Association between subtypes of diabetes and special sensations: A 2-sample Mendelian randomization study

Area of Science:

• Endocrinology
• Otolaryngology
• Genetics

Background:

• Diabetes mellitus, encompassing type 1 (T1D) and type 2 (T2D), is a prevalent chronic condition.
• While diabetes's impact on vision is known, its effects on other special senses (hearing, olfaction, balance) are less understood.

Purpose of the Study:

• To investigate the potential causal relationships between T1D and T2D and specific sensory disorders using a robust genetic approach.
• To assess the association between diabetes subtypes and vestibular dysfunction, hearing loss (sensorineural and conductive), and olfactory dysfunction.

Main Methods:

• Employed a 2-sample Mendelian randomization (MR) approach utilizing large-scale genome-wide association studies datasets for diabetes subtypes and sensory disorders.
• Applied multiple MR analysis methods including inverse variance weighting (IVW), MR-Egger, and MR-PRESSO to ensure result validity.
• Conducted validation studies to confirm initial findings and assess robustness.

Main Results:

• MR analysis revealed no statistically significant causal associations between T1D or T2D and the investigated sensory disorders.
• An initial signal suggesting a potential increased risk of conductive hearing loss with T1D was not supported by validation analyses.
• No significant evidence of horizontal pleiotropy or heterogeneity was detected, strengthening the reliability of the findings.

Conclusions:

• This comprehensive MR study provides no evidence for a causal link between diabetes subtypes and impairments in special senses.
• The previously suggested association between T1D and conductive hearing loss is not supported by this genetic evidence.
• Further research is warranted to explore the complex interplay between diabetes, sensory function, and potential management strategies.