Monica Sneve

Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: randomized double blind trial.

Objectives.  The objective of the present study was to examine the cross‐sectional relation between serum 25‐hydoxyvitamin D [25‐(OH) D] levels and depression in overweight and obese subjects and to assess the effect of vitamin D supplementation on depressive symptoms.

No significant effect on bone mineral density by high doses of vitamin D3 given to overweight subjects for one year.

BackgroundIn meta-analyses supplementation with vitamin D appears to reduce incidence of fractures, and in cross-sectional studies there is a positive association between serum 25-hydroxyvitamin D (25(OH)D) levels and bone mineral density (BMD). However, the effect of supplementation with high doses of vitamin D on BMD is more uncertain and could in theory have both positive and negative effects.MethodsThe study was a one year, double blind placebo-controlled intervention trial performed at the University Hospital of North Norway. 421 subjects, 21 - 70 years old, were included and 312 completed the study. The subjects were randomized to vitamin D3 40.000 IU per week (DD group), vitamin D3 20.000 IU per week (DP group), or placebo (PP group). All subjects were given 500 mg calcium daily. Serum 25(OH)D, osteoprotegrin (OPG), receptoractivator of nuclear factor-kappaB ligand (RANKL), and BMD at the lumbar spine and the hip were measured before and at the end of the study.ResultsAt baseline the mean serum 25(OH)D levels were 58 nmol/L (all subjects) and increased to 141 and 100 nmol/L in the DD and DP groups, respectively. After one year, no significant differences were found between the three groups regarding change in BMD, serum OPG or RANKL.ConclusionsSupplementation with high doses of vitamin D for one year does not appear to have a negative effect on BMD in healthy subjects. In order to disclose a positive effect, subjects with low BMD and/or low serum 25(OH)D levels need to be studied.Trial registrationThe trial was registered at ClinicalTrials.gov (NCT00243256).

Tracking of Serum 25-Hydroxyvitamin D Levels During 14 Years in a Population-based Study and During 12 Months in an Intervention Study

Low serum 25-hydroxyvitamin D (25(OH)D) levels are associated with risk factors for cardiovascular disease, and they also appear to predict later development of type 2 diabetes, cancer, and an increased mortality rate. These predictions are all based on a single 25(OH)D measurement, but so far there are no known reports on tracking of serum 25(OH)D levels. In the present Norwegian study, serum 25(OH)D levels were measured 1) in 2,668 subjects in the 1994 and 2008 Tromsø surveys and 2) every third month for 1 year in 94 subjects randomly assigned to placebo in a vitamin D intervention study. There was a marked seasonal variation in 25(OH)D, and, depending on the method of adjusting for season, the correlation coefficient between serum 25(OH)D measurements from 1994 and 2008 ranged from 0.42 to 0.52. In the 1-year intervention study, the correlation between baseline and 12-month values was 0.80. Apart from the effect of season, changes in weight, intake of vitamin D, and physical activity were related to change in serum 25(OH)D levels. Tracking of serum 25(OH)D appears similar to that for blood pressure and serum lipids, and it provides some support for the use of a single 25(OH)D measurement to predict future health outcomes.

No improvement in cardiovascular risk factors in overweight and obese subjects after supplementation with vitamin D3 for 1 year

Abstract.  Jorde R, Sneve M, Torjesen P, Figenschau Y (University of Tromsø, Tromsø; Medical Clinic University Hospital of North Norway, Tromsø; University Hospital of North Norway, Tromsø; Aker University Hospital, Oslo; University Hospital of North Norway, Tromsø; and University of Tromsø, Tromsø; Norway). No improvement in cardiovascular risk factors in overweight and obese subjects after supplementation with vitamin D3 for 1 year. J Intern Med 2010; 267:462–472.

