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The Cochrane Database of Systematic... Mar 2023Phototherapy is a widely accepted, effective first-line therapy for neonatal jaundice. It is traditionally used continuously but intermittent phototherapy has been... (Review)
Review
BACKGROUND
Phototherapy is a widely accepted, effective first-line therapy for neonatal jaundice. It is traditionally used continuously but intermittent phototherapy has been proposed as an equally effective alternative with practical advantages of improved maternal feeding and bonding. The effectiveness of intermittent phototherapy compared with continuous phototherapy is unknown.
OBJECTIVES
To assess the safety and effectiveness of intermittent phototherapy compared with continuous phototherapy.
SEARCH METHODS
Searches were conducted on 31 January 2022 in the following databases: CENTRAL via CRS Web, MEDLINE and Embase via Ovid. We also searched clinical trials databases and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-randomised trials.
SELECTION CRITERIA
We included RCTs, cluster-RCTs and quasi-RCTs comparing intermittent phototherapy with continuous phototherapy in jaundiced infants (both term and preterm) up to the age of 30 days. We compared intermittent phototherapy with continuous phototherapy by any method and at any dose and duration as defined by the authors.
DATA COLLECTION AND ANALYSIS
Three review authors independently selected trials, assessed trial quality and extracted data from included studies. We performed fixed-effect analyses and expressed treatment effects as mean difference (MD), risk ratio (RR) and risk difference (RD) with 95% confidence intervals (CIs). Our primary outcomes of interest were rate of decline of serum bilirubin, and kernicterus. We used the GRADE approach to assess the certainty of evidence.
MAIN RESULTS
We included 12 RCTs (1600 infants) in the review. There is one ongoing study and four awaiting classification. There was little or no difference between intermittent phototherapy and continuous phototherapy with respect to rate of decline of bilirubin in jaundiced newborn infants (MD -0.09 micromol/L/hr, 95% CI -0.21 to 0.03; I² = 61%; 10 studies; 1225 infants; low-certainty evidence). One study involving 60 infants reported no incidence of bilirubin induced brain dysfunction (BIND). It is uncertain whether either intermittent or continuous phototherapy reduces BIND because the certainty of this evidence is very low. There was little or no difference in treatment failure (RD 0.03, 95% CI 0.08 to 0.15; RR 1.63, 95% CI 0.29 to 9.17; 1 study; 75 infants; very low-certainty evidence) or infant mortality (RD -0.01, 95% CI -0.03 to 0.01; RR 0.69, 95% CI 0.37 to 1.31 I² = 0%; 10 studies, 1470 infants; low-certainty evidence). AUTHORS' CONCLUSIONS: The available evidence detected little or no difference between intermittent and continuous phototherapy with respect to rate of decline of bilirubin. Continuous phototherapy appears to be more effective in preterm infants, however, the risks of continuous phototherapy and the potential benefits of a slightly lower bilirubin level are unknown. Intermittent phototherapy is associated with a decrease in the total number of hours of phototherapy exposure. There are theoretical benefits to intermittent regimens but there are important safety outcomes that were inadequately addressed. Large, well designed, prospective trials are needed in both preterm and term infants before it can be concluded that intermittent and continuous phototherapy regimens are equally effective.
Topics: Infant; Infant, Newborn; Humans; Jaundice, Neonatal; Phototherapy; Bilirubin; Family
PubMed: 36867730
DOI: 10.1002/14651858.CD008168.pub2 -
Effects of betaine supplementation on cardiovascular markers: A systematic review and Meta-analysis.Critical Reviews in Food Science and... 2022Controversy regarding the effects of betaine supplementation on cardiovascular markers has persisted for decades. This systematic review and meta-analysis compared the... (Meta-Analysis)
Meta-Analysis
Controversy regarding the effects of betaine supplementation on cardiovascular markers has persisted for decades. This systematic review and meta-analysis compared the effects of betaine supplementation on cardiovascular disease (CVD) markers. Studies examining betaine supplementation on CVD markers published up to February 2021 were identified through PubMed, the Cochrane Library, Web of Science, Embase, and SCOPUS. Betaine supplementation had a significant effect on concentrations of betaine (MD: 82.14 μmol/L, 95% CI: 67.09 to 97.20), total cholesterol (TC) (MD: 14.12 mg/dl, 95% CI%: 9.23 to 19.02), low-density lipoprotein (LDL) (MD: 10.26 mg/dl, 95% CI: 6.14 to 14.38)], homocysteine (WMD: -1.30 micromol/L, 95% CI: -1.61 to -0.98), dimethylglycine (DMG) (MD: 21.33 micromol/L, 95% CI: 13.87 to 28.80), and methionine (MD: 2.06 micromol/L, 95% CI: 0.23 to 3.88). Moreover, our analysis indicated that betaine supplementation did not affect serum concentrations of triglyceride (TG), high-density lipoprotein (HDL), fasting blood glucose (FBG), C-reactive protein (CRP), liver enzymes [alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT)], and blood pressure. Our subgroup analysis suggested that a maximum dose of 4 g/d might have homocysteine-lowering effects without any adverse effect on lipid profiles reported with doses of ≥4 g/d. In conclusion, the present systematic review and meta-analysis supports the advantage of a lower dose of betaine supplementation (<4 g/d) on homocysteine concentrations without the lipid-augmenting effect observed with a higher dosage.
