long term coffee (caffeine) drinking and mortality

Last edited 09/2022

Coffee drinking and mortality:

  • to examine the association between coffee and mortality, the authors performed a cohort study with a sample of participants in the National Institutes of Health (NIH)-American Association of Retired Persons Diet and Health Study (1)
    • study involved more than 400 000 participants followed for a median of 13.6 years, during which over 52 000 died
    • coffee consumption was assessed once at baseline using a food frequency questionnaire with 10 possible categories, ranging from zero to six or more cups per day, with an additional question about the type of coffee (caffeinated vs decaffeinated)
    • findings
      • although coffee consumption was associated with increased mortality in age-adjusted analyses, in fully adjusted analyses, there was an inverse, dose-response relationship between coffee consumption and mortality
      • among men
        • those who drank between two and three cups per day had a 10% decreased risk
        • those who drank between four and five cups per day had a 12% decreased risk
        • those who drank six or more cups per day had again 10% decreased risk of mortality compared to non-coffee drinkers
      • among women
        • those who drank between two and three cups per day had a 13% decreased risk
        • those who drank between four and five cups per day had a 16% reduced risk
        • those who drank six or mor cups of coffee per day had a 15% decreased risk of mortality compared to non-coffee drinkers

      • results were found after adjusting for many confounders, including age, body mass index, race, level of education, lifestyle factors (eg, current and prior smoking) and comorbidities
      • also found a similar inverse association for analyses including only never-smoking participants or participants with very good to excellent health at baseline (ie if a person had very good/excellent health at baseline then there was a reduced risk of mortality compared to those who were not of very good/excellent health)
      • coffee consumption was associated with reduced mortality across several disease categories (including heart disease, stroke, injuries and accidents and diabetes)

    • but....
      • different types of coffees or preparation methods may affect the results, although mortality appears to be reduced among drinkers of both caffeinated and decaffeinated coffee
      • effects of coffee may also be different for people who have experienced a prior cardiovascular event - people with these histories were excluded from the cohort
      • ubiquity of this association might suggest that coffee is only a marker for healthier people
      • unmeasured psychosocial and environmental factors associated with coffee consumption might play a role in this association

      • the authors state '..given the observational nature of our study, it is not possible to conclude that the inverse relationship between coffee consumption and mortality reflects cause and effect.....in summary, this large prospective cohort study showed significant inverse associations of coffee consumption with deaths from all causes and specifically with deaths due to heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections. Our results provide reassurance with respect to the concern that coffee drinking might adversely affect health..' (1)

Other well-designed cohort studies have found an inverse association between long-term coffee consumption and the risk of all-cause mortality in different populations (2,3)

A more recent large prospective cohort study showed (4):

  • consumers of various amounts of unsweetened coffee (>0-1.5, >1.5-2.5, >2.5-3.5, >3.5-4.5 & >4.5 drinks/d) had lower risks for all-cause mortality vs nonconsumers, the association between artificially sweetened coffee & mortality was less consistent

A further study showed (5):

  • decaffeinated, ground, and instant coffee, particularly at 2-3 cups/day, were associated with significant reductions in incident CVD and mortality. Ground and instant but not decaffeinated coffee was associated with reduced arrhythmia

Reference: