Impact of high latitude, urban living and ethnicity on 25-hydroxyvitamin D status: A need for multidisciplinary action?

Evaluating low and high vitamin D levels in Ecuadorian cities from 2018 to 2022: interrupted time series and a cross-sectional study

OBJECTIVES

To identify differences in the mean vitamin D concentrations in samples obtained from a private laboratory in Quito and to explore their relationship with the pre-pandemic and pandemic periods spanning from 2018 to 2022.

DESIGN

A combination of an interrupted time series design and a retrospective cross-sectional approach.

SETTING AND PARTICIPANTS

The study involved 9285 participants who had their 25-hydroxyvitamin D (25(OH)D) levels tested at a well-known private laboratory in Quito, Ecuador, from 2018 to 2022.

PRIMARY AND SECONDARY OUTCOME MEASURES

The 25(OH)D levels were analysed and assessed for correlations with age, and the year the measurements were taken.

RESULTS

The mean 25(OH)D level was 27.53 ng/mL (± 14.11). Approximately 68.8% of participants had serum 25(OH)D levels of less than 30 ng/mL, and 0.6% showed potential harm from excess 25(OH)D, with levels over 100 ng/mL. The analysis indicated a significant monthly increase of 0.133 units in 25(OH)D levels (p=0.006). However, the period after March 2020, compared with before, saw a non-significant decrease of 1.605 units in mean 25(OH)D levels (p=0.477).

CONCLUSIONS

The study's findings indicate a significant prevalence of 25(OH)D deficiency, underscoring the necessity for preventative measures. However, the increasing trend in high 25(OH)D levels is concerning, emphasising the importance of prudent vitamin D supplement prescriptions and public education against self-medication. For efficient resource allocation and targeting of those with higher risks, it may be advantageous to concentrate vitamin D testing on specific population groups.

Prevalence and predictors of vitamin D insufficiency in Brazilian children under 5 years of age: Brazilian National Survey on Child Nutrition (ENANI-2019)

To analyse the association of socio-demographic and health factors with vitamin D insufficiency and 25-hydroxyvitamin D (25(OH)D) concentration in Brazilian children aged 6-59 months. Data from 8145 children from the Brazilian National Survey on Child Nutrition (ENANI-2019) were analysed. The serum concentration of 25(OHD)D was measured using a chemiluminescent immunoassay. The prevalence of vitamin D insufficiency (25(OH)D < 50 nmol/l) and 95 % CI was calculated. Logistic and linear regression models were used to identify the variables associated with vitamin D insufficiency and serum 25(OH)D concentrations, respectively. The mean 25(OH)D concentration was 98·6 ± 36·0 nmol/l, and 4·3 % of the children presented vitamin D insufficiency. Children aged 6-23 months (OR = 2·23; 95 % CI 1·52, 3·26); belonging to Southeast (OR = 5·55; 95 % CI 2·34, 13·17) and South (OR = 4·57; 95 % CI 1·77, 11·84) regions; the second tertile of the National Wealth Score (OR = 2·14; 95 % CI 1·16, 3·91) and winter (OR = 5·82; 95 % CI 2·67, 12·71) and spring (OR = 4·84; 95 % CI 2·17, 10·80) seasons of blood collection were associated with a higher chance of vitamin D insufficiency. Female sex (β = -5·66, 95 % CI - 7·81, -3·51), urban location (β = -14·19, 95 % CI -21·0, -7·22) and no vitamin D supplement use (β = -6·01, 95 % CI -9·64, -2·39) were inversely associated with serum 25(OH)D concentration. The age of children and the Brazilian geographical region of household location were the main predictors of vitamin D insufficiency. In Brazil, vitamin D insufficiency among children aged 6-59 months is low and is not a relevant public health problem.

Social determinants of serum 25-hydroxyvitamin D concentrations deficiency in older Chilean people

Serum 25-hydroxyvitamin D concentrations deficiency is a growing health problem that affects a significant part of the world's population, with particularly negative consequences in children and older adults. Public health has prioritized healthy aging; thus, an investigation of the social determinants related to deficient and insufficient Serum 25-hydroxyvitamin D concentrations in older adults is needed to contribute to the implementation of comprehensive social programs focused on addressing those conditions adversely affecting the health of this group. This study was conducted using a sample of older adults (age ≥ 65 years, n = 1283) from the National Health Survey (NHS 2016-2017). The Average Marginal Effects of the social determinants of Serum 25-hydroxyvitamin D concentrations deficiency in older adults were predicted using a probit model in which the outcome variable assumed two values (deficiency or not deficiency), taking as independent variables those reported in previous studies. The model showed an adequate goodness of fit, Count R2 = 0.65, and the independent variables explained between 11% (Cox-Snell) and 14% (Nagelkerke) of the variance of the outcome variable. The social determinants associated with a greater likelihood of Serum 25-hydroxyvitamin D concentrations deficiency are the following conditions: women, people of native origin, urban dwellers, shorter sunlight exposure, and greater geographical latitude. Implications are discussed, and limitations are considered. Promotion and prevention programs should preferentially target older adults in the southernmost regions who live in urban areas, with a special focus on women. Due to the country's characteristics (17°-57° south latitude), it is necessary to review in future research the three zones shown in this study as relevant social determinants for the older adults living in them to generate inputs in formulating public health policies. The authorities must define the cut-off points for considering the difference between the country's ranges of Serum 25-hydroxyvitamin D concentrations insufficiency and deficiency.

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.

Prediction of Vitamin D Deficiency in Older Adults: The Role of Machine Learning Models

CONTEXT

Conventional prediction models for vitamin D deficiency have limited accuracy.

BACKGROUND

Using cross-sectional data, we developed models based on machine learning (ML) and compared their performance with those based on a conventional approach.

