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Al-Saoodi H, Kolahdooz F, Andersen JR, Jalili M. Effect of vitamin D on inflammatory and clinical outcomes in patients with rheumatoid arthritis: a systematic review and dose-response meta-analysis of randomized controlled trials. Nutr Rev 2024; 82:600-611. [PMID: 37437898 DOI: 10.1093/nutrit/nuad083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023] Open
Abstract
CONTEXT Rheumatoid arthritis is a chronic inflammatory disease that causes synovitis. Vitamin D deficiency is common in rheumatoid arthritis. OBJECTIVE This systematic review and meta-analysis investigated whether vitamin D supplementation affects the inflammatory and clinical outcomes in patients with rheumatoid arthritis on the basis of randomized clinical trials. DATA SOURCES A literature search was performed in the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, MEDLINE, Embase, and Google Scholar for articles published until May 2022. DATA EXTRACTION The studies were selected according to PRISMA guidelines, and the risk of bias was assessed for randomized controlled trials. DATA ANALYSIS A random effects model was used to conduct a meta-analysis, and heterogeneity was assessed using the I2 statistic. Of 464 records, 11 studies were included from 3049 patients. Conclusion: Vitamin D supplementation did not significantly reduce C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), disease activity score in 28 joints (DAS28), or the health assessment questionnaire score; however, the response to supplementation was highly heterogeneous. The pooled analysis showed that vitamin D significantly reduced the pain-visual analogue scale (VAS) weighted mean difference (WMD = -1.30, 95% confidence interval [CI] [-2.34, -27], P = .01), DAS28-CRP (WMD = -.58, 95% CI [-.86, -.31], P < .0001), and DAS28-ESR (WMD = -.58, 95% CI [-.86, -.31], P = .0001). Subgroup analysis for vitamin D doses (>100 µg per day versus <100 µg per day) showed that the higher doses had a more significant effect on CRP than the lower doses (P < .05). CONCLUSIONS There was no significant difference between the effect of 2 vitamin D doses on ESR and DAS28. To minimize the high heterogeneity among studies in this meta-analysis, other confounding factors such as baseline vitamin D, age, dietary vitamin D, time of year, sun exposure, drug interaction, effect dosage, and power of study should be examined.
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Affiliation(s)
- Hagir Al-Saoodi
- Preventive and Clinical Nutrition Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Frederiksberg C, Denmark
| | - Fariba Kolahdooz
- Indigenous Global Health Research Group, Department of Medicine, College of Health Sciences, University of Alberta, Edmonton, Canada
| | - Jens Rikardt Andersen
- Preventive and Clinical Nutrition Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Frederiksberg C, Denmark
| | - Mahsa Jalili
- Preventive and Clinical Nutrition Group, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Frederiksberg C, Denmark
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Goyal A, Dabas A, Shah D, Malhotra RK, Dewan P, Madhu SV, Gupta P. Sunlight Exposure vs Oral Vitamin D Supplementation for Prevention of Vitamin D Deficiency in Infancy: A Randomized Controlled Trial. Indian Pediatr 2022. [DOI: 10.1007/s13312-022-2642-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Cho SH, Yun JM, Lee JE, Lee H, Joh HK, Cho B. Comparison of Two Strategies to Increase Serum Vitamin D Levels in a Real-World Setting: Sunlight Exposure and Oral Supplementation. J Nutr Sci Vitaminol (Tokyo) 2022; 67:384-390. [PMID: 34980716 DOI: 10.3177/jnsv.67.384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Sunlight exposure and oral supplementation are the key strategies to increase serum 25-hydroxyvitamin D [25(OH)D] concentration. We aimed to determine elevation in serum 25(OH)D levels by comparing sunlight exposure and oral vitamin D supplementation in vitamin D-deficient participants who chose the treatment strategy by shared decision-making. We enrolled 197 participants aged ≥19 y who had vitamin D deficiency (serum 25(OH)D<20 ng/mL). Participants selected their treatment method through shared decision-making by preference: sunlight exposure or 1,000 IU oral vitamin D3 supplementation daily. Changes in serum 25(OH)D concentration and duration of sunlight exposure were evaluated after 3 mo. Among 197 participants, 26 (13%) selected sunlight exposure and 171 (87%) selected oral vitamin D supplementation. Seasonal distribution of participants and follow-up rate after 3 mo were not significantly different. There was no significant increase in mean serum 25(OH)D levels in the sunlight exposure group. Conversely, the mean serum 25(OH)D level increased by 11 ng/mL after 3 mo in the oral vitamin D supplementation group. The duration of mean sunlight exposure per day during the study period was not significantly different between the groups. Oral supplementation with 1,000 IU vitamin D3 daily significantly increased serum 25(OH)D levels in vitamin D-deficient participants after 3 mo, while sunlight exposure did not. This study suggests that oral supplementation is more effective than sun exposure in increasing vitamin D levels in the Korean population. Therefore, new recommendations on maintaining adequate vitamin D levels are needed in the Korean population.
