Causal relationship between type 2 diabetes and common respiratory system diseases: a two-sample Mendelian...

Area of Science:

• Genetics and Epidemiology
• Metabolic Disorders
• Respiratory Medicine

Background:

• Type 2 diabetes (T2D) often co-occurs with various respiratory diseases, including COPD, asthma, lung cancer, interstitial lung disease, and tuberculosis.
• Existing research on the causal links between T2D and these respiratory conditions is limited.

Purpose of the Study:

• To investigate the potential causal relationships between Type 2 diabetes and several respiratory system diseases.
• Utilize two-sample Mendelian randomization analysis to explore these complex associations.

Main Methods:

• Employed two-sample Mendelian randomization (MR) analysis using publicly available genome-wide association studies.
• Applied the inverse variance-weighted (IVW) method as the primary analysis, with MR Egger's intercept, Cochran's Q test, funnel plots, and leave-one-out analyses for robustness checks.

Main Results:

• A significant negative causal relationship was found between T2D and COPD (OR=0.87, P<0.05), with no significant heterogeneity or pleiotropy.
• A negative causal link between T2D and bronchial asthma was observed (OR=0.85, P<0.05), although heterogeneity was detected.
• A positive causal relationship between T2D and pulmonary tuberculosis was identified (OR=1.24, P<0.05), but pleiotropy was present, indicating potential instability.
• No significant causal associations were found between T2D and lung cancer or interstitial lung disease.

Conclusions:

• Type 2 diabetes appears to have a protective effect against COPD and bronchial asthma, though the latter association requires careful interpretation due to heterogeneity.
• The positive association between T2D and pulmonary tuberculosis warrants further investigation due to observed pleiotropy.
• The study provides novel insights into the complex interplay between metabolic and respiratory health, highlighting the need for further research.