METHODS

Participants were 5106 community-resident adults (50-84 years; 58% male). In the randomly sampled training set (65%), we constructed 5 ML models: lasso regression, elastic net regression, random forest, gradient boosted decision tree, and dense neural network. The reference model was a logistic regression model. Outcomes were deseasonalized serum 25-hydroxyvitamin D (25(OH)D) <50 nmol/L (yes/no) and <25 nmol/L (yes/no). In the test set (the remaining 35%), we evaluated predictive performance of each model, including area under the receiver operating characteristic curve (AUC) and net benefit (decision curves).

RESULTS

Overall, 1270 (25%) and 91 (2%) had 25(OH)D <50 and <25 nmol/L, respectively. Compared with the reference model, the ML models predicted 25(OH)D <50 nmol/L with similar accuracy. However, for prediction of 25(OH)D <25 nmol/L, all ML models had higher AUC point estimates than the reference model by up to 0.14. AUC was highest for elastic net regression (0.93; 95% CI 0.90-0.96), compared with 0.81 (95% CI 0.71-0.91) for the reference model. In the decision curve analysis, ML models mostly achieved a greater net benefit across a range of thresholds.

CONCLUSION

Compared with conventional models, ML models predicted 25(OH)D <50 nmol/L with similar accuracy but they predicted 25(OH)D <25 nmol/L with greater accuracy. The latter finding suggests a role for ML models in participant selection for vitamin D supplement trials.

High altitude Relieves transmission risks of COVID-19 through meteorological and environmental factors: Evidence from China

Existing studies reported higher altitudes reduce the COVID-19 infection rate in the United States, Colombia, and Peru. However, the underlying reasons for this phenomenon remain unclear. In this study, regression analysis and mediating effect model were used in a combination to explore the altitudes relation with the pattern of transmission under their correlation factors. The preliminary linear regression analysis indicated a negative correlation between altitudes and COVID-19 infection in China. In contrast to environmental factors from low-altitude regions (<1500 m), high-altitude regions (>1500 m) exhibited lower PM2.5, average temperature (AT), and mobility, accompanied by high SO₂ and absolute humidity (AH). Non-linear regression analysis further revealed that COVID-19 confirmed cases had a positive correlation with mobility, AH, and AT, whereas negatively correlated with SO₂, CO, and DTR. Subsequent mediating effect model with altitude-correlated factors, such as mobility, AT, AH, DTR and SO₂, suffice to discriminate the COVID-19 infection rate between low- and high-altitude regions. The mentioned evidence advance our understanding of the altitude-mediated COVID-19 transmission mechanism.

Interaction between plant-based dietary pattern and air pollution on cognitive function: a prospective cohort analysis of Chinese older adults

BACKGROUND

Air pollution is a risk factor for poor cognitive function, while a plant-based dietary pattern is associated with better cognitive function. We aimed to explore their interaction with cognitive function among older adults.

METHODS

We used a prospective cohort of old individuals, including 6525 participants of the Chinese Longitudinal Healthy Longevity Survey (CLHLS), aged 65-110 years and with normal cognition at baseline. Air pollution measurement was derived using satellite-derived annual average fine particulate matter (PM2.5) concentrations based on residential locations. Plant-based diet index (PDI) was calculated using survey responses to assess the dietary pattern. Repeated measures of the Mini-Mental State Examination (MMSE) were utilized to assess cognitive function. We applied the Cox proportional hazard regression to explore the associations and further stratified the analysis by PDI.

FINDINGS

During a median of 5·6-year follow-up, 1537 (23·6%) out of 6525 participants with normal cognition at baseline developed poor cognitive function (MMSE <18). Living in areas with the highest quintile of cumulative PM2.5 was associated with a 46% increase in the risk of developing poor cognitive function (hazard ratio (HR): 1·46, 95% confidence interval (CI): 1·20, 1·77), compared to those living in areas with the lowest quintile. We observed a significant interaction between cumulative PM2.5 and PDI (p-interaction: 0·04), with the corresponding associations of cumulative PM2.5 being more pronounced among participants with lower PDI (HR: 1·68, 95% CI: 1·26, 2·24) than those with higher PDI (HR: 1·28, 95% CI: 0·98, 1·68).

INTERPRETATION

Plant-based dietary pattern may attenuate detrimental impacts of PM2.5 on cognitive function among older adults. Adherence to the plant-based dietary pattern could be used to prevent adverse neurological effects caused by air pollution, especially in developing regions.

Genetic, sociodemographic and lifestyle factors associated with serum 25-hydroxyvitamin D concentrations in Brazilian adults: the Pró-Saúde Study

This study aims to investigate factors associated with serum 25-hydroxyvitamin D [25(OH)D] concentration in Brazilian adults considering sociodemographic and lifestyle factors, as well as vitamin D-related single nucleotide polymorphisms (SNPs). This is a cross-sectional study (n = 491; 34-79y; 251 women), nested within a prospective cohort (Pró-Saúde Study). Associations between serum 25(OH)D and sociodemographic characteristics, diet, use of supplement, physical activity, season of blood collection, body fat, skin type, sun exposure index, and SNPs CYP2R1-rs10741657 and GC-rs2282679 were explored by multiple linear regression. The prevalence of serum 25(OH)D < 50nmol/L was 55%. Serum 25(OH)D was lower among women (β = -4.38; 95%CI: -8.02; -0.74), those with higher visceral fat (β = -4.02; 95%CI: -5.92; -2.12), and those with AC and CC genotypes for GC-rs2282679 (β = -6.84; 95%CI: -10.09; -3.59; β = -10.63; 95%CI: -17.52; -3.74, respectively). Factors directly associated with serum 25(OH)D included summer (β = 20.14; 95%CI: 14.38; 25.90), intermediate skin type (β = 6.16; 95%CI: 2.52; 9.80), higher sun exposure (β = 0.49; 95%CI: 0.22; 0.75), vitamin D intake (β = 0.48; 95%CI: 0.03; 0.93), and physical activity (β = 4.65; 95%CI: 1.54; 7.76). Besides physical activity, diet, and sun exposure, non-modifiable factors, such as GC genotypes must be considered when evaluating vitamin D insufficiency in mixed-race populations. Moreover, high visceral fat in association with poorer vitamin D status deserve attention given that both conditions are unfavorably related with chronic and acute health outcomes.

