No associations of 25-hydroxycholecalciferol and parathyroid hormone concentrations with calcaneal bone characteristics in community-dwelling elderly subjects: A cross-sectional study

Objective

This study examined the associations of 25-hydroxycholecalciferol [25(OH)D₃] and intact parathyroid hormone (iPTH) concentrations with bone status parameters in elderly subjects.

Design/Setting

Cross-sectional data based on the follow-up 2008 of the longitudinal study on nutrition and health status of senior citizens in Giessen, Germany.

Participants

One hundred eighty-eight independently living subjects aged 66–96 years.

Measurements

Serum concentrations of 25(OH)D₃, iPTH, N-terminal propeptide of type 1 collagen (P1NP) and activity of alkaline phosphatase (ALP) were assessed. Broadband ultrasound attenuation, speed of sound and stiffness index were determined by calcaneal quantitative ultrasound (QUS). Multiple linear regression analyses were performed to analyse associations of 25(OH)D₃ and iPTH with bone status parameters.

Results

Median (range) 25(OH)D₃ and iPTH concentrations were 62.8 (29.9–106.7) nmol/L and 4.6 (1.3–21.0) pmol/L, respectively. Neither 25(OH)D₃ nor iPTH was associated with calcaneal bone characteristics measured by QUS, whereas negative associations between 25(OH)D₃ and bone formation markers (P1NP and ALP) were found. In a sub analysis, 25(OH)D₃ was negatively associated with ALP only in subjects with iPTH concentrations > 4.59 pmol/L.

Conclusion

The present study provides no evidence for independent associations of 25(OH)D₃ and iPTH with calcaneal bone characteristics in community-dwelling elderly subjects with 25(OH)D₃ concentrations between 30 and 107 nmol/L. However, 25(OH)D₃ interacts with bone formation markers, particularly in subjects with high iPTH concentrations.

     

Is a daily supplementation with 40 microgram vitamin D3 sufficient? A randomised controlled trial

Purpose

The effect of 40?μg (1,600?IU) per day of vitamin D₃ on serum 25-hydroxyvitamin D (25(OH)D) and markers of bone and mineral metabolism was evaluated.

Methods

This intervention study was designed as a double-blind randomised controlled trial. Forty-five community-dwelling subjects (32 females), age 55–84?years, at 58° North latitude were supplemented for 1?year with 40?μg vitamin D₃ plus 1,000?mg calcium per day, or with 1,000?mg calcium per day for controls. Safety parameters and 25(OH)D, intact parathyroid hormone (PTH), ionized calcium, bone-specific alkaline phosphatase (BALP), and tartrate-resistant acid phosphatase isoform 5b (TRACP5b) were measured over the study period.

Results

All subjects supplemented with vitamin D₃ reached a 25(OH)D level above 50?nmol/L. Mean (SD) serum 25(OH)D increased from 50.4 (13.5) nmol/L to 84.2 (17.5) nmol/L, range 55.0–125.0?nmol/L in the vitamin D₃ supplemented group and the corresponding levels for the control group were 47.3 (14.1) nmol/L and 45.7 (13.4) nmol/L, range 26.0–73.0?nmol/L. No serious adverse event was recorded and the highest 25(OH)D level reached, 125.0?nmol/L, is well below toxic levels. BALP and TRACP5b did not change significantly over the study period.

Conclusions

This trial suggests that a daily supplementation with 40?μg vitamin D₃ is sufficient to secure a 25(OH)D level of 50?nmol/L. No side effects were observed in the study group.     

Dietary vitamin D intake is not associated with 25-hydroxyvitamin D3 or parathyroid hormone in elderly subjects,whereas the calcium-to-phosphate ratio affects parathyroid hormone

