Impact of vitamin D supplementation on C-reactive protein; a systematic review and meta-analysis of randomized controlled trials

Vitamin D and CRP are associated in hospitalized inflammatory bowel disease (IBD) patients in Shanghai

BACKGROUND AND OBJECTIVES

Patients with inflammatory bowel disease (IBD) are more likely to be confirmed with vitamin D deficiency. However, the association between inflammation and vitamin D remains unclear. The purpose of this study was to evaluate the association between inflammation and vitamin D in hospitalized patients with IBD.

METHODS AND STUDY DESIGN

All the participants were recruited from one teaching hospital from June 2018 to October 2022. Inflammation was evaluated by serum concentration of C-reactive protein (CRP), using an immunoturbidimetric method at admission. We further divided the participants into five groups based on serum CRP levels: <5, 5-9.9, 10-19.9, 20-39.9, and >40mg/L. Serum 25-hydroxy-vitamin D (25-(OH)-D) was assessed by liquid chromatography tandem mass spectrometry. Addi-tional information, including age, sex, body mass index (BMI), IBD (ulcerative colitis vs. Crohn's disease) subtype, was abstracted from medical records.

RESULTS

This study included 1,989 patients with IBD (average age was 39.4 years, 33.8% of them were women, 1,365 CD and 624 UC patients). The median CRP was 5.49 mg/L (range of quartiles: 1.64~19.5 mg/L) and the prevalence of 25-(OH)-D deficiency was 69.8%. CRP was significantly associated with serum level of 25-(OH)-D. The difference in 25-(OH)-D was -4.28 ng/ml (-5.27 ng/ml, -3.31 ng/ml) between two extremist CRP groups after adjustment of potential covariates (age, sex, BMI, type of IBD, dietary type, season, and lymphocyte count). Subgroup analysis in sex, type of IBD, and age, were similar to the main analysis results.

CONCLUSIONS

There was a negative association between CRP levels and vitamin D in hospitalized patients with IBD.

Target Values for 25-Hydroxy and 1,25-Dihydroxy Vitamin D Based on Their Associations with Inflammation and Calcium-Phosphate Metabolism

Target values for 25-hydroxy vitamin D and 1,25(OH)2D or 1,25-dihydroxy vitamin D remain a topic of debate among clinicians. We analysed data collected from December 2012 to April 2020 from two cohorts. Cohort A, comprising 455,062 subjects, was used to investigate the relationship between inflammatory indicators (white blood cell [WBC] count and C-reactive protein [CRP]) and 25(OH)D/1,25(OH)2D. Cohort B, including 47,778 subjects, was used to investigate the connection between 25(OH)D/1,25(OH)2D and mineral metabolism markers (phosphate, calcium, and intact parathyroid hormone [iPTH]). Quadratic models fit best for all tested correlations, revealing U-shaped relationships between inflammatory indicators and 25(OH)D and 1,25(OH)2D. Minimal CRP and WBC counts were observed at 1,25(OH)2D levels of 60 pg/mL and at 25(OH)D levels of 32 ng/mL, as well as of 42 ng/mL, respectively. iPTH correlated inversely with both 1,25(OH)2D and 25(OH)D, while phosphate as well as calcium levels positively correlated with both vitamin D forms. Calcium-phosphate product increased sharply when 25(OH)D was more than 50 ng/mL, indicating a possible risk for vascular calcification. Multiple regression analyses confirmed that these correlations were independent of confounders. This study suggests target values for 25(OH)D between 30-50 ng/mL and for 1,25(OH)2D between 50-70 pg/mL, based particularly on their associations with inflammation but also with mineral metabolism markers. These findings contribute to the ongoing discussion around ideal levels of vitamin D but require support from independent studies with data on clinical endpoints.

Low-grade inflammation from prenatal period to age 6-8 years in a Vitamin D trial

BACKGROUND

Low-grade systemic inflammation measured as high sensitivity C-reactive protein (hs-CRP) has been associated with non-communicable disease risk. We assessed whether prenatal inflammation and early-childhood vitamin D are associated with inflammation until age 6-8.

METHODS

We analyzed blood hs-CRP and 25-hydroxy vitamin D [25(OH)D] in pregnancy, at birth from umbilical cord blood (UCB), from offspring at ages 1, 2, and 6-8 years in the Vitamin D Intervention in Infants (VIDI) study. VIDI was a randomized-controlled trial of vitamin D supplementation of 10 μg/day or 30 μg/day from age 2 weeks until 2 years in 975 infants recruited in 2013-14, with follow-up at age 6-8 in 2019-21 (n = 283).

RESULTS

Pregnancy hs-CRP was associated with UCB hs-CRP (r = 0.18, p < 0.001) but not independently with childhood hs-CRP (Estimate [95% CI] 0.04 [<-0.00, 0.09]). Higher UCB hs-CRP was associated independently with higher hs-CRP until 6-8 years (0.20 [0.12, 0.29]). Infant vitamin D dose had no effect on longitudinal hs-CRP (6-8 years, 0.11 [-0.04, 0.25]). Childhood 25(OH)D were associated positively with hs-CRP until age 6-8 (0.01 [>0.00, 0.01]).

CONCLUSION

Our results indicate that in children, inflammation, assessed by hs-CRP, persists from birth until 6-8 years. We observed positive associations between 25(OH)D and hs-CRP in vitamin D-sufficient children.

IMPACT

High sensitivity C-reactive protein (hs-CRP) concentrations tract from birth to age 8 years Our novel finding suggests a long-lasting pro-inflammatory phenotype in the child Higher vitamin D concentration - but not dose - is associated with higher childhood hs-CRP Chronic disease risk related to inflammation may in part originate from the prenatal period or early childhood Further studies are needed to investigate the effects of inflammation on long-term clinical health outcomes.

The Association of Prenatal C-Reactive Protein and Interleukin-8 Levels with Maternal Characteristics and Preterm Birth

OBJECTIVE

The determinants of preterm birth remain unknown. Excessive maternal inflammation during pregnancy may play an important role in the pathogenesis of preterm birth. Our objective was to describe the association of prenatal levels of proinflammatory C-reactive protein (CRP) and interleukin-8 (IL-8) with preterm birth in participants of the Vitamin D Antenatal Asthma Reduction Trial.

STUDY DESIGN

Five hundred and twenty-eight patients with available samples of both first- and third-trimester plasma were included in this analysis. CRP and IL-8 were measured from maternal prenatal samples. We examined the association between prenatal CRP and IL-8 with maternal health characteristics and the outcome of preterm birth. We also described the patterns of change in CRP and IL-8 from first to third trimester and their association with preterm birth. A subgroup analysis comparing only those with a spontaneous preterm birth phenotype to those with term birth was also performed.

