Nonestrogen Therapies for Treatment of Genitourinary Syndrome of Menopause: A Systematic Review.

OBJECTIVE: To systematically review the literature and provide clinical practice guidelines regarding various nonestrogen therapies for treatment of genitourinary syndrome of menopause (GSM). DATA SOURCES: MEDLINE, EMBASE, ClinicalTrials.gov , and Cochrane databases were searched from inception to July 2021. We included comparative and noncomparative studies. Interventions and comparators were limited to seven products that are commercially available and currently in use (vaginal dehydroepiandrosterone [DHEA], ospemifene, laser or energy-based therapies, polycarbophil-based vaginal moisturizer, Tibolone, vaginal hyaluronic acid, testosterone). Topical estrogen, placebo, other nonestrogen products, as well as no treatment were considered as comparators. METHODS OF STUDY SELECTION: We double-screened 9,131 abstracts and identified 136 studies that met our criteria. Studies were assessed for quality and strength of evidence by the systematic review group. TABULATION, INTEGRATION, AND RESULTS: Information regarding the participants, details on the intervention and comparator and outcomes were extracted from the eligible studies. Alternative therapies were similar or superior to estrogen or placebo with minimal increase in adverse events. Dose response was noted with vaginal DHEA and testosterone. Vaginal DHEA, ospemifene, erbium and fractional carbon dioxide (CO 2 ) laser, polycarbophil-based vaginal moisturizer, tibolone, hyaluronic acid, and testosterone all improved subjective and objective signs of atrophy. Vaginal DHEA, ospemifene, tibolone, fractional CO 2 laser, polycarbophil-based vaginal moisturizer, and testosterone improved sexual function. CONCLUSION: Most nonestrogen therapies are effective treatments for the various symptoms of GSM. There are insufficient data to compare nonestrogen options to each other.

Vitamin D and Risk for Type 2 Diabetes in People With Prediabetes : A Systematic Review and Meta-analysis of Individual Participant Data From 3 Randomized Clinical Trials.

BACKGROUND: The role of vitamin D in people who are at risk for type 2 diabetes remains unclear. PURPOSE: To evaluate whether administration of vitamin D decreases risk for diabetes among people with prediabetes. DATA SOURCES: PubMed, Embase, and ClinicalTrials.gov from database inception through 9 December 2022. STUDY SELECTION: Eligible trials that were specifically designed and conducted to test the effects of oral vitamin D versus placebo on new-onset diabetes in adults with prediabetes. DATA EXTRACTION: The primary outcome was time to event for new-onset diabetes. Secondary outcomes were regression to normal glucose regulation and adverse events. Prespecified analyses (both unadjusted and adjusted for key baseline variables) were conducted according to the intention-to-treat principle. DATA SYNTHESIS: Three randomized trials were included, which tested cholecalciferol, 20 000 IU (500 mcg) weekly; cholecalciferol, 4000 IU (100 mcg) daily; or eldecalcitol, 0.75 mcg daily, versus matching placebos. Trials were at low risk of bias. Vitamin D reduced risk for diabetes by 15% (hazard ratio, 0.85 [95% CI, 0.75 to 0.96]) in adjusted analyses, with a 3-year absolute risk reduction of 3.3% (CI, 0.6% to 6.0%). The effect of vitamin D did not differ in prespecified subgroups. Among participants assigned to the vitamin D group who maintained an intratrial mean serum 25-hydroxyvitamin D level of at least 125 nmol/L (≥50 ng/mL) compared with 50 to 74 nmol/L (20 to 29 ng/mL) during follow-up, cholecalciferol reduced risk for diabetes by 76% (hazard ratio, 0.24 [CI, 0.16 to 0.36]), with a 3-year absolute risk reduction of 18.1% (CI, 11.7% to 24.6%). Vitamin D increased the likelihood of regression to normal glucose regulation by 30% (rate ratio, 1.30 [CI, 1.16 to 1.46]). There was no evidence of difference in the rate ratios for adverse events (kidney stones: 1.17 [CI, 0.69 to 1.99]; hypercalcemia: 2.34 [CI, 0.83 to 6.66]; hypercalciuria: 1.65 [CI, 0.83 to 3.28]; death: 0.85 [CI, 0.31 to 2.36]). LIMITATIONS: Studies of people with prediabetes do not apply to the general population. Trials may not have been powered for safety outcomes. CONCLUSION: In adults with prediabetes, vitamin D was effective in decreasing risk for diabetes. PRIMARY FUNDING SOURCE: None. (PROSPERO: CRD42020163522).

Pharmacologic and Nonpharmacologic Treatments for Urinary Incontinence in Women: A Systematic Review and Network Meta-analysis of Clinical Outcomes.

