Association between periodontitis and breast cancer: two-sample Mendelian randomization study

Area of Science:

• Genetics
• Epidemiology
• Oral Health

Background:

• Observational studies suggest a link between periodontitis and breast cancer.
• The causal nature of this association remains unclear.

Purpose of the Study:

• To investigate the causal relationship between periodontitis and breast cancer using Mendelian randomization (MR).

Main Methods:

• Two-sample bidirectional MR analysis utilizing publicly available genome-wide association studies (GWAS) statistics.
• Primary analysis employed the inverse-variance weighted (IVW) method.
• Sensitivity analyses included weighted median, MR-Egger regression, and MR-pleiotropy residual sum and outlier (MR-PRESSO) to assess pleiotropy.

Main Results:

• No evidence of a causal effect of periodontitis on breast cancer (IVW OR=0.99, P=0.14).
• No evidence of a causal effect of breast cancer on periodontitis (IVW OR=0.95, P=0.83).
• Sensitivity analyses indicated that horizontal pleiotropy was unlikely to bias the causal estimates.

Conclusions:

• The MR analysis does not support a causal relationship between periodontitis and breast cancer.
• These findings contrast with some observational studies, highlighting the importance of MR in establishing causality.
• This research provides a reference for clinicians and deepens the understanding of periodontitis's relationship with systemic diseases.