Bone mineral density in adults with the metabolic syndrome: Analysis in a population-based US sample

Background: The metabolic syndrome is associated with low-grade inflammation. It has been suggested that proinflammatory cytokines and low-grade systemic inflammation activate bone resorption and may lead to reduced bone mineral density (BMD), but no previous studies have evaluated the association between the metabolic syndrome and BMD. We examined this relationship in a representative U. S. population-based sample from the Third National Health and Nutrition Examination Survey ( NHANES III, 1988-1994). Methods: We identified adult subjects enrolled in NHANES III with the metabolic syndrome as defined by the criteria of the Adult Treatment Panel III. We conducted a cross-sectional analysis of femoral neck BMD (FN-BMD) for subjects with and without the metabolic syndrome. Analyses were adjusted for relevant covariates and stratified by quintile of body mass index. Results: Among 8197 persons at least 20 yr old who underwent FN-BMD measurement, 1773 (22%) had the metabolic syndrome. After multivariable adjustment, FN-BMD was higher among subjects with the metabolic syndrome (0.86 g/cm(2)) than those without (0.80 g/cm(2); P < 0.0001). When stratified by body mass index, FN-BMD was similar between subjects with and without the metabolic syndrome. Adjusted FN-BMD increased with additional components of the metabolic syndrome ( P < 0.0001 for trend), and there was a significant positive association with abdominal obesity ( P < 0.0001). A subgroup of subjects with diabetes had higher FM-BMD than those without, independent of abdominal obesity. Conclusions: In NHANES III, the metabolic syndrome was not associated with reduced FN-BMD.