From the Academy

Sunlight, tanning booths, and vitamin D

The objective of this study was to collect prevalence estimates of indoor tanning usage and associated injuries in Canada. The rapid response component of the 2019 Canadian Community Health Survey collected data on the use of tanning equipment in the previous 12 months, including reasons for use, frequency/duration of use, precautions taken and adverse reactions or injuries.

The 2019 research findings were as follows, an estimated 3.0% (95% CI: 2.5–3.4%) of Canadians reported that they had used indoor tanning equipment in the past year. Among users, 71.1% (95% CI: 63.9–78.3%) were female and females aged 18–34 were significantly more prevalent users compared to females aged 45 or older. The prevalence of indoor tanning was higher among people without a university degree; however, there were no differences in prevalence by household income or region. Most users indicated they used indoor tanning equipment within a tanning salon (75.3%: 95% CI: 69.1–81.6%) and the most common reason for usage was to develop a “protective” base tan (72.1%: 95% CI: 65.2–78.9%). Over one third (39.2%: 95% CI: 31.1–47.2%) of all users reported 10 or more sessions in the past year.

The prevalence of indoor UV tanning usage is declining in Canada. Similar to results in 2014, the majority of users continue to be female, with a large number in the 18 to 34 age group.

Cutaneous photobiology studies have focused primarily on the ultraviolet portion of the solar spectrum. Visible light (VL), which comprises 50% of the electromagnetic radiation that reaches the Earth's surface and, as discussed in Part I of this CME, has cutaneous biologic effects, such as pigment darkening and erythema. Photoprotection against VL includes avoiding the sun, seeking shade, and using photoprotective clothing. The organic and inorganic ultraviolet filters used in sunscreens do not protect against VL, only tinted sunscreens do. In the United States, these filters are regulated by the Food and Drug Administration as an over-the-counter drug and are subject to more stringent regulations than in Europe, Asia, and Australia. There are no established guidelines regarding VL photoprotection. Alternative measures to confer VL photoprotection are being explored. These novel methods include topical, oral, and subcutaneous agents. Further development should focus on better protection in the ultraviolet A1 (340-400 nm) and VL ranges while enhancing the cosmesis of the final products.

The purpose of the chapter is to view vitamin D in the context of sport nutrition and its vital role in enhancing athletic performance. The chapter focuses on the present understanding of the physiological functions of vitamin D in bone health, musculoskeletal system, and immunity, in addition to the potential impact on athletic performance. Based on the available evidence, retaining the serum 25-hydroxy vitamin D (25(OH)D) concentration above the optimal level (up to 100 nmol/L) increases musculoskeletal function, reduces fracture recovery period from exercise, improves both force as well as power production, and enhances production of testosterone, all of which influence the athletic performance. On the other hand, deficiency of vitamin D can cause numerous health problems, such as increased incidence of bone injuries, stress fracture, prolonged skeletal muscle pain, and respiratory tract illness. In spite of these, large populations of athletes are vitamin D deficient. Regular intake of dietary vitamin D sources alone is not enough to preserve sufficient level of vitamin D. Adequate level of sun exposure and regular supplements of vitamin D or a mixture of dietary intake and sun exposure along with vitamin D supplements are necessary to attain adequate levels vitamin D. Recommendation of vitamin D to each athletes should be individualized based on their serum 25(OH)D level, clinical symptoms, season, and diet. However, intoxication of vitamin D from over consumption of the supplements is unusual. Normally, athletes with insufficient vitamin D status need daily vitamin D supplementation with a minimum of 1500–2000 IU.

We estimated the numbers of cases of health care conditions that are causally associated with exposure to tanning devices in the United States, and calculated the costs of medical care for treating these cases.

The principal unit of analysis for this study is the number of individuals living in the United States who sought treatment for basal cell carcinomas (BCC), squamous cell carcinomas (SCC), or melanomas. To estimate the percentage of these cases that are attributable to exposure to tanning devices, we calculated the Population Attributable Risk (PAR) for each disease. We calculated annual medical costs on a per-case basis as well as indirect productivity costs, using Years of Potential Life Lost.

There were nearly 9000 incident cases of melanoma, and more than 86,600 cases of SCC and 168,000 cases of BCC, attributable to exposure to tanning devices in the U.S. in 2015. The cost of direct medical care for these cases is $343.1 million annually, and they will lead to a total economic loss of $127.3 billion over the lifetime of the individuals affected.

The use of tanning devices is a significant contributor to illness and premature mortality in the U.S., and also represents a major economic burden in terms of the costs of medical care and lost productivity.

The present work reports the effects of ultraviolet radiation on commercial vermiculites for the first time. The changes induced by UV-radiation, dehydration–hydration and structural order–disorder, were studied by using X-ray diffraction (XRD). The results of XRD analysis indicated that these changes occurred in a similar way as temperature and vacuum do and they were more significant for vermiculites in powder form than in thin sheet. The larger crystallite size in the thin samples implied the presence of lower amounts of defects, improvement in the crystallinity and therefore increasing the structural order. Furthermore, ultraviolet radiation, being less penetrating and easier and cheaper to obtain than the gamma radiation, could be used as an alternative to induce structural order in thin sheet vermiculites. This success could be very important to solve some aspects related with the dimensionality of magnetic interactions, which plays a central role in controlling the critical dynamics of spin-glass systems (disordered magnet, where the magnetic spins of the component atoms — the orientation of the north and south magnetic poles in three-dimensional space — are not aligned in a regular pattern), and it is still not resolved in vermiculite due probably to its disordered structure. Also, the ultraviolet radiation as with gamma radiation probably might allow to enhance the physical properties of vermiculite as optoelectronic properties which would make it suitable for optoelectronic devices, although more investigation is needed.

Epidemiologic and preclinical data, and a small randomized trial in Boston, suggest that vitamin D supplementation may improve winter-related atopic dermatitis (AD).

To determine the effect of vitamin D supplementation on winter-related AD.

We performed a randomized, double-blind, placebo-controlled trial of Mongolian children with winter-related AD (clinicaltrials.gov identifier: NCT00879424). Baseline eligibility included age 2 to 17 years, AD score 10 to 72 using the Eczema Area and Severity Index (EASI), and winter-related AD (eg, history of AD worsening during the fall-to-winter transition). Subjects were enrolled in Ulaanbaatar during winter and randomly assigned to oral cholecalciferol (1000 IU/day) versus placebo for 1 month. All children and parents received emollient and patient education about AD and basic skin care. The main outcomes were changes in EASI score and in Investigator's Global Assessment.

The 107 enrolled children had a mean age of 9 years (SD 5), and 59% were male. Their median age of AD onset was 3 months (interquartile range 2 months to 1 year) and mean EASI score at baseline 21 (SD 9). One-month follow-up data were available for 104 (97%) children. Compared with placebo, vitamin D supplementation for 1 month produced a clinically and statistically significant improvement in EASI score (adjusted mean change: −6.5 vs −3.3, respectively; P = .04). Moreover, change in Investigator's Global Assessment favored vitamin D over placebo (P = .03). There were no adverse effects in either group.

Vitamin D supplementation improved winter-related AD among Mongolian children, a population likely to have vitamin D deficiency in winter.