This cross-sectional study investigates whether serum 25-hydroxyvitamin D₃ [25(OH)D₃] and intact parathyroid hormone (iPTH) are affected by vitamin D, calcium, or phosphate intake in 140 independently living elderly subjects from Germany (99 women and 41 men; age, 66-96 years). We hypothesized that habitual dietary intakes of vitamin D, calcium, and phosphate are not associated with 25(OH)D₃ or iPTH and that body mass index confounds these associations. Serum 25(OH)D₃ and iPTH were measured by an electrochemiluminescence immunoassay. Dietary intake was determined using a 3-day estimated dietary record. The median dietary intake levels of vitamin D, calcium, and phosphate were 3 μg/d, 999 mg/d, and 1250 mg/d, respectively. Multiple regression analyses confirmed that dietary vitamin D and calcium did not affect 25(OH)D₃ or iPTH; however, supplemental intakes of vitamin D and calcium were associated with 25(OH)D₃ after adjustment for age, sex, body composition, sun exposure, physical activity, and smoking. In addition, phosphate intake and the calcium-to-phosphate ratio were associated with iPTH after multiple adjustments. In a subgroup analysis, calcium and vitamin D supplements, as well as phosphate intake, were associated with 25(OH)D₃ and/or iPTH in normal-weight subjects only. Our results indicate that habitual dietary vitamin D and calcium intakes have no independent effects on 25(OH)D₃ or iPTH in elderly subjects without vitamin D deficiency, whereas phosphate intake and the calcium-to-phosphate ratio affect iPTH. However, vitamin D and calcium supplements may increase 25(OH)D₃ and decrease iPTH, even during the summer, but the impact of supplements may depend on body mass index.     

Vitamin D status indicators in indigenous populations in East Africa

Purpose

Sufficient vitamin D status may be defined as the evolutionary established circulating 25-hydroxyvitamin D [25(OH)D] matching our Paleolithic genome.

Methods

We studied serum 25(OH)D [defined as 25(OH)D₂ + 25(OH)D₃] and its determinants in 5 East African ethnical groups across the life cycle: Maasai (MA) and Hadzabe (HA) with traditional life styles and low fish intakes, and people from Same (SA; intermediate fish), Sengerema (SE; high fish), and Ukerewe (UK; high fish). Samples derived from non-pregnant adults (MA, HA, SE), pregnant women (MA, SA, SE), mother–infant couples at delivery (UK), infants at delivery and their lactating mothers at 3 days (MA, SA, SE), and lactating mothers at 3 months postpartum (SA, SE). Erythrocyte docosahexaenoic acid (RBC-DHA) was determined as a proxy for fish intake.

Results

The mean ± SD 25(OH)D of non-pregnant adults and cord serum were 106.8 ± 28.4 and 79.9 ± 26.4 nmol/L, respectively. Pregnancy, delivery, ethnicity (which we used as a proxy for sunlight exposure), RBC-DHA, and age were the determinants of 25(OH)D. 25(OH)D increased slightly with age. RBC-DHA was positively related to 25(OH)D, notably 25(OH)D₂. Pregnant MA (147.7 vs. 118.3) and SE (141.9 vs. 89.0) had higher 25(OH)D than non-pregnant counterparts (MA, SE). Infant 25(OH)D at delivery in Ukerewe was about 65 % of maternal 25(OH)D.

Conclusions

Our ancient 25(OH)D amounted to about 115 nmol/L and sunlight exposure, rather than fish intake, was the principal determinant. The fetoplacental unit was exposed to high 25(OH)D, possibly by maternal vitamin D mobilization from adipose tissue, reduced insulin sensitivity, trapping by vitamin D-binding protein, diminished deactivation, or some combination.     

Vitamin D status among older community dwelling men living in a sunny country and associations with lifestyle factors: The concord health and ageing in men project, Sydney, Australia

Objectives

Inadequate vitamin D status (25-hydroxyvitamin D (25(OH)D) concentrations <50 nmol/L) is an increasingly important public health issue in Australia. The aim of this analysis is to describe 25(OH)D levels in community dwelling men aged ≥70 years in Sydney, Australia, and to determine associations between serum 25(OH)D levels and socioeconomic and lifestyle factors.

Design

A population-based, crosssectional analysis of the baseline phase of the Concord Health and Ageing in Men Project (CHAMP), a large epidemiological study conducted in Sydney between January 2005 and May 2007.

Participants

1659 noninstitutionalised men aged ≥70 years.

