1
|
Singh Ospina N, Diaz-Thomas A, McDonnell ME, Demay MB, Pittas AG, York E, Corrigan MD, Lash RW, Brito JP, Murad MH, McCartney CR. Navigating Complexities: Vitamin D, Skin Pigmentation, and Race. J Clin Endocrinol Metab 2024:dgae314. [PMID: 38828960 DOI: 10.1210/clinem/dgae314] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Indexed: 06/05/2024]
Abstract
Vitamin D plays a critical role in many physiological functions, including calcium metabolism and musculoskeletal health. This commentary aims to explore the intricate relationships among skin complexion, race, and 25-hydroxyvitamin D (25[OH]D) levels, focusing on challenges the Endocrine Society encountered during clinical practice guideline development. Given that increased melanin content reduces 25(OH)D production in the skin in response to UV light, the guideline development panel addressed the potential role for 25(OH)D screening in individuals with dark skin complexion. The panel discovered that no randomized clinical trials have directly assessed vitamin D related patient-important outcomes based on participants' skin pigmentation, although race and ethnicity often served as presumed proxies for skin pigmentation in the literature. In their deliberations, guideline panel members and selected Endocrine Society leaders underscored the critical need to distinguish between skin pigmentation as a biological variable and race and ethnicity as socially determined constructs. This differentiation is vital to maximize scientific rigor and, thus, the validity of resulting recommendations. Lessons learned from the guideline development process emphasize the necessity of clarity when incorporating race and ethnicity into clinical guidelines. Such clarity is an essential step toward improving health outcomes and ensuring equitable healthcare practices.
Collapse
Affiliation(s)
- Naykky Singh Ospina
- Division of Endocrinology, University of Florida, Gainesville, FL 32610, USA
| | - Alicia Diaz-Thomas
- Division of Pediatric Endocrinology, Department of Pediatrics, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Marie E McDonnell
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Marie B Demay
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Anastassios G Pittas
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Tufts Medical Center, Boston, MA 02111, USA
| | | | | | | | - Juan P Brito
- Division of Diabetes, Endocrinology, Metabolism, and Nutrition, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - M Hassan Murad
- Mayo Clinic, Evidence-Based Practice Center, Rochester, MN 55905, USA
| | - Christopher R McCartney
- Division of Endocrinology and Metabolism, Department of Medicine, West Virginia University, Morgantown, WV 26506, USA
| |
Collapse
|
2
|
Hendi NN, Chakhtoura M, Al-Sarraj Y, Basha DS, Albagha O, Fuleihan GEH, Nemer G. The Genetic Architecture of Vitamin D Deficiency among an Elderly Lebanese Middle Eastern Population: An Exome-Wide Association Study. Nutrients 2023; 15:3216. [PMID: 37513634 PMCID: PMC10384558 DOI: 10.3390/nu15143216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/28/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
The Middle East region experiences a high prevalence of vitamin D deficiency, yet most genetic studies on vitamin D have focused on European populations. Furthermore, there is a lack of research on the genomic risk factors affecting elderly people, who are more susceptible to health burdens. We investigated the genetic determinants of 25-hydroxyvitamin D concentrations in elderly Lebanese individuals (n = 199) through a whole-exome-based genome-wide association study. Novel genomic loci displaying suggestive evidence of association with 25-hydroxyvitamin D levels were identified in our study, including rs141064014 in the MGAM (p-value of 4.40 × 10-6) and rs7036592 in PHF2 (p-value of 8.43 × 10-6). A meta-analysis of the Lebanese data and the largest European genome-wide association study confirmed consistency replication of numerous variants, including rs2725405 in SLC38A10 (p-value of 3.73 × 10-8). Although the polygenic risk score model derived from European populations exhibited lower performance than European estimations, it still effectively predicted vitamin D deficiency among our cohort. Our discoveries offer novel perspectives on the genetic mechanisms underlying vitamin D deficiency among elderly Middle Eastern populations, facilitating the development of personalized approaches for more effective management of vitamin D deficiency. Additionally, we demonstrated that whole-exome-based genome-wide association study is an effective method for identifying genetic components associated with phenotypes.
