Vitamin D levels in an Australian population

Oxidative Stress in Military Missions-Impact and Management Strategies: A Narrative Analysis

This narrative review comprehensively examines the impact of oxidative stress on military personnel, highlighting the crucial role of physical exercise and tailored diets, particularly the ketogenic diet, in minimizing this stress. Through a meticulous analysis of the recent literature, the study emphasizes how regular physical exercise not only enhances cardiovascular, cognitive, and musculoskeletal health but is also essential in neutralizing the effects of oxidative stress, thereby improving endurance and performance during long-term missions. Furthermore, the implementation of the ketogenic diet provides an efficient and consistent energy source through ketone bodies, tailored to the specific energy requirements of military activities, and significantly contributes to the reduction in reactive oxygen species production, thus protecting against cellular deterioration under extreme stress. The study also underlines the importance of integrating advanced technologies, such as wearable devices and smart sensors that allow for the precise and real-time monitoring of oxidative stress and physiological responses, thus facilitating the customization of training and nutritional regimes. Observations from this review emphasize significant variability among individuals in responses to oxidative stress, highlighting the need for a personalized approach in formulating intervention strategies. It is crucial to develop and implement well-monitored, personalized supplementation protocols to ensure that each member of the military personnel receives a regimen tailored to their specific needs, thereby maximizing the effectiveness of measures to combat oxidative stress. This analysis makes a valuable contribution to the specialized literature, proposing a detailed framework for addressing oxidative stress in the armed forces and opening new directions for future research with the aim of optimizing clinical practices and improving the health and performance of military personnel under stress and specific challenges of the military field.

Serum 25-Hydroxyvitamin D and Risk of Disability in Activities of Daily Living among the Oldest-Old: An Observational and Mendelian Randomization Study

BACKGROUND

Vitamin D deficiency and disability are both prevalent among older adults. However, the association between them has rarely been investigated in the oldest-old subjects (aged ≥80 y), and the causality remains unclear.

OBJECTIVE

This study aimed to elucidate the causal effect of vitamin D on the incident risk of disability in activities of daily living (ADL) among Chinese oldest-old based on the 2012-2018 Chinese Healthy Ageing and Biomarkers Cohort Study.

METHODS

Serum 25-hydroxyvitamin D [25(OH)D] concentrations and ADL status at baseline and follow-up interviews were documented. Cox regression models were applied among 1427 oldest-old (mean age, 91.2 y) with normal baseline ADL status. One sample Mendelian randomization (MR) analyses were performed on a subset of 941 participants with qualified genetic data, using a 25(OH)D-associated genetic risk score as the genetic instrument.

RESULTS

During a median follow-up of 3.4 y, 231 participants developed disability in ADL. Serum 25(OH)D concentration was inversely associated with the risk of disability in ADL [per 10 nmol/L increase hazard ratio (HR) 0.85; 95% CI: 0.75, 0.96]. Consistent results from MR analyses showed that a 10 nmol/L increment in genetically predicted 25(OH)D concentration corresponded to a 20% reduced risk of ADL disability (HR 0.80; 95% CI: 0.68, 0.94). Nonlinear MR demonstrated a monotonic declining curve, with the HRs exhibiting a more pronounced reduction among individuals with 25(OH)D concentrations below 50 nmol/L. Subgroup analyses showed that the associations were more distinct among females and those with poorer health conditions.

CONCLUSIONS

Our study supports an inverse causal relationship between serum 25(OH)D concentration and the risk of disability in ADL among Chinese oldest-old. This protective effect was more distinct, especially for participants with vitamin D deficiency. Appropriate measures for improving vitamin D might help reduce the incidence of physical disability in this specific age group.

A preliminary investigation of the clinical and cognitive correlates of circulating vitamin D in bipolar disorder

The role that vitamin D plays in the cognitive and clinical characteristics of bipolar disorder (BD) is unclear. We examined differences in the levels and deficiency status of vitamin D in an Australian sample of BD patients compared to healthy controls; and determined the extent to which vitamin D is associated with clinical variables and cognitive function in the sample. 22 healthy controls and 55 stable outpatients with a diagnosis of BD and low-grade mood symptomatology provided a sample of blood and completed cognitive tests and clinical measures. Plasma concentrations of 25-hydroxyvitamin D (vitamin D) were assayed and used to segregate participants into subgroups with sufficient or deficient levels of vitamin D. Subgroups were then compared in terms of global cognition and a range of sociodemographic and clinical factors (number of past mood episodes, illness duration, seasonal mood pattern, mood symptom severity), while mean levels of vitamin D were compared between patients and controls. Although almost 27% of the current sample were vitamin D deficient, no significant differences in mean vitamin D levels or the prevalence of vitamin D deficiency were evident between BD patients and controls. Vitamin D was not associated with global cognition in either patients or controls, nor any of the clinical measures assessed in the study. In conclusion, we observed no difference in the vitamin D levels and deficiency status of an Australian sample of healthy individuals and BD patients with low grade mood symptomatology compared to controls. Clinical symptoms and global cognition also appear to be independent of vitamin D levels in BD.

Maternal plasma vitamin D levels across pregnancy are not associated with neonatal birthweight: findings from an Australian cohort study of low-risk pregnant women

BACKGROUND

In utero environments can be highly influential in contributing to the development of offspring obesity. Specifically, vitamin D deficiency during pregnancy is associated with adverse maternal and child health outcomes, however its relationship with offspring obesity remains unclear. We assessed maternal vitamin D status across pregnancy, change in plasma vitamin D concentrations and associations with neonatal birthweight, macrosomia and large for gestational age.

METHODS

Women (n = 221) aged 18-40 years with singleton (low-risk) pregnancies, attending antenatal clinics at a tertiary-level maternity hospital were recruited at 10-20 weeks gestation. Medical history, maternal weight and blood samples at three antenatal clinic visits were assessed; early (15 ± 3 weeks), mid (27 ± 2 weeks) and late (36 ± 1 weeks) gestation. Maternal 25(OH)D was analysed from stored plasma samples via liquid chromatography-tandem mass spectrometry (LC/MS/MS). Neonatal growth parameters were collected at birth. Unadjusted and adjusted linear and logistic regression assessed associations of maternal vitamin D with birthweight, macrosomia and large for gestational age.

RESULTS

Mean plasma 25(OH)D increased from early (83.8 ± 22.6 nmol/L) to mid (96.5 ± 28.9 nmol/L) and late (100.8 ± 30.8 nmol/L) gestation. Overall 98% of women were taking vitamin D-containing supplements throughout their pregnancy. Prevalence of vitamin D deficiency (25(OH)D < 50 nmol/L) was 6.5%, 6.3% and 6.8% at early, mid and late pregnancy respectively. No statistically significant association was found between 25(OH)D or vitamin D deficiency at any timepoint with neonatal birthweight, macrosomia or large for gestational age.

CONCLUSIONS

Prevalence of vitamin D deficiency was low in this cohort of pregnant women and likely related to the high proportion of women taking vitamin D supplements during pregnancy. Maternal 25(OH)D did not impact offspring birth weight or birth size. Future studies in high-risk pregnant populations are needed to further assess maternal vitamin D status and factors in utero which promote early life obesity.

Serum 25-Hydroxyvitamin D Levels in Type 2 Diabetes Patients in North China: Seasonality and the Association between Vitamin D Status and Glycosylated Hemoglobin Levels

Background and Aims

Previous studies have reported a correlation between vitamin D levels and seasonality in healthy populations. However, there are few studies on the seasonal variation in vitamin D levels and its relationship with glycosylated hemoglobin (HbA1c) in patients with type 2 diabetes mellitus (T2DM). The objective of this study was to investigate seasonal changes in serum 25-hydroxyvitamin D [25(OH)D] levels and the associations between these vitamin D concentrations and HbA1c levels in T2DM patients in Hebei, China.

Methods

A cross-sectional study of 1,074 individuals with T2DM was conducted from May 2018 to September 2021. Levels of 25(OH)D in these patients were assessed based on both sex and season, and relevant clinical or laboratory variables that could impact vitamin D status were also considered.

Results

In the T2DM patient cohort, the mean blood 25(OH)D levels were 17.05 ng/mL. A total of 698 patients (65.0%) had insufficient serum 25(OH)D levels. The vitamin D deficiency rates were significantly higher in the winter and spring compared to the autumn (P < 0.05), indicating that seasonal fluctuations can have a significant impact on 25(OH)D levels. The levels of vitamin D inadequacy were highest in the winter (74%), and females were more likely than males to be deficient (73.4% vs. 59.5%, P < 0.001). In comparison to the winter and spring, both males and females showed higher 25(OH)D levels in the summer (P < 0.001). HbA1c levels were 8.9% higher in those with vitamin D deficiencies than in nondeficient patients (P < 0.001). HbA1c and vitamin D levels were negatively correlated (r = -0.119, P < 0.001).

Conclusion

Vitamin D deficiencies are particularly prevalent among T2DM patients in Hebei, China, with exceptionally high rates in the winter and spring. Female T2DM patients were at an elevated risk of vitamin D deficiency, and vitamin D levels were negatively correlated with HbA1c.

