People who are genetically predisposed to storing belly fat, or having an apple-shaped body type, could face a higher risk of type 2 diabetes and heart disease, researchers said on Tuesday.
The research has found that for those people who are genetically at a greater risk of having a higher waist-to-hip ratio adjusted for body mass index are likely to have an increased risk of developing these conditions.
“People vary in their distribution of body fat — some put fat in their belly, which we call abdominal adiposity and some in their hips and thighs,” says Sekar Kathiresan, Associate Professor at Harvard Medical School in Boston.
“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’,” Kathiresan added.
The study in the Journal of the American Medical Association (JAMA) suggests a person’s genetic makeup may cause health problems down the road.
However, researchers have noted that although the findings obtained from the previous observational studies have indicated that abdominal fat is associated with type 2 diabetes and coronary heart disease, experts have said that it remains unclear whether these associations represent a causal relationship.
Dr. Sekar Kathiresan, of Massachusetts General Hospital in Boston, and colleagues conducted a study to investigate whether being genetically inclined to have an increased waist-to-hip ratio (WHR) adjusted for BMI (a measure of abdominal fat) was linked to cardio metabolic traits (such as lipids, glucose, insulin, and systolic blood pressure), and type 2 diabetes and coronary heart disease.
The team gathered data from 4 genome-wide association studies conducted between 2007 and 2015, which included up to 322,154 participants, and individual-level, cross-sectional data from the UK Biobank collected between 2007 and 2011, which included data from a further 111,986 people. Estimates for cardiometabolic traits were based on this combined data set.
Analyze did show that being genetically predisposed to a higher WHR adjusted for BMI was connected with increased levels of quantitative risk factors, including lipids, glucose, insulin, and systolic blood pressure, and a greater risk of developing type 2 diabetes and coronary heart disease.
Previous research had identified 48 gene variants associated with waist-to-hip ratio, resulting in a genetic risk score. The findings agree with previous studies.
“For example, increased abdominal adiposity at a given BMI has been proposed as an explanation for the excess risk of coronary heart disease observed in South Asians,” the authors explain. “Similarly, greater abdominal adipose tissue at a given BMI has been proposed to underlie the excess risk of coronary heart disease at a given BMI among men compared with women,” they add.
“Although a substantial focus of drug development has been toward therapeutics to reduce overall adiposity, there has been little effort toward the development of therapies that modify body fat distribution to reduce abdominal adiposity,” say the authors. Kathiresan and team conclude:
“These results provide evidence supportive of a causal association between abdominal adiposity and the development of type 2 diabetes and coronary heart disease.”
Limitations of the study include the fact that there is a small chance that the findings from the study represent a “shared genetic basis” between WHR adjusted for BMI and coronary heart disease, instead of a causal relationship.