Effect of sunlight exposure on serum 25-hydroxyvitamin d concentration in women with vitamin d deficiency: using ambulatory lux meter and sunlight exposure questionnaire

Effect of Vitamin D on Paraxonase-1, Total Antioxidant Capacity, and 8-Isoprostan in Children with Attention Deficit Hyperactivity Disorder

METHOD

In this double-blind, randomized, placebo-controlled trial, 75 children (aged 6-12) diagnosed with ADHD were randomly assigned into two groups. The supplementation group received vitamin D3 (2000 IU), and the control group received a placebo for 3 months. Blood samples were collected at baseline and after intervention to analyze the 25(OH)D, paraxonase-1 activity (PON-1), Total Antioxidant Capacity (TAC), and 8-isoprostan levels.

RESULTS

A significant rise in circulating 25(OH)D was observed in the vitamin D group versus the placebo group at the end of the study. There was no reduction in 8-isoprostan levels in the vitamin D group compared to the placebo group. Serum paraxonase-1 and TAC concentration decreased in both groups, but these alterations were not statistically significant in the treatment group versus the placebo group at the end of the intervention.

CONCLUSION

Vitamin D supplementation for 3 months did not have beneficial effects on biomarkers of oxidative stress status. To confirm these findings, further studies on children are suggested.

Effect of Vitamin D Supplementation on Inflammatory Biomarkers in School-Aged Children with Attention Deficit Hyperactivity Disorder

METHOD

This randomized double-blind, placebo-controlled trial was conducted on 75 school-aged children with a diagnosis of ADHD based on DSM-V criteria. Children were randomly allocated to receive either vitamin D3 (2000 IU/day) or a placebo for 3 months. Serum IL-6, TNF-α, and 25(OH) D were assessed before and after the intervention to determine the effects of vitamin D on the highlighted parameters.

RESULTS

Serum levels of 25(OH) D increased significantly in the vitamin D group (P=0.01). However, no significant differences in serum IL-6 and TNF-α were found between both groups at the baseline and at the end of the intervention.

CONCLUSION

The findings revealed that vitamin D supplementation for 3 months is not efficacious in reducing inflammatory cytokines in children with ADHD. Further studies are required to confirm these results.

Vitamin D status, vitamin D intake, and sunlight exposure in adults adhering or not to periodic religious fasting for decades

We investigated whether periodic abstinence from foods of animal origin and a conservative lifestyle, with reduced sunlight exposure, affect vitamin D status. In a cross-sectional design, we measured the serum 25-hydroxyvitamin D concentration and assessed dietary vitamin D intake and sunlight exposure in 200 adults adhering to religious fasting for decades and in 200 non-fasters, with no differences between groups in bone mineral density. Fasters showed lower 25-hydroxyvitamin D concentration than non-fasters in winter and spring. Vitamin D intake and some indices of sunlight exposure (including two related to winter and spring) were lower in fasters, and 378 of the 400 participants exhibited vitamin D insufficiency or deficiency. In conclusion, individuals following a religious lifestyle had lower vitamin D intake, sunlight exposure and, at times, serum 25-hydroxyvitamin D concentration than controls, although these differences did not impact bone health.

Can Current Recommendations on Sun Exposure Sufficiently Increase Serum Vitamin D Level?: One-Month Randomized Clinical Trial

BACKGROUND

Lack of sunlight exposure is the primary reason for the worldwide epidemic of vitamin D deficiency. Although recommended sunlight exposure guidelines exist, there is no evidence regarding whether current guidelines are optimal for increasing vitamin D levels among individuals with vitamin D deficiency.

METHODS

Sixty Korean adults aged 20-49 years with serum 25-hydroxyvitamin D (25[OH]D) levels of < 20 ng/mL were randomly assigned to three groups: sunlight exposure (n = 20), vitamin D supplementation groups (n = 20), and daily living (n = 20) for 1 month. The sunlight exposure group had sunlight exposure on 20% to 30% of their body surface areas for 30-60 minutes per day, 3 times a week during the summer season. Vitamin D supplementation was prescribed with 800 IU/day of vitamin D. The serum levels of 25(OH)D were measured at baseline and at 1-month follow-up examinations.

RESULTS

The largest change in serum 25(OH)D was observed among the vitamin D supplementation group (+3.5 ng/mL, P < 0.001). The sunlight exposure group showed a slight increase in serum 25(OH)D level, but the absolute increase was less than one-third that of the vitamin D supplementation group (+0.9 ng/mL, P = 0.043). Only two participants in the sunlight exposure reached serum concentrations of 25(OH)D ≥ 20 ng/mL at follow-up. The daily living group showed no difference in vitamin D levels (-0.7 ng/mL, P = 0.516).

