Solar UVB Doses Research Articles

Cancer Incidence Rates in the US in 2016-2020 with Respect to Solar UVB Doses, Diabetes and Obesity Prevalence, Lung Cancer Incidence Rates, and Alcohol Consumption: An Ecological Study.

This article reports the results of an ecological study of cancer incidence rates by state in the US for the period 2016-2020. The goals of this study were to determine the extent to which solar UVB doses reduced cancer risk compared to findings reported in 2006 for cancer mortality rates for the periods 1950-1969 and 1970-1794 as well as cancer incidence rates for the period 1998-2002 and to determine which factors were recently associated with cancer risk. The cancer data for non-Hispanic white (European American) men and women were obtained from the Centers for Disease Control and Prevention. Indices were obtained for solar UVB at the surface for July 1992, and alcohol consumption, diabetes, and obesity prevalence near the 2016-2020 period. Lung cancer incidence rates were also used in the analyses as a surrogate for smoking, diet, and air pollution. The cancers for which solar UVB is significantly associated with reduced incidence are bladder, brain (males), breast, corpus uteri, esophageal, gastric, non-Hodgkin's lymphoma, pancreatic, and renal cancer. Lung cancer was significantly associated with colorectal, laryngeal, and renal cancer. Diabetes was also significantly associated with breast, liver, and lung cancer. Obesity prevalence was significantly associated with breast, colorectal, and renal cancer. Alcohol consumption was associated with bladder and esophageal cancer. Thus, diet has become a very important driver of cancer incidence rates. The role of solar UVB in reducing the risk of cancer has been reduced due to people spending less time outdoors, wearing sunscreen that blocks UVB but not UVA radiation, and population increases in terms of overweight and obese individuals, which are associated with lower 25-hydroxyvitamin D concentrations and the generation of systemic inflammation, which is a risk factor for cancer. A dietary approach that would reduce the risk of diabetes, obesity, lung cancer, and, therefore, cancer, would be one based mostly on whole plants and restrictions on red and processed meats and ultraprocessed foods. Solar UVB exposure for a few minutes before applying sunscreen and taking vitamin D supplements would also help reduce the risk of cancer.

Vitamin D and Breast Cancer: Latest Evidence and Future Steps.

Vitamin D (the sunshine vitamin) plays a vital role in calcium homeostasis, skeletal metabolism, and immune, cardiovascular, and reproductive systems’ functions. The worldwide prevalence of vitamin D deficiency is approximately 1 billion. Vitamin D deficiency is a serious health problem with numerous health consequences; it is associated with diabetes, rheumatic arthritis, Parkinson, Alzheimer diseases, osteomalacia, osteoporosis, and fractures in adults and cancers. Many reports showed an inverse association between serum vitamin D concentration and incidence of several cancers, including breast, colorectal, kidney, lung, and pancreatic. About 20 different cancers have incidence rates inversely related to solar UV-B doses and serum vitamin D concentration. Considering the rising incidence of breast cancer and high prevalence of vitamin D deficiency, this review aimed to reflect an association between serum vitamin D concentration and breast cancer risk, reveal the link between vitamin D receptor genetic polymorphisms and breast cancer risk, and review the relationship between vitamin D level, breast cancer risk, and prognostic factors such as tumor stage, grade, size, lymph node involvement, and hormone receptor status.

Impact on Vitamin D2, Vitamin D4 and Agaritine in Agaricus bisporus Mushrooms after Artificial and Natural Solar UV Light Exposure.

