Study: Is avoiding sunlight fatal?

Reference

Design

participant

study parameters

1. Do you take sunbathing in summer? (never, 1–14 times, 15–30 times or> 30 times)
2. Do you take sunbathing in winter, for example on vacation in the mountains? (No, 1–3 days, 4–10 days or> 10 days)
3. Do you use solariums? (never, 1–3 times a year, 4–10 times a year or> 10 times a year)
4. Do you drive abroad on vacation to swim and sunbathe? (never, once every 1-2 years, once a year, ≥2 times a year).

primary result dimensions

Influence of sunlight on the overall mortality, the risk of melanoma and the melano death rate

most important knowledge

A total of 2,545 deaths. The overall mortality was in the opposite connection with the sun exposure habits. The mortality rate for sun detection was about twice as high (Hazard Ratio). [HR]: 2.0, 95 %confidence interval [CI]: 1.6-2.5) compared to the group with the highest solar exposure. People with moderate exposure had a 40 % increased risk of mortality (HR: 1.4, 95 %-KI: 1.1–1.7). Women with "normal" sun exposure habits had no significantly increased risk of melanoma or melanoma -related deaths.

effects on practice

It is not surprising that the authors found that avoiding sunlight is a risk factor for the total mortality. This states in accordance with the increasing evidence that a vitamin D deficiency is associated with an increased risk of death due to cardiovascular diseases ^{1 and cancer. 2 The authors came to the conclusion that a limitation of sun rays in countries with low sun intensity (e.g. Sweden) could harm the health of women, allegedly the endogenous production of vitamin D would be reduced.}
The non -limitation of the sun's rays is a way to increase vitamin D, but not the most reliable method. In my opinion, a better expansion of the conclusion of the authors would have been a recommendation to take vitamin D nutritional supplements to ensure a vitamin D mirror, which is associated with a lower risk of cardiovascular diseases, cancer and melanomas in particular. UV protection (UV protection) is desirable for many reasons, including reducing the risk of non-melanocytic skin cancer and skin aging. It can be achieved best by avoiding the sun's rays at noon and applying physical full spectrum sun protection (and applying again if necessary), e.g. Non-nanoparticles containing zinc or titanium as well as the wearing of light UV protective clothing such as hats, long sleeves and long pants with a UV protection factor (UPF) of 15 or more.
The non -limitation of the sunlight is a way to increase vitamin D, but not the most reliable method.
on the assumption that UV radiation is the main cause of melanomas and that low vitamin D levels are associated with thicker, more aggressive melanoma with shorter survival times, 3 The authors assume that opposite mechanisms could have a effect on the risk of melanoma and the avoidance of UV exposure. The active metabolite of vitamin D- 1.25 (oh) 2 It has been shown that the anti-cancer effects, such as: B. a standstill of the cell cycle, the induction of apoptosis and the inhibition of proliferation.
In addition, the study design has several defects. For example, the study team categorized regular physical activities in three groups: none, at least once a week, or strenuous physical activity - weak definitions with serious restrictions. The four questions asked the participants of this study on solar exposure are perhaps the most serious weakness in their design. The definition of solar exposure as sunbathing and solarium is a very limited and questionable measure. Many people are exposed to the sun through physical activities outdoors such as walking, hiking, cycling or camping or even outdoor employment. The authors also assumed that the sun habits did not change during the 20-year study. It also suggests that women with “normal” sun exposure habits (not defined by the authors) had no significantly increased risk of melanoma or melanoma -related deaths is that the method for measuring solar exposure habits in this study was incorrect, since the there are very strong evidence of an increased risk of melanoma through repeated overexposition UV radiation. ⁵
The authors of this study must be recognized that their "results are coherent and not necessarily causal" and that "additional evidence and possibly other study designs are necessary to draw causal conclusions". They even recognize that there is no data on vitamin D supplementation or vitamin D levels in the study, and only indicate that "sunlight is the most important factor for vitamin D status". However, this claim may be true for the population that was recruited for their study 20 years ago, but is probably no longer correct today, since today a large number of people take vitamin D supplements in doses that may exceed the endogenous doses.
1. Schneider Al, Michos Ed. Invited comment: The connection between low vitamin D content and cardiovascular diseases-to get the "heart and soul" of the relationship in a nutshell. am j epidemiol. 2014; 179 (11): 1288-1290.
2. Feldman D, Krishnan AV, Swami S, Giovannucci e, Feldman Bj. The role of vitamin D in reducing cancer risk and cancer progression. Nat Rev Krebs. 2014; 14 (5): 342-357.
3. Gambichler T, Bindsteiner M, Höxtermann S, Kreuter A. Serum-25-Hydroxyvitamin D serum mirror in a large German cohort of patients with melanoma. br j dermatol. 2013; 168 (3): 625-628.
4. luong k, nguyen lt. The advantageous role of vitamin D and its analogue in cancer treatment and prevention. crit revol hematol. 2009; 73 (3): 192-201.
5. Usher-Smith Yes, Emery J, Kassianos AP, Walter FM. Risk forecast models for melanomas: a systematic review. Krebs epidemiol-biomarker before. June 3, 2014. Epub before printing.