Article date: November 2001
By: T. Simon, L. Becquemont, B. Hamon, E. Nouyrigat, Y. Chodjania, J. M. Poirier, C. Funck‐Brentano, P. Jaillon, in Volume 52, Issue 5, pages 601-604
Aims To assess the age‐associated changes over time of plasma paraxanthine/caffeine (PAX/CAF) ratios used as a probe for CYP1A2 activity.
Methods Intraindividual and interindividual variabilities in PAX/CAF ratio were compared by phenotyping with caffeine, 16 young and 16 elderly healthy subjects on five occasions.
Results PAX/CAF ratio variability was comparable regardless of age (intraindividual CV: 17.6 ± 6% and 16.2 ± 5.9%, interindividual CV: 48.1 ± 2.9% and 42.7 ± 3.6% in young and elderly, respectively). The PAX/CAF ratio was lower in elderly than in young subjects (95% CI for the difference: 0.004, 0.32) but the difference was not significant in nonsmokers compared separately.
Conclusions The variability over time of the PAX/CAF ratio is not influenced by age.
DOI: 10.1046/j.0306-5251.2001.01494.x
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