RESULTS

Maternal characteristics including lower educational attainment, higher prepregnancy body mass index, gestational diabetes, lower vitamin D, and an unhealthy diet were associated with elevated levels of prenatal CRP and IL-8. Higher third trimester CRP and an increase in CRP from first to third trimester were associated with an increased odds of preterm birth when compared to lower levels of CRP (adjusted odds ratio [aOR] = 1.49, 95% confidence interval: 1.02, 2.23, p = 0.04) or a decrease in CRP over pregnancy (aOR = 3.06, 95% CI = 1.31,7.55, p = 0.01), after adjusting for potential confounders. These associations were strengthened when comparing only patients with spontaneous preterm birth (n = 22) to those with term births.

CONCLUSION

Higher levels of the proinflammatory markers CRP and IL-8 are associated with indicators of poor maternal health and preterm birth. Prenatal CRP levels may reflect maternal prenatal health status and serve as a predictor of preterm birth, especially among those with spontaneous preterm birth.

KEY POINTS

· Elevated prenatal CRP is associated with poor maternal health.. · High prenatal CRP may predict premature birth, especially spontaneous premature birth phenotypes.. · Vitamin D insufficiency may be a modifiable risk factor for prenatal inflammation..

Pathways and policy options for food and nutrition gaps in arid agricultural farming systems in the Tigray Region, north Ethiopia

Food and nutrition security is a major global challenge especially indeveloping countries.Agriculture is main means of livelihoods and hunger is drastically increasing from time to time especially due to effects of climate change, conflict and other manmade and natural calamities in these countries. Similarly, the Tigray Region is one of the Ethiopia's most food and nutrition insecure regions with agriculture serving as the main source of income and employment. This study was therefore conducted to fill the gap in understanding the socioeconomic situation, bio-physical environment, institutional setting and policy landscape by analysing the existing circumstances in Tigray Region. This research employed quantitative data sets collected from 300 randomely selected Productive Saftey Net Program (PSNP) beneficiarieries and Non-PSNP households using probability proportional to size. The Household Dietary Diversity Score (HDDS) used as a proxy measure to nutrition security as our data is 24 h recall and food gap months as proxy to food security. Besides, Principal Component Analysis (PCA) method is used to construct household asset index. The results of the study revealed that there are clear and significant differences of the PSNP and Non-PSNP households, and gender in land holding (p<0.01%), asset ownership(p<0.01%), food gap months(p<0.01%), dietary diversity(p<0.01%), exposure to hazards and risks, copping strategies, yield, access to agricultural extension services, access to improved varieties (varietal diversification). The male headed households, and Non-PSNP households are better off than the female headed and PSNP households' counterparts. Thus, provision of practical training, conducting farmer's participatory research, field days, promoting and creating access to farmers' preferred high yielding improved varieties and management practices available in the research and extension consortium, support in research and development that develops and disseminate appropriate technologies to help farmers to lower their food gap months is highly important. In addition, sustainable intensification, off-farm employment alternatives, and engaging in agribusiness activities that create resilient livelihood options to those resource poor farm households, strengthening the formal and informal seed system would help to reduce food gap months, improve HDDS, build resilience of the food and nutrition insecure households. Therefore, customized extension services and packages are important for addressing the food and nutrition security gaps by setting goal, outcome and output indicators for future interventions in the research and development arena in filling food gap months, dietary diversity and household asset building through collaboration among relevant stakeholders in the food system.

Modulatory Properties of Vitamin D in Type 2 Diabetic Patients: A Focus on Inflammation and Dyslipidemia

BACKGROUND

Evidence from preclinical studies has found a correlation between the development of type 2 diabetes (T2D) and vitamin D deficiency. However, evidence from randomized controlled trials (RCTs) revealed inconclusive results on vitamin D supplementation. We explored the effect of vitamin D on inflammation and dyslipidemia in T2D.

METHODS

We comprehensively searched for RCTs evaluating the effect of vitamin D in T2D on PubMed. Data were analyzed using Review Manager 5.3 and reports, such as standardized mean difference (SMD) and 95% confidence intervals (CI) at a 5% significant level using a random effect model.

RESULTS

This study revealed a significant reduction in tumor necrosis factor-alpha (TNF-α) SMD = (-0.51, 95%CI (-0.93, -0.09); p = 0.02), high sensitivity C-reactive protein (hs-CRP) SMD = (-1.06, 95%CI (-1.67, -0.45); p < 0.05) in vitamin D compared to placebo. Additionally, interleukin-6 (IL-6) exhibited a marginal effect SMD = (-0.52, 95%CI (-1.05, 0.01), p = 0.05). Furthermore, a significant reduction in the level of triglycerides SMD = (-0.65, 95%CI (-1.11, -0.18), p < 0.05) was observed, concomitant to a significantly increased high-density lipoprotein (HDL) level SMD = (0.53, 95%CI (0.08, 0.98), p = 0.02). However, no statistically significant changes were observed in total cholesterols SMD = (-0.16, 95%CI (-0.57, 0.24), p = 0.43) and low-density lipoprotein (LDL) SMD = (-0.06, 95%CI (-0.37, 0.24), p = 0.67).

CONCLUSIONS

These findings suggest that vitamin D supplementation may be beneficial in ameliorating inflammation and dyslipidemia in T2D patients.

About the associations of vitamin D deficiency and biomarkers of systemic inflammatory response with all-cause and cause-specific mortality in a general population sample of almost 400,000 UK Biobank participants

It is unknown whether the well-known association between vitamin D deficiency and mortality could be explained by the immune system modulating effects of vitamin D, which may protect from a systemic inflammatory response (SIR) to adverse health conditions. This study aims to investigate the interrelationships of vitamin D deficiency, biomarkers of SIR, and mortality. We used multivariate logistic regression with adjustment for 51 covariates to assess the associations of vitamin D deficiency with disadvantageous levels of nine biomarkers of SIR in the UK Biobank cohort. Furthermore, we tested with Cox regression and mediation analysis whether biomarkers of SIR and vitamin D deficiency were independently associated with mortality. We included 397,737 participants aged 37-73 years. Vitamin D deficiency was associated with disadvantageous levels of all blood cell count-based biomarkers, but not with C-reactive protein (CRP)-based biomarkers after adjustment for body weight. Vitamin D deficiency and all biomarkers of SIR were significantly associated with all-cause mortality and mortality from cancer, cardiovascular and respiratory disease. The strength of these associations was unaltered if vitamin D deficiency and biomarkers of SIR were put in the same model. This finding was further supported by the mediation analyses. This study showed that vitamin D deficiency is associated with disadvantageous levels of blood cell count-based but not CRP-based biomarkers of SIR. Vitamin D deficiency and systemic inflammation were independently and strongly associated with mortality. The potential of clinical interventions against both vitamin D deficiency and underlying causes of systemic inflammation should be explored.

