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

Nonlinear relationship between serum 25-hydroxyvitamin D and lipid profile in Chinese adults

Background

Previous studies on the liner associations between serum 25-hydroxyvitamin D [25(OH)D] levels and lipid profiles revealed ambiguous findings. The current study therefore tried to elucidate the possible non-linear associations between 25(OH)D and lipid profiles.

Methods

This study involved 8,516 adult participants (aged 18-74 years, males N = 3,750, females N = 4,766) recruited from the Dalian health management cohort (DHMC). The risk (OR) for specific dyslipidemias was estimated across the serum 25(OH)D levels and the cut-off value for serum 25(OH)D were determined by using logistic regression, restricted cubic spline, and piecewise linear regression methods, adjusted for age, sex, season, and ultraviolet index.

Results

In this study, a high prevalence of 25(OH)D deficiency was observed in the participants (65.05%). The level of 25(OH)D showed the inverse U-shaped correlations with the risks (ORs) of abnormal lipid profile, with inflection points observed at 23.7 ng/ml for hypercholesterolemia, 24.3 ng/ml for hypertriglyceridemia, 18.5 ng/ml for hyper-low-density lipoprotein cholesterolemia, 23.3 ng/ml for hypo-high-density lipoprotein cholesterolemia, 23.3 ng/ml for hyper-non-high-density lipoprotein cholesterol, and 24.3 ng/ml for high remnant cholesterol. The stratified analyses showed that the risk for most dyslipidemias related to deficiency of 25(OH)D was particularly increased among females aged 50-74 (except for hypertriglyceridemia, where the highest risk was among men aged 50-74 years), during winter/spring or under low/middle ultraviolet index environments.

Conclusions

Nonlinear inverse U-shaped associations were observed between 25(OH)D levels and abnormal lipid profile. The risk was particularly increased among females aged 50-74, during winter/spring period or under lower ultraviolet index environments. In vitamin D deficient subjects [25(OH)D <20 ng/ml], a positive association of serum vitamin D levels with the risk for dyslipidemia was observed, which needs a further.

Ambient ultraviolet-B radiation, supplements and other factors interact to impact vitamin D status differently depending on ethnicity: A cross-sectional study

BACKGROUND & AIMS

Many determinants of vitamin D status have been well-described, yet supplementation guidelines largely follow a one-size-for-all model and deficiency remains common. We hypothesised that accounting accurately for ultraviolet-B (UVB) radiation and considering interactions could advance understanding of vitamin D status.

METHODS

Asian, Black, and White participants from the UK Biobank cohort were included (N = 438,978). The Tropospheric Emission Monitoring Internet Service provided UVB data which we linked to participants' place of residence. UVB dose over 135 days prior to blood draw was weighted and added, yielding cumulative and weighted UVB (CW-D-UVB). The association between 25(OH)D and selected variables was assessed in multivariable linear regression models with and without interactions, stratified by ethnicity. Predictors were ranked using standardised β-coefficients.

RESULTS

Median 25(OH)D differed by ethnicity (Asian: 25.4 nmol/L (10.2 ng/mL), Black: 30.6 nmol/L (12.2 ng/mL), White: 47.9 nmol/L (19.2 ng/mL), p-value < 0.001). CW-D-UVB was strongly associated with 25(OH)D in all ethnicities. It was the most important predictor in White (βAsian = 0.15, βBlack = 0.20, βWhite = 0.35), whereas supplementation was in Asian and Black participants (βAsian = 0.30, βBlack = 0.24, βWhite = 0.21). We identified statistically significant interactions between BMI:supplementation (all), CW-D-UVB:sex (Asian and White), and CW-D-UVB:age (Black and White), and in White population between CW-D-UVB and supplementation, BMI, and cholesterol.

CONCLUSION

Vitamin D deficiency was widespread, particularly among non-White individuals. UVB was a strong predictor of 25(OH)D and the effect was modified by other factors. Findings suggest that accurately measured ambient-UVB radiation and interactions could improve 25(OH)D prediction models, and support personalised approaches to vitamin D optimisation.