High prevalence of vitamin D deficiency in Asia: A systematic review and meta-analysis

Vitamin D deficiency is a worldwide health problem. However, the prevalence of vitamin D deficiency in Asian populations is unclear. The aims of our study were to investigate the prevalence of vitamin D deficiency and its association with different health outcomes in Asia. Searches for studies published from January 2009 to January 2021 were performed in the MEDLINE (via PubMed), EMBASE, and Web of Science databases. This study was registered in the PROSPERO database (CRD42021229841). In total, 472 studies with 746,564 subjects were included in the meta-analysis. The mean serum 25-hydroxyvitamin D (25[OH]D) concentration was 49.39 nmol/L; 20.93% of the participants had 25(OH)D levels <25 nmol/L, 22.82% had levels <30 nmol/L, 57.69% had levels <50 nmol/L, and 76.85% had levels <75 nmol/L. This review found that the prevalence of vitamin D deficiency in Asia is high. The factors significantly related to vitamin D deficiency were gender, age, altitude, region, and specific diseases (diabetes, cancer, fracture, systemic lupus erythematosus [SLE], fatty liver disease, osteopenia, thyroiditis, anemia, hepatitis, metabolic diseases, and dermatitis). These findings may serve as the foundation for more detailed public health strategies and policies on this issue.

Vitamin D Status of the British African-Caribbean Residents: Analysis of the UK Biobank Cohort

The vitamin D status of the United Kingdom (UK) African-Caribbean (AC) population remains under-researched, despite an increased risk of vitamin D deficiency due to darker skin phenotypes and living at a high latitude. This cross-sectional study explored the vitamin D status and intake of AC individuals (n = 4046 with a valid serum 25(OH)D measurement) from the UK Biobank Cohort, aged ≥40 years at baseline (2006-2010). Over one third of the population were deficient (<25 nmol/L), 41.1% were insufficient (25-50 nmol/L) and 15.9% were sufficient (>50 nmol/L). Median (IQR) 25(OH)D was 30.0 (20.9) nmol/L. Logistic regression showed that brown/black skin phenotype, winter blood draw, not consuming oily fish and not using vitamin D supplements predicted increased odds of vitamin D deficiency, whilst older age and a summer or autumn blood draw were significantly associated with reduced odds of vitamin D deficiency. Vitamin D deficiency and insufficiency were prevalent in this AC population and is of considerable concern given the individual and societal implications of increased morbidity. Public health messaging for this group should focus on year-round vitamin D supplementation and increasing intakes of culturally appropriate vitamin D-rich foods. These data also support the urgent requirement for a revised vitamin D RNI for ethnic groups.

Disparities in Vitamin D Status of Newborn Infants from a Diverse Sociodemographic Population in Montreal, Canada

BACKGROUND

Vitamin D status at birth is reliant on maternal-fetal transfer of vitamin D during gestation.

OBJECTIVES

We aimed to examine the vitamin D status of newborn infants in a diverse population and to subsequently identify the modifiable correlates of vitamin D status.

METHODS

In this cross-sectional study, healthy mother-infant dyads (n = 1035) were recruited within 36 h after term delivery (March 2016-March 2019). Demographic and lifestyle factors were surveyed. Newborn serum 25-hydroxyvitamin D [25(OH)D] was measured (standardized chemiluminescence immunoassay) and categorized as deficient [serum 25(OH)D <30 nmol/L] or adequate (≥40 nmol/L). Serum 25(OH)D was compared among categories of maternal characteristics using ANOVA; each characteristic was tested in a separate model. Subgroups (use of multivitamins preconception and continued in pregnancy compared with during pregnancy only) were matched (n = 352/group) for maternal factors (ancestry, age, income, education, parity, and prepregnancy BMI) using propensity scores; logistic regression models were generated for odds of deficiency or adequacy.

RESULTS

Infants' mean serum 25(OH)D was 45.9 nmol/L (95% CI: 44.7, 47.0 nmol/L) (n = 1035), with 20.8% (95% CI: 18.3%, 23.2%) deficient and 60.7% (95% CI: 55.2%, 66.2%) adequate. Deficiency prevalence ranged from 14.6% of white infants to 41.7% of black infants. Serum 25(OH)D was higher (P < 0.0001) in infants of mothers with higher income, BMI < 25 kg/m2, exercise and sun exposure in pregnancy, and use of multivitamins preconception. In the matched-subgroup analysis, multivitamin supplementation preconception plus during pregnancy relative to only during pregnancy was associated with lower odds for vitamin D deficiency (ORadj: 0.55; 95% CI: 0.36, 0.86) and higher odds for adequate vitamin D status (ORadj: 1.47; 95% CI: 1.04, 2.07).

CONCLUSIONS

In this study most newborn infants had adequate vitamin D status, yet one-fifth were vitamin D deficient with disparities between population groups. Guidelines for a healthy pregnancy recommend maternal use of multivitamins preconception and continuing in pregnancy. An emphasis on preconception use may help to achieve adequate neonatal vitamin D status.This trial was registered at clinicaltrials.gov as NCT02563015.

Higher latitude and lower solar radiation influence on hip fracture admissions in Chilean older population

Data linking solar radiation with fractures are lacking. We found that lower solar radiation was associated with higher hip fracture admission rates in men from Chile. This supports the idea that solar radiation, a surrogate of vitamin D, may be involved in the development of fractures in older population. INTRODUCTION : To explore the associations between solar radiation and latitude with hip fracture admission rates in people aged 65 years or older in Chile, the country with the greatest variation in solar radiation in the world.

