Circulating 25-hydroxyvitamin D Is Associated With Insulin Resistance Cross-Sectionally but Not Longitudinally in Older Adults: The Cardiovascular Health Study

Metabolism. 2013 Dec;62(12):1788-94. doi: 10.1016/j.metabol.2013.07.008. Epub 2013 Aug 27.

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: 25(OH)D; 25-hydroxyvitamin D; BMI; Body mass index; CES-D; CHS; Cardiovascular Health Study; Center for Epidemiological Studies Depression; HOMA; Homeostasis Model Assessment; Insulin resistance; Vitamin D.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adiposity
  • Aged
  • Anthropometry
  • Cardiovascular Diseases / epidemiology
  • Cross-Sectional Studies
  • Exercise / physiology
  • Female
  • Humans
  • Hydroxycholecalciferols / blood*
  • Inflammation / blood
  • Insulin / metabolism
  • Insulin Resistance / physiology*
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Obesity / blood
  • Obesity / metabolism
  • Risk Factors
  • Surveys and Questionnaires

Substances

  • Hydroxycholecalciferols
  • Insulin