Serum 25‐hydroxyvitamin D and insulin resistance in people at high risk of cardiovascular disease: a euglycaemic hyperinsulinaemic clamp study

Abstract

word count: 210References: 28 Number of tables: 3 Number of figures: 2Trial Registration: NCT00874341, ClinicalTrials.gov pg. 3 ABSTRACT CONTEXT: In observational studies low serum concentration is associated with an increased risk of type 2 diabetes mellitus (DM).Increasing serum 25-OHD may have beneficial effects on insulin resistance or betacell function. Cross-sectional studies utilising sub-optimal methods for assessment of insulin sensitivity and serum 25-OHD concentration provide conflicting results. OBJECTIVE:This study examined the relationship between serum 25-OHD concentration and insulin resistance in healthy overweight individuals at increased risk of cardiovascular disease, using optimal assessment techniques. CONCLUSIONS:In this study using optimal assessment techniques to measure 25-OHD concentration, insulin sensitivity and body composition, there was no association between serum 25-OHD concentration and insulin resistance in healthy, overweight individuals at high risk of developing cardiovascular disease. This study suggests the documented inverse association between serum 25-OHD concentration pg. 4 and risk of type 2 DM is not mediated by a relationship between serum 25-OHD concentration and insulin resistance.

Maternal vitamin D and markers of glycaemia during pregnancy in the Belfast centre of the Hyperglycaemia and Adverse Pregnancy Outcome study

“…Weak associations were observed between vitamin D and HOMA-b, while the association with fasting plasma glucose approached significance. Overall, these results suggest that vitamin D does not have a role in the development of GDM during pregnancy and are consistent with evolving data in the non-pregnant context [35,36]. The positive association of 25OHD and HDL merits further investigation to confirm the association and to explore possible biological mechanisms.…”

Insulin-sensitizing effects of vitamin D repletion mediated by adipocyte vitamin D receptor: Studies in humans and mice

“…Conversely, several studies showed positive associations between serum vitamin D levels and peripheral insulin sensitivity in both pre-diabetic and T2D subjects [ 79 , 80 ]. Four out of six cross-sectional studies using euglycemic stepped hyperinsulinemic clamps, considered the gold standard for measuring insulin sensitivity, showed positive associations between vitamin D levels and insulin sensitivity in non-diabetic subjects [ [81] , [82] , [83] , [84] , [85] , [86] ]. Prospective studies also revealed beneficial effects of vitamin D supplementation on insulin sensitivity [ 87 , 88 ], including a meta-analysis of prospective cohort studies [ 17 , 89 , 90 ].…”