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The following is a summary of “Association between A body shape index and bone mineral density in middle-aged and elderly adults: a retrospective analysis of NHANES 2005–2018,” published in the April 2025 issue of Frontiers in Endocrinology by Wang et al. 

Research on central obesity and osteoporosis has grown, but the role of a body shape index (ABSI), which incorporates body mass index (BMI), waist circumference (WC), and height, remained underexplored.  

Researchers conducted a retrospective study to compare ABSI with BMI, WC, and waist-to-height ratio (WHtR) in predicting site-specific changes in bone mineral density (BMD) across anatomical regions.  

They analyzed National Health and Nutrition Examination Survey (NHANES) data from 2005 to 2018, including 12,421 participants, ABSI was calculated using the formula: ABSI = WC/ (BMI² /³ × Height¹ /²). The BMD was measured at 4 sites—total femur (TF), femoral neck (FN), trochanter (TR), and intertrochanter (IN)—using dual-energy X-ray absorptiometry (DXA). Multiple regression models and a generalized additive model (GAM) assessed ABSI’s association with BMD. Regression analyses compared ABSI with BMI, WC, and WHtR to evaluate the predictive value for site-specific BMD.  

The results showed a negative connection between ABSI and BMD in 4 femoral regions (P< 0.01) after full covariate adjustment. Smoothed curve fitting indicated a nonlinear relationship and threshold effect between ABSI and BMD in middle-aged and older individuals, with an inverted J-shaped curve observed across all femoral regions.The ABSI demonstrated significant negative associations with BMD at all femoral sites (β = -0.27 to -0.31, P-trend< 0.000001), while BMI, WC, and WHtR showed positive correlations, with WHtR exhibiting the strongest effect (β = 0.41–0.69). These findings highlight ABSI’s potential to identify central adiposity-related bone loss overlooked by conventional obesity metrics.  

Investigators concluded that ABSI’s strong inverse relationship with femoral BMD, consistent across nonlinear analyses, established it as a new biomarker for central adiposity-related skeletal fragility, uniquely reflecting visceral fat-driven metabolic disorder relevant for osteoporosis risk assessment in both normal-weight and obese individuals, unlike conventional indices primarily indicating mechanical loading benefits. 

Source:frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2025.1506841/full