Obesity, bone mineral density link found

TORONTO, Nov. 26 (UPI) -- A protein may explain the relationship between obesity and both bone mineral density and reduced susceptibility to fractures, Canadian researchers said.

Researchers at the University of Toronto said circulating adiponectin -- a protein -- levels are significantly lower in obese humans and rodent models than in lean controls.

Dr. Michael C. Archer, Dr. Wendy E. Ward, Dr. Kafi Ealey and Jovana Kaludjerovic said that it is known that excess body weight and elevated body mass index are strongly correlated with high bone mineral density, and that weight loss is associated with loss of bone mineral density and increased risk of fractures. However, the mechanism was unclear.

This study, published in the December issue of Experimental Biology and Medicine, found elevated circulating adiponectin was associated with lower bone mass and weaker bones in growing mice compared to control animals. Furthermore, these effects of adiponectin were observed in the absence of differences in body weight between the two groups of mice.

"A unique and important feature of these mice is that they exhibit significantly elevated circulating adiponectin but have similar body weights as control animals, thus eliminating obesity from confounding the study findings – mechanical load resulting from an obese state can modulate bone metabolism," Archer said in a statement.