Background: Urinary incontinence (UI), a common malady in women, most often is classified as stress, urgency, or mixed. Purpose: To compare the effectiveness of pharmacologic and nonpharmacologic interventions to improve or cure stress, urgency, or mixed UI in nonpregnant women. Data Sources: MEDLINE, Cochrane Central Register of Controlled Trials (Wiley), Cochrane Database of Systematic Reviews (Wiley), EMBASE (Elsevier), CINAHL (EBSCO), and PsycINFO (American Psychological Association) from inception through 10 August 2018. Study Selection: 84 randomized trials that evaluated 14 categories of interventions and reported categorical cure or improvement outcomes. Data Extraction: 1 researcher extracted study characteristics, results, and study-level risk of bias, with verification by another independent researcher. The research team collaborated to assess strength of evidence (SoE) across studies. Data Synthesis: 84 studies reported cure or improvement outcomes (32 in stress UI, 16 in urgency UI, 4 in mixed UI, and 32 in any or unspecified UI type). The most commonly evaluated active intervention types included behavioral therapies, anticholinergics, and neuromodulation. Network meta-analysis showed that all interventions, except hormones and periurethral bulking agents (variable SoE), were more effective than no treatment in achieving at least 1 favorable UI outcome. Among treatments used specifically for stress UI, behavioral therapy was more effective than either α-agonists or hormones in achieving cure or improvement (moderate SoE); α-agonists were more effective than hormones in achieving improvement (moderate SoE); and neuromodulation was more effective than no treatment for cure, improvement, and satisfaction (high SoE). Among treatments used specifically for urgency UI, behavioral therapy was statistically significantly more effective than anticholinergics in achieving cure or improvement (high SoE), both neuromodulation and onabotulinum toxin A (BTX) were more effective than no treatment (high SoE), and BTX may have been more effective than neuromodulation in achieving cure (low SoE). Limitation: Scarce direct (head-to-head trial) evidence and population heterogeneity based on UI type, UI severity, and history of prior treatment. Conclusion: Most nonpharmacologic and pharmacologic interventions are more likely than no treatment to improve UI outcomes. Behavioral therapy, alone or in combination with other interventions, is generally more effective than pharmacologic therapies alone in treating both stress and urgency UI. Primary Funding Source: Patient-Centered Outcomes Research Institute. (PROSPERO: CRD42017069903).

Omega-3 Fatty Acids and Cardiovascular Disease: Summary of the 2016 Agency of Healthcare Research and Quality Evidence Review.

We summarize the 2016 update of the 2004 Agency of Healthcare Research and Quality's evidence review of omega-3 fatty acids and cardiovascular disease (CVD). The overall findings for the effects of marine oil supplements on intermediate CVD outcomes remain largely unchanged. There is high strength of evidence, based on numerous trials, of no significant effects of marine oils on systolic or diastolic blood pressures, but there are small, yet statistically significant increases in high density lipoprotein and low density lipoprotein cholesterol concentrations. The clinical significance of these small changes, particularly in combination, is unclear. The strongest effect of marine oils is on triglyceride concentrations. Across studies, this effect was dose-dependent and related to studies' mean baseline triglyceride concentration. In observational studies, there is low strength of evidence that increased marine oil intake lowers ischemic stroke risk. Among randomized controlled trials and observational studies, there is evidence of variable strength of no association with increased marine oil intake and lower CVD event risk. Evidence regarding alpha-linolenic acid intake is sparser. There is moderate strength of evidence of no effect on blood pressure or lipoprotein concentrations and low strength of evidence of no association with coronary heart disease, atrial fibrillation and congestive heart failure.

Omega-3 Fatty Acids and Cardiovascular Disease: An Updated Systematic Review.

