@article {6062, title = {Circulating 25-hydroxyvitamin D is associated with insulin resistance cross-sectionally but not longitudinally in older adults: The Cardiovascular Health Study.}, journal = {Metabolism}, volume = {62}, year = {2013}, month = {2013 Dec}, pages = {1788-94}, abstract = {

BACKGROUND: Despite extensive study, the role of vitamin D in insulin resistance and secretion remains unclear.

OBJECTIVE: To examine the cross-sectional and longitudinal relationships between 25-hydroxyvitamin D (25(OH)D) concentrations and indices of insulin resistance and secretion in older adults.

METHODS AND RESULTS: Among 2134 participants of the Cardiovascular Health Study who were free from cardiovascular disease, we measured serum 25(OH)D concentrations in samples collected in 1992-1993. We examined insulin resistance and secretion using Homeostasis Model Assessment (HOMA) estimates cross-sectionally and among 1469 participants who had repeated HOMA measures four years later (1996-1997). In cross-sectional analysis, each 10 ng/mL increment in 25(OH)D concentration was associated with a 0.09 lower adjusted HOMA-IR [95\% CI (-0.17, -0.02), p=0.01]. However, baseline 25(OH)D concentrations were not associated with change in HOMA-IR over 4 years of follow up (p=0.48). 25(OH)D concentrations were not associated with insulin secretion, as determined by HOMA-β, in either cross-sectional or longitudinal analysis.

CONCLUSIONS: Circulating 25(OH)D concentrations are associated with lower insulin resistance in cross-sectional but not longitudinal analyses. Whether this reflects residual confounding in cross-sectional analyses or the short-term nature of the relationship between vitamin D and insulin sensitivity will require trials with repeated measures of these factors.

}, keywords = {Adiposity, Aged, Anthropometry, Cardiovascular Diseases, Cross-Sectional Studies, Exercise, Female, Humans, Hydroxycholecalciferols, Inflammation, Insulin, Insulin Resistance, Longitudinal Studies, Male, Middle Aged, Obesity, Risk Factors, Surveys and Questionnaires}, issn = {1532-8600}, doi = {10.1016/j.metabol.2013.07.008}, author = {Danziger, John and Biggs, Mary L and Niemi, Matt and Ix, Joachim H and Kizer, Jorge R and Djouss{\'e}, Luc and de Boer, Ian H and Siscovick, David S and Kestenbaum, Bryan and Mukamal, Kenneth J} }