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Am J Clin Nutr. 2011 May 25. [Epub ahead of print]
Serum 25-hydroxyvitamin D concentrations are associated with prevalence of metabolic syndrome and various cardiometabolic risk factors in US children and adolescents based on assay-adjusted serum 25-hydroxyvitamin D data from NHANES 2001-2006.
Ganji V, Zhang X, Shaikh N, Tangpricha V.
Source

Division of Nutrition, School of Health Professions, College of Health and Human Sciences, Georgia State University, Atlanta, GA.
Abstract
BACKGROUND:

The effect of assay drifts over time on serum 25-hydroxyvitamin D [25(OH)D] concentrations were not accounted for in previous national survey studies. Thus, previously reported associations between 25(OH)D with cardiometabolic risk factors using data from NHANES were likely over- or underestimated. Moreover, associations between serum 25(OH)D and metabolic syndrome (MetSyn), insulin resistance (IR), and inflammation are unclear in children.
OBJECTIVE:

The relation between serum 25(OH)D and cardiometabolic risk factors in US children was investigated by using updated 25(OH)D data.
DESIGN:

This study was based on newly updated serum 25(OH)D data, which were released by the National Center for Health Statistics in November 2010. Data from 3 cycles of NHANES (2001-2002, 2003-2004, and 2005-2006) for 5867 adolescents, aged 12-19 y, were used to study the association, by multivariate-adjusted regression, between serum 25(OH)D and prevalence of MetSyn and several cardiometabolic risk factors.
RESULTS:

The likelihood of having MetSyn was significantly higher in the first tertile of serum 25(OH)D than in the third tertile of 25(OH)D (odds ratio: 1.71; 95% CI: 1.11, 2.65; P < 0.01). Waist circumference (P < 0.0001), systolic blood pressure (P = 0.01), and homeostatic model assessment-insulin resistance index (P = 0.001) were inversely related and HDL cholesterol (P < 0.0001) was directly related with serum 25(OH)D. No association was observed between 25(OH)D and C-reactive protein (P = 0.18).
CONCLUSIONS:

On the basis of assay-adjusted data, serum 25(OH)D was significantly associated with several cardiometabolic risk factors regardless of obesity. In children, given the negative outcomes associated with poor vitamin D status and MetSyn, consideration of vitamin D supplementation in reversing cardiometabolic risk factors appears to be warranted.

 

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This one, on LADA:

Diabetes Metab Res Rev. 2009 Jul;25(5):411-6.
Protective effects of 1-alpha-hydroxyvitamin D3 on residual beta-cell function in patients with adult-onset latent autoimmune diabetes (LADA).
Li X, Liao L, Yan X, Huang G, Lin J, Lei M, Wang X, Zhou Z.
Source

Diabetes Center, Institute of Metabolism and Endocrinology, Second Xiangya Hospital, Central South University, Changsha, China.
Abstract
BACKGROUND:

Previous in vitro and in vivo studies have demonstrated that vitamin D could prevent pancreatic beta-cell destruction and reduce the incidence of autoimmune diabetes. In children with type 1 diabetes, vitamin D treatment produces moderate protective effects on residual beta-cell function and has proven to be safe. Therefore, we hypothesized that vitamin D might have protective effects on beta-cell function in patients with latent autoimmune diabetes in adults (LADA), a form of slowly progressive autoimmune type 1 diabetes.
METHODS:

Thirty-five patients with LADA were randomly assigned to receive subcutaneous insulin alone (n = 18) or insulin plus 1-alpha-hydroxyvitamin D3 (1-alpha(OH)D3; 0.5 microg per day) (n = 17) for 1 year. Plasma C-peptide levels in fasting state (FCP) and 2 h after 75-g glucose load (PCP) were measured every 6 months with radioimmunoassay.
RESULTS:

Both FCP and PCP levels stayed steady in the insulin plus 1-alpha(OH)D3 group, while FCP decreased in insulin-alone group (P = 0.006) during the 12-month intervention. Seventy percent of patients treated with 1-alpha(OH)D3 maintained or increased their FCP concentrations after 1 year of treatment, while only 22% of patients treated with insulin alone maintained stable FCP levels (P < 0.01). Further analysis on LADA subgroups with different durations of diabetes demonstrated that islet beta-cell function was better preserved (as reflected by significantly higher FCP and PCP levels) in the 1-alpha(OH)D3 plus insulin group only in patients with diabetes duration no longer than 1 year. No severe side effects were observed in any group.
CONCLUSION:

Our data suggest that 1-alpha(OH)D3 plus insulin therapy can preserve pancreatic beta-cell function in patients with LADA.