{"id":"cb75008d-9e2d-507f-b4bc-111f6ead19c6","stable_key":"1deb434a-3547-51a0-a038-87b1ce79ec38:vd-hammami-d3-decreases-d2","predicate":"lowers","statement":"At day 28, D3 produced a 9.8 nmol/L greater decline in 25(OH)D2 than placebo (95% CI5.2–14.4); by day 56 the 1.7 nmol/L difference was not significant (CI−7.6–11.1).","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"a56df72d-35e1-56e1-9c1d-13e88896c0d2","mechanism_event_label":"The reverse effect also occurred after D3, and its between-group difference was shorter-lived.","subject":{"id":"b162e431-b442-5400-9335-ec91f7875a4e","slug":"cholecalciferol","display_name":"Cholecalciferol","entity_type_key":"small_molecule"},"object":{"id":"9dd681dd-a29c-5684-9610-e695742ff534","slug":"serum-25-hydroxyvitamin-d2","display_name":"Serum 25-hydroxyvitamin D2 concentration","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"a56df72d-35e1-56e1-9c1d-13e88896c0d2","stable_key":"1deb434a-3547-51a0-a038-87b1ce79ec38:vd-hammami-d3-decreases-d2-event","event_type":"observed_intervention","label":"The reverse effect also occurred after D3, and its between-group difference was shorter-lived.","description":"At day 28, D3 produced a 9.8 nmol/L greater decline in 25(OH)D2 than placebo (95% CI5.2–14.4); by day 56 the 1.7 nmol/L difference was not significant (CI−7.6–11.1).","status":"provisional","compartment":null,"participants":[{"entity":{"id":"6e1cf31c-f78e-596b-b1b3-70585cf9c948","slug":"ergocalciferol","display_name":"Ergocalciferol / vitamin D2","entity_type_key":"small_molecule"},"role":"preload","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"b162e431-b442-5400-9335-ec91f7875a4e","slug":"cholecalciferol","display_name":"Cholecalciferol","entity_type_key":"small_molecule"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"9dd681dd-a29c-5684-9610-e695742ff534","slug":"serum-25-hydroxyvitamin-d2","display_name":"Serum 25-hydroxyvitamin D2 concentration","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"false","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Two randomized single-dose experiments; 100 volunteers, 97 analyzed","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Study 2: D2 50, 000 IU preload; four days later D3 50, 000 IU or placebo.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"No direct enzyme-flux assay. Reciprocal fraction changes are not proof that D2 is toxic or that net total vitamin D falls.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-d","display_name":"Vitamin D2 and D3","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The reverse effect also occurred after D3, and its between-group difference was shorter-lived.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[hammami2019] Vitamin-D2 treatment-associated decrease in 25(OH)D3 level is a reciprocal phenomenon: a randomized controlled trial. (2019). https://pubmed.ncbi.nlm.nih.gov/30658603/ DOI: 10.1186/s12902-019-0337-8","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Human circulating measurements","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"60e6333f-6001-5f6f-8a29-30c5442bc04e","evidence_kind":"source_excerpt","locator":"Lines 1418-1429","start_line":1418,"end_line":1429,"excerpt":"### vd-hammami-d3-decreases-d2\nAt day 28, D3 produced a 9.8 nmol/L greater decline in 25(OH)D2 than placebo (95% CI5.2–14.4); by day 56 the 1.7 nmol/L difference was not significant (CI−7.6–11.1).\nCondition category: normal\nnutrient_topic: Vitamin D2 and D3 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The reverse effect also occurred after D3, and its between-group difference was shorter-lived.\norganism: Homo sapiens\ntissue_or_cell_type: Human circulating measurements\nexperimental_model: Two randomized single-dose experiments; 100 volunteers, 97 analyzed\nlimitations: No direct enzyme-flux assay. Reciprocal fraction changes are not proof that D2 is toxic or that net total vitamin D falls.\nexposure: Study 2: D2 50, 000 IU preload; four days later D3 50, 000 IU or placebo.\ncross_nutrient: false\n[hammami2019] Vitamin-D2 treatment-associated decrease in 25(OH)D3 level is a reciprocal phenomenon: a randomized controlled trial. (2019). https://pubmed.ncbi.nlm.nih.gov/30658603/ DOI: 10.1186/s12902-019-0337-8","model_system":"Two randomized single-dose experiments; 100 volunteers, 97 analyzed","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [hammami2019] Vitamin-D2 treatment-associated decrease in 25(OH)D3 level is a reciprocal phenomenon: a randomized controlled trial. (2019). https://pubmed.ncbi.nlm.nih.gov/30658603/ DOI: 10.1186/s12902-019-0337-8","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"c95c763c-5b31-5b3f-a2f8-2dfe5ef0d3ca","stable_key":"import-1deb434a-3547-51a0-a038-87b1ce79ec38","title":"Vitamin D2 and D3: mechanisms, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"51004bf0d78db6146b8f198b0688a3cc7d4ea9822415a9c034f4c8790fb4e38b","revision_id":"d52ff207-a311-5f24-96f4-462838792db5","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}