Causal Inference of Different Smoke Exposure Statuses and Influenza Risk: Insights From a Mendelian Randomization...

Area of Science:

• Epidemiology
• Genetic Epidemiology
• Public Health

Background:

• Observational studies suggest smoking exposure may increase influenza risk.
• The specific impact of different smoking statuses on influenza susceptibility requires further investigation.
• Mendelian randomization (MR) can elucidate causal relationships between exposures and outcomes.

Purpose of the Study:

• To investigate the causal effect of current tobacco use, past smoking history, and household smoking exposure on influenza infection risk.
• To differentiate the impact of various smoking exposures on influenza susceptibility.
• To utilize MR analysis for robust causal inference.

Main Methods:

• Summary-level data from FinnGen Consortium R11 and Neale Lab were used.
• Mendelian randomization analysis employed inverse variance weighting, MR-Egger, and weighted median methods.
• Heterogeneity and pleiotropy were assessed using Cochran's Q test, MR-PRESSO, and MR-Egger intercept tests.

Main Results:

• Current tobacco smoking causally increased the risk of influenza infection (OR=2.032, p<0.001).
• No significant causal association was found for past smoking history (OR=1.108, p=0.779).
• No significant causal association was found for household smoking exposure (OR=1.127, p=0.939).

Conclusions:

• A significant causal link exists between current tobacco smoking and elevated influenza infection risk.
• Past smoking and household smoking exposure did not show a significant causal association with influenza risk.
• Findings underscore the need to consider specific smoking statuses in influenza prevention strategies.