Traditional parametric (t, F) and nonparametric (Mann-Whitney-Wilcoxon U, Kruskal-Wallis H) statistics are sensitive to heterogeneity of variance (heteroscedasticity). Moreover, there are theoretical reasons to expect, and empirical results to document, the existence of heteroscedasticity in clinical data. Transformations to reduce heteroscedasticity are problematic. This article reviews the literature on robust methods that are available and that should be widely used to control rate of Type I error and maintain power. No one robust method is ideal for all situations, but such methods are superior to the traditional tests. Specific recommendations are made for application under various conditions of heteroscedasticity.
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http://dx.doi.org/10.1037//0022-006x.68.1.155 | DOI Listing |
J Surg Res
January 2025
School of Medicine, Tongji University, Shanghai, China; Department of Health Statistics, Navy Medical University, Shanghai, China. Electronic address:
Introduction: Body mass index (BMI) has been implicated in various cardiovascular conditions, but its association with peripheral artery disease (PAD) in both real-world and genetic studies have been contentious and debated.
Methods: This study enrolled 6707 individuals from the National Health and Nutrition Examination Survey database to investigate the association between BMI and the risk of PAD. The weighted logistic regression, restricted cubic spline, and subgroup analysis were performed using real-world data.
Int J Rheum Dis
January 2025
Department of Orthopedics, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei, China.
Objective: Osteoarthritis is a common joint disease caused by a variety of risk factors, and it has been found that many biochemical markers are abnormal in peripheral blood and urine of patients with OA. The aim of this study was to elucidate the causal relationship between biomarkers associated with these processes and OA using Mendelian randomization (MR) analysis.
Method: The inverse variance weighted (IVW) approach to MR was primarily used to explore causal associations between exposures and outcomes using publicly available genetic variants from large genome-wide association studies (GWAS).
Mol Brain
January 2025
Xuanwu Hospital, China-America Institute of Neurology, Capital Medical University, No. 45, Changchun Street, Xicheng District, Beijing, China.
It is unclear how steroid hormones contribute to stroke, and conducting randomized controlled trials to obtain related evidence is challenging. Therefore, Mendelian randomization (MR) technique was employed in this study to examine this association. Through genome-wide association meta-analysis, the genetic variants of steroid hormones, including testosterone/17β-estradiol (T/E2) ratio, aldosterone, androstenedione, progesterone, and hydroxyprogesterone, were acquired as instrumental variables.
View Article and Find Full Text PDFThromb J
January 2025
Department of Vascular Surgery, Huadong Hospital, Fudan University, Shanghai, 200040, China.
Background: Venous thromboembolism (VTE) is a common vascular disease with a significant global burden, influenced by multiple factors, such as genetic, environmental, and immune components. Immune responses and shifts in immune cell profiles are closely linked to the development and progression of VTE, yet current studies are limited by confounding factors and reverse causation. To address these limitations, this study uses Mendelian randomization to explore the causal relationship between immune cell traits and VTE, aiming to provide insights into underlying mechanisms.
View Article and Find Full Text PDFBMC Cardiovasc Disord
January 2025
Department of Respiratory and Critical Care Medicine, The Second Hospital of Hebei Medical University, 215 Heping West Road, Shijiazhuang, Hebei, China.
Background: Pulmonary arterial hypertension (PAH) is a severe and progressive cardiovascular disease. While potential links between clonal hematopoiesis (CH) and cardiovascular diseases have been identified, the causal relationship between CH and PAH remains unclear. This study aims to investigate the causal effect of CH on the risk of PAH using a two-sample Mendelian randomization (MR) approach.
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