Vitamin D and musculoskeletal health: outstanding aspects to be considered in the light of current evidence

Vitamin D enhances calcium absorption and bone mineralisation, promotes maintenance of muscle function, and is crucial for musculoskeletal health. Low vitamin D status triggers secondary hyperparathyroidism, increases bone loss, and leads to muscle weakness. The primary physiologic function of vitamin D and its metabolites is maintaining calcium homeostasis for metabolic functioning, signal transduction, and neuromuscular activity. A considerable amount of human evidence supports the well-recognised contribution of adequate serum 25-hydroxyvitamin D concentrations for bone homeostasis maintenance and prevention and treatment strategies for osteoporosis when combined with adequate calcium intake. This paper aimed to review the literature published, mainly in the last 20 years, on the effect of vitamin D and its supplementation for musculoskeletal health in order to identify the aspects that remain unclear or controversial and therefore require further investigation and debate. There is a clear need for consistent data to establish realistic and meaningful recommendations of vitamin D status that consider different population groups and locations. Moreover, there is still a lack of consensus on thresholds for vitamin D deficiency and optimal status as well as toxicity, optimal intake of vitamin D, vitamin D supplement alone as a strategy to prevent fractures and falls, recommended sun exposure at different latitudes and for different skin pigmentations, and the extra skeletal effects of vitamin D.

Factors Associated with Low Vitamin D Status among Older Adults in Kuwait

Low vitamin D levels among older people represent a significant health problem worldwide. This study aimed to examine the factors associated with vitamin D deficiency in older people (aged ≥ 65) in the Kuwaiti population. A cross-sectional study was conducted in seven primary healthcare centers across Kuwait (November 2020 to June 2021). The participants (n = 237) had their serum vitamin D (25(OH)D) concentrations (analyzed using LC-MS) classified as sufficiency 75 nmol/L (30 ng/mL) or deficiency < 75 nmol/L (below 30 ng/mL). The data were collected using self-administered questionnaires and face-to-face interviews with participants in geriatric clinics. Binomial logistic regression analysis was applied to assess factors associated with vitamin D deficiency. Vitamin D deficiency was found to be present in two thirds of the participants (n = 150, 63%), with a higher prevalence of deficiency in participants who did not receive vitamin D supplements, compared to those who did (84% vs. 16%, p = 0.001). The results from the binary logistic regression showed that a low duration of sun exposure (OR = 0.24, 95% C.I. [0.08−0.7], p = 0.011), dark skin pigmentation (OR = 4.46, 95% [1.35−20.49], p = 0.026), and lower caloric intake (OR = 0.9, 95% C.I. [0.85−0.96], p = 0.001) were risk factors for vitamin D deficiency. Furthermore, a significant inverse relationship was found between vitamin D levels and parathyroid hormone (PTH) levels (OR = 1.16, 95% C.I. [1.04−1.31], p = 0.016). These findings support the recommendation that vitamin D supplementation and adequate sunlight exposure are necessary for raising low vitamin D levels in older people in Kuwait.

Wearable ultraviolet radiation sensors for research and personal use

Skin cancers are strongly linked to personal exposure to ultraviolet (UV) radiation, yet UV exposure is also the most preventable risk factor. People are exposed to UV rays when they engage in outdoor activities, particularly exercise, which is an important health behavior. Thus, researchers and the general public have shown increasing interest in measuring UV exposure using wearable sensors during outdoor physical activity. However, minimal research exists at the intersection of UV sensors, personal exposure, adaptive behavior due to exposures, and risk of skin damage. Recent years have seen an influx of new consumer-based and research-based UV-sensing technologies with wide-ranging form factors and purposes to fill this research gap, yet a thorough review of available sensors for specific purposes does not exist. Hence, the overall goal of this state-of-the-art review is to synthesize the current academic and gray literature surrounding personal UV-sensing technologies. Peer-reviewed journal articles and "gray literature," such as working papers, manuals, and UV sensor websites, were reviewed, assessing attributes of UV wearables marketed for research use, personal use, or both. Overall, 13 wearable UV sensors are available for personal use and/or research applications. These sensors vary from electronic to photochromic, with large differences in price, data outputs, accuracy, and precision. Recommendations are provided for which sensors are most suitable for various types of research or public use. Notably, the review findings will help guide researchers in future studies assessing UV exposure during physical activity.

Study of the fluctuation of serum vitamin D concentration with time during the same day and night on a random sample of healthy adults

BACKGROUND AND AIMS

A common practice in the assessment of vitamin D is to measure its blood level in the morning after overnight fasting. The aim of this study was to measure vitamin D during different times of the day and night for a random sample of healthy individuals, to see if there are significant changes throughout the day and night.

METHODS

A cross sectional study was carried out on a total of 52 randomly selected Jordanian healthy volunteers (26 women and 26 men) aged between 18 and 45 years. Six blood samples were taken from each participant on the same study day; 7:30 AM (at fasting), 10:30 AM, 1:30 PM, 4:30 PM, 7:30 PM and at 10:30 PM. An extra 7th blood sample was taken next morning at 7:30 AM (after fasting overnight).

RESULTS

There was a significant difference (P < 0.05) between mean serum vitamin D level at 7:30 AM (19.64 ± 0.26 ng/ml) and 1:30 PM (20.60 ± 0.26 ng/ml), and 4:30 PM (20.61 ± 0.26 ng/ml), P-value 0.0096 and 0.0090, respectively. When taken into consideration the effect of exposure to the sun and the time, there was a significant difference (P ˂ 0.05) between the two groups (group 1: sun protected group, and group 2: sun exposure group) at different times on the same day and the morning of the second day (P-value = 0.0113).

CONCLUSION

The serum vitamin D concentrations vary during different times of the day, night and next morning, and that its concentration at fasting does not represent its true value.

Population Vitamin D Stores Are Increasing in Tasmania, and This Is Associated With Less BMD Loss Over 10 Years

CONTEXT

Vitamin D deficiency is a common, modifiable determinant of musculoskeletal health.

OBJECTIVE

There are limited data that examine the longitudinal change in population 25-hydroxyvitamin D (25[OH]D) and none that evaluate the long-term skeletal outcomes of longitudinal vitamin D status.

METHODS

A prospective cohort analysis was conducted of community-dwelling adults aged 50 to 80 years who had 25(OH)D assessed by radioimmunoassay and bone mineral density (BMD) by dual-energy x-ray absorptiometry at baseline (n = 1096), 2.5 (n = 870), and 10 (n = 565) years. Sun exposure was quantified by questionnaire and supplement use at clinic review. 25(OH)D less than 50 nmol/L was considered deficient. Participants were provided with their 25(OH)D results.

RESULTS

Over 10 years 25(OH)D increased (52.2 ± 17.0 to 63.5 ± 23.6 nmol/L, P < .001). Participants with baseline deficiency had larger 25(OH)D increases than baseline sufficient participants (19.2 ± 25.3 vs 1.6 ± 23.3 nmol/L, P < .001). Longitudinal change in 25(OH)D was associated with baseline summer (β = 1.46, P < .001) and winter (β = 1.29, P = .003) sun exposure, change in summer (β = 1.27, P = .002) and winter (β = 1.47, P < .001) sun exposure, and vitamin D supplement use (β = 25.0-33.0, P < .001). Persistent vitamin D sufficiency was associated with less BMD loss at the femoral neck (β = 0.020, P = .027), lumbar spine (β = 0.033, P = .003), and total hip (β = 0.023, P = .021) compared to persistent vitamin D deficiency. Achieving vitamin D sufficiency was associated with less BMD loss at the lumbar spine (β = 0.045, P < .001) compared to persistent vitamin D deficiency.

CONCLUSIONS

Population 25(OH)D concentration increased because of a combination of increased sun exposure and supplement use. Maintaining or achieving vitamin D sufficiency was associated with less BMD loss over 10 years.

Future perspectives in addressing the global issue of vitamin D deficiency

Vitamin D is a fundamentally critical nutrient that the human body requires to function properly. It plays an important role in musculoskeletal health due to its involvement in the regulation of calcium and phosphorus. Having a low level of vitamin D in the body may be detrimental for a wide range of health outcomes, including risk of osteoporotic and stress fractures, risk of CVD and some cancers, and lowering of the capability of the immune system. Vitamin D is an unusual nutrient; it is not a vitamin, in the true sense of the word but a pro-hormone. The main source of vitamin D is UV exposure, not dietary intake. Interestingly, there are two forms of vitamin D, vitamin D2 and vitamin D3, both of which are metabolised into 25-hydroxyvitamin D (25(OH)D) in the liver, the biomarker of vitamin D status. Vitamin D deficiency is a global public health problem, especially amongst older people and ethnic minority groups. The newest publication from the UK Government's Public Health England Department recommends that vitamin D intake should be 10 μg daily and this recommendation compares well (albeit lower) with other guidelines such as the Institute of Medicine recommendation of 15 μg for those aged 1-70 years and 20 μg for those 70 years or over. Few countries, however, have a specific vitamin D policy to prevent deficiency in populations. Finland leads the way, demonstrating impressive results in reducing population-level vitamin D deficiency through mandatory food fortification programmes. Collaboration between academia, government and industry, including countries from varying latitudes, is essential to identify long-term solutions to the global issue of vitamin D deficiency. This paper provides a narrative review of the evidence related to the role of vitamin D deficiency in health outcomes, outlines controversies regarding setting levels of adequacy, identifies the prevalence of vitamin D deficiency across the globe, and identifies population-level strategies adopted by countries to prevent vitamin D deficiency.

Complementary and Alternative Medicine for Threatened Miscarriage: Advantages and Risks

Threatened miscarriage is one of the most common complications causing pregnancy loss, and it affects approximately 20% of confirmed pregnancies. More and more women are seeking treatment with complementary and alternative medicine (CAM) for this common complication, and it has been reported that women have had successful pregnancies after threatened miscarriage when being treated with CAM, which mainly includes Chinese herbal medicines, acupuncture, and nutritional supplements as well as psychological interventions and other approaches. However, many experts are concerned about the safety and adverse events of certain CAM approaches in women with threatened miscarriage. Therefore, this review focuses on the status of CAM for threatened miscarriage and presents the potential therapeutic efficacy and safety of CAM based on some clinical and experimental studies. We thus hope to provide some instructive suggestions for the application of CAM for treating threatened miscarriage in the future.