Topics: Betaine; Biomarkers; Cardiovascular Diseases; Dietary Supplements; Homocysteine; Humans; Triglycerides
PubMed: 33764214
DOI: 10.1080/10408398.2021.1902938 -
Nutrition Reviews Dec 2019Very preterm neonates (VPNs) are unable to digest breast milk and therefore rely on parenteral nutrition (PN) formulations. This systematic review was prepared following...
CONTEXT
Very preterm neonates (VPNs) are unable to digest breast milk and therefore rely on parenteral nutrition (PN) formulations. This systematic review was prepared following PRISMA-P 2015 guidelines. For the purpose of this review, desirable mean plasma arginine concentration is defined as ≥80 micromoles/L.
OBJECTIVE
The review was performed to answer the following research question: "In VPNs, are high amounts of arginine in PN, compared with low amounts of arginine, associated with appropriate circulating concentrations of arginine?" Therefore, the aims were to 1) quantify the relationship between parenteral arginine intakes and plasma arginine concentrations in PN-dependent VPNs; 2) identify any features of study design that affect this relationship; and 3) estimate the target parenteral arginine dose to achieve desirable preterm plasma arginine concentrations.
DATA SOURCES
The PubMed, Scopus, Web of Science, and Cochrane databases were searched regardless of study design; review articles were not included.
DATA EXTRACTION
Only articles that discussed amino acid (AA) intake and measured plasma AA profile post PN in VPNs were included. Data were obtained using a data extraction checklist that was devised for the purpose of this review.
DATA ANALYSIS
Twelve articles met the inclusion criteria. The dose-concentration relationship of arginine content (%) and absolute arginine intake (mg/(kg × d)) with plasma arginine concentrations showed a significant positive correlation (P < 0.001).
CONCLUSION
Future studies using AA solutions with arginine content of 17%-20% and protein intakes of 3.5-4.0 g/kg per day may be needed to achieve higher plasma arginine concentrations.
Topics: Arginine; Dose-Response Relationship, Drug; Humans; Infant, Newborn; Infant, Premature; Parenteral Nutrition
PubMed: 31504841
DOI: 10.1093/nutrit/nuz049 -
The Cochrane Database of Systematic... Jan 2010Primary sclerosing cholangitis is a chronic cholestatic disease of intrahepatic and extrahepatic biliary ducts, characterised by chronic periductal inflammation and... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Primary sclerosing cholangitis is a chronic cholestatic disease of intrahepatic and extrahepatic biliary ducts, characterised by chronic periductal inflammation and sclerosis of the ducts, which results in segmental stenoses of bile ducts, cholestasis, fibrosis, and ultimately, liver cirrhosis. Patients with primary sclerosing cholangitis are at higher risk of cholangiocarcinoma as well as of colonic neoplasia, since primary sclerosing cholangitis is associated with inflammatory bowel disease in more than 80% of the patients. Several therapeutic modalities have been proposed for primary sclerosing cholangitis, like ursodeoxycholic acid, glucocorticosteroids, and immunomodulatory agents, but none has been successful in reversing the process of the disease. To date, liver transplantation is the only definite therapeutic solution for patients with advanced primary sclerosing cholangitis with liver cirrhosis.
OBJECTIVES
To assess the beneficial and harmful effects of glucocorticosteroids for patients with primary sclerosing cholangitis.
SEARCH STRATEGY
We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, EMBASE, and LILACS from their inception until September 2009, as well as reference lists.
