Effect of solar ultraviolet radiation exposure on serum 25(OH)D concentration: a pilot randomised controlled trial

Infections and Autoimmunity-The Immune System and Vitamin D: A Systematic Review

Both 25-autoimmunity and(25(OH)D: calcifediol) and its active form, 1,25-dihydroxyvitamin D (1,25(OH)2D: calcitriol), play critical roles in protecting humans from invasive pathogens, reducing risks of autoimmunity, and maintaining health. Conversely, low 25(OH)D status increases susceptibility to infections and developing autoimmunity. This systematic review examines vitamin D's mechanisms and effects on enhancing innate and acquired immunity against microbes and preventing autoimmunity. The study evaluated the quality of evidence regarding biology, physiology, and aspects of human health on vitamin D related to infections and autoimmunity in peer-reviewed journal articles published in English. The search and analyses followed PRISMA guidelines. Data strongly suggested that maintaining serum 25(OH)D concentrations of more than 50 ng/mL is associated with significant risk reduction from viral and bacterial infections, sepsis, and autoimmunity. Most adequately powered, well-designed, randomized controlled trials with sufficient duration supported substantial benefits of vitamin D. Virtually all studies that failed to conclude benefits or were ambiguous had major study design errors. Treatment of vitamin D deficiency costs less than 0.01% of the cost of investigation of worsening comorbidities associated with hypovitaminosis D. Despite cost-benefits, the prevalence of vitamin D deficiency remains high worldwide. This was clear among those who died from COVID-19 in 2020/21-most had severe vitamin D deficiency. Yet, the lack of direction from health agencies and insurance companies on using vitamin D as an adjunct therapy is astonishing. Data confirmed that keeping an individual's serum 25(OH)D concentrations above 50 ng/mL (125 nmol/L) (and above 40 ng/mL in the population) reduces risks from community outbreaks, sepsis, and autoimmune disorders. Maintaining such concentrations in 97.5% of people is achievable through daily safe sun exposure (except in countries far from the equator during winter) or taking between 5000 and 8000 IU vitamin D supplements daily (average dose, for non-obese adults, ~70 to 90 IU/kg body weight). Those with gastrointestinal malabsorption, obesity, or on medications that increase the catabolism of vitamin D and a few other specific disorders require much higher intake. This systematic review evaluates non-classical actions of vitamin D, with particular emphasis on infection and autoimmunity related to the immune system.

Estimation of the vitamin D (VD) status of pregnant Japanese women based on food intake and VD synthesis by solar UV-B radiation using a questionnaire and UV-B observations

Although vitamin D (VD; serum 25 hydroxyvitamin D) deficiency (< 20 ng/mL) is widespread among Japanese women, the VD status among pregnant women is unknown. This study aimed to determine the VD status of pregnant Japanese women during different meteorological seasons and to determine the factors controlling VD status. A total of 309 pregnant Japanese women were recruited at 28 weeks of gestation at the gynecology department of a university hospital in Tokyo between August 2018 and October 2019. Blood samples were collected to measure serum 25(OH)D levels. Two questionnaires were completed: a brief self-administered dietary history questionnaire (BDHQ) and an outdoor exposure history questionnaire to determine skin sunlight exposure and the use of sunscreen. Among the recruited subjects, 268 were included in the statistical analysis. The average VD intake from food was 9.0 μg/day, the average VD synthesis from UV-B was 15.2 μg/day, and the average sum of VD intake and nominal VD synthesis was 24.1 μg/day; this exceeded the recommended 2011 Dietary Reference Intake for the USA and Canada (15.0 μg/day). However, the average serum 25(OH)D level (11.4 ng/mL) was very low, indicating widespread VD deficiency. Serum 25(OH)D and VD synthesis by solar UV-B were significantly correlated only during the high UV-B season. The 25(OH)D level was weakly correlated with the VD intake from food in all seasons. We obtained a statistically significant correlation between serum 25(OH)D level and VD intake from food using the BDHQ. We also obtained a statistically significant correlation between the serum 25(OH)D level and VD synthesis from solar UV-B exposure, especially during the high UV-B season. Our logistic regression analysis model predicted VD deficiency in 88.0% of subjects. Our method might be possible to be used to predict the VD status of pregnant Japanese women, although another validation cohort is needed to verify the ability of the estimation equation.

