Comparative effects of vitamin and mineral supplements in the management of type 2 diabetes in primary care: A systematic review and network meta-analysis of randomized controlled trials.

Medical nutrition treatment can manage diabetes and slow or prevent its complications. The comparative effects of micronutrient supplements, however, have not yet been well established. We aimed at evaluating the comparative effects of vitamin and mineral supplements on managing glycemic control and lipid metabolism for type 2 diabetes mellitus (T2DM) to inform clinical practice. Electronic and hand searches for randomized controlled trials (RCTs) were performed until June 1, 2022. We selected RCTs enrolling patients with T2DM who were treated with vitamin supplements, mineral supplements, or placebo/no treatment. Data were pooled via frequentist random-effects network meta-analyses. A total of 170 eligible trials and 14223 participants were included. Low to very low certainty evidence established chromium supplements as the most effective in reducing fasting blood glucose levels and homeostasis model assessment of insulin resistance (SUCRAs: 90.4% and 78.3%, respectively). Vitamin K supplements ranked best in reducing glycated hemoglobin A1c and fasting insulin levels (SUCRAs: 97.0% and 82.3%, respectively), with moderate to very low certainty evidence. Vanadium supplements ranked best in lowering total cholesterol levels with very low evidence certainty (SUCRAs:100%). Niacin supplements ranked best in triglyceride reductions and increasing high-density lipoprotein cholesterol levels with low to very low evidence certainty (SUCRAs:93.7% and 94.6%, respectively). Vitamin E supplements ranked best in reducing low-density lipoprotein cholesterol levels with very low evidence certainty (SUCRAs:80.0%). Our analyses indicated that micronutrient supplements, especially chromium, vitamin E, vitamin K, vanadium, and niacin supplements, may be more efficacious in managing T2DM than other micronutrients. Considering the clinical importance of these findings, new research is needed to get better insight into this issue.

Effect of vitamin B supplementation on cancer incidence, death due to cancer, and total mortality: A PRISMA-compliant cumulative meta-analysis of randomized controlled trials.

BACKGROUND: Observational studies have suggested that vitamin B supplementation is associated with cancer risk, but this association remains controversial. A pooled data-based meta-analysis was conducted to summarize the evidence from randomized controlled trials (RCTs) investigating the effects of vitamin B supplementation on cancer incidence, death due to cancer, and total mortality. METHODS: PubMed, EmBase, and the Cochrane Library databases were searched to identify trials to fit our analysis through August 2015. Relative risk (RR) was used to measure the effect of vitamin B supplementation on the risk of cancer incidence, death due to cancer, and total mortality using a random-effect model. Cumulative meta-analysis, sensitivity analysis, subgroup analysis, heterogeneity tests, and tests for publication bias were also conducted. RESULTS: Eighteen RCTs reporting the data on 74,498 individuals were included in the meta-analysis. Sixteen of these trials included 4103 cases of cancer; in 6 trials, 731 cancer-related deaths occurred; and in 15 trials, 7046 deaths occurred. Vitamin B supplementation had little or no effect on the incidence of cancer (RR: 1.04; 95% confidence interval [CI]: 0.98-1.10; P = 0.216), death due to cancer (RR, 1.05; 95% CI: 0.90-1.22; P = 0.521), and total mortality (RR, 1.00; 95% CI: 0.94-1.06; P = 0.952). Upon performing a cumulative meta-analysis for cancer incidence, death due to cancer, and total mortality, the nonsignificance of the effect of vitamin B persisted. With respect to specific types of cancer, vitamin B supplementation significantly reduced the risk of skin melanoma (RR, 0.47; 95% CI: 0.23-0.94; P = 0.032). CONCLUSION: Vitamin B supplementation does not have an effect on cancer incidence, death due to cancer, or total mortality. It is associated with a lower risk of skin melanoma, but has no effect on other cancers.

Flexible Electronics: An Epidermal Stimulation and Sensing Platform for Sensorimotor Prosthetic Control, Management of Lower Back Exertion, and Electrical Muscle Activation (Adv. Mater. 22/2016).

The design of an ultrathin, conformal electronic device that integrates electrotactile stimulation with electromyography, temperature, and strain sensing in a single, simple platform is reported by J. A. Rogers and co-workers on page 4462. Demonstrated application possibilities include prosthetic control with sensory feedback, monitors, and stimulation signals related to lower back exertion, and electrical muscle stimulation with feedback control.

An Epidermal Stimulation and Sensing Platform for Sensorimotor Prosthetic Control, Management of Lower Back Exertion, and Electrical Muscle Activation.

The design of an ultrathin, conformal electronic device that integrates electrotactile stimulation with electromyography, temperature, and strain sensing in a single, simple platform is reported. Experiments demonstrate simultaneous use of multiple modes of operation of this type of device in the sensorimotor control of robotic systems, in the monitoring of lower back exertion and in muscle stimulation.

