Association of coffee consumption and CYP1A2 polymorphism with risk of impaired fasting glucose in hypertensive patients
Whether and how coffee use influences glucose metabolism is still a matter for debate. We investigated whether baseline coffee consumption is longitudinally associated with risk of impaired fasting glucose in a cohort of 18-to-45 year old subjects screened for stage 1 hypertension and whether CYP1A2 polymorphism modulates this association. A total of 1,180 nondiabetic patients attending 17 hospital centers were included. Seventy-four percent of our subjects drank coffee. Among the coffee drinkers, 87 % drank 1–3 cups/day (moderate drinkers), and 13 % drank over 3 cups/day (heavy drinkers). Genotyping of CYP1A2 SNP was performed by real time PCR in 639 subjects. At the end of a median follow-up of 6.1 years, impaired fasting glucose was found in 24.0 % of the subjects. In a multivariable Cox regression coffee use was a predictor of impaired fasting glucose at study end, with a hazard ratio (HR) of 1.3 (95 % CI 0.97–1.8) in moderate coffee drinkers and of 2.3 (1.5–3.5) in heavy drinkers compared to abstainers. Among the subjects stratified by CYP1A2 genotype, heavy coffee drinkers carriers of the slow *1F allele (59 %) had a higher adjusted risk of impaired fasting glucose (HR 2.8, 95 % CI 1.3–5.9) compared to abstainers whereas this association was of borderline statistical significance among the homozygous for the A allele (HR 1.7, 95 % CI 0.8–3.8). These data show that coffee consumption increases the risk of impaired fasting glucose in hypertension particularly among carriers of the slow CYP1A2 *1F allele.
KeywordsCoffee Caffeine Hypertension Prediabetes CYP1A2 Genes
The study was funded by the University of Padova, Padova, Italy, and by the Associazione “18 Maggio 1370”, San Daniele del Friuli, Italy.
Conflict of interest
The authors have no financial interest in the subject matter or materials discussed in the manuscript.
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