Adherence to Vitamin D Supplementation Recommendations for Breastfed Infants and Young Children: An Analysis of Canadian Community Health Survey Data Cycles From 2015 to 2018.

BACKGROUND: In Canada, nutrition policy, as outlined in the Nutrition for Healthy Term Infants recommendations, includes a daily vitamin D supplement of 10 µg (400 IU) for breastfed infants and young children to support adequate vitamin D status. OBJECTIVES: This study aimed to report on adherence to vitamin D supplementation recommendations for breastfed infants (≤12 months); and for children breastfed >12 mo. METHODS: Canadian Community Health Survey (paired-cycles 2015/2016 and 2017/2018) maternal experiences data for infants born 2012-2018 who received any breastmilk formed the sample (n = 7079). Whether the infant was given a vitamin D supplement (yes/no) and the frequency (daily/almost every day, 1-2/wk, or <1/wk) were surveyed. Weighted data (95% CI) were summarized according to breastfeeding history (exclusive to 6 mo and continuing; partial to 6 mo and continuing; and stopped ≤6 mo). Correlates of supplement adherence were explored using logistic regression. RESULTS: Overall, 87.1% (95% CI: 85.9%, 88.3%) of participants reported giving their infant (≤12 mo) a vitamin D supplement, and of these, 83.3% (95% CI: 81.9%, 84.7%) did so daily/almost every day, 12.4% (95% CI: 11.1%, 13.7%) did so 1-2/wk, and 4.3% (95% CI: 3.6%, 5.0%) did so <1/wk. Lower adjusted odds of adherence were observed among participants reporting: stopped breastfeeding ≤6 mo, lower education or income, recent immigration, and overweight prepregnancy body mass index; higher odds of adherence were observed in the western provinces. Regarding mothers of children >12 mo and breastfed (n = 2312), 58.0% (95% CI: 54.9%, 61.1%) gave a vitamin D supplement daily/almost every day. CONCLUSIONS: Adherence to providing a vitamin D supplement to breastfed infants is high in Canada. Nonetheless, we estimate that ∼27% of mothers are nonadherent to daily/almost every day administration of a vitamin D supplement and that adherence declines in children breastfed >12 mo. Further promotion to support uptake of the current guidance may be necessary, particularly for parents of recent immigration or lower socioeconomic status.

Vitamin D fortification of foods - sensory, acceptability, cost, and public acceptance considerations.

In terms of vitamin D food fortification, there are a number of important considerations in relation to selection of the food vehicle and fortificant. While there has been much research focus on the ability of fortified foods to improve vitamin D status, other considerations, such as sensory properties and acceptability, cost, and public attitudes around vitamin D-fortified foods, have received less attention. Thus, the present narrative review aimed to summarize the existing knowledge around these important considerations. In summary, its findings suggest that: i) vitamin D addition to various food vehicles, at levels consistent with the supply of part or all the recommended intake, does not alter their sensory characteristics or overall acceptability; ii) overall, vitamin D fortification of foods is relatively cost-effective, despite the fact that some attitudinal studies highlighted participant concerns about the potential cost/expense of vitamin D-fortified foods; iii) evidence from various attitudinal studies suggest a high level of acceptance and/or purchase intention (i.e., extent to which customers are willing and inclined to buy) of vitamin D-fortified food products by the general public; and iv) there have been repeated calls for vitamin D public health educational/information campaigns to help educate consumers about the health risks associated with vitamin D deficiency and nutritional benefits associated with consumption of vitamin D-fortified foods. Such campaigns could positively mediate attitudes and acceptance of vitamin D-fortified foods amongst the public, and could also help address misconceptions and allay fears around vitamin D for concerned individuals. Lastly, the findings of the present review also highlight the existence of between-country differences, even within Europe, in relation to attitudes and purchase intention of vitamin D-fortified foods and the perceived appropriateness of certain food vehicles for vitamin D fortification, as well as the best mix of communication channels for a vitamin D public health educational/information campaign.

