The association of waist circumference with bone mineral density and risk of osteoporosis in US adult: National health and nutrition examination survey

Obesity and osteoporosis (OP) are receiving increasing attention. Waist circumference (WC) is an effective indicator for assessing central obesity. Currently, there is controversy regarding the relationship between WC and bone mineral density (BMD), as well as OP. Therefore, our study aims to utilize data from the National Health and Nutrition Examination Survey (NHANES) to evaluate the relationship between WC and BMD, as well as OP, in US adults. This cross-sectional study included subjects aged ≥18 years from the NHANES 1999–2018. Multivariate linear regression models were performed to investigate the association between WC and BMD. Multivariate logistic regression models were employed to assess the relationship between WC and OP. Restricted cubic spline curves were used to assess potential nonlinear association between WC and BMD, OP. Subgroup analysis and sensitivity analysis were performed to assess the robustness of the results. Finally, 11,165 participants (non-OP, n = 10,465; OP, n = 700) were included in the final analysis. The results showed that WC was positively associated with total femur (TF), femoral neck (FN), and lumbar spine (LS) BMD, and might be a protective factor for OP, independent of traditional confounding factors. For each 1 cm increased in WC, TF BMD, FN BMD and LS BMD increased by 0.004 g/cm2, 0.003 g/cm2 and 0.003 g/cm2, respectively, and the risk of OP decreased by 3.1 %. Furthermore, there was a non-linear relationship between WC and BMD, OP. The association remained robust in sensitivity and subgroup analyses. In US adults, there is a positive association between WC and BMD, and WC may be a protective factor for the risk of OP. The association between WC and BMD as well as OP exhibits a non-linear relationship.