Collapse
Affiliation(s)
- Nagham Nafiz Hendi
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha P.O. Box 34110, Qatar
| | - Marlene Chakhtoura
- Calcium Metabolism & Osteoporosis Program, American University of Beirut Medical Center, Beirut P.O. Box 11-0236, Lebanon
| | - Yasser Al-Sarraj
- Qatar Genome Program (QGP), Qatar Foundation Research, Development and Innovation, Qatar Foundation (QF), Doha P.O. Box 5825, Qatar
| | - Dania Saleh Basha
- Calcium Metabolism & Osteoporosis Program, American University of Beirut Medical Center, Beirut P.O. Box 11-0236, Lebanon
| | - Omar Albagha
- Division of Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha P.O. Box 34110, Qatar
| | - Ghada El-Hajj Fuleihan
- Calcium Metabolism & Osteoporosis Program, American University of Beirut Medical Center, Beirut P.O. Box 11-0236, Lebanon
| | - Georges Nemer
- Division of Genomics and Translational Biomedicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha P.O. Box 34110, Qatar
- Department of Biochemistry and Molecular Genetics, American University of Beirut, Beirut P.O. Box 11-0236, Lebanon
| |
Collapse
|
3
|
Bonilla C, Herrera G, Sans M. What can Mendelian randomization contribute to biological anthropology? AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023. [PMID: 37114747 DOI: 10.1002/ajpa.24750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/27/2023] [Accepted: 04/09/2023] [Indexed: 04/29/2023]
Abstract
Uncovering causal relationships between exposures and outcomes can be difficult in observational studies because of the potential for confounding and reverse causation to produce biased estimates. Conversely, randomized controlled trials (RCTs) provide the strongest evidence for causality but they are not always feasible. Mendelian randomization (MR) is a method that aims to strengthen causal inference using genetic variants as proxies or instrumental variables (IVs) for exposures, to overcome the above-mentioned biases. Since allele segregation occurs at random from parents to offspring, and alleles for a trait assort independently from those for other traits, MR studies have frequently been compared to "natural" RCTs. In biological anthropology (BA) relationships between variables of interest are usually evaluated using observational data, often remaining descriptive, and other approaches to causal inference have seldom been implemented. Here, we propose the use of MR to investigate cause and effect relationships in BA studies and provide examples to show how that can be done across areas of BA relevance, such as adaptation to the environment, nutrition and life history theory. While we consider MR a useful addition to the biological anthropologist's toolbox, we advocate the adoption of a wide range of methods, affected by different types of biases, in order to better answer the important causal questions for the discipline.
Collapse
Affiliation(s)
- Carolina Bonilla
- Departamento de Medicina Preventiva, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Guadalupe Herrera
- Departamento de Antropología Biológica, Facultad de Humanidades y Ciencias de la Educación, Universidad de la República, Montevideo, Uruguay
- Departamento de Métodos Cuantitativos, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- Departamento de Medicina Preventiva y Social, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Mónica Sans
- Departamento de Antropología Biológica, Facultad de Humanidades y Ciencias de la Educación, Universidad de la República, Montevideo, Uruguay
| |
Collapse
|
4
|
Okunola AO, Baatjes KJ, Zemlin AE, Torrorey-Sawe R, Conradie M, Kidd M, Erasmus RT, van der Merwe NC, Kotze MJ. Pathology-supported genetic testing for the application of breast cancer pharmacodiagnostics: family counselling, lifestyle adjustments and change of medication. Expert Rev Mol Diagn 2023; 23:431-443. [PMID: 37060281 DOI: 10.1080/14737159.2023.2203815] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
BACKGROUND Pathology-supported genetic testing (PSGT) enables transitioning of risk stratification from the study population to the individual. RESEARCH DESIGN AND METHODS We provide an overview of the translational research performed in postmenopausal breast cancer patients at increased risk of osteoporosis due to aromatase inhibitor therapy, as the indication for referral. Both tumour histopathology and blood biochemistry levels were assessed to identify actionable disease pathways using whole exome sequencing (WES). RESULTS The causes and consequences of inadequate vitamin D levels as a modifiable risk factor for bone loss were highlighted in 116 patients with hormone receptor-positive breast cancer. Comparison of lifestyle factors and WES data between cases with vitamin D levels at extreme upper and lower ranges identified obesity as a major discriminating factor, with the lowest levels recorded during winter. Functional polymorphisms in the vitamin D receptor gene contributed independently to therapy-related osteoporosis risk. In a patient with invasive lobular carcinoma, genetic counselling facilitated investigation of the potential modifying effect of a rare CDH1 variant co-occurring withBRCA1 c.66dup (p.Glu23ArgfsTer18). CONCLUSION Validation of PSGT as a three-pronged pharmacodiagnostics tool for generation of adaptive reports and data reinterpretation during follow-up represents a new paradigm in personalised medicine, exposing significant limitations to overcome.