SELECTION CRITERIA
Randomised clinical trials comparing any dose or duration of glucocorticosteroids versus placebo, no intervention, or other immunosuppressive agents. We included trials irrespective of language, blinding, or publication status.
DATA COLLECTION AND ANALYSIS
Authors extracted data independently and assessed the methodological quality by the generation of the allocation sequence, allocation concealment, double blinding, follow-up, incomplete outcome data reporting, selective reporting, baseline imbalance, and early stopping. The results of the meta-analyses were presented as relative risks (RR) or mean difference (MD), both with 95% confidence intervals (CI). The primary outcome measures were mortality and liver-related morbidity.
MAIN RESULTS
Two randomised clinical trials were eligible for inclusion. One trial compared biliary lavage with hydrocortisone versus saline in 17 patients. Hydrocortisone tended to increase adverse events (pancreatitis, cholangitis with septicaemia, paranoid ideas, fluid retention) (RR 3.43, 95% CI 0.51 to 22.9) and had no cholangiographic improvement, which led to termination of the trial. The other trial compared budesonide versus prednisone in 18 patients. Patients had statistically significant higher serum bilirubin concentration after treatment with prednisone compared with budesonide (MD 10.4 micromol/litre, 95% CI 1.16 to 19.64 micromol/litre). No other statistically significant effects on clinical or biochemical outcomes were reported on any of the evaluated interventions.
AUTHORS' CONCLUSIONS
There is no evidence to support or refute peroral glucocorticosteroids for patients with primary sclerosing cholangitis. The intrabiliary application of corticosteroids via nasobiliary tube seems to induce severe adverse effects.
Topics: Anti-Inflammatory Agents; Budesonide; Cholangitis, Sclerosing; Humans; Hydrocortisone; Prednisone; Randomized Controlled Trials as Topic; Therapeutic Irrigation
PubMed: 20091555
DOI: 10.1002/14651858.CD004036.pub3 -
The Cochrane Database of Systematic... Jan 2010Interleukin 2 receptor antagonists (IL2Ra) are used as induction therapy for prophylaxis against acute rejection in kidney transplant recipients. Use of IL2Ra has... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Interleukin 2 receptor antagonists (IL2Ra) are used as induction therapy for prophylaxis against acute rejection in kidney transplant recipients. Use of IL2Ra has increased steadily since their introduction, but the proportion of new transplant recipients receiving IL2Ra differs around the globe, with 27% of new kidney transplant recipients in the United States, and 70% in Australasia receiving IL2Ra in 2007.
OBJECTIVES
To systematically identify and summarise the effects of using an IL2Ra, as an addition to standard therapy, or as an alternative to another immunosuppressive induction strategy.
SEARCH STRATEGY
We searched the Cochrane Renal Group's specialised register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE to identify new records, and authors of included reports were contacted for clarification where necessary.
SELECTION CRITERIA
Randomised controlled trials (RCTs) in all languages comparing IL2Ra to placebo, no treatment, other IL2Ra or other antibody therapy.
DATA COLLECTION AND ANALYSIS
Data was extracted and assessed independently by two authors, with differences resolved by discussion. Dichotomous outcomes are reported as relative risk (RR) and continuous outcomes as mean difference (MD) with 95% confidence intervals (CI).
MAIN RESULTS
We included 71 studies (306 reports, 10,537 participants). Where IL2Ra were compared with placebo (32 studies; 5,784 patients) graft loss including death with a functioning graft was reduced by 25% at six months (16 studies: RR 0.75, 95% CI 0.58 to 0.98) and one year (24 studies: RR 0.75, 95% CI 0.62 to 0.90), but not beyond this. At one year biopsy-proven acute rejection was reduced by 28% (14 studies: RR 0.72, 95% CI 0.64 to 0.81), and there was a 19% reduction in CMV disease (13 studies: RR 0.81, 95% CI 0.68 to 0.97). There was a 64% reduction in early malignancy within six months (8 studies: RR 0.36, 95% CI 0.15 to 0.86), and creatinine was lower (7 studies: MD -8.18 micromol/L 95% CI -14.28 to -2.09) but these differences were not sustained.When IL2Ra were compared to ATG (16 studies, 2211 participants), there was no difference in graft loss at any time point, or for acute rejection diagnosed clinically, but the was benefit of ATG therapy over IL2Ra for biopsy-proven acute rejection at one year (8 studies:, RR 1.30 95% CI 1.01 to 1.67), but at the cost of a 75% increase in malignancy (7 studies: RR 0.25 95% CI 0.07 to 0.87) and a 32% increase in CMV disease (13 studies: RR 0.68 95% CI 0.50 to 0.93). Serum creatinine was significantly lower for IL2Ra treated patients at six months (4 studies: MD -11.20 micromol/L 95% CI -19.94 to -2.09). ATG patients experienced significantly more fever, cytokine release syndrome and other adverse reactions to drug administration and more leucopenia but not thrombocytopenia. There were no significant differences in outcomes according to cyclosporine or tacrolimus use, azathioprine or mycophenolate, or to the study populations baseline risk for acute rejection. There was no evidence that effects were different according to whether equine or rabbit ATG was used.
