Associations of 25-hydroxyvitamin D with markers of inflammation, insulin resistance and obesity in black and white community-dwelling adults.
OBJECTIVE
Vitamin D is a fat-soluble vitamin classically known for its role in calcium absorption and bone health. Growing evidence indicates that vitamin D deficiency may be associated with inflammation, insulin resistance, and obesity. However, prior studies examining the association of vitamin D with metabolic risk factors had relatively low representation of individuals of black race, limiting their ability to characterize associations of vitamin D and parameters of metabolic health in black vs. white individuals.


METHODS
We examined associations of 25-hydroxyvitamin D (25(OH)D) concentrations with markers of inflammation (interleukin [IL]-6, IL-10, high sensitivity C-reactive protein [hsCRP]), insulin sensitivity (adiponectin, resistin, HOMA-IR), and obesity (body mass index [BMI], waist circumference) in 1,042 participants from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a large national cohort of black and white adults 45 years or older.


RESULTS
In unadjusted analyses, lower 25(OH)D concentrations were associated with higher IL-6 and hsCRP concentrations; lower adiponectin concentrations; higher HOMA-IR; and higher BMI and waist circumference (P<0.05 for all). After adjustment for sociodemographic, clinical, lifestyle, and laboratory variables, lower 25(OH) D concentrations remained associated with lower adiponectin concentrations, higher IL-6 concentrations, higher HOMA-IR, and higher BMI and waist circumference (P<0.05 for all). The magnitude of these associations did not differ by race (Pinteraction>0.1).


CONCLUSIONS
Lower 25(OH)D concentrations are associated with disturbances in metabolic health in both blacks and whites. Whether correcting vitamin D deficiency could offer a beneficial therapy for additional disease prevention requires further study.
Department of Medicine, University of Alabama at Birmingham, Birmingham, AL.
Jennifer L
JL
Jackson
Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL.
Suzanne E
SE
Judd
Department of Medicine, University of Alabama at Birmingham, Birmingham, AL.
Bhupesh
B
Panwar
Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL.
Virginia J
VJ
Howard
Department of Medicine, University of Alabama at Birmingham, Birmingham, AL.
Virginia G
VG
Wadley
Department of Pathology, University of Vermont College of Medicine, Burlington, VT.
Nancy S
NS
Jenny
Department of Medicine, University of Alabama at Birmingham, Birmingham, AL; Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL.
Orlando M
OM
Gutiérrez
inflammation; insulin resistance; metabolic syndrome; obesity; vitamin D