Prediction models and questionnaires developed to predict vitamin D status in adults: a systematic review

A systematic review of prediction models/questionnaires developed to identify people with deficient/insufficient vitamin D status shows the potential of self-reported information to estimate vitamin D status. The objective is to identify and compare existing screening tools, developed to identify vitamin D deficiency or insufficiency in adults. A systematic search of literature was conducted using MEDLINE, Scopus, Web of Science and CINAHL databases. Risk of bias and applicability concerns were assessed by quality assessment of diagnostic accuracy studies (QUADAS-2). Data were extracted on socio-demographic, anthropometric, risk factors, serum 25 hydroxyvitamin D [25(OH)D] levels, statistical methods and predictive ability. A total of 12 studies were considered for inclusion for this systematic review after screening of 4851 abstracts and 15 full-text articles. Ten of twelve studies developed prediction models and 2 studies developed questionnaires. The majority of studies had low risk of bias and applicability as assessed by QUADAS-2. All studies included only self-reported predictors of vitamin D status in their final models and development of scores. Sunlight exposure and related factors were important significant contributors to the predictive ability of the models and/or questionnaires. Sensitivity and specificity of the prediction models or questionnaires ranged from 55 to 91% and 35 to 84%, respectively. Six out of twelve studies converted final models to scores associated with vitamin D status. There was no evidence that any of these existing tools have been translated into clinical practice. The prediction models or questionnaires identified in this systematic review were moderately sensitive and specific for identifying people with vitamin D deficiency or insufficiency. The substantial contribution of sunlight exposure to the prediction of vitamin D status highlights the importance of including this information when developing vitamin D screening tools.

Are Adequate Vitamin D Levels Helpful in Fighting COVID-19? A Look at the Evidence

COVID-19 is a global pandemic with high mortality in vulnerable groups. Given the current lack of definitive treatment or vaccine that significantly reduces mortality rate, governments, researchers and healthcare providers are racing to find possible solutions to the crisis. Vitamin D and its analogues have been previously studied for their non-skeletal benefits. In particular, questions regarding their role in the modulation of immunity have re-surfaced, in view of possible epidemiological links observed between COVID-19 and vitamin D levels in selected populations. In this review, we highlight potential mechanisms and summarise the evidence for and against the potential role of vitamin D supplementation in our fight against COVID-19.

Meteorological Condition and Air Pollution Exposure Associated with Vitamin D Deficiency: A Cross-Sectional Population-Based Study in China

Objective

The aim of this study was to investigate the status of Vitamin D deficiency and the effect of environmental factors on Vitamin D levels so as to provide theoretical support for public health promotion in this region.

Methods

A total of 22,387 subjects who underwent a physical examination at the center in the West China Hospital, Sichuan University, between April, 2018 and May, 2020 were enrolled in this study. Their data on gender, age, inspection date, serum 25 hydroxyvitamin D (25-(OH) D), parathyroid hormone (PTH), and total calcium were retrospectively reviewed. Next, the percentage of Vitamin D status was compared in different sex and age groups, and the fluctuation of Vitamin D level was described in relation to the change of environment. Finally, the univariable and multivariable linear regression analyses were performed to explore the risk and protective factors of Vitamin D deficiency.

Results

The proportion of Vitamin D deficiency in this area was 42.17%, and it was significantly higher among women and young people. The fluctuation trend of 25-(OH) D levels are consistent with temperature and solar radiation, and opposite to air quality, in the whole year. There was a positive relationship between 25-(OH) D levels with temperature and solar radiation; however, parathyroid hormone, female and AQI were negatively correlated with Vitamin D levels.

Conclusion

Vitamin D deficiency is common in subtropic areas, such as Sichuan Basin, which is related to solar radiation and air pollution.

Nutrihealth Study: Seasonal Variation in Vitamin D Status Among the Slovenian Adult and Elderly Population

Several studies conducted around the world showed substantial vitamin D insufficiency and deficiency among different population groups. Sources of vitamin D in the human body include ultraviolet B (UVB)-light-induced biosynthesis and dietary intake, but people's diets are often poor in vitamin D. Furthermore, in many regions, sun exposure and the intensity of UVB irradiation during wintertime are not sufficient for vitamin D biosynthesis. In Slovenia, epidemiological data about vitamin D status in the population were investigated through a national Nutrihealth study-an extension to the national dietary survey SI.Menu (2017/18). The study was conducted on a representative sample of 125 adult (18-64 years) and 155 elderly (65-74 years old) subjects, enrolled in the study in different seasons. Their vitamin D status was determined by measuring the serum 25-hydroxy-vitamin D (25(OH)D) concentration. Thresholds for vitamin D deficiency and insufficiency were 25(OH)D levels below 30 and 50 nmol/L, respectively. Altogether, 24.9% of the adults and 23.5% of the elderly were found to be vitamin D deficient, while an insufficient status was found in 58.2% and 62.9%, respectively. A particularly concerning situation was observed during extended wintertime (November-April); vitamin D deficiency was found in 40.8% and 34.6%, and insufficient serum 25(OH)D levels were observed in 81.6% and 78.8%, respectively. The results of the study showed high seasonal variation in serum 25(OH)D levels in both the adult and elderly population, with deficiency being especially pronounced during wintertime. The prevalence of this deficiency in Slovenia is among the highest in Europe and poses a possible public health risk that needs to be addressed with appropriate recommendations and/or policy interventions.

Vitamin D-Binding Protein in Pregnancy and Reproductive Health

Vitamin D-binding protein (VDBP), the main carrier of vitamin D, has recently been implicated in reproductive health and pregnancy outcomes including endometriosis, polycystic ovary syndrome (PCOS), pre-eclampsia, and gestational diabetes mellitus (GDM). Improved methods for measuring VDBP and an increased understanding of its role in biological processes have led to a number of newly published studies exploring VDBP in the context of pregnancy. Here, we synthesize the available evidence regarding the role of VDBP in reproductive health and pregnancy, and we highlight areas requiring further study. Overall, low levels of maternal serum VDBP concentrations have been associated with infertility, endometriosis, PCOS and spontaneous miscarriage, as well as adverse pregnancy outcomes including GDM, pre-eclampsia, preterm birth and fetal growth restriction. However, increased VDBP concentration in cervicovaginal fluid has been linked to unexplained recurrent pregnancy loss and premature rupture of membranes. Some genetic variants of VDBP have also been associated with these adverse outcomes. Further studies using more accurate VDBP assays and accounting for ethnic variation and potential confounders are needed to clarify whether VDBP is associated with reproductive health and pregnancy outcomes, and the mechanisms underlying these relationships.

'Scientific Strabismus' or two related pandemics: coronavirus disease and vitamin D deficiency

The WHO has announced the novel coronavirus disease (COVID-19) outbreak to be a global pandemic. The distribution of community outbreaks shows seasonal patterns along certain latitude, temperature and humidity, that is, similar to the behaviour of seasonal viral respiratory tract infections. COVID-19 displays significant spread in northern mid-latitude countries with an average temperature of 5–11°C and low humidity. Vitamin D deficiency has also been described as pandemic, especially in Europe. Regardless of age, ethnicity and latitude, recent data showed that 40 % of Europeans are vitamin D deficient (25-hydroxyvitamin D (25(OH)D) levels <50 nmol/l), and 13 % are severely deficient (25(OH)D < 30 nmol/l). A quadratic relationship was found between the prevalences of vitamin D deficiency in most commonly affected countries by COVID-19 and the latitudes. Vitamin D deficiency is more common in the subtropical and mid-latitude countries than the tropical and high-latitude countries. The most commonly affected countries with severe vitamin D deficiency are from the subtropical (Saudi Arabia 46 %; Qatar 46 %; Iran 33·4 %; Chile 26·4 %) and mid-latitude (France 27·3 %; Portugal 21·2 %; Austria 19·3 %) regions. Severe vitamin D deficiency was found to be nearly 0 % in some high-latitude countries (e.g. Norway, Finland, Sweden, Denmark and Netherlands). Accordingly, we would like to call attention to the possible association between severe vitamin D deficiency and mortality pertaining to COVID-19. Given its rare side effects and relatively wide safety, prophylactic vitamin D supplementation and/or food fortification might reasonably serve as a very convenient adjuvant therapy for these two worldwide public health problems alike.

Overweight & obese Australian adults and micronutrient deficiency

Background

Micronutrients have been implicated as an important factor in regulating various metabolic processes and thus playing a role in the aetiology of obesity. Many studies have been conducted worldwide that clearly show a direct link between obesity and micronutrient deficiencies. The aim of this study was to assess the nutritional status of overweight and obese Australian adults to see if there were any associations between BMI and serum micronutrient levels.

Methods

Baseline serum micronutrient data of overweight and obese individuals with a body mass index (BMI) between 25 and 40 kg/m² and aged between 18 and 65 years was compared to the clinical micronutrient reference ranges for associations between BMI and micronutrient status.

Results

There were significant negative associations between BMI and serum vitamin D (p = 0.044), folate (p = 0.025), magnesium (p = 0.010) and potassium (p = 0.023).