Balancing the risks and benefits of sun exposure: A revised position statement for Australian adults.

OBJECTIVE: To describe the development of a new position statement regarding balancing the risks and benefits of sun exposure for Australian adults. METHODS: We conducted a Sun Exposure Summit in March 2021, with presentations from invited experts and a workshop including representation from academic, clinical, policy, and patient stakeholder organisations. The group considered advice about balancing the risks and benefits of sun exposure for Australian adults and developed a revised consensus position statement. RESULTS: The balance of risks and benefits of sun exposure is not the same for everybody. For people at very high risk of skin cancer, the risks of exposure likely outweigh the benefits; sun protection is essential. Conversely, people with deeply pigmented skin are at low risk of skin cancer but at high risk of vitamin D deficiency; routine sun protection is not recommended. For those at intermediate risk of skin cancer, sun protection remains a priority, but individuals may obtain sufficient sun exposure to maintain adequate vitamin D status. CONCLUSIONS: The new position statement provides sun exposure advice that explicitly recognises the differing needs of Australia's diverse population. IMPLICATIONS FOR PUBLIC HEALTH: Mass communication campaigns should retain the focus on skin cancer prevention. The new position statement will support the delivery of personalised advice.

Vitamin D Supplementation: A Review of the Evidence Arguing for a Daily Dose of 2000 International Units (50 µg) of Vitamin D for Adults in the General Population.

Vitamin D deficiency is considered a public health problem due to its worldwide high prevalence and adverse clinical consequences regarding musculoskeletal health. In addition, vitamin D may also be crucial for the prevention of certain extraskeletal diseases. Despite decades of intensive scientific research, several knowledge gaps remain regarding the precise definition of vitamin D deficiency and sufficiency, the health benefits of improving vitamin D status, and the required vitamin D intakes. Consequently, various societies and expert groups have released heterogeneous recommendations on the dosages for vitamin D supplementation. In this brief narrative review, we outline and discuss recent advances regarding the scientific evidence arguing for a daily vitamin D supplementation with 2000 international units (IU) (50 µg) of vitamin D3 to prevent and treat vitamin D deficiency. According to data from randomized controlled trials (RCTs), such a dose may improve some health outcomes and is sufficient to raise and maintain serum 25(OH)D concentrations above 50 nmol/L (20 ng/mL) and above 75 nmol/L (30 ng/mL) in >99% and >90% of the general adult population, respectively. According to large vitamin D RCTs, there are no significant safety concerns in supplementing such a dose for several years, even in individuals with an already sufficient vitamin D status at baseline. A daily vitamin D supplementation with 2000 IU (50 µg) may be considered a simple, effective, and safe dosage to prevent and treat vitamin D deficiency in the adult general population.

The associations of serum vitamin D status and vitamin D supplements use with all-cause dementia, Alzheimer's disease, and vascular dementia: a UK Biobank based prospective cohort study.

BACKGROUND: Prior studies on vitamin D and dementia outcomes yielded mixed results and had several important limitations. OBJECTIVES: We aimed to assess the associations of both serum vitamin D status and supplementation with all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VD) incidence. METHODS: With a prospective cohort study design, we comprehensively assessed the associations of vitamin D and multivitamin supplementation, as well as vitamin D deficiency {25-hydroxyvitamin D [25(OH)D] <30 nmol/L}, and insufficiency [25(OH)D 30 to <50 nmol/L], with the 14-year incidence of all-cause dementia, AD, and VD in 269,229 participants, aged 55 to 69, from the UK Biobank. RESULTS: Although 5.0% reported regular vitamin D use and 19.8% reported multivitamin use, the majority of participants exhibited either vitamin D deficiency (18.3%) or insufficiency (34.0%). However, vitamin D deficiency was less prevalent among users of vitamin D (6.9%) or multivitamin preparations (9.5%) than among nonusers (21.5%). Adjusted Cox regression models demonstrated 19% to 25% increased risk of all 3 dementia outcomes for those with vitamin D deficiency [hazard ratio (HR) 95% confidence interval (CI)]: 1.25 (1.16, 1.34) for all-cause dementia; 1.19 (1.07-1.31) for AD; 1.24 (1.08-1.43) for VD] and 10% to 15% increased risk of those with vitamin D insufficiency [HR (95% CI): 1.11 (1.05, 1.18) for all-cause dementia; 1.10 (1.02-1.19) for AD; 1.15 (1.03-1.29) for VD]. Regular users of vitamin D and multivitamins had 17% and 14% lower risk of AD [HR (95% CI): 0.83 (0.71, 0.98)] and VD [HR (95% CI): 0.86 (0.75, 0.98)] incidence, respectively. CONCLUSIONS: Although our findings indicate the potential benefits of vitamin D supplementation for dementia prevention, randomized controlled trials are essential for definitive evidence.

