Excess visceral fat may increase osteoporosis risk in women
MedWire News: Women with increased visceral fat around the abdomen have decreased bone mineral density (BMD), which may be partly mediated by increased bone marrow fat, US research shows.
"Despite being a risk factor for cardiovascular and metabolic disease, obesity has been thought to protect against osteoporosis," said Miriam Bredella (Harvard Medical School, Boston, Massachusetts) at the Radiological Society of North America Annual Meeting, held in Chicago, Illinois, this week.
However, "not all body fat is the same," she remarked, adding that visceral adiposity and bone marrow fat may have damaging effects on bone health.
To investigate the association between BMD and abdominal subcutaneous, visceral, and total fat, as well as bone marrow fat, Bredella and team studied 50 premenopausal women with a mean body mass index (BMI) of 30 kg/m2.
Each woman underwent magnetic resonance spectroscopy to evaluate the bone marrow fat at the L4 vertebra, and quantitative computed tomography to assess abdominal subcutaneous, visceral, and total fat deposits, and trabecular BMD.
Bredella reported a significant inverse association between visceral fat and BMD and between vertebral bone marrow fat and BMD.
Furthermore, vertebral bone marrow fat correlated significantly with visceral fat, independently of BMD, while multivariate regression analysis confirmed that vertebral bone marrow fat was a significant predictor of trabecular BMD, independent of age, BMD, and visceral adiposity.
In contrast, subcutaneous and total abdominal fat did not correlate with either BMD or bone marrow fat.
"We know that obesity is a major public health problem," said Bredella. "Now we know that abdominal obesity needs to be included as a risk factor for osteoporosis and bone loss."
While bone loss is more common in women, the research team is currently conducting a study to determine whether abdominal fat is also a risk factor for bone loss in men.
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By Laura Dean