The inconsistent results on the effects of vitamin D on muscle strength reported by intervention trials may partly be explained by inclusion of vitamin D sufficient individuals. The main objective ...was to study whether vitamin D supplementation will improve muscle strength in men and women with low serum vitamin D status, as measured by 25-hydroxyvitamin D (25(OH)D) at baseline.
417 men and women aged 40-80 years were included and randomized to receive a loading dose of 100 000 IU (2500 ug) vitamin D3 followed by 20 000 IU (500 ug)/week, or placebo. Muscle strength was tested by dynamometers at baseline and after four months.
Serum 25(OH)D levels increased from 32.6±11.1 nmol/l to 88.8±19.4 nmol/l (p<0.01) in the vitamin D group, while remaining low in the placebo group (baseline and final levels at 35.1±13.6 nmol/l and 30.7 ±9.7 nmol/l respectively). Muscle strength (hip flexion, biceps flexion, pectorals and handgrip strength) did not change in any of the groups. The results were the same in analyses stratified on sex, 25(OH)D above/below 25 nmol/L (10 ng/ml); smoking status; and BMI above/below 27 kg/m2.
These data does not support vitamin D supplementation for improving muscle strength.
A large number of observational studies have reported harmful effects of low 25-hydroxyvitamin D (25OHD) levels on non-skeletal outcomes. We performed a systematic quantitative review on ...characteristics of randomized clinical trials (RCTs) included in meta-analyses (MAs) on non-skeletal effects of vitamin D supplementation.
We identified systematic reviews (SR) reporting summary data in terms of MAs of RCTs on selected non-skeletal outcomes. For each outcome, we summarized the results from available SRs and scrutinized included RCTs for a number of predefined characteristics. We identified 54 SRs including data from 210 RCTs. Most MAs as well as the individual RCTs reported null-findings on risk of cardiovascular diseases, type 2 diabetes, weight-loss, and malignant diseases. Beneficial effects of vitamin D supplementation was reported in 1 of 4 MAs on depression, 2 of 9 MAs on blood pressure, 3 of 7 MAs on respiratory tract infections, and 8 of 12 MAs on mortality. Most RCTs have primarily been performed to determine skeletal outcomes, whereas non-skeletal effects have been assessed as secondary outcomes. Only one-third of the RCTs had low level of 25OHD as a criterion for inclusion and a mean baseline 25OHD level below 50 nmol/L was only present in less than half of the analyses.
Published RCTs have mostly been performed in populations without low 25OHD levels. The fact that most MAs on results from RCTs did not show a beneficial effect does not disprove the hypothesis suggested by observational findings on adverse health outcomes of low 25OHD levels.
High intake of sugar-sweetened beverages (SSB) has been associated with weight gain and chronic disease. The objective of this paper was to study the intake of SSB and characteristics associated with ...SSB intake in adolescents from Troms, Norway. We present results from a cross-sectional analysis from the Tromsø Study:
, with 426 female and 444 male students aged 15⁻17 years (93% participation rate). Descriptive statistics and logistic regression analyses were performed. Among females, 31.8% drank at least one glass of SSB per day on average, compared to 61.0% among males. The adjusted OR (odds ratio) of daily SSB drinking for males vs. females was 3.74 (95% CI (confidence interval) 2.68⁻5.22). Other dietary habits such as eating snacks, drinking artificially sweetened beverages, fruit juice, and seldom eating breakfast were associated with higher odds for daily SSB drinking, as was daily snuffing. Weight class was not associated with daily SSB drinking. Students in vocational studies, particularly males tended to be more likely to be daily SSB drinkers. The prevalence of participants who on average were daily drinkers was higher than in national studies. We have identified several possible targets for interventions. Clustering of unhealthy behaviours and tendencies to socioeconomic differences are of particular concern.
Purpose
The serum 25-hydroxyvitamin D (25(OH)D) levels are lower in obese than lean subjects. The present study examines the cross-sectional and longitudinal relations between body mass index (BMI) ...and serum 25(OH)D, and the serum 25(OH)D response to vitamin D supplementation in relation to BMI.
Methods
The Tromsø study is a longitudinal population-based multipurpose study. The fourth survey was conducted in 1994 and the sixth in 2008. The intervention study was a 1-year placebo-controlled randomized intervention trial, where the results from the 93 subjects given 40,000 IU per week are presented.