Vitamin D status & associations with inflammation in older adults

Research studies have observed associations of vitamin D with inflammation but data in representative older adult studies is lacking. We aimed to investigate the association of C-reactive protein (CRP) with vitamin D status in a representative sample of the older Irish population. The concentrations of 25-hydroxyvitamin D (25(OH)D) and CRP was measured in 5,381 community dwelling Irish adults aged ≥50 years from the Irish Longitudinal Study on Ageing (TILDA). Demographic, health and lifestyle variables were assessed by questionnaire and categorical proportions of CRP were generated by vitamin D status and age. Multi-nominal logistic regression was used to investigate the association of 25(OH)D and CRP status. The prevalence (mean; 95% confidence interval (95% CI)) of normal CRP status (0-5 mg/dL) was 83.9% (82.6-85.0%), elevated status (5-10 mg/dL) 11.0% (9.9-12.0%) and high status (>10 mg/dL) was 5.1% (4.5-5.8%). Mean (95% CI) CRP concentrations were lower in those with normal vs. deficient 25(OH)D status (2.02 mg/dL (1.95-2.08) vs. 2.60 mg/dL (2.41-2.82); p<0.0001). In a logistic regression analysis, those with insufficient or sufficient 25(OH)D status were less likely to have a high CRP status compared to those with deficient 25(OH)D status (insufficient: coefficient (CE) -0.732, 95% CI -1.12-0.33, p<0.0001; sufficient: CE -0.599, 95% CI -0.95-0.24, p = 0.001). In conclusion older adults with deficient vitamin D status had higher levels of inflammation as measured by CRP. Given that inflammation is an important pathological driver of chronic diseases of ageing, and that emerging evidence suggests that vitamin D therapy can reduce inflammation in some disease settings, optimising vitamin D status could represent an effective low risk/low-cost pathway to modulate inflammation in community dwelling older adults.

The Prevalence and Determinants of Vitamin D Status among Older Adults: Data from a Longitudinal Aging Study

Background

Aging is identified as a risk factor for vitamin D deficiency (VDD) therefore this investigation was designed to determine the prevalence of VDD and its determinants in a sample of older adults.

Methods

The data of this study were obtained from the baseline wave of the Longitudinal Aging Study (LAS). Demographic, past medical history, medication history, and smoking behavior were collected using an interview approach. The physical activity and nutritional status of the participants were assessed using a standard questionnaire. Anthropometric indices were measured according to a standard protocol then body mass index (BMI) was calculated. Serum vitamin D and calcium levels were measured by autoanalyzers. Univariate and multiple logistic regression models were applied to detect the associated factors with VDD.

Results

Mean age of the participants was 71.82 (SD = 7.63) years. A total of 1319 people participated in our study, and 51.16% (n = 688) were female. A total of 8.42% (n = 111) of the participants had VDD and 17.06% of them (n = 225) had insufficient vitamin D levels. In the multivariable logistic regression model, the age group of 70-79 years in comparison with the age group of 60-69 years had a 43% less chance of VDD. Furthermore, being overweight (OR = 0.36, P = 0.01) and obese (OR = 0.35, P = 0.02), and taking vitamin D supplements (OR = 0.31, P = 0.04) were significantly associated with VDD.

Conclusions

Our results showed that 25% of older adults had vitamin D deficiency or insufficiency. In addition, some modifiable lifestyle factors were associated with VDD. Given that, old age is considered a risk factor for VDD. Therefore, detection and improvement of VDD may be a preventive measure in at-risk subjects.

Concurrent alteration in inflammatory biomarker gene expression and oxidative stress: how aerobic training and vitamin D improve T2DM

Background

Vitamin D (Vit D) supplementation and Aerobic Training (AT) exert several beneficial effects such as antioxidant and anti-inflammatory actions. The literature on the effects of AT and Vit D supplementation on the oxidative stress biomarkers and gene expression of inflammatory cytokines in patients with Type 2 Diabetes Mellitus (T2DM) is limited. The present study aimed to examine the effects of AT and Vit D supplementation on inflammation and oxidative stress signaling pathways in T2DM patients.

Materials and methods

In this single-blinded, randomized, placebo-controlled trial, 48 men with T2DM (aged 35–50 years with Body Mass Index (BMI) of 25–30 kg/m2) were randomly allocated into four groups: AT+Vit D (n = 10); AT + placebo (AT; n = 10); Vit D (n = 10), and Control + placebo (C; n = 10). The eight-week AT program was executed for 20–40 min/day, at 60–75% of heart rate maximum (HRmax), for 3 days/wks. The Vit D group received 50,000 IU of Vit D supplement capsules per week for 8 weeks. The serum levels of oxidative stress biomarkers and gene expression of inflammatory cytokines in the Peripheral Blood Mononuclear Cells (PBMCs) were evaluated using the RT-PCR method. To analyze the data, paired t-tests and one-way analysis of variance and Tukey’s post hoc test were used at the significance level of P < 0.05.

Results

The result shows that serum 25-OH-Vit D, total nitrite, Total Glutathione (GSH), Total Antioxidant Capacity (TAC), Superoxide Dismutase (SOD), Catalase (CAT), and Glutathione Peroxidase (GPX) increased; and insulin, Fasting Blood Glucose (FBG), Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), High Sensitivity C-Reactive Protein (hs-CRP), Malondialdehyde (MDA), glycated albumin, and Urinary 8-hydroxydeoxyguanine (8-OHdG) decreased significantly in all groups after 8 weeks, except for C. In addition, results of RT-PCR showed that AT+Vit D, Vit D, and AT significantly downregulated the gene expression of Tumor Necrosis Factor-Alpha (TNF-α), Interleukin-1 Beta (IL-1β), Mitogen-Activated Protein Kinases 1 (MAPK1), Nuclear Factor Kappa B (NF-κB) 1 (p50). It also upregulated Interleukin-4 (IL-4) gene expression, Peroxisome Proliferator-Activated Receptor Gamma (PPAR-γ) in T2DM patients compared to the C.

Conclusion

Additionally, the AT+Vit D group showed significantly lower insulin, FBG, HOMA-IR, hs-CRP, MDA, glycated albumin, urinary 8-OHdG, IL-1β, TNF-α, MAPK1, and NF-κB1 (p50) levels and significantly higher serum 25-OH-Vit D, total nitrite, GSH, TAC, CAT, SOD, GPX, IL-4, and PPAR-γ levels compared to the AT and Vit D groups. In T2DM patients, 8 weeks of AT+Vit D had a more significant impact on certain gene expressions related to inflammation and oxidative stress than Vit D or AT alone.

