Does Incident Solar Ultraviolet Radiation Lower Blood Pressure?

Time spent in outdoor light is associated with increased blood pressure, increased hypertension risk, and decreased hypotension risk

OBJECTIVE

Light exposure is thought to be associated with blood pressure (BP). However, the existing evidence is inconsistent, and the underlying mechanisms remain unclear.

METHODS

This cohort study enrolled over 300,000 participants from the UK Biobank. Information on the time spent in outdoor light during typical summer and winter days was collected using questionnaires. Cases of hypertension and hypotension were identified using the 10th edition of the International Classification of Diseases codes. Cox proportional hazards regression models were employed to estimate the lightBP associations, and restricted cubic splines were utilized to detect potential nonlinear associations. Subgroup analyses were conducted to identify effect modifiers, and causal mediation analyses were performed to explore potential mechanisms.

RESULTS

Using summer light exposure as an illustration, after a median follow-up of 13.4 years, each additional hour of summer light exposure was found to be associated with an increased risk of hypertension (hazard ratio [HR] 1.011, 95 % confidence interval [CI] 1.0061.017, P-nonlinear=0.803) and a decreased risk of hypotension (0.988, 0.9770.998, P-nonlinear=0.109). The lightBP association was found to be stronger in females (P=0.022), those with short sleep durations (P=0.049), and those with a high genetic risk of hypertension (P<0.001). Potential mechanisms included increases in biological age (proportion mediated, 24.1 %, P<0.001), neutrophil count (5.4 %, P<0.001), body mass index (32.0 %, P<0.001), etc. CONCLUSIONS: Our study revealed a positive lightBP association. Potential mechanisms include inflammation, aging, and lifestyle changes. Further epidemiological and experimental investigations are necessary to validate these findings.

Assessing the relative importance of vitamin D deficiency in cardiovascular health

Previous research has suggested a potential link between vitamin D (VD) deficiency and adverse cardiovascular health outcomes, although the findings have been inconsistent. This study investigates the association between VD deficiency and cardiovascular disease (CVD) within the context of established CVD risk factors. We utilized a Random Forest model to predict both CVD and VD deficiency risks, using a dataset of 1,078 observations from a rural Chinese population. Feature importance was evaluated using SHapley Additive exPlanations (SHAP) to discern the impact of various risk factors on the model's output. The results showed that the model for CVD prediction achieved a high accuracy of 87%, demonstrating robust performance across precision, recall, and F1 score metrics. Conversely, the VD deficiency prediction model exhibited suboptimal performance, with an accuracy of 52% and lower precision, recall, and F1 scores. Feature importance analysis indicated that traditional risk factors such as systolic blood pressure, diastolic blood pressure, age, body mass index, and waist-to-hip ratio significantly influenced CVD risk, collectively contributing to 70% of the model's predictive power. Although VD deficiency was associated with an increased risk of CVD, its importance in predicting CVD risk was notably low. Similarly, for VD deficiency prediction, CVD risk factors such as systolic blood pressure, glucose levels, diastolic blood pressure, and body mass index emerged as influential features. However, the overall predictive performance of the VD deficiency prediction model was weak (52%), indicating the absence of VD deficiency-related risk factors. Ablation experiments confirmed the relatively lower importance of VD deficiency in predicting CVD risk. Furthermore, the SHAP partial dependence plot revealed a nonlinear relationship between VD levels and CVD risk. In conclusion, while VD deficiency appears directly or indirectly associated with increased CVD risk, its relative importance within predictive models is considerably lower when compared to other risk factors. These findings suggest that VD deficiency may not warrant primary focus in CVD risk assessment and prevention strategies, however, further research is needed to explore the causal relationship between VD deficiency and CVD risk.

Curcumin-Loaded Liposomes in Gel Protect the Skin of Mice against Oxidative Stress from Photodamage Induced by UV Irradiation

Prolonged exposure to ultraviolet (UV) irradiation can cause oxidative stress in the skin, accompanied by rapid immunosuppressive effects, resulting in a peroxidation reaction throughout the body. Curcumin (Cur), as the bioactive compound of turmeric, is a natural polyphenol with potent antioxidant properties but is often overlooked due to its poor solubility and low bioavailability. In this study, curcumin-loaded liposomes in a sodium alginate gel complex preparation were designed to improve the bioavailability of curcumin and to study its preventive effect on photodamage. Cur-loaded liposomes (Cur-L), Cur-loaded gel (Cur-G) based on an alginate matrix, and curcumin-loaded liposomes in gel (Cur-LG) were prepared, and their antioxidant effects and drug diffusion abilities were evaluated. The antioxidant capacity of Cur, Cur-L, Cur-G, and Cur-LG was also studied in a mouse model of photodamage. Cur had the highest antioxidant activity at about 4 mg/mL. Cur-LG at this concentration showed antioxidant effects during 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) and H2O2 experiments. During the UV light damage test, Cur-LG demonstrated the ability to effectively neutralize free radicals generated as a result of lipid peroxidation in the skin, serum, and liver, thereby enhancing the overall activity of superoxide dismutase (SOD). In conclusion, using Cur-LG may protect against epidermal and cellular abnormalities induced by UV irradiation.

Impact of surface ultraviolet radiation intensity on hospital admissions for ischemic and hemorrhagic stroke: A large-scale database study using distributed lag nonlinear analysis, 2015-2022, in Harbin, China

OBJECTIVES

Our aim is to evaluate the impact of surface ultraviolet radiation intensity on hospital admissions for stroke and to compare the correlation and differences among different subtypes of strokes.

MATERIALS AND METHODS

We collected daily data on surface ultraviolet radiation intensity, temperature, air pollution, and hospital admissions for stroke in Harbin from 2015 to 2022. Using a distributed lag non-linear model, we determined the correlation between daily surface ultraviolet radiation intensity and the stroke admission rate. Relative risks (RR) with 95% confidence intervals (CI) and attributable fractions (AF) with 95% CI were calculated based on stroke subtypes, gender, and age groups.

RESULTS

A total of 132,952 hospitalized stroke cases (including hemorrhagic and ischemic strokes) were included in the study. We assessed the non-linear effects of ultraviolet intensity on hospitalized patients with ischemic and hemorrhagic strokes. Compared to the maximum morbidity benchmark ultraviolet intensity (19.2 × 10^5 for ischemic stroke and 20.25 for hemorrhagic stroke), over the 0-10 day lag period, the RR for extreme low radiation (1st percentile) was 0.86 (95% CI: 0.77, 0.96), and the RR for extreme high radiation (99th percentile) was 0.86 (95% CI: 0.77, 0.96). In summary, -4.842% (95% CI: -7.721%, -2.167%) and -1.668% (95% CI: -3.061%, -0.33%) of ischemic strokes were attributed to extreme low radiation intensity with a lag of 0 to 10 days and extreme high radiation intensity with a lag of 0 to 5 days, respectively. The reduction in stroke hospitalization rates due to low or high ultraviolet intensity was more pronounced in females and younger individuals compared to males and older individuals. None of the mentioned ultraviolet intensity intensities and lag days had a statistically significant impact on hemorrhagic stroke.

CONCLUSIONS

Our study fundamentally suggests that both lower and higher levels of surface ultraviolet radiation intensity in Harbin, China, contribute to a reduced incidence of ischemic stroke, with this effect lasting approximately 10 days. This finding holds significant potential for public health and clinical relevance.

