Kids that have an absent parent may be more likely than other children to start drinking and smoking before they reach their teens, a U.K. study suggests.
The good news for parents is that few kids drink or smoke by age 11, the study found.
But kids who experienced the death or absence of a biological parent by age 7 were more than twice as likely to smoke and almost 50 percent as likely to drink by age 11 as their peers still living with both parents.
"We know from previous studies that people who experienced parental absence in childhood are more likely to smoke and/or drink in adulthood," said lead study author Dr. Rebecca Lacey of the University College London.
"These findings suggest that the uptake of risky health behaviors may be occurring earlier in life than we previously thought," Lacey added by email.
For the current study, researchers examined data on 10,940 children born in the U.K. from September 2000 to January 2002.
Children and their families were surveyed when children were 9 months old, and again at 3, 5, 7 and 11 years. During the last survey, researchers asked kids directly if they had ever smoked a cigarette, had an alcoholic drink or consumed enough to feel drunk.
Overall, 29 percent of boys and 28 percent of girls had a parental absence by age 7, researchers report in the Archives of Disease in Childhood.
Slightly more than half of the kids who experienced this absence had the parent die or leave by the time they were 3 years old. Nearly all of the absent parents were fathers.
By the time kids were 11 years old, 15 percent of boys and 11 percent of girls said they had tried alcohol, while 12 percent of boys and 7 percent of girls reported feeling drunk at least once.
Kids with an absent parent were more than twice as likely to report drinking to excess than other children.
Very few kids had a parent die early in their childhood. Compared to children who had a parent absent for other reasons, however, kids who experienced the death of a parent and who reported drinking were more than 12 times as likely to report having consumed enough to feel drunk.
One limitation of the study is that researchers didn't look at parental deaths or departures after age 7, making it impossible to see how an absence that started between ages 7 and 11 might influence risk behaviors, the authors note.
Even so, the findings add to a growing body of evidence suggesting that family structures and dynamics can influence whether kids develop substance abuse issues, said Suzannah Creech, a psychology researcher at Brown University in Providence, Rhode Island, and the Veterans Health Administration in Waco, Texas.
When a parental absence does happen, there are still things the remaining parents and caregivers can do to help minimize the odds that children will drink or smoke, Creech, who wasn't involved in the study, said by email.
"Children can be profoundly resilient to life stressors when they also have a positive and consistent attachment figure such as a parent, grandparent or older sibling," Creech said. "Making sure children's basic needs are met and that they have a positive relationship with an attachment figure can be protective factors."