Collapse
Affiliation(s)
- Abisola O Okunola
- Division of Chemical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Karin J Baatjes
- Department of Surgical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Annalise E Zemlin
- Division of Chemical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
- Division of Chemical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University and the National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa
| | - Rispah Torrorey-Sawe
- Division of Chemical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
- Department of Immunology, School of Medicine, College of Health Sciences, Moi University, Eldoret, Kenya
| | - Magda Conradie
- Division of Endocrinology, Department of Medicine, Faculty of Medicine and Health Sciences Stellenbosch University, Cape Town, South Africa
| | - Martin Kidd
- Centre for Statistical Consultation, Stellenbosch University, South Africa
| | - Rajiv T Erasmus
- Division of Chemical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Nerina C van der Merwe
- Division of Human Genetics, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa
- Division of Human Genetics, National Health Laboratory Service, Universitas Hospital, Bloemfontein, South Africa
| | - Maritha J Kotze
- Division of Chemical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
- Division of Chemical Pathology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University and the National Health Laboratory Service, Tygerberg Hospital, Cape Town, South Africa
| |
Collapse
|
5
|
25-Hydroxyvitamin D Plasma Levels in Natural Populations of Pigmented and Partially Pigmented Land Iguanas from Galápagos (Conolophus spp.). BIOMED RESEARCH INTERNATIONAL 2022; 2022:7741397. [PMID: 35872852 PMCID: PMC9303120 DOI: 10.1155/2022/7741397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/25/2022] [Indexed: 11/17/2022]
Abstract
We report the first data on 25-hydroxyvitamin D plasma levels in natural populations of three species of land iguana endemic to the Galápagos Islands (Conolophus marthae, C. subcristatus, and C. pallidus). The pigment is present throughout the whole body in the skin of C. subcristatus and C. pallidus. On the contrary, pigment is not present in the skin of an extended part of the body in C. marthae. The only existing population of C. marthae is syntopic with a population of C. subcristatus, and the two species are closely related. These circumstances would suggest that, under the assumption that the species show a similar basking behavior and in the absence of compensatory mechanisms, lighter pigmentation should favor higher vitamin D levels. Thus, C. marthae, compared with C. subcristatus in Wolf Volcano, could show higher levels of 25(OH)D plasma levels, or equal, if compensatory mechanisms exist. The three species showed levels in the range of average values for healthy iguanas. However, contrary to the expectation, C. marthae consistently exhibited the lowest 25(OH)D plasma levels. We discuss possible factors affecting vitamin concentration and hypothesize that C. marthae may use the habitat to limit exposure to the high UVB irradiation at Wolf Volcano.
Collapse
|
6
|
Indian Academy of Pediatrics Revised (2021) Guidelines on Prevention and Treatment of Vitamin D Deficiency and Rickets. Indian Pediatr 2021. [DOI: 10.1007/s13312-022-2448-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
7
|
Abstract
PURPOSE OF REVIEW Vitamin D and folate promote vascular endothelial health and may therefore help mitigate the development of cardiovascular disease (CVD). Ultraviolet radiation (UVR) exposure stimulates cutaneous vitamin D synthesis but degrades the bioactive metabolite of folate, 5-methyltetrahydrofolate (5-MTHF). Skin melanin absorbs UVR, thereby modulating the impact of UVR exposure on vitamin D and 5-MTHF metabolism. This review presents recent findings regarding the inter-relations among UVR, skin pigmentation, folate and vitamin D, and endothelial function. RECENT FINDINGS Evidence for roles of folic acid or vitamin D supplementation on CVD endpoints is inconsistent, although preclinical and clinical studies have demonstrated the efficacy of both micronutrients for improving endothelial function. Vitamin D deficiency is most prevalent in darkly pigmented individuals living in relatively low-UVR environments. Conversely, there is a negative relation between accumulated UVR exposure and serum folate concentration in lightly pigmented adults. The interactions among UVR and bioavailable folate and vitamin D differentially impact endothelial function in differently pigmented skin. SUMMARY UVR exposure disparately impacts folate and vitamin D metabolism in differently pigmented skin depending upon regional UVR intensity and seasonality. These findings present new clinical research questions regarding the interactions among UVR, skin pigmentation, folate and vitamin D bioavailability, and endothelial health.