BACKGROUND: The effect and association of omega-3 fatty acids (n-3 FA) intake and biomarker levels with cardiovascular (CV) clinical and intermediate outcomes remains controversial. We update prior Evidence Reports of n-3 FA and clinical and intermediate CV disease (CVD) outcomes. OBJECTIVES: Evaluate the effect of n-3 FA on clinical and selected intermediate CV outcomes and the association of n-3 FA intake and biomarkers with CV outcomes. The n-3 FA under review include eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), stearidonic acid (SDA), and alphalinolenic acid (ALA). DATA SOURCES: MEDLINE®, Embase®, the Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and CAB Abstracts from 2000 or 2002 to June 8, 2015, and eligible studies from the original reports and relevant existing systematic reviews. REVIEW METHODS: We included randomized controlled trials (RCTs) of any n-3 FA intake compared to no, lower, or other n-3 FA intake with an outcome of interest conducted in healthy adults, those at risk for CVD, or those with CVD. We also included prospective observational studies of the association between baseline n-3 FA intake or biomarker level and followup outcomes. We required 1 year or more of followup for clinical outcomes and 4 weeks for intermediate outcomes (blood pressure [BP] and lipids). RESULTS: From 11,440 citations (from electronic literature searches and existing systematic reviews), 829 abstracts met basic eligibility criteria; 61 RCTs and 37 longitudinal observational studies (in 147 articles) were included. Most RCTs and observational studies had few risk-of-bias concerns.Total n-3 FA: There is low strength of evidence (SoE) of no association between total n-3 FA intake and stroke death or myocardial infarction. There is insufficient evidence for other outcomes.Marine oils, total: There is moderate to high SoE that higher marine oil intake lowers triglycerides (Tg), raises high density lipoprotein cholesterol (HDL-c), and lowers the ratio of total cholesterol to HDL-c but raises low density lipoprotein cholesterol (LDL-c); also that higher marine oil intake does not affect major adverse CV events, all-cause death, total stroke, sudden cardiac death, coronary revascularization, atrial fibrillation, or BP. There is low SoE of associations between higher marine oil intake and decreased risk of CVD death, coronary heart disease (CHD), myocardial infarction, ischemic stroke, and congestive heart failure (CHF). There is low SoE of no association with CHD death or hemorrhagic stroke. There is insufficient evidence for other outcomes.Marine oil FA individually: There is low SoE of no associations between EPA or DHA intake (separately) and CHD, and between EPA or DPA and atrial fibrillation. There is low SoE of no association between EPA biomarkers and atrial fibrillation, but moderate SoE of no effect of purified DHA supplementation on BP or LDL-c. There is insufficient evidence for other specific marine oil FA and outcomes.ALA: There is moderate SoE of no effect of ALA intake on BP, LDL-c, HDL-c, or Tg. There is low SoE of no association between ALA intake or biomarker level and CHD, CHD death, atrial fibrillation, and CHF. There is insufficient evidence for other outcomes.Other n-3 FA analyses: There is insufficient evidence comparing n-3 FA with each other or for SDA.Subgroup analyses: Nineteen of 22 studies found no interaction of sex on any effect of n-3 FA. Likewise, 19 of 20 studies found no differential effect by statin co-use. Within 16 studies evaluating diabetes subgroups, 2 found statistically significant beneficial effects of n-3 FA in those with diabetes but not in those without diabetes, but no test of interaction was reported. CONCLUSIONS: The 61 RCTs mostly compared marine oil supplements with placebo on CVD outcomes in populations at risk for CVD or with CVD, while the 37 observational studies mostly examined associations between various individual n-3 FA and long-term CVD events in generally healthy populations. Compared with the prior report on n-3 FA and CVD, there is more robust RCT evidence on ALA and on clinical CV outcomes; also, by design there are newly added data on associations between n-3 FA biomarkers and CV outcomes. However, conclusions regarding the effect of n-3 FA intake on CV outcomes or associations with outcomes remain substantially unchanged. Marine oils statistically significantly raise HDL-c and LDL-c by similar amounts (≤2 mg/dL), while lowering Tg in a dose-dependent manner, particularly in individuals with elevated Tg; they have no significant effect on BP. ALA has no significant effect on intermediate outcomes. Limited data were available from RCTs on the effect of n-3 FA on clinical CVD outcomes. Observational studies suggest that higher marine oil intake (including from dietary fish) is associated with lower risk of several CVD outcomes. No clear differences in effects or associations were evident based on population, demographic features, or cointerventions. Future RCTs would be needed to establish adequate evidence of the effect of n-3 FA on CVD outcomes or to clarify differential effects in different groups of people. However, future trials are unlikely to alter conclusions about the effects of n-3 FA supplementation on intermediate cardiovascular outcomes (BP, LDL-c, HDL-c, or Tg).

Risk stratification for arrhythmic events in patients with asymptomatic pre-excitation: A systematic review for the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

OBJECTIVE: To review the literature systematically to determine whether noninvasive or invasive risk stratification, such as with an electrophysiological study of patients with asymptomatic pre-excitation, reduces the risk of arrhythmic events and improves patient outcomes. METHODS: PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (all January 1, 1970, through August 31, 2014) were searched for randomized controlled trials and cohort studies examining noninvasive or invasive risk stratification in patients with asymptomatic pre-excitation. Studies were rejected for low-quality design or the lack of an outcome, population, intervention, or comparator of interest or if they were written in a language other than English. RESULTS: Of 778 citations found, 9 studies met all the eligibility criteria and were included in this paper. Of the 9 studies, 1 had a dual design-a randomized controlled trial of ablation versus no ablation in 76 patients and an uncontrolled prospective cohort of 148 additional patients-and 8 were uncontrolled prospective cohort studies (n=1,594). In studies reporting a mean age, the range was 32 to 50 years, and in studies reporting a median age, the range was 19 to 36 years. The majority of patients were male (range, 50% to 74%), and <10% had structural heart disease. In the randomized controlled trial component of the dual-design study, the 5-year Kaplan-Meier estimates of the incidence of arrhythmic events were 7% among patients who underwent ablation and 77% among patients who did not undergo ablation (relative risk reduction: 0.08; 95% confidence interval: 0.02 to 0.33; p<0.001). In the observational cohorts of asymptomatic patients who did not undergo catheter ablation (n=883, with follow-up ranging from 8 to 96 months), regular supraventricular tachycardia or benign atrial fibrillation (shortest RR interval >250 ms) developed in 0% to 16%, malignant atrial fibrillation (shortest RR interval ≤250 ms) in 0% to 9%, and ventricular fibrillation in 0% to 2%, most of whom were children in the last case. CONCLUSIONS: The existing evidence suggests risk stratification with an electrophysiological study of patients with asymptomatic pre-excitation may be beneficial, along with consideration of accessory-pathway ablation in those deemed to be at high risk of future arrhythmias. Given the limitations of the existing data, well-designed and well-conducted studies are needed.

