By Rob Stein
Washington Post Staff Writer
Thursday, December 6, 2007
Being overweight as a child significantly increases the risk for heart disease in adulthood as early as age 25, according to a large new study that provides the most powerful evidence yet that the obesity epidemic is spawning a generation prone to serious health problems later in life.
The study, of more than 276,000 Danish children, found that those who were overweight when they were 7 to 13 years old were much more likely to develop heart disease between the ages of 25 and 71 -- even those who were just a little chubby as kids, and possibly regardless of whether they lost the weight when they grew up.
"This is incredibly important," said Jennifer L. Baker of the Institute of Preventive Medicine in Copenhagen, who led the research, being published today in the New England Journal of Medicine. "This is the first study to convincingly show that excess childhood weight is associated with heart disease in adulthood, or with any significant health problem in adulthood."
The study was published with an analysis of U.S. health statistics that projects teenage obesity will raise the nation's rate of heart disease by at least 16 percent by the year 2035, causing more than 100,000 additional cases.
"This offers a frightening glimpse of what we have in store," said David S. Ludwig of Harvard Medical School, who wrote an editorial accompanying the studies. "The epidemic of childhood obesity is not a cosmetic problem. It can have profound long-term consequences for adult illness and death."
The proportion of U.S. children who are overweight has tripled since 1976 and now totals more than 9 million. The sharp rise has already caused a jump in children developing Type 2 diabetes, which used to be known as adult-onset diabetes because it occurred almost exclusively among adults. Children are also increasingly being diagnosed with high blood pressure and cholesterol, which raised fears they will be more likely to develop heart disease -- the nation's leading cause of death.
Previous studies had produced mixed results. "Although studies have hinted there may be an association, none has been able to confirm it," Baker said. "They didn't have the power to show the association."
Baker and her colleagues analyzed information collected about the height and weight of 276,835 Danish schoolchildren between 1955 and 1960 and scoured hospital records from between 1977 and 2001 to see which of them went on to be hospitalized for heart problems as adults.
The risk increased with any amount of excess weight in childhood, the researchers found.
"Even a few extra pounds increases the risk," Baker said. "That's the very frightening message from our results."
For example, a 4-foot-1-inch boy who weighed about 61 pounds at age 7 faced a 12 percent increased risk of developing heart disease between the ages of 25 and 71, compared with a similar boy who was at the normal weight of about 52 pounds.
The greatest increased risk, however, was for the heaviest older children, the researchers found.
For example, a 5-foot-1-inch boy who weighed 121 pounds at age 13 had a 34 percent greater risk compared with a boy of the same height and age who had a normal weight of 96 1/2 pounds. The risk was 51 percent higher if the boy weighed 132 1/2 pounds.
The risk was significantly lower for those who were overweight at age 7 but not at age 13, indicating that a child who can lose excess weight while still young, and remain at a normal weight, can reduce the extra risk substantially.
"This gives us hope," Baker said. "This really suggests that if an intervention occurs during this short period of time to help a child attain and maintain a normal weight, the risk of heart disease could be reduced."
Because the researchers did not have data on the subjects' adult weight, they could not definitively determine whether the increased risk was due to the effects of being overweight when young or because overweight children are more likely to become overweight adults.
"We speculate that it's the early exposure," Baker said. "It's plausible that because these heavy children have these risk factors and are exposed to them early in life and continue to be exposed to them, that leads an increased risk in heart disease."
In the second study, Kirsten Bibbins-Domingo of the University of California at San Francisco and colleagues used federal statistics from the year 2000 and other data to project that by the time today's adolescents turn 35 in 2020, up to 37 percent of men and 44 percent of women will be obese, resulting in an additional 100,000 cases of heart disease by 2035. Bibbins-Domingo said the projections would have been even higher if the analysis had included the Danish data.
"We took a very conservative approach," she said.
Melinda Sothern, an expert on childhood obesity at Louisiana State University in New Orleans, said the findings are disturbing because they suggest not only that overweight children experience more disease and disability in childhood but also that many are also destined to be more sickly young adults.
"Overweight children are already losing their childhood. They can't do the same types of activities as healthy-weight children," she said. "Now they will lose their early adulthood as well."
Ludwig likened the childhood obesity epidemic to the threat from global warming, saying that even though hard evidence is just now emerging about the consequences of the threat, society should act more aggressively to counter the trend.
"We don't have all the data yet. But by the time all the data comes in it's going to be too late," Ludwig said. "You don't want to see the water rising on the Potomac before deciding that global warming is a problem. We need national policies to address childhood obesity, too."