Association of serum 25-hydroxy vitamin D status with cardiometabolic risk factors and total and regional obesity in southern Iran: evidence from the PoCOsteo study

Cardiometabolic risk factors increase the chance of developing cardiovascular disease (CVD) and type 2 diabetes. Most CVD risk factors are influenced by total and regional obesity. A higher risk of developing CVD may be linked to vitamin D deficiency, which is more prevalent in the older population. With the goal of evaluating the association between vitamin D and cardiometabolic risk factors and total and regional obesity in older adults, this research included 25 (OH) vitamin D3 concentrations and biochemical markers associated with cardiometabolic diseases, as well as total and regional adiposity, which was measured by DXA. A total of 1991 older participants in the PoCOsteo study were included. Overall, 38.5% of participants had vitamin D deficiency. After adjusting for confounders, the results of multiple linear and logistic regression suggested an inverse association between vitamin D and body mass index (P = 0.04), waist circumference (P = 0.001), total fat (P = 0.02), android fat (P = 0.001), visceral fat (P < 0.001), subcutaneous fat (P = 0.01), trunk fat (P = 0.006), arm fat (P = 0.03), high systolic blood pressure (P = 0.004), high total cholesterol (P < 0.001), high LDL-cholesterol (P < 0.001), high serum triglycerides (P = 0.001), and high fasting glucose (P < 0.001). Additionally, higher vitamin D concentrations decreased the risk of dyslipidemia by 2%. Our results showed a significant association between serum vitamin D and a number of cardiometabolic risk factors, including total and regional obesity.

Ultraviolet irradiation benefits left ventricular hypertrophy and mitochondrial morphology of cardiomyocytes in hypertensive rats

Insufficient exposure to sunlight increases the risk of cardiovascular diseases. Hypertensive left ventricular (LV) hypertrophy exacerbates the risks of myocardial ischemia, ventricular arrhythmias, sudden cardiac death, and heart failure. This study aimed to determine the effects of ultraviolet (UV) irradiation on LV hypertrophy and mitochondrial morphology. Eighteen 7-week-old Dahl salt-sensitive (Dahl S) rats were categorized into three groups (n = 6 each) and fed sodium chloride (NaCl) diets, as follows: UV-irradiated [UVB+A (+), 8% NaCl], non-UV-irradiated [UV (-), 8% NaCl], and control [UV (-), 0.3% NaCl]. UV irradiation was administered at a low intensity of 100 mJ/cm2 for 6 days per week. Echocardiography and mitochondrial analyses were performed to evaluate LV hypertrophy and cardiomyocytes, and skin tissues were stained with hematoxylin and eosin to assess the pathological abnormalities at 12 weeks of age. LV mass was significantly reduced in the UVB+A (+) and control groups compared to that in the UV (-) group. Mitochondrial structural abnormalities in cardiomyocytes were observed only in the UV (-) group, but not in the UVB+A (+) or control group. Pathological skin abnormalities were not observed in any of the three groups. These findings suggest the potential benefits of UV irradiation in hypertensive models.

Development and evaluation of machine learning models for predicting large-for-gestational-age newborns in women exposed to radiation prior to pregnancy

INTRODUCTION

The correlation between radiation exposure before pregnancy and abnormal birth weight has been previously proven. However, for large-for-gestational-age (LGA) babies in women exposed to radiation before becoming pregnant, there is no prediction model yet.

MATERIAL AND METHODS

The data were collected from the National Free Preconception Health Examination Project in China. A sum of 455 neonates (42 SGA births and 423 non-LGA births) were included. A training set (n = 319) and a test set (n = 136) were created from the dataset at random. To develop prediction models for LGA neonates, conventional logistic regression (LR) method and six machine learning methods were used in this study. Recursive feature elimination approach was performed by choosing 10 features which made a big contribution to the prediction models. And the Shapley Additive Explanation model was applied to interpret the most important characteristics that affected forecast outputs.

RESULTS

The random forest (RF) model had the highest average area under the receiver-operating-characteristic curve (AUC) for predicting LGA in the test set (0.843, 95% confidence interval [CI]: 0.714-0.974). Except for the logistic regression model (AUC: 0.603, 95%CI: 0.440-0.767), other models' AUCs displayed well. Thereinto, the RF algorithm's final prediction model using 10 characteristics achieved an average AUC of 0.821 (95% CI: 0.693-0.949).

CONCLUSION

The prediction model based on machine learning might be a promising tool for the prenatal prediction of LGA births in women with radiation exposure before pregnancy.

Correlation between vitamin D levels and blood pressure in elderly hypertensive patients with osteoporosis

Objectives

The association between vitamin D and blood pressure in elderly patients with hypertension complicated by osteoporosis remains unclear. The objective of this study is to explore whether vitamin D deficiency contributes to elevated blood pressure in elderly individuals with both hypertension and osteoporosis.

Methods

This study represents a single-center retrospective observational investigation carried out at the Zhongshan Hospital Affiliated to Xiamen University. Ambulatory blood pressure, bone density, vitamin D levels, and additional laboratory parameters were collected upon admission. The association between vitamin D and ambulatory blood pressure outcomes was assessed using Spearman correlation tests and partial correlation analyses. The relationship between vitamin D and changes in blood pressure was analyzed through Generalized Additive Models, and threshold analysis was conducted to explore potential thresholds.

Results

139 patients with newly diagnosed osteoporosis were consecutively included (mean age 73 years, 84.9% female). There is a negative correlation between 25-(OH) D3 and 24 h mean systolic blood pressure (mSBP), diurnal mSBP, nocturnal mSBP, maximum SBP, respectively. The results of the generalized additive model analysis show that there is a nonlinear relationship between 25-(OH) D3 and 24 h mSBP, diurnal mSBP, nocturnal mSBP, respectively. After determining the critical point of 25-(OH) D3 as 42 nmol/L, a segmented linear regression model was used to calculate the effect size and 95% confidence interval on both sides of the critical point. When 25-(OH) D3 is ≤42 nmol/L, it significantly negatively correlates with 24 h, diurnal, and nocturnal mean SBP. Conversely, when 25-(OH) D3 exceeds 42 nmol/L, there is no statistically significant association with 24 h, diurnal, or nocturnal mSBP.

Conclusion

There was a significant negative correlation between vitamin D levels and blood pressure levels in elderly patients with hypertension and osteoporosis.

UVR and RPE - The Good, the Bad and the degenerate Macula

Ultraviolet Radiation (UVR) has a well-established causative influence within the aetiology of conditions of the skin and the anterior segment of the eye. However, a grounded assessment of the role of UVR within conditions of the retina has been hampered by a historical lack of quantitative, and spectrally resolved, assessment of how UVR impacts upon the retina in terms congruent with contemporary theories of ageing. In this review, we sought to summarise the key findings of research investigating the connection between UVR exposure in retinal cytopathology while identifying necessary avenues for future research which can deliver a deeper understanding of UVR's place within the retinal risk landscape.