Leukotriene-receptor antagonists versus placebo in the treatment of asthma in adults and adolescents: a systematic review and meta-analysis.

BACKGROUND: Leukotriene-receptor antagonists (LTRAs) are recommended as an alternative treatment in patients with mild asthma, but their effect compared with placebo is unclear. PURPOSE: To determine the benefits and harms of LTRAs as monotherapy or in combination with inhaled corticosteroids compared with placebo in adults and adolescents with asthma. DATA SOURCES: MEDLINE and the Cochrane Central Register of Controlled Trials from inception through June 2015. STUDY SELECTION: Peer-reviewed, English-language, randomized, controlled trials in patients with asthma that reported the effect of LTRAs versus placebo on measures of asthma control. DATA EXTRACTION: Three researchers extracted data on study population, interventions, outcome measures, and adverse events. One researcher assessed risk of bias. DATA SYNTHESIS: Of the 2008 abstracts that were screened, 50 trials met eligibility criteria. Random-effects meta-analyses of 6 trials of LTRA monotherapy showed that LTRAs reduced the risk for an exacerbation (summary risk ratio [RR], 0.60 [95% CI, 0.44 to 0.81]). In 4 trials of LTRAs as add-on therapy to inhaled corticosteroids, the summary RR for exacerbation was 0.80 (CI, 0.60 to 1.07). Leukotriene-receptor antagonists either as monotherapy or as add-on therapy to inhaled corticosteroids increased FEV1, whereas FEV1 percentage of predicted values was improved only in trials of LTRA monotherapy. Adverse event rates were similar in the intervention and comparator groups. LIMITATION: Variation in definitions and reporting of outcomes, high risk of bias in some studies, heterogeneity of findings, possible selective outcome reporting bias, and inability to assess the effect of asthma severity on summary estimates. CONCLUSION: Leukotriene-receptor antagonists as monotherapy improved asthma control compared with placebo, but which patients are most likely to respond to treatment with LTRAs remains unclear. PRIMARY FUNDING SOURCE: National Institutes of Health.

Vitamin D and Calcium: A Systematic Review of Health Outcomes (Update).

BACKGROUND: In 2009, the Institute of Medicine/Food and Nutrition Board constituted a Dietary Reference Intakes (DRI) committee to undertake a review of the evidence that had emerged (since the 1997 DRI report) on the relationship of vitamin D and calcium, both individually and combined, to a wide range of health outcomes, and potential revision of the DRI values for these nutrients. To support that review, several United States and Canadian Federal Government agencies commissioned a systematic review of the scientific literature for use during the deliberations by the committee. The intent was to support a transparent literature review process and provide a foundation for subsequent reviews of the nutrients. The committee used the resulting literature review in their revision of the DRIs.In 2013, in preparation for a project the National Institutes of Health Office of Dietary Supplements (NIH/ODS) was undertaking related to evidence-based decisionmaking for vitamin D in primary care, based on the updated DRI report, the ODS and AHRQ requested an update to the 2009 systematic review to incorporate the findings of studies conducted since the 2009 evidence review on the relationship between vitamin D alone or vitamin D plus calcium to selected health outcomes and to report on the methods used to assay vitamin D in the included trials. PURPOSE: To systematically summarize the evidence on the relationship between vitamin D alone or in combination with calcium on selected health outcomes included in the earlier review: primarily those related to bone health, cardiovascular health, cancer, immune function, pregnancy, all-cause mortality, and vitamin D status; and to identify the vitamin D assay methods and procedures used for the interventional studies that aimed to assess the effect of vitamin D administration on serum 25(OH)D concentrations, and to stratify key outcomes by methods used to assay serum 25(OH)D concentrations. DATA SOURCES: MEDLINE; Cochrane Central; Cochrane Database of Systematic Reviews; and the Health Technology Assessments; search limited to English-language articles on humans. STUDY SELECTION: Primary interventional or prospective observational studies that reported outcomes of interest in human subjects in relation to vitamin D alone or in combination with calcium, as well as systematic reviews that met the inclusion and exclusion criteria. DATA EXTRACTION: A standardized protocol with predefined criteria was used to extract details on study design, interventions, outcomes, and study quality. DATA SYNTHESIS: We summarized 154 newly identified primary articles and two new systematic reviews that incorporated more than 93 additional primary articles. Available evidence focused mainly on bone health, cardiovascular diseases, or cancer outcomes. Findings were inconsistent across studies for bone health; breast, colorectal, and prostate cancer; cardiovascular disease and mortality; immune function; and pregnancy-related outcomes. Few studies assessed pancreatic cancer and birth outcomes. One new systematic review of observational studies found that circulating 25(OH)D was generally inversely associated with risk for cardiovascular disease. Methods used to assay serum 25(OH)D in studies reporting on key outcomes diverged widely. The current report also identified one new systematic review published since the original report that addressed whether a dose response relationship exists between dietary and supplemental vitamin D intake and serum 25(OH)D concentrations. The systematic review, based on 76 RCTs, reported widely varying increases in serum concentrations of 25(OH)D for similar doses of vitamin D, with a general increase in serum concentration with dietary intake. The RCTs identified for the current report found increases in serum 25(OH)D with supplementation; however, the findings varied by age group and health status of participants, baseline vitamin D status, dose, duration, and assay used to assess serum 25(OH)D. LIMITATIONS: Studies on vitamin D and calcium were not specifically targeted at life stages (except for pregnant and postmenopausal women) specified for the determination of DRI and were often underpowered for their intended outcomes. Studies vary widely in methodological quality and in the assays used to measure vitamin D status. CONCLUSIONS: In solid agreement with the findings of the original report, the majority of the findings concerning vitamin D, alone or in combination with calcium, on the health outcomes of interest were inconsistent. Associations observed in prospective cohort and nested case-control studies were inconsistent, or when consistent, were rarely supported by the results of randomized controlled trials. Clear dose-response relationships between intakes of vitamin D and health outcomes were rarely observed. Although a large number of new studies (and longer followups to older studies) were identified, particularly for cardiovascular outcomes, all-cause mortality, several types of cancer, and intermediate outcomes for bone health, no firm conclusions can be drawn. Studies identified for the current report suggest a possible U-shaped association between serum 25(OH)D concentrations and both all-cause mortality and hypertension and also suggest that the level of supplemental vitamin D and calcium administered in the Women's Health Initiative Calcium-Vitamin D Trial are not associated with an increased risk for cardiovascular disease or cancer among postmenopausal women who are not taking additional supplemental vitamin D and calcium. Studies suggest the method used to assay 25(OH)D may influence the outcomes of dose-response assessments. Beyond these observations, it is difficult to make any substantive statements on the basis of the available evidence concerning the association of either serum 25(OH)D concentration, vitamin D supplementation, calcium intake, or the combination of both nutrients, with the various health outcomes because most of the findings were inconsistent.