Methods

The cross-sectional analysis of the baseline phase of the Concord Health and Ageing in Men Project (CHAMP), a large epidemiological study conducted in Sydney between January 2005 and May 2007. Participants included 1659 community dwelling men who were interviewed and had clinical assessments. Main outcome measurements included serum 25(OH)D levels measured in blood samples using a radioimmunoassay kit (DiaSorin Inc., Stillwater, MN). Covariates included age, socioeconomic measures, season of blood sample, physical activity, sun exposure, vitamin D supplement use, cigarette smoking status, alcohol consumption, obesity and measures of health.

Results

Prevalence of vitamin D insufficiency was 43.0%; highest in winter (55.5%) and spring (53.9%), and was associated with season (winter and spring), low physical activity, avoidance of sun exposure, current smoking and obesity, even after adjustment for confounding factors.

Conclusion

Inadequate vitamin D status is highly prevalent among Australian older men and is associated with specific lifestyle factors. These findings emphasize the need to screen and monitor 25(OH)D levels in this population group, despite living in a sunny country such as Australia.     

A prospective study of plasma vitamin D metabolites, vitamin D receptor gene polymorphisms, and risk of hypertension in men

Purpose

Laboratory studies have suggested that vitamin D inadequacy may be implicated in development of hypertension. Evidence from epidemiologic studies remains limited. We aim to examine the prospective associations of circulating vitamin D metabolites, vitamin D receptor (VDR) gene polymorphisms, and their interaction with risk of hypertension.

Methods

We conducted prospective analyses among 1,211 US men that were free of baseline hypertension and had baseline plasma 25hydroxy-vitamin D (25(OH)D) or 1,25dihydroxy-vitamin D (1,25(OH)₂D) measured and VDR BsmI or FokI polymorphisms genotyped.

Results

During 15.3-year follow-up, 695 men developed incident hypertension. After multivariable adjustment, the hazard ratios (HRs) and 95 % CIs for hypertension across increasing quartiles of plasma vitamin D metabolites were 1.00 (ref), 0.94 (0.69–1.27), 0.69 (0.50–0.96), and 0.82 (0.60–1.13) for 25(OH)D (p, trend: 0.43), and 1.00, 0.92 (0.66–1.27), 1.12 (0.82–1.54), and 1.19 (0.86–1.63) for 1,25(OH)₂D (p, trend: 0.16). Compared with carriers of VDR BsmI bb, carriers of bB or BB had a HR of 1.25 (1.04–1.51) for hypertension. For VDR FokI polymorphism, compared with carriers of FF and Ff combined, carriers of ff had a HR of 1.32 (1.03–1.70). The relation between plasma 25(OH)D and risk of hypertension did not differ by VDR BsmI and FokI polymorphisms.

Conclusions

In a prospective cohort of men, we found suggestive evidence for an inverse association between plasma 25(OH)D and risk of hypertension. We also found associations between VDR BsmI and FokI polymorphisms with hypertension risk. More research is needed to further determine the role of vitamin D in hypertension prevention.     

Vitamin D supplementation,body weight and human serum 25-hydroxyvitamin D response: a systematic review

Purpose

There is considerable variation in incremental circulating 25-hydroxyvitamin D (25OHD) levels on vitamin D supplements, even when similar age groups and identical vitamin D doses are compared. We therefore aimed to investigate the importance of body weight for the dose–response relation in circulating 25OHD.

Methods

We performed a systematic review of randomized placebo-controlled vitamin D supplementation trials in all age groups ≥10 years to clarify the influence of body weight and other parameters on incremental circulating 25OHD levels (difference between baseline and in-study values) in vitamin D-deficient and non-deficient individuals.

Results

We included 144 cohorts from 94 independent studies, published from 1990 to November 2012, in our systematic review. There was a logarithmic association between vitamin D dose per kg body weight per day and increment in circulating 25OHD. In multivariable regression analysis, vitamin D dose per kg body weight per day could explain 34.5 % of variation in circulating 25OHD. Additional significant predictors were type of supplement (vitamin D₂ or vitamin D₃), age, concomitant intake of calcium supplements and baseline 25OHD, explaining 9.8, 3.7, 2.4 and 1.9 %, respectively, of the variation in circulating 25OHD.