Photo-neuro-immuno-endocrinology: How the ultraviolet radiation regulates the body, brain, and immune system

Ultraviolet radiation (UVR) is primarily recognized for its detrimental effects such as cancerogenesis, skin aging, eye damage, and autoimmune disorders. With exception of ultraviolet B (UVB) requirement in the production of vitamin D3, the positive role of UVR in modulation of homeostasis is underappreciated. Skin exposure to UVR triggers local responses secondary to the induction of chemical, hormonal, immune, and neural signals that are defined by the chromophores and extent of UVR penetration into skin compartments. These responses are not random and are coordinated by the cutaneous neuro-immuno-endocrine system, which counteracts the action of external stressors and accommodates local homeostasis to the changing environment. The UVR induces electrical, chemical, and biological signals to be sent to the brain, endocrine and immune systems, as well as other central organs, which in concert regulate body homeostasis. To achieve its central homeostatic goal, the UVR-induced signals are precisely computed locally with transmission through nerves or humoral signals release into the circulation to activate and/or modulate coordinating central centers or organs. Such modulatory effects will be dependent on UVA and UVB wavelengths. This leads to immunosuppression, the activation of brain and endocrine coordinating centers, and the modification of different organ functions. Therefore, it is imperative to understand the underlying mechanisms of UVR electromagnetic energy penetration deep into the body, with its impact on the brain and internal organs. Photo-neuro-immuno-endocrinology can offer novel therapeutic approaches in addiction and mood disorders; autoimmune, neurodegenerative, and chronic pain-generating disorders; or pathologies involving endocrine, cardiovascular, gastrointestinal, or reproductive systems.

Impact of ultraviolet radiation on cardiovascular and metabolic disorders: The role of nitric oxide and vitamin D

BACKGROUND/PURPOSE

Ultraviolet (UV) radiation has both harmful and beneficial effects on human skin and health. It causes skin damage, aging, and cancer; however, it is also a primary source of vitamin D. Additionally, UV radiation can impact energy metabolism and has protective effects on several cardiovascular and metabolic disorders in mice and humans. However, the mechanisms of UV protection against these diseases have not been clearly identified.

METHODS

This review summarizes the systemic effects of UV radiation on hypertension and several metabolic diseases such as obesity, diabetes, and nonalcoholic fatty liver disease (NAFLD) in mice, and we also consider the mechanisms of action of the related regulators nitric oxide (NO) and vitamin D.

RESULTS

UV exposure can lower blood pressure and prevent the development of cardiovascular diseases and metabolic disorders, such as metabolic syndrome, obesity, and type 2 diabetes, primarily through mechanisms that depend on UV-induced NO. UV radiation may also effectively delay the onset of type 1 diabetes through mechanisms that rely on UV-induced vitamin D. UV-induced NO and vitamin D play roles in preventing and slowing the progression of NAFLD.

CONCLUSION

UV exposure is a promising nonpharmacological intervention for cardiovascular and metabolic disorders. NO and vitamin D may play a crucial role in mediating these effects. However, further investigations are required to elucidate the exact mechanisms and determine the optimal dosage and exposure duration of UV radiation.

The adverse consequences of not using sunscreens

The adverse effects of solar ultraviolet radiation (UVR) on normal skin are well established, especially in those with poorly melanized skin. Clinically, these effects may be classified as acute, such as erythema or chronic such as keratinocyte and melanocyte skin cancers. Apart from skin type genetics, clinical responses to solar UVR are dependent on geophysical (e.g., solar intensity) and behavioural factors. The latter are especially important because they may result in 'solar overload' with unwanted clinical consequences and ever greater burdens to healthcare systems. Correctly used, sunscreens can mitigate the acute and chronic effects of solar UVR exposure. Laboratory studies also show that sunscreens can inhibit the initial molecular and cellular events that are responsible for clinical outcomes. Despite public health campaigns, global trends continue to show increasing incidence of all types of skin cancer. Large-scale epidemiological studies have shown the benefits of sunscreen use in preventing skin cancer, though it is likely that sunscreen use has not been optimal in such studies. It is evident that without substantial changes in sun-seeking behaviour, sunscreen use is a very important part of the defence against the acute and chronic effects of solar exposure. Ideally, sunscreens should be able to provide the level of protection that reduces the risk of skin cancer in susceptible skin types to that observed in heavily melanized skin.

Systematic review on gene-sun exposure interactions in skin cancer

BACKGROUND

The risk of skin cancer is determined by environmental factors like ultraviolet radiation (UVR), personal habits like time spent outdoors and genetic factors. This review aimed to survey existing studies in gene-environment (GxE) interaction on skin cancer risk, and report on GxE effect estimates.

METHODS

We searched Embase, Medline (Ovid) and Web of Science (Core Collection) and included only primary research that reported on GxE on the risk of the three most common types of skin cancer: basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and melanoma. Quality assessment followed the Newcastle-Ottawa Scale. Meta-analysis was not possible because no two studies examined the same interaction. This review was registered on PROSPERO (CRD42021238064).

RESULTS

In total 260 records were identified after exclusion of duplicates. Fifteen studies were included in the final synthesis-12 used candidate gene approach. We found some evidence of GxE interactions with sun exposure, notably, with MC1R, CAT and NOS1 genes in melanoma, HAL and IL23A in BCC and HAL and XRCC1 in SCC.

CONCLUSION

Sun exposure seems to interact with genes involved in pigmentation, oxidative stress and immunosuppression, indicating that excessive UV exposure might exhaust oxidative defence and repair systems differentially, dependent on genetic make-up. Further research is warranted to better understand skin cancer epidemiology and develop sun exposure recommendations. A genome-wide approach is recommended as it might uncover unknown disease pathways dependent on UV radiation.

Periodontal Disease and Other Adverse Health Outcomes Share Risk Factors, including Dietary Factors and Vitamin D Status

For nearly a century, researchers have associated periodontal disease (PD) with risks of other adverse health outcomes such as cardiovascular disease, diabetes mellitus, and respiratory diseases, as well as adverse pregnancy outcomes. Those findings have led to the hypothesis that PD causes those adverse health outcomes either by increasing systemic inflammation or by the action of periodontopathic bacteria. However, experiments largely failed to support that hypothesis. Instead, the association is casual, not causal, and is due to shared underlying modifiable risk factors, including smoking, diet, obesity, low levels of physical activity, and low vitamin D status. Diabetes mellitus is also considered a risk factor for PD, whereas red and processed meat are the most important dietary risk factors for diabetes. Because PD generally develops before other adverse health outcomes, a diagnosis of PD can alert patients that they could reduce the risk of adverse health outcomes with lifestyle changes. In addition, type 2 diabetes mellitus can often be reversed rapidly by adopting an anti-inflammatory, nonhyperinsulinemic diet that emphasizes healthful, whole plant-based foods. This review describes the evidence that proinflammatory and prohyperinsulinemia diets and low vitamin D status are important risk factors for PD and other adverse health outcomes. We also make recommendations regarding dietary patterns, food groups, and serum 25-hydroxyvitamin D concentrations. Oral health professionals should routinely inform patients with PD that they could reduce their risk of severe PD as well as the risks of many other adverse health outcomes by making appropriate lifestyle changes.