Collapse
Affiliation(s)
| | - W. Larry Kenney
- Department of Kinesiology
- Graduate Program in Physiology, The Pennsylvania State University, University Park, PA, USA
| |
Collapse
|
8
|
Datta P, Philipsen PA, Idorn LW, Wulf HC. Low vitamin D in dark-skinned immigrants is mainly due to clothing habits and low UVR exposure: a Danish observational study. Photochem Photobiol Sci 2021; 20:1573-1584. [PMID: 34718967 DOI: 10.1007/s43630-021-00115-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 10/11/2021] [Indexed: 10/19/2022]
Abstract
Low 25-hydroxyvitamin D3 (25(OH)D) among dark-pigmented persons has been observed. To elucidate the reason for this we examined sun behaviour, sun-exposed body area, solar UVR exposure and 25(OH)D levels in immigrants with dark pigmented skin and Danes with light pigmented skin. Clothing, sun behaviour, and diet were recorded daily during a Danish summer season (93 analysed days). Erythema-weighted UVR doses were measured by personal electronic UVR dosimeters (with erythema response, measurement every 5th second) and 25(OH)D was measured in 72 participants (33 dark-skinned and 39 light-skinned). The immigrants exposed 28% less skin area, received 70% less UVR dose, and had 71% less 25(OH)D increase during the summer. The UVR reactivity (Δ25(OH)D per joule accumulated UVR dose) was similar (P = 0.62) among the immigrants (0.53 nmol l-1 J-1) and the Danes (0.63 nmol l-1 J-1). In the groups combined, 25(OH)D levels after summer were mainly influenced by UVR dose to exposed skin (28.8%) and 25(OH)D start level (27.9%). Height and measured constitutive skin pigmentation were of minor influence: 3.5% and 3.2%, respectively. Sun exposure and clothing habits were the main reasons for lower 25(OH)D level after summer in the darker immigrants, as both groups had similar UVR reactivity.
Collapse
Affiliation(s)
- Pameli Datta
- Department of Dermatology D92, Bispebjerg Hospital, University of Copenhagen, Nielsine Nielsens Vej 17, 2400, Copenhagen NV, Denmark.
| | - Peter Alshede Philipsen
- Department of Dermatology D92, Bispebjerg Hospital, University of Copenhagen, Nielsine Nielsens Vej 17, 2400, Copenhagen NV, Denmark
| | - Luise Winkel Idorn
- Department of Dermatology D92, Bispebjerg Hospital, University of Copenhagen, Nielsine Nielsens Vej 17, 2400, Copenhagen NV, Denmark
| | - Hans Christian Wulf
- Department of Dermatology D92, Bispebjerg Hospital, University of Copenhagen, Nielsine Nielsens Vej 17, 2400, Copenhagen NV, Denmark
| |
Collapse
|
9
|
A revised action spectrum for vitamin D synthesis by suberythemal UV radiation exposure in humans in vivo. Proc Natl Acad Sci U S A 2021; 118:2015867118. [PMID: 34580202 PMCID: PMC8501902 DOI: 10.1073/pnas.2015867118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2021] [Indexed: 11/24/2022] Open
Abstract
Solar UV radiation (UVR) causes sunburn but initiates the first step of vitamin D synthesis, which is the formation of previtamin D3 (pre-D3) in skin. The gold standard for assessing vitamin D is serum 25-hydroxyvitamin D3 [25(OH)D3]. Public health advice for optimal solar exposure requires UVR wavelength-dependence (action spectrum) data on risks and benefits. An action spectrum for pre-D3 in human ex vivo skin was established over 30 y ago, but its validity has been questioned. We tested this action spectrum in healthy volunteers using serum 25(OH)D3 as the endpoint. Our analysis shows that the pre-D3 action spectrum can be improved with a systematic correction. This will result in better risk–benefit calculations for public health advice on solar exposure. Action spectra are important biological weighting functions for risk/benefit analyses of ultraviolet (UV) radiation (UVR) exposure. One important human benefit of exposure to terrestrial solar UVB radiation (∼295 to 315 nm) is the cutaneous synthesis of vitamin D3 that is initiated by the photoconversion of 7-dehydrocholesterol to previtamin D3. An action spectrum for this process that is followed by other nonphotochemical steps to achieve biologically active vitamin D3 has been established from ex vivo data and is widely used, although its validity has been questioned. We tested this action spectrum in vivo by full- or partial-body suberythemal irradiation of 75 healthy young volunteers with five different polychromatic UVR spectra on five serial occasions. Serum 25-hydroxyvitamin D3 [25(OH)D3] levels, as the most accurate measure of vitamin D3 status, were assessed before, during, and after the exposures. These were then used to generate linear dose–response curves that were different for each UVR spectrum. It was established that the previtamin D3 action spectrum was not valid when related to the serum 25(OH)D3 levels, as weighting the UVR doses with this action spectrum did not result in a common regression line unless it was adjusted by a blue shift, with 5 nm giving the best fit. Such a blue shift is in accord with the published in vitro action spectra for vitamin D3 synthesis. Thus, calculations regarding the risk (typically erythema) versus the benefit of exposure to solar UVR based on the ex vivo previtamin D3 action spectrum require revision.