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Affiliation(s)
- Su Hwan Cho
- Department of Family Medicine, Seoul National University Hospital
| | - Jae Moon Yun
- Department of Family Medicine, Seoul National University Hospital.,Center for Health Promotion and Optimal Aging of Seoul National University Hospital in Korea
| | - Ji Eun Lee
- Department of Family Medicine, Seoul National University Hospital
| | - Hyejin Lee
- Department of Family Medicine, Seoul National University Bundang Hospital
| | - Hee-Kyung Joh
- Department of Family Medicine, Seoul National University Hospital.,Department of Medicine, Seoul National University College of Medicine.,Department of Family Medicine, Seoul National University Health Service Center
| | - Belong Cho
- Department of Family Medicine, Seoul National University Hospital.,Center for Health Promotion and Optimal Aging of Seoul National University Hospital in Korea.,Department of Family Medicine, Seoul National University College of Medicine
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Webb AR, Alghamdi R, Kift R, Rhodes LE. 100 YEARS OF VITAMIN D: Dose-response for change in 25-hydroxyvitamin D after UV exposure: outcome of a systematic review. Endocr Connect 2021; 10:R248-R266. [PMID: 34519278 PMCID: PMC8558903 DOI: 10.1530/ec-21-0308] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 09/13/2021] [Indexed: 12/14/2022]
Abstract
A systematic review of publications addressing change in vitamin D status (25-hydroxyvitamin D (25OHD)) after exposure to UV radiation identified 2001 independent peer-reviewed publications. Of these, 21 used artificial sources of UV radiation, met all inclusion criteria and were quality assured; 13 publications used solar radiation and met sufficient inclusion criteria to be retained as supporting evidence; 1 further included publication used both solar and artificial sources. The review consistently identified that low dose, sub-erythemal doses are more effective for vitamin D synthesis than doses close to a minimum erythema dose; increasing skin area exposed increases the amount of vitamin D synthesised although not necessarily in a linear manner; constant dosing leads to a dose-dependent plateau in 25OHD, and dose-response is greatest at the start of a dosing regime; there is a large interpersonal variation in response to UV exposure. Fourteen of the studies using artificial sources of radiation were used to determine a dose-response relationship for change in 25OHD on whole-body exposure to repeated sub-erythemal doses of UV radiation, taking the form Δ25OHD (nmol/L) = A ln(standard vitamin D dose) + B. This helps quantify our understanding of UV as a source of vitamin D and enables exposure regimes for safe synthesis of vitamin D to be assessed. Specific studies of people with pigmented skin (Fitzpatrick skin types 5 and 6) were rare, and this dose-response relationship is only applicable to white-skinned individuals as skin type is a determinant of response to UV radiation. Findings provide information for vitamin D guidance updates.
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Affiliation(s)
- Ann R Webb
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, UK
| | - Rehab Alghamdi
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, UK
- Department of Clinical Nutrition, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Richard Kift
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, UK
| | - Lesley E Rhodes
- Centre for Dermatology Research, School of Biological Sciences, The University of Manchester and Salford Royal NHS Foundation Trust, Manchester, UK
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5
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Nikooyeh B, Neyestani TR. Contribution of vitamin D status as a determinant of cardiometabolic risk factors: a structural equation model, National Food and Nutrition Surveillance. BMC Public Health 2021; 21:1819. [PMID: 34627185 PMCID: PMC8501625 DOI: 10.1186/s12889-021-11839-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 09/22/2021] [Indexed: 11/18/2022] Open
Abstract
Background Structural equation modeling (SEM) is a method used to evaluate linear causal relationships among variables. This study aimed to investigate the direct and indirect effects of serum 25(OH) D on certain cardiovascular risk factors using SEM. Methods An analytical cross-sectional study was conducted in six provinces of Iran. Subjects (n = 922), aged 19–65 years, were selected from National Food and Nutrition Surveillance. The assessments were sun-exposure behavior, anthropometric and biochemical measurements. A series of SEM models were tested and the model with the best fit indices was considered for use in the structural part of the model. Based on the literature review of previous theoretical models and supporting bivariate analyses, an overall SEM examined direct or indirect associations among observed and latent variables. We put the demographic, duration of sun exposure, anthropometric and metabolic variables in our model. Results The paths between serum 25(OH) D and BMI were inverse and statistically significant, whereas age showed a positive association with BMI (B = 0.06, p < 0.001), both direct (st. effect = 0.11, p = 0.01) and indirect via vitamin D (st. effect = − 0.02, p = 0.01). The results confirmed that serum 25(OH) D concentration is a predictor for latent variable of lipid profile (B = − 0.13, p = 0.01) both through direct (p = 0.02) and indirect effects via BMI (p = 0.01). Conclusion Serum 25(OH) D concentration is a predictor of BMI and also a latent variable of lipid profile via direct and indirect effects. It can also attenuate the harmful effect of age on BMI and lipid profile particularly in women.