Conclusions

This systematic review demonstrates that body weight is an important predictor of variation in circulating 25OHD in cohorts on vitamin D supplements. Our model provides an estimate of the daily vitamin D dose that is necessary for achieving adequate circulating 25OHD levels in vitamin D-insufficient or vitamin D-deficient individuals/cohorts with different body weights and ages.     

Suboptimal maternal vitamin D status and low education level as determinants of small-for-gestational-age birth weight

Purpose

This study aimed firstly to investigate the contribution of maternal 25(OH) vitamin D to the association of maternal education and small-for-gestational-age birth weight (SGA) and secondly to examine whether the contribution of 25(OH) vitamin D differs by overweight, season, and maternal smoking.

Methods

Logistic regression analysis was carried out in this study, using data of 2,274 pregnant women of Dutch ethnicity from the ABCD study, a population-based cohort study in the Netherlands. Maternal 25(OH) vitamin D was measured in early pregnancy. Stratified analyses were conducted for overweight, season of blood sampling, and smoking.

Results

Low-educated women had lower 25(OH) vitamin D levels compared to high-educated women, and women in the lowest 25(OH) vitamin D quartile had a higher risk of SGA offspring. In addition, low-educated women had a higher risk of SGA offspring (OR 1.95 [95% CI: 1.20–3.14]). This association decreased with 7% after adjustment for 25(OH) vitamin D (OR 1.88 [95% CI 1.16–3.04]). In stratified analyses, adjustment for 25(OH) vitamin D resulted in a decrease in OR of about 17% in overweight women and about 15% in women who conceived in wintertime.

Conclusions

25(OH) vitamin D appears to be a modifiable contributor to the association between low maternal education and SGA offspring, particularly in overweight women and women who conceived in the winter period. In those women, increasing the intake of vitamin D, either through dietary adaptation or through supplementation in order to achieve the recommendation, could be beneficial.     

Prevalence of hypovitaminosis D and folate deficiency in healthy young female Austrian students in a health care profession

Purpose

We performed a single-day cross-sectional study to assess the prevalence of vitamin D deficiency as well as folate status in healthy young female volunteers well educated with respect to health information.

Methods

We assessed dietary intake of vitamin D and calcium, serum concentrations of 25-OH-vitamin D₃, folate, red blood cell folate and other dietary, laboratory, and lifestyle parameters in 215 young healthy women (age 18–30?years) on a single day at the end of the winter months. Primary aim was to investigate the prevalence of hypovitaminosis D. Folic acid status was a secondary study aim.

Results

Mean daily ingestion of vitamin D was 2.25?μg/day with a daily calcium intake of 749?mg/day. 6.9% had hypovitaminosis D (25-OH-vitamin D₃ <30?nmol/L) and 89.3% were vitamin D insufficient (<75?nmol/L). Preplanned subpopulation comparison (lower vs. upper quartile) revealed a significant negative correlation (P?=?0.048) between plasma PTH and 25-OH-vitamin D₃ levels. Fifteen individuals (6.9%) were folic acid deficient (<140?ng/mL RBC folate). Only 9.3% reached RBC folate concentrations regarded as optimal for the prevention of fetal neural tube defects (>400?ng/mL).

Conclusions

The prevalence of hypovitaminosis D in healthy young women trained in health care professions is low but 89.3% can be classified as vitamin D insufficient in spring. Folate status can also be considered not sufficient. Considering the emerging role of higher vitamin D plasma levels for many health conditions, a timely correction of vitamin D status in the general Austrian population appears appropriate.     

Hypovitaminosis D in psychogeriatric inpatients

Objectives

This study investigated the rate of hypovitaminosis D in psychogeriatric inpatients and explored whether any associations exist between vitamin D levels, cognitive function, and psychiatric diagnoses.

Design

Retrospective medical record review from November 2000 through November 2010.

Setting

Geriatric psychiatric ward of an academic tertiary care hospital.

Participants

Psychiatric inpatients aged 65 years or older.

Measurements and analysis methods

Serum 25-hydroxyvitamin D [25(OH)D] levels were measured at admission. Associations between 25(OH)D levels, Mini-Mental State Examination (MMSE) scores were analyzed using Spearman correlations, and psychiatric diagnoses were analyzed using logistic regression models and Fisher’s exact tests.