Collapse
|
10
|
Neville JJ, Palmieri T, Young AR. Physical Determinants of Vitamin D Photosynthesis: A Review. JBMR Plus 2021; 5:e10460. [PMID: 33553995 PMCID: PMC7839826 DOI: 10.1002/jbm4.10460] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 12/18/2022] Open
Abstract
Vitamin D synthesis by exposure of skin to solar ultraviolet radiation (UVR) provides the majority of this hormone that is essential for bone development and maintenance but may be important for many other health outcomes. This process, which is the only well-established benefit of solar UVR exposure, depends on many factors including genetics, age, health, and behavior. However, the most important factor is the quantity and quality of UVR reaching the skin. Vitamin D synthesis specifically requires ultraviolet B (UVB) radiation that is the minority component (<5%) of solar UVR. This waveband is also the most important for the adverse effects of solar exposure. The most obvious of which is sunburn (erythema), but UVB is also the main cause of DNA damage to the skin that is a prerequisite for most skin cancers. UVB at the Earth's surface depends on many physical and temporal factors such as latitude, altitude, season, and weather. Personal, cultural, and behavioral factors are also important. These include skin melanin, clothing, body surface area exposed, holiday habits, and sunscreen use. There is considerable disagreement in the literature about the role of some of these factors, possibly because some studies have been done by researchers with little understanding of photobiology. It can be argued that vitamin D supplementation obviates the need for solar exposure, but many studies have shown little benefit from this approach for a wide range of health outcomes. There is also increasing evidence that such exposure offers health benefits independently of vitamin D: the most important of which is blood-pressure reduction. In any case, public health advice must optimize risk versus benefit for solar exposure. It is fortunate that the individual UVB doses necessary for maintaining optimal vitamin D status are lower than those for sunburn, irrespective of skin melanin. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Jonathan J Neville
- St John's Institute of Dermatology, School of Basic & Medical Biosciences King's College London London United Kingdom
| | - Tommaso Palmieri
- St John's Institute of Dermatology, School of Basic & Medical Biosciences King's College London London United Kingdom
| | - Antony R Young
- St John's Institute of Dermatology, School of Basic & Medical Biosciences King's College London London United Kingdom
| |
Collapse
|
11
|
Hawk JLM. Safe, mild ultraviolet-B exposure: An essential human requirement for vitamin D and other vital bodily parameter adequacy: A review. PHOTODERMATOLOGY PHOTOIMMUNOLOGY & PHOTOMEDICINE 2020; 36:417-423. [PMID: 32623756 PMCID: PMC7754393 DOI: 10.1111/phpp.12584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/13/2020] [Accepted: 06/28/2020] [Indexed: 12/12/2022]
Abstract
The enigma of skin sunburning, skin ageing and skin cancer and essential vitamin D production both resulting from solar ultraviolet‐B (280‐315 nm) (UVB) exposure has long puzzled photobiologists. Advice to patients by non‐photobiological clinicians is now often to sunbathe to acquire vitamin D adequacy. However, modern work shows only mild UVB exposure is needed to maintain satisfactory levels, which have been demonstrated as very similar in summer and winter from about 25° to 70° north. Even very careful high protection factor 15 sunscreen use does not prevent adequate production, although it is slightly reduced, such that obsessive use of very protective screens of 50 + might. Dark skin pigmentation too usually at most minimally impairs production. However, confinement indoors and widespread clothing cover can, but oral supplementation overcomes any such deficiency. Thus, vitamin D adequacy needs just mild regular UVB skin exposure well under sunburning levels, unlikely to cause significant skin damage. This suggests mild UVB exposure may also be needed for other bodily requirements, which is indeed so. Thus, it also prevents the development of contact dermatitis and polymorphic light eruption through suppressing adaptive immunity. It also prevents the occurrence of multiple skin infections resulting from this suppression through stimulating innate immunity and cutaneous bacterial defensin production. Finally, blood pressure is reduced through low‐dose UVB‐induced production of the vasodilator nitric oxide (though UVA, 315‐400 nm, is more efficient). Thus, mild UVB exposure is important for several aspects of internal health, whereas high‐dose exposure is extremely detrimental to cutaneous health.