AUTHORS' CONCLUSIONS
Given a 38% risk of rejection, per 100 recipients compared with no treatment, nine recipients would need treatment with IL2Ra to prevent one recipient having rejection, 42 to prevent one graft loss, and 38 to prevent one having CMV disease over the first year post-transplantation. Compared with ATG treatment, ATG may prevent some experiencing acute rejection, but 16 recipients would need IL2Ra to prevent one having CMV, but 58 would need IL2Ra to prevent one having malignancy. There are no apparent differences between basiliximab and daclizumab. IL2Ra are as effective as other antibody therapies and with significantly fewer side effects.
Topics: Creatinine; Cytomegalovirus Infections; Glomerular Filtration Rate; Graft Rejection; Humans; Immunosuppressive Agents; Kidney Transplantation; Randomized Controlled Trials as Topic; Receptors, Interleukin-2
PubMed: 20091551
DOI: 10.1002/14651858.CD003897.pub3 -
Annals of Internal Medicine Nov 2009Intravenous sodium bicarbonate has been proposed to reduce the risk for contrast-induced nephropathy (CIN). (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Intravenous sodium bicarbonate has been proposed to reduce the risk for contrast-induced nephropathy (CIN).
PURPOSE
To determine the effect of sodium bicarbonate on the risk for CIN.
DATA SOURCES
MEDLINE, PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials from 1950 to December 2008; conference proceedings; and ClinicalTrials.gov, without language restriction.
STUDY SELECTION
Randomized, controlled trials of intravenous sodium bicarbonate that prespecified the outcome of CIN as a 25% increase in baseline serum creatinine level or an absolute increase of 44 micromol/L (0.5 mg/dL) after radiocontrast administration.
DATA EXTRACTION
Using standardized protocols, 2 reviewers serially abstracted data for each study.
DATA SYNTHESIS
23 published and unpublished trials with information on 3563 patients and 396 CIN events were included. The pooled relative risk was 0.62 (95% CI, 0.45 to 0.86), with evidence of significant heterogeneity across studies (I(2) = 49.1%; P = 0.004). Some heterogeneity was due to the difference in the estimates between published and unpublished studies: relative risk, 0.43 (CI, 0.25 to 0.75) versus 0.78 (CI, 0.52 to 1.17), respectively. Meta-regression showed that small, poor-quality studies that assessed outcomes soon after radiocontrast administration were more likely to suggest benefit (P < 0.05 for all). No clear effects of treatment on the risk for dialysis, heart failure, and total mortality were identified.
LIMITATION
Power to assess clinical end points was limited.
CONCLUSION
The effectiveness of sodium bicarbonate treatment to prevent CIN in high-risk patients remains uncertain. Earlier reports probably overestimated the magnitude of any benefit, whereas larger, more recent trials have had neutral results. Large multicenter trials are required to clarify whether sodium bicarbonate has value for prevention of CIN before routine use can be recommended.
PRIMARY FUNDING SOURCE
None.
Topics: Acetylcysteine; Contrast Media; Heart Failure; Humans; Injections, Intravenous; Kidney Diseases; Mortality; Renal Dialysis; Risk; Sodium Bicarbonate
PubMed: 19884624
DOI: 10.7326/0003-4819-151-9-200911030-00008 -
Archives of Pediatrics & Adolescent... Nov 2009To compare available nomograms in the literature defining trends in bilirubin levels across populations with different risk factor profiles and to study a mathematical... (Review)
Review
OBJECTIVES
To compare available nomograms in the literature defining trends in bilirubin levels across populations with different risk factor profiles and to study a mathematical bilirubin kinetics model describing the natural course of jaundice and the bilirubin rate of rise needed to cross percentile curves.