Concerns about vitamin D and sun exposure behaviour among Australians

ISSUES ADDRESSED

Australians' concerns about vitamin D and influence on sun protection were last quantified a decade ago in Queensland amidst media attention on emerging evidence of non-skeletal benefits of vitamin D. Meanwhile these circumstances persist and impact is worth assessing.

METHODS

Measures of concern about vitamin D were included in three recent population-based cross-sectional surveys of Australians' sun-related behaviours during summer months (2010-2011, 2013-2014 and 2016-2017). We analysed characteristics, beliefs and behaviours associated with vitamin D concerns regarding regular sunscreen use among adults in 2016-2017 (N = 3614).

RESULTS

Concerns about vitamin D continued to persist among adults surveyed between 2010-2011 and 2016-2017. Vitamin D concerns regarding the sunscreen use were more common among women, older respondents and adults with skin that tans or is not susceptible to sunburn. Respondents concerned about vitamin D were more likely to exhibit pro-tanning beliefs, scepticism about sunscreen safety and have attempted a suntan. They were also less likely to use sun protection in everyday activities outdoors and less likely to use sunscreen on summer weekends.

CONCLUSIONS

Vitamin D concerns related to sunscreen use remained common among Australian adults. Skin cancer control advocates may be reassured that those with the greatest skin cancer risk (burn only) were less likely to hold these concerns, while the related infrequent sun protection and tanning among concerned adults are problematic. SO WHAT?: Continued education and research is needed to ensure that the general public understand the risks and benefits of sun exposure in Australia.

Can Current Recommendations on Sun Exposure Sufficiently Increase Serum Vitamin D Level?: One-Month Randomized Clinical Trial

BACKGROUND

Lack of sunlight exposure is the primary reason for the worldwide epidemic of vitamin D deficiency. Although recommended sunlight exposure guidelines exist, there is no evidence regarding whether current guidelines are optimal for increasing vitamin D levels among individuals with vitamin D deficiency.

METHODS

Sixty Korean adults aged 20-49 years with serum 25-hydroxyvitamin D (25[OH]D) levels of < 20 ng/mL were randomly assigned to three groups: sunlight exposure (n = 20), vitamin D supplementation groups (n = 20), and daily living (n = 20) for 1 month. The sunlight exposure group had sunlight exposure on 20% to 30% of their body surface areas for 30-60 minutes per day, 3 times a week during the summer season. Vitamin D supplementation was prescribed with 800 IU/day of vitamin D. The serum levels of 25(OH)D were measured at baseline and at 1-month follow-up examinations.

RESULTS

The largest change in serum 25(OH)D was observed among the vitamin D supplementation group (+3.5 ng/mL, P < 0.001). The sunlight exposure group showed a slight increase in serum 25(OH)D level, but the absolute increase was less than one-third that of the vitamin D supplementation group (+0.9 ng/mL, P = 0.043). Only two participants in the sunlight exposure reached serum concentrations of 25(OH)D ≥ 20 ng/mL at follow-up. The daily living group showed no difference in vitamin D levels (-0.7 ng/mL, P = 0.516).

CONCLUSION

Sunlight exposure was not sufficient to overcome vitamin D insufficiency or deficiency in the current study subjects. Effectiveness of current sunlight exposure guidelines among various populations should be reassessed in larger clinical studies.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0002671.

From Samples to Insights into Metabolism: Uncovering Biologically Relevant Information in LC-HRMS Metabolomics Data

Untargeted metabolomics (including lipidomics) is a holistic approach to biomarker discovery and mechanistic insights into disease onset and progression, and response to intervention. Each step of the analytical and statistical pipeline is crucial for the generation of high-quality, robust data. Metabolite identification remains the bottleneck in these studies; therefore, confidence in the data produced is paramount in order to maximize the biological output. Here, we outline the key steps of the metabolomics workflow and provide details on important parameters and considerations. Studies should be designed carefully to ensure appropriate statistical power and adequate controls. Subsequent sample handling and preparation should avoid the introduction of bias, which can significantly affect downstream data interpretation. It is not possible to cover the entire metabolome with a single platform; therefore, the analytical platform should reflect the biological sample under investigation and the question(s) under consideration. The large, complex datasets produced need to be pre-processed in order to extract meaningful information. Finally, the most time-consuming steps are metabolite identification, as well as metabolic pathway and network analysis. Here we discuss some widely used tools and the pitfalls of each step of the workflow, with the ultimate aim of guiding the reader towards the most efficient pipeline for their metabolomics studies.