Changes in the total ozone content over the period 2006 to 2100 and the effects on the erythemal and vitamin D effective UV doses for South America and Antarctica

Projected changes in ultraviolet index and UV doses over the twenty-first century: impacts of ozone and aerosols from CMIP6

This study evaluated the health-related weighted ultraviolet radiation (UVR) due to the total ozone content (TOC) and the aerosol optical depth (AOD) changes. Clear-sky Ultraviolet Index (UVI), daily doses, and exposure times for erythema induction (Dery and Tery) and vitamin D synthesis (DvitD and TvitD) were computed by a radiative transfer estimator. TOC and AOD data were provided by six Earth System Models (ESMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6). For projections, we consider four Shared Socioeconomic Pathways scenarios-SSPs (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5)-and two time-slices (near: 2041-2060 and far future: 2081-2100). UVR projections showed pronounced changes for the summer hemispheres in the far future. TOC increases in mid- and high latitudes of the Southern Hemisphere caused decreases in UVR at the summer solstice. However, projections did not indicate sun-safe exposure conditions in South America, Australia, and Southern Africa. On the contrary, exposure around solar noon from 10 to 20 min will still be sufficient to induce erythema in skin type III individuals throughout this century. In southern Argentina and Chile, the UVR insufficiency for vitamin D synthesis at solar noon in skin type III remains the same during this century at the winter solstice. In the Northern Hemisphere, UVI and Dery at the summer solstice should remain high (UVI ≥ 8; Dery ~ 7.0 kJ m-2) in highly populated locations. Above 45 °N, UVR levels cannot be enough to synthesize vitamin D in skin type III during the boreal winter. Our results show that climate change will affect human health through excess or lack of solar UVR availability.

Identifying gaps on health impacts, exposures, and vulnerabilities to climate change on human health and wellbeing in South America: a scoping review

There is an important gap in regional information on climate change and health, limiting the development of science-based climate policies in South American countries. This study aims to identify the main gaps in the existing scientific literature on the impacts, exposure, and vulnerabilities of climate change on population health. A scoping review was performed guided by four sub-questions focused on the impacts of climate change on physical and mental health, exposure and vulnerability factors of population to climate hazards. The main findings showed that physical impacts mainly included infectious diseases, while mental health impacts included trauma, depression, and anxiety. Evidence on population exposure to climate hazards is limited, and social determinants of health and individual factors were identified as vulnerability factors. Overall, evidence on the intersection between climate change and health is limited in South America and has been generated in silos, with limited transdisciplinary research. More formal and systematic information should be generated to inform public policy.

Funding

None.

Vitamin D Determinants, Status, and Antioxidant/Anti-inflammatory-Related Effects in Cardiovascular Risk and Disease: Not the Last Word in the Controversy

Beyond its key role in calcium homeostasis, vitamin D has been found to significantly affect the cardiovascular (CV) system. In fact, low vitamin D levels have been associated with increased CV risk, as well as increased CV morbidity and mortality. The majority of effects of this molecule are related directly or indirectly to its antioxidative and anti-inflammatory properties. Generally, vitamin D insufficiency is considered for 25-hydroxyvitamin D (25(OH)D) levels between 21-29 ng/mL (corresponding to 52.5-72.5 nmol/L), deficiency as 25(OH)D levels less than 20 ng/mL (<50 nmol/L), and extreme deficiency as 25(OH)D less than 10 ng/mL (<25 nmol/L). However, the definition of an optimal vitamin D status, as defined by 25(OH)D, remains controversial for many extra-bone conditions, including CV disease. In this review, confounding factors affecting the 25(OH)D measurement and status will be discussed. In particular, available evidence on the mechanism and role of vitamin D in relation to CV risk and disease through its antioxidant effect will be reported, also facing the aspect regarding the debate on the minimum blood 25(OH)D level required to ensure optimal CV health.

Correlation between meteorological factors and vitamin D status under different season

Pregnant women with low vitamin D levels tend to have poor clinical outcomes. Meteorological factors were associated with vitamin D. Here, we aimed to study the current status of 25-Hydroxy vitamin D (25(OH)D) concentrations in pregnant women in Kunshan city and investigate the meteorological factors associated with 25(OH)D levels under different seasons. The correlation between meteorological factors and 25(OH)D levels was estimated by cross-correlation analysis and multivariate logistic regression. A restrictive cubic spline method was used to estimate the non-linear relationship. From 2015 to 2020, a total of 22,090 pregnant women were enrolled in this study. Pregnant women with 25(OH)D concentrations below 50 nmol/l represent 65.85% of the total study population. There is a positive correlation between temperature and 25(OH)D. And there is a protective effect of the higher temperature on vitamin D deficiency. However, in the subgroup analysis, we found that in autumn, high temperatures above 30 °C may lead to a decrease in 25(OH)D levels. This study shows that vitamin D deficiency in pregnant women may widespread in eastern China. There is a potential inverted U-shaped relationship between temperature and 25(OH)D levels, which has implications for understanding of vitamin D changes under different seasons.

