Causal relationship between tea intake and cardiovascular diseases: A Mendelian randomization study

Area of Science:

• Cardiovascular Science
• Nutritional Epidemiology
• Genetic Epidemiology

Background:

• Existing studies suggest tea consumption may reduce cardiovascular disease (CVD) risk, but conclusions remain inconsistent.
• The precise causal relationship between tea intake and specific CVD subtypes requires further investigation.

Purpose of the Study:

• To systematically investigate the causal effect of tea intake on CVD subtypes using a two-sample Mendelian randomization (MR) analysis.
• To explore the potential mediating role of hypertension in the relationship between tea consumption and CVD.

Main Methods:

• Utilized genetic instruments from a large genome-wide association study (GWAS) for tea intake.
• Employed two-sample Mendelian randomization (MR) analysis, including a two-step approach to assess mediation by hypertension.
• Performed inverse variance weighted (IVW) MR as the primary method, with sensitivity analyses to ensure result robustness.

Main Results:

• Increased tea intake was associated with a reduced risk of hypertension (OR=0.75), heart failure (OR=0.72), and ischemic stroke (OR=0.71).
• Hypertension emerged as a potential mediator in the association between tea drinking and the risk of heart failure and ischemic stroke.
• Sensitivity analyses indicated minimal evidence of pleiotropy, supporting the validity of the findings.

Conclusions:

• This MR study provides genetic evidence supporting a causal link between higher tea intake and reduced risks of hypertension, heart failure, and ischemic stroke.
• Hypertension may act as a mediator, explaining part of the cardioprotective effect of tea.
• Further large-scale randomized controlled trials are warranted to confirm these findings and elucidate the causal impact of tea consumption on CVD.