Commercial mushroom production can expose mushrooms post-harvest to UV light for purposes of vitamin D2 enrichment by converting the naturally occurring provitamin D2 (ergosterol). The objectives of the present study were to artificially simulate solar UV-B doses occurring naturally in Central Europe and to investigate vitamin D2 and vitamin D4 production in sliced Agaricus bisporus (button mushrooms) and to analyse and compare the agaritine content of naturally and artificially UV-irradiated mushrooms. Agaritine was measured for safety aspects even though there is no rationale for a link between UV light exposure and agaritine content. The artificial UV-B dose of 0.53J/cm(2) raised the vitamin D2 content to significantly (P<0.001) higher levels of 67.1±9.9μg/g dry weight (DW) than sun exposure (3.9±0.8μg/g dry DW). We observed a positive correlation between vitamin D4 and vitamin D2 production (r(2)=0.96, P<0.001) after artificial UV irradiation, with vitamin D4 levels ranging from 0 to 20.9μg/g DW. The agaritine content varied widely but remained within normal ranges in all samples. Irrespective of the irradiation source, agaritine dropped dramatically in conjunction with all UV-B doses both artificial and natural solar, probably due to its known instability. The biological action of vitamin D from UV-exposed mushrooms reflects the activity of these two major vitamin D analogues (D2, D4). Vitamin D4 should be analysed and agaritine disregarded in future studies of UV-exposed mushrooms.

The role of geographical ecological studies in identifying diseases linked to UVB exposure and/or vitamin D.

ABSTRACTUsing a variety of approaches, researchers have studied the health effects of solar ultraviolet (UV) radiation exposure and vitamin D. This review compares the contributions from geographical ecological studies with those of observational studies and clinical trials. Health outcomes discussed were based on the author's knowledge and include anaphylaxis/food allergy, atopic dermatitis and eczema, attention deficit hyperactivity disorder, autism, back pain, cancer, dental caries, diabetes mellitus type 1, hypertension, inflammatory bowel disease, lupus, mononucleosis, multiple sclerosis, Parkinson disease, pneumonia, rheumatoid arthritis, and sepsis. Important interactions have taken place between study types; sometimes ecological studies were the first to report an inverse correlation between solar UVB doses and health outcomes such as for cancer, leading to both observational studies and clinical trials. In other cases, ecological studies added to the knowledge base. Many ecological studies include other important risk-modifying factors, thereby minimizing the chance of reporting the wrong link. Laboratory studies of mechanisms generally support the role of vitamin D in the outcomes discussed. Indications exist that for some outcomes, UVB effects may be independent of vitamin D. This paper discusses the concept of the ecological fallacy, noting that it applies to all epidemiological studies.

The maximal cumulative solar UVB dose allowed to maintain healthy and young skin and prevent premature photoaging.

The young facial skin of children with a smooth healthy appearance changes over time to photoaged skin having mottled pigmentation, solar lentigines, wrinkles, dry and rough skin, leathery texture, and benign and malignant tumors after exposure to chronic, repeated solar radiation. The first sign of photoaging in Japanese subjects is usually solar lentigines appearing around 20years of age on the face. Fine wrinkles can then appear after 30years of age, and benign skin tumors, seborrhoeic keratoses, can occur after 35years of age in sun-exposed skin. We theoretically calculated the maximal daily exposure time to solar radiation, which could prevent the development of photoaged skin until 60 and 80years of age, based on published data of personal solar UVB doses in sun-exposed skin. One MED (minimal erythema dose) was determined to be 20mJ/cm(2) , and 200 MED was used as the average yearly dose of Japanese children. Further, we hypothesized that the annual dose of Japanese adults is the same as that of the children. The cumulative UVB dose at 20years of age was thus calculated to be 4000 MED, and 22 MED was used as the maximal daily UVB dose based on data measured in Kobe, located in the central area of Japan. We used the solar UVB dose from 10:00 a.m. to 14:00 p.m. which occupies 60% of the total daily UV dose, to obtain the maximal UVB per hour in a day, and calculated the maximal daily UV exposure time that would delay the onset of solar lentigines until 60 or 80years of age. The mean daily sun exposure time to maintain healthy skin until 80 years of age in the summer was calculated to be 2.54min (0.14 MED) for unprotected skin and 127min with the use of a sunscreen of SPF (sun protection factor) of 50. In this study, we did not evaluate the photoaging effect of UVA radiation, but findings of the adverse effects of UVA radiation on the skin have accumulated in the last decade. Therefore, it will be important to estimate the maximal dose of solar UV radiation to retard the onset of photoaging based on an evaluation of both solar UVB and UVA in the future. Finally, we expect that this study may contribute to keeping Japanese and other types of skin young and healthy by limiting the exposure of the skin to solar radiation outdoors during the day.