High prevalence, low identification and screening tools of hospital malnutrition in critically- ill patients in Malawi

BACKGROUND/OBJECTIVES

In Africa, approximately two-thirds of patients are at risk of malnutrition on admission and the nutritional status of patients deteriorates during hospitalization, with associated increased morbidity, mortality, and hospital-related cost. This cross-sectional study aimed at estimating rates of malnutrition in critical care units and determining the extent to which malnutrition diagnoses are documented in medical records by physicians, at two public tertiary hospitals in Malawi.

METHODS

A total of 315 adult (n = 112) and paediatric (n = 203) participants from Queen Elizabeth Central Hospital and Kamuzu Central Hospital, were included in the analysis. Nutrition status was measured by Subjective Global Assessment (SGA) and Mid-Upper Arm circumference (MUAC) and medical notes were reviewed, in both adults and paediatrics.

RESULTS

In adults, more than half were malnourished, with a higher proportion considered moderately-to-severely malnourished using SGA compared to MUAC (84.8%; 57.3%, respectively). Likewise, in paediatrics, a higher proportion was considered moderately-to-severely malnourished using SGA compared to MUAC (84.7%; 23.4%, respectively). Both adult and paediatric patients with cancer had the highest rates of malnutrition. Only 12.9% and 9.6% had documentation of malnutrition diagnosis in the medical record, for paediatrics and adult patients, respectively.

CONCLUSION

The high rates of hospital malnutrition in critically ill patients in Malawi call for comprehensive screening practices and methods; complemented by documentation of the malnutrition diagnosis and use of nutrition interventions by dietitians. This includes enteral, parenteral and supplemental nutrition as a prerequisite for patient recovery in hospitals.

Trends and determinants of minimum acceptable diet intake among infant and young children aged 6-23 months in Ethiopia: a multilevel analysis of Ethiopian demographic and health survey

BACKGROUND

The minimum acceptable diet (MAD) has been used globally as one of the main indicators to assess the adequacy of feeding practices. More than half of the causes of under-five child mortality in developing countries including Ethiopia are attributed to malnutrition. With the exception of anecdotal information on the subject, progress overtime and how it influences the MAD has not been studied or well understood. Thus, this study aimed to determine the trends and determinants of MAD intake among infants and young children aged 6-23 months in Ethiopia.

METHODS

A community-based national survey dataset from the Ethiopian demographic and health survey (EDHS) 2019 were to identify predictors of MAD. In addition, the 2011, 2016, and 2019 EDHS data was used for trend analysis. The World Health Organization indicators were used to measure MAD. A weighted sample of 1457 infants and young children aged 6-23 months. A mixed-effects multi-level logistic regression model was employed using STATA version 16.0.

RESULTS

The proportions of infants and young children who received the MADs in Ethiopia were 4.1%, 7.3%, and 11.3% during the survey periods of 2011, 2016, and 2019, respectively. Having mothers who attended primary education [adjusted odds ratio (aOR) =2.33 (95% C.I 1.25 to 4.35)], secondary education [aOR = 2.49 (95% C.I 1.03 to 6.45)], or higher education [aOR = 4.02 (95% C.I 1.53 to 10.54)] compared to those who never attended formal education. Being in a medium househoold wealth [aOR = 4.06 (95% C.I 1.41 to 11.72)], higher-level wealth [aOR = 4.91 (95% C.I 1.49 to 16.13)] compared to those in the lowest househoold wealth. Being in 12-18 months age group [aOR = 2.12 (95% C.I 1.25 to 3.58)] and in 18-23 months age category [aOR = 2.23 (1.29 to 3.82)] compared to 6-11 months age group; and having postnatal check-ups [aOR = 2.16 (95% C.I 1.31 to 3.55)] compared to their counterparts. Moreover, residing in urban [aOR = 3.40 (95% C.I 1.73 to 6.68)]; living in a communities' where majority had a media exposure [aOR 1.80 (95% C.1.17 to 2.77)] were found to be significantly influenc consumption of the MAD.

CONCLUSIONS

The trends of MAD among children of 6-23 months was steady in Ethiopia. Sociodemographic and socioeconomic factors such as maternal education, child age, household wealth; and health system related factors such as maternal postnatal check-ups had a significant influence on infants' and young children's MAD feeding. Indeed, commnity-level factors such as place of residence, and media exposure affect the MAD of infants and young children. Thus, behavioral change communication interventions are recommended to improve dietary practices in infants and young children.

Higher Dietary Inflammatory Index Scores Are Associated With Stress and Anxiety in Dormitory-Residing Female University Students in the United Arab Emirates

Dormitory-residing university students are at-risk of mental health problems related to unhealthy diets. The purpose of this study was to assess the association between dietary inflammatory potential and mental health of dormitory-residing female university students. This cross-sectional study was comprised of 260 undergraduate females residing in dormitories of the largest university in United Arab Emirates during Spring 2019. The Energy-adjusted Dietary Inflammatory Index (E-DIITM) scores calculated from 37 food parameters were derived from two 24-h dietary recalls. The logistic regression analysis was used to estimate odds ratios (ORs) and 95% CIs for the E-DII score in relation to depression, anxiety, and stress. The E-DII scores (mean = 2.98 ± 1.17) were categorized into: tertile 1 (−1.96–2.62), tertile 2 (2.63–3.52), and tertile 3 (3.53–5.60), representing less to more proinflammatory diets. Students in the E-DII tertile 3 had significantly higher depression, anxiety, and stress scores. The logistic regression analysis showed that each point increase in the E-DII score was associated with symptoms of stress (OR = 1.41; 95% CI: 1.12–1.77; p = 0.003) and anxiety (OR = 1.35; 95% CI: 1.07–1.69; p = 0.01). Relative to students in the E-DII tertile 1, those students in the E-DII tertile 3 were more likely to be at higher risk of stress and anxiety ORE−DIItertile3vs1 = 2.89 (1.44–5.79) and 2.88 (1.49–5.56), respectively. Overall, stress and anxiety were associated with proinflammatory diets in dormitory-residing female university students, suggesting the need for targeted interventions to increase the anti-inflammatory capacity of diet and improve mental wellbeing in students on university campuses.

