Skin Color Is Relevant to Vitamin D Synthesis

Libon, Florence; Cavalier, Étienne; Nikkels, Arjen F.

doi:10.1159/000354750

Cited by 110 publications

(84 citation statements)

References 21 publications

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“…In contrast, the concentration was <15 ng/mL in only 10-40% of the CKD patients in previous studies (9,(23)(24)(25)(26). One possible reason for this difference could be racial differences among the patient groups, since the main source of vitamin D is synthesis from the skin by sunlight, which differs among the races (2,27,28). Another reason could be the study period; the patients were enrolled in the winter season when 25(OH)D levels are usually lower due to shorter periods of sunlight (20,29).…”

Section: Discussionmentioning

confidence: 88%

The Prevalence of 25-hydroxyvitamin D Deficiency in Japanese Patients with Diabetic Nephropathy

et al. 2016

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Objective The purpose of this study was to measure serum 25-hydroxyvitamin D [25(OH)D] levels in Japanese patients with diabetic nephropathy and determine the relationship between 25(OH)D concentrations and various factors. Methods The study subjects included 442 patients with type 2 diabetes. Their serum levels of creatinine, HbA1c, intact-parathyroid hormone, urinary albumin, 25(OH)D, and 1,25-dihydroxyvitamin D [1,25(OH)2D] were measured and their estimated glomerular filtration rate (eGFR) was determined. The patients were divided into four groups based on the risk for progression to chronic kidney disease (CKD): low, moderate, high, very high, based on their eGFR and their level of albuminuria. Results The median 25(OH)D level was 14.6 ng/mL; 11% of the patients had 25(OH)D deficiency (<10 ng/ mL), and 2% of patients had active vitamin D deficiency, as defined by a 1,25(OH)2D level of <22 pg/mL. The serum 25(OH)D level was correlated with the serum 1,25(OH)2D level in patients with a very high risk for CKD, but not in those with a moderate or high risk for CKD. Conclusion Although the vitamin D levels of the Japanese patients with diabetic nephropathy and CKD were low, the prevalence of vitamin D deficiency, as defined by the 1,25(OH)2D level, was low. Albuminuria, younger age, and female gender were associated with a low 25(OH)D level. The serum level of 25(OH)D should be monitored to assess the vitamin D status of patients with nephropathy and CKD.

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Section: Discussionmentioning

confidence: 88%

The Prevalence of 25-hydroxyvitamin D Deficiency in Japanese Patients with Diabetic Nephropathy

et al. 2016

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“…This finding may appear counterintuitive; however, detailed experimental studies of the relation between pigmentation and the response of 25(OH)D to UV radiation also found little correlation (30). Other observational epidemiologic studies showed no association between pigmentation and 25(OH)D concentrations (31), a negative correlation (32,33), and even a positive effect of skin pigmentation on serum concentratons of 25(OH)D (34). Further large studies will be required to answer this question.…”

Section: Discussionmentioning

confidence: 98%

25-Hydroxyvitamin D in African-origin populations at varying latitudes challenges the construct of a physiologic norm , ,

Durazo‐Arvizu

Camacho

Bovet

et al. 2014

The American Journal of Clinical Nutrition

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Background: The vitamin D-endocrine system is thought to play a role in physiologic processes that range from mineral metabolism to immune function. Serum 25-hydroxyvitamin D [25(OH)D] is the accepted biomarker for vitamin D status. Skin color is a key determinant of circulating 25(OH)D concentrations, and genes responsible for melanin content have been shown to be under strong evolutionary selection in populations living in temperate zones. Little is known about the effect of latitude on mean concentrations of 25(OH)D in dark-skinned populations. Objective: The objective was to describe the distribution of 25(OH)D and its subcomponents in 5 population samples of African origin from the United States, Jamaica, Ghana, South Africa, and the Seychelles. Design: Participants were drawn from the Modeling of the Epidemiologic Transition Study, a cross-sectional observational study in 2500 adults, ages 25-45 y, enrolled between January 2010 and December 2011. Five hundred participants, w50% of whom were female, were enrolled in each of 5 study sites: Chicago, IL (latitude: 418N); Kingston, Jamaica (178N); Kumasi, Ghana (68N); Victoria, Seychelles (48S); and Cape Town, South Africa (348S). All participants had an ancestry primarily of African origin; participants from the Seychelles trace their history to East Africa. Results: A negative correlation between 25(OH)D and distance from the equator was observed across population samples. The frequency distribution of 25(OH)D in Ghana was almost perfectly normal (Gaussian), with progressively lower means and increasing skewness observed at higher latitudes. Conclusions: It is widely assumed that lighter skin color in populations outside the tropics resulted from positive selection, driven in part by the relation between sun exposure, skin melanin content, and 25(OH)D production. Our findings show that robust compensatory mechanisms exist that create tolerance for wide variation in circulating concentrations of 25(OH)D across populations, suggesting a more complex evolutionary relation between skin color and the vitamin D pathway. This trial was registered at clinicaltrials.gov as NCT02111902.

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“…One such factor is the amount of ultraviolet B rays emitted and absorbed, which are influenced by latitude and skin pigmentation, respectively [23]. In a study by Libon et al [24], serum vitamin D concentrations were evaluated in patients with light and dark skin pigmentation. Despite controlling for sun exposure, those with light skin pigmentation exhibited higher serum vitamin D concentrations compared to those with darker skin pigmentation.…”

Section: Metabolic and Physiological Aspects Of Vitamin Dmentioning

confidence: 99%

Role of vitamin D in insulin resistance in obese individuals

Santos

Lima

Braz

et al. 2017

Nutrire

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Background: Vitamin D is a fat-soluble compound responsible for promoting intestinal absorption of calcium, and this, in turn, acts as a signal transmitter or activator as protein in secretory processes and release of hormones. Vitamin D receptors are distributed in various tissues of the body and involved in biochemical reactions in the pathogenesis of several diseases, such as obesity. Objective: The aim of this article is to provide updated information on the role of vitamin D in insulin resistance in obese individuals. Methods: It was conducted a search of articles published in PubMED, SciELO, and LILACS database, without limit for the year of publication, using the keywords "vitamin D", "insulin resistance", and "obesity". Results: Excess adipose tissue seems to impair insulin signaling by inhibiting the phosphorylation of its receptor, resulting in insulin resistance. Studies have evidenced role of vitamin D in mechanisms involved in the pathogenesis of insulin resistance in obesity by acting in improving glycemic control both by increasing hepatic and peripheral glucose uptake and by promoting the secretion of this hormone. Conclusions: Vitamin D exerts a protective effect in the treatment and prevention of insulin resistance in patients with obesity and protects the body against oxidative stress and chronic inflammation, contributing to glycemic control. Unfortunately, current data related to the effects of vitamin D supplementation on insulin resistance are still inconclusive.

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Skin Color Is Relevant to Vitamin D Synthesis

Cited by 110 publications

References 21 publications

The Prevalence of 25-hydroxyvitamin D Deficiency in Japanese Patients with Diabetic Nephropathy

The Prevalence of 25-hydroxyvitamin D Deficiency in Japanese Patients with Diabetic Nephropathy

25-Hydroxyvitamin D in African-origin populations at varying latitudes challenges the construct of a physiologic norm , ,

Role of vitamin D in insulin resistance in obese individuals

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