title: Database evaluation of the association between serum magnesium levels and the risk of atrial fibrillation in the community.
abstract: BACKGROUND
  In population studies, mild hypomagnesemia, determined by a single measurement, was associated with incident atrial fibrillation, over ~20 years of follow-up. We sought to determine whether mild (≤ 1.7 mg/dL) and moderate (≤ 1.5mg/dL) hypomagnesemia are temporally associated with increased incidence of atrial fibrillation (AF) in the community.
  
  
  METHODS
  Health Maintenance Organization (HMO) database cohort study including beneficiaries with ≥ 1 serum magnesium measurement between 2004 and 2013. The follow-up period was defined from the first magnesium measurement to first listing in an AF registry (for cases) and December 2013 or date of death or loss to follow-up (for controls). We analyzed the association between serum magnesium quintiles, as well as the above clinically relevant hypomagnesemia thresholds, and incident AF using Cox proportional hazard regression analysis, adjusting for confounders. The association between serum magnesium and AF occurring within 3 months was also examined.
  
  
  RESULTS
  Among 162,162 subjects, 2228 (1.4%) developed AF over a median follow-up of 25.3 months. Compared to the middle quintile the lowest magnesium quintile (≤ 1.9 mg/dL) had a significantly higher risk of AF (HR, 1.21; 95% CI: 1.07-1.37). Increased AF risk was also associated with mild (HR, 1.44; 95% CI: 1.20-1.73) and moderate hypomagnesemia (HR, 1.57; 95% CI: 1.14-2.15). No association was found when limiting the follow-up period to 3 months.
  
  
  CONCLUSIONS
  In our study, hypomagnesemia was associated with incident AF over prolonged but not short-term follow-up periods, suggesting that this association may not be causal.
authors.affiliation: Institute of Clinical Pharmacology, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Noa
authors.initials: N
authors.lastname: Markovits
authors.affiliation: Division of Clinical Pharmacology and Toxicology, Rambam Health Care Campus, Haifa, Israel; Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kurnik
authors.affiliation: Department of Pharmacy and Clinical Pharmacology, Maccabi Healthcare Services, Israel; Institute of Clinical Pharmacology, Sheba Medical Center, Tel Hashomer, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Hillel
authors.initials: H
authors.lastname: Halkin
authors.affiliation: Institute of Clinical Pharmacology, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Reuma
authors.initials: R
authors.lastname: Margalit
authors.affiliation: Department of Pharmacy and Clinical Pharmacology, Maccabi Healthcare Services, Israel.
authors.forename: Martin
authors.initials: M
authors.lastname: Bialik
authors.affiliation: Department of Pharmacy and Clinical Pharmacology, Maccabi Healthcare Services, Israel.
authors.forename: Yossi
authors.initials: Y
authors.lastname: Lomnicky
authors.affiliation: Department of Pharmacy and Clinical Pharmacology, Maccabi Healthcare Services, Israel; Institute of Clinical Pharmacology, Sheba Medical Center, Tel Hashomer, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel. Electronic address: ronen.loebstein@sheba.health.gov.il.
authors.forename: Ronen
authors.initials: R
authors.lastname: Loebstein
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D016208:Databases, Factual / Q000592:standards*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008274:Magnesium / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012111:Residence Characteristics; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D008274:Magnesium
keywords: Atrial fibrillation; Database cohort study; Hypomagnesemia