Intense Testing and Use of Vitamin D Supplements Leads to Slow Improvement in Vitamin D Adequacy Rates: A Cross-Sectional Analysis of Real-World Data

BACKGROUND

Vitamin D testing (VDT) and supplement use (VDS) are on the rise, but most patients remain deficient (<30 ng/mL-VDD). We designed the present real-world study to assess this paradox.

METHODS

We reviewed data from all patients visiting our clinics between 2014 and 2022. We estimated the rate of patients with vitamin D adequacy (≥30 ng/mL) (VDA) by year and month of testing, the dose of VDS (low (≤1200 IU/day), medium (1201-3000 I/day) and high dose (>3000 IU/day)), intake duration (short-term (<12 months) and long-term use (≥12 months)), and timing of use (current use, former use, no use).

RESULTS

We enrolled n = 6912 subjects with vitamin D measurements: n = 5195 females (75.2%), age 44.0 ± 16.8 years, BMI 27.9 ± 6.5 kg/m2; never users: n = 5553 (80.3%), former users: n = 533 (7.7%), current users: n = 826 (12.0%). Current use of VDS was higher in females. VDT rose from 42.1% in 2014 to 92.7% in 2022, and VDA rose from 14.8% to 25.5% for the same time. VDA was found overall in n = 1511 (21.9%); Never users: n = 864 (15.6%), Former users: n = 123 (23.2%); and Current users: n = 370 (44.8%). The maximal VDA (67.9%) was found in subjects using high-dose VDS in the long term.

CONCLUSIONS

Despite the significant rise in VDT and VDS use, VDA was found in a minority of patients. Prolonged use of high-dose supplements produces modest improvements in VDA.

Moving towards more sustainable diets: Is there potential for a personalised approach in practice?

Discourse on the relationship between food production, healthy eating and sustainability has become increasingly prominent and controversial in recent years. Research groups often take one perspective when reporting on sustainable diets, and several often neglect considerations for the multiple aspects that make a diet truly sustainable, such as cultural acceptability, differences in nutritional requirements amongst the population and the efficiency of long-term dietary change. Plant-based diets are associated with lower greenhouse gas emissions (GHGEs) and have been linked with better health outcomes, including lower risk of diet-related chronic disease. However, foods associated with higher GHGE, such as lean red meat, fish and dairy, have beneficial nutritional profiles and contribute significantly to micronutrient intakes. Some research has shown that diets associated with lower GHGE can be less nutritionally adequate. Several countries now include sustainability recommendations in dietary guidelines but use vague language such as "increase" or "consume regularly" when referring to plant-based foods. General population-based nutrition advice has poor adherence and does not consider differences in nutritional needs. Although modelling studies show potential to significantly reduce environmental impact with dietary changes, personalising such dietary recommendations has not been studied. Adapting recommendations to the individual through reproducible methods of personalised nutrition has been shown to lead to more favourable and longer-lasting dietary changes compared to population-based nutrition advice. When considering sustainable healthy dietary guidelines, personalised feedback may increase the acceptability, effectiveness and nutritional adequacy of the diet. A personalised approach has the potential for delivering a new structure of more sustainable healthy food-based dietary guidelines. This review evaluates the potential to develop personalised sustainable healthy food-based dietary guidelines and discusses potential implications for policy and practice.

Influence of Strict Lockdown on Vitamin D Deficiency in Pregnant Women: A Word of Caution

The main source of vitamin D results from skin sunlight exposure. Vitamin D deficiency (VDD) is linked to several adverse events during pregnancy. While performing a cross-sectional study with 886 pregnant women in Elda (Spain) from September 2019 to July 2020 to determine the association of VDD with gestational diabetes mellitus in relation to body mass index, a strict lockdown (SL) due to the COVID-19 pandemic was declared from 15 March 2020 to 15 May 2020. To determine if VDD prevalence in the local population of pregnant women was influenced by SL, a retrospective cross-sectional study was conducted to estimate the prevalence odds ratio (POR) for the association of VDD and SL. A crude logistic regression model was calculated, and then further adjusted by the biweekly measured vitamin D-specific UVB dose in our geographical area. The POR during SL was 4.0 (95%CI = 2.7-5.7), with a VDD prevalence of 77.8% in the quarantine period. Our results revealed that VDD prevalence in pregnant women was influenced by SL. This valuable information could guide us in future if public officials order the population to stay indoors for any given reason.