Statistical power in vitamin D randomized control trials investigating biomarkers as continuous outcomes

Zgaga, Lina; Shraim, Rasha; Bolger, Elizabeth; Wyse, Jason

doi:10.1016/j.jsbmb.2022.106148

Cited by 9 publications

(6 citation statements)

References 26 publications

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“…On a separate but very important note, understanding seasonal changes in UVB and vitamin D is also important for interpreting findings from vitamin D randomized controlled trials [ 45 ], because seasonal fluctuation can undermine the trial power and drive null-findings [ 46 , 47 ].…”

Section: Discussionmentioning

confidence: 99%

Comprehensive Analysis of Seasonal and Geographical Variation in UVB Radiation Relevant for Vitamin D Production in Europe

et al. 2022

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Dermal synthesis, following sun exposure, is the main source of vitamin D. This study characterizes ambient UVB radiation relevant for vitamin D production in Europe. A biological weighing function was applied to data from the Tropospheric Emissions Monitoring Internet Service (TEMIS) for 46 capital cities over an 18-year period (2004–2021) to isolate wavelengths relevant for vitamin D production (D-UVB). Cumulative and weighted D-UVB (CW-D-UVB) were calculated to approximate seasonal vitamin D accumulation and diminution. Monthly 25(OH)D concentration measurements were extracted from published reports. All data were analyzed by location and time. Despite a moderate latitudinal range (35–64° N), we observed large—up to five-fold—regional differences: the highest mean diurnal D-UVB dose of 5.57 kJ/m2 (SD = 3.55 kJ/m2) was observed in Nicosia (Cyprus) and the lowest in Reykjavik (Iceland, 1.16 ± 1.29 kJ/m2). Seasonal differences in diurnal D-UVB dose were even more pronounced, with a median 36-fold difference between annual peak and trough depending on a location (range: 10- to 525-fold). The mean duration of “vitamin D winter” was 126 days but varied widely (4 to 215 days). Monthly CW-D-UVB and 25(OH)D changes were very strongly correlated: the changes in 25(OH)D concentration increased by 12.6 nmol/L for every 100 kJ/m2 increment of CW-D-UVB in population-based studies (r2 = 0.79, p-value = 1.16 × 10−37). Understanding the differences in D-UVB radiation can help understand determinants of vitamin D status and guide region- and season-specific safe and effective sunlight exposure recommendations and vitamin D supplementation guidelines.

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Section: Discussionmentioning

confidence: 99%

Comprehensive Analysis of Seasonal and Geographical Variation in UVB Radiation Relevant for Vitamin D Production in Europe

et al. 2022

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“…Confusion concerning the value of a vitD supplementation has existed for decades due to the claim that only RCTs can be used as a benchmark for assessment, especially since there are considerable discussions concerning the evaluation of such studies [235][236][237]. However, there are potential limitations so that RCTs alone are not able to provide a definitive answer [238][239][240][241]. There is a demand for the improvement of statistical significance in randomized VitD control studies using Tregs as a benchmark [242].…”

Section: Criticism Of Rcts-an Unsolved Problemmentioning

confidence: 99%

Multiple sclerosis with comorbidity depression and its association with vitamin D deficiency in a narrative review of the current literature