Results
A total of 10,229 subjects were included in the 2008 cross-sectional study. There was a significant negative association between serum 25(OH)D levels and BMI which was also present during the winter months. Serum 25(OH)D levels varied through seasons, but not BMI. In the longitudinal study from 1994 to 2008 which included 2,656 subjects, change in BMI was a significant negative predictor of change in 25(OH)D. In the intervention study, there was a significant and negative correlation between BMI and serum 25(OH)D both at baseline and at the end of the study. The increase in serum 25(OH)D after 1 year was significantly and inversely related to baseline BMI.
Conclusions
We have confirmed the strong association between serum 25(OH)D and BMI. The very obese need higher vitamin D doses than lean subjects to achieve the same serum 25(OH)D levels.
Abstract
Background
There are indications that an increased intake of calcium has a vitamin D sparing effect, which might be explained by a decreased catabolism of 25-hydroxyvitamin D (25(OH)D). ...However, there are only a few studies where this has been examined.
Method
In the seventh survey of the Tromsø study, serum 25(OH)D and parathyroid hormone were measured, and questionnaires on calcium and vitamin D intakes filled in.
Results
There were significant interactions between sex, calcium and vitamin D intakes regarding serum 25(OH)D level. The analyses were therefore done stratified. In males there was, regardless of vitamin D intake, a significant decrease in serum 25(OH)D with increasing calcium intake. The difference in serum 25(OH)D between those with the highest and lowest calcium intakes was approximately 10%. In the females, there was in subjects with low vitamin D intake (< 7 μg/d) a significant increase in serum 25(OH)D with increasing calcium intake, which could not be explained by secondary hyperparathyroidism. In females with higher vitamin D intakes, increasing calcium intake was associated with lower serum 25(OH)D levels.
Conclusions
There is, at least in subjects with an adequate vitamin D intake, a negative association between calcium intake and serum 25(OH)D.
ObjectiveEcologic and observational studies have suggested an association between serum 25-hydroxyvitamin D (25(OH)D) levels and cardiovascular disease (CVD) risk factors, CVD mortality, and cancer ...mortality. Based on this, low serum 25(OH)D levels should be associated with higher all-cause mortality in a general population. This hypothesis was tested in the present study.DesignThe Tromsø study is a longitudinal population-based multipurpose study initiated in 1974 with focus on lifestyle-related diseases. Our data are based on the fourth Tromsø study carried out in 1994–1995.MethodsInformation about death and cause of death was registered by obtaining information from the National Directory of Residents and the Death Cause Registry. Serum 25(OH)D was measured in 7161 participants in the fourth Tromsø study. Results are presented for smokers (n=2410) and non-smokers (n=4751) separately as our immunoassay seems to overestimate 25(OH)D levels for smokers.ResultsDuring a mean 11.7 years of follow-up, 1359 (19.0%) participants died. In multivariate regression models, there was a significantly increased risk of all-cause mortality (hazard ratio (HR) 1.32, confidence interval (CI) 1.07–1.62) among non-smoking participants in the lowest 25(OH)D quartile when compared with participants in the highest quartile. Equivalent results for smokers were not significant (HR 1.06, CI 0.83–1.35).ConclusionsLow serum 25(OH)D levels were associated with increased all-cause mortality for non-smokers, but the results did not reach statistical significance for smokers. However, low 25(OH)D levels are known to be associated with impaired general health, and randomized controlled studies are needed to address the question of causality.
Background: Low serum 25-hydroxyvitamin D (25(OH)D) levels have consistently been associated with hypertension. During the last decades there has been an unexplained reduction in blood pressure (BP) ...in Western countries. We therefore examined the relation between serum 25(OH)D and BP in the 7th survey of the Tromsø study 2015/2016.
Methods: Blood pressure and serum 25(OH)D were measured and life-style factors registered in 15,951 subjects not using BP medication.
Results: In unadjusted analyses there was a significant negative association between serum 25(OH)D and systolic and diastolic BP that disappeared after adjusting for relevant confounders. This finding is in contrast to our previous reports on 25(OH)D and BP. We therefore cross-sectionally re-analyzed non-smoking (due to interference by smoking in the 25(OH)D assay) subjects not using BP medication from the 4th survey in 1994/1995 (n = 4108), 6th survey in 2007/2008 (n = 7553) and 7th survey 2015/2016 (n = 13,413). Adjusting for age and BMI, there were significant inverse relations between BP and 25(OH)D in the 4th, to a lesser degree in the 6th, and none in the 7th survey. For males the age- and BMI-adjusted differences in systolic BP between those with serum 25(OH)D < 25 nmol/L versus serum 25(OH)D > 100 nmol/L were 6.2 mmHg, 4.1 mmHg and −0.1 mmHg, for the 4th, 6th and 7th surveys, respectively.
Conclusions: Concomitant with a substantial reduction in BP from 1994 to 2015, there has been a loss of relation between 25(OH)D and BP which is hard to explain.