Tea consumption and risk of cardiovascular outcomes and total mortality: a systematic review and meta-analysis of prospective observational studies.

Studies that investigated the association between tea consumption and the risk of major cardiovascular events have reported inconsistent results. We conducted a meta-analysis of prospective observational studies in order to summarize the evidence regarding the association between tea consumption and major cardiovascular outcomes or total mortality. In July 2014, we performed electronic searches in PubMed, EmBase, and the Cochrane Library, followed by manual searches of reference lists from the resulting articles to identify other relevant studies. Prospective observational studies that reported effect estimates, with 95% confidence intervals (CIs), for coronary heart disease (CHD), stroke, cardiac death, stroke death, or total mortality for more than two dosages of tea consumption were included. A random-effects meta-analysis was performed to determine the risk of major cardiovascular outcomes associated with an increase in tea consumption by 3 cups per day. Of the 736 citations identified from database searches, we included 22 prospective studies from 24 articles reporting data on 856,206 individuals, and including 8,459 cases of CHD, 10,572 of stroke, 5,798 cardiac deaths, 2,350 stroke deaths, and 13,722 total deaths. Overall, an increase in tea consumption by 3 cups per day was associated with a reduced risk of CHD (relative risk [RR], 0.73; 95% CI: 0.53-0.99; P = 0.045), cardiac death (RR, 0.74; 95% CI: 0.63-0.86; P < 0.001), stroke (RR, 0.82; 95% CI: 0.73-0.92; P = 0.001), total mortality (RR, 0.76; 95% CI: 0.63-0.91; P = 0.003), cerebral infarction (RR, 0.84; 95% CI: 0.72-0.98; P = 0.023), and intracerebral hemorrhage (RR, 0.79; 95% CI: 0.72-0.87; P < 0.001), but had little or no effect on stroke mortality (RR, 0.93; 95% CI: 0.83-1.05; P = 0.260). The findings from this meta-analysis indicate that increased tea consumption is associated with a reduced risk of CHD, cardiac death, stroke, cerebral infarction, and intracerebral hemorrhage, as well as total mortality.

Tea consumption and the incidence of cancer: a systematic review and meta-analysis of prospective observational studies.

The aim of this study was to summarize the current evidence on the strength of associations between tea consumption and the incidence of cancer at different sites. We searched PubMed, Embase and the Cochrane Library for relevant articles published before October 2013. Prospective studies that reported effect estimates of cancer incidence, with 95% confidence intervals (CIs), for more than two categories of tea consumption were included. We analysed 87 datasets (57 articles), which included a total of 49,812 incident cases. Overall, high tea consumption had no significant effect on the risk of gastric, rectal, colon, lung, pancreatic, liver, breast, prostate, ovarian, bladder cancers or gliomas. However, high tea consumption was associated with a reduced risk of oral cancer (risk ratio 0.72; 95% CI 0.54-0.95; P=0.021). A dose-response meta-analysis suggested that an increase in tea consumption by one cup per day was associated with a reduced risk of oral cancer (risk ratio 0.89; 95% CI 0.80-0.98; P=0.022), but had little effect on the incidence of other cancers. Subgroup analysis indicated that an increase in the consumption of black tea by one cup per day was associated with an increased risk of breast cancer. Moreover, in western countries, we found that an increase in the consumption of tea by one cup per day was associated with a reduced risk of bladder cancer. Increased tea consumption has no significant effect on the risk of common malignancies. For some cancer types, associations differ according to sex, ethnicity and tea type.

Association between B vitamins supplementation and risk of cardiovascular outcomes: a cumulative meta-analysis of randomized controlled trials.

BACKGROUND: Observational studies suggest that B vitamin supplementation reduces cardiovascular risk in adults, but this association remains controversial. This study aimed to summarize the evidence from randomized controlled trials (RCTs) investigating B vitamin supplementation for the primary or secondary prevention of major adverse cardiovascular outcomes and to perform a cumulative meta-analysis to determine the evidence base. METHODOLOGY AND PRINCIPAL FINDINGS: In April 2013, we searched PubMed, Embase, and the Cochrane Library to identify relevant RCTs. We included RCTs investigating the effect of B vitamin supplementation on cardiovascular outcome. Relative risk (RR) was used to measure the effect using a random-effect model. Statistical heterogeneity scores were assessed using the Q statistic. We included data on 57,952 individuals from 24 RCTs: 12 primary prevention trials and 12 secondary prevention trials. In 23 of these trials, 10,917 major adverse cardiovascular events (MACE) occurred; in 20 trials, 7,203 deaths occurred; in 15 trials, 3,422 cardiac deaths occurred; in 19 trials, 3,623 myocardial infarctions (MI) occurred; and in 18 trials, 2,465 strokes occurred. B vitamin supplementation had little or no effect on the incidence of MACE (RR, 0.98; 95% confidence interval [CI]: 0.93-1.03; P = 0.37), total mortality (RR, 1.01; 95% CI: 0.97-1.05; P = 0.77), cardiac death (RR, 0.96; 95% CI: 0.90-1.02; P = 0.21), MI (RR, 0.99; 95% CI: 0.93-1.06; P = 0.82), or stroke (RR, 0.94; 95% CI: 0.85-1.03; P = 0.18). CONCLUSION/SIGNIFICANCE: B vitamin supplementation, when used for primary or secondary prevention, is not associated with a reduction in MACE, total mortality, cardiac death, MI, or stroke.