Conclusions

Overweight and obesity appears to impact on the bioavailability and utilisation of micronutrients with absorption, excretion, storage/distribution (fat sequestering, tissue dispersion), metabolism (catabolic losses, possibly oxidative), increased physiologic requirements, and lower absolute total dietary intake being the current theory for observed differences. While vitamins D, folate, magnesium and potassium showed a negative relationship to BMI, other micronutrients did not. This may be explained by the fortification of certain processed foods, or the possibility of overweight and obese people eating more to satisfy their nutritional requirements.

Prevalence and Predictors of Dietary and Nutritional Supplement Use in the Australian Army: A Cross-Sectional Survey

Dietary supplements (DSs) and nutritional supplements (NSs) can enhance performance, recovery or training adaptations, however, some substances, dosages, and usage protocols are unsafe. Knowledge of the type and extent of use within populations enables strategies to be formulated to promote safe and effective use (where needed) and to avoid adverse side effects. The purpose of this study was to understand DS and NS use by active-duty Australian soldiers. Surveys were distributed by e-mail and hard copy to eligible participants (n = 23,195). Respondents (males n = 1833; females n = 296) comprised 9.3% of the total population. Use of ≥1 DSs/week was reported by 76.4% of males and 86.8% of females, and use of ≥1 NSs/week was reported by 21.7% of males and 20.9% of females. The most commonly used supplements were protein or amino acids (55.6%), multivitamins and minerals (38.2%), other DSs (37.8%), individual vitamins and minerals (33.0%), and combination products (32.8%). Logistic regression revealed the number of DSs respondents used simultaneously was significantly different between males and females, age groups, BMI ranges, and body weight actions. Engagement in special operations was a significant predictor of the use of any DS, individual vitamin and minerals and multivitamin and minerals. Approximately 16% of regular DS users reported experiencing one or more side effects, with the most common being palpitations (10.6%), tingling or numbness in the face, fingers, arms, or legs (5.5%), tremors or shaking (2.9%), flushing (2.3%), headache (2.0%), abdominal pain (1.6%), anxiety (1.4%), and dizziness or confusion (0.9%). The results revealed more prevalent use of several categories of DSs and NSs among some subgroups. Ongoing surveillance of DS and NS use is important for tracking trends in use over time and gauging the effectiveness of any strategies employed to enhance the quality of supplement use.

The Effect of Yearly-Dose Vitamin D Supplementation on Muscle Function in Mice

Supplementation with vitamin D helps to alleviate weakness and fatigue seen with deficiency. However, large bolus doses appear to worsen the risk of falls. Whether this occurs as a direct result of muscle weakness is currently unknown. Thus, the aims of this study were to examine the muscle function following administration of high doses of vitamin D. Given the safety issues associated with bolus doses, experiments were conducted on C57BL6 mice. Mice at eight weeks of age with otherwise normal levels of vitamin D were supplemented for four weeks with a high dose (HIGH; n = 12) of vitamin D (20000 IU/kg food) designed to provide a year's worth of vitamin D. These mice were compared to another group who received that same yearly dose in a single bolus i.p. injection (YEAR; n = 12). Mice provided with standard mouse chow, which contained 1000 IU/kg food, and injected with the vitamin D vehicle were used as controls (CON; n = 16). Force and fatigue properties of hind limb fast- and slow-twitch muscles were measured. CON animals ingested vitamin D consistent with typical human supplementation. HIGH animals consumed significantly more food than the CON animals, such that they ingested more than a year's worth of vitamin D in four weeks. Despite this, there were few differences in the muscle function compared with CON. YEAR animals demonstrated lower absolute and relative forces in both muscles compared to the HIGH animals, as well as lower force during fatigue and early recovery. Large bolus doses of vitamin D appear to have detrimental effects on the skeletal muscle function, likely being a contributor to increased risk of falls observed with similar doses in humans. Mice ingesting the same amount over four weeks did not demonstrate the same deleterious effects, suggesting this may be a safe way to provide high vitamin D if required.

Vitamin D deficiency and its associated risk factors in normal adult population of Birjand, Iran

BACKGROUND

Vitamin D is required for calcium absorption, bone growth, and regulation of the immune system. Geographical location determines the intensity of the solar ultraviolet (UV) light as a significant determinant of vitamin D status in the many studies. This study was conducted to determine the status of vitamin D deficiency and its associated factors in adults of Birjand city, Iran (latitude: 32.87; longitude: 59.22).

METHODS

This descriptive-analytic study was performed by random stratified sampling on 400 subjects over 40 years of age in Birjand, who signed the consent form for participation. Data were collected in winter within one month from eight municipal health centers. Information regarding demographic characteristics, blood pressure, and anthropometric indices were collected, and blood samples were collected to measure 25-hydroxyvitamin D concentration.

RESULTS

The mean serum concentration of 25-OHD was 45.4 nmol/L. Twenty-six percent of subjects had vitamin D deficiency, 45.2% had insufficiency, and 28.8% of the subjects were healthy. The results of the multiple logistic regression showed that age (OR: 0.92, 95% CI = 0.89-0.96) and serum calcium concentration (OR: 0.52, 95% CI = 0.28-0.94) had a significant correlation with 25-OHD deficiency.

CONCLUSION

A high percentage of adults in the city of Birjand are suffering from vitamin D deficiency, which implies a need for extensive training and food enrichment programs, promoting healthy lifestyles, and exercise and walking.

Biomedical health profiles of unpaid family carers in an urban population in South Australia

OBJECTIVES

To compare the biomedical health profile and morbidity of adult carers with non-carers.

METHODS

The North West Adelaide Health Study (NWAHS) is a representative population-based longitudinal biomedical cohort study of 4056 participants aged 18 years and over at Stage One. Informal (unpaid) carers were identified in Stage 3 of the project (2008-2010). Risk factors, chronic medical conditions and biomedical, health and demographic characteristics using self-report and blood measured variables were assessed. Data were collected through clinic visits, telephone interviews and self-completed questionnaires. Risk factors included blood pressure, cholesterol/lipids, body mass index (BMI), smoking and alcohol intake. Chronic medical conditions included cardiovascular and respiratory diseases, diabetes, and musculoskeletal conditions. Blood measured variables were routine haematology, biochemistry, Vitamin D, and the inflammatory biomarkers high sensitivity C-Reactive Protein (hs-CRP), Tumor Necrosis Factor alpha (TNFα) and Interleukin-6 (Il-6).

RESULTS

The prevalence of carers aged 40 years and over was 10.7%, n = 191. Carers aged 40 years and over were more likely to assess their health status as fair/poor and report having diabetes, arthritis, anxiety and depression. They also reported insufficient exercise and were found to have higher BMI compared with non-carers. Significant findings from blood measured variables were lower serum Vitamin D and haemoglobin. Male carers had raised diastolic blood pressure, higher blood glucose, lower haemoglobin and albumin levels and slightly elevated levels of the inflammatory biomarkers TNFα and hs-CRP.

DISCUSSION AND CONCLUSIONS

This study confirms informal carers had different biomedical profiles to non-carers that included some chronic physical illnesses. It identifies that both female and male carers showed a number of risk factors which need to be considered in future caregiver research, clinical guidelines and policy development regarding carer morbidity.

Pharmacokinetics of a New Pharmaceutical Form of Vitamin D3 100,000 IU in Soft Capsule

Vitamin D deficiency is frequent in the general population and both subjects and health professionals could benefit from a broader range of vitamin D3 formulations. We conducted a single-dose, open-label, parallel-group, randomized bioequivalence study to compare a single dose of a newly developed vitamin D3 100,000 IU in a soft capsule (Group 1) with the reference drug vitamin D3 100,000 IU oral solution in ampoule (Group 2) in healthy volunteers over a four-month period. The primary endpoint was the area under the curve (AUC) of serum 25-hydroxyvitamin-D (25(OH)D) concentrations on Day 112. This study was conducted in France from February to June 2014 in 53 young adults with a mean age of 26.9 years. At baseline, low mean serum 25(OH)D levels were observed in both groups (10.6 ng/mL in Group 1 and 9.0 ng/mL in Group 2). On Day 112, the AUC of serum 25(OH)D concentration was 2499.4 ± 463.8 nmol/mL (7.8 ± 0.2 for LogAUC) for Group 1 and 2152.3 ± 479.8 nmol/mL (7.6 ± 0.2 for LogAUC) for Group 2. Bioequivalence of the two treatments was not demonstrated. Superiority of vitamin D3 100,000 IU soft capsule was observed with p = 0.029 for AUC and p = 0.03 for LogAUC using a non-parametric Wilcoxon test. The profile of the serum 25(OH)D concentration showed a significant difference in favor of Group 1 on Days 1, 3, 7, 14 and 90. Mean serum 25(OH)D concentrations in Group 1 were between 20 and 30 ng/mL during the four-month period and under 20 ng/mL throughout the study in Group 2, except on Day 112. Mean C_max for Group 1 was significantly higher (p = 0.002). Fourteen days were needed to reach T_max by more than half the subjects in Group 1 compared to 45 days in Group 2. Both treatments were well tolerated, with no severe or related adverse events reported. In conclusion, the pharmacokinetic profile of the new formulation of vitamin D3 100,000 IU soft capsule is superior to that of the oral solution in ampoule. The new formulation increased serum 25(OH)D levels to above 20 ng/mL and maintained levels from 20 ng/mL to 30 ng/mL for four months in late winter and spring.

Vitamin D deficiency in northern Taiwan: a community-based cohort study

Background

Vitamin D deficiency has become an important public health problem, however few studies have been conducted in subtropical countries, and the predictors of vitamin D deficiency in people with healthy renal function are unclear. The objective of this study was to evaluate the prevalence and factors associated with vitamin D deficiency in northern Taiwan.