Linkages between COVID-19, solar UV radiation, and the Montreal Protocol

There are several connections between coronavirus disease 2019 (COVID-19), solar UV radiation, and the Montreal Protocol. Exposure to ambient solar UV radiation inactivates SARS-CoV-2, the virus responsible for COVID-19. An action spectrum describing the wavelength dependence of the inactivation of SARS-CoV-2 by UV and visible radiation has recently been published. In contrast to action spectra that have been assumed in the past for estimating the effect of UV radiation on SARS-CoV-2, the new action spectrum has a large sensitivity in the UV-A (315-400 nm) range. If this "UV-A tail" is correct, solar UV radiation could be much more efficient in inactivating the virus responsible for COVID-19 than previously thought. Furthermore, the sensitivity of inactivation rates to the total column ozone would be reduced because ozone absorbs only a small amount of UV-A radiation. Using solar simulators, the times for inactivating SARS-CoV-2 have been determined by several groups; however, many measurements are affected by poorly defined experimental setups. The most reliable data suggest that 90% of viral particles embedded in saliva are inactivated within ~ 7 min by solar radiation for a solar zenith angle (SZA) of 16.5° and within ~ 13 min for a SZA of 63.4°. Slightly longer inactivation times were found for aerosolised virus particles. These times can become considerably longer during cloudy conditions or if virus particles are shielded from solar radiation. Many publications have provided evidence of an inverse relationship between ambient solar UV radiation and the incidence or severity of COVID-19, but the reasons for these negative correlations have not been unambiguously identified and could also be explained by confounders, such as ambient temperature, humidity, visible radiation, daylength, temporal changes in risk and disease management, and the proximity of people to other people. Meta-analyses of observational studies indicate inverse associations between serum 25-hydroxy vitamin D (25(OH)D) concentration and the risk of SARS-CoV-2 positivity or severity of COVID-19, although the quality of these studies is largely low. Mendelian randomisation studies have not found statistically significant evidence of a causal effect of 25(OH)D concentration on COVID-19 susceptibility or severity, but a potential link between vitamin D status and disease severity cannot be excluded as some randomised trials suggest that vitamin D supplementation is beneficial for people admitted to a hospital. Several studies indicate significant positive associations between air pollution and COVID-19 incidence and fatality rates. Conversely, well-established cohort studies indicate no association between long-term exposure to air pollution and infection with SARS-CoV-2. By limiting increases in UV radiation, the Montreal Protocol has also suppressed the inactivation rates of pathogens exposed to UV radiation. However, there is insufficient evidence to conclude that the expected larger inactivation rates without the Montreal Protocol would have had tangible consequences on the progress of the COVID-19 pandemic.

Stratospheric ozone, UV radiation, and climate interactions

This assessment provides a comprehensive update of the effects of changes in stratospheric ozone and other factors (aerosols, surface reflectivity, solar activity, and climate) on the intensity of ultraviolet (UV) radiation at the Earth's surface. The assessment is performed in the context of the Montreal Protocol on Substances that Deplete the Ozone Layer and its Amendments and Adjustments. Changes in UV radiation at low- and mid-latitudes (0-60°) during the last 25 years have generally been small (e.g., typically less than 4% per decade, increasing at some sites and decreasing at others) and were mostly driven by changes in cloud cover and atmospheric aerosol content, caused partly by climate change and partly by measures to control tropospheric pollution. Without the Montreal Protocol, erythemal (sunburning) UV irradiance at northern and southern latitudes of less than 50° would have increased by 10-20% between 1996 and 2020. For southern latitudes exceeding 50°, the UV Index (UVI) would have surged by between 25% (year-round at the southern tip of South America) and more than 100% (South Pole in spring). Variability of erythemal irradiance in Antarctica was very large during the last four years. In spring 2019, erythemal UV radiation was at the minimum of the historical (1991-2018) range at the South Pole, while near record-high values were observed in spring 2020, which were up to 80% above the historical mean. In the Arctic, some of the highest erythemal irradiances on record were measured in March and April 2020. For example in March 2020, the monthly average UVI over a site in the Canadian Arctic was up to 70% higher than the historical (2005-2019) average, often exceeding this mean by three standard deviations. Under the presumption that all countries will adhere to the Montreal Protocol in the future and that atmospheric aerosol concentrations remain constant, erythemal irradiance at mid-latitudes (30-60°) is projected to decrease between 2015 and 2090 by 2-5% in the north and by 4-6% in the south due to recovering ozone. Changes projected for the tropics are ≤ 3%. However, in industrial regions that are currently affected by air pollution, UV radiation will increase as measures to reduce air pollutants will gradually restore UV radiation intensities to those of a cleaner atmosphere. Since most substances controlled by the Montreal Protocol are also greenhouse gases, the phase-out of these substances may have avoided warming by 0.5-1.0 °C over mid-latitude regions of the continents, and by more than 1.0 °C in the Arctic; however, the uncertainty of these calculations is large. We also assess the effects of changes in stratospheric ozone on climate, focusing on the poleward shift of climate zones, and discuss the role of the small Antarctic ozone hole in 2019 on the devastating "Black Summer" fires in Australia. Additional topics include the assessment of advances in measuring and modeling of UV radiation; methods for determining personal UV exposure; the effect of solar radiation management (stratospheric aerosol injections) on UV radiation relevant for plants; and possible revisions to the vitamin D action spectrum, which describes the wavelength dependence of the synthesis of previtamin D3 in human skin upon exposure to UV radiation.

Seasonal variation in blood pressure control across US health systems

OBJECTIVE

We aimed to characterize seasonal variation in US population-based blood pressure (BP) control and BP-related metrics and evaluate the association between outdoor temperature and BP control variation.

METHODS

We queried electronic health records (EHRs) from 26 health systems, representing 21 states, to summarize BP metrics by quarters of 12-month periods from January 2017 to March 2020. Patients with at least one ambulatory visit during the measurement period and a hypertension diagnosis during the first 6 months or prior to the measurement period were included. Changes in BP control, BP improvement, medication intensification, average SBP reduction after medication intensification across quarters and association with outdoor temperature were analyzed using weighted generalized linear models with repeated measures.

RESULTS

Among 1 818 041 people with hypertension, the majority were more than 65 years of age (52.2%), female (52.1%), white non-Hispanic (69.8%) and had stage 1/2 hypertension (64.8%). Overall, BP control and process metrics were highest in quarters 2 and 3, and lowest in quarters 1 and 4. Quarter 2 had the highest percentage of improved BP (31.95 ± 0.90%) and average SBP reduction after medication intensification (16 ± 0.23 mmHg). Quarter 3 had the highest percentage of BP controlled (62.25 ± 2.55%) and lowest with medication intensification (9.73 ± 0.60%). Results were largely consistent in adjusted models. Average temperature was associated with BP control metrics in unadjusted models, but associations were attenuated following adjustment.

CONCLUSION

In this large, national, EHR-based study, BP control and BP-related process metrics improved during spring/summer months, but outdoor temperature was not associated with performance following adjustment for potential confounders.

The effects of exposure to solar radiation on human health

This assessment by the Environmental Effects Assessment Panel (EEAP) of the Montreal Protocol under the United Nations Environment Programme (UNEP) evaluates the effects of ultraviolet (UV) radiation on human health within the context of the Montreal Protocol and its Amendments. We assess work published since our last comprehensive assessment in 2018. Over the last four years gains have been made in knowledge of the links between sun exposure and health outcomes, mechanisms, and estimates of disease burden, including economic impacts. Of particular note, there is new information about the way in which exposure to UV radiation modulates the immune system, causing both harms and benefits for health. The burden of skin cancer remains high, with many lives lost to melanoma and many more people treated for keratinocyte cancer, but it has been estimated that the Montreal Protocol will prevent 11 million cases of melanoma and 432 million cases of keratinocyte cancer that would otherwise have occurred in the United States in people born between 1890 and 2100. While the incidence of skin cancer continues to rise, rates have stabilised in younger populations in some countries. Mortality has also plateaued, partly due to the use of systemic therapies for advanced disease. However, these therapies are very expensive, contributing to the extremely high economic burden of skin cancer, and emphasising the importance and comparative cost-effectiveness of prevention. Photodermatoses, inflammatory skin conditions induced by exposure to UV radiation, can have a marked detrimental impact on the quality of life of sufferers. More information is emerging about their potential link with commonly used drugs, particularly anti-hypertensives. The eyes are also harmed by over-exposure to UV radiation. The incidence of cataract and pterygium is continuing to rise, and there is now evidence of a link between intraocular melanoma and sun exposure. It has been estimated that the Montreal Protocol will prevent 63 million cases of cataract that would otherwise have occurred in the United States in people born between 1890 and 2100. Despite the clearly established harms, exposure to UV radiation also has benefits for human health. While the best recognised benefit is production of vitamin D, beneficial effects mediated by factors other than vitamin D are emerging. For both sun exposure and vitamin D, there is increasingly convincing evidence of a positive role in diseases related to immune function, including both autoimmune diseases and infection. With its influence on the intensity of UV radiation and global warming, the Montreal Protocol has, and will have, both direct and indirect effects on human health, potentially changing the balance of the risks and benefits of spending time outdoors.

