Reduced nitric oxide synthesis in winter: A potential contributing factor to increased cardiovascular risk.

BACKGROUND: Nitric oxide is a key signalling molecule that elicits a range of biological functions to maintain vascular homeostasis. A reduced availability of nitric oxide is implicated in the progression of cardiovascular diseases and increases the risk of pathogenic events. AIMS: To compare the concentration of nitric oxide metabolites in healthy adults between winter and summer months. DESIGN: An observational study of healthy adults (age 32 ± 9 years) living in central Scotland. METHODS: Thirty-four healthy adults (13 females) were monitored for 7 days in summer and winter to record sunlight exposure (ultraviolet-A (UV-A) radiation), diet, and physical activity. At the end of each phase, blood pressure was measured, and samples of blood and saliva collected. The samples were analysed to determine the concentrations of plasma and salivary nitrate and nitrite and serum 25-hydroxyvitamin D (25(OH)D). RESULTS: The participants maintained similar diets in each measurement phase but were exposed to more UV-A radiation (550%) and undertook more moderate-vigorous physical activity (23%) in the summer than in winter. Plasma nitrite (46%) and serum 25(OH)D (59%) were higher and blood pressure was lower in the summer compared to winter months. Plasma nitrite concentration was negatively associated with systolic, diastolic, and mean arterial blood pressure. CONCLUSIONS: Plasma nitrite, an established marker of nitric oxide synthesis, is higher in healthy adults during the summer than in winter. This may be mediated by a greater exposure to UV-A which stimulates the release of nitric oxide metabolites from skin stores. While it is possible that seasonal variation in nitric oxide availability may contribute to an increased blood pressure in the winter months, the overall impact on cardiovascular health remains to be determined.

In-Flight UV-A Exposure of Commercial Airline Pilots.

INTRODUCTION: Understanding UV exposure is essential for the assessment of its contribution to the occupational risk of pilots developing ocular and skin pathologies. The objective of this observational study was to measure the UV exposure of pilots flying between the United Kingdom and a range of destinations at three different seasons.METHODS: The in-flight UV exposure of pilots was measured on 322 Monarch Airlines short-haul flights on the Airbus A321-231 and Airbus A320-214 to 31 destinations, mostly in Europe, from 4 UK airports in September 2016-August 2017. The erythema effective and UV-A doses were compared with the ICNIRP guidance and typical recreational weekend exposure of UK office workers.RESULTS: The erythema effective radiant doses did not exceed 0.1 SED. For most of the flights, the UV-A exposure was also low. On 27 single sector flights, UV-A exposure could have exceeded the ICNIRP guidance if eye protection was not used.DISCUSSION: The UV exposure in a cockpit is mostly governed by the presence of direct sunlight and the duration of a flight. The average monthly exposures were low and significantly below weekend recreational exposures of UK office workers over a similar period. To assess the contribution of occupational UV exposure to the risk of developing sun-related ocular and cutaneous pathologies, it is important to consider the accumulative flight time, destinations, and UV attenuation of aircraft windshields. Additionally, leisure and recreational outdoor time needs to be considered before meaningful overall risk analysis can be undertaken.Baczynska KA, Brown S, Chorley AC, O'Hagan JB, Khazova M, Lyachev A, Wittlich M. In-flight UV-A exposure of commercial airline pilots. Aerosp Med Hum Perform. 2020; 91(6):501-510.

Method for Measurements of Terrestrial Ultraviolet Radiation on Inclined Surfaces in Personal Dosimetry Field Studies.

Understanding personal ultraviolet radiation (UVR) exposure is essential for the evaluation of the health risks and benefits; however, personal dosimetry could be challenging in large-scale or/and long-term population studies. Alternatively, personal exposure could be simulated using three-dimensional models and lifestyle surveys together with data on a body position with respect to the sun. These models require a real-time input on local environmental UVR. The main challenge in using this method is retrieval of the diffuse irradiance as it requires an often-expensive tracking of solar position. In this study, a hypothesis that UVR measured on a vertical plane in the north direction can be used in the UK as a proxy for diffuse radiation was tested against direct measurements and compared with models based on solar tracker data in Chilton, UK, (51.57°N) in June-July 2018. The statistical analysis over 17 days under all weather conditions showed that for 45° and 90° tilted surfaces the proposed method performed as well as the best of the models based on solar tracker data. A proposed system could offer a portable and low-cost alternative to measurements of diffuse radiation by solar tracking radiometers for spatial distribution of terrestrial erythema effective UVR in population field studies.

Estimating Sun Exposure of Children in Day Care Nurseries in South Oxfordshire, UK.

Exposure to ultraviolet radiation and sunburn during childhood and adolescence is linked to increased risks of melanoma and basal cell carcinoma later in life. Infants and toddlers are thought to be unusually vulnerable to UVR because of lower levels of melanin, a thinner stratum corneum and a higher surface area/body mass ratio. The aim of this study was to assess variations in the available erythema effective radiant doses to young children in day care nurseries in South Oxfordshire, UK over 7 years between 2008 and 2014. The data were analyzed in three distinct seasons according to a series of realistic exposure scenarios taking into account nursery routines. The results indicate the time of year when high doses are to be expected and provide strong support for arguments in favor of raising public awareness of sun protection earlier in the year.

Occupational Ocular UV Exposure in Civilian Aircrew.

INTRODUCTION: Ultraviolet radiation (UVR) increases with altitude; however, there are a number of other factors which may influence ocular exposure during flight. The aim of this study was to assess ocular UVR exposure of pilots in airline and off-shore helicopter operations on different aircraft types and to compare with exposure in a typical office environment. METHOD: In-flight data were captured on equipment including a CCD array spectroradiometer on five return sector European airline flights and one transatlantic flight from London Gatwick in addition to four helicopter flights from Aberdeen Dyce airport. Further data were collected in an office environment from three workstations during summer and winter months. RESULTS: A wide variation in ocular UVA dose was found during flights. The main factor influencing exposure was the UVR transmission of the windshield, which fell into two distinct profile types. In an aircraft with good UVA blocking properties, ocular exposure was found to be equivalent to office exposure and did not exceed international guideline limits regardless of external conditions or flight time. Most aircraft assessed had poor UVA blocking windshields which resulted in an ocular exposure to the unprotected eye in excess of international guideline limits (up to between 4.5 to 6.5 times greater during one flight). No significant UVB dose was found. DISCUSSION: Pilots should be warned of the potential high UVA exposure during flight and advised on the use of sunglasses. A windshield labeling system would allow the pilot to tailor their eye protection practices to that particular aircraft.

Effect of altitude on solar UVR and spectral and spatial variations of UV irradiances measured inWagrain, Austria in winter.

Ultraviolet radiation spectral irradiance was measured at different altitudes on horizontal and tilted planes in different azimuth directions on cloudless days in Austria, in March 2010, within the Impact of Climatic and Environmental factors on Personal Ultraviolet Radiation Exposure project framework. The presented results demonstrate variations of the UVB, UVA and biologically effective spectral irradiance measured on inclined and horizontal surfaces with east, west and south azimuth directions of the vertical surface and the angular position of a detector.