Men with Belly Fat Need to Look Out for Bone Loss
While women are usually the focus of osteoporosis prevention, a new study says overweight men are at a higher risk than previously thought.
--by Suzanne Boothby
Men now have one more reason to lose belly fat: bone loss and decreased bone strength. Visceral, or deep belly, obesity is a risk factor for men developing osteoporosis, according to a study presented this week at the annual meeting of the Radiological Society of North America.
Genetics, diet, and exercise level all affect how much visceral fat gets stored in the body. This excess fat is considered particularly dangerous because previous studies have linked it to an increased risk of heart disease.
Obesity in general is associated with many common health problems, including cardiovascular disease, diabetes, and high cholesterol. More than 37 million American men ages 20 and older are obese, according to the National Center for Health Statistics.
The Expert Take
The connection between increased body weight and bone loss for men has gone largely unnoticed until recently.
"Most studies on osteoporosis have focused on women,” said study author Miriam Bredella, M.D., a radiologist at Massachusetts General Hospital and associate professor of radiology at Harvard Medical School. “Men were thought to be relatively protected against bone loss, especially obese men.”
But the connection between belly fat and bone loss is not surprising to many doctors. People who gain belly fat are at a greater risk of serious health problems, including death, than people who accumulate fat in other areas—and men are more likely than women to gain weight around the waist, according to Michael Jensen, M.D., an endocrinology specialist at the Mayo Clinic.
“We were not surprised by our results that abdominal and visceral fat are detrimental to bone strength in obese men," Bredella said. "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.”
Source and Method
Bredella and her research team evaluated 35 obese men with a mean age of 34 and a mean body mass index (BMI) of 36.5. The men underwent a computed tomography (CT) scan of the abdomen and thigh to assess fat and muscle mass, as well as a very high resolution CT scan of the forearm and a technique called finite element analysis (FEA), in order to assess bone strength and predict fracture risk.
FEA is a technique frequently used in mechanical engineering to determine the strength of materials for the design of bridges or airplanes. The method can also be used to determining the strength or force necessary to make a bone break, Bredella said.
In the study, FEA analysis showed that men with higher visceral and total abdominal fat levels had lower failure load and stiffness, two measures of bone strength, compared to those with less visceral and abdominal fat. Researchers found no association between age or total BMI and the mechanical properties of subjects' bones.
Increased belly fat has an impact on bone health and strength in men, and can lead to osteoporosis.
"It's 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," Bredella said.
The study also found that muscle mass was positively associated with bone strength, so men who engage in more exercise to help lose belly fat could see results in this arena as well.
The Osteoporotic Fractures in Men Study, a multi-center observational study designed to determine risk factors for osteoporosis, inspired the current study of belly fat. In it, scientists found that male obesity in general was associated with greater bone fracture risk.
The Brazilian Osteoporosis Study published in 2009 examined bone health-related nutrients and their impact on the incidence of osteoporotic fractures in men and women. They study found that while calcium is important, other nutrients, including protein, phosphorus, magnesium, and vitamins D and K, are also key contributors to bone health.