METHODS

In this ecological study, we investigated the associations between regional solar radiation and latitude with hospitalizations due to hip fracture in population aged 65 years or older, by reviewing national records between 2013 and 2018. We also evaluated the role of sociodemographic factors such as poverty, education, indigenous ethnicity, and rurality rates.

RESULTS

Between 2013 and 2018, there were 44,328 admissions due to hip fracture in people aged 65 years or older; 77.5% were women and 65.1% were aged 80 years or older. The national admission rate was 389.3 per 100,000 inhabitants (95% CI: 382.4-396.2). The highest admission rate was registered in the Region IX (445.3 per 100,000, 95% CI: 398.3-492.4), which has the highest poverty rates, indigenous ethnicity rates, and rurality rates. We found a north-south increasing gradient of admission rates in men (β=1.5 [95% CI: 0 to 3], p=0.044) and a significant association between solar radiation and admission rates in men (β=-4.4 [95% CI: -8 to 0.8], p=0.02). Admission rates in men were also associated with sociodemographic variables such as poverty (β=2.4 [95% CI: 0 to 4.8], p=0.048) and rurality rates (β=1.2 [95% CI: 0.1 to 2.4], p=0.039).

CONCLUSION

Regional solar radiation and latitude were associated with hip fracture admission rates in men aged 65 years or older in Chile, with highest admission rates at higher latitudes and lower solar radiation.

A critical update on the role of mild and serious vitamin D deficiency prevalence and the COVID-19 epidemic in Europe

Objectives

Coronavirus disease 2019 (COVID-19) has emerged as a pandemic, affecting nearly 180 million people worldwide as of June 22, 2021. Previous studies have examined the association between the mean vitamin D (Vit D) concentration of each country and COVID-19 infection and mortality rate in European countries. The aim of the present study was to critically evaluate the relationship between prevalence of mild and severe Vit D deficiency in each country and COVID-19 infection, recovery, and mortality using updated data and a different methodological approach.

Methods

Information on Vit D concentration or deficiency for each country was retrieved through a literature search. COVID-19 infections and mortalities per million people and total recoveries, as of June 22, 2021, were obtained. The associations between Vit D deficiency and COVID-19 infection, recovery, and mortality were explored using correlation coefficients and scatterplots.

Results

Non-significant correlations were observed between both number of COVID-19 infections (r = 0.363, P = 0.116) and number of recoveries (r = 0.388, P = 0.091) and the prevalence of mild Vit D deficiency (<50 nmol/L). Similarly, non-significant correlations were observed between both infections (r = 0.215, P = 0.392) and recoveries (r = 0.242, P = 0.332) and the prevalence of severe Vit D deficiency (<30 nmol/L). Significant correlations were found between COVID-19 mortality and prevalence of both mild Vit D deficiency (r = 0.634, P = 0.003) and severe Vit D deficiency (r = 0.538, P = 0.021).

Conclusions

The prevalence of neither mild nor severe Vit D deficiency was associated with the number of COVID-19 infections in European countries. Thus, it is an important parameter to consider when implementing preventive measures to face COVID-19.

Prevalence and risk factors for vitamin D deficiency in long-term childhood cancer survivors

BACKGROUND

Childhood cancer survivors (CCS) have increased risk of developing chronic health conditions, including musculoskeletal disorders. Little is known regarding vitamin D deficiency (VDD, <20 ng/ml) and its association with bone mineral density (BMD) in long-term CCS. We evaluated the prevalence and risk factors for VDD in a large, diverse population of long-term CCS, and examined the association between VDD and BMD in patients who underwent guideline-recommended dual-energy X-ray absorptiometry (DXA) screening.

METHODS

This cross-sectional study included 446 consecutive CCS seen from March 2018 to September 2020. Univariate analyses examined associations between CCS demographics, socioeconomic status, and treatment exposures and VDD. Multivariable logistic regressions identified factors associated with odds of VDD and reduced BMD.

RESULTS

Median age at evaluation was 27.5 years (range 7-67 years); median time from completing therapy was 14.2 years (range 2-65 years). Fifty percent were female, and 45% were Hispanic. Twenty-four percent had VDD. In multivariable analysis, overweight and obese BMI were associated with VDD (overweight: OR 1.78, 95% CI 1.03-3.07, p = 0.04; obese: OR 2.40, 95% CI 1.39-4.13, p < 0.01; reference: normal/underweight), as was Hispanic or black race/ethnicity (OR 2.40, 95% CI 1.41-4.09, p < 0.01; reference: non-Hispanic white). In the 118 CCS with DXA results, VDD was independently associated with reduced BMD (OR 3.58, 95%CI 1.33-9.59, p = 0.01).

CONCLUSIONS

CCS have a high prevalence of VDD. High BMI and Hispanic or black race/ethnicity were associated with VDD. Survivors with VDD had a greater than threefold risk of reduced BMD. Risk-based screening may facilitate timely interventions to mitigate VDD and improve BMD in CCS.

Early prenatal use of a multivitamin diminishes the risk for inadequate vitamin D status in pregnant women: results from the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort study

BACKGROUND

Reports on the adequacy of vitamin D status of pregnant women are not available in Canada.

OBJECTIVES

The objectives of this study were to examine vitamin D status across pregnancy and identify the correlates of vitamin D status of pregnant women in Canada.

METHODS

Pregnant women (≥18 years) from 6 provinces (2008-2011) participating in a longitudinal cohort were studied. Sociodemographic data, obstetrical histories, and dietary and supplemental vitamin D intakes were surveyed. Plasma 25-hydroxyvitamin D (25OHD) was measured using an immunoassay standardized to LC-MS/MS from samples collected during the first (n = 1905) and third trimesters (n = 1649) and at delivery (n = 1543). The proportion of women with ≥40 nmol/L of plasma 25OHD (adequate status) was estimated at each time point, and factors related to achieving this cut point were identified using repeated-measures logistic regression. Differences in 25OHD concentrations across trimesters and at delivery were tested a using repeated-measures ANOVA with a post hoc Tukey's test.

