Vitamin D Synthesis Following a Single Bout of Sun Exposure in Older and Younger Men and Women

Older adults are frequently cited as an at-risk population for vitamin D deficiency that may in part be due to decreased cutaneous synthesis, a potentially important source of cholecalciferol (vitamin D3). Previous studies found that cutaneous D3 production declines with age; however, most studies have been conducted ex vivo or in the photobiology lab. The purpose of this study was to characterize the response of vitamin D metabolites following a 30-min bout of sun exposure (15-min each to the dorsal and ventral sides) at close to solar noon in younger and older adults. Methods: 30 healthy individuals with skin type II/III were recruited; a younger cohort, aged 20–37 (n = 18) and an older cohort (n = 12), age 51–69 years. Exposure was at outer limits of sensible sun exposure designed to enhance vitamin D synthesis without increasing risk of photo ageing and non-melanoma skin cancer. Serum D3 concentration was measured at baseline, 24, 48 and 72 h post-exposure. Serum 25(OH)D was measured at baseline and 72 h post-exposure plus 168 h post-exposure in the older cohort. Results: D3 increased in response to sun exposure (time effect; p = 0.002) with a trend for a difference in D3 between cohorts (time*group; p = 0.09). By regression modeling of continuous data, age accounted for 20% of the variation in D3 production. D3 production decreased by 13% per decade. Despite changes in D3, however, serum 25(OH)D did not change from baseline to 72 or 168 h post exposure (p > 0.10). Conclusions: Serum D3 concentration increased significantly in response to outdoor sun exposure in younger and older adults. While ageing may dampen cutaneous synthesis, sunlight exposure is still a significant source of vitamin D3.

Association between solar ultraviolet doses and vitamin D clinical routine data in European mid-latitude population between 2006 and 2018

The major source of vitamin D in humans is the ultraviolet radiation-dependent cutaneous synthesis of cholecalciferol; however, low vitamin D status is common in Europe even at mid-latitudes.

Challenge and perspective: the relevance of ultraviolet (UV) radiation and the vitamin D endocrine system (VDES) for psoriasis and other inflammatory skin diseases

Focussing on the UV induced cutaneous synthesis of vitamin D, this review gives an update on the relevance of the VDES and of UV radiation for the management of psoriasis and other inflammatory skin diseases.

Sunshine and vitamin D

Vitamin D is vital for bone health and its deficiency deemed as a disease of the past has re-emerged as an important health concern. Exposure of the skin to solar ultraviolet B radiation is the major source of vitamin D and only a small proportion is derived from dietary intake. We review the various factors that influence the cutaneous synthesis of vitamin D and the recommendations regarding safe sun exposure and dietary supplementation to achieve adequate vitamin D levels proposed for optimal bone health.

Controversies regarding the relation between solar radiation, cutaneous synthesis of vitamin D and the development of malignant melanoma

The relation between sun exposure, vitamin D synthesis and skin cancer is a complex one. Radiations from the sun stimulate the cutaneous vitamin D synthesis, one way, and promote the development of the skin cancer on the other way. A lot of epidemiologic and experimental studies revealed contradictory results regarding the relation between vitamin D and malignant melanoma. The vitamin D deficiency, accurate biochemical indicator of the vitamin D status in the body, could be implicated in promoting metastasis of the malignant melanoma by activation of the cellular proliferation, stimulation of the neutrophils chemotaxis and promoting angiogenesis. Identification of therapeutic strategies to normalise serum levels of the 25-OH vitamin D3 could represent useful tools in preventing melanoma metastasis.

Repair of cutaneous wounds with the use of low cost surgical glue

BACKGROUND: The advantages of the cyanoacrylates in cutaneous synthesis have been often demonstrated in the literature. However, these products have been underutilized in Brazil due to the high costs of the 2-octil-cyanoacrylate. Besides, few studies have been done with the more economically accessible form, the 2-etil-cyanoacrylate, as a cutaneous tissue adhesive. OBJECTIVE: To evaluate the effectiveness of the closing of cutaneous lesions using ECA. METHOD: This was a prospective study in which 46 wounds were occluded using the low cost ECA as an alternative to intradermal suture. RESULTS: Excisions (97,8%) and traumatic wounds (2,2%) were treated with 2-etil-cyanoacrylate and deep relaxed sutures as synthesis method. Unaesthetic scars (22%), infection (2,1%), dehiscence (2,1%) and contact allergic dermatitis (2,1%) were the problems we found. There were no cases of necrosis or keloids. The results were considered satisfactory in most cases (97,3%). CONCLUSION: The use of 2-etil-cyanoacrylate was shown to be safe and with satisfactory cosmetic results in this group of patients.

Traditionally living populations in East Africa have a mean serum 25-hydroxyvitamin D concentration of 115 nmol/l

Cutaneous synthesis of vitamin D by exposure to UVB is the principal source of vitamin D in the human body. Our current clothing habits and reduced time spent outdoors put us at risk of many insufficiency-related diseases that are associated with calcaemic and non-calcaemic functions of vitamin D. Populations with traditional lifestyles having lifelong, year-round exposure to tropical sunlight might provide us with information on optimal vitamin D status from an evolutionary perspective. We measured the sum of serum 25-hydroxyvitamin D2 and D3 (25(OH)D) concentrations of thirty-five pastoral Maasai (34 (sd 10) years, 43 % male) and twenty-five Hadzabe hunter–gatherers (35 (sd 12) years, 84 % male) living in Tanzania. They have skin type VI, have a moderate degree of clothing, spend the major part of the day outdoors, but avoid direct exposure to sunlight when possible. Their 25(OH)D concentrations were measured by liquid chromatography–MS/MS. The mean serum 25(OH)D concentrations of Maasai and Hadzabe were 119 (range 58–167) and 109 (range 71–171) nmol/l, respectively. These concentrations were not related to age, sex or BMI. People with traditional lifestyles, living in the cradle of mankind, have a mean circulating 25(OH)D concentration of 115 nmol/l. Whether this concentration is optimal under the conditions of the current Western lifestyle is uncertain, and should as a possible target be investigated with concomitant appreciation of other important factors in Ca homeostasis that we have changed since the agricultural revolution.