Genetically predicted causal associations between periodontitis and psychiatric disorders

Shuangshuang Tong; Yanlin Lyu; Wentao Huang; Ruijie Zeng; Rui Jiang; Qizhou Lian; Felix W Leung; Weihong Sha; Hao Chen

doi:10.1136/bmjment-2023-300864

Genetically predicted causal associations between periodontitis and psychiatric disorders

BMJ Ment Health. 2023 Nov 22;26(1):e300864. doi: 10.1136/bmjment-2023-300864.

Authors

Shuangshuang Tong^#^{1

2

3}, Yanlin Lyu^#^{1

3}, Wentao Huang^#^{1

2}, Ruijie Zeng^{1

3}, Rui Jiang^{1

4}, Qizhou Lian^{5

6}, Felix W Leung^{7

8}, Weihong Sha^{9

2

3

4}, Hao Chen^{9

2

3

4}

Affiliations

¹ Department of Gastroenterology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China.
² The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong, China.
³ Shantou University Medical College, Shantou University, Shantou, Guangdong, China.
⁴ School of Medicine, South China University of Technology, Guangzhou, Guangdong, China.
⁵ Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China.
⁶ Cord Blood Bank, Guangzhou Institute of Eugenics and Perinatology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China.
⁷ Sepulveda Ambulatory Care Center, VA Greater Los Angeles Healthcare System, Los Angeles, California, USA chenhao@gdph.org.cn shaweihong@gdph.org.cn felixleung@socal.rr.com.
⁸ School of Medicine, University of California Los Angeles David Geffen School of Medicine, Los Angeles, California, USA.
⁹ Department of Gastroenterology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, Guangdong, China chenhao@gdph.org.cn shaweihong@gdph.org.cn felixleung@socal.rr.com.

^# Contributed equally.

Abstract

Background: Psychiatric disorders have serious harm to individuals' lives with high disease burden. Observational studies reported inconsistent associations between periodontitis and some psychiatric disorders, and the causal correlations between them remain unknown.

Objective: This study aims to explore the causal associations between periodontitis and psychiatric disorders.

Methods: A series of two-sample Mendelian randomisation (MR) analyses were employed using genome-wide association study summary statistics for periodontitis in adults from Gene-Lifestyle Interactions in Dental Endpoints Consortium and 10 psychiatric disorders from Psychiatric Genomics Consortium. Causal effects were primarily estimated using the inverse-variance weighted (IVW) method. Various sensitivity analyses were also conducted to assess the robustness of our results.

Findings: The MR analysis suggested that genetically determined periodontitis was not causally associated with 10 psychiatric disorders (IVW, all p>0.089). Furthermore, the reverse MR analysis revealed that 10 psychiatric disorders had no causal effect on periodontitis (IVW, all p>0.068). We discovered that all the results were consistent in the four MR analytical methods, including the IVW, MR-Egger, weighted median and weighted mode. Besides, we did not identify any heterogeneity or horizontal pleiotropy in the sensitivity analysis.

Conclusions: These results do not support bidirectional causal associations between genetically predicted periodontitis and 10 common psychiatric disorders. Potential confounders might contribute to the previously observed associations.

Clinical implications: Our findings might alleviate the concerns of patients with periodontitis or psychiatric disorders. However, further research was warranted to delve into the intricate relationship between dental health and mental illnesses.

Keywords: Depression & mood disorders; PSYCHIATRY; Schizophrenia & psychotic disorders.

MeSH terms

Adult
Causality
Cost of Illness
Genome-Wide Association Study
Humans
Mental Disorders* / epidemiology
Periodontitis* / epidemiology