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Vitamin D, insulin secretion, sensitivity, and lipids: results from a case-control study and a randomized controlled trial using hyperglycemic clamp technique.

Grimnes G, Figenschau Y, Almås B, Jorde R - Diabetes (2011)

Bottom Line: A final hyperglycemic clamp was then performed.After supplementation, serum 25(OH)D was 142.7 ± 25.7 and 42.9 ± 17.3 nmol/L in 49 of 51 completing participants randomized to vitamin D and 45 of 53 randomized to placebo, respectively.At the end of the study, there were no statistically significant differences in the outcome variables between the two groups.

View Article: PubMed Central - PubMed

Affiliation: Tromsø Endocrine Research Group, Department of Clinical Medicine, University of Tromsø, Tromsø, Norway. guri.grimnes@unn.no

ABSTRACT

Objective: Vitamin D deficiency is associated with an unfavorable metabolic profile in observational studies. The intention was to compare insulin sensitivity (the primary end point) and secretion and lipids in subjects with low and high serum 25(OH)D (25-hydroxyvitamin D) levels and to assess the effect of vitamin D supplementation on the same outcomes among the participants with low serum 25(OH)D levels.

Research design and methods: Participants were recruited from a population-based study (the Tromsø Study) based on their serum 25(OH)D measurements. A 3-h hyperglycemic clamp was performed, and the participants with low serum 25(OH)D levels were thereafter randomized to receive capsules of 20,000 IU vitamin D(3) or identical-looking placebo twice weekly for 6 months. A final hyperglycemic clamp was then performed.

Results: The 52 participants with high serum 25(OH)D levels (85.6 ± 13.5 nmol/L [mean ± SD]) had significantly higher insulin sensitivity index (ISI) and lower HbA(1c) and triglycerides (TGs) than the 108 participants with low serum 25(OH)D (40.3 ± 12.8 nmol/L), but the differences in ISI and TGs were not significant after adjustments. After supplementation, serum 25(OH)D was 142.7 ± 25.7 and 42.9 ± 17.3 nmol/L in 49 of 51 completing participants randomized to vitamin D and 45 of 53 randomized to placebo, respectively. At the end of the study, there were no statistically significant differences in the outcome variables between the two groups.

Conclusions: Vitamin D supplementation to apparently healthy subjects with insufficient serum 25(OH)D levels does not improve insulin sensitivity or secretion or serum lipid profile.

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Related in: MedlinePlus

First phase insulin release (AUC 0–10 min), second phase insulin release (AUC 120–180 min), M, and ISI from a 3-h hyperglycemic clamp comparing participants with low and high serum 25(OH)D at baseline, and at baseline and after completion in the RCT. Data are geometric means. A: Subjects with low serum 25(OH)D (n = 104) (black bars) and high serum 25(OH)D (n = 50) (white bars) levels at baseline. B: Subjects with low serum 25(OH)D (n = 49) randomized to high dose vitamin D3 at baseline (black bars) and after 6 months (white bars). C: Subjects with low serum 25(OH)D (n = 45) randomized to placebo at baseline (black bars) and after 6 months (white bars). *P < 0.05.
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Figure 3: First phase insulin release (AUC 0–10 min), second phase insulin release (AUC 120–180 min), M, and ISI from a 3-h hyperglycemic clamp comparing participants with low and high serum 25(OH)D at baseline, and at baseline and after completion in the RCT. Data are geometric means. A: Subjects with low serum 25(OH)D (n = 104) (black bars) and high serum 25(OH)D (n = 50) (white bars) levels at baseline. B: Subjects with low serum 25(OH)D (n = 49) randomized to high dose vitamin D3 at baseline (black bars) and after 6 months (white bars). C: Subjects with low serum 25(OH)D (n = 45) randomized to placebo at baseline (black bars) and after 6 months (white bars). *P < 0.05.

Mentions: The serum 25(OH)D levels in the sixth Tromsø Study were 33.9 ± 5.5 for case subjects and 77.6 ± 4.9 nmol/L for control subjects, with corresponding baseline values 40.3 ± 12.8 and 85.6 ± 13.5 nmol/L (Table 1). Median time (5th to 95th percentiles) between attendance date in the sixth Tromsø Study and baseline was 13 months (8–26). As expected according to the inclusion procedure, there were no significant differences between case and control subjects at baseline regarding age, BMI, or sex. Leisure-time physical activity level was significantly higher in control subjects, as were use of vitamin D supplementation, sun bed use, and sunny holidays during the past 3 months. Serum PTH, TGs, and HbA1c were significantly higher in case subjects, while ISI was lower (Table 1 and Fig. 3). These results were similar also when statin users were excluded (data not shown).