An Overview of Systematic Reviews of the Role of Vitamin D on Inflammation in Patients with Diabetes and the Potentiality of Its Application on Diabetic Patients with COVID-19

Almost two years have passed since the outbreak reported for the first time in Wuhan of coronavirus disease 2019 (COVID-19), due to severe acute respiratory syndrome (SARS)-CoV-2 coronavirus, rapidly evolved into a pandemic. This infectious disease has stressed global health care systems. The mortality rate is higher, particularly in elderly population and in patients with comorbidities such as hypertension, diabetes mellitus, cardiovascular disease, chronic lung disease, chronic renal disease, and malignancy. Among them, subjects with diabetes have a high risk of developing severe form of COVID-19 and show increased mortality. How diabetes contributes to COVID-19 severity remains unclear. It has been hypothesized that it may be correlated with the effects of hyperglycemia on systemic inflammatory responses and immune system dysfunction. Vitamin D (VD) is a modulator of immune-response. Data from literature showed that vitamin D deficiency in COVID-19 patients increases COVID-19 severity, likely because of its negative impact on immune and inflammatory responses. Therefore, the use of vitamin D might play a role in some aspects of the infection, particularly the inflammatory state and the immune system function of patients. Moreover, a piece of evidence highlighted a link among vitamin D deficiency, obesity and diabetes, all factors associated with COVID-19 severity. Given this background, we performed an overview of the systematic reviews to assess the association between vitamin D supplementation and inflammatory markers in patients with diabetes; furthermore, vitamin D’s possible role in COVID-19 patients was assessed as well. Three databases, namely MEDLINE, PubMed Central and the Cochrane Library of Systematic Reviews, were reviewed to retrieve the pertinent data. The aim of this review is to provide insight into the recent advances about the molecular basis of the relationship between vitamin D, immune response, inflammation, diabetes and COVID-19.

Vitamin D deficiency associations with metabolic, bone turnover and adverse general health markers in community free living adults

BACKGROUND

Although there is some evidence that vitamin D deficiency is highly prevalent in the Middle East, however its health impact is still not clear. The aim of this study was to assess the prevalence, causes and health implications of vitamin D deficiency in local United Arab Emirates (UAE) citizens.

METHODS

A cross-sectional study was conducted on community free living adults living in the city of Al Ain, UAE. Following informed written consent eligible subject's blood and urine samples were taken for measurements of vitamin D [25(OH)D], metabolic and bone turnover markers. Clinical assessment that includes general and self-rated health, muscle health, and physical activity were also performed.

RESULTS

A total of 648 subjects (491 female) were included in this analysis. Their mean (SD) age was 38 (12) years. Mean 25(OH)D was 24 ng/ml (range: 4-67) with 286 (44%) subjects found to have vitamin D deficiency (< 20 ng/ml), 234 (36%) subjects have insufficiency (20-32 ng/ml) and 128 (20%) subjects have optimal concentrations (> 32 ng/ml). 25(OH)D concentrations were significantly higher in local indigenous UAE subjects compared to other Arab expatriates (p = 0.071). Although there were no statistically significant differences in clinical markers between groups, however, utra-sensitive C-reactive protein (us-CRP), parathyroid hormone (PTH), body mass index (BMI) and the bone markers U-PYD and PYD/CR were higher in vitamin D deficient older subjects aged ≥50 years and female subjects younger than 50 years respectively compared to those with insufficiency or optimal concentrations (p value < 0.05. Multiple logistic regression analysis revealed significant and independent association between 25(OH)D status and age and sex (p < 0.05).

CONCLUSION

Older subjects with vitamin D deficiency have increased BMI, inflammation and PTH compared with those with insufficiency or optimal concentrations. Co-existence of obesity and vitamin D deficiency may have increased adverse health effects.

Vitamin D Effects on Selected Anti-Inflammatory and Pro-Inflammatory Markers of Obesity-Related Chronic Inflammation

BACKGROUND

Obesity is related to changes in adipokine secretion, activity of adipose tissue macrophages, helper T cells, and regulatory T cells. It has been confirmed that vitamin D has potent anti-inflammatory properties. It contributes to reduction in pro-inflammatory mediators and an increase in anti-inflammatory cytokines. There is also evidence that vitamin D could decrease C-reactive protein (CRP) and affect selected haematological indices.

AIM OF THE STUDY

We aimed to evaluate the effect of vitamin D on interleukin (IL)-10, IL-17, CRP, blood leukocyte profile, and platelet (PLT) count in overweight and obese children before and after six months of vitamin D supplementation.

MATERIAL AND METHODS

The study group consisted of 67 overweight and obese children aged 9.08-17.5 years. The control group included 31 normal weight peers age- and sex-matched. None of the studied children had received vitamin D supplementation before the study. Data were analyzed at baseline and after vitamin D supplementation.

RESULTS

The study group had lower baseline 25(OH)D (p<0.001) and higher white blood cell (WBC) (p=0.014), granulocyte (p=0.015), monocyte (p=0.009) and CRP (p=0.002) compared to the control group. In the study group, vitamin D levels were related negatively to nutritional status. Leukocyte profile parameters, PLT, CRP, IL-10 or IL-17 were not related to baseline 25(OH)D. Baseline IL-17 levels correlated with monocytes (R= 0.36, p=0.003) independently on 25(OH)D deficit. In children with vitamin D <15ng/ml, the baseline 25(OH)D was related to CRP (R=-0.42, p=0.017). After six months of vitamin D supplementation, we noticed a decrease in CRP levels (p=0.0003). Serum 25(OH)D correlated with IL-10 in that period (R=0.27, p=0.028). Moreover, we noticed that IL-10 correlated with monocyte (R=-0.28, p=0.023). We did not find any significant associations between 25(OH)D and leukocyte profile parameters, PLT, or IL-17. The multivariable stepwise regression analysis identified IL-10 as the parameter positively associated with 25(OH)D.

CONCLUSIONS

Our study confirmed beneficial effects of vitamin D supplementation in overweight and obese paediatric populations. Vitamin D intake seems to exert its anti-inflammatory effect mainly via decreasing the CRP level and protecting stabile values of IL-10, rather than its impact on pro-inflammatory factors such as lL-17 and leukocyte profile parameters.

The Role of Vitamin D Supplementation in Children with Autism Spectrum Disorder: A Narrative Review

Children with autism spectrum disorder (ASD) present with persistent deficits in both social communication and interactions, along with the presence of restricted and repetitive behaviors, resulting in significant impairment in significant areas of functioning. Children with ASD consistently reported significantly lower vitamin D levels than typically developing children. Moreover, vitamin D deficiency was found to be strongly correlated with ASD severity. Theoretically, vitamin D can affect neurodevelopment in children with ASD through its anti-inflammatory properties, stimulating the production of neurotrophins, decreasing the risk of seizures, and regulating glutathione and serotonin levels. A Title/Abstract specific search for publications on Vitamin D supplementation trials up to June 2021 was performed using two databases: PubMed and Cochrane Library. Twelve experimental studies were included in the synthesis of this review. Children with ASD reported a high prevalence of vitamin D deficiency or insufficiency. In general, it was observed that improved vitamin D status significantly reduced the ASD severity, however, this effect was not consistently different between the treatment and control groups. The variations in vitamin D dose protocols and the presence of concurrent interventions might provide an explanation for the variability of results. The age of the child for introducing vitamin D intervention was identified as a possible factor determining the effectiveness of the treatment. Common limitations included a small number of participants and a short duration of follow-ups in the selected studies. Long-term, well-designed randomized controlled trials are warranted to confirm the effect of vitamin D on severity in children with ASD.

