Causal Relationship Between Air Pollutants and Blood Pressure Phenotypes: A Mendelian Randomization Study

Area of Science:

• Environmental Health
• Cardiovascular Epidemiology
• Genetic Epidemiology

Background:

• Hypertension is a global health concern with potential links to environmental factors like air pollution.
• Previous studies suggested associations between air pollutants and hypertension, but causal evidence was lacking.

Purpose of the Study:

• To investigate the causal relationships between five specific air pollutants and four blood pressure phenotypes.
• To establish causality using two-sample Mendelian randomization.

Main Methods:

• Utilized two-sample Mendelian randomization (MR) analyses with genome-wide association studies (GWAS) data.
• Employed inverse variance weighting (IVW) as the primary analysis method.
• Conducted sensitivity analyses including MR-Egger regression, weighted median, and leave-one-out methods to assess pleiotropy and heterogeneity.

Main Results:

• PM10 showed a positive causal association with hypertension (OR: 1.49) and systolic blood pressure (β: 1.89).
• PM2.5 demonstrated a positive causal association with hypertension (OR: 1.26).
• NO2 exhibited a negative causal association with systolic blood pressure (β: -1.71).
• No significant pleiotropic bias was detected; heterogeneity was observed in most associations.

Conclusions:

• Elevated PM2.5 and PM10 levels causally increase hypertension risk and systolic blood pressure.
• NO2 may act as a protective factor against elevated systolic blood pressure.
• Maintaining good air quality is crucial for hypertension prevention and reducing disease burden.