Heavier smoking increases coffee consumption: findings from a Mendelian randomization analysis

Area of Science:

• Behavioral genetics
• Nutritional epidemiology
• Substance use research

Background:

• Observational studies suggest a link between cigarette and coffee consumption.
• Smokers metabolize caffeine faster, implying smoking may influence caffeine intake.

Purpose of the Study:

• To investigate the causal relationship between cigarette consumption and coffee/tea intake.
• To utilize Mendelian randomization to assess genetic influences on smoking and beverage consumption.

Main Methods:

• Mendelian randomization analyses were performed across three large cohorts: UK Biobank, HUNT, and CGPS.
• The rs16969968 variant served as a proxy for smoking heaviness.
• Genetic variants for coffee consumption (rs4410790, rs2472297) were used in specific cohorts.

Main Results:

• Each additional daily cigarette was associated with increased coffee consumption (0.10 cups/day).
• Carrying the rs16969968 variant (higher smoking) strongly correlated with increased coffee intake (0.16 cups/day).
• No clear association was found between smoking-related variants and coffee/tea intake in non-smokers.

Conclusions:

• Increased cigarette consumption causally increases coffee intake.
• This effect may be explained by accelerated caffeine metabolism in smokers or behavioral links.
• Findings support a causal link between smoking and higher coffee consumption.