Differential effects of coffee on the risk of type 2 diabetes according to meal consumption in a French cohort of women: the E3N/EPIC cohort study.
BACKGROUND
Coffee consumption has been associated with a lower risk of diabetes, but little is known about the mechanisms responsible for this association, especially related to the time when coffee is consumed.


OBJECTIVE
We examined the long-term effect of coffee, globally and according to the accompanying meal, and of tea, chicory, and caffeine on type 2 diabetes risk.


METHODS
This was a prospective cohort study including 69,532 French women, aged 41-72 y from the E3N/EPIC (Etude Epidémiologique auprès de Femmes de la Mutuelle Générale de l'Education Nationale/European Prospective Investigation into Cancer and Nutrition) cohort study, without diabetes at baseline. Food and drink intakes per meal were assessed by using a validated diet-history questionnaire in 1993-1995.


RESULTS
During a mean follow-up of 11 y, 1415 new cases of diabetes were identified. In multivariable Cox regression models, the hazard ratio in the highest category of coffee consumption [> or =3 cups (375 mL)/d] was 0.73 (95% CI: 0.61, 0.87; P for trend < 0.001), in comparison with no coffee consumption. This inverse association was restricted to coffee consumed at lunchtime (hazard ratio: 0.66; 95% CI: 0.57, 0.76) when comparing >1.1 cup (125 mL)/meal with no intake. At lunchtime, this inverse association was observed for both regular and decaffeinated coffee and for filtered and black coffee, with no effect of sweetening. Total caffeine intake was also associated with a statistically significantly lower risk of diabetes. Neither tea nor chicory consumption was associated with diabetes risk.


CONCLUSIONS
Our data support an inverse association between coffee consumption and diabetes and suggest that the time of drinking coffee plays a distinct role in glucose metabolism.
Department of Social Medicine, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
Daniela S
DS
Sartorelli
Guy
G
Fagherazzi
Beverley
B
Balkau
Marina S
MS
Touillaud
Marie-Christine
MC
Boutron-Ruault
Blandine
B
de Lauzon-Guillain
Françoise
F
Clavel-Chapelon
D001786:Blood Glucose / Q000378:metabolism; D002110:Caffeine; D028241:Camellia sinensis; D018651:Cichorium intybus; D003069:Coffee; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000517:prevention & control*; D004032:Diet; D004034:Diet Surveys; D005247:Feeding Behavior; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D028321:Plant Preparations / Q000627:therapeutic use*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013997:Time Factors
D001786:Blood Glucose; D003069:Coffee; D028321:Plant Preparations; D002110:Caffeine