{"id":"b7512c6e-0040-5ee6-80f4-5b212afb911e","stable_key":"8b3cf083-ea9c-54f5-b42b-bf1fef5b2978:metformin-b12-duration","predicate":"increases","statement":"Years of metformin use were associated with increased risk of B12 deficiency, with an odds ratio of 1.13 per year of use, and combined low and borderline-low B12 was more common in the metformin group at both 5 and 13 years.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"08c1c835-2304-500a-9575-d6afb2d09893","mechanism_event_label":"The risk keeps accumulating the longer the drug is taken.","subject":{"id":"519971b1-5aef-5ad7-8022-840144855cd0","slug":"metformin","display_name":"Metformin","entity_type_key":"drug"},"object":{"id":"365edc29-29f1-5cfa-9a48-78db46d845ae","slug":"metformin-b12-deficiency-risk","display_name":"Risk of biochemical vitamin B12 deficiency during metformin treatment","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"08c1c835-2304-500a-9575-d6afb2d09893","stable_key":"8b3cf083-ea9c-54f5-b42b-bf1fef5b2978:metformin-b12-duration-event","event_type":"observed_intervention","label":"The risk keeps accumulating the longer the drug is taken.","description":"Years of metformin use were associated with increased risk of B12 deficiency, with an odds ratio of 1.13 per year of use, and combined low and borderline-low B12 was more common in the metformin group at both 5 and 13 years.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"519971b1-5aef-5ad7-8022-840144855cd0","slug":"metformin","display_name":"Metformin","entity_type_key":"drug"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"365edc29-29f1-5cfa-9a48-78db46d845ae","slug":"metformin-b12-deficiency-risk","display_name":"Risk of biochemical vitamin B12 deficiency during metformin treatment","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"nutrient_deficiency","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/metformin-research/26900641.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"09cb74c29fe2d647d668d912a9a01962384e38bcc309a29c429d2caaed3048f1\", \"start_char\": 0, \"end_char\": 1842, \"text_sha256\": \"09cb74c29fe2d647d668d912a9a01962384e38bcc309a29c429d2caaed3048f1\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Secondary analysis of the Diabetes Prevention Program Outcomes Study over 13 years","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Metformin 850 mg twice daily versus placebo, then open-label metformin","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Long-duration data. 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Neuropathy and anaemia were measured as prevalence, and the design cannot separate duration from cumulative dose.\nexposure: Metformin 850 mg twice daily versus placebo, then open-label metformin\nevidence_span: {\"source_cache\": \"artifacts/metformin-research/26900641.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"09cb74c29fe2d647d668d912a9a01962384e38bcc309a29c429d2caaed3048f1\", \"start_char\": 0, \"end_char\": 1842, \"text_sha256\": \"09cb74c29fe2d647d668d912a9a01962384e38bcc309a29c429d2caaed3048f1\"}\n[metformin-p26900641] Long-term Metformin Use and Vitamin B12 Deficiency in the Diabetes Prevention Program Outcomes Study. 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