RESULTS

In the first trimester, 93.4% (95% CI: 92.3%-94.5%) of participants had 25OHD ≥40 nmol/L. The mean plasma 25OHD concentration increased from the first to the third trimester and then declined by delivery (69.8 ± 0.5 nmol/L, 78.6 ± 0.7 nmol/L, and 75.7 ± 0.7 nmol/L, respectively; P < 0.0001). A lack of multivitamin use early in pregnancy reduced the odds of achieving 25OHD ≥40 nmol/L (ORadj = 0.33; 95% CI: 0.25-0.42) across all time points. Factors associated with not using a prenatal multivitamin included multiparity (ORadj = 2.08; 95% CI: 1.42-3.02) and a below-median income (ORadj = 1.39; 95% CI: 1.02-1.89).

CONCLUSIONS

The results from this cohort demonstrate the importance of early multivitamin supplement use to achieve an adequate vitamin D status in pregnant women.

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.

The impact of micronutrient deficiency on pregnancy complications and development origin of health and disease

Due to the spread of the western style diet, which is characterized by high intake of processed food, micronutrients (vitamins and minerals) deficiency is increasing in the Japanese population of all ages and genders. During pregnancy, the elevated demand for micronutrients put pregnant women at even higher risk of micronutrients deficiency. Some micronutrients are relatively famous such that women with reproductive age are recommended to take folic acid supplementation for the prevention of neural tube defect. However, it is not generally known that folate is also important for fetal growth throughout the pregnancy course and for prevention of pregnancy complications, and that pregnant women should continue to take supplementation during pregnancy and lactation. The types of micronutrients and the duration of supplementation are both important factors to maintain normal pregnancies. This review focused on four micronutrients that are commonly deficient in Japanese pregnant women, folate, vitamin B12, vitamin D, calcium, and magnesium. The detrimental effects of homocysteine accumulation associated with the above micronutrient defects and its link to catechol-o-methyltransferase insufficiency are described. We also discussed possible molecular mechanisms of pregnancy complications and the development origin of health and disease (DOHaD) regarding micronutrient deficiencies from the point of view of one carbon metabolism.

Physical Determinants of Vitamin D Photosynthesis: A Review

Vitamin D synthesis by exposure of skin to solar ultraviolet radiation (UVR) provides the majority of this hormone that is essential for bone development and maintenance but may be important for many other health outcomes. This process, which is the only well-established benefit of solar UVR exposure, depends on many factors including genetics, age, health, and behavior. However, the most important factor is the quantity and quality of UVR reaching the skin. Vitamin D synthesis specifically requires ultraviolet B (UVB) radiation that is the minority component (<5%) of solar UVR. This waveband is also the most important for the adverse effects of solar exposure. The most obvious of which is sunburn (erythema), but UVB is also the main cause of DNA damage to the skin that is a prerequisite for most skin cancers. UVB at the Earth's surface depends on many physical and temporal factors such as latitude, altitude, season, and weather. Personal, cultural, and behavioral factors are also important. These include skin melanin, clothing, body surface area exposed, holiday habits, and sunscreen use. There is considerable disagreement in the literature about the role of some of these factors, possibly because some studies have been done by researchers with little understanding of photobiology. It can be argued that vitamin D supplementation obviates the need for solar exposure, but many studies have shown little benefit from this approach for a wide range of health outcomes. There is also increasing evidence that such exposure offers health benefits independently of vitamin D: the most important of which is blood-pressure reduction. In any case, public health advice must optimize risk versus benefit for solar exposure. It is fortunate that the individual UVB doses necessary for maintaining optimal vitamin D status are lower than those for sunburn, irrespective of skin melanin. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Vitamin D supplementation: position Statement of the Iberoamerican Society of Osteoporosis and Mineral Metabolism (SIBOMM)

BACKGROUND

Vitamin D (VD) deficiency is a global pandemic that affects more than a third of the population worldwide. The population of Latin America and the Caribbean exceeds 620 million inhabitants with diverse ethnic origins and different latitudes and altitudes, which make comparisons and generalizations difficult.

AIM AND METHOD

We sought to establish an expert consensus regarding the recommendations for VD supplementation in Latin America by means of the Delphi methodology.

RESULTS

The prophylactic dosage of VD in the general population should be individualized according to age, race, body weight, sun exposure of an individual, altitude, and dietary and exercise habits, without ruling out existing chronic diseases.

CONCLUSION

The importance of VD has been widely documented and its deficiency is a pandemic. Many individuals have difficulty meeting daily VD requirements through food and the sun. The population of Latin America and the Caribbean has diverse ethnics, cultures, in addition to living in different latitudes and altitudes. Therefore, it is important to make a position on VD supplementation, given the different characteristics, ages and serum levels of 25(OH)D.

