Vitamin D for prevention of respiratory tract infections: A systematic review and meta-analysis
ABSTRACT To explore the effect of vitamin D supplementation in prevention of respiratory tract infections on the basis of published clinical trials.
Clinical trials were searched from various electronic databases. Five clinical trials were suitable for inclusion. Outcome was events of respiratory tract infections in vitamin D group and placebo group. Data was reported as odds ratio with 95% confidence interval. Both random and fixed model was used for analysis. Analysis was done with the help of Comprehensive meta-analysis software 2.
Events of respiratory tract infections were significantly lower in vitamin D group as compared to control group [Odds ratio = 0.582 (0.417 - 0.812) P = 0.001] according to random model. Results were similar in fixed model. On separate analysis of clinical trials dealing with groups of children and adults, beneficial effect of vitamin D was observed in both, according to fixed model [Odds ratio = 0.579 (0.416 - 0.805), P = 0.001 and Odd ratio = 0.653 (0.472 - 0.9040, P = 0.010 respectively]. On using random model beneficial effect persisted in children's group but became nonsignificant in adults group [Odds ratio = 0.579 (0.416 - 0.805), P = 0.001 and Odd ratio = 0.544 (0.278 - 1.063) P = 0.075 respectively].
Vitamin D supplementation decreases the events related to respiratory tract infections. There is need of more well conducted clinical trials to reach to a certain conclusion.
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- "In addition to promoting the absorption of calcium and phosphorus in the mucosa of small intestine and regulating the deposition and release of bone calcium, it can also participate in the differentiation and regulation of the immune system to play its biological activity. Related reports indicate that the immune mechanism of bronchial asthma is regulated by many factors, and the 1,25-(OH) 2 D 3 can improve the symptoms of chronic airway inflammation in asthma, with a significant negative correlation between them     . There is close relationship between the type I allergy and the incidence of asthma. "
ABSTRACT: To explore the effect of 1,25-dihydroxyvitamin D3 on the mast cell tryptase (MCT) in asthmatic guinea pigs. A total of 60 male or female healthy guinea pigs were randomly divided into control group (group A), asthmatic group (group B), and 1,25-dihydroxyvitamin D3 group (group C), with 20 cases in each group. To establish asthmatic guinea pig models, 1 mL peanut oil was filled into stomach in the morning in group A and group B, and 1 mL peanut oil with 1,25-dihydroxyvitamin D3 was filled into stomach in group C. Airway resistance (Re) of asthmatic guinea pigs was detected, and the bronchoalveolar lavage fluid (BALF) cells were counted. Lung tissue with HE and MCT immunohistochemical staining were used to observe the pathological changes in lung tissue and the distribution of MCT. After injection of different concentration of acetylcholine chloride, the Re in group B and group C were increased significantly compared with group A (P < 0.05); compared with group B, the Re in group C were decreased significantly (t = -5.385, -5.761, -6.184, -13.574, P < 0.05); the total number of BALF cells and eosinophils were increased significantly in group B and C (t = 19.618, 9.598, 10.854, 5.388, P < 0.05); compared with group B, the total number of BALF cells and eosinophils in group C was decreased significantly (t = -5.555, -5.392, P < 0.05); the number of tryptase positive cells in group B was increased significantly than that in group A (t = 21.312, P < 0.05), and in addition to the alveolar septum and submucosa, the cells were also distributed around blood vessels and outside the cells; the number of tryptase positive cells in group C was decreased significantly compared with group B, and the difference was statistically significant (t = 5.043, P < 0.05). After the asthmatic guinea pigs are treated with 1,25-dihydroxyvitamin D3, their BALF, Re, infiltration degree of inflammatory cells in the trachea and lung tissue and airway inflammatory reaction are reduced significantly. 1,25-dihydroxyvitamin D3 has a certain inhibiting effect on the activation of mast cells and the release of MCT granules. Copyright © 2015 Hainan Medical College. Production and hosting by Elsevier B.V. All rights reserved.Asian Pacific Journal of Tropical Medicine 06/2015; 7(6). DOI:10.1016/j.apjtm.2015.05.006 · 0.93 Impact Factor
- "Patients who showed prehospital vitamin concentrations of less than 10 ng/mL were significantly correlated with increased odds of developing HABSI . A meta-analysis published by Charan et al. (2012) evaluated five clinical trials. The outcome events were URTIs in the vitamin D group and the placebo group. "
Article: Vitamin D and respiratory infections[Show abstract] [Hide abstract]
