Self-reported caffeine consumption miss-matched consumption measured by plasma levels of caffeine and its metabolites: results from two population-based studies

• Published in: European journal of nutrition Vol. 63; no. 5; pp. 1555 - 1564
• Main Authors: Laaboub, Nermine, Ranjbar, Setareh, Strippoli, Marie-Pierre F., Marques-Vidal, Pedro, Estoppey-Younes, Sandrine, Ponte, Belen, Pruijm, Menno, Vogt, Bruno, Ansermot, Nicolas, Crettol, Séverine, Vandenberghe, Frederik, Vollenweider, Peter, Preisig, Martin, Bochud, Murielle, EAP, Chin B.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2024; Springer Nature B.V
• Subjects: Beverages; Caffeine; Chemistry; Chemistry and Materials Science; Coffee; High-performance liquid chromatography; Metabolites; Nutrition; Original Contribution; Plasma; Plasma levels; Population studies; Population-based studies; Self report; spectrometers; Switzerland; Theophylline; ultra-performance liquid chromatography; Switzerland; Paraxanthine; Self-reporting; Plasma levels; Questionnaire; Theophylline; Caffeine
• ISSN: 1436-6207; 1436-6215; 1436-6215
• DOI: 10.1007/s00394-024-03351-9

Importance and objective Self-reported caffeine consumption has been widely used in research while it may be subject to bias. We sought to investigate the associations between self-reported caffeine consumption and plasma levels of caffeine and its two main metabolites (paraxanthine and theophylline) in the community. Methods Data from two population-based studies (SKIPOGH1 and 2 ( N  = 1246) and CoLaus|PsyCoLaus ( N  = 4461)) conducted in Switzerland were used. Self-reported caffeine consumption was assessed using questionnaires. Plasma levels of caffeine and its metabolites were quantified by ultra-high performance liquid chromatography coupled to a tandem quadrupole mass spectrometer. Results In both studies, mean log plasma levels of caffeine and its two metabolites were over 6.48 (plasma levels = 652 ng/ml) when no caffeine consumption was reported. Subsequently, nonlinear associations between log plasma levels and self-reported caffeine consumption were observed in SKIPOGH, with a change of the slope at 3–5 cups of espresso per day in SKIPOGH1 but not SKIPOGH2. In CoLaus|PsyCoLaus, increased daily consumption of caffeinated beverages was associated with increased log plasma levels with a change of the slope at 3 cups. In both studies, declared caffeine consumption higher than 3–5 cups per day was not associated with higher plasma levels of caffeine and its metabolites. Conclusion Self-reports of no or low caffeine consumption and consumption of more than 3–5 cups of coffee should be interpreted with caution, with possible under- or over-estimation. Quantifying plasma levels of caffeine and its metabolites may contribute to a better estimation of caffeine intake.