Reductions in body weight and percent fat mass increase the vitamin D status of obese subjects: a systematic review and metaregression analysis

Background: Recent studies have demonstrated the role of micronutrients in the manifestation of comorbidities associated with obesity. Vitamin D deficiency, in particular, appears to be associated with increased levels of inflammatory markers, which may lead to chronic low-grade inflammation, elevating the risk of chronic diseases such as diabetes, metabolic syndrome, and cardiovascular disease. The objective of this study was to perform a systematic review of observational studies conducted to investigate the effect of vitamin D deficiency on inflammatory markers in obese subjects. Methodology: This systematic review was conducted in accordance with the “STROBE” and PRISMA recommendations. Observational studies that evaluated the effect of vitamin D status on inflammatory markers in obese subjects were selected and reviewed. Searches were conducted in the PubMed, SciVerse Scopus, and Web of Science databases from February 21 to 22, 2018. Results: After the selection and removal of duplicate articles, 10 eligible articles were identified. Results from eight observational studies showed an association between vitamin D deficiency or insufficiency in the body and increased concentrations of inflammatory markers in obese individuals. On the other hand, two of the studies did not demonstrate any correlation. With regard to the inflammatory markers evaluated, eight studies showed high concentrations of ultra-sensitive C-reactive protein, five studies found an increase in interleukin-6 concentrations, and two studies noted increased levels of tumor necrosis factor. Conclusion: The data presented in this systematic review provide evidence of the association between vitamin D deficiency and increased inflammation in obesity.

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Vitamin D status of the African-Caribbean population globally: A Systematic Review and Meta-Analysis

10.26226/morressier.5ef37080b2a27f760262bb26 ◽

2020 ◽

Author(s):

Rebecca Vearing

Keyword(s):

Systematic Review ◽

Vitamin D ◽

Meta Analysis ◽

Vitamin D Status ◽

African Caribbean ◽

Caribbean Population

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The role of vitamin D in metabolic disturbances in polycystic ovary syndrome: a systematic review

Acta Endocrinologica ◽

10.1530/eje-13-0617 ◽

2013 ◽

Vol 169 (6) ◽

pp. 853-865 ◽

Cited By ~ 57

Author(s):

Y H M Krul-Poel ◽

C Snackey ◽

Y Louwers ◽

P Lips ◽

C B Lambalk ◽

...

Keyword(s):

Systematic Review ◽

Vitamin D ◽

Clinical Trials ◽

Polycystic Ovary Syndrome ◽

Polycystic Ovary ◽

Vitamin D Status ◽

Regression Analyses ◽

Metabolic Disturbances ◽

Ovary Syndrome ◽

Weighted Means

ContextMetabolic disturbances, in particular, insulin resistance (IR) and dyslipidemia, are common in women suffering from polycystic ovary syndrome (PCOS). Evidence is accumulating that vitamin D status may contribute to the development of metabolic disturbances in PCOS.ObjectiveThe aim of this study was to carry out a systematic review addressing the association between vitamin D status, vitamin D receptor polymorphisms, and/or polymorphisms related to vitamin D metabolism and metabolic disturbances in women with PCOS.Design and methodsA systematic search of electronic databases was carried out up to January 2013 for observational studies and clinical trials in women suffering from PCOS with outcome measures that were related to vitamin D status. We conducted univariate and multivariate regression analyses of the weighted means to gain insights into the association between vitamin D, BMI, and IR based on existing literature.ResultsWe found 29 eligible trials with inconsistency in their results. One well-designed randomized controlled trial has been carried out until now. Univariate regression analyses of the weighted means revealed vitamin D to be a significant and independent predictor of IR in both PCOS and control women. The significance disappeared after adjustment for BMI in PCOS women.ConclusionsCurrent evidence suggests an inverse association between vitamin D status and metabolic disturbances in PCOS. Owing to the heterogeneity of the studies, it is hard to draw a definite conclusion. The causal relationship between vitamin D status and metabolic disturbances in PCOS remains to be determined in well-designed placebo-controlled randomized clinical trials.

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Weight and skin colour as predictors of vitamin D status: results of an epidemiological investigation using nationally representative data

Public Health Nutrition ◽

10.1017/s1368980016000173 ◽

2016 ◽

Vol 20 (10) ◽

pp. 1857-1864 ◽

Cited By ~ 5

Author(s):

Sonali Rajan ◽

Tom Weishaar ◽

Bryan Keller

Keyword(s):

Vitamin D ◽

Body Weight ◽

Skin Colour ◽

Vitamin D Status ◽

Epidemiological Investigation ◽

Dietary Recommendations ◽

Hydroxyvitamin D ◽

25 Hydroxyvitamin D ◽

Nationally Representative ◽

The Impact

AbstractObjectiveCurrent US dietary recommendations for vitamin D vary by age. Recent research suggests that body weight and skin colour are also major determinants of vitamin D status. The objective of the present epidemiological investigation was to clarify the role of age as a predictor of vitamin D status, while accounting for body weight and skin colour, among a nationally representative sample.DesignWe calculated the mean serum 25-hydroxyvitamin D levels for the US population by age and weight, as well as by weight and race/ethnicity group. Multiple regression analyses were utilized to evaluate age and weight as predictors of vitamin D status: serum 25-hydroxyvitamin D levels with age alone, age and body weight, and age, body weight and their two-way interaction were modelled for the entire sample and each age subgroup. Graphical data were developed using B-spline non-linear regression.SettingNational Health and Nutrition Examination Survey (31 934 unweighted cases).SubjectsIndividuals aged 1 year and older.ResultsThere were highly significant differences in mean vitamin D status among US residents by weight and skin colour, with those having darker skin colour or higher body weight having worse vitamin D status. Although a significant factor, the impact of age on vitamin D status was notably less than the impact of body weight.ConclusionsVitamin D status varied predominantly by body weight and skin colour. Recommendations by nutritionists for diet and supplementation needs should take this into account if vitamin D-related health disparities are to be meaningfully reduced across the USA.

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