ABSTRACT: Vitamin D or 1,25-hydroxyvitamin D (1,25(OH)2 D) has a well-established role in calcium homeostasis. In recent years, the discovery of vitamin D-metabolizing enzymes and vitamin D receptor (VDR) in the lungs and various cells of the immune system has led to numerous studies conducted to evaluate its role in respiratory functions and, in particular, upper respiratory tract infections (URTIs). A PubMed literature search was done using vitamin D and respiratory infections as key words. Only clinical studies were considered. This study aimed to review recent clinical and epidemiological studies conducted in adults and children, and to evaluate the functional role of vitamin D in respiratory infections. The evaluated studies show an important immunomodulatory role of vitamin D, which reduces the incidence and risk of URTIs, both in children and in adults. Combating URTIs can be done prophylactically, associating the use of vaccines against Streptococcus pneumoniae with strengthening the immune system through supplementation with vitamin D. These actions can significantly contribute to reducing the number of URTIs, the use of antibiotics, and consequently, the rates of antimicrobial resistance.The Journal of Infection in Developing Countries 04/2015; 9(04). DOI:10.3855/jidc.5711 · 1.14 Impact Factor
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- "" This health claim is targeting men and women 60 years of age and older and the dose required is a daily consumption of 800 IU vitamin D, which can come from all sources. Further emerging vitamin D health relationships include physiological parameters like improved immune response (Baeke et al., 2010; Schwalfenberg, 2011; Hewison, 2012; White, 2012), improved respiratory health(Berry et al., 2011; Charan et al., 2012; Choi et al., 2013; Hirani, 2013) possibly also relate to reduced tuberculosis incidence (Nnoaham and Clarke, 2008; Martineau et al., 2011; Mitchell et al., 2011; Coussens et al., 2012; Salahuddin et al., 2013; Huaman et al., 2014); and reduced risk to develop autoimmune diseases like multiple sclerosis (Solomon and Whitham, 2010; Cantorna, 2012; Dobson et al., 2013) or type 1 diabetes (Hypponen et al., 2001; Holick, 2003; Ramos-Lopez et al., 2006; Baeke et al., 2010; De Boer et al., 2012; Dong et al., 2013; Van Belle et al., 2013). In chronic, non-communicable diseases, vitamin D deficiency is being discussed to possibly ameliorate the incidence of some neoplastic diseases like colorectal, lung, prostate, and breast cancers (Ng et al., 2008; Rosen et al., 2012; Welsh, 2012; Cheng et al., 2013); cardiovascular diseases (CVDs) including hypertension, myocardial infarction, stroke (Forman et al., 2007; Giovannucci et al., 2008; Gardner et al., 2011; Bischoff-Ferrari et al., 2012; Tamez and Thadhani, 2012; Karakas et al., 2013; Pilz et al., 2013a; Schroten et al., 2013); life-style diseases like obesity and type 2 diabetes (Pittas et al., 2007; González-Molero et al., 2012; Khan et al., 2013; Pilz et al., 2013b; Schottker et al., 2013; Tsur et al., 2013; Van Belle et al., 2013; Bouillon et al., 2014); diseases related to the decline in sight function including age-related macular degeneration (Parekh et al., 2007; Millen et al., 2011; Lee et al., 2012); and neurological disorders including Alzheimer and Parkinson disease (Buell and Dawson-Hughes, 2008; Annweiler et al., 2012; Eyles et al., 2013; Zhao et al., 2013). "
ABSTRACT: Vitamin D is a micronutrient that is needed for optimal health throughout the whole life. Vitamin D3 (cholecalciferol) can be either synthesized in the human skin upon exposure to the UV light of the sun, or it is obtained from the diet. If the photoconversion in the skin due to reduced sun exposure (e.g. in wintertime) is insufficient, intake of adequate vitamin D from the diet is essential to health. Severe vitamin D deficiency can lead to multitude of avoidable illnesses; among them are well known bone diseases like osteoporosis, a number of autoimmune diseases, many different cancers and some cardiovascular diseases like hypertension are being discussed. Vitamin D is found naturally in only very few foods. Foods containing vitamin D include some fatty fish, fish liver oils, and eggs from hens that have been fed vitamin D and some fortified foods in countries with respective regulations. Base on geographic location or food availability adequate vitamin D intake might not be sufficient on a global scale. The International Osteoporosis Foundation (IOF) has collected the 25-hydroxy-vitamin D plasma levels in populations of different countries using published data and developed a global vitamin D map. This map illustrates the parts of the world, where vitamin D did not reach adequate 25-hydroxyvitamin D plasma levels: 6.7 % of the papers report 25-hydroxyvitamin D plasma levels below 25 nmol/L, which indicates vitamin D deficiency, 37.3 % are below 50 nmol/Land only 11.9% found 25-hydroxy-vitamin D plasma levels above 75 nmol/L target as suggested by vitamin D experts. The vitamin D map is adding further evidence to the vitamin D insufficiency pandemic debate, which is also an issue in the developed world. Besides malnutrition, a condition where the diet does not match to provide the adequate levels of nutrients including micronutrients for growth and maintenance, we obviously have a situation where enough nutrients were consumed, but lacked to reach sufficient vitamFrontiers in Physiology 07/2014; 5:248. DOI:10.3389/fphys.2014.00248 · 3.53 Impact Factor