Methods

The cross-sectional study was performed between August 2013 and August 2017, and included 3954 participants without chronic kidney disease (CKD) aged ≥30 years in northern Taiwan. Serum 25-hydroxyvitamin D [25(OH)-D] levels, biochemistry, sociodemographic variables (age, sex, education, occupation) and lifestyle habits (tea, coffee consumption and physical activities) were recorded. Associations between vitamin D status and these variables were examined using a regression model. The definition of deficiency was defined as a serum 25(OH)-D level < 20 ng/mL (50 nmol/L).

Results

The mean 25(OH)-D concentration was 28.9 ng/mL, and 22.4% of the study population had vitamin D deficiency. There was a significantly higher vitamin D deficiency ratio in the women compared to the men (22.9% vs 9.9%, p < 0.001). Vitamin D deficiency was most prevalent (38.4%) in those aged 30–39 years. Those with a graduate degree had the highest rate of vitamin D deficiency (31.5%). The predictors of vitamin D deficiency included female sex, young age, high education level, living in an urban area and physical inactivity. Tea consumption was negatively associated with vitamin D deficiency.

Conclusions

Vitamin D deficiency is prevalent in subtropical areas such as northern Taiwan in healthy individuals without CKD.

Changes to the frequency and appropriateness of vitamin D testing after the introduction of new Medicare criteria for rebates in Australian general practice: evidence from 1.5 million patients in the NPS MedicineInsight database

OBJECTIVES

To assess changes in the frequency of vitamin D testing and detection of moderate/severe vitamin D deficiency (<30 nmol/L) among adults after the introduction of new Medicare Benefits Schedule (MBS) rebate criteria (November 2014), and their relationship to sociodemographic and clinical characteristics.

DESIGN

Dynamic (open) cohort study SETTING: Primary care PARTICIPANTS: About 1.5 million 'active' patients aged 18+ years visiting a general practitioner and included in the National Prescribing Service MedicineInsight database.

OUTCOME MEASURES

The frequency of vitamin D testing (per 1000 consultations) and moderate/severe vitamin D deficiency (%) recorded between October 2013 and March 2016, stratified by the release of the new MBS criteria for rebate.

RESULTS

More patients were female (57.7%) and 30.2% were aged 60+ years. Vitamin D testing decreased 47% (from 40.3 to 21.4 tests per 1000 consultations) after the new MBS criteria, while the proportion of tests with no indication for being performed increased from 71.3% to 76.5%. The proportion of patients identified as moderate/severe vitamin D deficient among those tested increased from 5.4% to 6.5%. Practices located in high socioeconomic areas continued to have the highest rates of testing, but moderate/severe vitamin D deficiency detection remained 90% more frequent in practices from low socioeconomic areas after the rebate change. Furthermore, the frequency of individuals being tested was reduced independent of the patients' sociodemographic or clinical condition, and the gap in the prevalence of vitamin D deficiency detection between those meeting or not meeting the criteria for being tested remained the same. Moderate/severe vitamin D deficiency detection decreased slightly among patients with hyperparathyroidism or chronic renal failure.

CONCLUSIONS

Although the new criteria for rebate almost halved the frequency of vitamin D testing, it also lessened the frequency of testing among those at higher risk of deficiency, with only a small improvement in vitamin D deficiency detection.

Vitamin D Levels of Outpatients Admitted to a University Hospital in the Marmara Region of Turkey Over 3 Years

Background

Vitamin D regulates calcium and phosphorus metabolism, and it is essential for bone formation. Several factors can affect vitamin D levels in plasma. In present study we compare vitamin D levels of outpatients, who admit to Maltepe University Hospital between 2011 and 2013 and had vitamin D measurements regarding gender, age, and season.

Methods

Hospital records were evaluated to identify the outpatients with vitamin D levels and their gender, age, and vitamin D levels and the seasons of measurements were recorded.

Results

Data of 4860 subjects (74% female) were analyzed and 69.2% were between 18-64 years old. Vitamin D levels were as follows: 43.1% ≤ 10 ng/mL, 31.9% between 10 ng/mL and 20 ng/mL, 16.1% between 20 ng/mL and 30 ng/mL, and only 8.9% ≥ 30 ng/mL. The number of females with vitamin D levels < 10 ng/mL was significantly higher than that of males, while the number of males with vitamin D levels between 10 ng/mL and 20 ng/mL was significantly higher than that of females (P = 0.001) for each of the individuals, 6.2% and 11.1% had sufficient levels in winter and summer, respectively. Overall, it was observed that 6.6% of individuals between 18-44 years old, 8.2% of individuals between 45-64 years old and 10.3% of individuals over 65 years old had vitamin D levels > 30 ng/mL.

Conclusions

The prevalence of vitamin D deficiency in outpatients of Maltepe University Hospital in Marmara region was 75% (< 20 ng/mL).

Relationship between Vitamin D Deficiency, Diabetes, and Obesity

AIM

This study aimed to assess the prevalence of VDD in Saudi Arabia, revealing the lifestyle and nutritional habits; and assesses the association between VDD, Diabetes Mellitus, and obesity.

METHODS

A descriptive, cross-sectional, and correlational design was used in this study. A convenience sampling method of 350 participants participated in the study.

RESULTS

The results revealed that the probability of having vitamin D Deficiency was higher among females (OR = 2.06, p > .05); younger age-whereby with each one year decrease in age there was about 0.03 probability of having Vitamin D Deficiency (B = -0.03; p > .05); individuals with higher incomes (OR = 1.44, p > .05); smokers (OR = 0.08, p > .05); and a lack of exposure to the sun (OR = 8.50; p > .05). In addition, exercise is also a predictor of Vitamin D deficiency (OR = 3.8; p > .05). Moreover, less Vitamin D intake (OR 9.7; p > .05), less intake of Calcium (OR = 12.2, p > .05); In addition increase one unit in the BMI, cholesterol, LDL, HDL, and FBS increased the log odd of having liability of Vitamin D deficiency by 3.2; 1.9, 1.8, 1.0, and 2.4 (p > .05).

CONCLUSION

Vitamin D Deficiency was prevalent in both males and females across different age groups in the citizens of Saudi. Because of the connection between Vitamin D Deficiency and main chronic disease, it is necessary to emphasize the need to recognize Vitamin D Deficiency screening for risk factors. It may be reasonable for the nutritionists, nurses, and physicians, to encourage the community on approaches to enhance dietary Vitamin D or suggest supplementation.

Vitamin D status in Thai dermatologists and working-age Thai population

This study aimed to determine the prevalence of vitamin D insufficiency among Thai dermatologists compared with the general working-age population in Bangkok. A cross-sectional study was conducted in healthy Thai physicians who had at least 1 years' experience in dermatology practise and a subsample of the general Thai population from the Fourth National Health Survey. Serum 25-hydroxyvitamin D (25[OH]D), a combination of 25(OH)D2 and 25(OH)D3, levels in both groups were measured using liquid chromatography coupled with mass spectrometry. The majority of dermatologists were of Fitzpatrick skin type III (n = 61, 61.3%) or IV (n = 32, 33.3%). The mean serum 25(OH)D and 25(OH)D3 levels were 18.9 and 18.2 ng/mL, respectively, whereas the corresponding levels in the general population were 26.5 and 25.8 ng/mL. None of the dermatologist had serum 25(OH)D sufficiency (>30 ng/mL), 38 (38.78%) had vitamin D insufficiency (20-30 ng/mL) and 60 (61.22%) had vitamin D deficiency (<20 ng/mL). The frequency of vitamin D deficiency in dermatologists was significantly higher than in the general population (61.2% vs 19.2%, P < 0.001). Ninety percent of dermatologists used sunscreen daily and spent time mostly indoors. Dermatologists used physical sun-protection more than half of the time when outdoors, for example, a book or paper as a sunshade (70.3%), an umbrella (48.4%), a long-sleeved shirt (20.4%) or a hat (9.7%). In conclusion, dermatologists showed a remarkably high prevalence of vitamin D deficiency which may be due to inadequate exposure to sunlight, regular use of sunscreen and practicing various sun-protection activities.

Antioxidants in Personalized Nutrition and Exercise

The present review highlights the idea that antioxidant supplementation can be optimized when tailored to the precise antioxidant status of each individual. A novel methodologic approach involving personalized nutrition, the mechanisms by which antioxidant status regulates human metabolism and performance, and similarities between antioxidants and other nutritional supplements are described. The usefulness of higher-level phenotypes for data-driven personalized treatments is also explained. We conclude that personally tailored antioxidant interventions based on specific antioxidant inadequacies or deficiencies could result in improved exercise performance accompanied by consistent alterations in redox profile.

Serum 25-hydroxyvitamin D status, quantitative ultrasound parameters, and their determinants in Greek population

Vitamin D deficiency and quantitative ultrasound measurements are associated with bone fragility. We assessed these parameters and their correlates. 87.7% of the population has vitamin D inadequacy and this correlated with lifestyle factors. These results contribute to epidemiological data needed for population guidelines for bone health.

PURPOSE

Vitamin D deficiency and quantitative ultrasound (QUS) parameters are among the most important clinical risk factors of bone fragility. Few data are available for Greek population. The aim of the study was to evaluate the serum 25-hydroxyvitamin D [25(OH)D] level and their determinants, as well as QUS parameters in Greek population.