Vitamin D Status among Patients Admitted to a Geriatric Ward-Are Recommendations for Preventing Its Deficiency Effective Enough?

Despite a decade of available recommendations aimed at preventing vitamin D (VD) deficiency in Poland, the efficacy of these measures among community-dwelling older individuals remains inconsistent. The PolSenior2 study provided valuable insights into VD status among community-dwelling older individuals in Poland. However, it is important to note that this research did not include the elderly living in care institutions. Therefore, our study concentrates on evaluating VD status in older patients admitted to a geriatrics ward to indirectly assess their adherence to existing recommendations and preventive actions in this particular setting (whether they translate into health-promoting behaviors (i.e., taking vitamin D supplements) and whether the recommended, optimal 25(OH)D concentration values are achieved). This approach offers a comprehensive understanding of VD status in a previously understudied population. We aimed to evaluate VD status in patients aged 70 and above within the geriatrics ward, exploring its association with age, sex, BMI, and the use of VD supplements. The study involved the measurement of serum VD concentration in 240 individuals. Of these participants, 177 (73.8%) were women, and 193 (80.4%) were over 75 years old. The median 25(OH)D concentration was found to be 22.95 (IQR, 13.7-33.0) ng/mL. Notably, profound deficiency (<10 ng/mL) was noted in 15% of the participants, while 67.5% exhibited VD inadequacy (<30 ng/mL). It is worth mentioning that only 18.3% of individuals took VD supplements preadmission. Insufficiency was more prevalent in nonsupplemented individuals (70.9% vs. 52.3%, p = 0.02) and those with a BMI ≥30 kg/m2 (76.2% vs. 59.2%, p = 0.007). The logistic regression model demonstrated that obese patients had over two times higher odds of VD inadequacy (OR = 2.21, p = 0.0074), as did nonsupplemented individuals (OR = 2.23, p = 0.0187). The high prevalence of VD deficiency and inadequacy in geriatric ward admissions emphasizes the urgent need for targeted interventions and enhanced education for older adults, caregivers, and physicians to improve adherence to preventive supplementation practices.

Prospective cohort study of vitamin D deficiency in pregnancy: Prevalence and limited effectiveness of 1000 IU vitamin D supplementation.