Vitamin D and cognitive function: The Tromsø Study Jorde, Rolf; Mathiesen, Ellisiv Bøgeberg; Rogne, Sigbjørn ...
Journal of the neurological sciences,
08/2015, Letnik:
355, Številka:
1
Journal Article
Recenzirano
Abstract Background and purpose There are indications that vitamin D may be important for more than skeletal health, including cognitive function. Methods The study was performed in Tromsø, Northern ...Norway (The Tromsø Study). In a cross-sectional study serum 25-hydroxyvitamin D (25(OH)D) was measured and cognitive function (word recall, digit–symbol coding, finger tapping, Mini Mental State Examination) tested in 4624 subjects; in a prospective study serum 25(OH)D was measured in samples from 1994 and compared to cognitive function tested in 3436 subjects in 2001 and 2044 subjects in 2007; and in a Mendelian randomization study single nucleotide polymorphisms (SNPs) related to vitamin D were evaluated versus cognitive function in 5980 subjects. Results In the cross-sectional study all tests were positively associated with serum 25(OH)D levels with ~ 5% better performance in subjects in the highest versus lowest serum 25(OH)D quartile. This relation was only seen in subjects older than 65 years. After full adjustment for season, age, gender, body mass index, blood pressure, physical activity and education, the relation was only significant for finger tapping. In the prospective study, serum 25(OH)D from 1994 similarly predicted cognitive function 7–13 years later. In the Mendelian randomization study, only one SNP in the VDR gene (Apal, rs7975232) was significantly associated with cognition (word recall and digit–symbol coding). Conclusions There is an association between serum 25(OH)D and cognition, but randomized controlled trials are needed to establish causality.
The balance between bone resorption and formation may be assessed by measurement of bone turnover markers (BTMs), like carboxyl-terminal cross-linked telopeptide of type 1 collagen (CTX-1) and ...procollagen type 1 amino-terminal propeptide (P1NP). Smoking has been shown to influence bone turnover and to reduce bone mass density (BMD), the exact mechanism for this is, however, not settled. In this post-hoc study including 406 subjects (mean age 51.9 years), we aimed to study the impact of smoking on bone turnover. Moreover, we wanted to assess the inter-correlation between substances regulating bone metabolism and BTMs, as well as tracking over time. BMD measurements and serum analyses of CTX-1, P1NP, osteoprotegerin (OPG), receptor activator of nuclear factor ĸB ligand (RANKL), Dickkopf-1 (DKK1), sclerostin, tumor necrosis factor-α (TNF-α), and leptin were performed. Repeated serum measurements were made in 195 subjects after four months. Adjustments were made for sex, age, body mass index (BMI), smoking status, insulin resistance, serum calcium, parathyroid hormone, 25-hydroxyvitamin D and creatinine. Smokers had higher levels of DKK1 and OPG, and lower levels of RANKL, as reflected in lower BTMs and BMD compared to non-smokers. There were strong and predominantly positive inter-correlations between BTMs and the other substances, and there was a high degree of tracking with Spearman's rho from 0.72 to 0.92 (P < 0.001) between measurements four months apart. In conclusion, smokers exhibited higher levels of DKK1 and OPG and a lower bone turnover than did non-smokers. The strong inter-correlations between the serum parameters illustrate the coupling between bone resorption and formation and crosstalk between cells.
Low vitamin D status is common in Europe. The major source of vitamin D in humans is ultraviolet B (UVB)-induced dermal synthesis of cholecalciferol, whereas food sources are believed to play a ...lesser role. Our objectives were to assess UVB availability (Jm(-2)) across several European locations ranging from 35° N to 69° N, and compare these UVB data with representative population serum 25-hydroxyvitamin D (25(OH)D) data from Ireland (51-54° N), Iceland (64° N) and Norway (69° N), as exemplars. Vitamin D-effective UVB availability was modelled for nine European countries/regions using a validated UV irradiance model. Standardized serum 25(OH)D data was accessed from the EC-funded ODIN project. The results showed that UVB availability decreased with increasing latitude (from 35° N to 69° N), while all locations exhibited significant seasonal variation in UVB. The UVB data suggested that the duration of vitamin D winters ranged from none (at 35° N) to eight months (at 69° N). The large seasonal fluctuations in serum 25(OH)D in Irish adults was much dampened in Norwegian and Icelandic adults, despite considerably lower UVB availability at these northern latitudes but with much higher vitamin D intakes. In conclusion, increasing the vitamin D intake can ameliorate the impact of low UVB availability on serum 25(OH)D status in Europe.
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