Exploring the Impact of Individual UVB Radiation Levels on Serum 25-Hydroxyvitamin D in Women Living in High Versus Low Latitudes: A Cross-Sectional Analysis from the D-SOL Study

Vitamin D can be synthesized in the skin via sunlight exposure as well as ingested through diet. Vitamin D deficiency is currently a major global public health issue, with increasing prevalence in both low and high latitude locations. This cross-sectional analysis aimed to compare the intensity of individual Ultraviolet B radiation levels between women of the same ethnicity living in England and Brazil, respectively; and to investigate the association with circulating 25(OH)D concentrations. We analysed data from 135 Brazilian women (England, n = 56, 51° N; Brazil, n = 79, 16° S) recruited for the D-SOL study (Interaction between Vitamin D Supplementation and Sunlight Exposure in Women Living in Opposite Latitudes). Serum 25(OH)D concentrations were analysed by high performance liquid chromatography tandem mass spectrometry (HPLC-MS), individual UVB radiation via UVB dosimeter badges and dietary intake via 4-day diet diaries. Anthropometric, skin phototype, sociodemographic and lifestyle patterns were also assessed. Mean serum 25(OH)D concentration of England residents was significantly lower than Brazil residents. Daily individual UVB radiation level showed a strong significant positive correlation with serum 25(OH)D concentrations. The required UVB radiation to achieve 75 nmol/L was 2.2 SED and 38.8% of the total variance in 25(OH)D concentrations was explained uniquely by daily individual UVB radiation, after controlling for the influence of age and body mass index. Thus, these results highlight the strong positive association between serum 25(OH)D concentrations and individual UVB radiation and the influence of different individual characteristics and behaviours. Collectively, these factors contribute to meaningful, country-specific, public health strategies and policies for the efficient prevention and treatment of vitamin D inadequacy.

Effects of sulfur dioxide, ozone, and ambient air pollution on bone metabolism related biochemical parameters in a rat model

Ambient air pollution (AAP), as an important environmental health problem, affects everyone. A large body of literature links AAP, such as sulfur dioxide (SO2) and ozone (O3), with a wide range of non-communicable diseases. The aim of the present study was to investigate the effects of the pollutants on the bone metabolism biochemical parameters in a rat model. Thirty-two male Wistar rats were divided to four groups: control, SO2 (10 ppm), O3 (0.6 ppm), and AAP groups. After 5 weeks of exposure (3 hours/day, 6 days/week), blood samples were taken, and biochemical parameters were assayed. Vitamin D level of the AAP group was higher than the control and SO2 groups (p=0.004 and 0.003). Parathyroid hormone (PTH) level of the O3 group was significantly higher than the AAP group (p=0.006). Alkaline phosphatase (ALP), phosphorus, magnesium levels of the SO2 group; Vit D, ALP, osteocalcin (OC), and PTH of O3 group; and OC and osteoprotegerin (OPG) of AAP group were higher than those of control group but differences were not significant. Calcium level of the SO2 group; OPG and calcium of O3 group; and PTH of AAP group were less than those of control group but differences were not significant (p>0.05). The results showed significant effect of AAP with natural daylight on vitamin D and also O3 on PTH of the rats. In the concentrations and conditions of the study, we didn't find any significant unwanted effects of AAP, SO2, and O3 on the bone biochemical parameters. More investigations with more concentrations and exposure time are recommended.

High altitude reduces infection rate of COVID-19 but not case-fatality rate

Coronavirus disease 19 (COVID-19) is a pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). It is suggested that life at high altitude may reduce COVID-19 infections and case-fatality rates (cases/deaths). We study data from Peru COVID-19 pandemics, which first case was recorded on March 6th, 2020. By June 13, 2020 there were 6498 deaths, and 224,132 SARS-CoV-2 positives. Using data from 185 capitals of provinces with altitudes ranging from 3 to 4342 m, we confirm previous reports that infection with COVID-19 at high altitude is reduced. However, case-fatality rate is not dependent of altitude. We have also presented first evidence that female protection towards death by COVID-19 is reduced as altitude of residence increases.

Barriers towards Sun Exposure and Strategies to Overcome These Barriers in Female Indoor Workers with Insufficient Vitamin D: A Qualitative Approach

The prevalence of vitamin D insufficiency is significant even in tropical countries such as Malaysia. Sun exposure is the primary source of vitamin D for most people due to limited intakes of food containing vitamin D and supplements. This study explored the perception of barriers towards sun exposure and strategies to overcome these barriers among vitamin D insufficient women workers in Kuala Lumpur, Malaysia. Twenty-five female indoor workers with serum 25-hydroxyvitamin D < 50 nmol/L participated in seven focus group discussions (FGDs). Barriers towards sun exposure were lack of accurate knowledge of vitamin D, health concern towards sun exposure, time constraints, desire to have fair and beautiful skin, sedentary lifestyle, indoor workplace, weather, lack of social support, living arrangement, safety concerns, and religious or cultural practices. The improvement strategies were classified into lifestyle changes and workplace opportunity for sun exposure. Public education on safe sun exposure to produce an optimal level of vitamin D is necessary. Future studies should evaluate the effectiveness of sunlight exposure program at workplace for the high-risk vitamin D deficiency group.

Vitamin D concentration and psychotic disorder: associations with disease status, clinical variables and urbanicity

BACKGROUND

The association between schizophrenia and decreased vitamin D levels is well documented. Low maternal and postnatal vitamin D levels suggest a possible etiological mechanism. Alternatively, vitamin D deficiency in patients with schizophrenia is presumably (also) the result of disease-related factors or demographic risk factors such as urbanicity.

METHODS

In a study population of 347 patients with psychotic disorder and 282 controls, group differences in vitamin D concentration were examined. Within the patient group, associations between vitamin D, symptom levels and clinical variables were analyzed. Group × urbanicity interactions in the model of vitamin D concentration were examined. Both current urbanicity and urbanicity at birth were assessed.

RESULTS

Vitamin D concentrations were significantly lower in patients (B = -8.05; 95% confidence interval (CI) -13.68 to -2.42; p = 0.005). In patients, higher vitamin D concentration was associated with lower positive (B = -0.02; 95% CI -0.04 to 0.00; p = 0.049) and negative symptom levels (B = -0.03; 95% CI -0.05 to -0.01; p = 0.008). Group differences were moderated by urbanicity at birth (χ2 = 6.76 and p = 0.001), but not by current urbanicity (χ2 = 1.50 and p = 0.224). Urbanicity at birth was negatively associated with vitamin D concentration in patients (B = -5.11; 95% CI -9.41 to -0.81; p = 0.020), but not in controls (B = 0.72; 95% CI -4.02 to 5.46; p = 0.765).