BACKGROUND: Vitamin D deficiency is highly prevalent worldwide among pregnant women. Although vitamin D supplementation is effective in improving vitamin D status, the safety and optimal dosing of vitamin D supplementation during pregnancy remain less well understood. OBJECTIVE: This study aimed to investigate the prevalence of vitamin D deficiency among pregnant women and evaluate the effectiveness of vitamin D supplementation in improving vitamin D status during pregnancy. DESIGN: This prospective cohort study assessed the impact of a 16-week daily vitamin D supplementation 1000 IU regimen on vitamin D status among pregnant women. METHODS: A total of 365 pregnant women were recruited, and their baseline total circulating 25-hydroxy vitamin D concentrations were measured. Of these, 249 participants completed the study, which involved oral daily supplementation with 1000 IU of vitamin D and a repeat of total circulating 25-hydroxy vitamin D concentrations after 16 weeks. RESULTS: The study found that 57.7% of the participants had vitamin D deficiency, consistent with the rates reported in other studies. However, vitamin D supplementation at a dose of 1000 IU had a small effect size and was not clinically significant. However, 67% of participants with vitamin D deficiency remained deficient; among participants initially with vitamin D insufficiency, 30% became deficient. Moreover, 26.5% of individuals with sufficient vitamin D status at 12 weeks showed insufficient levels by 28 weeks. CONCLUSION: Vitamin D deficiency is widespread among pregnant women, and vitamin D supplementation at a daily dose of 1000 IU may not adequately address this problem. Although the study has limitations, its results align with previous research and may apply to other populations with a high prevalence of vitamin D deficiency during pregnancy. Further research is necessary to determine the most effective approach for addressing prenatal vitamin D deficiency.

Prevalence and effectiveness of vitamin D supplementation during pregnancyVitamin D deficiency is common among pregnant women and can lead to various health issues. This study aimed to investigate the effectiveness of vitamin D supplementation in improving vitamin D levels during pregnancy. A total of 365 pregnant women were recruited, and their vitamin D levels were measured at the beginning of the study. The participants were given a daily vitamin D supplement of 1000 IU, and their vitamin D levels were measured at 3-month intervals. The study found that more than half of the participants had vitamin D deficiency, which is consistent with the rates reported in other studies. However, vitamin D supplementation at the given dosage had a small effect and did not significantly increase vitamin D levels in pregnant women. Moreover, vitamin D-rich diets had no significant impact on vitamin D levels. The study emphasizes the importance of identifying effective strategies for preventing and treating vitamin D deficiency during pregnancy. The findings suggest that current strategies advised by international and national guidelines may not be sufficient to address the problem. Further research is needed to identify more effective approaches, including screening, higher safe dosages, and monitoring responses after 3 months of treatment. In summary, vitamin D deficiency is common among pregnant women, and current strategies may not be enough to address the issue. The study highlights the need for effective approaches to prevent and treat vitamin D deficiency during pregnancy, and further research is needed to find these strategies.

Adherence to vitamin D supplementation guidelines in children under five years of age: a systematic literature review.

PURPOSE: Despite the presence of guidelines on vitamin D supplementation in infants and young children, little is known about parental adherence to their recommendations. This review aims to summarise the evidence from observational studies investigating adherence to vitamin D supplementation guidelines in children under five years of age. METHODS: Databases of PubMed, Scopus, Web of Science, and CINAHL were searched from January 2000 until July 2022. Qualitative data synthesis was used to summarise evidence on supplementation adherence. The adherence rate was categorised as low, moderate, and high if it was ≤ 50%, between 50 and 70%, and ≥ 70%, respectively. RESULTS: Eleven studies investigating adherence to eight different vitamin D supplementation guidelines from European countries, USA and Canada were included. The majority of studies were cross-sectional and conducted among infants. Overall, the adherence rate ranged between 14.29% and 95.6%. Low, moderate, and high adherence to supplementation guidelines were reported in six, three, and two studies, respectively. CONCLUSION: There is generally poor adherence to vitamin D supplementation guidelines in children under five years of age. Nevertheless, the evidence comes from a limited number of studies, mainly conducted in infants, with high methodological heterogeneity in terms of the vitamin D supplementation guideline assessed and the definition of supplementation adherence in the study population. Further research is warranted to identify effective health promotion interventions to increase supplementation adherence and reduce the risk of vitamin D deficiency at this critical life stage.

Comparison of the Effect of Daily Vitamin D2 and Vitamin D3 Supplementation on Serum 25-Hydroxyvitamin D Concentration (Total 25(OH)D, 25(OH)D2, and 25(OH)D3) and Importance of Body Mass Index: A Systematic Review and Meta-Analysis.