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Affiliation(s)
- Bahareh Nikooyeh
- National Nutrition and Food Technology Research Institute and Faculty of Nutrition Science and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, 1981619573, Iran
| | - Tirang R Neyestani
- National Nutrition and Food Technology Research Institute and Faculty of Nutrition Science and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, 1981619573, Iran.
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Yu J, He X, Huang S. The establishment of serum 25-hydroxyvitamin D reference intervals in children aged 0-14 years in Zigong area, China. J Physiol Anthropol 2021; 40:14. [PMID: 34615548 PMCID: PMC8495952 DOI: 10.1186/s40101-021-00265-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/27/2021] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE To establish the reference interval of serum 25-hydroxyvitamin D (25(OH)D) in apparently healthy children in Zigong, China, using an indirect method to provide a basis for proper clinical diagnosis and treatment. METHODS A total of 1851 apparently healthy children of the Children's Health Care Department in Zigong First People's Hospital between January 2016 and December 2020 were included in the study. The Kolmogorov-Smirnov test was used to analyze the data for normality, and the non-normally distributed data were transformed into approximately normal distribution by Blom's normal rank transformation, and the transformed data were excluded from outliers by the quartile spacing method, and the data were stratified and analyzed according to sex, age, and season. The data were stratified according to sex, age, and season, and the area between the 2.5% and 97.5% percentile points was used as the reference interval. RESULTS The serum 25(OH)D data were non-normally distributed. The data were normally distributed after Blom's normality rank transformation, and 92 cases of outliers were excluded from the transformed data according to the interquartile spacing method. The differences in serum 25(OH)D levels between sex were not statistically significant (P > 0.05), and there was no need to establish reference intervals based on sex. There was no statistically significant difference in serum 25-hydroxyvitamin D levels between winter and spring, and also no difference between summer and autumn (P > 0.05), and the levels were lower in winter-spring than in summer-autumn. Comparison between age groups showed that there was no statistically significant difference in serum 25(OH)D levels between the < 6 months group and the 6 ~ 11 months group, and between the 6 ~ 9 years group and the 10 ~ 14 years group (P > 0.05); serum 25(OH)D levels decreased with increasing age. There was an interactive effect of season and age group on 25(OH)D levels, and the corresponding reference intervals were established according to different seasons and age groups. In summer and autumn, the reference intervals of serum 25(OH)D for < 1 year, 1 ~ 2 years, 3 ~ 5 years, and 6 ~ 14 years were 39.86 ~ 151.43, 31.54 ~ 131.65, 22.05 ~ 103.75, and 15.36 ~ 85.53 ng/ml and 24.42 ~ 144.20, 31.54 ~ 131.65, 16.80 ~ 165.68, and 15.46 ~ 85.54 ng/ml in winter and spring, respectively. CONCLUSION Reference intervals for serum 25(OH)D in children of different seasons and ages in Zigong, China, were established to provide a reference for clinical disease diagnosis, treatment, and prognosis determination.
