title: Standardized serum 25-hydroxyvitamin D concentrations are inversely associated with cardiometabolic disease in U.S. adults: a cross-sectional analysis of NHANES, 2001-2010.
abstract: Previously reported associations between vitamin D status, as measured by serum 25-hydroxyvitamin D [25(OH)D] concentrations, and cardiometabolic risk factors were largely limited by variability in 25(OH)D assay performance. In accordance with the Vitamin D Standardization Program, serum 25(OH)D measurement was recently standardized in the National Health and Nutrition Examination Survey (NHANES) to reduce laboratory and method related differences in serum 25(OH)D results. We evaluated the overall and ethnic-specific associations between the newly standardized serum 25(OH)D concentrations and cardiometabolic risk in U.S. adults.
  
  
  
  This study examined standardized 25(OH)D data from five cycles of the NHANES (2001-2010). The total sample included 7674 participants (1794 Mexican-Americans, 4289 non-Hispanic whites, and 1591 non-Hispanic blacks) aged ≥ 20 years who were examined in the morning after overnight fasting. Serum 25(OH)D was directly measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 2007-2010, and was predicted from LC-MS/MS equivalents for 2001-2006. Serum 25(OH)D levels were categorized into quartiles (<43.4, 43.4-58.6, 58.7-74.2, ≥74.3 nmol/L). Cardiometabolic risk was defined by the homeostatic model assessment of insulin resistance (HOMA-IR), metabolic syndrome (MetS), and Framingham cardiovascular disease (CVD) risk. Prevalence ratios and 95% confidence intervals were calculated using modified Poisson regression.
  
  
  
  After full adjustment for confounders, serum 25(OH)D ≥74.3 nmol/L was associated with lower cardiometabolic risk compared to 25(OH)D <43.4 nmol/L in the overall sample [HOMA-IR: 0.70 (0.59, 0.84); MetS: 0.82 (0.74, 0.91); CVD risk: 0.78 (0.66, 0.91)]. These associations remained significant in Mexican-Americans [HOMA-IR: 0.54 (0.35, 0.82); MetS: 0.73 (0.55, 0.96)], non-Hispanic whites [HOMA-IR: 0.81 (0.68, 0.96); MetS: 0.84 (0.73, 0.95); CVD risk: 0.78 (0.64, 0.93)]; and in non-Hispanic blacks [HOMA-IR: 0.67 (0.45, 0.99); MetS: 0.75 (0.56, 0.97); CVD risk: 0.58 (0.41, 0.81)].
  
  
  
  Low vitamin D status is a significant risk factor for cardiometabolic disease in U.S. adults based on standardized serum 25(OH)D results, irrespective of ethnic background. Future studies using standardized 25(OH)D data are needed to confirm these results, particularly amongst U.S. blacks with 25(OH)D concentrations above 75 nmol/L.
authors.affiliation: School of Kinesiology and Health Science, York University, Toronto, M3J1P3, ON, Canada. khalidib@yorku.ca.
authors.forename: Banaz
authors.identifier: 0000-0001-7336-2350
authors.initials: B
authors.lastname: Al-Khalidi
authors.affiliation: Pure North S'Energy Foundation, Calgary, AB, Canada.
authors.forename: Samantha M
authors.initials: SM
authors.lastname: Kimball
authors.affiliation: School of Kinesiology and Health Science, York University, Toronto, M3J1P3, ON, Canada.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Rotondi
authors.affiliation: School of Kinesiology and Health Science, York University, Toronto, M3J1P3, ON, Canada.
authors.forename: Chris I
authors.initials: CI
authors.lastname: Ardern
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000097:blood* / Q000453:epidemiology; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000453:epidemiology; D008875:Middle Aged; D009749:Nutrition Surveys; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires; D053719:Tandem Mass Spectrometry; D014280:Triglycerides / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications*; D055105:Waist Circumference; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D014280:Triglycerides; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Ethnicity; Framingham CVD risk; Insulin resistance; Metabolic syndrome population survey; Standardized 25-Hydroxyvitamin D; Vitamin D