Supplementation with cholecalciferol does not result in weight reduction in overweight and obese subjects

OBJECTIVE Investigate whether cholecalciferol supplementation leads to weight loss in overweight and obese adults. DESIGN Randomized double blind clinical trial with 20,000 IU cholecalciferol twice a week, or 20,000 IU once a week plus placebo, or placebo twice a week, for 12 months. All subjects were given 500 mg calcium supplementation. METHODS Four hundred and forty five healthy, overweight, and obese men and women (age 21-70 years, body mass index (BMI) 28.0-47.0 kg/m(2)). Body weight, fatness, and fat distribution parameters were measured by dual-energy X-ray absorptiometry and anthropometry, blood samples and 24-h urinary samples were collected. RESULTS At baseline, there were no significant differences between the groups, but there was a significant inverse relation between serum 25-hydroxyvitamin D (25(OH)D) levels and BMI, and a significant positive association between calorie intake and BMI. Three hundred and thirty four subjects completed the study. During the study, there was no significant change in weight, waist-to-hip ratio (WHR) or percentage body fat in any of the groups, nor between them. Parathyroid hormone decreased and 25(OH)D increased significantly in both groups receiving cholecalciferol, and serum levels of 25(OH)D stabilized after 3 months. Serum calcium was unchanged in all groups. Urinary calcium excretion increased in all groups, but there was no significant difference between the groups. Weekly dosage of 20,000-40,000 IU cholecalciferol for 12 months was associated with a low risk of adverse effects, at least in overweight and obese adults living at latitude 70 degrees N. CONCLUSION Significant weight reduction in overweight and obese subjects is unlikely to occur with cholecalciferol supplementation.

No effect of supplementation with cholecalciferol on cytokines and markers of inflammation in overweight and obese subjects.

Epidemiological studies indicate a relation between vitamin D status and autoimmune diseases, and in vitro studies demonstrate an effect of 1,25-dihydroxyvitamin D on immune activation. However, the relation between serum levels of 25-hydroxyvitamin D (25(OH)D) and the effect of vitamin D supplementation on serum levels of cytokines are not settled. In the present study interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12, IL-13, IL-17, intercellular adhesion molecule-1, interferon-gamma, monocyte chemotactic protein-1, and high sensitivity C-reactive protein, were measured in 437 overweight subjects and 324 completed a one year intervention with 40,000 IU vitamin D per week (group DD), 20,000 IU vitamin D per week (group DP), or placebo (group PP). No consistent relations between serum levels of the cytokines and 25(OH)D were found at baseline. In the intervention study, there was no difference in delta values (value at end of study minus value at inclusion) between the three groups regarding the individual cytokines measured, nor was there any indication of a polarization of the T cells towards a Th2 dominant type. In conclusion, we were not able to demonstrate with certainty any significant relation between serum levels of 25(OH)D levels and a number of cytokines and markers of inflammation.

Effects of a 1-year supplementation with cholecalciferol on interleukin-6, tumor necrosis factor-alpha and insulin resistance in overweight and obese subjects.

Insufficient vitamin D status has been linked to autoimmune diseases, cancer and metabolic disorders, like obesity and insulin resistance. In vitro and animal studies suggest that vitamin D may play a crucial role in immune activation and inflammation. The relation between vitamin D and pro-inflammatory cytokines is not completely established. Furthermore, it is not known if the effect of vitamin D on entities of metabolic syndrome is mediated through its effect on cytokines or other biomarkers. The objectives of this study were to investigate if there is a relationship between vitamin D status and such pro-inflammatory cytokines as tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6) and high sensitive C-reactive protein (hs-CRP) in patients with overweigh and obesity. We also proposed that the intervention with high dose of cholecalciferol may have effect on the cytokine levels and result in corresponding changes in the measures of insulin resistance (HOMA-IR and QUICKI). Serum levels of IL-6, TNF-α and hs-CRP were measured in 332 overweight and obese subjects who completed a 1-year randomised intervention with either 40,000 IU vitamin D (cholecalciferol) per week or 20,000 IU vitamin D per week, or placebo. We found significant associations between IL-6, TNF-α, vitamin D and insulin resistance indices at baseline. One year intervention with vitamin D decreased serum IL-6 levels; however hs-CRP levels were significantly increased. Neither measures of insulin resistance, nor TNF-α were influenced by a 1-year vitamin D supplementation.

