Association of the Zhejiang University index with sleep-related problems in US adults: findings from NHANES 2007-2014

Abstract

Background: This study aims to investigate the precise relationship between the Zhejiang University index (ZJU index) and sleep-related problems.
Methods: This study included 7920 participants from the National Health and Nutrition Examination Surveys conducted between 2007 and 2014. Logistic regression, restricted cubic spline regression, subgroup analyses and receiver operating characteristic (ROC) curve were employed to evaluate the relationship between the ZJU index and sleep-related problems.
Results: After adjusting for all included confounders, the odds ratios (ORs) for sleep disorders, self-reported difficulty falling asleep, and short sleep duration were 1.83 (95%CI: 1.55 to 2.15, P < 0.001), 1.24 (95%CI: 1.12 to 1.37, P < 0.001), 1.17 (95%CI: 1.08 to 1.27, P < 0.001), respectively. A U-shaped nonlinear relationship between the ZJU index and sleep disorders (P-nonlinear = 0.001, point= 37.7) was identified through restricted cubic spline analysis. ROC curve analysis revealed that the ZJU index was superior to single indicators and lipid metabolism indicators in predicting sleep-related problems. Furthermore, it had a high predictive value (area under the curve = 0.710) in elderly women whose sleep disorders were diagnosed.
Conclusion: The ZJU index is strongly associated with sleep-related problems in US adults. Therefore, focusing on high ZJU index levels is useful for early monitoring of sleep-related problems, especially in elderly women.