Qiwang He ^1,2 Bo Chen ³ Fuchao Liang ⁴ Zhiwen Zhang ^2*

• ¹ College of Acupuncture and Orthopedics, Hubei University of Chinese Medicine, Wuhan, Hubei Province, China
• ² Department of Orthopedics, Affiliated Hospital of Hubei University of Chinese Medicine, Wuhan, Hebei Province, China
• ³ Department of Endocrinology Center for Clinical Evidence-Based and Translational Medicine, Xiangyang Central Hospital, Xiangyang, China
• ⁴ Department of Urology, Xiangyang Central Hospital, Xiangyang, China

Background: Studies on the relationship between the atherogenic index of plasma (AIP) and bone mineral density (BMD) among adult women in the United States are limited. The purpose of this study was to explore this association using a sizable, nationally representative sample.Methods: Data from the 2011 to 2018 National Health and Nutrition Examination Survey (NHANES) were used in this observational study. The AIP was computed as log10 (triglycerides/high-density lipoprotein cholesterol). Total BMD was measured via dual-energy X-ray densitometry. We constructed multiple linear regression models to evaluate the correlation between the AIP and BMD. The non-linear relationship was characterized by smooth curve fitting and generalized additive models. We also conducted subgroup and interaction analyses.In this study, we included 2,362 adult women with a mean age of 38.13±12.42 years. The results of multiple linear regression analysis, the AIP and total BMD showed a negative association (β = -0.021, 95%CI:-0.037, -0.006). The curve fitting analysis and threshold effect analysis showed a non-linear relationship between the two variables, and the inflection point of the AIP was found to be -0.61. The total BMD decreased significantly when the AIP reached this value (β = -0.03, 95%CI: -0.04, -0.01). The results of the subgroup analysis showed that AIP and total BMD had a strong negative relationship in participants who were below 45 years old (β = -0.023; 95% CI: -0.041, -0.004), overweight (BMI ≥ 25 kg/m 2 ) (β = -0.022; 95% CI: -0.041, -0.002), had a higher education level (β = -0.025; 95% CI: -0.044, -0.006), and had no partners (β = -0.014; 95% CI: -0.06, -0.009).We found a negative correlation between the AIP and total BMD. Clinicians should pay attention to patients with high AIP, which might indicate a low BMD and has reference significance in preventing osteoporosis.