The shorter you are, the more your risk of coronary heart disease, according to a new study. Every 2.5 inches change in height affected your risk of coronary heart disease by 13.5 percent - so a 5 foot 6 inch tall person has a 32% lower risk of coronary heart disease  than a 5 foot tall person because of the latter's shorter stature.

Coronary heart disease is the commonest cause of premature death worldwide. It is the condition where the arteries that supply blood to the heart muscle (coronary arteries) become narrowed due to a deposition of fatty material (plaque) in the walls of the arteries. If a blood clot forms over the plaque then the artery can become completely blocked suddenly giving rise to a heart attack.

Dr Christopher Nelson, British Heart Foundation-funded lecturer who undertook the analysis said: "We had genetic data through the CARDIoGRAM+C4D consortium on almost 200,000 persons with or without coronary heart disease. We examined whether 180 genetic variants that affect height also associated with coronary heart disease. In aggregate, we found that for every change in height of 6.5 cm (approx. 2.5 inches) caused by these variants the risk of coronary heart disease changed on average by 13.5%.

"The more height increasing genetic variants that you carry the lower your risk of coronary heart disease and conversely if you were genetically shorter the higher your risk."

Professor Sir Nilesh Samani, British Heart Foundation Professor of Cardiology at the University of Leicester said, "For more than 60 years it has been known that there is an inverse relationship between height and risk of coronary heart disease. It is not clear whether this relationship is due to confounding factors such as poor socioeconomic environment, or nutrition, during childhood that on the one hand determine achieved height and on the other the risk of coronary heart disease, or whether it represents a primary relationship between shorter height and more coronary heart disease.

"Now, using a genetic approach, researchers at the University of Leicester undertaking the study on behalf of an international consortium of scientists (the CADIoGRAM+C4D consortium) have shown that the association between shorter height and higher risk of coronary heart disease is a primary relationship and is not due to confounding factors."

Nelson added, "We also examined whether the association we found between shorter height and higher risk of coronary heart disease could be explained by an effect of height on known risk factors for coronary heart disease like cholesterol, high blood pressure, diabetes etc. We only observed an association with cholesterol and fat levels which could explain a small proportion (less than a third) of the relationship between shorter height and coronary heart disease. The rest is probably explained by shared biological processes that determine achieved height and the development of coronary heart disease at the same time."

Citation: NEJM.org DOI: 10.1056/NEJMoa1404881