking differences" in how the children's lives turned out as adults, depending on whether they were poor or comfortably well-off before the age of six.
"Compared to children whose families had incomes of at least twice the poverty line during their early childhood, poor children complete two fewer years of schooling, work 451 fewer hours per year, earn less than half as much," the study said.
They also received more than 800 dollars a year more in food stamps as adults, and were more than twice as likely to report poor overall health or high levels of psychological distress, the study said.
Poor children were also fatter than their more affluent counterparts, and were more likely to be overweight as adults.
And the litany of misfortunes continues, with poor males twice as likely to be arrested and poor women six times more likely than their more affluent age-group peers to have a child out of wedlock.
But "economic conditions in early childhood matter most for labor market success," Duncan said.
The study also found that it was possible to positively shape the futures of poor children, by giving the families of under-fives additional income.
This was associated later in life with significantly higher adult earnings and work hours, and less need for state aid in the form of food stamps, the study found.
"The analysis indicates that policy makers might do well to focus on situations involving deep and persistent poverty early in childhood," the study said.
According to the authors of the study, four million children in the United States lived in poverty in 2007.
Jack Shonkoff, a professor at Harvard University, said the study provided "an amazing opportunity to learn more about the biology of misfortune and that will help us to develop some new ideas and create new interventions that may be able to mitigate the impact of adversity."
But he ruled out a quick fix that would address the biological side of the problem.
"Understanding the biology helps inform new social strategies rather than being turned into a medical treatment," he said.