The Effect of Sunlight Exposure on Vitamin D Status in Countries of Low and High Latitudes: A Systematic Literature Review

PURPOSE OF THE REVIEW

To conduct a systematic review of studies to investigate the association between climate and vitamin D in humans.

RECENT FINDINGS

There is growing interest in the association between the environment and vitamin D, but robust methods to understand this relationship are lacking. Studies focus mainly on seasonality and latitude. Research quantifying sunlight exposure necessary for adequate vitamin D synthesis in people with darker skin color and those people living at low latitudes are scarce, as are studies in urban populations that may have limited opportunity for sunlight exposure. There are gaps regarding values and timing of exposure to UV radiation required for adequate vitamin D synthesis considering skin color, geography, climate, and local irradiation. Nature-based solutions (NbS) that can mitigate climate change will become increasingly important for preventing hypovitaminosis D. For example, tree-shaded spaces might encourage more participation in outside activities and thereby favor vitamin D synthesis by the skin.

Comprehensive Analysis of Seasonal and Geographical Variation in UVB Radiation Relevant for Vitamin D Production in Europe

Dermal synthesis, following sun exposure, is the main source of vitamin D. This study characterizes ambient UVB radiation relevant for vitamin D production in Europe. A biological weighing function was applied to data from the Tropospheric Emissions Monitoring Internet Service (TEMIS) for 46 capital cities over an 18-year period (2004-2021) to isolate wavelengths relevant for vitamin D production (D-UVB). Cumulative and weighted D-UVB (CW-D-UVB) were calculated to approximate seasonal vitamin D accumulation and diminution. Monthly 25(OH)D concentration measurements were extracted from published reports. All data were analyzed by location and time. Despite a moderate latitudinal range (35-64° N), we observed large-up to five-fold-regional differences: the highest mean diurnal D-UVB dose of 5.57 kJ/m² (SD = 3.55 kJ/m²) was observed in Nicosia (Cyprus) and the lowest in Reykjavik (Iceland, 1.16 ± 1.29 kJ/m²). Seasonal differences in diurnal D-UVB dose were even more pronounced, with a median 36-fold difference between annual peak and trough depending on a location (range: 10- to 525-fold). The mean duration of "vitamin D winter" was 126 days but varied widely (4 to 215 days). Monthly CW-D-UVB and 25(OH)D changes were very strongly correlated: the changes in 25(OH)D concentration increased by 12.6 nmol/L for every 100 kJ/m² increment of CW-D-UVB in population-based studies (r² = 0.79, p-value = 1.16 × 10^-37). Understanding the differences in D-UVB radiation can help understand determinants of vitamin D status and guide region- and season-specific safe and effective sunlight exposure recommendations and vitamin D supplementation guidelines.

Trends in Vitamin D Status Around the World

Vitamin D status varies across all continents and countries. Vitamin D status usually is adequate in Latin America and Australia, but in contrast it is very low in the Middle East and some countries in Asia. Trends in vitamin D status, whether it improves or declines over the years, carry important messages. Trends usually are small, but can be predictors and indicators of general health. Vitamin D status has improved in the older population in the United States, and improvement relates to dairy use and vitamin D supplements. To the contrary, vitamin D status has declined in the Inuit population of Canada due to a change from a traditional fish diet to a Western diet. A large improvement was seen in Finland after mandatory fortification of dairy products was introduced. Determinants of decline are less sun exposure, increased use of sunscreen, increase of body mass index (BMI), less physical activity, and poor socioeconomic status. Determinants of increase are food fortification with vitamin D and vitamin D supplements. Food fortification can lead to a population-wide increase in vitamin D status as shown by the Finnish example. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Vitamin D status and supplementation in Antarctica: a systematic review and meta- analysis

Living at high latitudes is associated with vitamin D (VD) deficiency. An ideal setting to study this is the Antarctic continent, which has temporary inhabitants, but the magnitude of the effect of living in Antarctica and the effects of VD supplementation on this population remain unclear. We performed a systematic review and meta-analysis to assess the effect of temporary residence in Antarctica and impact of VD supplementation on VD status of this population. Random‐effects meta‐analyses were performed to assess serum 25-hydroxyvitamin D (25(OH)D) concentration changes after Antarctic residence (13 studies, 294 subjects) and after VD supplementation (5 studies, 213 subjects). Serum 25(OH)D mean difference after temporary residence in Antarctica was -15.0 nmol/L (95%CI: -25.9, -4.2; I²=92%). Subgroup meta-analyses of studies evaluating Antarctic summer and winter stays showed 25(OH)D only decreases when overwintering (winter 25(OH)D change -17.0 nmol/L [95%CI: -24.1, -9.8; I²=83%] vs. summer 25(OH)D change 1.3 nmol/L [95%CI: -14.6, 17.1; I²=86%]). The meta-analysis of VD supplementation studies in Antarctica showed a mean 25(OH)D increase after supplementation of 10.8 nmol/L (95%CI: 3.3, 18.3; I²=88%). In conclusion, VD status significantly worsens after inhabiting Antarctica, particularly when over-wintering. VD supplementation can prevent worsening of VD status and should be considered in this population.