The research, presented today at the annual scientific session of the American College of Cardiology in Atlanta, reveals that women as young as 19 who are obese can develop left ventricular hypertrophy (LVH), a thickening of a wall of the heart that can also increase the risk of an enlarged heart. Both are predictors for cardiovascular disease later in life.
"We found that LVH and an enlarged heart can begin as early as the teen years, and that weight appears to play a major role in this change in the geometry of the heart," says the study's lead author, Dr. Tom Kimball, director of echocardiography at Cincinnati Children's Hospital Medical Center.While young black women in the study were found more likely to have an enlarged heart than young white women were, Kimball says this has nothing to do with ethnicity or blood pressure. The black women, he says, were simply more overweight.
LVH is a thickening of the left wall inside the heart, the main station where blood is pumped. This can sometimes cause the heart muscle to enlarge as well, which can hurt the heart's ability to pump blood and ultimately lead to serious damage.
"Our study was one of the first to show that these conditions can develop as early as the teen years, and that weight appears to play a role," Kimball says.
Dr. Dan Fisher, a cardiologist at New York University Medical Center, says the study has merit, but more research is needed before recommendations can result.
"It's a good study to show correlation between obesity in young women and heart disease, but now we need to understand whether targeting these people with testing that identifies LVH will actually impact their future cardiovascular risks," Fisher says.
Until researchers determine whether losing weight can reverse the process -- which he suspects it may -- the message right now is the importance of controlling weight as early as the teen years.
The new study looked at 575 healthy young women, including 302 blacks and 273 whites, whose average age was 19. Each was given a screening known as echocardiogram. This combines a traditional electrocardiogram, which measures functions of the heart, with an ultrasound exam that helps visualize what the heart looks when it is functioning. In this instance, the test measured the size of the heart and the thickness of its left wall.
Based on the findings, the women were placed into one of four categories: normal (heart size and wall thickness were normal); concentric remodeling (the wall was thick, but heart size was normal); eccentric hypertrophy ( the heart was enlarged, but wall thickness was normal); and concentric hypertrophy (the heart was enlarged, and the wall was thick).
Doctors then recorded the women's blood pressure and their body mass index (BMI), which calculates body fat. They correlated these to the echocardiograms.
Some 75 percent of the women were normal; 5 percent had a thickened heart wall with normal heart size; 13 percent had an enlarged heart with normal wall thickness; and 7 percent were found to have both an enlarged heart and thickening of the heart wall.
While the number of black women with a thickened heart wall was greater than the number of white women with this problem, race not considered a significant factor once blood pressure and BMI were factored into the equation.
"We found obesity was the link to the heart abnormalities," Kimball says. In the study, 33 percent of the black women were obese, compared to 16 percent of white women.
Ultimately, researchers say their study offers important evidence that obesity in the teen years can increase the risk of cardiovascular disease later in life. Further, they say, echocardiograms should be considered for all obese young women to determine if LVH has occurred.
"Until we know for certain if having this information will impact the future of cardiovascular disease in this group, we should not rush into routine screening," he says.
Although both experts agree on the importance of weight control in relation to cardiovascular risks, they also stress young women should not take weight loss to the extreme.
Being severely underweight can cause immediate and sometimes irreversible damage to the heart, as well as future fertility problems and other health risks, they explain.
"The goal is maintain normal weight, not underweight," Fisher says.
What To Do
To learn more about left ventricular hypertrophy (LVH), check out the The Mayo Clinic.
To learn how an echocardiogram is performed, visit The Heart Site.