Causal relationship between chronic obstructive pulmonary disease and BMD at different sites: A bidirectional...

Area of Science:

• Genetics
• Pulmonology
• Orthopedics

Background:

• Observational studies suggest a link between chronic obstructive pulmonary disease (COPD) and osteoporosis (OP).
• The causal relationship between COPD and bone mineral density (BMD) reduction at various skeletal sites remains unclear.
• Genetic causality requires investigation to understand the underlying mechanisms.

Purpose of the Study:

• To investigate the potential causal relationship between COPD and BMD at different anatomical locations using genetic data.
• To determine if COPD genetically influences BMD or if reduced BMD genetically predisposes individuals to COPD.

Main Methods:

• Utilized genome-wide association study (GWAS) data for COPD and BMD.
• Employed Mendelian randomization (MR) analysis with single nucleotide polymorphisms (SNPs) as instrumental variables.
• Applied inverse variance weighted, MR-Egger, and weighted median methods, alongside heterogeneity and pleiotropy tests.

Main Results:

• COPD showed a significant negative causal association with heel BMD (OR=0.978, P=0.0003).
• No significant causal effect of COPD on lumbar spine (LS), femoral neck (FN), or forearm (FA) BMD was observed.
• Reverse MR analysis indicated no significant causal effect of BMD at any site on COPD risk.

Conclusions:

• COPD causally increases the risk of decreased heel BMD.
• There is no genetic evidence that reduced BMD at various sites increases the risk of developing COPD.
• Findings highlight a specific genetic link between COPD and heel bone density, warranting further clinical attention.