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Affiliation(s)
- Jianhong Yu
- Department of Clinical Laboratory, Zigong First People's Hospital, Zigong, China.
| | - Xiaoping He
- Department of Clinical Laboratory, Zigong First People's Hospital, Zigong, China
| | - Shengwei Huang
- Department of Nuclear Medicine, Zigong First People's Hospital, Zigong, China
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Cai B, Luo X, Zhang P, Luan Y, Cai X, He X. Effect of vitamin D supplementation on markers of cardiometabolic risk in children and adolescents: A meta-analysis of randomized clinical trials. Nutr Metab Cardiovasc Dis 2021; 31:2800-2814. [PMID: 34353700 DOI: 10.1016/j.numecd.2021.06.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND AIMS An increasing attention to the effect of vitamin D supplementation on cardiometabolic risk markers in children and adolescents has been gained recently. However, the results are inconsistent. Therefore, we conducted a meta-analysis to examine the effect of vitamin D supplementation on cardiometabolic risk markers in children and adolescents. METHODS AND RESULTS Eligible randomized controlled trials (RCTs) were identified by searching PubMed, EMBASE and Web of Science. The results of this study are synthetized and reported in accordance with the PRISMA statement. GRADE system was used to assess the certainty of evidence. A total of 9 RCTs were identified and included in the meta-analysis. We found that vitamin D supplementation did not affect the changes of cardiometabolic risk markers including high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglycerides (TG), body mass index (BMI), waist circumferences, systolic blood pressure (SDP) and diastolic blood pressure (DBP). However, vitamin D supplementation showed a beneficial effect on fasting glucose (MD, -1.54 mg/dl, 95% CI -2.98 to -0.10) and TG (MD, -24.76 mg/dl, 95% CI -37.66 to -11.86) in the sub-group analysis of total vitamin D supplementation ≥ 200,000 IU. CONCLUSIONS Vitamin D supplementation appeared to have a beneficial effect on reducing fasting glucose and TG level when total vitamin D supplementation ≥200,000 IU but not HDL-C, LDL-C TC, blood pressure and waist circumferences levels in children and adolescents. Further studies are needed to address this issue.
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Affiliation(s)
- Bin Cai
- Department of Quality Management, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Shaoxing People's Hospital, Shaoxing, China
| | - Xi Luo
- Department of Clinical Nutrition, Tongde Hospital of Zhejiang Province, Hangzhou, China
| | - Pianhong Zhang
- Department of Clinical Nutrition, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
| | - Yi Luan
- Department of Cardiovascular, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xueli Cai
- Department of Quality Management, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiaoming He
- The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
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Kowalówka M, Główka AK, Karaźniewicz-Łada M, Kosewski G. Clinical Significance of Analysis of Vitamin D Status in Various Diseases. Nutrients 2020; 12:E2788. [PMID: 32933052 PMCID: PMC7551674 DOI: 10.3390/nu12092788] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/03/2020] [Accepted: 09/08/2020] [Indexed: 12/17/2022] Open
Abstract
Vitamin D plays a role not only in the proper functioning of the skeletal system and the calcium-phosphate equilibrium, but also in the immune system, the cardiovascular system and the growth and division of cells. Although numerous studies have reported on the analysis of vitamin D status in various groups of patients, the clinical significance of measurements of vitamin D forms and metabolites remains ambiguous. This article reviews the reports analyzing the status of vitamin D in various chronic states. Particular attention is given to factors affecting measurement of vitamin D forms and metabolites. Relevant papers published during recent years were identified by an extensive PubMed search using appropriate keywords. Measurement of vitamin D status proved to be a useful tool in diagnosis and progression of metabolic syndrome, neurological disorders and cancer. High performance liquid chromatography coupled with tandem mass spectrometry has become the preferred method for analyzing the various forms and metabolites of vitamin D in biological fluids. Factors influencing vitamin D concentration, including socio-demographic and biochemical factors as well as the genetic polymorphism of the vitamin D receptor, along with vitamin D transporters and enzymes participating in vitamin D metabolism should be considered as potential confounders of the interpretation of plasma total 25(OH)D concentrations.
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Affiliation(s)
- Magdalena Kowalówka
- Department of Bromatology, Poznan University of Medical Sciences, 42 Marcelińska Street, 60-354 Poznań, Poland; (M.K.); (A.K.G.); (G.K.)
| | - Anna K. Główka
- Department of Bromatology, Poznan University of Medical Sciences, 42 Marcelińska Street, 60-354 Poznań, Poland; (M.K.); (A.K.G.); (G.K.)
| | - Marta Karaźniewicz-Łada
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Święcickiego Street, 60-781 Poznań, Poland
| | - Grzegorz Kosewski
- Department of Bromatology, Poznan University of Medical Sciences, 42 Marcelińska Street, 60-354 Poznań, Poland; (M.K.); (A.K.G.); (G.K.)