Results

In 141 subjects (mean age, 77. In 141 subjects (mean age, 77.8 years; 86 [61%] female; 135 [96%] white), the most frequent diagnoses were major depressive disorder in 81 patients (57%), dementia in 38 (27%), delirium in 13 (9%), anxiety in 12 (8.5%), and bipolar disorder in 11 (8%). Mean MMSE score was 24±6.4 (range, 3–30). Forty-three subjects (30.4%) had mild to moderate vitamin D deficiency [25(OH)D, 10–24 ng/mL], and 6 (4.2%) had severe deficiency [25(OH)D <10 ng/mL].

Conclusions

Hypovitaminosis D was common in elderly psychiatric inpatients. No associations were found between vitamin D levels and global cognitive function or psychiatric diagnoses.     

Different doses of supplemental vitamin D maintain interleukin-5 without altering skeletal muscle strength: a randomized, double-blind, placebo-controlled study in vitamin D sufficient adults

Background

Supplemental vitamin D modulates inflammatory cytokines and skeletal muscle function, but results are inconsistent. It is unknown if these inconsistencies are dependent on the supplemental dose of vitamin D. Therefore, the purpose of this study was to identify the influence of different doses of supplemental vitamin D on inflammatory cytokines and muscular strength in young adults.

Methods

Men (n = 15) and women (n = 15) received a daily placebo or vitamin D supplement (200 or 4000 IU) for 28-d during the winter. Serum 25-hydroxyvitamin D (25(OH)D), cytokine concentrations and muscular (leg) strength measurements were performed prior to and during supplementation. Statistical significance of data were assessed with a two-way (time, treatment) analysis of variance (ANOVA) with repeated measures, followed by a Tukey's Honestly Significant Difference to test multiple pairwise comparisons.

Results

Upon enrollment, 63% of the subjects were vitamin D sufficient (serum 25(OH)D ?? 30 ng/ml). Serum 25(OH)D and interleukin (IL)-5 decreased (P < 0.05) across time in the placebo group. Supplemental vitamin D at 200 IU maintained serum 25(OH)D concentrations and increased IL-5 (P < 0.05). Supplemental vitamin D at 4000 IU increased (P < 0.05) serum 25(OH)D without altering IL-5 concentrations. Although serum 25(OH)D concentrations correlated (P < 0.05) with muscle strength, muscle strength was not changed by supplemental vitamin D.

Conclusion

In young adults who were vitamin D sufficient prior to supplementation, we conclude that a low-daily dose of supplemental vitamin D prevents serum 25(OH)D and IL-5 concentration decreases, and that muscular strength does not parallel the 25(OH)D increase induced by a high-daily dose of supplemental vitamin D. Considering that IL-5 protects against viruses and bacterial infections, these findings could have a broad physiological importance regarding the ability of vitamin D sufficiency to mediate the immune systems protection against infection.     

New perspectives on vitamin D sources in Germany based on a novel mathematical bottom-up model of 25(OH)D serum concentrations

Purpose

Up-to-date knowledge about vitamin D supply and serum concentration in Germany is not sufficient. Our purpose was to compare a novel holistic bottom-up modeling of 25(OH)D concentrations with vitamin D sources such as sunlight, food and supplements for all federal states taking seasonal and geographical variations into account. The second purpose was to update and detail vitamin D supply through food in Germany.

Methods

To confirm the model of 25(OH)D concentrations, we used the population (1,763 men and 2,267 women, 18–79 years) participated in the representative German National Health Interview and Examination Survey 1998 and the integrated German Nutrition Survey.

Results

The maximum model value is 67.5 nmol/L in July and minimum model value is 29.3 nmol/L in January, while the average model value is 45.0 nmol/L. Men have a mean daily intake of 137 IU (3.42 μg) and women of 112 IU (2.79 μg). Correlation between model and actual data is 0.77 (p = 0.003).

Conclusions

A comparison of the model data with population-based values showed good agreement. None of the vitamin D sources can provide the German population with enough vitamin D.     

