(HealthDay)—Children whose parents use "harsh" physical punishment such as slapping or shoving may end up in relatively poorer physical health as adults, a new study suggests.
Researchers found that of more than 34,000 U.S. adults in a government health study, those who said they were harshly disciplined as kids had slightly higher risks of obesity, arthritis and heart disease.
Harsh punishment was defined as being hit, slapped, pushed or grabbed at least sometimes.
The findings, published online July 15 and in the August print issue of Pediatrics, do not prove that physical punishment, itself, affects kids' long-term health.
"It's an association. We can't say the punishment is causing the physical health problems," said lead researcher Tracie Afifi, of the University of Manitoba in Winnipeg, Canada.
But, she added, the findings add to evidence that physical punishment can harm kids. A number of studies have linked such punishment—even spanking—with problems such as aggressive behavior and poorer emotional well-being.
"Kids need discipline," Afifi said. "But it shouldn't involve physical force."
The findings are based on 34,226 U.S. adults who took part in a government health study in 2004 and 2005. Just under 4 percent fit the definition of being harshly punished as kids.
Overall, their rate of obesity was higher, compared to adults who reported no harsh physical punishment: about 31 percent, versus 26 percent. They also had higher rates of arthritis (22.5 percent, versus 20 percent) and heart disease (9 percent, versus 7 percent).
Afifi's team was able to account for some other factors—including family income and whether kids suffered more severe abuse, physical or otherwise. "Harsh" discipline was still linked to a 20 percent to 28 percent increased risk of the three adulthood health problems.
A child-abuse expert not involved in the study agreed that physical punishment is potentially harmful. Plus, while it may get a child to stop the bad behavior right now, it does not work in the long run, said Dr. Rachel Berger, of the Children's Hospital of Pittsburgh.
"There's a tremendous and growing literature showing that corporal punishment is not necessary, and that there can be detrimental effects," Berger said.
The current study, though, has some limitations, said Berger, who co-wrote an accompanying editorial.
One issue, according to Berger, is how "harsh" physical punishment was defined. It was based on one question: "How often did a parent or other adults living in your home push, grab, shove, slap or hit you?" (The study did not ask specifically about "spanking"—the most common form of childhood physical punishment.)
Only about 4 percent of adults said they'd at least sometimes been subjected to those forms of discipline. On the other hand, 38 percent reported more-severe child maltreatment—including physical abuse that left kids bruised or injured.
Berger said fewer adults would be expected to report severe maltreatment, versus harsh punishment. So that raises doubts about how the question was asked, and how respondents were interpreting it, according to Berger.
And since the study did not look at milder physical punishment, the findings cannot be used to condemn everything down to the occasional whack on the behind. "You can't say, based on this alone, 'OK, now we know we shouldn't use any physical punishment,'" Berger said.
Another researcher not involved in the work said he did not find the results all that compelling. The study looked at seven adulthood health conditions, and found that harsh physical punishment was statistically linked to three of them.
And even then, the links were not strong in statistical terms, noted Christopher Ferguson, an associate professor of psychology at Texas A&M International University, in Laredo.
Ferguson said he is no advocate of spanking, but added, "I wouldn't want parents who have spanked their kids to become alarmed by this."
Study author Afifi agreed that parents should not feel alarmed—or guilty. "We're not trying to point the finger at parents," she said. But based on the body of research, parents should try to learn nonphysical types of discipline, she added.
And if you're not sure how to do that? "I would recommend that parents start by talking to their pediatrician," Afifi suggested.
Based on past surveys, the vast majority of Americans were spanked as kids. So it may be pretty ingrained in the culture, noted Berger at Children's Hospital of Pittsburgh.
"But just because you were spanked," she said, "doesn't mean it's right for your child."
Explore further: Study shows spanking boosts odds of mental illness
The American Academy of Pediatrics has tips on disciplining children.