Shorter people may have an increased risk of heart disease, according to a new study that says not just lifestyle but the genes determining our size play a part.
In the past, it was thought that shorter people might be more vulnerable because they had been brought up in poorer socio-economic circumstances or were less well-nourished than many of their peers who grew taller.
A study published in the New England Journal of Medicine, however, breaks new ground by finding the first genetic links between the genes for shorter height and those that increase the risk of coronary heart disease.
According to the researchers led by the cardiologist Professor Sir Nilesh Samani at the University of Leicester, there is an increased relative risk of 13.5% for every 2.5in difference in height.
In other words, someone who is 5ft tall will be 32% more at risk of heart disease than someone who is 5ft 6in.
“Height has a strong genetic determination, and in the last few years a large number of genetic variants have been identified in our DNA that determines one’s height,” said Samani.
“The beauty about DNA is that it cannot be modified by one’s lifestyle or socio-economic conditions.
“Therefore if shorter height is directly connected with increased risk of coronary heart disease, one would expect that these variants would also be associated with coronary heart disease and this is precisely what we found.”
The Leicester team headed an international consortium of researchers, whose work was funded by the British Heart Foundation, the UK’s National Institute for Health Research, the European Union project CVgenes@target, and the Leducq Foundation.
The research looked at genetic data from more than 65,000 people with heart disease and more than 128,000 without.
To try to establish the reasons for the link, the researchers also looked for genes that are associated with known risk factors for heart disease, and found that shorter people were also more likely to have a genetic propensity for higher cholesterol and fat levels – but not for high blood pressure, diabetes or other predisposing factors.
The link with higher cholesterol and fat levels “could explain a small proportion [less than a third] of the relationship between shorter height and coronary heart disease”, said Dr Christopher Nelson, who undertook the analysis of the results.
“The rest is probably explained by shared biological processes that determine achieved height and the development of coronary heart disease at the same time.”
The relationship between shorter height and coronary heart disease was stronger for men than for women.
“In women it was much more attenuated,” Samani told the Guardian. “There are two explanations. One is that it is a gender difference, but it could also be because of the smaller sample size for women, which was only a quarter of the size for the men.”
He hopes the research may lead to new treatments for heart disease, but says there is no reason for shorter people to be screened for heart disease or treated any differently as a result of it.
“The causes of coronary heart disease are quite complex,” he said.
“The findings are relative, so a tall person who smokes will very likely be at much higher risk of heart disease than somebody who is smaller.
“The best advice for avoiding heart disease, according to experts, is to lead a healthy lifestyle, including not smoking, avoiding being overweight, not drinking excessively and exercising regularly.”
