Mendelian randomization (MR) is a flexible analytical tool that has been widely applied to strengthen causal inference in observational epidemiology and is now gaining attention in many areas including periodontal research. The interpretation of results drawn from MR is based on a series of assumptions, which can be unrealistic or difficult to meet faithfully in some settings. However, we argue that with care, this does not necessarily prevent valuable deployment of the approach. We argue that clarity of presentation as well as careful assessment of specific analytical conditions is a fundamental part of all MR analyses. To that end, awareness of its limitations should also guide the design of MR investigations and the presentation of results rather than rule out its use altogether. Notably, considerations similar to those known to be important in conventional epidemiological settings apply to MR. While MR studies are valuable in their contrast to other study limitations, the application of this technique must be carefully cross‐examined. Specific considerations include possible confounders, recruitment strategy and phenotypic measurement and differential analysis properties across studies. In the case of periodontal research, current MR applications are limited by the available evidence base for genetic contributions to periodontitis; however, this sets a specific scene for the strategic use of MR and shines light on a need for greater research emphasis on the genetics of the condition and intermediaries. This article provides a perspective on the uses and inherent limitations of MR studies and the importance of adhering to basic epidemiological principles when designing them.

中文翻译：

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牙周炎的孟德尔随机化研究：了解应用环境中的益处和自然限制


孟德尔随机化 （MR） 是一种灵活的分析工具，已被广泛用于加强观察流行病学中的因果推断，现在在包括牙周研究在内的许多领域都受到关注。对 MR 结果的解释基于一系列假设，在某些情况下，这些假设可能不切实际或难以忠实地满足。然而，我们认为，只要谨慎，这并不一定会阻止该方法的宝贵部署。我们认为，清晰的表现以及对特定分析条件的仔细评估是所有 MR 分析的基本组成部分。为此，对其局限性的认识也应指导 MR 调查的设计和结果的呈现，而不是完全排除其使用。值得注意的是，与常规流行病学环境中已知的重要考虑因素类似的考虑因素适用于 MR。虽然 MR 研究与其他研究局限性相比很有价值，但必须仔细交叉检查该技术的应用。具体考虑因素包括可能的混杂因素、募集策略和表型测量以及研究之间的差异分析特性。在牙周病研究的情况下，目前的 MR 应用受到遗传对牙周炎的遗传影响的现有证据基础的限制;然而，这为 MR 的战略使用设定了特定的场景，并阐明了需要更加强调疾病遗传学和中介学的研究。本文提供了关于 MR 研究的用途和内在局限性以及在设计时遵守基本流行病学原则的重要性的观点。