DATA SOURCES
We searched PubMed for publications between March 1999 and March 2009 that created transcutaneous nomograms. We performed the same search among abstracts presented in the past 2 years at meetings of the Pediatric Academic Societies or the European Society for Paediatric Research.
STUDY SELECTION
Inclusion criteria were gestational age of at least 35 weeks among study subjects, the use of an electronic transcutaneous bilirubinometer, and creation of a nomogram based on hour-specific bilirubin values. Four articles met the selection criteria.
DATA EXTRACTION
Jaundice risk factors were analyzed, and raw data were analyzed using nonlinear regression to describe trends in bilirubin levels and kinetics. The bilirubin exaggerated rate of rise needed to cross percentile curves was calculated.
DATA SYNTHESIS
Significant differences in bilirubin values exist across populations, and there is substantial variability in rates of rise. Hispanic neonates demonstrate higher rates of rise and later plateaus. Bilirubin rates of rise tend to plateau and become null (equilibrium between bilirubin production and elimination) at about 96 hours of life. Rates of rise needed to cross percentile curves decrease over time but are lower (approximately 0.11 mg/dL/h [to convert bilirubin level to micromoles per liter, multiply by 17.104]) in the first 48 hours of life than previously thought.
CONCLUSIONS
Transcutaneous bilirubin levels plateau and then decrease after about 96 hours of life in healthy neonates, with some differences across populations. A bilirubin rate of rise higher than in the previous period implies that bilirubin production exceeds elimination and indicates high risk for subsequent hyperbilirubinemia in neonates.
Topics: Bilirubin; Humans; Hyperbilirubinemia, Neonatal; Infant, Newborn; Nomograms; Racial Groups; Skin; Time Factors
PubMed: 19884597
DOI: 10.1001/archpediatrics.2009.187 -
Clinical Endocrinology May 2009Elevated circulating androgens are risk factors for several chronic, metabolic and reproductive disorders. Metformin is an insulin-sensitizing agent that may lower... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
Elevated circulating androgens are risk factors for several chronic, metabolic and reproductive disorders. Metformin is an insulin-sensitizing agent that may lower androgen levels. To evaluate the effects of metformin on endogenous androgens and SHBG levels in women, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing metformin with placebo or no treatment.
DATA SOURCE
We used OVID to search MEDLINE, EMBASE and CENTRAL until March 2007.
REVIEW METHODS
Two reviewers independently extracted data on methodological quality, participants, interventions and outcomes of interest. Our a priori primary outcome was post-treatment measurements. In a secondary analysis, we evaluated the difference between the pre- and post-treatment levels. We computed the weighted mean difference (WMD) as a measure of effect for each outcome using the DerSimonian-Laird random effects method. We used the I2 statistic to assess heterogeneity and explored its causes in subgroup analyses of features related to participants' characteristics and study design. Based on a regression model, we conducted sensitivity analyses by investigating the use of placebo as a predictor of effect size.
RESULTS
Twenty RCTs fulfilled the inclusion criteria. Pooled WMDs in post-treatment levels between the metformin and control group were -0.31 nmol/l (95% CI -0.65 to 0.03) for total testosterone (TT), 0.10 pmol/l (95% CI -0.89 to 1.10) for free testosterone (FT), 0.14 micromol/l (95% CI -0.34 to 0.62) for dehydroepiandrosteronesulfate (DHEAS), -0.60 nmol/l (95% CI -1.67 to 0.46) for androstenedione (AND) and 5.88 nmol/l (95% CI 2.01-9.75) for SHBG. Pooled WMDs of the pre- to post-treatment differences (i.e. with adjustment for baseline hormone levels) were -0.38 (95% CI -0.51 to -0.25) for TT, -2.71 (95% CI -10.35 to 4.93) for FT, -0.50 (95% CI -0.83 to -0.16) for DHEAS, -1.39 (95% CI -2.30 to -0.49) for AND and 6.63 (95% CI 2.32-10.94) for SHBG. In subgroup analyses, features related to the administered treatment (i.e. metformin as a single agent or as part of combined regimens) partly explained the heterogeneity. Sensitivity analyses of studies using placebo showed similar results to those not using placebo.
CONCLUSIONS
Our systematic review and meta-analysis provides evidence of metformin-induced changes in circulating androgens and SHBG levels in women but the quality of evidence is not high. However, there are no data from RCTs regarding these effects in postmenopausal women or healthy premenopausal women. High-quality RCTs are required to evaluate whether metformin has effects on surrogate markers and patient-important outcomes in these patient groups.