Vitamin D, insulin secretion, sensitivity, and lipids: results from a case-control study and a randomized controlled trial using hyperglycemic clamp technique.

Grimnes G, Figenschau Y, Almås B, Jorde R - Diabetes (2011)

First phase insulin release (AUC 0–10 min), second phase insulin release (AUC 120–180 min), M, and ISI from a 3-h hyperglycemic clamp comparing participants with low and high serum 25(OH)D at baseline, and at baseline and after completion in the RCT. Data are geometric means. A: Subjects with low serum 25(OH)D (n = 104) (black bars) and high serum 25(OH)D (n = 50) (white bars) levels at baseline. B: Subjects with low serum 25(OH)D (n = 49) randomized to high dose vitamin D3 at baseline (black bars) and after 6 months (white bars). C: Subjects with low serum 25(OH)D (n = 45) randomized to placebo at baseline (black bars) and after 6 months (white bars). *P < 0.05.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3198082&req=5

Figure 3: First phase insulin release (AUC 0–10 min), second phase insulin release (AUC 120–180 min), M, and ISI from a 3-h hyperglycemic clamp comparing participants with low and high serum 25(OH)D at baseline, and at baseline and after completion in the RCT. Data are geometric means. A: Subjects with low serum 25(OH)D (n = 104) (black bars) and high serum 25(OH)D (n = 50) (white bars) levels at baseline. B: Subjects with low serum 25(OH)D (n = 49) randomized to high dose vitamin D3 at baseline (black bars) and after 6 months (white bars). C: Subjects with low serum 25(OH)D (n = 45) randomized to placebo at baseline (black bars) and after 6 months (white bars). *P < 0.05.
Mentions: The serum 25(OH)D levels in the sixth Tromsø Study were 33.9 ± 5.5 for case subjects and 77.6 ± 4.9 nmol/L for control subjects, with corresponding baseline values 40.3 ± 12.8 and 85.6 ± 13.5 nmol/L (Table 1). Median time (5th to 95th percentiles) between attendance date in the sixth Tromsø Study and baseline was 13 months (8–26). As expected according to the inclusion procedure, there were no significant differences between case and control subjects at baseline regarding age, BMI, or sex. Leisure-time physical activity level was significantly higher in control subjects, as were use of vitamin D supplementation, sun bed use, and sunny holidays during the past 3 months. Serum PTH, TGs, and HbA1c were significantly higher in case subjects, while ISI was lower (Table 1 and Fig. 3). These results were similar also when statin users were excluded (data not shown).

Bottom Line: A final hyperglycemic clamp was then performed.After supplementation, serum 25(OH)D was 142.7 ± 25.7 and 42.9 ± 17.3 nmol/L in 49 of 51 completing participants randomized to vitamin D and 45 of 53 randomized to placebo, respectively.At the end of the study, there were no statistically significant differences in the outcome variables between the two groups.

View Article: PubMed Central - PubMed

Affiliation: Tromsø Endocrine Research Group, Department of Clinical Medicine, University of Tromsø, Tromsø, Norway. guri.grimnes@unn.no

ABSTRACT

Objective: Vitamin D deficiency is associated with an unfavorable metabolic profile in observational studies. The intention was to compare insulin sensitivity (the primary end point) and secretion and lipids in subjects with low and high serum 25(OH)D (25-hydroxyvitamin D) levels and to assess the effect of vitamin D supplementation on the same outcomes among the participants with low serum 25(OH)D levels.

Research design and methods: Participants were recruited from a population-based study (the Tromsø Study) based on their serum 25(OH)D measurements. A 3-h hyperglycemic clamp was performed, and the participants with low serum 25(OH)D levels were thereafter randomized to receive capsules of 20,000 IU vitamin D(3) or identical-looking placebo twice weekly for 6 months. A final hyperglycemic clamp was then performed.

Results: The 52 participants with high serum 25(OH)D levels (85.6 ± 13.5 nmol/L [mean ± SD]) had significantly higher insulin sensitivity index (ISI) and lower HbA(1c) and triglycerides (TGs) than the 108 participants with low serum 25(OH)D (40.3 ± 12.8 nmol/L), but the differences in ISI and TGs were not significant after adjustments. After supplementation, serum 25(OH)D was 142.7 ± 25.7 and 42.9 ± 17.3 nmol/L in 49 of 51 completing participants randomized to vitamin D and 45 of 53 randomized to placebo, respectively. At the end of the study, there were no statistically significant differences in the outcome variables between the two groups.

Conclusions: Vitamin D supplementation to apparently healthy subjects with insufficient serum 25(OH)D levels does not improve insulin sensitivity or secretion or serum lipid profile.

Show MeSH
Related in: MedlinePlus