Association between sleep duration and hip fracture risk among the older adults: a cross-sectional study based on the NHANES

Background There has been sharp increase in the incidence of hip fractures (HFs) with the increasing aging globally. However, it remains ambiguous regarding the association between HF risk and sleep duration. This study intended to explore the association between sleep duration and HF risk among the older adults. Methods The study assessed a cohort of 7,540 participants aged at least 60 years old using data from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2010, as well as from 2013 to 2014. Two distinct groups of HF and non-HF were constructed on the basis of their history of HFs. Based on the self-reported sleep duration through a structured questionnaire, multivariate logistic regression analyses were conducted to examine the relationship between sleep duration and HF risk. In addition, restricted cubic splines (RCS) were used to assess linearity. The receiver operating characteristic (ROC) curve was used to explore the threshold of sleep duration for HF risk. Results Among 7540 participants over 60 years of age with mean age of 70.17 ±7.1 years, 129 had HF. Significant differences in sleep duration were observed between the HF and non-HF groups (7.73 ± 1.68 h vs. 7.11 ± 1.42 h; p=0.006). The multivariate analysis was adjusted for sociodemographic, behavioral lifestyle, and comorbidities. A one hour increase in sleep duration was associated with higher odds of having prior hip fractures in unadjusted models （OR=1.36; 1.11, 1.67; p=0.004), minimally adjusted models (OR=1.23; 1.03, 1.48; p=0.025), second adjusted models (OR=1.22; 1.03,1.45; p= 0.024) and fully adjusted models (OR=1.22; 1.03,1.44; p=0.024). The relationship remained consistent across all four models, indicating the correlation of a longer sleep duration with an elevated HF risk. RCS analysis revealed a statistically linear relationship between sleep duration and HF incidence (p-nonlinear=0.244, p-overall<0.01). In addition, the identified threshold of sleep duration linked to HF risk was determined to be 7.5 h among the older adults (AUC=0.611). Conclusion Sleep duration correlates with HF risk among the older adults. Findings in this study inspire that an appropriate sleep duration may reduce the risk of HF among the older adults.