Systematic review: Vitamin D and cardiometabolic outcomes.

BACKGROUND: Vitamin D may modify risk for cardiometabolic outcomes (type 2 diabetes, hypertension, or cardiovascular disease). PURPOSE: To examine the association between vitamin D status, including the effect of vitamin D supplementation, and cardiometabolic outcomes in generally healthy adults. DATA SOURCES: English-language studies in MEDLINE (inception to 4 November 2009) and the Cochrane Central Register of Controlled Trials (fourth quarter of 2009). STUDY SELECTION: 11 reviewers screened citations to identify longitudinal cohort studies that reported associations between vitamin D status and cardiometabolic outcomes, including randomized trials of vitamin D supplementation. DATA EXTRACTION: 5 independent reviewers extracted data about study conduct, participant characteristics, outcomes, and quality. Differences were resolved by consensus. DATA SYNTHESIS: 13 observational studies (14 cohorts) and 18 trials were eligible. Three of 6 analyses (from 4 different cohorts) reported a lower incident diabetes risk in the highest versus the lowest vitamin D status groups. Eight trials found no effect of vitamin D supplementation on glycemia or incident diabetes. In meta-analysis of 3 cohorts, lower 25-hydroxyvitamin D concentration was associated with incident hypertension (relative risk, 1.8 [95% CI, 1.3 to 2.4]). In meta-analyses of 10 trials, supplementation nonsignificantly reduced systolic blood pressure (weighted mean difference, -1.9 mm Hg [CI, -4.2 to 0.4 mm Hg]) and did not affect diastolic blood pressure (weighted mean difference, -0.1 mm Hg [CI, -0.7 to 0.5 mm Hg]). Lower 25-hydroxyvitamin D concentration was associated with incident cardiovascular disease in 5 of 7 analyses (6 cohorts). Four trials found no effect of supplementation on cardiovascular outcomes. LIMITATIONS: Studies included primarily white participants. Observational studies were heterogeneous. Several trials reported post hoc analyses. CONCLUSION: The association between vitamin D status and cardiometabolic outcomes is uncertain. Trials showed no clinically significant effect of vitamin D supplementation at the dosages given. PRIMARY FUNDING SOURCE: National Institute of Diabetes and Digestive and Kidney Disease, the National Institutes of Health Office of Dietary Supplements, U.S. Food and Drug Administration, Agency for Healthcare Research and Quality, and Public Health Agency of Canada.

Vitamin D and calcium: a systematic review of health outcomes.

