Hailong Li ¹ Jianfeng Qiu ² Zhe Gao ^3* Chun Li ^4* Jianjun Chu ^5*

• ¹ Fuyang Second People's Hospital, Fuyang, China
• ² School of Artificial Intelligence, Anhui University, Hefei, Anhui Province, China
• ³ Huaibei Miner’s General Hospital, Huaibei, Anhui, China
• ⁴ Third Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
• ⁵ Department of Orthopedics, The Second People's Hospital of Hefei, Hefei, Anhui Province, China

The link between waist-to-height ratio (WHtR) and osteoporosis (OP) remains a contentious issue in the field of medical research. Currently, the available evidence on this association is deemed insufficient. This topic has garnered significant attention and is a focal point of ongoing investigations.A retrospective cross-sectional study was conducted, involving 5746 participants from the National Health and Nutrition Examination Survey. Data on various demographic and clinical parameters, including age, gender, race, poverty income ratio, educational level, smoking status, drinking status, cardiovascular disease, hypertension, diabetes mellitus, hemoglobin A1c, alanine transaminase, aspartate transaminase, serum total bilirubin, serum creatinine, uric acid, blood urea nitrogen, serum sodium, serum phosphorus, total calcium, serum potassium, and serum iron, were collected from all participants. The main analytical methods utilized in this study were multivariable logistic regression, restricted cubic splines, and threshold effect analysis to investigate the association between WHtR and OP.Results: A total of 5746 elderly participants were enrolled, with a median age of 69.3 years. Compared with individuals with lower WHtR Q1 ( ≤ 0.36 to ≤ 0.56), the adjusted OR values for WHtR and OP in Q2 (<0.56 to≤ 0.61), Q3 (<0.61 to≤0.66), and Q4 (<0.66to≤0.94) were 0.63 (95% CI: 0.47-0.85, P = 0.003), 0.53 (95% CI: 0.37-0.76, P < 0.001), and 0.49 (95% CI: 0.35-0.68, P < 0.001), respectively. The association between WHtR and OP exhibited an L-shaped curve (nonlinear, P = 0.008) with an inflection point of roughly 0.57. The OR for the presence of OP was 0.50 (95% CI: 0.31-0.82, P = 0.007) in participants with WHtR < 0.57. There was no association between WHtR and OP in participants with WHtR ≥ 0.57.The association between WHtR and OP showed an L-shaped curve, with an inflection point at around 0.57.