Collapse
Affiliation(s)
- J L M Hawk
- Emeritus Professor of Dermatological Photobiology, Photodermatology Unit, St John's Institute of Dermatology, King's College London, London, UK
| |
Collapse
|
12
|
Rivera-Paredez B, Hidalgo-Bravo A, de la Cruz-Montoya A, Martínez-Aguilar MM, Ramírez-Salazar EG, Flores M, Quezada-Sánchez AD, Ramírez-Palacios P, Cid M, Martínez-Hernández A, Orozco L, Denova-Gutiérrez E, Salmerón J, Velázquez-Cruz R. Association between vitamin D deficiency and common variants of Vitamin D binding protein gene among Mexican Mestizo and indigenous postmenopausal women. J Endocrinol Invest 2020; 43:935-946. [PMID: 31907821 DOI: 10.1007/s40618-019-01177-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/30/2019] [Indexed: 12/13/2022]
Abstract
PURPOSE Vitamin D deficiency (VDD) and polymorphisms in the group-specific component (GC) gene are known to be associated in different populations. However, the effects of such genetic variants may vary across different populations. Thus, the objective of this study was to estimate the association between Vitamin D-Binding Protein (VDBP) haplotypes and VDD in mestizo postmenopausal women and Mexican Amerindian ethnic groups. METHODS This was a cross-sectional study of 726 postmenopausal Mexican women from the Health Workers Cohort Study (HWCS) and 166 postmenopausal women from the Metabolic Analysis in an Indigenous Sample (MAIS) cohort in Mexico. GC polymorphisms (rs7045 and rs4588) were analyzed by TaqMan probes. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured by Chemiluminescent Microparticle Immuno Assay. RESULTS The prevalence of VDD serum 25(OH)D < 20 ng/mL was 43.7% in mestizo women and 44.6% in indigenous women. In HWCS, the single nucleotide polymorphisms (SNPs) rs7041 and rs4588 were associated with VDD. In addition, women from the HWCS, carrying the haplotypes GC2/2 and GC1f/2 had higher odds of VDD (OR = 2.83, 95% CI 1.14, 7.02; and OR = 2.30, 95% CI 1.40, 3.78, respectively) compared to women with haplotype 1f/1 s. These associations were not statistically significant in the MAIS cohort. CONCLUSIONS Our results show genetic association of the analyzed SNPs and related haplotypes, on the GC gene, with VDD in mestizo Mexican postmenopausal women. Moreover, a high prevalence of VDD with high genetic variability within the country was observed. Our results support the need for national policies for preventing VDD.