BACKGROUND: Since the 1997 Dietary Reference Intake (DRI) values for vitamin D and calcium were established new data have become available on their relationship, both individually and combined, to a wide range of health outcomes. The Institute of Medicine/Food and Nutrition Board has constituted a DRI committee to undertake a review of the evidence and potential revision of the current DRI values for these nutrients. To support this review, several US and Canadian federal government agencies commissioned a systematic review of the scientific literature for use during the deliberations by the committee. The intent of providing a systematic review to the committee is to support transparency of the literature review process and provide a foundation for subsequent reviews of the nutrients. PURPOSE: To systematically summarize the evidence on the relationship between vitamin D, calcium, and a combination of both nutrients on a wide range of health outcomes as identified by the IOM, AHRQ and technical expert panel convened to support the project. DATA SOURCES: MEDLINE; Cochrane Central; Cochrane Database of Systematic Reviews; and the Health Technology Assessments; search limited to English-language articles in humans. STUDY SELECTION: Primary interventional or observational studies that reported outcomes of interest in human subjects in relation to vitamin D and/or calcium, as well as systematic reviews that met the inclusion and exclusion criteria. Cross sectional and retrospective case-control studies were excluded. DATA EXTRACTION: A standardized protocol with predefined criteria was used to extract details on study design, interventions, outcomes, and study quality. DATA SYNTHESIS: We summarized 165 primary articles and 11 systematic reviews that incorporated over 200 additional primary articles. Available evidence focused mainly on bone health, cardiovascular diseases or cancer outcomes. For many outcomes, it was difficult to draw firm conclusions on the basis of the available literature concerning the association of either serum 25(OH)D concentration or calcium intake, or the combination of both nutrients. Findings were inconsistent across studies for colorectal and prostate cancer, and pregnancy-related outcomes including preeclampsia. There were few studies for pancreatic cancer and immune function. Among trials of hypertensive adults, calcium supplementation lowered systolic, but not diastolic, blood pressure by 2-4 mm Hg. For body weight, the trials were consistent in finding no significant effect of increased calcium intake on weight. For growth rates, a meta-analysis did not find a significant effect on weight or height gain attributable to calcium supplement in children. For bone health, one systematic review found that vitamin D plus calcium supplementation resulted in small increases in BMD of the spine and other areas in postmenopausal women. For breast cancer, calcium intakes in premenopausal women were associated with a decreased risk. For prostate cancer, some studies reported that high calcium intakes were associated with an increased risk. LIMITATIONS: Studies on vitamin D and calcium were not specifically targeted at life stages (except for pregnant and postmenopausal women) specified for the determination of DRI. There is large variation on the methodological quality of studies examined. Use of existing systematic reviews limits analyses that could be performed on this source of information. CONCLUSIONS: The majority of the findings concerning vitamin D, calcium, or a combination of both nutrients on the different health outcomes were inconsistent. Synthesizing a dose-response relation between intake of either vitamin D, calcium, or both nutrients and health outcomes in this heterogeneous body of literature proved challenging.

Heterogeneity and lack of good quality studies limit association between folate, vitamins B-6 and B-12, and cognitive function.

We conducted a systematic review to evaluate the association between folate, vitamin B-6, vitamin B-12, and cognitive function in the elderly. Our search was conducted in Medline for English-language publications of human subjects from 1966 through November 2006; we supplemented these results with information from article reviews and domain experts. We included longitudinal cohort and case-control studies of B vitamins and analyses of cognitive tests or Alzheimer's disease. We evaluated the quality and heterogeneity of study outcomes and assessed 30 different cognitive function tests. Of 24 studies that met eligibility criteria, 16 were determined to be of fair quality. A majority of the studies reviewed 2 or more B vitamins. Considerable heterogeneity was found among B-vitamin-level thresholds, comparisons, and data analyses. Six of 10 folate studies reported a significant association between low baseline blood folate concentrations and subsequent poor test performance in the global cognitive domain, and 4 of 9 folate studies found associations between low blood folate concentrations and increased prevalence of Alzheimer's disease. Studies did not reveal an association of vitamin B-6 and vitamin B-12 blood concentrations with cognitive-test performance or Alzheimer's disease, nor was B-vitamin dietary intake associated with cognitive function. Higher plasma homocysteine concentrations were associated with poorer cognitive function. Although the majority of studies indicated that low blood folate concentrations predicted poorer cognitive function, data supporting this association were limited because of the heterogeneity in cognition-assessment methodology, and scarcity of good quality studies and standardized threshold levels for categorizing low B-vitamin status.

A collaborative effort to apply the evidence-based review process to the field of nutrition: challenges, benefits, and lessons learned.

Evidence-based systematic reviews evaluating dietary intake and nutritional interventions are becoming common but are relatively few compared with other applications. Concerns remain that systematic reviews of nutrition topics pose several unique challenges. We present a successful collaboration to systematically review the health effects of a common nutrient, n-3 (or omega-3) fatty acids, across a wide range of clinical conditions. More generally, we discuss the challenges faced and the lessons learned during the review, the benefits of systematic review of nutritional topics, and recommendations for conducting and reviewing nutrition-related studies. Through a structured but flexible process, 3 Evidence-based Practice Centers in the Agency for Healthcare Research and Quality program produced 11 reports on a wide range of n-3 fatty acid-related topics. An important resource has been created, through which nutrition and dietetics researchers, clinical dietitians and nutritionists, clinicians, and the general public can understand the state of the science. The process identified challenges and problems in evaluating the health effects of n-3 fatty acid consumption, highlighted challenges to reviewing the human nutrition literature, and yielded recommendations for future research. The goals of these systematic reviews, the processes that were used, the benefits and limitations of the collaboration, and the conclusions of the reviews, including recommendations for future research, are summarized here.