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Śliwicka E, Cisoń T, Straburzyńska-Lupa A, Pilaczyńska-Szcześniak Ł. Effects of whole-body cryotherapy on 25-hydroxyvitamin D, irisin, myostatin, and interleukin-6 levels in healthy young men of different fitness levels. Sci Rep 2020; 10:6175. [PMID: 32277130 PMCID: PMC7148349 DOI: 10.1038/s41598-020-63002-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 03/24/2020] [Indexed: 12/11/2022] Open
Abstract
Skeletal muscle and adipose tissue play an important role in maintaining metabolic homeostasis and thermogenesis. We aimed to investigate the effects of single and repeated exposure to whole-body cryotherapy in volunteers with different physical fitness levels on 25-hydroxyvitamin D (25(OH)D) and myokines. The study included 22 healthy male volunteers (mean age: 21 ± 1.17 years), who underwent 10 consecutive sessions in a cryogenic chamber once daily (3 minutes, −110 °C). Blood samples were collected before and 30 minutes and 24 hours after the first and last cryotherapy sessions. Prior to treatment, body composition and physical fitness levels were measured. After 10 cryotherapy treatments, significant changes were found in myostatin concentrations in the low physical fitness level (LPhL) group. The 25(OH)D levels were increased in the high physical fitness level (HPhL) group and decreased in the LPhL group. The HPhL group had significant changes in the level of high-sensitivity interleukin-6 after the first treatment. The LPhL group had significant changes in 25(OH)D, irisin, and myostatin levels after the tenth treatment. Our data demonstrated that in healthy young men, cryotherapy affects 25(OH)D levels, but they were small and transient. The body’s response to a series of 10 cryotherapy treatments is modified by physical fitness level.
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Affiliation(s)
- Ewa Śliwicka
- Poznan University of Physical Education, Department of Physiology and Biochemistry, Poznań, Poland.
| | - Tomasz Cisoń
- State University of Applied Science in Nowy Sącz, Department of Physiotherapy, Nowy Sącz, Poland
| | - Anna Straburzyńska-Lupa
- Poznan University of Physical Education, Department of Physical Therapy and Sports Recovery, Poznań, Poland
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Moradi S, Shahdadian F, Mohammadi H, Rouhani MH. A comparison of the effect of supplementation and sunlight exposure on serum vitamin D and parathyroid hormone: A systematic review and meta-analysis. Crit Rev Food Sci Nutr 2019; 60:1881-1889. [PMID: 31107101 DOI: 10.1080/10408398.2019.1611538] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Background: Supplementation and getting sunlight exposure are two treatments for vitamin D deficiency. However, studies reported conteroversial findings regarding the efficacy of these two methods.Objective: To compare the effect of oral vitamin D supplementation with sunlight exposure on serum vitamin D and parathyroid hormone (PTH).Methods: A computer-based literature search through PubMed, Scopus and Google scholar search engines was conducted until April 2019 to find clinical trials which compared the effect of oral vitamin D supplementation with sunlight exposure on serum vitamin D and PTH. Means for serum 25-hydroxy vitamin D3 (25(OH) D3) and PTH concentration were extracted. A subgroup analysis was used to detect potential sources of inter-study heterogeneity. Mean differences (MD) were analyzed using a random-effects model (the DerSimonian-Laird approach).Results: A total of seven papers were included in the meta-analysis. Pooled analysis showed that vitamin D supplementation significantly elevated levels of serum 25(OH) D3 in comparison with sunlight exposure (MD: 8.56nmol/l, 95%CI: 4.15, 12.97, T2 = 40.32%, H2 = 9.45%, P for heterogeneity p < 0.001). Also, the difference between the effect of vitamin D supplementation and sun exposure was lower in studies which used UVB radiation compared with studies which applied direct sunlight (MD: 11.65 nmol/l, 95%CI: 7.02, 16.28; P for between subgroup heterogeneity = 0.001).Conclusion: Vitamin D supplementation was more effective than sun exposure at increasing serum 25(OH) D3. The difference between efficacy of vitamin D supplementation and sun exposure was lower in studies which used long-term sun exposure or applied UVB treatment instead of direct sunlight.
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Affiliation(s)
- Sajjad Moradi
- Student Research Committee, Department of Clinical Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Farnaz Shahdadian
- Food Security Research Center and Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hamed Mohammadi
- Student Research Committee, Department of Clinical Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Hossein Rouhani
- Food Security Research Center and Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran
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