Causal relationship between tea intake and bone mineral density at different ages ̶ A Mendelian randomization study

Area of Science:

• Nutrigenomics
• Bone Health Research
• Epidemiology

Background:

• Bone mineral density (BMD) is a critical indicator for osteoporosis and fracture risk.
• Dietary tea consumption influences BMD variations, but the underlying mechanisms remain unclear.
• Understanding the causal link between tea intake and BMD is essential for public health.

Purpose of the Study:

• To investigate the causal relationship between tea consumption and BMD using a two-sample Mendelian randomization (MR) approach.
• To determine if the effect of tea intake on BMD differs across various age groups.

Main Methods:

• A two-sample MR analysis was conducted using genetic data for tea intake (31 SNPs) from the UK Biobank (n=447,485).
• BMD data (total body and age-specific) were obtained from the Lifelong Genetic Cohort Study (n=66,628).
• Causal inference was performed using MR-Egger, inverse variance weighting (IVW), weighted median, and weighted mode methods.

Main Results:

• Tea consumption demonstrated a positive causal effect on total body BMD.
• This positive association was significant only in the 45-60 age group.
• No significant genetic pleiotropy or heterogeneity was detected, supporting the robustness of the findings.

Conclusions:

• Tea intake has a positive causal impact on overall BMD.
• The beneficial effect of tea on BMD is age-specific, primarily benefiting the 45-60 age demographic.
• These findings suggest tea consumption may play a role in mitigating osteoporosis and fracture risk in middle-aged adults.