A Principled Framework for Mendelian Randomization in Oral Health Research.

Area of Science:

• Epidemiology
• Genetics
• Biostatistics

Background:

• Observational studies often struggle with confounding and reverse causation, limiting causal inference.
• Mendelian randomization (MR) has emerged as a powerful tool to address these limitations.
• Understanding MR's core assumptions is crucial for valid causal discovery.

Purpose of the Study:

• To review the fundamental assumptions of Mendelian randomization (MR) for credible causal inference.
• To provide a clear explanation of MR methodology for non-statistical audiences.
• To discuss specific applications and considerations of MR in oral health research, focusing on periodontitis.

Main Methods:

• Review of key assumptions required for valid Mendelian randomization analyses.
• Explanation of how genetic variants act as instrumental variables.
• Discussion of potential violations of MR assumptions and their impact on results.

Main Results:

• MR leverages the random allocation of genetic variants to establish causal relationships.
• Violations of core MR assumptions can lead to biased and implausible causal conclusions.
• The manuscript provides guidance on assessing MR study credibility and reporting.

Conclusions:

• Mendelian randomization is a valuable method for causal inference when assumptions are met.
• Careful application and critical assessment are necessary for reliable MR findings, particularly in specialized fields like oral health.
• The article equips researchers to critically evaluate and conduct MR studies effectively.