METHODS

OSTEOS is an observational cross-sectional study conducted from June 2010 to July 2012. Nine hundred seventy adults were recruited from rural and urban areas throughout Greece and completed the appropriate questionnaire. Serum 25(OH)D measured by enzyme immunoassay, QUS parameters, broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (SI), was assessed with an Achilles device. Univariate Analysis of Variance was used for the assessment of serum 25(OH)D determinants.

RESULTS

Mean serum 25(OH)D of the total population was 20,00 ± 8,00 ng/mL. Females had lower levels than males. The negative determinants of serum 25(OH)D in the total population were the female sex and the winter-spring season of sampling while age proved negative association solely in obese subjects. Positive determinants of vitamin D status were summer sun exposure and organized physical activity as expected. Urban had lower SOS and SI than rural residents. Individuals with 25(OH)D ≥ 20 ng/mL had higher SOS than those with 25(OH)D < 20 ng/mL. BUA, SOS, and SI are positively correlated with organized physical activity and negatively with PTH.

CONCLUSIONS

This study reports that vitamin D deficiency is highly prevalent among healthy Greek men and women, demonstrates the multifactorial causation of 25(OH)D levels, and points out that further research is required to determine more factors related to vitamin D status and bone health.

Vitamin D deficiency in patients with cluster headache: a preliminary study

Background

Cluster headache is famous for attacks with seasonal and diurnal periodicity. This diurnal and seasonal variation might be related to sunlight and vitamin D metabolism. We investigated the serum vitamin D levels in patients with cluster headache.

Methods

We enrolled patients with cluster headache and age- and sex-matched migraineurs and normal controls. From October 2016 to March 2018, non-fasting serum 25(OH)D concentrations were measured using a chemiluminescent immunoassay. Vitamin D deficiency was defined as a concentration < 20 ng/mL.

Results

The study enrolled 28 patients with cluster headache, 36 migraineurs, and 36 normal controls. In the patients with cluster headache, the serum 25(OH)D concentration averaged 14.0 ± 3.9 ng/mL and 92.8% had vitamin D deficiency. There was no significant difference among the patients with cluster headache, migraineurs, and controls. In the patients with cluster headache, there was no difference in the serum 25(OH)D concentrations between men and women, cluster and remission periods, first and recurrent attack, presence and absence of daily or seasonal periodicity, and 3-month recurrence. In the 14 patients with seasonal periodicity, patients with periodicity of winter to spring had a trend of lower serum 25(OH)D concentrations than those with periodicity of summer to autumn (12.30 ± 1.58 vs. 16.96 ± 4.69 ng/mL, p = 0.097).

Conclusions

Vitamin D deficiency is common in patients with cluster headache, but the role of vitamin D deficiency is uncertain, except for its seasonal influence.

Electronic supplementary material

The online version of this article (10.1186/s10194-018-0886-7) contains supplementary material, which is available to authorized users.

Dietary Acid Load, IGF-1 Single Nucleotide Polymorphism and Bone Resorption among Postmenopausal Chinese Women

The interaction of dietary and genetic factors may affect the development of bone deterioration. This study investigated whether the effects of dietary acid load (DAL) on bone loss in postmenopausal Chinese women were moderated by the insulin-like growth factor-1 (IGF-1) single nucleotide polymorphism, a known gene that plays a role in the regulation of bone formation and bone remodeling. A total of 217 healthy participants were recruited from the National Council of Senior Citizens Organizations Malaysia. Serum collagen type 1 cross-linked C-telopeptide was used as a surrogate bone marker to assess bone resorption and Agena^® MassARRAY genotyping analysis was used to identify the signaling of IGF-1 rs35767. The dietary acid load was measured by potential renal acid load score while physical activity was ascertained using the Global Physical Activity Questionnaire. Hierarchical regression was applied to test the main and interaction effects of DAL and IGF-1 genotypes in bone resorption. The result supported the diet-dependent acid-base balance theory that higher DAL was positively associated with bone resorption (β = 0.152, p = 0.031, F_(6,207) = 2.11, sig-F = 0.036, R² = 0.079). However, the results indicated that there was no significant correlation between IGF-1 and bone resorption, or any significant interaction between DAL and IGF-1. In conclusion, there was no moderating effect of IGF-1 on the relationship between DAL and bone resorption.

Global Overview of Vitamin D Status

Vitamin D deficiency occurs all over the world, mainly in the Middle East, China, Mongolia, and India. This article focuses on the vitamin D status in adults. Risk groups include older persons, pregnant women, and non-Western immigrants. Adequate vitamin D status, defined as serum 25-hydroxyvitamin D greater than 50 nmol/L, is present in less than 50% of the world population, at least in winter. Preventative strategies, such as increasing fish consumption, fortification of foods, use of vitamin D supplements, and advice for moderate sunlight exposure, are warranted.

Low-dose vitamin D supplementation and incident frailty in older people: An eight year longitudinal study

Hypovitaminosis D is associated with frailty, but if vitamin D supplementation may prevent the onset of frailty is poorly known. Therefore, we aimed to investigate whether vitamin D supplementation is associated with a lower risk of frailty. In this longitudinal study, 4,421 individuals at high risk or having knee osteoarthritis free from frailty at baseline (mean age: 61.3, females=58.0%) were followed for 8 years. Details regarding vitamin D supplementation were captured by asking whether the participant took vitamin D during the previous year, at least once per month. Frailty was defined using the Study of Osteoporotic Fracture (SOF) index as the presence of at least two of the following criteria: (i) weight loss≥5% between baseline and any subsequent follow-up visit; (ii) inability to do five chair stands; (iii) low energy level according to the SOF definition. Multivariable Cox's regression analyses, calculating hazard ratios (HRs) with 95% confidence intervals (CIs), were undertaken. At baseline 69.7% took vitamin D supplements in the previous year, with a mean dose of 384±157 IU per day. During the 8-year follow-up, no difference in the incidence of frailty was evident by vitamin D supplementation status at baseline, even after adjusting for 13 baseline confounders (HR=0.95; 95% CI: 0.72-1.25). Similar results were obtained using the propensity score (HR=0.95; 95% CI: 0.71-1.25) or age- and sex-matched controls (HR=1.00; 95% CI: 0.75-1.33). In conclusion, low-dose vitamin D supplementation was not associated with any decreased risk of frailty during eight years of follow-up in a large cohort of North American people. Future large-scale trials with high doses of oral vitamin D and longer follow-up are needed to confirm/refute our findings.

Association of Sun Exposure, Skin Colour and Body Mass Index with Vitamin D Status in Individuals Who Are Morbidly Obese

Vitamin D deficiency is a common issue, particularly in obese populations, and is tested by assessing serum 25(OH)D concentrations. This study aimed to identify factors that contribute to the vitamin D status in fifty morbidly obese individuals recruited prior to bariatric surgery. Data collected included serum 25(OH)D concentrations, dietary and supplement intake of vitamin D, sun exposure measures, skin colour via spectrophotometry, and genotype analysis of several single nucleotide polymorphisms in the vitamin D metabolism pathway. Results showed a significant correlation between serum 25(OH)D concentrations and age, and serum 25(OH)D and ITAC score (natural skin colour). Natural skin colour accounted for 13.5% of variation in serum 25(OH)D, with every 10° increase in ITAC score (i.e., lighter skin) leading to a 9 nmol/L decrease in serum 25(OH)D. Multiple linear regression using age, ITAC score, and average UV index in the three months prior to testing, significantly predicted serum 25(OH)D concentrations (R² = 29.7%). Single nucleotide polymorphisms for all vitamin D genes tested, showed lower serum 25(OH)D for those with the rare genotype compared to the common genotype; this was most pronounced for fok1 and rs4588, where those with the rare genotype were insufficient (<50 nmol/L), and those with the common genotype were sufficient (≥50 nmol/L). Assessing vitamin D status in individuals with morbid obesity requires testing of 25(OH)D, but potential risk factors for this population include natural skin colour and age.

Predictors and correlates of serum 25-hydroxyvitamin D concentrations in young women: results from the Safe-D study

Vitamin D deficiency is a global public health concern. Studies of serum 25-hydroxyvitamin D (25(OH)D) determinants in young women are limited and few include objective covariates. Our aims were to define the prevalence of vitamin D deficiency and examine serum 25(OH)D correlates in an exploratory study of women aged 16–25 years. We studied 348 healthy females living in Victoria, Australia, recruited through Facebook. Data collected included serum 25(OH)D assayed by liquid chromatography-tandem MS, relevant serum biochemistry, soft tissue composition by dual-energy X-ray absorptiometry, skin melanin density, Fitzpatrick skin type, sun exposure using UV dosimeters and lifestyle factors. Mean serum 25(OH)D was 68 (sd27) nmol/l and 26 % were vitamin D deficient (25(OH)D <50 nmol/l). The final model explained 56 % of 25(OH)D variance. Serum sex hormone-binding globulin levels, creatinine levels, sun exposure measured by UV dosimeters, a positive attitude towards sun tanning, typically spending >2 h in the sun in summer daily, holidaying in the most recent summer period, serum Fe levels, height and multivitamin use were positively associated with 25(OH)D. Fat mass and a blood draw in any season except summer was inversely associated with 25(OH)D. Vitamin D deficiency is common in young women. Factors such as hormonal contraception, sun exposure and sun-related attitudes, as well as dietary supplement use are essential to consider when assessing vitamin D status. Further investigation into methods to safely optimise vitamin D status and to improve understanding of the impact of vitamin D status on long-term health outcomes is required.