Autism prevalence in the United States with respect to solar UV-B doses: An ecological study

Evidence is mounting that vitamin D deficiency is intimately involved in autism. We report on autism prevalence by US state for those aged 6–17 y in 2010 with respect to indices of solar UV-B (UVB) doses. We calculated autism prevalence rates for white, black and Asian Americans by using total prevalence and relative populations of minors for each ethnic group by state. Analyses omit AK and HI (considered extreme cases), WY (no data), along with AZ and ND for black Americans (low numbers) and DC, ME, MT, ND and SD for Asian Americans (low numbers). For white Americans, the regression coefficient for solar UVB doses and autism prevalence ranged from -0.52 in January to -0.57 in October. For black Americans, the regression coefficient for latitude was 0.61, whereas those for solar UVB ranged from -0.55 to -0.61. For Asian Americans, the values for solar UVB ranged from -0.28 to -0.38. The inverse correlation between solar UVB and autism prevalence is similar to that for many types of cancer in the US. The journal literature indicates that adverse effects on fetal brain development during pregnancy due to vitamin D deficiency can explain these findings. However, we cannot rule out a role of vitamin D deficiency in early life. These results add to the evidence that vitamin D deficiency may be an important risk factor for autism and suggest that pregnant women and autistic individuals raise their serum 25-hydroxyvitamin D concentrations above 30 ng/ml.

What is the role of vitamin D in autism?

A growing body of literature suggests that higher serum 25-hydroxyvitamin D [25(OH)D] concentrations, either in utero or in early life, may reduce the risk of autism. For example, an ecological study in the companion paper inversely correlated solar UV-B doses in the United States with prevalence of autism among those aged 6–17 y. That study proposed that vitamin D deficiency during pregnancy could account for this finding, although the findings are also consistent with childhood vitamin D deficiency contributing to the condition. Also, in a recent study, children with autism had lower serum 25(OH)D concentrations than did control subjects (19 vs. 33 ng/ml), despite parents of each group reporting the same amount of sun exposure. The same study found highly significant inverse correlations between 25(OH)D and autism rating scales and between 25(OH)D and levels of an antineuronal antibody. This finding indicates that higher serum 25(OH)D concentrations may reduce the symptoms of established autism. Because activated vitamin D, a secosteroid, upregulates DNA-repair genes, vitamin D deficiency during development may inhibit the repair of de novo DNA mutations in fetuses and infants and thus contribute to risk of autism. Vitamin D might also reduce the risk or severity of autism through its anti-inflammatory actions, antiautoimmune effects, increasing seizure threshold, increasing T-regulatory cells, protecting the mitochondria, and upregulating glutathione, which scavenges oxidative by-products and chelates (captures and excretes) heavy metals. Vitamin D deficiency during pregnancy and childhood is a widespread and growing epidemic.

Space-based estimation of the solar UV-B doses for psoriasis heliotherapy in Poland using OMI data for the period 2005–2011

