a1 Health Behaviors, Cancer Prevention and Population Sciences, Roswell Park Cancer Institute, Buffalo, NY, USA
a2 School of Community Health, Portland State University, 506 Mill Street, 450-A Urban Center, Portland, OR 97201, USA
a3 School of Medicine, University of Puerto Rico, San Juan, Puerto Rico
Objective To study prospectively the association of coffee intake with incident diabetes in the Puerto Rico Heart Health Program cohort, comprising 9824 middle-aged men (aged 35–79 years).
Methods Of 9824 men, 3869 did not provide a fasting blood sample at baseline, 1095 had prevalent diabetes and 131 were not given fasting glucose tests at any subsequent study visit. Thus, the present analysis includes 4685 participants. Diabetes was ascertained at baseline and at two study visits between 1968 and 1975 using fasting glucose tests and self-reports of physician-diagnosed diabetes or use of insulin or hypoglycaemic medication. Logistic regression analysis was used to assess the association of coffee intake with risk of incident diabetes while adjusting for covariates (age, BMI, physical activity, smoking, education, alcohol intake, family history of diabetes, intakes of milk and sugar).
Results Five hundred and nineteen participants met the criteria for incident diabetes. Compared with those reporting intake of 1–2 servings of coffee/d, coffee abstainers were at reduced risk (OR = 0·64; 95 % CI 0·43, 0·94). Among coffee drinkers, there was a significant trend of decreasing risk by intake (P = 0·02); intake of ≥4 servings/d was associated with an odds ratio of 0·75 (95 % CI 0·58, 0·97).
Conclusions Study findings support a protective effect of coffee intake on diabetes risk, while also suggesting that abstainers may be at reduced risk.
(Received July 31 2007)
(Accepted May 19 2008)