Longitudinal changes in serum 25-hydroxyvitamin D in the Dallas Heart Study

CONTEXT

While the prevalence of vitamin D deficiency is well described in various populations, limited data are available regarding longitudinal variation in serum 25-hydroxyvitamin D concentrations.

OBJECTIVES

To evaluate the temporal trends in serum 25(OH)D, prevalence of vitamin D deficiency and factors influencing these trends.

PARTICIPANTS, DESIGN AND SETTING

Adults enrolled in the Dallas Heart Study, a longitudinal, probability-based, multiethnic, population study in Dallas, Texas, USA.

MAIN OUTCOME MEASURES

Prevalence of vitamin D deficiency and predictors of change in serum 25(OH)D.

RESULTS

A total of 2045 participants had serum 25(OH)D measured on two occasions (2000-2002 and 2007-2009) at a median interval of 7 years. Serum 25(OH)D decreased (42.7-39.4 nmol/L, P<.001) and the prevalence of vitamin D deficiency [25(OH)D <50 nmol/L] increased significantly (60.6%-66.4%, P<.0001) despite vitamin D supplementation increasing over the interval (7.2%-23.0%; P<.0001). In a multivariable model adjusting for sex, race, BMI, age, season of blood draw, smoking and exercise, a greater decline in serum 25(OH)D was noted in men compared with women (-8.0 vs -3.5 nmol/L, P<.0001), in participants of Hispanic ethnicity vs White and Black ethnicity (P<.0001), in nonobese vs obese participants (-7.2 vs -4.0 nmol/L, P=.005) and in nonusers vs users of vitamin D supplements (-5.7 vs -1.7 nmol/L, P=.032).

CONCLUSIONS

Despite increased vitamin D supplementation, serum 25(OH)D decreased in an ethnically diverse cohort of Dallas County residents between 2000-2002 and 2007-2009. Features most predictive of a decline in serum 25(OH)D include male sex, Hispanic ethnicity and weight gain.

[Prevalence of hypovitaminosis D and associated factors in Spanish population of school children and adolescents]

Objetivo

Analizar la prevalencia de hipovitaminosis D y factores asociados en escolares y adolescentes residentes en una región del norte peninsular.

Diseño

Estudio descriptivo transversal (muestreo de conveniencia).

Emplazamiento

Atención primaria.

Participantes

Fueron incluidos 602 sujetos sanos de raza caucásica con edades comprendidas entre 3,1 y 15,4 años.

Mediciones principales

Se ha calculado la prevalencia de hipovitaminosis D (variable dependiente) según los criterios de la US Endocrine Society: deficiencia (calcidiol < 20 ng/ml), insuficiencia (calcidiol: 20-29 ng/ml) y suficiencia (calcidiol ≥ 30 ng/ml). Se han registrado como variables independientes: sexo, edad, índice de masa corporal, lugar de residencia y estación del año, analizándose su asociación con la hipovitaminosis D mediante regresión logística múltiple.

Resultados

La prevalencia de hipovitaminosis D era del 60,4% (insuficiencia: 44,6%; deficiencia: 15,8%). Las variables asociadas con la hipovitaminosis D eran el sexo femenino (OR: 1,6; IC 95%: 1,1-2,3), la edad puberal (OR: 1,8; IC 95%: 1,2-2,6), las estaciones de otoño (OR: 9,5; IC 95%: 4,8-18,7), invierno (OR: 8,8; IC 95%: 4,5-17,5) y primavera (OR: 13,2; IC 95%: 6,4-27,5), el entorno urbano (OR:1,6; IC 95%: 1,1-2,2) y la obesidad severa (OR: 4,4; IC 95%: 1,9-10,3).

Conclusiones

En la población infantojuvenil existe una alta prevalencia de hipovitaminosis D, y los factores asociados son el sexo femenino, la edad puberal, el otoño, el invierno y la primavera, la obesidad severa y el entorno urbano. Habría que considerar la necesidad de administrar suplementos vitamínicos o ingerir mayores cantidades de sus fuentes dietéticas naturales y/o alimentos enriquecidos durante los meses de otoño, invierno y primavera.

Is there role for vitamin D in the treatment of chronic pain?

Chronic pain is highly prevalent in the developed world, and levels of vitamin D are often lower among those with chronic pain conditions than those without. Supplementation of vitamin D has been investigated as a potential independent treatment for chronic pain. This paper presents an overview of the scientific evidence and provides recommendations for use of vitamin D in clinical practice with chronic pain patients.

Vitamin D (FokI) Receptor Gene Polymorphism is associated with Vitamin D Deficiency and Chronic Musculoskeletal Pain. A meta-analysis

Background: Musculoskeletal pain is the most common chronic pain experienced by older adults. The aim of this study is to explore the associations between vitamin D (FOKI) receptor gene polymorphism (VDR) and vitamin D deficiency (VDD) and chronic musculoskeletal pain. Methods: Cross-sectional studies published in English from January 2000 to January 2015which reported prevalence of chronic pain (CP) and chronic musculoskeletal pain (CMP) were included in this systematic review and meta-analysis. A heat map was used to visualize and observe the correlation between VDR and CMP, CP and VDD. Results: 20 studies (N = 216,365) were included in the analysis, which showed an overall pooled prevalence estimate of CMP and CP as 30.6 per 100 (95 % CI: 30.59, 30.69) and 27.9 per 100 (95 % CI: 27.68, 28.24) respectively. The heat map clustering analysis visualizes the similarity between CP and CMP. Moreover, a direct correlation was observed between the three disease conditions (namely CMP, CP, and VDD) and FokI VDR polymorphism (FF). Spearman's correlation analyses with adjusted r² revealed that there is a statistically significant interaction effect of the FF genotype and VDD on CMP (r² = 0.19, p = 0.03), a marginally significant interaction effect of the ff genotype and VDD on CMP (r² = 0.11, p = 0.08). VDD was also associated with increased CMP (r² = 0.19, p = 0.028). The pooled estimates of the prevalence of CMP in this review were found to be high. Conclusion: FokI VDR gene polymorphism (FF) plays an important role in the relationship between VDD and CMP.

Winter to summer change in vitamin D status reduces systemic inflammation and bioenergetic activity of human peripheral blood mononuclear cells

Background

Vitamin D status [25(OH)D] has recently been reported to be associated with altered cellular bioenergetic profiles of peripheral blood mononuclear cells (PBMCs). No study has tracked the seasonal variation of 25(OH)D and its putative influence on whole body energy metabolism, cellular bioenergetic profiles, inflammatory markers and clinical chemistry.

Material and methods

Whole body energy metabolism and substrate utilisation were measured by indirect calorimetry. PBMCs obtained from the same subjects were isolated from whole blood, counted and freshly seeded. Bioenergetic analysis (mitochondrial stress test and glycolysis stress test) was performed using the Seahorse XF^e96 flux analyser. 25(OH)D was assessed using the Architect immunoassay method.

Results

25(OH)D increased by a median (IQR) of 14.40 (20.13) nmol/L (p<0.001) from winter to summer and was accompanied by significant improvements in indices of insulin sensitivity, McAuley's index (p=0.019) and quantitative insulin sensitivity check index (p=0.028). PBMC mitochondrial parameters basal respiration, non-mitochondrial respiration, ATP production, proton leak, and maximal respiration decreased in summer compared to winter. Similarly, PBMC glycolytic parameters glycolytic activity, glucose response, and glycolytic capacity were all reduced in summer compared to winter. There was also a trend for absolute resting metabolic rate (RMR) to decrease (p=0.066). Markers of systemic inflammation MCP-1, IL-6, IL-8, IL-10, and IL-12p70 decreased significantly in summer compared to winter. Participants who entered winter with a low 25(OH)D (<50 nmol/L), had the greatest alteration in bioenergetic parameters in summer, relative to those with winter 25(OH)D concentrations of 50–75 nmol/L or >75 nmol/L. The absolute change in 25(OH)D was not associated with altered bioenergetics.

Conclusion

Seasonal improvements in 25(OH)D was associated with reduced systemic inflammation, PBMC bioenergetic profiles and whole body energy metabolism. These observational changes in PBMC bioenergetics were most pronounced in those who had insufficient 25(OH)D in winter. The data warrants confirmation through cause and effect study designs.

•

Inflammation and clinical biochemistry improved in summer versus winter.

•

Seasonal improvements in 25(OH)D modulated the bioenergetic profile of PBMCs.

•

Maintaining 25(OH)D >50 nmol/L may be important for bioenergetic function.

Independent association between socioeconomic indicators and macro- and micro-nutrient intake in Switzerland

BACKGROUND

Socioeconomic differences in diet are rarely assessed with more than one indicator. We aimed to assess differences in macro- and micro-nutrient intake in both sexes according to education, income, and occupation.

METHODS

We used data from validated food frequency questionnaire measured dietary intake in 5087 participants (2157 women) from yearly adult population-based cross-sectional surveys conducted from 2005 to 2012 in the canton of Geneva, Switzerland. We used two ANOVA models: age-adjusted and multivariable adjusted simultaneously for all three socioeconomic indicators.