CONCLUSIONS

Lower vitamin D levels in patients with psychotic disorder may in part reflect the effect of psychosis risk mediated by early environmental adversity. The data also suggest that lower vitamin D and psychopathology may be related through direct or indirect mechanisms.

Does Vitamin D play a role in the management of Covid-19 in Brazil?

The study discusses the possible role of adequate vitamin D status in plasma or serum for preventing acute respiratory infections during the Covid-19 pandemic. Our arguments respond to an article, published in Italy, that describes the high prevalence of hypovitaminosis D in older Italian women and raises the possible preventive and therapeutic role of optimal vitamin D levels. Based on literature review, we highlight the findings regarding the protective role of vitamin D for infectious diseases of the respiratory system. However, randomized controlled trials are currently lacking. Adequate vitamin D status is obtained from sun exposure and foods rich in vitamin D. Studies in Brazil have shown that hypovitaminosis D is quite common in spite of high insolation. Authors recommend ecological, epidemiological and randomized controlled trials studies to verify this hypothesis.

Avoidance of vitamin D deficiency to slow the COVID-19 pandemic

Vitamin D deficiency, which impedes good immune function, is common during winter and spring in regions of high latitude. There is good evidence that vitamin D deficiency contributes to the seasonal increase of virus infections of the respiratory tract, from the common cold to influenza, and now possibly also COVID-19. This communication explores key factors that make it more likely, particularly in combination, that individuals are vitamin D deficient. These factors include old age, obesity, dark skin tone and common genetic variants that impede vitamin D status. Precision nutrition is an approach that aims to consider known personal risk factors and health circumstances to provide more effective nutrition guidance in health and disease. In regard to avoiding vitamin D deficiency, people with excess body fat, a dark skin tone or older age usually need to use a moderately dosed daily vitamin D supplement, particularly those living in a high-latitude region, getting little ultraviolet B exposure due to air pollution or staying mostly indoors. Carriers of the GC (group-specific component) rs4588 AA genotype also are more likely to become deficient. Very high-dosed supplements with more than 4000 IU vitamin D are rarely needed or justified. A state-by-state Mendelian randomisation analysis of excess COVID-19 mortality of African-Americans in the USA shows a greater disparity in northern states than in southern states. It is conceivable that vitamin D adequacy denies the virus easy footholds and thereby slows spreading of the contagion. This finding should drive home the message that vitamin D supplementation is particularly important for individuals with dark skin tones. Vitamin D deficiency, even for a few months during the winter and spring season, must be rigorously remedied because of its many adverse health impacts that include decreased life expectancy and increased mortality. Slowing the spread of COVID-19 would be an added bonus.

The Role of Daylight for Humans: Gaps in Current Knowledge

Daylight stems solely from direct, scattered and reflected sunlight, and undergoes dynamic changes in irradiance and spectral power composition due to latitude, time of day, time of year and the nature of the physical environment (reflections, buildings and vegetation). Humans and their ancestors evolved under these natural day/night cycles over millions of years. Electric light, a relatively recent invention, interacts and competes with the natural light-dark cycle to impact human biology. What are the consequences of living in industrialised urban areas with much less daylight and more use of electric light, throughout the day (and at night), on general health and quality of life? In this workshop report, we have classified key gaps of knowledge in daylight research into three main groups: (I) uncertainty as to daylight quantity and quality needed for "optimal" physiological and psychological functioning, (II) lack of consensus on practical measurement and assessment methods and tools for monitoring real (day) light exposure across multiple time scales, and (III) insufficient integration and exchange of daylight knowledge bases from different disciplines. Crucial short and long-term objectives to fill these gaps are proposed.

Factors Influencing Vitamin D Levels in Neonatal Umbilical Cord Blood: A Two-Center Study From Tibet and Shenyang

Objective: To investigate the factors influencing the levels of vitamin D (vitD) in the umbilical cord blood of neonates born in Naqu, Tibet (4,500 m above sea level), and Shenyang, Liaoning Province (500 m above sea level). Methods: This prospective study was conducted from June 2017 to October 2018 in Naqu (the plateau group) and Shenyang, (the non-plateau group). Healthy mothers that gave birth to healthy neonates of >2,000g after 38 weeks' gestation were enrolled in the study, as were their neonates. After separation of serum from the umbilical cord and mothers for routine biochemical tests, discarded samples were remained for analyses of vitD, calcium, phosphorus, alkaline phosphatase (ALP) and parathyroid hormone (PTH). Questionnaires were developed covering the demographic characteristics and possible risk factors for neonatal vitD deficiency of mothers. Statistical analysis was performed to identify associations between the calcium, phosphorus, ALP, PTH, maternal factors and neonatal vitD levels. Results: In total, 295 neonates and 225 mothers were enrolled in the study. VitD deficiency was common in neonates and mothers. The risk of vitD deficiency was higher in the plateau group than in the non-plateau group. The mean levels of 25-hydroxy vitD (25(OH)D) in mothers and neonates from the plateau group were 8.49 ± 4.12 ng/mL and 10.17 ± 5.07 ng/mL, respectively. Such levels were significantly lower than those in the non-plateau group (19.77 ± 9.57 ng/mL and 23.93 ± 11.01 ng/mL, respectively). The vitD levels of neonates and mothers were highest in the summer and lowest in the winter. Cord blood vitD was positively correlated with the vitD levels in mothers' serum (r = 0.75, P < 0.05). Increased PTH levels in mothers and decreased cord blood calcium levels were risk factors for neonatal vitD deficiency. A lack of vitD supplementation during pregnancy was associated with an 8.91-fold higher probability of neonatal vitD deficiency (OR = 8.91, 95% CI = 1.521-9.429, P < 0.001). Conclusions: The levels of neonatal and maternal vitD in the plateau group were generally lower than those in the non-plateau group. VitD supplementation during pregnancy could effectively reduce the risk of vitD deficiency in neonates.

