Genetics Link Height to Heart Disease
The New England Journal of Medicine recently published research linking height and coronary artery disease through the study of genetics. Doctors have known since the 1950s about the link between short stature and coronary artery disease, “but the reason behind this really hasn’t been completely clear,” said Nilesh Samani, a cardiologist at the University of Leicester in the U.K.
Samani and his colleagues looked at the genes of nearly 200,000 people, “and we found a very striking relationship,” Samani said. “We’ve been rather simplistic in our view of what causes coronary artery disease. We thought about traditional risk factors and then genes that might cause coronary disease. But what the study highlights is that developmental processes are going on that probably have an influence on height, and they probably also have an influence on blood vessels of the heart in a way that predisposes you to getting coronary artery disease.”
The challenge now is to ferret out the actual genetic variations that underlie both height and heart disease. “Eventually, of course, there may be some treatments that could emerge from this, but I wouldn’t want to say that’s a short-term possibility,” Samani said.
For someone 2.5 inches shorter than average, the risk of coronary artery disease increases by about 13.5 percent. And the shorter you are, the larger the effect; however, the risk is much smaller than the risk posed by smoking or high cholesterol. Most of the height genes had no obvious connection to heart disease, though a few of them did, such as a trait related to LDL cholesterol and another that influences triglycerides. Those account for less than a third of the effect, leaving the root cause of this link mainly a mystery.
The study also found that people who had more of the height-increasing genetic markers were at lower risk for coronary artery disease. People who had the most height-increasing genetic markers were 26 percent less likely to have coronary artery disease than those with the fewest height-increasing genetic markers.
Shared biologic processes that determine achieved height and the development of atherosclerosis may explain some of the association, notes the study. “We observed significant associations only with levels of low-density lipoprotein cholesterol and triglycerides, accounting for approximately thirty percent of the association,” researches said.
David Goldstein, Director of the Institute for Genomic Medicine at Columbia University is enthusiastic about the opportunities the study brings to the medical community. “As we begin to systematically characterize the genetic bases of these traits, it’s going to open up a whole bunch of brand new windows into biology,” Goldstein says. “And that’s really what I find exciting.”
The study of height and heart disease is also a reminder that traits are usually the result of many different genes acting in concert, so it’s not so simple to alter these traits, for example, to treat or prevent disease.
One major problem with the study is that it looked mostly at white males. With an increase in the diversity of subjects, perhaps scientists could have a better understanding of these genetic traits and markers.