BACKGROUND: Two previous meta-analyses showed smaller differences between vitamin D3 and vitamin D2 in raising serum 25-hydroxyvitamin D [25(OH)D] and a consistently high heterogeneity when only including daily dosing studies. OBJECTIVE: This study aimed to compare more frequently dosed vitamin D2 and vitamin D3 in improving total 25(OH)D and determine the concomitant effect of response modifiers on heterogeneity, and secondly, to compare the vitamin D2-associated change in 25(OH)D2 with the vitamin D3-associated change in 25(OH)D3. METHODS: PubMed, EMBASE, Cochrane, and the Web of Science Core collection were searched for randomized controlled trials of vitamin D2 compared with vitamin D3, daily or once/twice weekly dosed. After screening for eligibility, relevant data were extracted for meta-analyses to determine the standardized mean difference when different methods of 25(OH)D analyses were used. Otherwise, the weighted mean difference (WMD) was determined. RESULTS: Overall, the results based on 20 comparative studies showed vitamin D3 to be superior to vitamin D2 in raising total 25(OH)D concentrations, but vitamin D2 and vitamin D3 had a similar positive impact on their corresponding 25(OH)D hydroxylated forms. The WMD in change in total 25(OH)D based on 12 daily dosed vitamin D2-vitamin D3 comparisons, analyzed using liquid chromatography-tandem mass spectrometry, was 10.39 nmol/L (40%) lower for the vitamin D2 group compared with the vitamin D3 group (95% confidence interval: -14.62, -6.16; I2 = 64%; P < 00001). Body mass index (BMI) appeared to be the strongest response modifier, reducing heterogeneity to 0% in both subgroups. The vitamin D2- and vitamin D3-induced change in total 25(OH)D lost significance predominantly in subjects with a BMI >25 kg/m2 (P = 0.99). However, information on BMI was only available in 13/17 daily dosed comparisons. CONCLUSIONS: Vitamin D3 leads to a greater increase of 25(OH)D than vitamin D2, even if limited to daily dose studies, but vitamin D2 and vitamin D3 had similar positive impacts on their corresponding 25(OH)D hydroxylated forms. Next to baseline 25(OH)D concentration, BMI should be considered when comparing the effect of daily vitamin D2 and vitamin D3 supplementation on total 25(OH)D concentration. This study was registered in PROSPERO as CRD42021272674.

Vitamin D deficiency rickets in a toddler.

ABSTRACT: Nutritional rickets is the failure of normal bone formation in children, caused by vitamin D deficiency, low calcium intake, or a combination of both. In the United States, prolonged breastfeeding without vitamin D supplementation is a major risk factor. Increasing awareness of the rationale for and importance of vitamin D supplements for all breastfed infants and children should reduce the incidence of vitamin D deficiency rickets and prevent bone deformity.

How effective is public health policy in Scotland on vitamin D deficiency during pregnancy?

OBJECTIVE: To evaluate the uptake of universal vitamin D supplementation during pregnancy, its effectiveness in preventing vitamin D deficiency and the factors associated with these. DESIGN: The regional public health organisation in Ayrshire, Scotland has a policy of universal provision of vitamin D supplements (10 µg/d) to all pregnant women for the duration of their pregnancy. Pregnant women in this area were recruited at their 12-week antenatal appointment. Blood samples were collected at the 12-week and 34-week appointments. To account for the seasonal variation, women were recruited in two cohorts: summer and winter. Telephone interviews were conducted at 34 weeks to assess the uptake of vitamin D supplements during pregnancy. Other variables were obtained from medical records. SETTING: The study was conducted in the NHS Ayrshire and Arran Health Board in Scotland. PARTICIPANTS: 612 pregnant women (aged 15-44 years) living in Ayrshire (latitude 55°), Scotland. RESULTS: Sixty-six percentage took supplementation as recommended. Consumption of supplementation was significantly associated with a higher median serum 25-hydroxyvitamin D concentrations at 34 weeks. Despite this at 34 weeks, 33 % of the summer cohort had insufficient or deficient vitamin D status, while 15 % of the winter cohort had insufficient or deficient status. In multivariable analysis, only adherence and season were independent predictors of vitamin D status. CONCLUSIONS: While supplementation improved and maintained vitamin D status during pregnancy, it was not adequate to ensure all those insufficient at 12 weeks achieved sufficient status at the end of pregnancy.

