Obesity: Friend or foe for osteoporosis.

Osteoporosis and obesity are worldwide health problems. Interestingly, both are associated with significant morbidity and mortality. Both the diseases have common linkage as bone marrow mesenchymal stromal cells are the common precursors for both osteoblasts and adipocytes. Aging may shift composition of bone marrow by increasing adipocytes, osteoclast activity, and decreasing osteoblast activity, resulting into osteoporosis. Adipocytes secret leptin, adiponectin, adipsin, as well as proinflammatory cytokines, that contributes in pathogenesis of osteoporosis. This new concept supports the hypothesis, that the positive correlation of weight and body mass index (BMI) with bone mineral density (BMD) is not confirmed by large population-based studies. Thus, the previous concept, that obesity is protective for osteoporosis may not stand same as bone marrow fat deposition (adipogenesis) seen in obesity, is detrimental for bone health.