Collapse
Affiliation(s)
- B Rivera-Paredez
- Centro de Investigación en Políticas, Población Y Salud de La Facultad de Medicina de La Universidad Nacional Autónoma de México, Ciudad de México, México
| | - A Hidalgo-Bravo
- Departamento de Genética, Instituto Nacional de Rehabilitación, Ciudad de México, México
| | - A de la Cruz-Montoya
- Laboratorio de Genómica del Metabolismo Óseo, Instituto Nacional de Medicina Genómica (INMEGEN), Ciudad de México, México
| | - M M Martínez-Aguilar
- Laboratorio de Genómica del Metabolismo Óseo, Instituto Nacional de Medicina Genómica (INMEGEN), Ciudad de México, México
| | - E G Ramírez-Salazar
- CONACYT-Laboratorio de Genómica del Metabolismo Óseo, (INMEGEN), Ciudad de México, México
| | - M Flores
- Centro de Investigación en Nutrición y Salud, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
| | - A D Quezada-Sánchez
- Centro de Información Para Decisiones en Salud Pública, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
| | - P Ramírez-Palacios
- Unidad de Investigación Epidemiológica Y en Servicios de Salud, Instituto Mexicano del Seguro Social (IMSS), Delegación Morelos, Cuernavaca, México
| | - M Cid
- Laboratorio de Inmunogenómica Y Enfermedades Metabólicas Instituto Nacional de Medicina Genómica (INMEGEN), Ciudad de México, México
| | - A Martínez-Hernández
- Laboratorio de Inmunogenómica Y Enfermedades Metabólicas Instituto Nacional de Medicina Genómica (INMEGEN), Ciudad de México, México
| | - L Orozco
- Laboratorio de Inmunogenómica Y Enfermedades Metabólicas Instituto Nacional de Medicina Genómica (INMEGEN), Ciudad de México, México
| | - E Denova-Gutiérrez
- Centro de Investigación en Nutrición y Salud, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
| | - J Salmerón
- Centro de Investigación en Políticas, Población Y Salud de La Facultad de Medicina de La Universidad Nacional Autónoma de México, Ciudad de México, México
| | - R Velázquez-Cruz
- Laboratorio de Genómica del Metabolismo Óseo, Instituto Nacional de Medicina Genómica (INMEGEN), Ciudad de México, México.
| |
Collapse
|
13
|
Young AR, Morgan KA, Ho TW, Ojimba N, Harrison GI, Lawrence KP, Jakharia-Shah N, Wulf HC, Cruickshank JK, Philipsen PA. Melanin has a Small Inhibitory Effect on Cutaneous Vitamin D Synthesis: A Comparison of Extreme Phenotypes. J Invest Dermatol 2019; 140:1418-1426.e1. [PMID: 31883961 DOI: 10.1016/j.jid.2019.11.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 11/22/2019] [Accepted: 11/25/2019] [Indexed: 01/04/2023]
Abstract
Epidemiology suggests that melanin inhibits cutaneous vitamin D3 synthesis by UVR. Laboratory investigations assessing the impact of melanin on vitamin D production have produced contradictory results. We determined the effect of melanin on vitamin D3 photosynthesis in healthy young volunteers (n = 102) of Fitzpatrick skin types II-VI (white to black). Participants, irrespective of skin type, were exposed to the same suberythemal UVR dose, to 85% body surface area, using solar simulated UVR or narrowband UVB (311 nm). This was repeated five times with intervals of 3-4 days between UVR exposures. Blood was taken before, during, and after the irradiation and assessed for serum 25-hydroxyvitamin D3 (25[OH]D3) as a marker of vitamin D3 status. Linear UVR dose-dependent increases in 25(OH)D3 were highly significant (P ≤ 7.7 x 10-11). The ratios of regression slopes of the different skin type groups were compared, and only skin type II was significantly steeper than the other groups. Comparisons between extreme skin types II and VI showed melanin inhibition factors of approximately 1.3-1.4, depending on the UVR source. We conclude that the inhibitory effect of melanin on vitamin D3 synthesis is small, compared with erythema, but that this difference may be sufficient to explain the epidemiological data.
Collapse
Affiliation(s)
- Antony R Young
- St John's Institute of Dermatology, King's College London, London, United Kingdom.
