Data_Sheet_1_Association of body mass index with rapid eye movement sleep behavior disorder in Parkinson’s disease.docx

BackgroundThe association between body mass index (BMI) and rapid eye-movement (REM) sleep-related behavioral disorder (RBD) in Parkinson’s disease (PD) remains unknown. Our study was to investigate the association of BMI with RBD in PD patients.
MethodsIn this cross-sectional study, a total of 1,115 PD participants were enrolled from Parkinson’s Progression Markers Initiative (PPMI) database. BMI was calculated as weight divided by height squared. RBD was defined as the RBD questionnaire (RBDSQ) score with the cutoff of 5 or more assessed. Univariable and multivariable logistic regression models were performed to examine the associations between BMI and the prevalence of RBD. Non-linear correlations were explored with use of restricted cubic spline (RCS) analysis. And the inflection point was determined by the two-line piecewise linear models.
ResultsWe identified 426 (38.2%) RBD. The proportion of underweight, normal, overweight and obese was 2.61, 36.59, 40.36, and 20.44%, respectively. In the multivariate logistic regression model with full adjustment for confounding variables, obese individuals had an odds ratio of 1.77 (95% confidence interval: 1.21 to 2.59) with RBD compared with those of normal weight. In the RCS models with three knots, BMI showed a non-linear association with RBD. The turning points of BMI estimated from piecewise linear models were of 28.16 kg/m2, 28.10 kg/m2, and 28.23 kg/m2 derived from univariable and multivariable adjusted logistic regression models. The effect modification by depression on the association between BMI and RBD in PD was also found in this study. Furthermore, the sensitivity analyses linked with cognition, education, and ethnic groups indicated the robustness of our results.
ConclusionThe current study found a significant dose–response association between BMI and RBD with a depression-based difference in the impact of BMI on RBD in PD patients.

背景
帕金森病（Parkinson’s Disease, PD）患者的体质量指数（Body Mass Index, BMI）与快速眼动睡眠行为障碍（Rapid Eye-Movement Sleep-Related Behavioral Disorder, RBD）之间的关联尚不明确。本研究旨在探讨帕金森病患者体质量指数与RBD的关联。

方法
本项横断面研究共纳入来自帕金森病进展标志物倡议（Parkinson’s Progression Markers Initiative, PPMI）数据库的1115名帕金森病参与者。体质量指数按体重除以身高平方计算。RBD的定义为快速眼动睡眠行为障碍问卷（RBDSQ）得分≥5分。采用单因素及多因素logistic回归模型分析BMI与RBD患病率的关联。通过限制性立方样条（Restricted Cubic Spline, RCS）分析探索非线性相关关系，并通过两分段线性模型确定拐点。

结果
本研究共纳入1115名帕金森病参与者，其中426名（38.2%）符合RBD诊断。体质量过低、体质量正常、超重及肥胖参与者的占比分别为2.61%、36.59%、40.36%及20.44%。在对混杂变量进行全面校正的多因素logistic回归模型中，肥胖参与者相较于体质量正常者，其发生RBD的比值比为1.77（95%置信区间：1.21~2.59）。在设置3个节点的限制性立方样条模型中，BMI与RBD呈非线性相关关系。通过单因素及多因素校正logistic回归模型估算的BMI拐点分别为28.16 kg/m²、28.10 kg/m²及28.23 kg/m²。本研究还发现，抑郁对帕金森病患者BMI与RBD的关联存在效应修饰作用。此外，针对认知水平、受教育程度及种族群体的敏感性分析证实了本研究结果的稳健性。

结论
本研究结果显示，帕金森病患者的BMI与RBD之间存在显著的剂量-反应关联，且BMI对RBD的影响存在基于抑郁状态的差异。