Topics: Androgens; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Insulin Resistance; Metformin; Obesity; Polycystic Ovary Syndrome; Randomized Controlled Trials as Topic; Risk Factors; Sex Hormone-Binding Globulin
PubMed: 19178532
DOI: 10.1111/j.1365-2265.2008.03459.x -
Current Opinion in Lipidology Feb 2009Hypothesis-generating systematic review of the impact of marine-derived omega-3 polyunsaturated fatty acids (PUFAs) on lipid, glycemic and hematological risk factors in... (Meta-Analysis)
Meta-Analysis
PURPOSE OF REVIEW
Hypothesis-generating systematic review of the impact of marine-derived omega-3 polyunsaturated fatty acids (PUFAs) on lipid, glycemic and hematological risk factors in type 2 diabetes using pooled data from randomized controlled trials searched up to 20 September 2008.
RECENT FINDINGS
Seven new trials in 2007 and 2008 were identified from 206 abstracts to give a total of 24 trials between 1966 and 2008 involving 1533 participants that could be pooled. The mean omega-3 PUFAs dose and duration of treatment in the new trials was 2.4 g/day and 24 weeks, respectively. Compared with placebo, omega-3 PUFAs supplementation decreased triglycerides by 7% (mean -0.17 mmol/l, 24 trials, 1530 participants), fibrinogen by 10% (mean -0.96 micromol/l, three trials, 159 participants), ADP platelet aggregation to ADP by 22% (mean -10.30%, two trials, 64 participants) and to collagen by 21% (mean -10.55%, two trials, 64 participants), with an LDL-cholesterol increase of 3% (mean 0.08 mmol/l, 21 trials, 1104 participants). None of the following risk factors appeared to be beneficially influenced: HDL-cholesterol, LDL particle size, glycemia, insulinemia, inflammatory biomarkers, blood pressure. However for some of these risk factors (such as inflammatory biomarkers) the number of trial patients was small Higher doses of omega-3 PUFAs (>or=2 g/day) may have greater triglyceride lowering effects.
SUMMARY
This systematic review and meta-analysis confirms the triglyceride lowering effects of omega-3 PUFAs, demonstrates potential dose-response effects and shows improvements in thrombogenesis. Omega-3 PUFAs raise LDL levels without concomitant changes in lipid particle size. Changes seen in conventional risk factors are insufficient to explain the cardiovascular disease risk reductions suggested to occur with omega-3 PUFAs.
Topics: Cardiovascular Diseases; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Dietary Supplements; Fatty Acids, Omega-3; Humans; Risk
PubMed: 19133409
DOI: 10.1097/mol.0b013e328321b3be -
Journal of Dairy Science Jan 2009Soils in many regions of the world have a low Se content. Consequently, forages and crops grown on these soils may provide inadequate dietary Se for humans and grazing... (Meta-Analysis)
Meta-Analysis Review
Soils in many regions of the world have a low Se content. Consequently, forages and crops grown on these soils may provide inadequate dietary Se for humans and grazing animals. Selenium supplementation has been used to enhance Se status and milk Se concentration, but results conflict. Milk Se concentration appears to be a useful indicator of animal and herd Se status, and reflects the responsiveness to supplementation. A systematic review and meta-analysis were carried out to summarize all available scientific evidence for the effect of oral Se supplementation on milk Se concentration in cattle. The literature search was based on electronic and nonelectronic databases. Fixed- and random-effects models of meta-analysis were used, and a meta-regression was carried out to evaluate heterogeneity among studies. Random-effects meta-analysis was performed on 42 studies published between 1977 and 2007. Oral Se supplementation resulted in an average increase in milk Se content of 0.16 (95% confidence interval: 0.117, 0.207) micromol/L, with a significant heterogeneity among studies. Weak publication bias was evident, but it did not change the average effect. The continent where the study was performed, Se source, Se dose, and the interaction between source and dose explained 71% of the between-study variance. On average, American cows supplemented with Se yeast (e.g., 6 mg/h per day) had greater milk Se concentrations (approximately 0.37 micromol/L) 75 d after the beginning of supplementation when compared with those supplemented with inorganic forms of Se. This information provides a basis for tailoring daily animal requirements and for enhancing the Se intake of consumers of dairy products.
Topics: Animals; Cattle; Dietary Supplements; Female; Milk; Publication Bias; Regression Analysis; Selenium
PubMed: 19109290
DOI: 10.3168/jds.2008-1545