Evaluation of cognitive subdomains, 25-hydroxyvitamin D,and 1,25-dihydroxyvitamin D in the European Male Ageing Study

Purpose

Although lower levels of vitamin D have been related to poor cognitive functioning and dementia in older adults, evidence from longitudinal investigations is inconsistent. The objective of this study was to determine whether 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)₂D] levels are associated with specified measures of cognitive decline in ageing men.

Methods

The European Male Ageing Study (EMAS) followed 3369 men aged 40–79 over 4.4 years. 25(OH)D levels at baseline were measured by radioimmunoassay, and 1,25(OH)₂D levels were obtained with liquid chromatography–tandem mass spectrometry. Visuoconstructional abilities, visual memory, and processing speed at baseline and follow-up were assessed using the Rey–Osterrieth Complex Figure Test (ROCF), Camden Topographical Recognition Memory (CTRM), and the Digit Symbol Substitution Test (DSST).

Results

Following attritions, a total of 2430 men with a mean (SD) age of 59.0 (10.6) were included in the analyses. At baseline, the mean 25(OH)D concentration was 64.6 (31.5) nmol/l, and mean 1,25(OH)₂D level was 59.6 (16.6) pmol/l. In age-adjusted linear regression models, high 25(OH)D concentrations were associated with a smaller decline in the DSST (β = 0.007, p = 0.020). Men with low 25(OH)D levels (<50 nmol/l) showed a greater decline in the CTRM compared to men with higher (≥75 nmol/l) levels (β = ?0.41, p = 0.035). However, these associations disappeared after adjusting for confounders such as depressive symptoms, BMI, and comorbidities. There was no indication of a relationship between 1,25(OH)₂D and decline in cognitive subdomains.

Conclusion

We found no evidence for an independent association between 25(OH)D or 1,25(OH)₂D levels and visuoconstructional abilities, visual memory, or processing speed over on average 4.4 years in this sample of middle-aged and elderly European men.

     

Plasma vitamin D biomarkers and leukocyte telomere length in men

Purpose

Vitamin D may reduce telomere shortening through anti-inflammatory and anti-cell proliferation mechanisms. In women, higher plasma 25-hydroxyvitamin D (25(OH)D) has been shown to be associated with longer telomere length, but the relationship has not been assessed in men.

Methods

We conducted a cross-sectional analysis of 25(OH)D, 1,25-dihydroxyvitamin D (1,25(OH)₂D) and relative leukocyte telomere length (LTL) among 2483 men [1832 men for 1,25(OH)₂D] who were selected as cases and controls in three studies of telomeres and cancer nested within the Health Professionals Follow-up Study. We also genotyped 95 SNPs representing common genetic variation in vitamin D pathway genes. LTL was measured by quantitative PCR, and z-scores within each study were calculated. Associations were assessed by linear as well as logistic regression adjusting for age and other potential confounders.

Results

Age (P-trend < 0.0001), pack-years of smoking (P-trend = 0.04) and body mass index (P-trend = 0.05) were inversely associated with LTL. Neither 25(OH)D nor 1,25(OH)₂D was associated with LTL (multivariable-adjusted P-trend 0.69 and 0.41, respectively, for the linear regression model). One SNP in the retinoid X receptor alpha gene was associated with long LTL (P = 0.0003).

Conclusions

In this cross-sectional study of men, 25(OH)D and 1,25(OH)₂D were not associated with relative LTL.

     

Cross-sectional and longitudinal relation between serum 25-hydroxyvitamin D and body mass index: the Tromsø study

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.     

Vitamin D and health-related quality of life in a community sample of older Canadians

Purpose

To assess how vitamin D status is associated with health-related quality of life (HRQOL) among older residents of Canada.

Design

We analysed baseline data of 1,493 Canadians aged 50 years and over in Alberta on HRQOL (EQ-5D-5L) and serum 25-hydroxyvitamin D (25(OH)D) as a measure of vitamin D status. We applied multivariable regression methods to examine the association between vitamin D status and each of the five dimensions and the summary index of the EQ-5D-5L.

