{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T05:54:37Z","timestamp":1790747677829,"version":"4.1.0"},"reference-count":23,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:00:00Z","timestamp":1790726400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Med."],"abstract":"<jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>To characterize serum 25-hydroxyvitamin D [25(OH)D] trajectories during peginterferon alfa-2b (Peg-IFN) add-on to ongoing tenofovir alafenamide (TAF) therapy in chronic hepatitis B and explore associations with hepatitis B surface antigen (HBsAg).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This retrospective cohort identified 203 consecutive patients, of whom 190 contributed longitudinal data through week 48. The primary random-intercept mixed-effects model used categorical visit time and adjusted for seasonality, age, and sex. Continuous-time, random-slope, visit-timing, and HBsAg-censoring analyses assessed sensitivity.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      The primary adjusted week-48 25(OH)D difference was \u22127.9\u2005nmol\/L (95% CI, \u22129.8 to \u22126.0) (\n                      <jats:italic>P<\/jats:italic>\n                      \u2009&amp;lt;\u20090.001); the secondary continuous-time estimate was \u22128.3\u2005nmol\/L over 48 weeks. Observed concentrations declined through week 36 and partially rebounded at week 48. The proportion below 47.7\u2005nmol\/L increased from 21.1% to 34.7%. The adjusted total serum calcium trend was \u22120.061\u2005mmol\/L (95% CI, \u22120.074 to \u22120.049). Triglycerides increased while cholesterol fractions decreased. At week 48, 104\/190 patients (54.7%) had an HBsAg decline of at least 1 log10 and 50\/190 (26.3%) had visit-specific HBsAg loss. The concurrent 48-week change correlation was weak (\n                      <jats:italic>\u03c1<\/jats:italic>\n                      \u2009=\u20090.150; FDR-adjusted\n                      <jats:italic>P<\/jats:italic>\n                      \u2009=\u20090.117), and the magnitude of 25(OH)D decline was not independently associated with either binary endpoint. Within patients, each 10\u2005nmol\/L increase in 25(OH)D was associated with a 0.068-log10\u2005IU\/mL increase in concurrent HBsAg (95% CI, 0.020 to 0.116;\n                      <jats:italic>P<\/jats:italic>\n                      \u2009=\u20090.006).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Serum 25(OH)D showed a non-linear decline during 48 weeks of follow-up, and the week-48 difference remained evident after adjustment for seasonality. However, without a concurrent comparator, the observed change cannot be attributed specifically to Peg-IFN, TAF, or their combination. Exploratory analyses suggested only a weak concurrent relationship between 25(OH)D and HBsAg, without evidence of prediction or causality. The clinical relevance of the observed changes in 25(OH)D and total serum calcium warrants further prospective investigation.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fmed.2026.1976727","type":"journal-article","created":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T04:56:05Z","timestamp":1790744165000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Season-adjusted longitudinal changes in serum 25-hydroxyvitamin D during pegylated interferon add-on to ongoing tenofovir alafenamide therapy in chronic hepatitis B: a real-world cohort study"],"prefix":"10.3389","volume":"13","author":[{"given":"Ning","family":"Han","sequence":"first","affiliation":[{"name":"Center of Infectious Diseases, West China Hospital of Sichuan University","place":["Chengdu, China"]},{"name":"Laboratory of Infectious and Liver Disease, Institute of Infectious Diseases, West China Hospital, Sichuan 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