RESULTS

Low-education men consumed more calcium but less vitamin D than high-education men; low-income men consumed less total and animal protein (80.9±0.9 vs 84.0±0.6 g/d; 55.6±1.0 vs 59.5±0.7 g/d) and more total carbohydrates and sugars (246±2 vs 235±2 g/d; 108±2 vs 103±1 g/d) than high-income men. Occupation and diet showed no association. Low-education women consumed less vegetable protein (20.7±0.2 vs 21.6±0.2 g/d), fibre (15.7±0.3 vs 16.8±0.2 g/d), and carotene (4222±158 vs 4870±128 μg/d) than high-education women; low-income women consumed more total carbohydrates (206±2 vs 197±1 g/d) and less monounsaturated fat (27.7±0.4 vs 29.3±0.3 g/d) than high-income women. Finally, low-occupation women consumed more total energy (1792±27 vs 1714±15 kcal/d) and total carbohydrates (206±2 vs 200±1 g/d), but less saturated fat (23.0±0.3 vs 24.4±0.2 g/d), calcium (935±17 vs 997±10 mg/d) and vitamin D (2.5±0.1 vs 2.9±0.1 μg/d), than high-occupation women.

CONCLUSION

In Switzerland, the influence of socioeconomic factors on nutrient intake differs by sex; income and education, but not occupation, drive differences among men; among women, all three indicators seem to play a role. Interventions to reduce inequalities should consider the influence of education, income, and occupation in diet to be most effective.

Prevalence of hypovitaminosis D and associated factors in obese Spanish children

Background/Objectives:

Vitamin D deficiency may contribute to endocrine health and disease (diabetes, autoimmune thyroid diseases, polycystic ovarian syndrome, etc.). The aim of this study was to determine the prevalence and specific factors for hypovitaminosis D among children stratified by body mass index (BMI) in Northern Spain.

Subjects/Methods:

A cross-sectional clinical (sex, age, season of study visit, place of residence and BMI) and blood testing (calcium, phosphorous, calcidiol and parathyroid hormone (PTH)) were accomplished in 546 Caucasian individuals (aged 3.2–15.8 years). The BMI (Z-score) allowed establishing four groups: normal, overweight, obesity and severe obesity. The criteria of the US Endocrine Society were used for the definition of hypovitaminosis D.

Results:

Calcidiol levels were significantly higher in normal and overweight groups (P=0.001), whereas PTH levels were significantly higher in obesity and severe obesity groups (P=0.001). Hypovitaminosis D prevalence was significantly higher in severe obesity (81.1%) and obesity (68.2%) groups, whereas was lowest in overweight (55%) and normal (58.1%) groups (P=0.001). There was a negative correlation between calcidiol and PTH levels (P<0.01). Female (90.9%), adolescent group (88,2%), winter (100%) and autumn (82.4%) time and urban residence (94.1%) imply a higher prevalence of hypovitaminosis D in subjects with severe obesity (P<0.001). Female, puberal age, autumn, winter and spring time, urban residence and severe obesity were found to be independent predictors for hypovitaminosis D.

Conclusions:

Severe obesity could be considered as an associated factor for vitamin D deficiency, and, owing to its high prevalence, the implementation of systematic screening and hypovitaminosis treatment programs would be particularly useful.

Serum 25-hydroxyvitamin D and bone turnover markers in Palestinian postmenopausal osteoporosis and normal women

This study evaluated the association of vitamin D and bone markers with the development osteoporosis in Palestinian postmenopausal women. Even though vitamin D deficiency was very high for the recruited subjects, it was not associated with osteoporosis except for bones of the hip. Age and obesity were the strongest determining factors of the disease.

PURPOSE

The purpose of this study was to investigate the association of bone mineral density (BMD) with serum vitamin D levels, parathyroid hormone (PTH), calcium, obesity, and bone turnover markers in Palestinian postmenopausal women.

METHODS

Three hundred eighty-two postmenopausal women (≥45 years) were recruited from various women clinics for BMD assessment (131 women had osteoporosis and 251 were normal and served as controls). Blood samples were obtained for serum calcium, PTH, 25(OH)D, bone formation (N-terminal propeptide (PINP)), and bone resorption (serum C-terminal telopeptide of type I collagen (CTX1)) markers.

RESULTS

Women with osteoporosis had statistically significant lower mean weight, height, body mass index (BMI), and serum calcium (p < 0.05) compared to controls. No significant differences were detected between the mean values of bone turnover markers (CTX and PINP), 25(OH)D, and PTH of the two groups. Women with vitamin D deficiency (severe and insufficiency) represented 85.9% of the study subjects. Multiple and logistic regression showed that age and BMI significantly affected BMD and vitamin D had a significant association with BMD only at the lumbar spine. BMI was positively correlated with BMD and PTH but negatively correlated with vitamin D. Logistic regression showed that the odds ratio (OR) for having osteoporosis decreased with increasing BMI (overweight OR = 0.11, p = 0.053; obese OR = 0.05, p = 0.007).

CONCLUSIONS

There was no direct correlation between BMD and PTH, bone turnover markers, and vitamin D except at the lumbar spine. A negative correlation between BMD and age and a positive correlation with BMI were observed. The protective effect of obesity on osteoporosis was complicated by the effect of obesity on vitamin D and PTH.

Assessment of vitamin D levels, awareness among Lebanese pharmacy students, and impact of pharmacist counseling

Vitamin D inadequacy, frequently underdiagnosed, affects people of all age groups worldwide. This prospective study aims at determining the percentage of inadequate vitamin D levels among students and evaluating the impact of pharmacist counseling on raising the awareness of the importance of sun exposure and adequate vitamin D intake. A total of 160 university students were recruited. Blood samples were taken to check the vitamin D, calcium, and phosphorous levels. Vitamin D levels ⩽30 ng/mL were defined as inadequate. Scores were given to the questions and aimed at gathering patient knowledge about vitamin D before and after pharmacist counseling. A total of 115 (71.87%) patients had vitamin D levels <30 ng/mL, with a mean vitamin D serum level of 16.80 ± 5.85 ng/mL. The mean level of calcium was 9.51 ± 1.23 mg/dL and, of phosphorus 3.62 ± 0.95 mg/dL. The mean difference in the knowledge score of the recommended daily amount of vitamin D before and after pharmacist counseling was 2.81 versus 5.88 (p < 0.001). Concerning patient education for diseases and drugs that affect vitamin D levels, pharmacist counseling was effective in raising the awareness (p < 0.001). Given that vitamin D inadequacy is linked to many disease progressions, it is important that health professionals provide interventional strategies and education measures to correct inadequate levels in patients of all age groups.

NRAS and EPHB6 mutation rates differ in metastatic melanomas of patients in the North Island versus South Island of New Zealand

Melanoma, the most aggressive skin cancer type, is responsible for 75% of skin cancer related deaths worldwide. Given that New Zealand (NZ) has the world's highest melanoma incidence, we sought to determine the frequency of mutations in NZ melanomas in recurrently mutated genes. NZ melanomas were from localities distributed between North (35°S-42°S) and South Islands (41°S-47°S). A total of 529 melanomas were analyzed for BRAF exon 15 mutations by Sanger sequencing, and also by Sequenom MelaCarta MassARRAY. While, a relatively low incidence of BRAFV600E mutations (23.4%) was observed overall in NZ melanomas, the incidence of NRAS mutations in South Island melanomas was high compared to North Island melanomas (38.3% vs. 21.9%, P=0.0005), and to The Cancer Genome Atlas database (TCGA) (38.3% vs. 22%, P=0.0004). In contrast, the incidence of EPHB6G404S mutations was 0% in South Island melanomas, and was 7.8% in North Island (P=0.0002). Overall, these data suggest that melanomas from geographically different regions in NZ have markedly different mutation frequencies, in particular in the NRAS and EPHB6 genes, when compared to TCGA or other populations. These data have implications for the causation and treatment of malignant melanoma in NZ.

Determinants of vitamin D status in young adults: influence of lifestyle, sociodemographic and anthropometric factors

BACKGROUND

Very few studies have investigated the determinants of circulating 25-hydroxyvitamin D (25[OH]D) in young adults (18-25 years old) using a set of variables that include lifestyle, sociodemographic, and anthropometric data. Our aim was to investigate the association between these variables and vitamin D status in a sample of untreated young adults.

METHODS

A total of 738 young adults were enrolled in a (June cross-sectional study 2012 to May 2014) and were recruited from educational institutions in the Copenhagen area. For multivariate logistic regression subjects was categorized based on 25[OH]D in serum into; vitamin D sufficiency (S-25[OH]D > 50 nmol/L), vitamin D insufficiency (25 nmol/L ≤ S-25[OH]D ≤ 50 nmol/L), vitamin D deficiency (S-25[OH]D < 25 nmol/L). Information on lifestyle factors and education was obtained by self-reported questionnaires.

RESULTS

700 subjects with a valid measurement of S-25[OH]D and a completed questionnaire was analysed. 238 had vitamin D insufficiency, 135 had vitamin D deficiency of which 13 had severe vitamin D deficiency (S-25[OH]D < 12.5 nmol/L). The relative risk (RR) for vitamin D deficiency was highest for men 2.09 (1.52, 2.87); obese subjects 2.00 (1.27, 3.15); smokers 1.33 (1.02, 1.73); subjects who exercised 0-½ hours a week 1.88 (1.21, 2.94); and subjects who consumed fast food once a week 1.59 (1.05, 2.43). The relative risk was significantly lower for subjects who were studying for a Bachelor's degree (0.40 (0.23, 0.68). For vitamin D insufficiency, the highest RR was again for men 1.31 (1.06, 1.61); obese subjects 1.57 (1.17, 2.11); and subjects who exercised 0-½ hours a week 1.51 (1.11, 2.06).

CONCLUSION

In this study of young adults, vitamin D deficiency was highly prevalent. Modifiable factors such as smoking, maintenance of normal BMI, and physical activity are all potential targets for interventional trials to determine the causal order; such knowledge would be useful in improving S-25[OH]D in young adults. The small group with severe vitamin D deficiency warrants increased attention.