{"doi":"10.1210/clinem/dgab742","title":"Vitamin D Supplementation and Fractures in Adults: A Systematic Umbrella Review of Meta-Analyses of Controlled Trials","abstract":"CONTEXT: The growing number of systematic reviews/meta-analyses (SR/MAs) on vitamin D (± calcium) for fracture prevention has led to contradictory guidelines. OBJECTIVE: This umbrella review aims to assess the quality and explore the reasons for the discrepancy of SR/MAs of trials on vitamin D supplementation for fracture risk reduction in adults. METHODS: We searched 4 databases (2010-2020), Epistemonikos, and references of included SRs/MAs, and we contacted experts in the field. We used A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR-2) for quality assessment. We compared results and investigated reasons for discordance using matrices and subgroup analyses (PROSPERO registration: CRD42019129540). We included 13 SR/MAs on vitamin D and calcium (Ca/D) and 19 SR/MAs on vitamin D alone, compared to placebo/control. RESULTS: Only 2 from 10 SRs/MAs on Ca/D were of moderate quality. Ca/D reduced the risk of hip fractures in 8 of 12 SRs/MAs (relative risk [RR] 0.61-0.84), and any fractures in 7 of 11 SR/MAs (RR 0.74-0.95). No fracture risk reduction was noted in SRs/MAs exclusively evaluating community-dwelling individuals or in those on vitamin D alone compared to placebo/control. Discordance in results between SRs/MAs stems from inclusion of different trials, related to search periods and eligibility criteria, and varying methodology (using intention to treat, per-protocol, or complete case analysis from individual trials). CONCLUSION: Ca/D reduces the risk of hip and any fractures, possibly driven by findings from institutionalized individuals. Individual participant data meta-analyses of patients on Ca/D with sufficient follow-up periods, and subgroup analyses, would unravel determinants for a beneficial response to supplementation.","journal":"The Journal of Clinical Endocrinology & Metabolism","year":2021,"id":151815,"datarank":2.3238879650723447,"base_score":4.418840607796598,"endowment":4.418840607796598,"self_citation_contribution":0.6628260911694899,"citation_network_contribution":1.6610618739028546,"self_endowment_contribution":0.6628260911694899,"citer_contribution":1.6610618739028546,"corpus_percentile":null,"corpus_rank":null,"citation_count":82,"citer_count":67,"citers_with_citation_signal":50,"citers_with_endowment":50,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.5836,"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":644990,"name":"Dania S. Bacha","orcid":"0000-0003-1120-9021","position":1,"is_corresponding":false},{"id":644991,"name":"Charbel Gharios","orcid":"0000-0003-2262-4714","position":2,"is_corresponding":false},{"id":482537,"name":"Sara Ajjour","orcid":"0000-0003-1812-7387","position":3,"is_corresponding":false},{"id":644992,"name":"Mariam Assaad","orcid":"0000-0001-6763-046X","position":4,"is_corresponding":false},{"id":644993,"name":"Yara Jabbour","orcid":"0000-0003-1101-1795","position":5,"is_corresponding":false},{"id":644994,"name":"Francesca Kahale","orcid":"0000-0001-6476-0066","position":6,"is_corresponding":false},{"id":518107,"name":"Aya Bassatne","orcid":"0000-0002-7841-3986","position":7,"is_corresponding":false},{"id":644995,"name":"S. Antoun","orcid":"0000-0002-2911-1607","position":8,"is_corresponding":false},{"id":16499,"name":"Elie A. Akl","orcid":"0000-0002-3444-8618","position":9,"is_corresponding":false},{"id":217248,"name":"Roger Bouillon","orcid":"0000-0002-6446-3763","position":10,"is_corresponding":false},{"id":16410,"name":"Paul Lips","orcid":"0000-0002-2627-8145","position":11,"is_corresponding":false},{"id":644996,"name":"Peter R. Ebeling","orcid":"0000-0002-2921-3742","position":12,"is_corresponding":false},{"id":397361,"name":"Ghada El‐Hajj Fuleihan","orcid":"0000-0002-2076-5858","position":13,"is_corresponding":false},{"id":482535,"name":"Marlene Chakhtoura","orcid":"0000-0003-0012-986X","position":0,"is_corresponding":true}],"reference_count":90,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-18T23:43:16.823357Z","pmid":"34687206","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":[]}