The role of vitamin D in the prevention and treatment of SARS-CoV-2 infection: A meta-analysis of randomized controlled trials.

BACKGROUND: Vitamin D (VitD) has been shown to be important for the immune response of the respiratory system, but the preventive and therapeutic effects of vitamin D supplementation on SARS-CoV-2 infection are controversial. This study aimed to determine the role of vitamin D supplementation in the prevention and treatment of SARS-CoV-2 infection through a meta-analysis of randomized controlled trials. METHODS: The databases of PubMed, Cochrane Library, Embase, Web of Science and Google Scholar were searched systematically from inception to April 17,2023 to identify trials involving a randomized comparison of vitamin D supplementation versus non-vitamin D supplementation for SARS-CoV-2 infection prevention or treatment. RESULTS: We retrieved 25 eligible trials, including 8128 participants. Four trials compared the preventive effects of vitamin D supplementation on SARS-CoV-2 infection, and the results (RR 0.31; 95%CI 0.07 to 1.32) were inconclusive. Regarding the treatment of SARS-CoV-2 infection with vitamin D supplementation, it was found that vitamin D supplementation could significantly reduce the rates of ICU admission (RR 0.63; 95%CI 0.44 to 0.89) and mechanical ventilation (RR 0.58; 95%CI 0.39 to 0.84), but had no statistically significant effect on mortality. However, in subgroup analyses based on the patients' specific conditions, vitamin D supplementation significantly reduced the mortality in patients with vitamin D deficiency (RR 0.76; 95%CI 0.58 to 0.98). CONCLUSION: Vitamin D supplementation may have some beneficial impact on the severity of illness caused by SARS-CoV-2, particularly in VitD deficient patients, but further studies are still needed.

Fortification of Staple Foods for Household Use with Vitamin D: An Overview of Systematic Reviews.

Vitamin D deficiency is a global public health concern with significant implications for bone health and chronic disease prevention. Our aim was to summarize the evidence from Cochrane and other systematic reviews evaluating the benefits or harms of vitamin D fortification of staple foods for household use. In April 2023, we systematically searched Ovid MEDLINE, Embase, Epistemonikos and the Cochrane Database of Systematic Reviews for systematic reviews investigating the effects of vitamin D fortification of food in general populations of any age. We used Cochrane methodology and assessed the methodological quality of included studies using AMSTAR (A MeaSurement Tool to Assess Systematic Reviews). We assessed the degree of overlap among reviews. All outcomes included in systematic reviews were assessed. The protocol is registered in PROSPERO (registration number: CRD42023420991). We included 27 systematic reviews out of 5028 records for analysis. Overall, 11 out of 12 systematic reviews calculating pooled estimates reported a significant increase in serum 25(OH)D concentrations. The mean change in serum 25(OH)D concentrations per additional 100 units of vitamin D ranged from 0.7 to 10.8 nmol/L. Fortification of food with vitamin D showed a reduction in the prevalence of vitamin D deficiency based on high-certainty evidence. Parathormone (PTH) levels were described to decrease, bone mineral density to increase, while the effects on other bone turnover markers were inconsistent. Fortification did not significantly impact most anthropometric parameters, but it seemed to positively influence lipid profiles. In summary, fortification of food with vitamin D results in a reduction of vitamin D deficiency and might increase serum 25(OH)D concentrations, to varying extents depending on the fortified vehicle and population characteristics. Additionally, fortification may have a positive impact on bone turnover and lipid metabolism but may only have a limited effect on anthropometric parameters.

Controlling Chronic Diseases and Acute Infections with Vitamin D Sufficiency.

