.
‘A pattern of gene variants associated with abdominal adiposity increases the risk for type 2 diabetes and coronary heart disease, as well as the incidence of several cardiovascular risk factors.’
Sekar Kathiresan, director of the
MGH Center for Genomic Medicine, associate professor of Medicine at Harvard Medical School, and senior author of the
JAMA
report, said, "We tested whether genetic predisposition to abdominal
adiposity was associated with the risk for type 2 diabetes and coronary
heart disease and found that the answer was a firm 'yes'."
While several observational studies have reported greater incidence
of type 2 diabetes and heart disease among individuals with abdominal
adiposity, they could not rule out the possibility that lifestyle
factors - such as diet, smoking and a lack of exercise - were the actual
causes of increased disease risk. It also could have been possible that
individuals in the early stages of heart disease might develop
abdominal adiposity because of a limited ability to exercise. The
current study was designed to determine whether body type really could
increase cardiometabolic risk.
To answer that question, the research team applied a genetic
approach called mendelian randomization, which measures whether
inherited gene variants actually cause outcomes such as the development
of a disease. Using data from a previous study that identified 48 gene
variants associated with waist-to-hip ratio adjusted for body mass index
- an established measure for abdominal adiposity - they developed a
genetic risk score. They then applied that score to data from six major
genome-wide association studies and to individual data from the U.K.
Biobank - a total research group of more than 400,000 individuals - to
determine any association between a genetic predisposition to abdominal
adiposity and cardiometabolic disease and its risk factors.
The results clearly indicated that genetic predisposition to
abdominal adiposity is associated with significant increases in the
incidence of type 2 diabetes and coronary heart disease, along with
increases in blood lipids, blood glucose and systolic blood pressure. No
association was found between the genetic risk score and lifestyle
factors, and testing confirmed that only the abdominal adiposity effects
of the identified gene variants were associated with cardiometabolic
risk.
"These results illustrate the power of using genetics as a method of
determining the effects of a characteristic like abdominal adiposity on
cardiometabolic outcomes," says lead author Connor Emdin, of the
MGH Center for Genomic Medicine and the Cardiology Division. "The lack
of association between the body type genetic risk score and confounding
factors such as diet and smoking provides strong evidence that abdominal
adiposity itself contributes to causing type 2 diabetes and heart
disease."
Emdin continues, "Not only do these results allow us to use body
shape as a marker for increased cardiometabolic risk, they also suggest
that developing drugs that modify fat distribution may help prevent
these diseases. Future research also could identify individual genes
that could be targeted to improve body fat distribution to reduce these
risks."
Source: Eurekalert