Effect of chromium supplementation on glucose metabolism and lipids: a systematic review of randomized controlled trials.

OBJECTIVE: A systematic review of the effect of chromium supplementation on glucose metabolism and lipid levels. RESEARCH DESIGN AND METHODS: A literature search was conducted in MEDLINE and the Commonwealth Agricultural Bureau. Eligible studies were English language randomized controlled trials of chromium supplement intake > or = 3 weeks, with > or = 10 participants receiving chromium. All trials with glucose metabolism outcomes and trials of individuals with diabetes or glucose intolerance for lipid outcomes were included. Meta-analyses were performed as appropriate. RESULTS: Forty-one studies met criteria, almost half of which were of poor quality. Among participants with type 2 diabetes, chromium supplementation improved glycosylated hemoglobin levels by -0.6% (95% CI -0.9 to -0.2) and fasting glucose by -1.0 mmol/l (-1.4 to -0.5) but not lipids. There was no benefit in individuals without diabetes. There were some indications of dose effect and differences among chromium formulations. Larger effects were more commonly observed in poor-quality studies. The evidence was limited by poor study quality, heterogeneity in methodology and results, and a lack of consensus on assessment of chromium status. CONCLUSIONS: No significant effect of chromium on lipid or glucose metabolism was found in people without diabetes. Chromium supplementation significantly improved glycemia among patients with diabetes. However, future studies that address the limitations in the current evidence are needed before definitive claims can be made about the effect of chromium supplementation.

Vitamin B6, B12, and folic acid supplementation and cognitive function: a systematic review of randomized trials.

BACKGROUND: Despite their important role in cognitive function, the value of B vitamin supplementation is unknown. A systematic review of the effect of pyridoxine hydrochloride (hereinafter "vitamin B(6)"), cyanocobalamin or hydroxycobalamin (hereinafter "vitamin B(12)"), and folic acid supplementation on cognitive function was performed. METHODS: Literature search conducted in MEDLINE with supplemental articles from reviews and domain experts. We included English language randomized controlled trials of vitamins B(6) and/or B(12) and/or folic acid supplementation with cognitive function outcomes. RESULTS: Fourteen trials met our criteria; most were of low quality and limited applicability. Approximately 50 different cognitive function tests were assessed. Three trials of vitamin B(6) and 6 of vitamin B(12) found no effect overall in a variety of doses, routes of administration, and populations. One of 3 trials of folic acid found a benefit in cognitive function in people with cognitive impairment and low baseline serum folate levels. Six trials of combinations of the B vitamins all concluded that the interventions had no effect on cognitive function. Among 3 trials, those in the placebo arm had greater improvements in a small number of cognitive tests than participants receiving either folic acid or combination B-vitamin supplements. The evidence was limited by a sparsity of studies, small sample size, heterogeneity in outcomes, and a lack of studies that evaluated symptoms or clinical outcomes. CONCLUSION: The evidence does not yet provide adequate evidence of an effect of vitamin B(6) or B(12) or folic acid supplementation, alone or in combination, on cognitive function testing in people with either normal or impaired cognitive function.

n-3 Fatty acids from fish or fish-oil supplements, but not alpha-linolenic acid, benefit cardiovascular disease outcomes in primary- and secondary-prevention studies: a systematic review.

Studies on the relation between dietary n-3 fatty acids (FAs) and cardiovascular disease vary in quality, and the results are inconsistent. A systematic review of the literature on the effects of n-3 FAs (consumed as fish or fish oils rich in eicosapentaenoic acid and docosahexaenoic acid or as alpha-linolenic acid) on cardiovascular disease outcomes and adverse events was conducted. Studies from MEDLINE and other sources that were of > or =1 y in duration and that reported estimates of fish or n-3 FA intakes and cardiovascular disease outcomes were included. Secondary prevention was addressed in 14 randomized controlled trials (RCTs) of fish-oil supplements or of diets high in n-3 FAs and in 1 prospective cohort study. Most trials reported that fish oil significantly reduced all-cause mortality, myocardial infarction, cardiac and sudden death, or stroke. Primary prevention of cardiovascular disease was reported in 1 RCT, in 25 prospective cohort studies, and in 7 case-control studies. No significant effect on overall deaths was reported in 3 RCTs that evaluated the effects of fish oil in patients with implantable cardioverter defibrillators. Most cohort studies reported that fish consumption was associated with lower rates of all-cause mortality and adverse cardiac outcomes. The effects on stroke were inconsistent. Evidence suggests that increased consumption of n-3 FAs from fish or fish-oil supplements, but not of alpha-linolenic acid, reduces the rates of all-cause mortality, cardiac and sudden death, and possibly stroke. The evidence for the benefits of fish oil is stronger in secondary- than in primary-prevention settings. Adverse effects appear to be minor.

A systematic review of the effect of the Excebrane dialyser on biomarkers of lipid peroxidation.