The effect of daily UVA phototherapy for 2 weeks on clinic and 24-h blood pressure in individuals with mild hypertension

Latitude and season determine exposure to ultraviolet radiation and correlate with population blood pressure. Evidence for Vitamin D causing this relationship is inconsistent, and temperature changes are only partly responsible for BP variation. In healthy individuals, a single irradiation with 20 J/cm² UVA mobilises NO from cutaneous stores to the circulation, causes arterial vasodilatation, and elicits a transient fall in BP. We, therefore, tested whether low-dose daily UVA phototherapy might be an effective treatment for mild hypertension. 13 patients with untreated high-normal or stage 1 hypertension (BP 130-159/85-99 mm Hg), confirmed by 24-h ambulatory blood pressure (ABP), were recruited. Using home phototherapy lamps they were either exposed to 5 J/cm² full body UVA (320-410 nm) radiation each day for 14 days, or sham-irradiated with lamps filtered to exclude wavelengths <500 nm. After a washout period of 3 ± 1 week, the alternate irradiation was delivered. 24-h ABP was measured on day 0 before either irradiation sequence and on day 14. Clinic BP was recorded on day 0, and within 90 min of irradiation on day 14. There was no effect on 24-h ABP following UVA irradiation. Clinic BP shortly after irradiation fell with UVA (-8.0 ± 2.9/-3.8 ± 1.1 mm Hg p = 0.034/0.029) but not sham irradiation (1.1 ± 3.0/0.9 ± 1.5 mm Hg). Once daily low-dose UVA does not control mildly elevated BP although it produces a transient fall shortly after irradiation. More frequent exposure to UVA might be effective. Alternatively, UVB, which photo-releases more NO from skin, could be tried.

Spatial distribution differences of 25-hydroxyvitamin D in healthy elderly people under the influence of geographical environmental factors

The main targets of this were to screen the factors that may influence the distribution of 25-hydroxyvitamin D[25(OH)D] reference value in healthy elderly people in China, and further explored the geographical distribution differences of 25(OH)D reference value in China. In this study, we collected the 25(OH)D of 25,470 healthy elderly from 58 cities in China to analyze the correlation between 25(OH)D and 22 geography secondary indexes through spearman regression analysis. Six indexes with significant correlation were extracted, and a ridge regression model was built, and the country's urban healthy elderly'25(OH)D reference value was predicted. By using the disjunctive Kriging method, we obtained the geographical distribution of 25(OH)D reference values for healthy elderly people in China. The reference value of 25(OH)D for healthy elderly in China was significantly correlated with the 6 secondary indexes, namely, latitude (°), annual temperature range (°C), annual sunshine hours (h), annual mean temperature (°C), annual mean relative humidity (%), and annual precipitation (mm). The geographical distribution of 25(OH)D values of healthy elderly in China showed a trend of being higher in South China and lower in North China, and higher in coastal areas and lower in inland areas. This study lays a foundation for further research on the mechanism of different influencing factors on the reference value of 25(OH)D index. A ridge regression model composed of significant influencing factors has been established to provide the basis for formulating reference criteria for the treatment factors of the vitamin D deficiency and prognostic factors of the COVID-19 using 25(OH)D reference value in different regions.

An Exploration of How Solar Radiation Affects the Seasonal Variation of Human Mortality Rates and the Seasonal Variation in Some Other Common Disorders

Many diseases have large seasonal variations in which winter overall mortality rates are about 25% higher than in summer in mid-latitude countries, with cardiovascular diseases and respiratory infections and conditions accounting for most of the variation. Cancers, by contrast, do not usually have pronounced seasonal variations in incidence or mortality rates. This narrative review examines the epidemiological evidence for seasonal variations in blood pressure, cardiovascular disease rates and respiratory viral infections in relation to atmospheric temperature and humidity, and solar UV exposure through vitamin D production and increased blood concentrations of nitric oxide. However, additional mechanisms most likely exist by which solar radiation reduces the risk of seasonally varying diseases. Some studies have been reported with respect to temperature without considering solar UV doses, although studies regarding solar UV doses, such as for respiratory infections, often consider whether temperature can affect the findings. More research is indicated to evaluate the relative effects of temperature and sun exposure on the seasonality of mortality rates for several diseases. Since solar ultraviolet-B (UVB) doses decrease to vanishingly small values at higher latitudes in winter, the use of safe UVB lamps for indoor use in winter may warrant consideration.

A Narrative Review of the Evidence for Variations in Serum 25-Hydroxyvitamin D Concentration Thresholds for Optimal Health

Vitamin D3 has many important health benefits. Unfortunately, these benefits are not widely known among health care personnel and the general public. As a result, most of the world's population has serum 25-hydroxyvitamin D (25(OH)D) concentrations far below optimal values. This narrative review examines the evidence for the major causes of death including cardiovascular disease, hypertension, cancer, type 2 diabetes mellitus, and COVID-19 with regard to sub-optimal 25(OH)D concentrations. Evidence for the beneficial effects comes from a variety of approaches including ecological and observational studies, studies of mechanisms, and Mendelian randomization studies. Although randomized controlled trials (RCTs) are generally considered the strongest form of evidence for pharmaceutical drugs, the study designs and the conduct of RCTs performed for vitamin D have mostly been flawed for the following reasons: they have been based on vitamin D dose rather than on baseline and achieved 25(OH)D concentrations; they have involved participants with 25(OH)D concentrations above the population mean; they have given low vitamin D doses; and they have permitted other sources of vitamin D. Thus, the strongest evidence generally comes from the other types of studies. The general finding is that optimal 25(OH)D concentrations to support health and wellbeing are above 30 ng/mL (75 nmol/L) for cardiovascular disease and all-cause mortality rate, whereas the thresholds for several other outcomes appear to range up to 40 or 50 ng/mL. The most efficient way to achieve these concentrations is through vitamin D supplementation. Although additional studies are warranted, raising serum 25(OH)D concentrations to optimal concentrations will result in a significant reduction in preventable illness and death.

