Body Mass Index-related genetic factors and COPD imaging phenotypes

Area of Science:

• Pulmonary Medicine
• Genetics
• Radiology

Background:

• Low body mass index (BMI) is linked to emphysema, while obesity is associated with airway disease in Chronic Obstructive Pulmonary Disease (COPD).
• The precise mechanisms underlying these associations remain unclear.
• Understanding the genetic underpinnings of BMI may elucidate its role in COPD pathogenesis.

Purpose of the Study:

• To investigate the relationship between genetic variants associated with BMI and imaging phenotypes of emphysema and airway disease.
• To determine if a polygenic score for BMI can predict lung imaging characteristics in COPD and general populations.

Main Methods:

• Generated a polygenic score for BMI (PGSBMI) by aggregating genetic variants from genome-wide association studies.
• Assessed associations between PGSBMI and quantitative CT-based emphysema and airway wall thickness (AWT) measures.
• Utilized meta-analysis to combine results from COPD-enriched and community-based cohorts.

Main Results:

• A higher PGSBMI was associated with less emphysema, both quantitatively (reduced low attenuation areas and lung density histogram values) and visually.
• Increased airway wall thickness (AWT), measured by quantitative CT parameters, was associated with a higher PGSBMI.
• Visual assessment revealed that a higher PGSBMI correlated with reduced emphysema severity and increased airway wall thickening in specific cohorts.

Conclusions:

• Genetic determinants of BMI are associated with both reduced emphysema and increased airway wall thickness.
• These findings suggest that genetic factors influencing BMI play a role in the development of emphysema and airway remodeling in COPD.
• The study highlights the complex interplay between genetics, BMI, and lung disease phenotypes.