CONCLUSION

Sunlight exposure was not sufficient to overcome vitamin D insufficiency or deficiency in the current study subjects. Effectiveness of current sunlight exposure guidelines among various populations should be reassessed in larger clinical studies.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0002671.

Effect of solar ultraviolet radiation exposure on serum 25(OH)D concentration: a pilot randomised controlled trial

Sunlight generates vitamin D, but there are scant human data from randomised trials on which to base health policy advice about how much sun exposure is necessary to change 25(OH)D concentrations. The purpose of the study was to evaluate the feasibility of using solar ultraviolet (UV) radiation exposure to generate a change in 25(OH)D concentration in a randomised controlled trial (RCT). The intervention tested in this RCT was supervised exposure to one standard erythemal dose (SED; 100 J m-2) of solar UV radiation three days per week for three weeks with approximately 35% of the body surface area not covered by clothing. Thirty-six fair-skinned (skin type II and III) indoor workers from Brisbane, Australia were randomised into either the intervention group (n = 16) or the control group (n = 20); the latter did not receive any supervised sun exposure. We asked both groups to use sunscreen and to minimise time outdoors during the study period. We collected blood samples at baseline, once per week during the three week intervention period, and four weeks after the intervention finished. The cumulative UV radiation exposure over the intervention period measured using polysulphone badges was higher in the intervention group than in the control group (median 8 vs. 4 SEDs, p = 0.14). After three weeks, the mean serum 25(OH)D concentration increased from 60 to 65 nmol l-1 in the intervention group and from 55 to 57 nmol l-1 in the control group. After adjustment for baseline 25(OH)D, the mean change per week during the intervention phase was non-significantly higher in the intervention than in the control group (0.7 vs. 0.3; p = 0.35). This difference was not sustained during the follow-up period. Large field trials are needed to inform policy about how much natural sun exposure is required to raise 25(OH)D concentrations. This pilot identified key issues that need to be considered in the design of such a trial.

25-Hydroxyvitamin D levels and bone mineral density evaluation in patients with cholecystectomy: a case-control study

This study compared the 25-hyrdoxyvitamin (OH) D and bone mineral density (BMD) values of patients with and without cholecystectomy. Although 25(OH) D levels were significantly lower in the cholecystectomy group (12.1 ± 6.2 vs. 15.6 ± 6.6 ng/mL), no significant difference was observed between the groups in terms of BMD measurements.

INTRODUCTION

Although 25 (OH) D levels were studied and found to be lower in patients with cholecystectomy, the data is scarce as regards the BMD. Therefore, the aim of this study was to compare the 25(OH) D and BMD values of patients with cholecystectomy and without cholecystectomy.

METHODS

This study was a single-center and case-control trial. The cholecystectomy group comprised the patients with a history of cholecystectomy. In addition, a healthy control group without history of cholecystectomy was defined. All patients were selected consecutively from the patients who admitted to the outpatient clinics of physical and rehabilitation medicine or internal medicine between the June 2016 and August 2016. The patients were ambulatory and did not receive any osteoporosis treatment before. Chemiluminescence microparticle immunoassay method was used for 25(OH) D measurements. Dual-energy X-ray absorptiometry was used for the BMD evaluations.

RESULTS

There were 46 patients in the cholecystectomy group with a mean age of 58.6 ± 14.1 years and 64 patients in the control group with a mean age of 59.2 ± 13.3 years. Although 25(OH) D levels were significantly lower in the cholecystectomy group (12.1 ± 6.2 vs. 15.6 ± 6.6 ng/mL) (p =  0.010), no significant difference was observed between the groups in terms of BMD measurements (p > 0.05). While there was a weak positive correlation between the BMI and BMD measurements (all p < 0.05), linear regression analyses showed that the models were not valid (femoral neck R = 0.092; femur total R = 0.170; and lumbar total R = 0.199). No significant difference was observed between the BMD measurements and time after cholecystectomy in the cholecystectomy group (p > 0.05).

CONCLUSION

In the light of our results, cholecystectomy patients seem to have lower level of 25(OH) D levels in comparison with healthy subjects, but both groups have similar BMD values. Further studies in cohort designs taking into account the bone formation and resorption markers are awaited.

Inadequate sunlight exposure in patients with inflammatory bowel disease

OBJECTIVE

Inadequate sun exposure impairs vitamin D activity and favors low bone density, especially in patients at increased risk for osteoporosis, such as those affected by inflammatory bowel disease (IBD). In this study, sun exposure was investigated in a large series of patients with IBD in a Mediterranean country, Italy, where this risk is considered less likely to occur than in higher latitudes.

