More Abdominal Fat Linked to Unhealthy Bones in Women
A recent clinical investigation shows that premenopausal women who are otherwise healthy but have larger waistlines have lower bone quality and less bone formation than those who had less abdominal fat. Although previous studies have shown that obesity may protect against osteoporosis (a condition characterized by weak bones), recent studies have challenged this belief. Other scientists have found that central obesity is inversely associated with bone mineral density (BMD).
Adi Cohen, MD, of Columbia University in New York City, and colleagues believe that since obesity is a growing public health problem, it is necessary to study the effects of truncal fat to bone quality and future risk for fractures. Their study involved 40 Caucasian women, ages 18 to 48, who had normal menses, normal BMD, and no history of fractures in adulthood. They had a mean body mass index (BMI) of 25.8 kg/m2 and their total body fat averaged 35.5%, while trunk fat averaged 32.5%.
They were grouped into three, depending on amount of trunk fat, and they found that those who had the least had normal BMI, while those with the most also had the largest BMI (obese). After performing bone biopsies and imaging studies, they also found that women who had the largest trunk fat had significantly lower trabecular bone volume, number, thickness, and stiffness compared to those who had the least trunk fat. These showed that truncal obesity was inversely related with rate of bone formation and bone volume.
Although mechanical loading due to increased body fat has been believed to positively contribute to bone mass, the paradoxical effects of obesity on bone density may be due to the release of cytokines (inflammatory substances) from abdominal fat. Others believe that obesity may cause an increase in bone marrow fat and a decrease in bone-formation markers.
Bankhead, C. Belly Fat Weighs on Women’s Bones. MedPage Today.