Light-induced nitric oxide release in the skin beyond UVA and blue light: Red & near-infrared wavelengths

Nitric oxide (NO) is omnipresent in the body and synthesized by 3 isoenzymes (nNOS, eNOS and iNOS), all detected in human skin. NO can be stored in a pool of compounds readily converted to NO following skin irradiation by UVR and blue light. This non-enzymatic (without NOS involvement) photolytic reaction mobilizes cutaneous stores of NO derivatives to the bloodstream, lowering blood pressure. However, with the likelihood of skin deleterious effects caused by UVR/blue light, safer wavelengths in the red/near-infrared (NIR) spectrum are becoming potential contenders to release cutaneous NO, possibly via NOS temperature-dependent effects. The use of red/NIR light to mobilize NO stores from the body's largest organ (the skin) is auspicious. This review focuses on UVR, blue, red, and NIR spectra and their capacity to release NO in human skin. PubMed and Google Scholar were used as article databases to find relevant publications related to this particular field.

COVID-19: A Redox Disease-What a Stress Pandemic Can Teach Us About Resilience and What We May Learn from the Reactive Species Interactome About Its Treatment

Significance: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing coronavirus disease 2019 (COVID-19), affects every aspect of human life by challenging bodily, socioeconomic, and political systems at unprecedented levels. As vaccines become available, their distribution, safety, and efficacy against emerging variants remain uncertain, and specific treatments are lacking. Recent Advances: Initially affecting the lungs, COVID-19 is a complex multisystems disease that disturbs the whole-body redox balance and can be long-lasting (Long-COVID). Numerous risk factors have been identified, but the reasons for variations in susceptibility to infection, disease severity, and outcome are poorly understood. The reactive species interactome (RSI) was recently introduced as a framework to conceptualize how cells and whole organisms sense, integrate, and accommodate stress. Critical Issues: We here consider COVID-19 as a redox disease, offering a holistic perspective of its effects on the human body, considering the vulnerability of complex interconnected systems with multiorgan/multilevel interdependencies. Host/viral glycan interactions underpin SARS-CoV-2's extraordinary efficiency in gaining cellular access, crossing the epithelial/endothelial barrier to spread along the vascular/lymphatic endothelium, and evading antiviral/antioxidant defences. An inflammation-driven "oxidative storm" alters the redox landscape, eliciting epithelial, endothelial, mitochondrial, metabolic, and immune dysfunction, and coagulopathy. Concomitantly reduced nitric oxide availability renders the sulfur-based redox circuitry vulnerable to oxidation, with eventual catastrophic failure in redox communication/regulation. Host nutrient limitations are crucial determinants of resilience at the individual and population level. Future Directions: While inflicting considerable damage to health and well-being, COVID-19 may provide the ultimate testing ground to improve the diagnosis and treatment of redox-related stress diseases. "Redox phenotyping" of patients to characterize whole-body RSI status as the disease progresses may inform new therapeutic approaches to regain redox balance, reduce mortality in COVID-19 and other redox diseases, and provide opportunities to tackle Long-COVID. Antioxid. Redox Signal. 35, 1226-1268.

UV induced changes in proteome of rats plasma are reversed by dermally applied cannabidiol

UV radiation is known to induce a multiple changes in the metabolism of skin-building cells, what can affect the functioning not only neighboring cells, but also, following signal transduction releasing into the blood vessels, the entire body. Therefore, the aim of this study was to analyze the proteomic disturbances occurred in plasma of chronically UVA/UVB irradiated rats and define the effect on these changes of skin topically applied cannabidiol (CBD). Obtained results showed significant changes in the expression of numerous anti-inflammatory and signaling proteins including: NFκB inhibitor, 14-3-3 protein, protein kinase C, keratin, and protein S100 after UV irradiation and CBD treatment. Moreover, the effects of UVA and UVB were manifested by increased level of lipid peroxidation products-protein adducts formation. CBD partially prevented all of these changes, but in a various degree depending on the UV radiation type. Moreover, topical treatment with CBD resulted in the penetration of CBD into the blood and, as a consequence, in direct modifications to the plasma protein structure by creating CBD adducts with molecules, such as proline-rich protein 30, transcription factor 19, or N-acetylglucosamine-6-sulfatase, what significantly changed the activity of these proteins. In conclusion, it may be suggested that CBD applied topically may be an effective compound against systemic UV-induced oxidative stress, but its effectiveness requires careful analysis of CBD's effects on other tissues of the living organism.

Prenatal exposure to solar radiation and hypertensive disorders of pregnancy

OBJECTIVE

To examine the association between prenatal exposure to solar radiation and hypertensive disorders of pregnancy (HDP).

DESIGN

A multicentre retrospective study.

SETTING

19 hospitals in the USA.

POPULATION

205 888 women with singleton gestation from the Consortium on Safe Labor (2002-2008).

MAIN OUTCOME MEASURES

Gestational hypertension, pre-eclampsia/eclampsia, and pre-eclampsia superimposed on chronic hypertension.

METHODS

Medical records of the participants were linked to solar radiation obtained from the National Solar Radiation Database. Average daily solar radiation of each woman was estimated over the entire pregnancy period and over three trimesters during pregnancy according to hospital sites. Generalised estimated equation was applied to investigate the relationship between quartiles of average daily solar radiation and HDP. Restricted cubic spline was applied to assess the nonlinear associations.

RESULTS

Higher average solar radiation during the entire pregnancy was associated with reduced risks of HDP. Compared with the 1st quartile of solar radiation during the entire pregnancy, odds ratios (ORs) of the 2nd, 3rd and 4th quartiles were respectively 0.80 (95% CI 0.72-0.90), 0.63 (95% CI 0.55-0.73), 0.65 (95% CI 0.54-0.78) for gestational hypertension; 0.66 (95% CI 0.57-0.76), 0.61 (95% CI 0.51-0.73), 0.77 (95% CI 0.62-0.95) for pre-eclampsia, and 0.44 (95% CI 0.36-0.55), 0.42 (95% CI 0.35-0.49), 0.60 (95% CI 0.46-0.78) for superimposed pre-eclampsia.

CONCLUSION

Exposure to higher daily solar radiation during pregnancy is associated with a decreased risk of HDP. The protective effect was stronger for superimposed pre-eclampsia than for pre-eclampsia or gestational hypertension.

TWEETABLE ABSTRACT

Exposure to higher daily solar radiation during pregnancy is associated with a decreased risk of HDP.

Ultraviolet A radiation and COVID-19 deaths in the USA with replication studies in England and Italy

Background

Understanding factors impacting deaths from COVID‐19 is of the highest priority. Seasonal variation in environmental meteorological conditions affects the incidence of many infectious diseases and may also affect COVID‐19. Ultraviolet (UV) A (UVA) radiation induces release of cutaneous photolabile nitric oxide (NO) impacting the cardiovascular system and metabolic syndrome, both COVID‐19 risk factors. NO also inhibits the replication of SARS‐CoV2.

Objectives

To investigate the relationship between ambient UVA radiation and COVID‐19 deaths.

Methods

COVID‐19 deaths at the county level, across the USA, were modelled in a zero‐inflated negative‐binomial model with a random effect for states adjusting for confounding by demographic, socioeconomic and long‐term environmental variables. Only those areas where UVB was too low to induce significant cutaneous vitamin D3 synthesis were modelled. We used satellite‐derived estimates of UVA, UVB and temperature and relative humidity. Replication models were undertaken using comparable data for England and Italy.

Results

The mortality rate ratio (MRR) in the USA falls by 29% [95% confidence interval (CI) 40% to 15%) per 100 kJ m^–2 increase in mean daily UVA. We replicated this in independent studies in Italy and England and estimate a pooled decline in MRR of 32% (95% CI 48% to 12%) per 100 kJ m^–2 across the three studies.