METHODS

This is a case-control study of 292 patients with IBD [132 with Crohn's disease (CD) and 160 with ulcerative colitis (UC)], 80 diseased and 540 healthy controls, conducted via a validated questionnaire to quantify sunlight exposure. Data were also compared with controls matched by age and gender.

RESULTS

In total 78 of the 292 patients with IBD had low, 169 had moderate and 45 had high exposure to sunlight, significantly differing from controls (P < 0.001). The 132 patients with CD were more likely to have abnormal levels of sunlight exposure (49 low, 72 moderate and 11 high) than those with UC (29 low, 97 moderate and 34 high) (P < 0.001). The controls were significantly more exposed to sunlight than both men and women with IBD (P < 0.001 and 0.004, respectively).

CONCLUSIONS

IBD patients are significantly less exposed to sunlight than matched controls in Italy, often to an extent that may impair vitamin D activation. Increasing responsible sunlight exposure, thus promoting adequate vitamin D concentrations, may prove beneficial in IBD, in geographical areas in which this risk factor is not generally taken into consideration.

Vitamin D-binding protein, vitamin D status and serum bioavailable 25(OH)D of young Asian Indian males working in outdoor and indoor environments

Urban Asian Indians generally have low serum 25(OH)D. Information on serum bioavailable 25(OH)D and the effect of prolonged sun-exposure in them is not known. We assessed serum 25(OH)D and bioavailable 25(OH)D in males with varying durations of sun-exposure in Delhi during August-September. Serum 25(OH)D, vitamin D-binding protein (DBP), bioavailable 25(OH)D, free 25(OH)D index, iPTH, ionized calcium and sun-index were assessed in outdoor, mixed outdoor-indoor and indoor workers (n = 88, 32 and 74, respectively). The mean sun-index (12.0 ± 6.25, 4.3 ± 2.20 and 0.7 ± 0.62, respectively; P < 0.001) was highest outdoors and lowest indoors. Serum 25(OH)D (29.0 ± 8.61, 19.1 ± 5.73 and 10.9 ± 4.19 ng/ml, respectively; P < 0.001), bioavailable 25(OH)D and free 25(OH)D index were maximum in outdoor workers followed by mixed-exposure and indoor workers. Their mean serum DBP levels (241.2 ± 88.77, 239.3 ± 83.40 and 216.6 ± 63.93 µg/ml, respectively; P = 0.12) were comparable. Mean serum iPTH was significantly lower in outdoor than indoor workers and showed inverse correlations with serum 25(OH)D, bioavailable 25(OH)D and free 25(OH)D index (r = -0.401, -0.269 and -0.236, respectively; P < 0.001 in all). Daily dietary-calorie intake was higher and calcium lower in outdoor than indoor workers. On regression analysis, sun-exposure was the only significant variable, increasing serum 25(OH)D by 2.03 ng/ml per hour of sun-exposure (95 % confidence interval 1.77-2.28; P < 0.001). Outdoor workers with prolonged sun-exposure were vitamin D-sufficient, with higher serum bioavailable 25(OH)D than the indoor workers during summer. Use of serum DBP levels did not affect the interpretation of their vitamin D status.

Correlation of objectively measured light exposure and serum vitamin D in men aged over 60 years

Diminished vitamin D is common among older individuals. Sunlight contributes more to vitamin D synthesis than diet or supplementation. This study examined associations between objectively measured light exposure, vitamin D serum levels, and bone biomarkers in 100 men aged over 60 years. Light exposure was measured in lux via Actigraph monitors for 1 week. Significantly, greater levels of vitamin D were observed in participants with higher light exposure. Seasonal differences in lux were also noted. Significant differences in bone markers were not found. Objective measurement of light exposure is an inexpensive, simple, and effective way to address vitamin D deficiency.

Vitamin D deficiency in non-alcoholic fatty liver disease: The chicken or the egg?

BACKGROUND & AIMS

Serum vitamin D concentration is reduced in patients with non-alcoholic fatty liver disease (NAFLD). Although the mechanism of vitamin D deficiency in liver disease is not fully understood, a few reports have suggested the beneficial effects of vitamin D supplements. The present study investigated changes in serum 25-hydroxy vitamin D level and clinical parameters after total calorie restriction with vitamin D intake reduction in NAFLD patients.

METHODS

Newly diagnosed NAFLD patients with elevated aminotransferase levels were chosen for a calorie restriction and weight-reduction program. A total of 82 patients received nutritional education from nutritionists every 2 weeks for 2 months. Serum 25-hydroxy vitamin D level, amount of vitamin D intake, and physical activity were thoroughly investigated.

