Study Design for Vitamin D Randomized Clinical Trials

Abstract The COVID-19 pandemic presents challenges to the conduct of randomized clinical trials of lifestyle interventions. World-Wide FINGERS international network convened a forum for researchers to discuss statistical design and analysis issues they faced during the pandemic. We report experiences of three trials that, at various stages of conduct, altered designs and analysis plans to navigate these issues. We provide recommendations for future trials to consider as they develop and launch behavioral intervention trials. The pandemic led researchers to change recruitment plans, interrupt timelines for assessments and intervention delivery, and move to remote intervention and assessments protocols. The necessity of these changes add emphasis to the importance, in study design and analysis, of intention to treat approaches, flexibility, within site stratification, interim power projections, and sensitivity analyses. Robust approaches to study design and analysis are critical to negotiate issues related to the intervention.

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Vitamin D, respiratory infections, and chronic disease: Review of meta‐analyses and randomized clinical trials

Journal of Internal Medicine ◽

10.1111/joim.13399 ◽

2021 ◽

Author(s):

Davaasambuu Ganmaa ◽

Davaasambuu Enkhmaa ◽

Erdenebileg Nasantogtoh ◽

Surenmaa Sukhbaatar ◽

Khash‐Erdene Tumur‐Ochir ◽

...

Keyword(s):

Vitamin D ◽

Clinical Trials ◽

Chronic Disease ◽

Randomized Clinical Trials ◽

Respiratory Infections ◽

Meta Analyses

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Vitamin D Food Fortification and Nutritional Status in Children: A Systematic Review of Randomized Controlled Trials

Nutrients ◽

10.3390/nu11112766 ◽

2019 ◽

Vol 11 (11) ◽

pp. 2766 ◽

Cited By ~ 2

Author(s):

Paula Nascimento Brandão-Lima ◽

Beatriz da Cruz Santos ◽

Concepción Maria Aguilera ◽

Analícia Rocha Santos Freire ◽

Paulo Ricardo Saquete Martins-Filho ◽

...

Keyword(s):

Systematic Review ◽

Vitamin D ◽

Clinical Trials ◽

Nutritional Status ◽

Systematic Reviews ◽

Randomized Clinical Trials ◽

Hypovitaminosis D ◽

Food Fortification ◽

Fortified Foods ◽

Eligibility Criteria

Children are in the risk group for developing hypovitaminosis D. Several strategies are used to reduce this risk. Among these, fortification of foods with vitamin D (25(OH)D) has contributed to the achievement of nutritional needs. This systematic review aims to discuss food fortification as a strategy for maintenance or recovery of nutritional status related to vitamin D in children. The work was developed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and registered in the International prospective register of systematic reviews (PROSPERO) database (CRD42018052974). Randomized clinical trials with children up to 11 years old, who were offered vitamin D-fortified foods, and who presented 25(OH)D concentrations were used as eligibility criteria. After the selection stages, five studies were included, totaling 792 children of both sexes and aged between two and 11 years. Interventions offered 300–880 IU of vitamin D per day, for a period of 1.6–9 months, using fortified dairy products. In four of the five studies, there was an increase in the serum concentrations of 25(OH)D with the consumption of these foods; additionally, most children reached or maintained sufficiency status. Moreover, the consumption of vitamin D-fortified foods proved to be safe, with no concentrations of 25(OH)D > 250 nmol/L. Based on the above, the fortification of foods with vitamin D can help maintain or recover the nutritional status of this vitamin in children aged 2–11 years. However, it is necessary to perform additional randomized clinical trials in order to establish optimal doses of fortification, according to the peculiarities of each region.

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