Men who have deep belly fat, also called visceral fat, are at higher risk of osteoporosis than men who are in shape, according to a study presented at the annual meeting of the Radiological Society of North America (RSNA).

Miriam Bredella, M.D., a radiologist at Massachusetts General Hospital and associate professor of radiology at Harvard Medical School, commented, “It is important for men to be aware that excess belly fat is not only a risk factor for heart disease and diabetes, it is also a risk factor for bone loss.”

Over 37 million American men over the age of 20 are obese, according to the National Center for Health Statistics, and obesity has been linked to dangerous health issues, such as diabetes, high cholesterol, asthma, cardiovascular diseases, sleep apnea, and joint problems. However, it was previously believed that overweight men have lower chances of suffering from bone loss.

Bredella said, “Most studies on osteoporosis have focused on women. Men were thought to be relatively protected against bone loss, especially obese men.”

The report notes that there are different types of body fat. Subcutaneous fat sits directly beneath the skin, while visceral or intra-abdominal fat is found deep beneath the muscle tissue in the abdominal cavity. The amount of visceral fat stored in a person’s body depends on genetics, diet, and exercise. Extra visceral fat is exceptionally harmful because it has been linked to heart disease.

A study published in August of this year stated that belly fat increases a person’s risk of death even if they are normal weight and a 2009 report said that accumulation of visceral fat is linked to depression.

One particular study, the Osteoporotic Fractures in Men Study, a multi-center observational trial, was conducted in order to find risk factors leading to osteoporosis. The study found that obesity among men was linked to risk of fractures. After this trial, the experts wanted to determine the effect of belly fat on bone strength.

Dr. Bredella and colleagues examined 35 obese males with an average age of 34 and an average BMI (body mass index) of 36.5. The men had CT of their abdomens and thighs to evaluate muscle mass and fat. They also underwent high resolution CT on their forearms, as well as a method called finite element analysis (FEA), which works by analyzing bone strength and forecasting later risk of fracture.

Bredella continued:

“FEA is a technique that is frequently used in mechanical engineering to determine the strength of materials for the design of bridges or airplanes among other things. FEA can determine where a structure will bend or break and the amount of force necessary to make the material break. We can now use FEA to determine the strength or force necessary to make a bone break.”

During the trial, the researchers determined, through the FEA analysis, that men with more visceral and total abdominal fat had lower failure load and stiffness, two tests of bone strength, than men who had less visceral and abdominal fat. No link was discovered between total BMI or age and bone mechanical characteristics.

“We were not surprised by our results that abdominal and visceral fat are detrimental to bone strength in obese men. We were, however, surprised that obese men with a lot of visceral fat had significantly decreased bone strength compared to obese men with low visceral fat but similar BMI,” concluded Dr. Bredella. The findings from the study also revealed that muscle mass was clearly linked to bone strength.

Written by Christine Kearney