{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T09:02:17Z","timestamp":1784538137474,"version":"3.55.0"},"reference-count":47,"publisher":"Wiley","issue":"6","license":[{"start":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T00:00:00Z","timestamp":1780012800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T00:00:00Z","timestamp":1780012800000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["accp1.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["The Journal of Clinical Pharma"],"published-print":{"date-parts":[[2026,6]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    Obesity\u2010related metabolic and hepatic alterations may influence drug metabolism via cytochrome P450 enzymes. While adult studies suggest altered CYP1A2 activity in obesity, data in pediatric populations remain limited and inconclusive. The objective was to assess the in vivo CYP1A2 phenotype in adolescents aged 11\u201018 years with and without obesity, and to explore sex\u2010based differences in enzyme activity within this age group. In this open\u2010label pharmacokinetic study, which is a part of the CYTONOX study, 65 adolescents aged 11\u201318 years were included, comprising 30 individuals with obesity and 35 without obesity, recruited based on feasibility. The CYP1A2 phenotype was assessed using urinary paraxanthine\/caffeine metabolic ratios following caffeine exposure. Hepatic fat content was measured via magnetic resonance spectroscopy. The study received approval from the Danish Health Authorities (EudraCT: 2014\u2010004554\u201034) and the Regional Ethical Committee of Zealand (SJ\u2010455). Despite metabolic differences and increased hepatic fat in the obese group, the CYP1A2 phenotype did not differ significantly between obese and non\u2010obese adolescents (mean log10 urinary metabolic ratio: 0.82 vs 0.80;\n                    <jats:italic>P<\/jats:italic>\n                    =\u00a0.93). No sex\u2010based differences were observed. Obesity in adolescents does not appear to significantly impact CYP1A2 phenotype assessed by urinary metabolic ratio, in contrast to selected studies in adults. These findings suggest preserved CYP1A2 function during adolescence despite metabolic and hepatic changes. Further longitudinal studies are needed to elucidate the age\u2010related progression of hepatic enzyme activity in context of obesity.\n                  <\/jats:p>","DOI":"10.1002\/jcph.70219","type":"journal-article","created":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T10:24:11Z","timestamp":1780050251000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Hepatic CYP1A2 Activity in Adolescents with and without Obesity Assessed by the Urinary Paraxanthine\u2010to\u2010Caffeine Metabolic Ratio: A Pharmacokinetic Study"],"prefix":"10.1002","volume":"66","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0007-6158","authenticated-orcid":false,"given":"Christina","family":"Gade","sequence":"first","affiliation":[{"name":"Department of Clinical Pharmacology Copenhagen University Hospital, Bispebjerg and Frederiksberg  Copenhagen Denmark"},{"name":"Department of Clinical Medicine Copenhagen University  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Clinical Medicine Copenhagen University  Copenhagen Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Troels","family":"Riis","sequence":"additional","affiliation":[{"name":"Department of Clinical Pharmacology Copenhagen University Hospital, Bispebjerg and Frederiksberg  Copenhagen Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jens Christian","family":"Holm","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine Copenhagen University  Copenhagen Denmark"},{"name":"Children's Obesity Clinic, European Association for the Study of Obesity (EASO), Department of Pediatrics Zealand University Hospital  Holbaek Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ulrik","family":"Lausten\u2010Thomsen","sequence":"additional","affiliation":[{"name":"Department of Neonatal and Paediatric Intensive Care Copenhagen University Hospital, Rigshospitalet  Copenhagen 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