Arm circumference is positively correlated with total femur bone mineral density among adults aged 50 years old and above: The NHANES 2013-2020

AbstractBackground:The arm circumference (AC) has been used as an important tool to access the bone mineral density (BMD) of the postmenopausal females. However, the relationship between the AC and total femur BMD remains unclear in American adults. This study aims to explore the relationship between AC and total femur BMD in American adults.Methods:This rigorous study focused on adults aged 50 years old or above, using data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2013 and 2020. The study examined the relationship between AC and total femur BMD in a population-based sample. In order to analyze this relationship, weighted multivariate linear regression and smoothed curve fitting methods were adopted. Additionally, this study used a two-part linear regression model to identify threshold effects. Subgroup analysis and interaction tests were also conducted.Results:Multivariate linear regression analysis revealed a significant positive correlation between AC and total femur BMD in 5536 US adults aged 50-80 years old [β= 0.013, 95% CI: (0.009, 0.016)]. Positive correlations were consistent for all subcategories (including gender, diabetes status, race and physical activity subgroups) except for age and BMI. Furthermore, a non-linear relationship and saturation effect between AC and total femur BMD were identified, with an inverted L shaped curve and an inflection point at 35.4cm.Conclusions:Our study shows that there is a significant positive correlation and saturation effect between AC and total femur BMD in American adults.