A comprehensive Italian cohort study reveals that drinking several cups of coffee daily does not significantly increase the risk of developing type 2 diabetes over a decade, challenging assumptions about caffeine’s long-term metabolic effects.
A long-running Italian cohort study has found no clear evidence that drinking several cups of coffee a day raises the risk of type 2 diabetes over 10 years, even though caffeine can temporarily affect how the body handles glucose.
The research, published in Nutrition, Metabolism and Cardiovascular Diseases, analysed data from the PAMELA study in Monza, Italy, and compared coffee consumers with non-consumers. Participants who reported drinking at least two to three cups a day did not show a significant increase in new cases of type 2 diabetes or impaired fasting glucose, a condition in which blood sugar is higher than normal but not yet in the diabetic range.
The findings add to a body of earlier research suggesting that habitual coffee drinking is, at worst, largely neutral for diabetes risk and may even be linked with lower risk in some populations. A 2014 meta-analysis in Diabetes Care, drawing on more than a million people, found an inverse association between both caffeinated and decaffeinated coffee and type 2 diabetes, while earlier cohort studies, including work in postmenopausal women, reported similar protective patterns. The new study is more cautious: the authors note that their non-coffee group was small and that the estimates were imprecise, so a modest difference in risk cannot be ruled out.
The researchers also emphasised that the study was observational and relied on self-reported coffee intake. It did not measure tea, decaffeinated coffee or other caffeinated drinks, and it could not account for differences in caffeine content, brew type or changes in diet over time. Even so, after a decade of follow-up, the data did not support the idea that regular coffee drinking, at least at the levels studied, meaningfully worsens long-term glucose metabolism in the general population.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