| | - Kylie A Morgan
- St John's Institute of Dermatology, King's College London, London, United Kingdom
| | - Tak-Wai Ho
- Department of Nutritional Science, Division of Life-Course Sciences, King's College London, London, United Kingdom
| | - Ngozi Ojimba
- Department of Nutritional Science, Division of Life-Course Sciences, King's College London, London, United Kingdom; Dietetics Department, Homerton University Hospital NHS Foundation Trust, London, United Kingdom
| | - Graham I Harrison
- St John's Institute of Dermatology, King's College London, London, United Kingdom
| | - Karl P Lawrence
- St John's Institute of Dermatology, King's College London, London, United Kingdom
| | - Nihull Jakharia-Shah
- St John's Institute of Dermatology, King's College London, London, United Kingdom
| | | | - J Kennedy Cruickshank
- Department of Nutritional Science, Division of Life-Course Sciences, King's College London, London, United Kingdom
| | - Peter A Philipsen
- Department of Dermatology D92, Bispebjerg Hospital, Copenhagen, Denmark
| |
Collapse
|
14
|
Datta P, Philipsen PA, Olsen P, Andersen JD, Morling N, Wulf HC. Serum 25(OH)D levels after oral vitamin D 3 supplementation and UVB exposure correlate. PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE 2019; 35:344-353. [PMID: 31166629 DOI: 10.1111/phpp.12491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 04/26/2019] [Accepted: 06/02/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND The inter-individual variation in 25(OH)D3 increase (Δ25(OH)D3 ) after vitamin D3 supplementation was determined and compared with the UVB irradiation response. METHODS Nineteen Danish participants received 85 μg vitamin D3 (cholecalciferol) daily for nine weeks with regular serum 25(OH)D3 measurements. These participants had three years earlier taken part in a 9-week controlled UVB study. The Δ25(OH)D3 was not confounded by ambient UVB, BMI or ethnicity. RESULTS Δ25(OH)D3 was 53 nmol L-1 and almost identical to Δ25(OH)D3 (52 nmol L-1 ) after UVB. Δ25(OH)D3 ranged from 17 to 91 nmol L-1 (span 74 nmol L-1 ) and was about half of that observed after UVB irradiation (span 136 nmol L-1 ). The interquartile ranges for vitamin D3 supplementation (38.8-71.4 nmol L-1 , span: 32.6 nmol L-1 ) and UVB irradiation (35.7-65.4 nmol L-1 , span: 29.7 nmol L-1 ) were similar indicating a comparable response of the two interventions. As the 25(OH)D3 start levels (R2 = 0.398, P = 3.8 × 10-3 ), 25(OH)D3 end levels (R2 = 0.457, P = 1.5 × 10-3 ) and Δ25(OH)D3 (R2 = 0.253, P = 0.028) between both interventions were correlated, this suggested a possible common individual background for the variation. Four pigment SNPs influenced the variation in the vitamin D3 -induced and UVB-induced Δ25(OH)D3 . A combined model including the influence of these four SNPs and the 25(OH)D3 start level explained 86.8% (P = 1.6 × 10-35 ) of the individual variation after vitamin D3 supplementation. CONCLUSION The inter-individual variation in the two interventions was comparable and had no common demographic but a partly common genetic background.
Collapse
Affiliation(s)
- Pameli Datta
- Department of Dermatology D92, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark
| | - Peter Alshede Philipsen
- Department of Dermatology D92, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark
| | - Peter Olsen
- Department of Dermatology D92, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark
| | - Jeppe Dyrberg Andersen
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Niels Morling
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hans Christian Wulf
- Department of Dermatology D92, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark
| |
Collapse
|
15
|
Wolf ST, Kenney WL. The vitamin D-folate hypothesis in human vascular health. Am J Physiol Regul Integr Comp Physiol 2019; 317:R491-R501. [PMID: 31314544 DOI: 10.1152/ajpregu.00136.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The vitamin D-folate hypothesis has been proposed as an explanation for the evolution of human skin pigmentation. According to this hypothesis, a darkened skin pigment was adapted by early human populations living in equatorial Africa to protect against photodegradation of bioavailable folate by ultraviolet radiation (UVR). As humans moved away from the equator to more northern latitudes and occupied regions of lower UVR exposure and greater seasonal variation, however, depigmentation occurred to allow for adequate biosynthesis of vitamin D. Vitamin D and folate are both recognized for their evolutionary importance in healthy pregnancy and early childhood development. More recently, evidence has emerged demonstrating the importance of both vitamin D and folate in vascular health via their effects in reducing oxidative stress and improving nitric oxide (NO) bioavailability. Thus, populations with darkened skin pigmentation may be at elevated risk of vascular dysfunction and cardiovascular disease in low UVR environments due to hypovitaminosis D; particularly important as darkly-pigmented African-Americans represent an at-risk population for cardiovascular disease. Conversely, lightly pigmented populations in high UVR environments may be at risk of deleterious vascular effects of UVR-induced folate degradation. The focus of this review is to explore the currently available literature regarding the potential role of UVR in vascular health via its differential effects on vitamin D and folate metabolism, as well as the interaction between skin pigmentation, genetics, and environment in modulating the vascular influence of UVR exposure.
Collapse
Affiliation(s)
- S Tony Wolf
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania
| | - W Larry Kenney
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.,Graduate Program in Physiology, The Pennsylvania State University, University Park, Pennsylvania
| |
Collapse
|