Teens who were depressed as children are far more likely than their peers to be obese, smoke cigarettes and lead sedentary lives, even if they no longer suffer from depression, according to a study.
The research, by scientists at Washington University School of Medicine in St. Louis and the University of Pittsburgh, suggests that depression, even in children, can increase the risk of heart problems later in life.
“Part of the reason this is so worrisome is that a number of recent studies have shown that when adolescents have these cardiac risk factors, theyre much more likely to develop heart disease as adults and even to have a shorter lifespan,” Robert M. Carney, PhD, the studys first author and a professor of psychiatry at Washington University, said in a news release.
“Active smokers as adolescents are twice as likely to die by the age of 55 as nonsmokers, and we see similar risks with obesity, so finding this link between childhood depression and these risk factors suggests that we need to very closely monitor young people who have been depressed.”
The study was reported March 15 in Miami at the annual meeting of the American Psychosomatic Society.
“We know that depression in adults is associated with heart disease and a higher risk of dying from a heart attack or having serious complications,” Carney said. “What we didnt know is at what stage of life we would begin to see evidence of this association between depression and these cardiac risk factors.”
The researchers studied children who had participated in a 2004 study of the genetics of depression. At the time, their average age was 9. The investigators surveyed 201 children with a history of clinical depression, along with 195 of their siblings who never had been depressed. They also gathered information from 161 unrelated age- and gender-matched children with no history of depression.
In 2011, when the study participants had reached age 16, the researchers surveyed them again, looking at rates of smoking, obesity and physical activity in all three groups of adolescents.
Of children who were depressed at age 9, 22% were obese at age 16. The obesity rate dropped to 17% among the non-depressed siblings and 11% in the unrelated children who never had been depressed, Carney said.
The researchers found similar patterns when they looked at smoking and physical activity. A third of study subjects who were depressed as children had become daily smokers, compared with 13% of non-depressed siblings and 2.5% of the control group, Carney said.
When gauging physical activity, the teens who had been depressed were the most sedentary. Their siblings were a bit more active, and members of the control group were the most active.
When the researchers took a closer look and used statistical methods to eliminate other factors that potentially could have influenced smoking or obesity rates in the depressed children, they found that the effects of depression grew even more pronounced.
In that analysis, Carney said, the siblings of depressed children were five times more likely to smoke than children in the control group, “so depression wasnt the only risk factor for smoking. But the depressed children in the study were another 2.5 times more likely to smoke than their nondepressed siblings.”
Heart disease risk factors were more common in formerly depressed children regardless of whether they remained clinically depressed at the time of the second survey. In fact, only 15% of the depressed cohort still reported depression at the time of the second survey.
The results suggest any history of depression in childhood appears to influence the presence of cardiac risk factors during adolescence, Carney said.
“Depression seems to come first,” he said. “Its playing an important, if not a causal, role. There may be some related genetic influences that give rise to both depression and to heart disease, or at least to these types of cardiac risk behaviors, but more study will be required before we can draw any firm conclusions about that.”