Effect of smoking on the serum levels of 25-hydroxyvitamin D depends on the assay employed

OBJECTIVE Because we found higher serum 25-hydroxyvitamin D (25(OH)D) levels among smokers than among non-smokers with analyses using an electrochemiluminescence immunoassay (ECLIA) from Roche, the purpose of the present study was to examine whether this difference between smokers and non-smokers was maintained using other serum 25(OH)D assays. DESIGN A cross-sectional population-based study on 6932 participants from the Tromsø study, 1994-1995, and one validation study comparing six different serum 25(OH)D assays in 53 non-smokers and 54 smokers were performed. METHODS The association between smoking, season and serum 25(OH)D as measured by ECLIA (Roche) was assessed in the population-based study using general linear models with multivariate adjustments. In the validation study, serum levels of 25(OH)D were analysed with liquid chromatography coupled with mass spectrometry assay from two different laboratories, RIA (DiaSorin), HPLC, RIA (IDS) and ECLIA (Roche). T-tests and linear mixed model analyses were performed to compare the serum 25(OH)D levels in smokers and non-smokers within and between the methods. RESULTS In the population-based study, the serum levels of 25(OH)D using the ECLIA method were 51.9, 53.2 and 72.0 nmol/l in never, former and current smokers (P<0.01). In the validation study, the serum concentration of 25(OH)D was 10.3 nmol/l higher in smokers than in non-smokers (P<0.01) using the ECLIA (Roche), while non-significantly lower serum levels of 25(OH)D were found in smokers using the other five methods. CONCLUSIONS These two studies indicate that the ECLIA (Roche) overestimates serum 25(OH)D levels in smokers by unknown mechanisms. If confirmed, this might have clinical consequences, and the issue needs further exploration.

Cross-sectional study on the relationship between body mass index and smoking, and longitudinal changes in body mass index in relation to change in smoking status: The Tromsø Study

Aims: To evaluate the effects of smoking and other lifestyle factors on body mass index (BMI), and changes in BMI in relation to changes in smoking status. Methods: A cross-sectional study was performed on 10,920 males (3937 smokers) and 12,090 females (4343 smokers) who participated in the fourth Tromsø Study (performed in 1994—95). A longitudinal study was performed on 2364 males (732 smokers in 1994—95) and 2738 females (942 smokers in 1994—95) who participated in both the fourth and the fifth Tromsø studies (performed in 2001). Results: In the cross-sectional study, current smokers of both genders had a lower BMI (25.0±3.4 vs. 25.5±3.2 kg/m2 in males, and 23.9±3.9 vs. 25.3±4.6 kg/m 2 in females, p<0.01), a lower degree of physical activity, and a higher consumption of coffee and alcohol than never-smokers. We found a U-shaped relationship between number of cigarettes smoked per day and BMI, with the lowest BMI in those smoking 6— 10 cigarettes per day. Heavy smokers and never-smokers had similar BMI. In the longitudinal study, continuing smokers had a smaller increase in BMI than those who gave up smoking. In those who gave up smoking, there was a significant, positive relationship between number of cigarettes smoked in 1994—95 and increase in BMI. Conclusions: There is a U-shaped relationship between number of cigarettes smoked per day and BMI. Smoking cessation is associated with an increase in weight as compared to those who continue smoking.

The association between serum parathyroid hormone and bone mineral density, and the impact of smoking : the Tromsø Study

OBJECTIVE To explore the relation between serum parathyroid hormone (PTH) and bone mineral density (BMD), adjusted for lifestyle factors including smoking. DESIGN Cross-sectional study. METHODS The Tromsø Study is a population-based study performed for the fifth time in 2001. Serum PTH was measured and the subjects filled in a questionnaire covering lifestyle factors. BMD at the hip, distal and ultradistal forearm was measured. RESULTS Complete datasets were available in 1442 men and 1368 women. Age, body mass index and serum PTH were strong predictors of BMD level at the hip in both genders. No significant relation was seen between serum PTH and BMD at the distal or ultradistal forearm. When smokers and non-smokers were analysed separately, the relation between PTH and BMD at the hip was significant in current non-smokers only. In males, current non-smokers had significantly higher BMD at all three measurement sites compared with current smokers. Male former smokers had values in between current and never smokers. There was a significant and negative relation between number of years smoked and BMD at the hip. In male former smokers, there was an increase in BMD with increasing years since smoking cessation. CONCLUSION Serum PTH is negatively associated with BMD at the hip, and the relation seems to be masked, or diminished, by smoking. Smoking reduces BMD at the hip, distal and ultradistal forearm in males, and the effect appears to be mainly time and not dose dependent.