In people with type 2 diabetes, higher coffee consumption is observationally associated with approximately 26% lower mortality and fewer cardiovascular diseases. This is a statistically relevant signal, but not a proven causal relationship. Whether coffee helps prevent type 2 diabetes cannot be assessed on the basis of the available claims.
A large prospective cohort study of 15,486 people with type 2 diabetes (followed for an average of 18.5 years) found that people who drank more coffee had a 26% lower chance of dying than people who drank little coffee (hazard ratio 0.74; 95% confidence interval 0.63-0.86). People who increased their coffee consumption after their diabetes diagnosis also had lower mortality. This suggests a favourable association, but this is an observational study: causality has not been proven (PMID 37076174).
The same study showed that higher coffee consumption was also associated with fewer cardiovascular diseases in people with type 2 diabetes. The association was statistically significant, although the exact figures for this specific outcome were not reported separately. Cardiovascular disease is one of the most important complications of diabetes, so this is a relevant signal.
By comparison, sugar-sweetened beverages showed the opposite pattern in the same study. Drinking more sugar-sweetened beverages was associated with a 20% higher risk of all-cause mortality (HR 1.20), a 25% higher risk of cardiovascular disease (HR 1.25) and a 29% higher risk of cardiovascular mortality (HR 1.29). Replacing sugar-sweetened beverages with coffee was consistently linked to a lower risk of mortality (PMID 37076174).
An important caveat: all of these associations are observational. People who drink a lot of coffee may also have a healthier lifestyle in other ways, and this can influence the outcomes. Randomised trials that could demonstrate causality are lacking here.
The available claims concern mortality and cardiovascular disease in people who already have type 2 diabetes. This source file does not include any controlled data on the prevention of type 2 diabetes in healthy individuals. The question of whether coffee helps prevent diabetes cannot be answered on the basis of the claims provided.
All claims are derived from one prospective cohort study (PMID 37076174) and one epidemiological review (PMID 38879999). No randomised controlled trials or meta-analyses were used as direct sources. The strength of evidence is therefore moderate for the mortality outcomes, but causality has not been demonstrated.