RESULTS

The mean serum 25-hydroxy vitamin D concentration was 13.0 ng/ml. Twenty-nine patients (35.4%) had severe vitamin D deficiency. Patients with a 25-hydroxy vitamin D concentration <10 ng/ml had an increased risk of abdominal obesity (72.4% vs. 47.2%, P = 0.023) and a higher prevalence of metabolic syndrome (69% vs. 42.2%, P = 0.015) compared with patients with 25-hydroxy vitamin D levels >10 ng/ml. Although total energy and vitamin D intake were reduced during the program, serum 25-hydroxy vitamin D levels increased in patients with NAFLD (P < 0.001). Liver enzymes and metabolic parameters also improved, even as vitamin D intake decreased. Serum vitamin D concentration increased with body weight and intrahepatic fat reduction, independent of decreases in vitamin D intake.

CONCLUSIONS

Weight loss per increased serum vitamin D level without vitamin D supplementation and improved metabolic parameters in NAFLD.

Environmental factors and multiple sclerosis severity: a descriptive study

Growing evidence suggests that environmental factors play a key role in the onset of multiple sclerosis (MS). This study was conducted to examine whether environmental factors may also be associated with the evolution of the disease. We collected data on smoking habits, sunlight exposure and diet (particularly consumption of vitamin D-rich foods) from a sample of 131 MS patients. We also measured their serum vitamin D concentration. The clinical impact of MS was quantified using the Multiple Sclerosis Severity Score (MSSS); MS was considered “severe” in patients with MSSS ≥ 6, and “mild” in patients with MSSS ≤ 1. The results showed a strong association between serum vitamin D concentration and both sunlight exposure (26.4 ± 11.9 ng/mL vs. 16.5 ± 12.1 ng/mL, p = 0.0004) and a fish-rich diet (23.5 ± 12.1 ng/mL vs. 16.1 ± 12.4 ng/mL, p = 0.005). Patients reporting frequent sunlight exposure had a lower MSSS (2.6 ± 2.4 h vs. 4.6 ± 2.6 h, p < 0.001). The mild MS patients reported much more frequent sunlight exposure (75% mild MS vs. 25% severe MS p = 0.004, Chi square test). A higher serum vitamin D concentration determined a lower risk of developing severe MS, adjusted for sunlight exposure (OR = 0.92 for one unit increase in vitamin D, 95% CI: 0.86–0.97, p = 0.005). A stronger inverse association emerged between frequent sunlight exposure and the risk of severe MS (OR = 0.26, 95% CI: 0.09–0.71, p = 0.009). Our data show that an appropriate diet and adequate expose to sunlight are associated with less aggressive MS.

Effect of adiposity, season, diet and calcium or vitamin D supplementation on the vitamin D status of healthy urban African and Asian-Indian adults

Vitamin D deficiency has been implicated in the aetiology of infectious diseases and metabolic syndrome. These diseases are prevalent in the African and Asian-Indian populations of South Africa; however, there is limited data on 25-hydroxyvitamin D (25(OH)D) concentrations in these populations. The aim of the present study was to assess the vitamin D status and its predictors in healthy adults in Johannesburg. We assessed the vitamin D status of 730 adult African and Asian-Indian subjects residing in Johannesburg. The contributions of sun exposure, season, dietary intake of Ca and vitamin D, total body fat and body fat distribution to 25(OH)D concentrations were assessed. The concentrations of 25(OH)D were measured by HPLC. The contribution of 25(OH)D₃ to total 25(OH)D concentrations was assessed. The mean age of the subjects was 42·6 (SD 13·1) years (range: 18-65). Concentrations of 25(OH)D < 30 nmol/l were found in 28·6 % of the Asian-Indian subjects in comparison with 5·1 % of the African subjects (P< 0·0001). Parathyroid hormone (PTH) concentrations were negatively associated with 25(OH)D concentrations, while season and sun exposure were positive predictors explaining 16 % of the variance in 25(OH)D concentrations (P< 0·0001) in the African subjects. In the Asian-Indian subjects, PTH concentrations were negatively associated with 25(OH)D concentrations, while male sex, season and Ca supplementation were positive predictors and explained 17 % of the variance in 25(OH)D concentrations (P< 0·0001). In the multivariate regression analysis, neither total body fat nor body fat distribution was predictive of 25(OH)D concentrations in either group. In conclusion, factors such as sun exposure, dietary supplement use and ethnicity are important determinants of plasma 25(OH)D concentrations.