Changes in coffee intake and subsequent risk of type 2 diabetes: three large cohorts of US men and women.
OBJECTIVE
Coffee and tea consumption has been associated with a lower type 2 diabetes risk but little is known about how changes in coffee and tea consumption influence subsequent type 2 diabetes risk. We examined the associations between 4 year changes in coffee and tea consumption and risk of type 2 diabetes in the subsequent 4 years.


METHODS
We prospectively followed 48,464 women in the Nurses' Health Study (NHS; 1986-2006), 47,510 women in NHS II (1991-2007) and 27,759 men in the Health Professionals Follow-up Study (HPFS; 1986-2006). Diet was assessed every 4 years using a validated food-frequency questionnaire. Self-reported cases of incident type 2 diabetes were validated by supplementary questionnaires.


RESULTS
During 1,663,319 person-years of follow-up, we documented 7,269 cases of incident type 2 diabetes. Participants who increased their coffee consumption by more than 1 cup/day (median change = 1.69 cups/day) over a 4 year period had an 11% (95% CI 3%, 18%) lower risk of type 2 diabetes in the subsequent 4 years compared with those who made no changes in consumption. Participants who decreased their coffee intake by more than 1 cup/day (median change = -2 cups/day) had a 17% (95% CI 8%, 26%) higher risk for type 2 diabetes. Changes in tea consumption were not associated with type 2 diabetes risk.


CONCLUSIONS
Our data provide novel evidence that increasing coffee consumption over a 4 year period is associated with a lower risk of type 2 diabetes, while decreasing coffee consumption is associated with a higher risk of type 2 diabetes in subsequent years.
Department of Nutrition, Harvard School of Public Health, 655 Huntington Ave, Boston, MA, 02115, USA.
Shilpa N
SN
Bhupathiraju
An
A
Pan
JoAnn E
JE
Manson
Walter C
WC
Willett
Rob M
RM
van Dam
Frank B
FB
Hu
D000328:Adult; D015992:Body Mass Index; D003069:Coffee; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000209:etiology*; D004327:Drinking Behavior / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D011795:Surveys and Questionnaires; D014481:United States
D003069:Coffee