Goischke

2023

Explor Neurosci

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Over the past decade, knowledge of the pathophysiology and immunology of multiple sclerosis (MS) and depression, and the complex links to vitamin D (VitD) balance, has increased rapidly. Both diseases are characterized by an imbalance of proinflammatory and antiinflammatory cytokines, increased serum neurofilament light chains (sNfLs), disruption of the blood-brain barrier (BBB), abolition of the physiological function of the various types of microglia (MG), decreased calcidiol-serum levels, and disorders of the gut microbiome in combination with hyperactivity of the hypothalamic-pituitary-adrenal (HPA)-axis/microbiome-gut-brain-axis characterized. In depression, stress initiates cellular and molecular changes in the brain via increased cortisol release in the HPA-axis. Microglial activation and neuronal damage as well as dysregulation of neuroplastic and neurotrophic factors complete the spectrum of pathological damage. It is shown that gut dysbiosis leads to increased gut permeability, which favors endotoxemia and ultimately paves the way to systemic inflammation. A VitD supplementation could restore the balance of microorganisms in the intestine and reduce the inflammatory processes at various levels. VitD promotes regulatory T cell (Treg) proliferation, inhibits the expression of T helper 1 (Th1) cells and Th17 immune cells, and inhibits proinflammatory interleukin-17 (IL-17). 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] reduces also the secretion of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). Increased calcitriol levels lead to a reduction in MG activation, oxidative stress, and lower BBB permeability. An early, permanent, daily sufficient VitD supplementation as an add-on therapy under control of the serum 25-hydroxyvitamin D [s25(OH)D] levels is an essential therapeutic tool to slow down the disability caused by MS and thereby primarily prevent or reduce the stress and subsequently the manifestation of depression. Through the future continuous measurement of the biomarkers serum neurofilament ligth chains and glial fibrillary acidic proteins as well as the s25(OH)D level in MS and comorbidity depression, future therapy successes or failures can be avoided.

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“…Degerud et al (2016) investigated the seasonal 25-hydroxyvitamin D (25(OH)D) levels in cardiovascular diseases [28]. In another study conducted by Zgaga et al (2022), statistical power was evaluated in randomized controlled trials investigating 25(OH)D [29]. Additionally, a 2015 Irish study evaluated at the trend of 25(OH)D over 20 years from 1993 to 2013 [30].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of 25-hydroxyvitamin D (25(OH)D) levels before and during the COVID-19 pandemic: A cross-sectional study and trend analysis involving 86,772 samples

et al. 2023

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Background The aim of this paper was to evaluate the change in 25-hidroxyvitamin D (25(OH)D) levels before and during the COVID-19 pandemic. Methods In this retrospective, cross-sectional and methodological study included 86,772 patients (18–75 years) samples who were admitted to the Izmir Dokuz Eylul University Hospital (latitude and longitude (Turkey): 27 E 09; 38 N 25, respectively) for various reasons and whose 25(OH)D levels were measured in the biochemistry unit between 2019–2020 and 2020–2021 (before and during the COVID-19 outbreak). A time series analysis of monthly averages for 25(OH)D was performed. For the purpose of seasonal study, the mean levels of 25(OH)D are grouped by years. Data were modeled in terms of 25(OH)D levels using the MATLAB Curve Fitting Toolbox. Results There was no significant difference between the sexes according to 25(OH)D levels (p>0.05). 25(OH)D levels were significantly higher in the summer months and lower in the winter months (p<0.001). When comparing the spring months, 25(OH)D levels in 2020 (18 ± 10) were found to be significantly lower than in 2019 (22 ± 12) (p<0.001); on the contrary, when examined based on the summer, autumn, and winter months, it was determined that 25(OH)D levels increased in 2020 (summer: 25 ± 13, autumn: 25 ± 14, and winter: 19 ± 10) compared to 2019 (summer: 23 ± 11, autumn: 22 ± 10, and winter: 19 ± 11) (p<0.001). In the estimates curve obtained with an error margin of 11% in the time series analysis, it was estimated that the 25(OH)D averages after the pandemic would be similar to those before the pandemic. Conclusions Restrictions, partial or complete closures, and curfews can significantly affect individuals’ 25(OH)D levels during the COVID-19 outbreak. There is a need for multicenter studies with larger populations covering different regions to strengthen and support our results.

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Statistical power in vitamin D randomized control trials investigating biomarkers as continuous outcomes

Cited by 9 publications

References 26 publications

Comprehensive Analysis of Seasonal and Geographical Variation in UVB Radiation Relevant for Vitamin D Production in Europe

Comprehensive Analysis of Seasonal and Geographical Variation in UVB Radiation Relevant for Vitamin D Production in Europe

Multiple sclerosis with comorbidity depression and its association with vitamin D deficiency in a narrative review of the current literature

Evaluation of 25-hydroxyvitamin D (25(OH)D) levels before and during the COVID-19 pandemic: A cross-sectional study and trend analysis involving 86,772 samples

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