Conclusions

Our analysis suggests that higher ambient UVA exposure is associated with lower COVID‐19‐specific mortality. Further research on the mechanism may indicate novel treatments. Optimized UVA exposure may have population health benefits.

COVID-19 Disease Severity and Death in Relation to Vitamin D Status among SARS-CoV-2-Positive UAE Residents

Insufficient blood levels of the neurohormone vitamin D are associated with increased risk of COVID-19 severity and mortality. Despite the global rollout of vaccinations and promising preliminary results, the focus remains on additional preventive measures to manage COVID-19. Results conflict on vitamin D's plausible role in preventing and treating COVID-19. We examined the relation between vitamin D status and COVID-19 severity and mortality among the multiethnic population of the United Arab Emirates. Our observational study used data for 522 participants who tested positive for SARS-CoV-2 at one of the main hospitals in Abu Dhabi and Dubai. Only 464 of those patients were included for data analysis. Demographic and clinical data were retrospectively analyzed. Serum samples immediately drawn at the first hospital visit were used to measure serum 25-hydroxyvitamin D [25(OH)D] concentrations through automated electrochemiluminescence. Levels < 12 ng/mL were significantly associated with higher risk of severe COVID-19 infection and of death. Age was the only other independent risk factor, whereas comorbidities and smoking did not contribute to the outcomes upon adjustment. Sex of patients was not an important predictor for severity or death. Our study is the first conducted in the UAE to measure 25(OH)D levels in SARS-CoV-2-positive patients and confirm the association of levels < 12 ng/mL with COVID-19 severity and mortality.

Sex and body mass index dependent associations between serum 25-hydroxyvitamin D and pulse pressure in middle-aged and older US adults

High pulse pressure (PP) is a valid indicator of arterial stiffness. Many studies have reported that vitamin D concentration is inversely associated with vascular stiffening. This association may differ depending on sex and body mass index (BMI). This study investigated the associations between vitamin D and PP and evaluated whether these associations differ according to sex and BMI, using data for individuals aged ≥ 50 years from the National Health and Nutrition Examination Survey (NHANES) 2007-2010. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were used as biomarkers of vitamin D levels. High PP was defined as ≥ 60 mmHg. Total 25(OH)D concentrations were dose-dependently associated with lower odds ratios (ORs) for high PP (p-trend = 0.01), after controlling for sociodemographic, behavioral, and dietary factors. When stratified by sex, there was a dose-dependent association between total 25(OH)D concentrations and lower risk of high PP (p-trend < 0.001) in females, but not in males. When stratified by BMI, there was a dose-dependent association between total 25(OH)D concentrations and lower risk of high PP (p-trend < 0.001) in non-overweight subjects, but not in overweight subjects. Improving the vitamin D status could delay elevation of PP and vascular stiffening in female and non-overweight subjects.

Neuropeptides and neurohormones in immune, inflammatory and cellular responses to ultraviolet radiation

Humans are exposed to varying amounts of ultraviolet radiation (UVR) through sunlight. UVR penetrates into human skin leading to release of neuropeptides, neurotransmitters and neuroendocrine hormones. These messengers released from local sensory nerves, keratinocytes, Langerhans cells (LCs), mast cells, melanocytes and endothelial cells (ECs) modulate local and systemic immune responses, mediate inflammation and promote differing cell biologic effects. In this review, we will focus on both animal and human studies that elucidate the roles of calcitonin gene-related peptide (CGRP), substance P (SP), nerve growth factor (NGF), nitric oxide and proopiomelanocortin (POMC) derivatives in mediating immune and inflammatory effects of exposure to UVR as well as other cell biologic effects of UVR exposure.

Temporal patterns of suicide and circulatory system disease-related mortality are inversely correlated in several countries

BACKGROUND

Nearly 800,000 suicides occur worldwide annually and suicide rates are increasing faster than population growth. Unfortunately, the pathophysiology of suicide remains poorly understood, which has hindered suicide prevention efforts. However, mechanistic clues may be found by studying effects of seasonality on suicide and other mortality causes. Suicides tend to peak in spring-summer periods and nadir in fall-winter periods while circulatory system disease-related mortality tends to exhibit the opposite temporal trends. This study aimed to determine for the first time whether monthly temporal cross-correlations exist between suicide and circulatory system disease-related mortality at the population level. If so and if common biological factors moderate risks for both mortality types, such factors may be discoverable and utilized to improve suicide prevention.

METHODS

We conducted time series analyses of monthly mortality data from northern (England and Wales, South Korea, United States) and southern (Australia, Brazil) hemisphere countries during the period 2009-2018 (N = 41.8 million all-cause mortality cases). We used a Poisson regression variant of the standard cosinor model to determine peak months of mortality. We also estimated cross-correlations between monthly mortality counts from suicide and from circulatory system diseases.

RESULTS

Suicide and circulatory disease-related mortality temporal patterns were negatively correlated in Australia (- 0.32), Brazil (- 0.57), South Korea (- 0.32), and in the United States (- 0.66), but no temporal correlation was discernable in England and Wales.

CONCLUSIONS

The negative temporal cross-correlations between these mortality types we found in 4 of 5 countries studied suggest that seasonal factors broadly and inversely moderate risks for circulatory disease-related mortality and suicide, but not in all regions, indicating that the effect is not uniform. Since the seasonal factors of temperature and light exert opposite effects on suicide and circulatory disease-related mortality in several countries, we propose that physiologically-adaptive circulatory system responses to heat and light may increase risk for suicide and should be studied to determine whether they affect suicide risk. For example, heat and light increase production and release of the bioactive gas nitric oxide and reduce circulatory system disease by relaxing blood vessel tone, while elevated nitric oxide levels are associated with suicidal behavior, inverse effects that parallel the inverse temporal mortality patterns we detected.

Sunlight exposure in association with risk of lymphoid malignancy: a meta-analysis of observational studies

PURPOSE

Several observational studies have shown contradictory results regarding the association between sunlight exposure and the risk of malignant lymphoma. Thus, we aimed to systematically determine the association between sunlight exposure and lymphoid malignancy risk through a meta-analysis.

METHODS

A thorough search of four electronic databases (PubMed, Embase, Web of Science, and Scopus) was performed to identify eligible studies until 13 August 2020. A random-effects model was used to calculate risk estimates of sunlight exposure. The main outcome measure was the risk of lymphoid malignancy subtypes with odds ratios (ORs) and 95% confidence intervals (CIs) according to various forms of solar ultraviolet radiation.

RESULTS

In total, 17 case-control studies and 9 cohort studies including 216,285 non-Hodgkin lymphoma (NHL) and 23,017 Hodgkin's lymphoma (HL) patients were included in the final analysis. Personal sunlight exposure was significantly associated with a decreased risk of HL (OR 0.77; 95% CI 0.68-0.87) and NHL (OR 0.81; 95% CI 0.71-0.92), including all subtypes except T-cell lymphoma. Ambient sunlight exposure at residence was associated with a reduced risk of HL (OR 0.88; 95% CI 0.81-0.95) and all NHL subtypes (OR 0.84; 95% CI 0.73-0.96), except for chronic lymphocytic leukemia/small lymphocytic lymphoma. As the number of sunburns and sunbaths increased, the risk of NHL tended to decrease.

CONCLUSION

While there was an observed protective effect both from case-control and prospective studies, substantial heterogeneity was found in the current study. Thus, more evidence is required to confirm that promoting sunlight exposure can prevent the development of lymphoid neoplasia.