Randomized trial of vitamin D versus placebo supplementation on markers of systemic inflammation in hypertensive patients

BACKGROUND AND AIMS

Animal and cell models indicated that vitamin D modulates inflammatory activity, which is considered relevant in the pathogenesis of arterial hypertension and cardiovascular diseases. We therefore aimed to investigate the effect of vitamin D supplementation on systemic markers of inflammation in a cohort of hypertensive patients.

METHODS AND RESULTS

The Styrian Vitamin D Hypertension Trial is a single-centre, double-blind, placebo-controlled study conducted from 2011 to 2014 in Austria. We enrolled 200 study participants with arterial hypertension and 25-hydroxy-vitamin-D (25(OH)D) concentration below 30 ng/mL. Study participants were randomized to receive either 2800 IU of vitamin D₃ per day or placebo for 8 weeks. The present investigation is a post-hoc analysis using analysis of co-variance (ANCOVA). Outcome measures were biomarkers of inflammation including CRP, leukocytes including subtypes and leukocyte-to-lymphocyte ratio, leucine and kynurenic acid. A total of 187 participants (mean age 60.1 ± 11.3years; 47% women; mean baseline 25(OH)D 21.1 ± 5.6 ng/mL) completed the trial. ANCOVA revealed a mean treatment effect for none of the respective outcomes and no significant results were detected in various subgroup analyses.

CONCLUSION

Vitamin D₃ supplementation in hypertensive patients with insufficient 25(OH)D concentrations has no significant effect on lowering markers of systemic inflammation. Further studies investigating the effect of vitamin D on other inflammatory pathways and in populations with severe vitamin D deficiency and a significant inflammatory burden are required.

REGISTRATION

ClinicalTrials.gov Identifier: NCT02136771; EudraCT No. 2009-018,125-70. Start Date: 2011-04-06.

Water, sanitation, and hygiene as a priority intervention for stunting in under-five children in northwest Ethiopia: a community-based cross-sectional study

Background

Stunting was a significant public health problem for under-five in developing countries including Ethiopia. Globally, it was estimated 21.9% or 149 million (81.7 million in Asia and 58.8 million in Africa) under-five children stunted in 2018. In East Africa, 24 million are stunted which is the highest-burden from African regions. Hence, this study aimed to assess the prevalence of stunting and its association with Water Sanitation and Hygiene (WASH) in northwestern Ethiopia.

Method

A community-based cross-sectional study design was conducted among 630 participants from December to mid-January 2019. From five kebeles, two were selected by a simple random sampling technique for the study. To reach study participants a systematic sampling technique was used. Data were collected by using an observational checklist, pretested questionnaire, and anthropometric measurement. Anthropometric indicator, height-for-age was determined using the current World Health Organization (WHO) growth standards. Multivariable logistic regression analysis was computed to analyze the data. From the multivariable analysis the Adjusted Odds Ratio (AOR) with 95% Confidence Interval (CI) and P-value < 0.05 were used to declare statistical significance.

Result

The prevalence of stunting among under-five children was 35.6% (95%CI; 31.9–39.5%). The result from this study showed that having illiterate father and mother, give birth before marriage (single), large family size, short maternal height, unimproved drinking water source, unimproved sanitation, poor hygienic practice, having diarrhea in the previous 2 weeks before the data collection, method of child feeding, age at which complementary feeding started, frequency of feeding, not deworming and mothers who had antenatal care visit of fewer than three times were statistically associated with stunting.

Conclusion

In this study, stunting was an important public health problem among under-five children. It remains the same as the national average prevalence of Ethiopia. To alleviate this problem proper family planning utilization, good dietary intake, maternal and paternal education, and WASH interventions are critical.

The effects of vitamin D supplementation on inflammatory biomarkers in patients with abnormal glucose homeostasis: A systematic review and meta-analysis of randomized controlled trials

FINDINGS

on the level of inflammatory cytokines following vitamin D supplementation among individuals with abnormal glucose homeostasis (AGH) are controversial. Therefore, the present study was conducted on AGH patients to assess the impact of vitamin D on inflammatory cytokines such as CRP, TNF-α and IL-6. A systematic search up to September 2020 was performed through PubMed and Scopus databases. All clinical studies which evaluated the effect of oral vitamin D supplementation on inflammation in patients with AGH were included. The random-effects model was applied to obtain pooled results. For dose-response analysis, we used a fractional polynomial model. Overall, 38 studies, with 46 effect sizes, were included in this study. Combining effect sizes, we found that vitamin D considerably decrease serum concentrations of CRP (weight mean difference (WMD): - 0.67 mg/l; 95%CI: - 0.92, - 0.43; P < 0.001), IL-6 (WMD: -1.93 pg/mL; 95%CI: -2.80, -1.07; P < 0.001) and TNF-α (WMD: -0.81 pg/mL; 95%CI: -1.59, -0.03; P = 0.04). In the dose-response analysis, we failed to find any correlation between dosage of supplements and inflammatory biomarkers concentrations. Summarizing earlier studies, we demonstrated that circulating concentrations of inflammatory cytokines such as CRP, TNF-α, and IL-6 might be decreased following vitamin D supplementation among individuals with AGH.

Prevalence and predictors of vitamin D deficiency in young African children

BACKGROUND

Children living in sub-Saharan Africa have a high burden of rickets and infectious diseases, conditions that are linked to vitamin D deficiency. However, data on the vitamin D status of young African children and its environmental and genetic predictors are limited. We aimed to examine the prevalence and predictors of vitamin D deficiency in young African children.

METHODS

We measured 25-hydroxyvitamin D (25(OH)D) and typed the single nucleotide polymorphisms, rs4588 and rs7041, in the GC gene encoding the vitamin D binding protein (DBP) in 4509 children aged 0-8 years living in Kenya, Uganda, Burkina Faso, The Gambia and South Africa. We evaluated associations between vitamin D status and country, age, sex, season, anthropometric indices, inflammation, malaria and DBP haplotypes in regression analyses.