Results

Participants with higher serum 25(OH)D levels were significantly less likely to report problems with mobility, usual activities, and depression and anxiety. Specifically, age- and gender-adjusted odds ratios for reporting problems with mobility, usual activities, and depression and anxiety were 0.58 (95 % confidence interval 0.44–0.78), 0.67 (0.50–0.89), and 0.67 (0.51–0.88) per 100 nmol/L increase in 25(OH)D, respectively. No significant associations were observed for problems with self-care and with pain and discomfort. HRQOL scores combining the responses of each of the five dimensions increased significantly with increasing serum 25(OH)D levels.

Conclusions

This is the first study to reveal the importance of vitamin D for the five dimensions of HRQOL in a community-based sample. The observed associations of vitamin D and HRQOL call for intervention studies to strengthen the evidence of the potential benefits of vitamin D supplementation for HRQOL among older adults.     

Effects of a healthy Nordic diet on plasma 25-hydroxyvitamin D concentration in subjects with metabolic syndrome: a randomized,placebo-controlled trial (SYSDIET)

Purpose

At northern latitudes, vitamin D is not synthesized endogenously during winter, causing low plasma 25-hydroxyvitamin D (25(OH)D) concentrations. Therefore, we evaluated the effects of a healthy Nordic diet based on Nordic nutrition recommendations (NNR) on plasma 25(OH)D and explored its dietary predictors.

Methods

In a Nordic multi-centre trial, subjects (n = 213) with metabolic syndrome were randomized to a control or a healthy Nordic diet favouring fish (≥300 g/week, including ≥200 g/week fatty fish), whole-grain products, berries, fruits, vegetables, rapeseed oil and low-fat dairy products. Plasma 25(OH)D and parathyroid hormone were analysed before and after 18- to 24-week intervention.

Results

At baseline, 45 % had vitamin D inadequacy (<50 nmol/l), whereas 8 % had deficiency (<25 nmol/l). Dietary vitamin D intake was increased by the healthy Nordic diet (P < 0.001). The healthy Nordic and the control diet reduced the prevalence of vitamin D inadequacy by 42 % (P < 0.001) and 19 % (P = 0.002), respectively, without between-group difference (P = 0.142). Compared with control, plasma 25(OH)D (P = 0.208) and parathyroid hormone (P = 0.207) were not altered by the healthy Nordic diet. Predictors for 25(OH)D were intake of vitamin D, eicosapentaenoic acids (EPA), docosahexaenoic acids (DHA), vitamin D supplement, plasma EPA and plasma DHA. Nevertheless, only vitamin D intake and season predicted the 25(OH)D changes.

Conclusion

Consuming a healthy Nordic diet based on NNR increased vitamin D intake but not plasma 25(OH)D concentration. The reason why fish consumption did not improve vitamin D status might be that many fish are farmed and might contain little vitamin D or that frying fish may result in vitamin D extraction. Additional ways to improve vitamin D status in Nordic countries may be needed.     

Dietary,lifestyle, and genetic determinants of vitamin D status: a cross-sectional analysis from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Germany study

Purpose

Considerable variation in 25-hydroxyvitamin D (25(OH)D) in populations worldwide that seems to be independent of latitude has been reported. Therefore, we aimed to assess vitamin D status of a mid-aged German general population and to identify its dietary, lifestyle, anthropometric, and genetic determinants.

Methods

25(OH)D concentrations were measured by LC–MS/MS in plasma samples of a random subcohort of the German arm of the European Prospective Investigation into Cancer and Nutrition (EPIC) comprising 2,100 subjects aged 35–65 years. Associations between potential predictors and 25(OH)D were assessed by linear regression models.

Results

32.8 % of the variance in 25(OH)D was explained by a multivariable regression model, with season being the by far strongest predictor (semi-partial R ²: 14.6 %). Sex, waist circumference, leisure time physical activity, smoking, polymorphisms in the GC, CYP2R1, and DHCR7 genes, supplement use, exogenous hormone use, alcohol consumption, egg consumption, and fish consumption were significantly associated with 25(OH)D concentrations as well. However, none of these factors explained >2.3 % of the variance in 25(OH)D.

