Previous studies have indicated that acute administration of caffeine decreases insulin sensitivity and impairs glucose tolerance.
In this study, physicians from Mexico and the United States examined the relationship between coffee consumption, the consumption of other caffeinated beverages, and the incidence of type 2 diabetes mellitus.
The team followed 41,934 men from 1986 to 1998, and 84,276 women from 1980 to 1998.
These participants did not have diabetes, cancer, or cardiovascular disease at baseline.
|There was an inverse association between coffee intake and type 2 diabetes.|
|Annals of Internal Medicine|
The team assessed coffee consumption using validated questionnaires.
During the course of the study there were 1333 new cases of type 2 diabetes in men and 4085 in women.
The physicians identified an inverse association between coffee intake and type 2 diabetes, once adjustment was made for age, body mass index, and other risk factors.
The team calculated the multivariate relative risks for diabetes according to regular coffee consumption categories (0, <1, 1 to 3, 4 to 5, or 6 cups per day):
- For men the risks were 1.00, 0.98, 0.93, 0.71, and 0.46, respectively.
- For women the risks were 1.00, 1.16, 0.99, 0.70, and 0.71, respectively.
For decaffeinated coffee, the team compared individuals who drank 4 cups or more per day with nondrinkers. Relative risks were 0.74 for men and 0.85 for women.
In addition, they found that total caffeine intake from coffee and other sources was associated with a lower risk for diabetes in both men and women.
Dr Eduardo Salazar-Martinez's team concluded, "These data suggest that long-term coffee consumption is associated with a statistically significantly lower risk for type 2 diabetes".