BACKGROUND: Oxidative stress is prevalent in dialysis patients and has been implicated in the pathogenesis of cardiovascular disease and anaemia. We conducted a systematic review and meta-analysis to examine the effect of Excebrane, a vitamin E-coated cellulose-based dialyser, on circulating biomarkers of lipid peroxidation, as surrogate markers of oxidative stress. METHODS: The primary sources used to identify candidate studies included PubMed, the Cochrane Central Register of Controlled Trials, a bibliography provided by the dialyser manufacturer, and a manual search of abstracts from proceedings of scientific meetings and review articles. Studies were selected for analysis if their design included a comparator group (primarily within patient comparison, i.e. pre- and post-study evaluations). For the meta-analysis, we computed the overall change of the outcome from baseline using a random-effects model. A supplemental analysis was performed in which the absolute levels of these biomarkers of lipid peroxidation were converted to a common unit by calculating standardized effect sizes. RESULTS: Fourteen peer-reviewed articles met the criteria. The studies consisted of 11 single arm, one randomized crossover and two randomized controlled trials, with a total of 37 to 158 evaluable patients, according to the outcome of interest analysed. Due to the paucity of randomized trials, the meta-analysis was limited to the Excebrane arm of each study. When the studies were combined according to similar measurement units, the overall mean decrease in malondialdehyde (MDA) level was -0.3 mM (95% CI, -0.5 to -0.1 mM; seven studies) and -0.8 nmol/mg low-density lipoprotein (LDL) (95% CI, -1.3 to -0.4 nmol/mg LDL; three studies), respectively. The summary estimate revealed a non-significant decrease in pre-dialysis thiobarbituric acid reactive substances (TBARS) level of 0.4 microM (95% CI, -1.2 to 0.4 microM; three studies). When the MDA and TBARS studies were combined using the standardized effect size, the mean decrease in these biomarkers of lipid peroxidation was statistically significant at -1.7 units (95% CI, -2.7, -0.7 units; 13 studies). A meta-analysis on the effect of Excebrane on pre-dialysis levels of oxidized-LDL could not be performed due to study heterogeneity. CONCLUSION: The conversion of dialysis patients to a vitamin E-coated dialyser is associated with an improvement in circulating biomarkers of lipid peroxidation, which is of potential clinical benefit.

Effects of omega-3 fatty acids on serum markers of cardiovascular disease risk: a systematic review.

Greater fish oil consumption has been associated with reduced CVD risk, although the mechanisms are unclear. Plant-source oil omega-3 fatty acids (ALA) have also been studied regarding their cardiovascular effect. We conducted a systematic review of randomized controlled trials that evaluated the effect of consumption of fish oil and ALA on commonly measured serum CVD risk factors, performing meta-analyses when appropriate. Combining 21 trials evaluating lipid outcomes, fish oil consumption resulted in a summary net change in triglycerides of -27 (95% CI -33, -20)mg/dL, in HDL cholesterol of +1.6 (95% CI +0.8, +2.3)mg/dL, and in LDL cholesterol of +6 (95% CI +3, +8)mg/dL. There was no effect of fish oil on total cholesterol. Across studies, higher fish oil dose and higher baseline levels were associated with greater reductions in serum triglycerides. Overall, the 27 fish oil trials evaluating Hgb A(1c) or FBS found small non-significant net increases compared to control oils. Five studies of ALA were inconsistent in their effects on lipids, Hgb A(1c) or FBS. Four studies investigating the effects of omega-3 fatty acids on hs-CRP were also inconsistent and non-significant. The evidence supports a dose-dependent beneficial effect of fish oil on serum triglycerides, particularly among people with more elevated levels. Fish oil consumption also modestly improves HDL cholesterol, increases LDL cholesterol levels, but does not appear to adversely affect glucose homeostasis. The evidence regarding the effects of omega-3 fatty acids on hs-CRP is inconclusive, as are data on ALA.

Effects of omega-3 fatty acids on coronary restenosis, intima-media thickness, and exercise tolerance: a systematic review.

Greater omega-3 fatty acid consumption is associated with reduced cardiovascular disease risk. Though the mechanisms of their effect are unclear, they may involve lesion formation and heart function. We conducted a systematic review of the clinical literature on the effect of omega-3 fatty acids on measures of vascular structure and function. We included studies that assessed fish and plant sources of omega-3 fatty acids on coronary artery restenosis after angioplasty, carotid IMT, and exercise capacity. Compared to placebo, the summary risk ratio of coronary artery restenosis with fish oil is 0.87 (95% CI 0.73, 1.05) across 12 randomized controlled trials. Two prospective studies reported increased carotid IMT, whereas two cross-sectional studies reported a reduction of IMT, with fish, fish oil or ALA consumption. Three randomized trials and three uncontrolled studies reported small non-significant improvements in exercise capacity with fish oil. Overall, little or no effect of fish oil was found for a variety of markers of cardiovascular disease risk. There are insufficient studies to draw conclusions about the effect of ALA. The dearth of long term data on fish consumption or omega-3 fatty acid supplementation on measures of cardiovascular disease risk severely limits our ability to draw definitive conclusions at this time.