Is being shorter really a risk factor for developing heart disease?
There are several studies which have found that people with shorter stature have a greater risk of developing heart disease than taller people. In this study they found that every 2.5 inch change in height affects coronary heart disease risk by 13.5%. The big question is why is there a difference? Is it based on lifestyle choices, just the act of people tall, or for some other reason? What makes this study special is that they did genetic analysis to determine if people’s genes could account for these differences. Genes are the instructions on how to make you, and all the things your body makes are dictated by those instructions. Many people have normal copies of genes for height and that makes them normal height, unless they underwent starvation or nutrient deficiency. However some people have differences in these genes from normal people and these genetic differences are called single nucleotide polymorphisms or SNPs. Some SNPs can make some people taller than average and other SNPS can make people shorter than average. Many of these SNPs are passed down to future generations.
When they ran the genetic profiles of taller and shorter people what did they find?
Some of the genetic differences that can determine height and heart disease risk are for bone morphogenetic protein (BMP), transforming growth factor β (TGF-β), and Insulin related growth factor-1 (IGF-1) pathways. SNPs in these genes that make people grow taller and reduce their risk of heart disease, possible just by making the heart larger. Your heart is about the size of your fist so taller people have larger hearts and along with it, have larger coronary arteries. This means a 50% blockage of a small coronary artery has less total blood flow than a 50% blockage of a larger one. There isn’t much you can do about this but interestingly, people who are shorter are more likely to have SNPs in genes for LDL cholesterol (what we know of as bad cholesterol) and triglycerides (which is also called blood fats) and as a result have higher blood cholesterol and triglyceride concentrations. Up to a third of the difference in heart disease risk between taller and shorter people were explained just by cholesterol and triglycerides. The good news is that this is a modifiable risk because we have effective medical therapy for both high cholesterol and triglycerides.
Dr. Michael White, Dept. of Pharmacy Practice, UConn School of Pharmacy