Conclusion

Even with a comprehensive set of genetic, anthropometric, dietary, and lifestyle correlates, not more than 32.8 % of the variation in 25(OH)D could be explained in the EPIC-Germany study, implying that vitamin D prediction scores may not provide an appropriate proxy for measured 25(OH)D. Food intake was only a weak predictor of 25(OH)D concentrations, while a strong seasonal fluctuation in 25(OH)D was shown.     

The use of dietary supplements among older persons in Southern Germany — Results from the KORA-age study

Objectives

Current population-based surveys in Europe on the prevalence of dietary supplement (DS) use in older individuals are scarce. The aim of the present study was to investigate patterns, prevalence and determinants of non-herbal DS use in aged subjects. Furthermore, the intake amounts of vitamins and minerals from supplements were assessed.

Design

Cross-sectional.

Setting

Data on supplement use were available from an age- and sex-stratified random sample of the German population-based KORA (Cooperative Health Research in the Region of Augsburg)-Age study.

Participants

1,079 persons who were born in or before the year 1943.

Measurements

Use of dietary supplements and medications during the last seven days was recorded in a face-to-face interview in 2009. Participants were asked to bring all packages of ingested preparations to the study center. Not only vitamin/mineral supplements, but also non-vitamin non-mineral non-herbal supplements and drugs containing vitamins and minerals were coded as DS.

Results

The age-standardized prevalence of DS intake was 54.3% in women and 33.8% in men, respectively. The most commonly supplemented mineral and vitamin, respectively, was magnesium (31.9%) and vitamin D (21.5%) in women and magnesium (18.0%) and vitamin E (12.0%) in men. The highest intakes, compared to the German Dietary Reference Intakes, were reported for biotin, vitamin B₆ and B₁. Excessive intakes (equal or above the European Tolerable Upper Intake Levels (UL)) were observed especially for magnesium and vitamin E. 20.2% of the women and 32.5% of the men who took magnesium supplements regularly exceeded the UL for magnesium. In case of vitamin E this was true for 8.0% of the women and 13.6% of the men. Determinants of DS use were sex, education, smoking, physical activity, neurological diseases, and stroke.

Conclusion

A high proportion of the general population aged 65 years and older in Southern Germany uses DS, especially supplements containing vitamins/minerals. The supplementation of vitamin D can be regarded as favorable in this age group, whereas the excessive intakes of vitamin E might be a cause of concern.     

Associations of 25-hydroxyvitamin D with fasting glucose, fasting insulin, dementia and depression in European elderly: the SENECA study

Purpose

The classical consequence of vitamin D deficiency is osteomalacia, but recent insights into the function of vitamin D suggest that it may play a role in other body systems as well. The objective of this study was to examine the association between 25-hydroxyvitamin D (25(OH)D) and markers of glucose metabolism (n = 593), global cognitive functioning (n = 116) and depression (n = 118) in European elderly participating in the SENECA study. Moreover, we wanted to explore whether the observed associations of 25(OH)D with depression and global cognitive performance were mediated by fasting plasma glucose (FPG) levels.

Methods

Cross-sectional associations between 25(OH)D and FPG, fasting plasma insulin (FPI) and homeostatic model assessment-insulin resistance (HOMA-IR), a marker of insulin resistance, were estimated from multiple regression analyses. Associations of 25(OH)D with global cognitive functioning (Mini Mental State Examination) and depression (Geriatric Depression Scale) were examined using Poisson regression.

Results

An inverse association was observed between 25(OH)D and FPG (β-0.001), indicating a 1 % decrease in FPG per 10 nmol/L increase in 25(OH)D, but after full adjustment for demographic factors, lifestyle factors and calcium intake, this association was not statistically significant (P = 0.07). Although participants with intermediate and high serum 25(OH)D levels showed a tendency towards a lower depression score after adjustment for demographic and lifestyle factors, RR and 95 % CI: 0.73 (0.51–1.04) and 0.76 (0.52–1.11), respectively, these findings were not statistically significant.

Conclusion

An inverse association of 25(OH)D with depression and FPG was observed, but this association was not statistically significant. There was no association between 25(OH)D with FPI and HOMA-IR or with global cognitive functioning. More studies are needed to further explore the possible role of vitamin D in the various body systems.