Objectives: To study the joint association of coffee consumption and serum -glutamyltransferase (GGT) levels on the risk of developing type 2 diabetes.
Design, setting and subjects: A total of 21 826 Finnish men and women who were 35–74 years of age and without any history of diabetes at baseline (years 1982, 1987, 1992 and 1997) were included in the present analyses. They were prospectively followed up for onset of type 2 diabetes (n=862 cases), death or until the end of the year 2002. Coffee consumption, serum GGT and other study parameters were determined at baseline using standardized measurements. Analyses were stratified by the serum GGT level classified into two classes using the 75th sex-specific percentiles as the cut point.
Results: Coffee consumption was significantly and inversely associated with incident diabetes among both men and women. Serum GGT modified the association between coffee consumption and incident diabetes. Subjects in the high category of coffee consumption with the GGT level 75th percentile showed a significant inverse association for women, and for both sexes combined. The association was not significant in subjects with the GGT level 75th percentile. There was a significant interaction effect of GGT and coffee consumption on risk of type II diabetes in data of women (P=0.05) and in both sexes combined (P=0.02).
Conclusions: Habitual coffee consumption is associated with lower incidence of type 2 iabetes particularly in those with higher baseline serum GGT levels.
Objective: To examine joint associations of coffee consumption and other factors (including physical activity, obesity and alcohol consumption) with the risk of type 2 diabetes.
Design: Prospective follow-up study.
Subjects: In all, 10 188 Finnish men and 11 197 women aged 35–74 years without a history of stroke, coronary heart disease or diabetes at baseline.
Measurement: A self-administered questionnaire data on coffee, tea, alcohol and other food consumption, physical activity, smoking, socio-economic factors and medical history, together with measured height, weight and blood pressure using standardized protocol.
Results: During a mean follow-up of 13.4 years, there were 964 incident cases of type 2 diabetes. Multivariate-adjusted (age, study year, systolic blood pressure, education, smoking, physical activity, body mass index (BMI) and fruit, vegetable, sausage, bread, alcohol and tea consumption) hazard ratio of type 2 diabetes in participants who drank 0–2, 3–6 and 7 cups of coffee were 1.00, 0.77 and 0.66 (P=0.022 for trend) in men, 1.00, 0.71 and 0.52 (P=0.001 for trend) in women, and 1.00, 0.75 and 0.61 (P<0.001>Conclusions: Coffee drinking was associated with a reduced risk of type 2 diabetes in both men and women, and this association was observed regardless of the levels of physical activity, BMI and alcohol consumption
(1) European Journal of Clinical Nutrition (2008) 62, 178–185
(2) International Journal of Obesity (2006) 30, 1742–1749