Low sun exposure habits is associated with a dose-dependent increased risk of hypertension: a report from the large MISS cohort

In prospective observational cohort studies, increasing sun exposure habits have been associated with reduced risk of cardiovascular mortality. Our aim was to assess possible observational mechanisms for this phenomenon. A written questionnaire was answered by 23,593 women in the year 2000 regarding risk factors for melanoma, including factors of possible interest for hypertension, such as detailed sun exposure habits, hypertension, marital status, education, smoking, alcohol consumption, BMI, exercise, and chronic high stress. Hypertension was measured by the proxy "use of hypertension medication" 2005-2007, and high stress by "need of anti-depressive medication". Sun exposure habits was assessed by the number of `yes' to the following questions; Do you sunbath during summer?, During winter vacation?, Do you travel south to sunbath?, Or do you use sun bed? Women answering 'yes' on one or two questions had moderate and those answering 'yes' on three or four as having greatest sun exposure. The main outcome was the risk of hypertension by sun exposure habits adjusted for confounding. As compared to those women with the greatest sun exposure, women with low and moderate sun exposure were at 41% and 15% higher odds of hypertension (OR 1.41, 95% CI 1.3‒1.6, p < 0.001 and OR 1.15, 95% CI 1.1‒1.2, p < 0.001), respectively. There was a strong age-related increased risk of hypertension. Other risk factors for hypertension were lack of exercise (OR 1.36), a non-fair phenotype (OR 1.08), chronic high stress level (OR 1.8), and lack of university education (OR 1.3). We conclude that in our observational design sun exposure was associated with a dose-dependent reduced risk of hypertension, which might partly explain the fewer deaths of cardiovascular disease with increasing sun exposure.

Physical Determinants of Vitamin D Photosynthesis: A Review

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.

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

This assessment by the Environmental Effects Assessment Panel (EEAP) of the United Nations Environment Programme (UNEP) provides the latest scientific update since our most recent comprehensive assessment (Photochemical and Photobiological Sciences, 2019, 18, 595-828). The interactive effects between the stratospheric ozone layer, solar ultraviolet (UV) radiation, and climate change are presented within the framework of the Montreal Protocol and the United Nations Sustainable Development Goals. We address how these global environmental changes affect the atmosphere and air quality; human health; terrestrial and aquatic ecosystems; biogeochemical cycles; and materials used in outdoor construction, solar energy technologies, and fabrics. In many cases, there is a growing influence from changes in seasonality and extreme events due to climate change. Additionally, we assess the transmission and environmental effects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is responsible for the COVID-19 pandemic, in the context of linkages with solar UV radiation and the Montreal Protocol.

Investigating the Potential for Ultraviolet Light to Modulate Morbidity and Mortality From COVID-19: A Narrative Review and Update

During the COVID-19 (coronavirus disease of 2019) pandemic, researchers have been seeking low-cost and accessible means of providing protection from its harms, particularly for at-risk individuals such as those with cardiovascular disease, diabetes and obesity. One possible way is via safe sun exposure, and/or dietary supplementation with induced beneficial mediators (e.g., vitamin D). In this narrative review, we provide rationale and updated evidence on the potential benefits and harms of sun exposure and ultraviolet (UV) light that may impact COVID-19. We review recent studies that provide new evidence for any benefits (or otherwise) of UV light, sun exposure, and the induced mediators, vitamin D and nitric oxide, and their potential to modulate morbidity and mortality induced by infection with SARS-CoV-2 (severe acute respiratory disease coronavirus-2). We identified substantial interest in this research area, with many commentaries and reviews already published; however, most of these have focused on vitamin D, with less consideration of UV light (or sun exposure) or other mediators such as nitric oxide. Data collected to-date suggest that ambient levels of both UVA and UVB may be beneficial for reducing severity or mortality due to COVID-19, with some inconsistent findings. Currently unresolved are the nature of the associations between blood 25-hydroxyvitamin D and COVID-19 measures, with more prospective data needed that better consider lifestyle factors, such as physical activity and personal sun exposure levels. Another short-coming has been a lack of measurement of sun exposure, and its potential to influence COVID-19 outcomes. We also discuss possible mechanisms by which sun exposure, UV light and induced mediators could affect COVID-19 morbidity and mortality, by focusing on likely effects on viral pathogenesis, immunity and inflammation, and potential cardiometabolic protective mechanisms. Finally, we explore potential issues including the impacts of exposure to high dose UV radiation on COVID-19 and vaccination, and effective and safe doses for vitamin D supplementation.

Insufficient Sun Exposure Has Become a Real Public Health Problem

This article aims to alert the medical community and public health authorities to accumulating evidence on health benefits from sun exposure, which suggests that insufficient sun exposure is a significant public health problem. Studies in the past decade indicate that insufficient sun exposure may be responsible for 340,000 deaths in the United States and 480,000 deaths in Europe per year, and an increased incidence of breast cancer, colorectal cancer, hypertension, cardiovascular disease, metabolic syndrome, multiple sclerosis, Alzheimer's disease, autism, asthma, type 1 diabetes and myopia. Vitamin D has long been considered the principal mediator of beneficial effects of sun exposure. However, oral vitamin D supplementation has not been convincingly shown to prevent the above conditions; thus, serum 25(OH)D as an indicator of vitamin D status may be a proxy for and not a mediator of beneficial effects of sun exposure. New candidate mechanisms include the release of nitric oxide from the skin and direct effects of ultraviolet radiation (UVR) on peripheral blood cells. Collectively, this evidence indicates it would be wise for people living outside the tropics to ensure they expose their skin sufficiently to the sun. To minimize the harms of excessive sun exposure, great care must be taken to avoid sunburn, and sun exposure during high ambient UVR seasons should be obtained incrementally at not more than 5-30 min a day (depending on skin type and UV index), in season-appropriate clothing and with eyes closed or protected by sunglasses that filter UVR.

Does Incident Solar Ultraviolet Radiation Lower Blood Pressure?

Background Hypertension remains a leading global cause for premature death and disease. Most treatment guidelines emphasize the importance of risk factors, but not all are known, modifiable, or easily avoided. Population blood pressure correlates with latitude and is lower in summer than winter. Seasonal variations in sunlight exposure account for these differences, with temperature believed to be the main contributor. Recent research indicates that UV light enhances nitric oxide availability by mobilizing storage forms in the skin, suggesting incident solar UV radiation may lower blood pressure. We tested this hypothesis by exploring the association between environmental UV exposure and systolic blood pressure (SBP) in a large cohort of chronic hemodialysis patients in whom SBP is determined regularly. Methods and Results We studied 342 457 patients (36% black, 64% white) at 2178 US dialysis centers over 3 years. Incident UV radiation and temperature data for each clinic location were retrieved from the National Oceanic and Atmospheric Administration database. Linear mixed effects models with adjustment for ambient temperature, sex/age, body mass index, serum Na+/K+ and other covariates were fitted to each location and combined estimates of associations calculated using the DerSimonian and Laird procedure. Pre-dialysis SBP varied by season and was ≈4 mm Hg higher in black patients. Temperature, UVA and UVB were all linearly and inversely associated with SBP. This relationship remained statistically significant after correcting for temperature. Conclusions In hemodialysis patients, in addition to environmental temperature, incident solar UV radiation is associated with lower SBP. This raises the possibility that insufficient sunlight is a new risk factor for hypertension, perhaps even in the general population.