RESULTS

Median age was 23.9 months (interquartile range [IQR] 12.3, 35.9). Prevalence of vitamin D deficiency using 25(OH)D cut-offs of < 30 nmol/L and < 50 nmol/L was 0.6% (95% CI 0.4, 0.9) and 7.8% (95% CI 7.0, 8.5), respectively. Overall median 25(OH)D level was 77.6 nmol/L (IQR 63.6, 94.2). 25(OH)D levels were lower in South Africa, in older children, during winter or the long rains, and in those with afebrile malaria, and higher in children with inflammation. 25(OH)D levels did not vary by stunting, wasting or underweight in adjusted regression models. The distribution of Gc variants was Gc1f 83.3%, Gc1s 8.5% and Gc2 8.2% overall and varied by country. Individuals carrying the Gc2 variant had lower median 25(OH)D levels (72.4 nmol/L (IQR 59.4, 86.5) than those carrying the Gc1f (77.3 nmol/L (IQR 63.5, 92.8)) or Gc1s (78.9 nmol/L (IQR 63.8, 95.5)) variants.

CONCLUSIONS

Approximately 0.6% and 7.8% of young African children were vitamin D deficient as defined by 25(OH)D levels < 30 nmol/L and < 50 nmol/L, respectively. Latitude, age, season, and prevalence of inflammation and malaria should be considered in strategies to assess and manage vitamin D deficiency in young children living in Africa.

Risks of aflatoxin exposure among adolescents in boarding schools in Kilimanjaro region, Tanzania

School feeding in low-income countries is dominated by cereals and legumes, which are susceptible to aflatoxin contamination but are usually not assessed for aflatoxins. A cross sectional study was conducted to assess aflatoxin exposure among adolescents through consumption of school meals in Kilimanjaro region. Food frequency questionnaires and 24 h dietary recalls were used to collect information on food consumption. At least four samples of common food used in school meals were collected. A deterministic approach was used to estimate the dietary aflatoxin exposure. High Performance Liquid chromatography (HPLC) was used to analyse presence of aflatoxin contamination. Results showed that, maize based food and beans were consumed on daily basis. The intake of maize flour and dehulled maize ranged from 17.5 to 738.2 g and 28.2 to 272 g per person per day respectively. Furthermore, consumption of beans and rice were in the range of 121.1 to 595.2 g and 15.7 to 42.2 g per person per day respectively. Total aflatoxins ranged 0.20-438.53 μg/kg (median 2.30 μg/kg). The highest contamination range (0.59-438.53 μg/kg) was in maize while the lowest (0.20-3.41 μg/kg) was found in rice. Similarly, the highest aflatoxin B1 (AFB1) concentration (35.88 μg/kg) was in dehulled maize while the lowest (0.44 μg/kg) was in rice. The highest dietary exposure to total aflatoxins and AFB1 due to consumption of maize ranged from 0.70 to 973.45 ng/kg/bodyweight (bw)/day, and from 0.05-81.06 ng/kg/bw/day, respectively. This pronounced risk of exposure to aflatoxins might have been contributed by a monotonous maize based diet in boarding schools. These findings call for institutions immediate interventions, such as the use of appropriate storage technologies, sorting, cleaning and winnowing in order to remove damaged grains, thereby reducing the risk of dietary exposure to aflatoxins. Likewise, the relevant ministries should consider food diversification and routine risk assessments of the susceptible crops throughout the value chain as a long-term intervention plan at policy level.

Does Evidence Exist to Blunt Inflammatory Response by Nutraceutical Supplementation during COVID-19 Pandemic? An Overview of Systematic Reviews of Vitamin D, Vitamin C, Melatonin, and Zinc

More than one year has passed since the first cases of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome (SARS)-CoV-2 coronavirus were reported in Wuhan (China), rapidly evolving into a global pandemic. This infectious disease has become a major public health challenge in the world. Unfortunately, to date, no specific antivirals have been proven to be effective against COVID-19, and although a few vaccines are available, the mortality rate is not decreasing but is still increasing. One therapeutic strategy has been focused on infection prevention and control measures. In this regard, the use of nutraceutical supports may play a role against some aspect of the infection, particularly the inflammatory state and the immune system function of patients, thus representing a strategy to control the worst outcomes of this pandemic. For this reason, we performed an overview including meta-analyses and systematic reviews to assess the association among melatonin, vitamin C, vitamin D, zinc supplementation and inflammatory markers using three databases, namely, MEDLINE, PubMed Central and the Cochrane Library of Systematic Reviews. According to the evidence available, an intake of 50,000 IU/month of vitamin D showed efficacy in CRP. An amount of 1 to 2 g per day of vitamin C demonstrated efficacy both in CRP and endothelial function, and a dosage of melatonin ranging from 5 to 25 mg /day showed good evidence of efficacy in CRP, TNF and IL6. A dose of 50 mg/day of elemental zinc supplementation showed positive results in CRP. Based on the data reported in this review, the public health system could consider whether it is possible to supplement the current limited preventive measures through targeted nutraceutical large-scale administration.

Relationship between vitamin D status and clinical outcomes in dogs with a cranial cruciate ligament rupture

Cranial cruciate ligament rupture (CCLR) is one of the most common orthopaedic disorders diagnosed in dogs yet the factors which influence postoperative clinical outcomes are poorly understood. Low vitamin D status has been linked to poorer clinical outcomes in human patients undergoing elective orthopaedic surgery. The aim of this study was to examine the relationship between pre-operative vitamin D status, as defined by serum 25 hydroxyvitamin D (25(OH)D) concentrations, and initial disease severity and clinical outcomes in dogs undergoing surgical treatment for a CCLR. Serum 25(OH)D concentrations were measured in 44 dogs with a CCLR on the day before surgery. C-reactive protein concentrations were measured at a median time of 1 day post-surgery and the patient's clinical and radiographic response to CCLR surgical treatment was assessed at a median timepoint of 60 days post-surgery. Serum 25(OH)D concentrations in dogs with a CCLR was not significantly different to a population of healthy dogs (median 74.1 nmol/L and 88.40 nmol/L, respectively). There was no significant correlation between pre-operative serum 25(OH)D concentrations and length of pre-diagnosis clinical signs, pre-operative lameness scores or day 1 post-operative CRP concentrations. Thirty nine of the 44 dogs were re-examined at a median 60 days post-surgery. There was no relationship between the day 60 lameness scores and pre-operative serum 25(OH)D concentrations. In summary, we discovered that the vitamin D status of dogs with a CCLR was not significantly lower than healthy dogs and pre-operative serum 25(OH)D concentrations were not correlated to either pre-surgical disease severity or post-operative clinical outcomes.