Vitamin D and nonalcoholic fatty liver disease

PURPOSE OF REVIEW

Vitamin D deficiency may impact disease progression of nonalcoholic fatty liver disease (NAFLD). The aim of this work was to review recent studies examining either vitamin D status or the effects of supplementation in patients with NAFLD, along with investigating the roles of genetic polymorphisms and the gut microbiome.

RECENT FINDINGS

Six heterogeneous observational studies of vitamin D status, and four randomized controlled intervention trials of vitamin D supplementation in NAFLD were conflicting. All studies were hampered by the challenges of diagnosing NAFLD, were underpowered, and lacked data on clinically important outcomes. The results of three cross-sectional studies, including a Mendelian randomization study, provide limited evidence for a role for genetic modifiers of vitamin D status in NAFLD. Genetic and experimental evidence suggests that vitamin D and the vitamin D receptor (VDR) may influence the gut microbiome in health and disease.

SUMMARY

The evidence relating either lower vitamin D status to the prevalence and severity of NAFLD, or examining vitamin D supplementation in patients with NAFLD is inconclusive. Larger, higher quality trials with relevant endpoints are needed. Further mechanistic studies on the roles of vitamin D and VDR in influencing the gut-liver axis in NAFLD are warranted.

The Role of Skeletal Muscle in Maintaining Vitamin D Status in Winter

The status of vitamin D is determined mainly by its formation in skin by the photochemical action of solar UVB light (wavelength 290-320 nm) on the precursor 7-dehydrocholesterol. Because of seasonal variation in intensity of solar UV light, vitamin D status falls in winter and rises in summer. It has been presumed that there is no functional store of vitamin D. Thus, to avoid deficiency, a nutritional supply would be required in winter. However, there is now evidence that the main circulating metabolite of vitamin D, 25-hydroxyvitamin D, accumulates in skeletal muscle cells, which provide a functional store during the winter months. The mechanism is mediated by muscle cell uptake of circulating vitamin D-binding protein (DBP) through a megalin-cubilin membrane transport process. DBP then binds to cytoplasmic actin to provide an array of high-affinity binding sites for 25-hydroxyvitamin D [25(OH)D]. The repeated passage of 25(OH)D into and out of muscle cells would account for its long residence time in blood.

Association between solar ultraviolet doses and vitamin D clinical routine data in European mid-latitude population between 2006 and 2018

The major source of vitamin D in humans is the ultraviolet radiation-dependent cutaneous synthesis of cholecalciferol; however, low vitamin D status is common in Europe even at mid-latitudes. The UV-radiation that reached the Earth's surface near Milan between May 2006 and December 2018 was retrieved from the TEMIS database and matched with the serum vitamin D levels measured in 30 400 people living in the same area. The results showed a high percentage of insufficient vitamin D levels (measured as 25-hydroxy-vitamin D) throughout the years. During the "vitamin D winter" (November-March) up to 60-90% of the population shows deficient/insufficient (<20-30 ng mL^-1) levels of vitamin D and it is explained by the difficulty in obtaining the recommended UV vitamin D doses. In contrast, the warm season provides plenty of UV-radiation, but still 30-50% of the population shows deficient/insufficient vitamin D levels. The circannual vitamin D variations were less evident in the female groups which, in the cold season, show values higher than the corresponding male groups. An age group analysis explained this difference by the strongly recommended vitamin D intake for post-menopausal women. In conclusion, increasing the medical advice for vitamin D intake is strongly recommended to improve the vitamin D status at European mid-latitudes. Our findings suggest that UV availability alone cannot explain the vitamin D status of the population which instead is likely to be influenced by several other factors related to both the people's lifestyle and their personal characteristics. A desirable vitamin D range considering the time of the year and sun exposure, but also including factors not related to UV-radiation, would probably result in a more accurate diagnosis of the patients' vitamin D status. Despite the relatively large time interval, no evident effects due to climate changes were observed in the vitamin D levels during the almost 13 years of analysis.

VDR rs2228570 Polymorphism Is Related to Non-Progression to AIDS in Antiretroviral Therapy Naïve HIV-Infected Patients

Background: Vitamin D is a fundamental regulator of host defenses by activating genes related to innate and adaptive immunity. In this study, we analyzed the association among single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene, with clinical patterns of AIDS progression in antiretroviral treatment (ART)-naïve HIV-infected patients. Methods: We conducted a retrospective study in 667 HIV-infected patients, who were classified within three groups according to their AIDS progression pattern (183 long-term non-progressors (LTNPs), 334 moderate progressors (MPs), and 150 rapid progressors (RPs)). Five VDR SNPs (rs11568820, rs4516035, rs2228570, rs1544410, and rs7975232) were genotyped using Agena Bioscience’s MassARRAY platform. Results: Significant association results were found for rs2228570. Within all HIV patients, the presence of T allele at VDR rs2228570 SNP was protective against AIDS progression (ordinal outcome) under additive (adjusted odds ratio (aOR) = 0.75; p = 0.009), dominant (aOR = 0.69; p = 0.015), and codominant (aOR = 0.56; p = 0.017) inheritance models. In addition, the same allele was protective under additive and codominant inheritance models when we compared with LTNPs vs. RPs [aOR = 0.64 (p = 0.019) and aOR = 0.37 (p = 0.018), respectively] and when we compared MPs vs. RPs [aOR = 0.72 (p = 0.035) and aOR = 0.45 (p = 0.028), respectively]. Conclusions: The VDR rs2228570 T allele was related to a lower AIDS progression pattern in ART-naïve HIV-infected patients. These findings expand upon the knowledge about HIV pathogenesis in untreated HIV-infected patients with different clinical outcomes.