Heart Disease More Common In Shorter People, Due Partly To Cholesterol And Fat Levels

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Smoking and poor diet still drive heart disease more than any other factors, however. Photo courtesy of Shutterstock

Up where the air is rarified, taller people apparently are living healthier. Relying on a novel method of genetic testing, a new study published in the New England Journal of Medicine upholds prior theories that suggest taller people face lower risks for certain kinds of heart disease than shorter people.

In 1994, scientists found no link between a person’s height and lifetime risk for heart disease. But in the two decades that followed, multiple studies have validated the theory that shorter people are at a disadvantage. In 2010, research found cardiovascular disease morbidity and mortality were 50 percent more common in shorter people. In 2012, the list of disadvantages increased to include greater risks for coronary disease, certain types of stroke, heart failure, stomach and oral cancers, chronic obstructive pulmonary disease, mental disorders, liver disease, and, looking at the big picture, death from any cause.

In contrast to prior work that looked mainly at the physical evidence, otherwise known as the epidemiology, the latest study used genetic samples. The main benefit of this, the researchers wrote in their report, “is that genotypes (because they are randomly distributed at birth) are unlikely to be confounded by lifestyle or environmental factors.” Even if people don’t smoke or grow up with the stresses of poverty, both of which would raise their risk for heart disease, they may still carry an underlying genetic risk. Testing only this base risk enables scientists to see the connection between height and disease most clearly.

The study comprised nearly 200,000 people. Roughly 65 percent of them had a history with heart attacks, and 74 percent of the heart disease cases were men. Ultimately, the research team found that for every 2.5 inches taller someone was, he or she faced a 13.5 percent reduction in risk. However, the advice for people of all heights pretty much stays the same, says Dr. Nilesh Samani, professor of cardiovascular sciences at the University of Leicester.

"I wouldn't say shorter people need to take greater precautions,” Samani, the study’s senior author, told the BBC, “because if you're 6-foot-1 you still need to stop smoking.”

Though not all mechanisms are clear to Samani and his colleagues, some of the underlying causes seemed to rest with LDL cholesterol levels (so-called “bad cholesterol”) and triglycerides, a type of fat found in the blood. With each 2.5-inch decrease in height, LDL levels increased by 45 percent and triglycerides by 32 percent.

The study comes with some limits, the authors concede. Even though the genetic component can control for confounding factors like smoking and poor diet, it can’t control for lifestyle factors that are a direct consequence of being shorter. It may be the case, for instance, that genetically determined shortness, for whatever reasons, influences people to take up behaviors that increase their heart disease risk. In this case, genes would only partly determine someone’s risk, and the lifestyle factors could still cloud the data.

However, now that they know some of the pathways involved with heart disease risk, Samani argues, they may be able to develop novel treatments that target them directly. Smoking and obesity are still the main drivers of the some 610,000 annual deaths in the U.S. resulting from heart disease. It remains the leading cause of death in both men and women.

Source: Nelson C, Hamby S, Saleheen D, et al. Genetically Determined Height and Coronary Artery Disease. New England Journal of Medicine. 2015.

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