Dataset Information

Consistent Inverse Associations of Total, "Bioavailable", Free, and "Non-Bioavailable" Vitamin D with Incidence of Diabetes among Older Adults with Lower Baseline HbA_1c (≤6%) Levels.

ABSTRACT:

Background

Serum 25-hydroxyvitamin (25(OH)D) levels are inversely associated with risk of diabetes. The "free hormone hypothesis" suggests potential effects to be mainly related to concentrations of "bioavailable" and free rather than total 25(OH)D. We assessed associations of serum concentrations of vitamin D-binding protein (VDBP), as well as total "bioavailable", complementary "non-bioavailable", and free 25(OH)D, with the risk of developing diabetes among non-diabetic older adults in a large population-based cohort study in Germany.

Methods

We included 4841 non-diabetic older adults aged 50-75 years at the baseline exam from the ESTHER cohort conducted in Saarland, Germany, in 2001-2002. Concentrations of "bioavailable" and free 25(OH)D were derived from serum concentrations of VDBP, total 25(OH)D, and albumin. Incidence of diabetes was ascertained during up to 14 years of follow-up. Associations were quantified by multivariable Cox proportional hazards regression models with comprehensive confounder adjustment.

Results

During a median follow-up of 10.6 years, 837 non-diabetic participants developed diabetes. We observed similar inverse associations with developing diabetes for VDBP (hazard ratio (HR) for lowest versus highest quintile: 1.37, 95% confidence interval (CI): 1.09, 1.72), total 25(OH)D (HR: 1.31, 95% CI: 1.03, 1.66), and "non-bioavailable" 25(OH)D (HR: 1.30, 95% CI: 1.02, 1.65). Associations were smaller and statistically insignificant for "bioavailable" and free 25(OH)D. However, associations of total "non-bioavailable", "bioavailable", and free 25(OH)D with incidence of diabetes were much stronger among, and essentially restricted to, participants with lower baseline HbA_1c (≤6%) levels.

Conclusions

This large prospective cohort study of older Caucasian adults, in agreement with results from randomized trials and Mendelian randomization studies, supports a protective effect of vitamin D against development of diabetes. The "free hormone theory" may not be relevant in this context. However, our results underline the importance of adequate vitamin D status among those who have not yet shown any sign of impaired glucose tolerance.

SUBMITTER: Zhu A

PROVIDER: S-EPMC9413175 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature

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Consistent Inverse Associations of Total, "Bioavailable", Free, and "Non-Bioavailable" Vitamin D with Incidence of Diabetes among Older Adults with Lower Baseline HbA<sub>1c</sub> (≤6%) Levels.

Zhu Anna A Kuznia Sabine S Niedermaier Tobias T Holleczek Bernd B Schöttker Ben B Brenner Hermann H

Nutrients 20220811 16

<h4>Background</h4>Serum 25-hydroxyvitamin (25(OH)D) levels are inversely associated with risk of diabetes. The "free hormone hypothesis" suggests potential effects to be mainly related to concentrations of "bioavailable" and free rather than total 25(OH)D. We assessed associations of serum concentrations of vitamin D-binding protein (VDBP), as well as total "bioavailable", complementary "non-bioavailable", and free 25(OH)D, with the risk of developing diabetes among non-diabetic older adults in ...[more]

PMID: 36014788

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Project description:Aims/hypothesisThe aim of the study was to evaluate longitudinal associations between HbA1c levels, diabetes status and subsequent cognitive decline over a 10 year follow-up period.MethodsData from wave 2 (2004-2005) to wave 7 (2014-2015) of the English Longitudinal Study of Ageing (ELSA) were analysed. Cognitive function was assessed at baseline (wave 2) and reassessed every 2 years at waves 3-7. Linear mixed models were used to evaluate longitudinal associations.ResultsThe study comprised 5189 participants (55.1% women, mean age 65.6 ± 9.4 years) with baseline HbA1c levels ranging from 15.9 to 126.3 mmol/mol (3.6-13.7%). The mean follow-up duration was 8.1 ± 2.8 years and the mean number of cognitive assessments was 4.9 ± 1.5. A 1 mmol/mol increment in HbA1c was significantly associated with an increased rate of decline in global cognitive z scores (-0.0009 SD/year, 95% CI -0.0014, -0.0003), memory z scores (-0.0005 SD/year, 95% CI -0.0009, -0.0001) and executive function z scores (-0.0008 SD/year, 95% CI -0.0013, -0.0004) after adjustment for baseline age, sex, total cholesterol, HDL-cholesterol, triacylglycerol, high-sensitivity C-reactive protein, BMI, education, marital status, depressive symptoms, current smoking, alcohol consumption, hypertension, CHD, stroke, chronic lung disease and cancer. Compared with participants with normoglycaemia, the multivariable-adjusted rate of global cognitive decline associated with prediabetes and diabetes was increased by -0.012 SD/year (95% CI -0.022, -0.002) and -0.031 SD/year (95% CI -0.046, -0.015), respectively (p for trend <0.001). Similarly, memory, executive function and orientation z scores showed an increased rate of cognitive decline with diabetes.Conclusions/interpretationSignificant longitudinal associations between HbA1c levels, diabetes status and long-term cognitive decline were observed in this study. Future studies are required to determine the effects of maintaining optimal glucose control on the rate of cognitive decline in people with diabetes.

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Dataset Information

Consistent Inverse Associations of Total, "Bioavailable", Free, and "Non-Bioavailable" Vitamin D with Incidence of Diabetes among Older Adults with Lower Baseline HbA_1c (≤6%) Levels.

Background

Methods

Results

Conclusions

Publications

Consistent Inverse Associations of Total, "Bioavailable", Free, and "Non-Bioavailable" Vitamin D with Incidence of Diabetes among Older Adults with Lower Baseline HbA<sub>1c</sub> (≤6%) Levels.

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OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Consistent Inverse Associations of Total, "Bioavailable", Free, and "Non-Bioavailable" Vitamin D with Incidence of Diabetes among Older Adults with Lower Baseline HbA1c (≤6%) Levels.

Background

Methods

Results

Conclusions

Publications

Consistent Inverse Associations of Total, "Bioavailable", Free, and "Non-Bioavailable" Vitamin D with Incidence of Diabetes among Older Adults with Lower Baseline HbA<sub>1c</sub> (≤6%) Levels.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Consistent Inverse Associations of Total, "Bioavailable", Free, and "Non-Bioavailable" Vitamin D with Incidence of Diabetes among Older Adults with Lower Baseline HbA_1c (≤6%) Levels.