A UV model is proposed to reconstruct the biologically weighted doses at the ground-level, erythemal, vitamin D3, and antipsoriatic effective doses, based on the space data from the Ozone Monitoring Instrument on board of NASA EOS Aura spacecraft for the period 2005–2011. The model is training using the results of spectral UV measurements carried out at Belsk, Poland. The model outcome is verified using the UV spectra measured at Hradec Kralove, Czech Republic. The model uncertainty is almost the same for all examined action spectra and comparable to that found in earlier studies on differences between the satellite overpasses and ground-based erythemal data. Antipsoriatic doses, taken during 2h exposure periods near local noon, are reconstructed for selected sites in Poland to find if heliotherapy would be an alternative to standard treatment of psoriasis by tube irradiation in medical cabinets. Mountain-resort in the southern Poland, Zakopane, and rural-site in Central Poland, Belsk, are among the best location of potential heliotherapy centers in Poland for late spring/summer season. Łeba, resort on the Baltic Sea coast, is a potential heliotherapy center in June and July. The methodology to disclose possible heliotherapy periods over the territory of Poland could be extended to any region. It would help to prepare an optimal schedule of antipsoriatic heliotherapy that accounts for local weather conditions and medical standards of using UV cabinets.

Variations in solar UVB doses and serum 25-hydroxyvitamin D concentrations may explain the worldwide variation in hip fracture incidence

Variations in solar UVB doses and serum 25-hydroxyvitamin D concentrations may explain the worldwide variation in hip fracture incidence

Re: Vitamin D deficiency among northern Native Peoples

The recent paper by Frost regarding vitamin D deficiency among northern Native Peoples suggested that they do not need as much vitamin D as European-descended populations (1). I respectfully disagree with this contention. I agree that dark-skinned people have been found to have a different calcium economy than pale-skinned people. However, in terms of non-skeletal benefits of vitamin D, there does not seem to be any difference in requirements. It was previously noted that an important reason Alaska Natives had cancer incidence rates 2.5 times higher than American Indians in New Mexico (2) was lower serum 25-hydroxyvitamin D [25(OH)D] concentrations due to differences in solar UVB doses and a change in the diet of Alaska Natives away from ocean fish (3). The comparison was only partly affected by the fact that smoking prevalence is higher in Alaska (2) since rates were also higher for cancers little affected by smoking. There is also very good evidence that African-Americans have poorer health outcomes than White-Americans due to the fact that their mean serum 25(OH)D concentrations are 16 ng/ml vs. 26 ng/ml for White Americans (4). (Published: 24 April 2012) Citation: Int J Circumpolar Health 2012, 71 : 18434 - http://dx.doi.org/10.3402/ijch.v71i0.18434 This Letter has been replied to by Peter Frost. Please follow this link http://www.circumpolarhealthjournal.net/index.php/ijch/article/view/18435 to read his commentary.

Vitamin D and Racial Disparities for Pancreatic Cancer - Letter

The recent article on racial disparities in pancreatic cancer incidence found that black Americans had an unexplained 42% increased risk of pancreatic cancer mortality rates than white Americans, and neither differences in smoking or obesity rates explained this disparity (1). Overlooked in this article was any discussion of the role that vitamin D could play in reducing the risk of pancreatic cancer. Several ecological studies have found that indices of solar UVB doses as proxies for vitamin D production are inversely correlated with pancreatic cancer mortality rates even after accounting for smoking (2). A cohort study also found that pancreatic cancer incidence was significantly inversely correlated with vitamin D intake: compared with participants in the lowest category of total vitamin D intake ( 65.5 versus <32.0 nmol/L; odds ratio, 2.92; 95% confidence interval, 1.56-5.48; P trend = 0.001; ref. 4). The difference between these two studies may well be that one was based on smokers, the other primarily on nonsmokers, and that vitamin D has different effects on pancreatic cancer risk depending on smoking status. There is also the possibility that some of the difference between the studies is how vitamin D intake or status is determined. Ecological studies such as those in the studies by Grant et al. (2, 5) use summertime solar UVB determined from satellite measurements. Casual solar UVB irradiance in summertime can produce 1,000 to 1,500 IU/d, which is sufficient to increase serum 25(OH)D levels by 25 to 37 nmol/L. This amount is higher than the oral intakes in the study by Skinner et al. (3) but similar to the differences noted by Stolzenberg-Solomon et al. (4). Ecological studies have larger populations than observational studies and include both smokers and nonsmokers; the effect of smoking on risk is included through use of an index for smoking such as lung cancer mortality rates. Black Americans have serum 25-hydroxyvitamin D levels ∼10 ng/mL lower than white Americans due to darker skin pigmentation (5). Despite lower vitamin D production from solar UVB for black Americans, solar UVB doses in July have been found inversely correlated with several types of cancer with higher mortality rates for black Americans (breast, colon, rectal, and all cancer; ref. 5). The 10-ng/mL racial difference in serum 25-hydroxyvitamin D levels would explain some of the racial disparity in pancreatic cancer mortality rates, although other factors such as disparities in socioeconomic status, smoking status, and medical treatment may also play a role. Further studies are required to properly apportion the attribution to each factor. Disclosure of Potential Conflicts of Interest W.B. Grant received funding from the UV Foundation (McLean, VA), the Vitamin D Society (Canada), the Sunlight Research Forum (Veldhoven), and Bio-Tech-Pharmacal (Fayetteville, AR). The author received funding from the UV Foundation (McLean, VA), the Sunlight Research Forum (Veldhoven), and Bio-Tech-Pharmacal (Fayetteville, AR) and have previously received funding from the Vitamin D Society (Canada).

