{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T04:45:54Z","timestamp":1785818754654,"version":"3.56.0"},"reference-count":34,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2026,8,1]],"date-time":"2026-08-01T00:00:00Z","timestamp":1785542400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100008130","name":"Pusan National University Hospital","doi-asserted-by":"crossref","award":["20250049"],"award-info":[{"award-number":["20250049"]}],"id":[{"id":"10.13039\/501100008130","id-type":"DOI","asserted-by":"crossref"}]},{"award":["20250049"],"award-info":[{"award-number":["20250049"]}],"id":[{"id":"https:\/\/ror.org\/027zf7h57","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Background\/Objectives: To examine the association between caffeine intake and mental health- and sleep-related outcomes, including anxiety, sleep duration, and perceived stress, in a nationally representative sample of Korean adults. Methods: We analyzed 20,504 participants from the Korea National Health and Nutrition Examination Survey (KNHANES) 2021\u20132024. Caffeine intake was categorized into six groups, and mental health- and sleep-related outcomes included clinically significant anxiety symptoms (GAD-7 \u2265 10), sleep duration, and perceived stress. Survey-weighted multivariable logistic regression models and restricted cubic spline analyses were used to evaluate associations between caffeine intake and mental health- and sleep-related outcomes, adjusting for demographic, socioeconomic, behavioral, dietary, and clinical factors. Results: The prevalence of clinically significant anxiety symptoms was 4.7%. Restricted cubic spline analyses demonstrated a non-linear association between caffeine intake and anxiety (p-overall = 0.010; p-nonlinear = 0.016). Higher caffeine intake was associated with progressively increasing odds of short sleep duration (&lt;6 h\/day), indicating a clear dose\u2013response relationship (p-overall &lt; 0.001; p-nonlinear &lt; 0.001). Higher caffeine intake was also associated with increased perceived stress (p-overall = 0.025), although evidence for a nonlinear relationship was weaker (p-nonlinear = 0.062). These findings were generally consistent across multivariable-adjusted models. Conclusions: Caffeine intake is differentially associated with mental health- and sleep-related outcomes, with excessive intake related to adverse effects on sleep and stress.<\/jats:p>","DOI":"10.3390\/nu18152488","type":"journal-article","created":{"date-parts":[[2026,8,3]],"date-time":"2026-08-03T06:17:40Z","timestamp":1785737860000},"page":"2488","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Beverage-Derived Caffeine Intake, Sleep Duration, and Mental Health Among Korean Adults: A Cross-Sectional Analysis of KNHANES 2021\u20132024"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6715-0447","authenticated-orcid":false,"given":"Jinmi","family":"Kim","sequence":"first","affiliation":[{"name":"Department of Biostatistics, Clinical Trial Center, Biomedical Research Institute, Pusan National University Hospital, Busan 49241, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1786-2737","authenticated-orcid":false,"given":"Yu Hyeon","family":"Yi","sequence":"additional","affiliation":[{"name":"Department of Family Medicine and Medical Research Institute, Pusan National University Hospital, Busan 49241, Republic of Korea"},{"name":"Department of Family Medicine, Pusan National University School of Medicine, Yangsan 50612, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,1]]},"reference":[{"key":"ref_1","first-page":"e86215","article-title":"Caffeine Consumption Patterns, Health Impacts, and Media Influence: A Narrative Review","volume":"17","author":"Rauf","year":"2025","journal-title":"Cureus"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1016\/j.smrv.2016.01.006","article-title":"Coffee, Caffeine, and Sleep: A Systematic Review of Epidemiological Studies and Randomized Controlled Trials","volume":"31","author":"Clark","year":"2017","journal-title":"Sleep Med. 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