{"doi":"10.3233/jad-201096","title":"Plasma Vitamin B12 Levels, High-Dose Vitamin B12 Treatment, and Risk of Dementia","abstract":"BACKGROUND: It is controversial whether B12 deficiency causes dementia or B12 treatment can prevent dementia. OBJECTIVE: To assess associations between low plasma (P-)B12 levels, B12 treatment, and risk of Alzheimer's disease (AD; primary outcome) and all-cause or vascular dementia (secondary outcomes). METHODS: We conducted a population-based cohort study using Danish registry data to assess associations between low P-B12 levels, high-dose injection or oral B12 treatment, and risk of dementia (study period 2000-2013). The primary P-B12 cohort included patients with a first-time P-B12 measurement whose subsequent B12 treatment was recorded. The secondary B12 treatment cohort included patients with a first-time B12 prescription and P-B12 measurement within one year before this prescription. For both cohorts, patients with low P-B12 levels (<200 pmol/L) were propensity score-matched 1:1 with patients with normal levels (200-600 pmol/L). We used multivariable Cox regression to compute 0-15-year hazard ratios for dementia. RESULTS: For low P-B12 and normal P-B12 level groups, we included 53,089 patients in the primary P-B12 cohort and 13,656 patients in the secondary B12 treatment cohort. In the P-B12 cohort, hazard ratios for AD centered around one, regardless of follow-up period or treatment during follow-up. In the B12 treatment cohort, risk of AD was unaffected by low pre-treatment P-B12 levels, follow-up period and type of B12 treatment. Findings were similar for all-cause and vascular dementia. CONCLUSION: We found no associatio1n between low P-B12 levels and dementia. Associations were unaffected by B12 treatment. Results do not support routine screening for B12 deficiency in patients with suspected dementia.","journal":"Journal of Alzheimer s Disease","year":2021,"id":180923,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":16,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9589,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":355538,"name":"Erzsébet Horváth–Puhó","orcid":"0000-0002-3594-2212","position":1,"is_corresponding":false},{"id":236234,"name":"Henrik Toft Sørensen","orcid":"0000-0003-4299-7040","position":2,"is_corresponding":false},{"id":471789,"name":"Ebba Nexø","orcid":"0000-0001-9406-9081","position":3,"is_corresponding":false},{"id":731075,"name":"Lars Pedersen","orcid":"0000-0002-9341-3888","position":4,"is_corresponding":false},{"id":355537,"name":"Anne Gulbech Ording","orcid":"0000-0002-8073-7664","position":5,"is_corresponding":false},{"id":355540,"name":"Victor W. Henderson","orcid":"0000-0003-1198-9240","position":6,"is_corresponding":false},{"id":731074,"name":"Johan Frederik Håkonsen Arendt","orcid":"0000-0003-4423-4813","position":0,"is_corresponding":true}],"reference_count":35,"raw_metadata":null,"created_at":"2026-07-18T23:48:01.257885Z","pmid":"33459639","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}