The effect of solar UVB doses and vitamin D production, skin cancer action spectra, and smoking in explaining links between skin cancers and solid tumours

The report of differences between skin cancer rates and solid tumours in sunny versus less sunny countries [Tuohimaa P, Pukkala E, Scelo G, et al. Does solar exposure, as indicated by the non-melanoma skin cancers, protect from solid cancers: Vitamin D as a possible explanation. Eur J Cancer 2007; 43: 1701–12] raised some important questions regarding the roles of solar ultraviolet (UV) irradiance and cancer risk. The findings can likely be explained based on the effects of UVB dose on cancer risk, the action spectra of different skin cancers, the amount of skin exposed, and the differential effects of smoking on cancer risk. Solar UVB has been found inversely correlated with about 20 types of cancer in ecological and cohort studies in sunny countries. Vitamin D and calcium were recently found to greatly reduce cancer incidence in a prospective double-blind study. Epidemiological studies suggest that the action spectra for skin cancers vary, with solar UVB most important for squamous cell carcinoma, UVA most important for melanoma, and both important for basal cell carcinoma. These differences may explain the different standardised incidence ratios for solid tumours with respect to the different skin cancers in sunny countries. Smoking has been reported as a risk factor for non-melanoma skin cancers, but has been found inversely correlated with melanoma, which may explain some of the differences in standardised incidence ratios for solid tumours linked to smoking with respect to type of skin cancer. In Nordic countries, less skin is generally exposed (in head and neck regions, the most frequent sites of squamous cell carcinoma) resulting in reduced vitamin D production.

Elevated UV-B radiation reduces genome stability in plants.

Long-term depletion of the stratospheric ozone layer contributes to an increase in terrestrial solar ultraviolet-B radiation. This has deleterious effects on living organisms, such as DNA damage. When exposed to elevated ultraviolet-B radiation (UV-B; 280-315 nm), plants display a wide variety of physiological and morphological responses characterized as acclimation and adaptation. Here we show, using special sun simulators, that elevated solar UV-B doses increase the frequency of somatic homologous DNA rearrangements in Arabidopsis and tobacco plants. Increases in recombination are accompanied by a strong induction of photolyase and Rad51 gene expression. These genes are putatively involved in major DNA repair pathways, photoreactivation and recombination repair. In mutant Arabidopsis plants that are deficient in photoreactivating ultraviolet-induced cyclobutane pyrimidine dimers, recombination under elevated UV-B regimes greatly exceeds wild-type levels. Our results show that homologous recombination repair pathways might be involved in eliminating UV-B-induced DNA lesions in plants. Thus, increases in terrestrial solar UV-B radiation as forecasted for the early 21st century may affect genome stability in plants.