Apart from developmental disabilities, the prevalence of chronic diseases increases with age especially in those with co-morbidities: vitamin D deficiency plays a major role in it. Whether vitamin D deficiency initiates and/or aggravates chronic diseases or vice versa is unclear. It adversely affects all body systems but can be eliminated using proper doses of vitamin D supplementation and/or safe daily sun exposure. Maintaining the population serum 25(OH)D concentration above 40 ng/mL (i.e., sufficiency) ensures a sound immune system, minimizing symptomatic diseases and reducing infections and the prevalence of chronic diseases. This is the most cost-effective way to keep a population healthy and reduce healthcare costs. Vitamin D facilitates physiological functions, overcoming pathologies such as chronic inflammation and oxidative stress and maintaining broader immune functions. These are vital to overcoming chronic diseases and infections. Therefore, in addition to following essential public health and nutritional guidance, maintaining vitamin D sufficiency should be an integral part of better health, preventing acute and chronic diseases and minimize their complications. Those with severe vitamin D deficiency have the highest burdens of co-morbidities and are more vulnerable to developing complications and untimely deaths. Vitamin D adequacy improves innate and adaptive immune systems. It controls excessive inflammation and oxidative stress, generates antimicrobial peptides, and neutralizes antibodies via immune cells. Consequently, vitamin D sufficiency reduces infections and associated complications and deaths. Maintaining vitamin D sufficiency reduces chronic disease burden, illnesses, hospitalizations, and all-cause mortality. Vulnerable communities, such as ethnic minorities living in temperate countries, older people, those with co-morbidities, routine night workers, and institutionalized persons, have the highest prevalence of vitamin D deficiency-they would significantly benefit from vitamin D and targeted micronutrient supplementation. At least now, health departments, authorities, and health insurance companies should start assessing, prioritizing, and encouraging this economical, non-prescription, safe micronutrient to prevent and treat acute and chronic diseases. This approach will significantly reduce morbidity, mortality, and healthcare costs and ensure healthy aging.

Randomised controlled trial of perinatal vitamin D supplementation to prevent early-onset acute respiratory infections among Australian First Nations children: the 'D-Kids' study protocol.

INTRODUCTION: Globally, acute respiratory infections (ARIs) are a leading cause of childhood morbidity and mortality. While ARI-related mortality is low in Australia, First Nations infants are hospitalised with ARIs up to nine times more often than their non-First Nations counterparts. The gap is widest in the Northern Territory (NT) where rates of both acute and chronic respiratory infection are among the highest reported in the world. Vitamin D deficiency is common among NT First Nations neonates and associated with an increased risk of ARI hospitalisation. We hypothesise that perinatal vitamin D supplementation will reduce the risk of ARI in the first year of life. METHODS AND ANALYSIS: 'D-Kids' is a parallel (1:1), double-blind (allocation concealed), randomised placebo-controlled trial conducted among NT First Nations mother-infant pairs. Pregnant women and their babies (n=314) receive either vitamin D or placebo. Women receive 14 000 IU/week or placebo from 28 to 34 weeks gestation until birth and babies receive 4200 IU/week or placebo from birth until age 4 months. The primary outcome is the incidence of ARI episodes receiving medical attention in the first year of life. Secondary outcomes include circulating vitamin D level and nasal pathogen prevalence. Tertiary outcomes include infant immune cell phenotypes and challenge responses. Blood, nasal swabs, breast milk and saliva are collected longitudinally across four study visits: enrolment, birth, infant age 4 and 12 months. The sample size provides 90% power to detect a 27.5% relative reduction in new ARI episodes between groups. ETHICS AND DISSEMINATION: This trial is approved by the NT Human Research Ethics Committee (2018-3160). Study outcomes will be disseminated to participant families, communities, local policy-makers, the broader research and clinical community via written and oral reports, education workshops, peer-reviewed journals, national and international conferences. TRIAL REGISTRATION NUMBER: ACTRN12618001174279.