DURHAM, N.C. - Children who grow up in poverty are more likely than wealthier children to smoke cigarettes, but they are less likely to binge drink and are no more prone to use marijuana, according to researchers at Duke Medicine.
The researchers also found that economic strains in early life - including family worries about paying bills or needing to sell possessions for cash - independently erode a child's self-control, regardless of strong parenting in adolescence. Lack of self-control often leads to substance use.
The findings, appearing July 30, 2013, in the Journal of Pediatric Psychology, debunk common assumptions about who abuses substances, and provide a basis for better approaches to prevent young people from falling into drug and alcohol addiction.
"Poverty during childhood not only appears to affect child development, but can have lasting effects on the types of health choices made during adolescence and early adulthood, especially as it relates to cigarette smoking," said senior author Bernard Fuemmeler, Ph.D., MPH, MS, associate professor in Community and Family Medicine at Duke University School of Medicine. "Economic strains may shape an individual's capacity for self-control by diminishing opportunities for self-regulation, or affecting important brain structures."
Fuemmeler and colleagues at Duke set out to examine the direct effect of childhood economic strains on smoking, binge drinking, and marijuana use in young adults. They also sought to determine how financial difficulties impact self-control, and how positive parenting might mitigate the tendency to use drugs and alcohol.
The group analyzed data from 1,285 children and caregivers included in a representative sample of U.S. families studied from 1986-2009. Economic status was measured by annual family income, plus a survey with questions about economic problems such as difficulty paying bills or postponing medical care. Additional information was gathered to gauge childhood self-control and parental interactions.
Among the study participants who were transitioning to adulthood, young people who lived in poverty as children were far more likely to become regular cigarette smokers than children who grew up in wealthier households. The impoverished children also scored low on self-control measures.
"Poor self-control may be a product of limited learning resources and opportunities for developing appropriate behaviors," Fuemmeler said.
Binge drinking, however, was much more common among the wealthier young people. And surprisingly, those who had good self-control as children were more likely to engage in heavy episodic drinking as young adults.
Neither wealth nor poverty appeared to influence marijuana use, although positive parenting did reduce the use of this drug. Parents who were nurturing and accepting, in fact, diminished the likelihood of young people using any of the substances.
The researchers also found no correlation between economic hardship and poor parenting - a contradiction to some other studies.
"We suspected we'd find a relationship between parenting and economic problems - the idea that economic strains may cause parents to have less capacity to deal with their children, but that relationship wasn't there," Fuemmeler said. "That means it's not necessarily poverty that affects the parenting strategy, but poverty that affects the children's self-control."
Fuemmeler said the findings are important given the increase in U.S. children living in poverty. The U.S. Census Bureau reported 22 percent of children lived in poverty in 2010, compared to 18 percent in 2000.
"Continued work is needed to better understand how economic strains may influence the development of self-control, as well as to identify other potential mediators between economic strains and substance use outcomes," Fuemmeler said.
In addition to Fuemmeler, study authors include Chien-Ti Lee, Joseph McClernon, Scott H. Kollins and Kevin Prybol.
The National Institutes of Health (RO1 DA030487), the National Cancer Institute (K07CA124905) and the National Institute on Drug Abuse (K24DA023464) funded the study.