Is obesity in women protective against osteoporosis?

Abstract

The belief that obesity is protective against osteoporosis has recently come into question. The latest epidemiologic and clinical studies have shown that a high level of fat mass might be a risk factor for osteoporosis and fragility fractures. Further, increasing evidence seems to indicate that different components of the metabolic syndrome, ie, hypertension, increased triglycerides, reduced high-density lipoprotein cholesterol, are also potential risk factors for the development of low bone mineral density and osteoporosis. This review considers both the older and more recent data in the literature in order to evaluate further the relationship between fat tissue and bone tissue.

Keywords: adipocytes; body mass index; bone mineral density; fat mass; fractures.

Figure 1

Several cell lines deriving from a common mesenchymal stem cell. The presence of different stimuli may induce differentiation of the progenitor into one cell line instead of another. However, this event might underscore the presence of a certain degree of plasticity among the cell lineages.

Figure 2

A complex link between adipocytes and bone cell exists. Several cytokines are secreted by fat tissue and act on bone cells. In particular, several proinflammatory cytokines (eg, IL-6 and TNF-α) act as osteoclastogenic factors with a potentially stimulating mechanism. Abbreviations: IL-6, interleukin-6; TNF-α, tumor necrosis factor alpha.