The short-term effects of COVID-19 outbreak on dietary diversity and food security status of Iranian households (A case study in Tehran province)

Currently, the COVID-19 outbreak is spreading fast in 185 countries and has engaged most people around the world. COVID-19 imposes severe and tragic consequences on people's health due to the high rate of spread and potentially fatal impacts. In this study, the association of socio-economic factors with food security and dietary diversity is assessed before and during the COVID-19 pandemic. Data from 299 respondents were collected by an online standard questionnaire. Household Dietary Diversity Score (HDDS) and Household Food Insecurity Access Scale (HFIAS) were calculated. A multinomial regression model was applied to determine factors associated with HDDS and HFIAS before and during COVID-19 outbreak. Food security of Iranian households improved during the initial COVID-19 pandemic period (P < 0.001). Households reduced consumption of some food groups during the COVID-19 pandemic compared to the pre-COVID-19 period. Key socio-economic factors associated with food insecurity during the COVID-19 pandemic included personal savings, household income, employment status of head of household, and nutrition knowledge of head of household. During the COVID-19 outbreak, household size, head of household's occupation, personal savings, and number of male children were significantly associated with dietary diversity. Distributing free food baskets to poor households, extending e-marketing, providing nutrition consultations, and organizing donations to support infected households may increase household dietary diversity and improve food security status during a pandemic such as COVID-19. Vulnerable populations in countries experiencing food insecurity, such as Iran, should be supported - not just by providing medical care and personal protective equipment, but also with flexible safety nets and food-based intervention programs to respond to population needs.

Community-based nutrition-sensitive approach to address short-term hunger and undernutrition among primary school children in rural areas in a developing country setting: lessons from North and North-Eastern Uganda

BACKGROUND

Undernutrition in childhood is an important factor that greatly impedes the achievement of full human potential at adulthood. Despite increased enrolment of pupils in primary schools in developing countries, short-term hunger and undernutrition continue to impact negatively on school attendance, retention and education outcomes in economically disadvantaged rural areas. This study examined the feasibility of a community-based participatory action research approach building capacity of rural women food vendors to use local food resources to produce nutritionally enhanced food products for primary school feeding in rural localities in a developing country setting.

METHODS

Mixed methods approach incorporating focus group discussions (FGDs) to evaluate parents' and school administrators' perceptions of the community-based approach, participatory experimental improvement of nutritional quality of an energy-based cassava product (gari) involving community women food vendors, and cross-sectional acceptability assessment of improved products among rural primary school children. Qualitative content analysis, one-way analysis of variance and correlation analysis was used to analyse FGD data, compare nutritional profile and consumer sensory profile of different products, and examine associations between sensory attributes and acceptability of the products, respectively.

RESULTS

The approach of using local food resources to produce nutritious products targeting school feeding was strongly recognised by parents, school administrators, teachers and small scale rural women food vendors as an adoptable nutrition-sensitive means of addressing short-term hunger among primary school children in rural settings. The action research resulted in a highly accepted nutritionally enhanced product (consisting of cassava, soy and silver fish) exhibiting superior nutritional properties (23.29% protein, 90.5 g/100 g calcium, 4.5 g/100 g zinc, 11.6 g/100 g iron, 40.40 g/100 g phosphorus, 61.57 μg/100 g vitamin A) compared to the original energy-dominated cassava product (2.18% Protein, 55.6 g/100 g calcium, 1.2 g/100 g zinc, 4.4 g/100 g iron, 6.6 g/100 g phosphorus, 11.23 μg/100 g vitamin A) (p < 0.05). Nutritional computation revealed that serving 120 g of the new product would suffice to meet 30% of the recommended dietary allowance for essential nutrients that children should receive from school meals.

CONCLUSION

Community-level nutrition-sensitive innovation using local foods resources offers the opportunity for rural women food vendors to contribute to addressing short-term hunger and undernutrition challenges in primary schools in economically-disadvantaged localities in developing countries.

Sunlight and health: shifting the focus from vitamin D3 to photobiomodulation by red and near-infrared light

Both sun exposure and serum vitamin D levels have been associated with lower risks of all-cause mortality and chronic age-related diseases, e.g., cancer, diabetes and cardiovascular disease, in epidemiological studies. These associations have mainly been ascribed to beneficial effects of vitamin D. However, a vast body of randomized controlled trials (RCTs) and Mendelian randomization studies have failed to confirm any major health benefits from vitamin D supplementation. In this review, we present tentative evidence showing that red and near-infrared light, both being present in sunlight, could explain the associations between sunlight exposure and better health status. Body irradiation with red and near-infrared light, usually termed as photobiomodulation (PBM), has demonstrated beneficial effects in animal models of chronic diseases. Beyond this, preliminary evidence from RCTs suggest potential clinical benefit from PBM for chronic diseases. PBM is currently being investigated in many pre-registered clinical trials, results of which will eventually clarify the role of red and near-infrared light in the prevention and treatment of common age-related chronic diseases.

Could vitamin D reduce obesity-associated inflammation? Observational and Mendelian randomization study

BACKGROUND

Obesity is associated with inflammation but the role of vitamin D in this process is not clear.

OBJECTIVES

We aimed to assess the associations between serum 25-hydroxyvitamin D [25(OH)D], BMI, and 16 inflammatory biomarkers, and to assess the role of vitamin D as a potential mediator in the association between higher BMI and inflammation.

METHODS

Northern Finland Birth Cohort 1966 (NFBC1966) 31-y data on 3586 individuals were analyzed to examine the observational associations between BMI, 25(OH)D, and 16 inflammatory biomarkers. Multivariable regression analyses and 2-sample regression-based Mendelian randomization (MR) mediation analysis were performed to assess any role of vitamin D in mediating a causal effect of BMI on inflammatory biomarkers [soluble intercellular adhesion molecule 1 (sICAM-1), high sensitivity C-reactive protein (hs-CRP), and α1-acid glycoprotein (AGP)] for which observational associations were detected. For MR, genome-wide association study summary results ranging from 5163 to 806,834 individuals were used for biomarkers, 25(OH)D, and BMI. Findings were triangulated with a literature review of vitamin D supplementation trials.

RESULTS

In NFBC1966, mean BMI (kg/m2) was 24.8 (95% CI: 24.7, 25.0) and mean 25(OH)D was 50.3 nmol/L (95% CI: 49.8, 50.7 nmol/L). Inflammatory biomarkers correlated as 4 independent clusters: interleukins, adhesion molecules, acute-phase proteins, and chemokines. BMI was positively associated with 9 inflammatory biomarkers and inversely with 25(OH)D (false discovery rate < 0.05). 25(OH)D was inversely associated with sICAM-1, hs-CRP, and AGP, which were positively associated with BMI. The MR analyses showed causal association of BMI on these 3 inflammatory biomarkers. There was no observational or MR evidence that circulating 25(OH)D concentrations mediated the association between BMI and these 3 inflammatory markers. Review of randomized controlled trials (RCTs) supported our findings showing no impact of vitamin D supplementation on inflammatory biomarkers.

CONCLUSIONS

The findings from our observational study and causal MR analyses, together with data from RCTs, do not support a beneficial role of vitamin D supplementation on obesity-related inflammation.