Winje Eirin, Torgalsbøen Anne-Kari, Brunborg Cathrine, Stedal Kristin
Division of Mental Health and Addiction, Regional Department for Eating Disorders, Oslo universitetssykehus HF, Postboks 4956, Nydalen, 0424 Oslo, Norway.
Department of Psychology, University of Oslo, P.O. Box 1039, 0317 Oslo, Norway.
J Eat Disord. 2017 Jan 10;5:2. doi: 10.1186/s40337-016-0131-1. eCollection 2017.
Outcomes from studies on season of birth bias in eating disorders have been inconsistent. This inconsistency has been explained by differences in methodologies resulting in different types of effect sizes. The aim of the current study was to facilitate comparison by using the same methodology on samples from two studies with differing conclusions.
The statistical analyses used in each study were applied to the samples from the other study and the resulting effect sizes, Cramêr's V and odds ratio (OR), were compared and discussed.
For both studies, the Cramêr's Vs ranged between 0.03 and 0.08 and the OR ranged between 0.85 and 1.31. According to common conventions, Cramêr's Vs below 0.10 and ORs below 1.44 are considered small.
As a marker of one or more potential risk factors, the observed effects are considered to be small. When reanalysed allowing for direct comparisons, studies with contrasting conclusions converge towards an absence of support for a season of birth bias for patients with AN.
关于饮食失调中出生季节偏差的研究结果并不一致。这种不一致被解释为方法上的差异导致了不同类型的效应量。本研究的目的是通过对两项结论不同的研究样本使用相同的方法来促进比较。
将每项研究中使用的统计分析应用于另一项研究的样本，并对所得的效应量、克莱默V系数和比值比（OR）进行比较和讨论。
两项研究中，克莱默V系数在0.03至0.08之间，比值比在0.85至1.31之间。根据通用标准，低于0.10的克莱默V系数和低于1.44的比值比被视为小效应量。
作为一个或多个潜在风险因素的标志，观察到的效应被认为是小的。当进行重新分析以允许直接比较时，结论相反的研究趋向于不支持神经性厌食症患者存在出生季节偏差。
