title: Diabetes is the main factor accounting for hypomagnesemia in obese subjects.
abstract: OBJECTIVE
  Type 2 diabetes (T2DM) and obesity are associated with magnesium deficiency. We aimed to determine whether the presence of type 2 diabetes and the degree of metabolic control are related to low serum magnesium levels in obese individuals.
  
  
  METHODS
  A) Case-control study: 200 obese subjects [50 with T2DM (cases) and 150 without diabetes (controls)] prospectively recruited. B) Interventional study: the effect of bariatric surgery on serum magnesium levels was examined in a subset of 120 obese subjects (40 with type 2 diabetes and 80 without diabetes).
  
  
  RESULTS
  Type 2 diabetic patients showed lower serum magnesium levels [0.75±0.07 vs. 0.81±0.06 mmol/L; mean difference -0.06 (95% CI -0.09 to -0.04); p<0.001] than non-diabetic patients. Forty-eight percent of diabetic subjects, but only 15% of non-diabetic subjects showed a serum magnesium concentration lower than 0.75 mmol/L. Significant negative correlations between magnesium and fasting plasma glucose, HbA1c, HOMA-IR, and BMI were detected. Multiple linear regression analysis showed that fasting plasma glucose and HbA1c independently predicted serum magnesium. After bariatric surgery serum magnesium increased only in those patients in whom diabetes was resolved, but remain unchanged in those who not, without difference in loss weight between groups. Changes in serum magnesium negatively correlated with changes in fasting plasma glucose and HbA1c. Absolute changes in HbA1c independently predicted magnesium changes in the multiple linear regression analysis.
  
  
  CONCLUSIONS
  Our results provide evidence that the presence of diabetes and the degree of metabolic control are essential in accounting for the lower levels of magnesium that exist in obese subjects.
authors.affiliation: CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Diabetes and Metabolism Research Unit, Endocrinology Department, Universitat Autònoma de Barcelona, Barcelona, Spain. alecube@vhebron.net
authors.forename: Albert
authors.initials: A
authors.lastname: Lecube
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Baena-Fustegueras
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Fort
authors.forename: Dolors
authors.initials: D
authors.lastname: Pelegrí
authors.forename: Cristina
authors.initials: C
authors.lastname: Hernández
authors.forename: Rafael
authors.initials: R
authors.lastname: Simó
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000706:statistics & numerical data; D016022:Case-Control Studies; D018849:Controlled Clinical Trials as Topic; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications* / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008274:Magnesium / Q000097:blood; D008275:Magnesium Deficiency / Q000097:blood / Q000453:epidemiology* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000150:complications* / Q000453:epidemiology* / Q000601:surgery; D012307:Risk Factors; D015431:Weight Loss / Q000502:physiology
chemical_list: D008274:Magnesium