Polyunsaturated fatty acid intake and risk of lung cancer: a meta-analysis of prospective studies.

BACKGROUND: Studies have reported inconsistent results for the existence of an association between polyunsaturated fatty acid (PUFA) intake and risk of lung cancer. The purpose of this study is to summarize the evidence regarding this relationship using a dose response meta-analytic approach. METHODOLOGY AND PRINCIPAL FINDINGS: We searched the PubMed, EmBase, and Cochrane Library electronic databases for related articles published through July 2013. Only prospective studies that reported effect estimates with 95% confidence intervals (CIs) of lung cancer incidence for greater than 2 categories of PUFA intake were included. We did random-effects meta-analyses of study-specific incremental estimates to determine the risk of lung cancer associated with a 5 g per day increase in PUFA intake. Overall, we included 8 prospective cohort studies reporting data on 1,268,442 individuals. High PUFA intake had little or no effect on lung cancer risk (risk ratio [RR], 0.91; 95% CI, 0.78-1.06; P = 0.230). Furthermore, the dose-response meta-analysis also suggested that a 5 g per day increase in PUFA has no significant effect on the risk of lung cancer (RR, 0.98; 95%CI: 0.96-1.01; P = 0.142). Finally, the findings of dose response curve suggested that PUFA intake of up to 15 g/d seemed to increase the risk of lung cancer. Furthermore, PUFA intake greater than 15 g/d was associated with a small beneficial effect and borderline statistical significance. Subgroup analyses for 5 g per day increment in PUFA indicated that the protective effect of PUFA was more evident in women (RR, 0.94; 95% CI, 0.87-1.01; P = 0.095) than in men (RR, 1.00; 95% CI, 0.98-1.02; P = 0.784). CONCLUSION/SIGNIFICANCE: Our study indicated that PUFA intake had little or no effect on lung cancer risk. PUFA intake might play an important role in lung cancer prevention in women.

Effect of omega-3 fatty acid supplementation on cancer incidence, non-vascular death, and total mortality: a meta-analysis of randomized controlled trials.

BACKGROUND: Omega-3 fatty acids are known to prevent cardiac death. However, previous observational studies have suggested that omega-3 fatty acids are associated with cancer risk in adults. We conducted a meta-analysis based on randomized controlled trials to evaluate the effect of omega-3 fatty acids on the risk of cancer incidence, nonvascular death, and total mortality. METHODS: In February 2013, we performed electronic searches in PubMed, EmBase, and the Cochrane Library to identify randomized controlled trials on cancer incidence, nonvascular death, and total mortality. Relative risk (RR) was used to measure the effect of omega-3 fatty acid supplementation on the risk of cancer incidence, nonvascular death, and total mortality using a random-effect model. The analysis was further stratified by factors that could affect the treatment effects. RESULTS: Of the 8,746 identified articles, we included 19 trials reporting data on 68,954 individuals. These studies reported 1,039 events of cancer, 2,439 events of nonvascular death, and 7,025 events of total mortality. Omega-3 fatty acid supplementation had no effect on cancer incidence (RR, 1.10; 95% CI: 0.97-1.24; P = 0.12), nonvascular death (RR, 1.00; 95% CI: 0.93-1.08; P = 1.00), or total mortality (RR, 0.95; 95% CI: 0.88-1.03; P = 0.24) when compared to a placebo. Subgroup analysis indicated that omega-3 fatty acid supplementation was associated with a reduction in total mortality risk if the proportion of men in the study population was more than 80%, or participants received alpha-linolenic acid. CONCLUSIONS: Omega-3 fatty acid supplementation does not have an effect on cancer incidence, nonvascular death, or total mortality.

Effects of zinc supplementation on the incidence of mortality in preschool children: a meta-analysis of randomized controlled trials.

BACKGROUND: Previous trials have shown that zinc supplementation can decrease the risk of diarrhea, pneumonia, and malaria in children; however, the effects of zinc supplementation on mortality remain unclear. This study aimed at evaluating the benefits and risks of zinc supplementation on both total mortality and cause-specific mortality. METHODOLOGY AND PRINCIPAL FINDINGS: We searched PubMed, EmBase, and the Cochrane Central Register of Controlled Trials to identify randomized controlled trials in preschool children reporting total mortality or cause-specific mortality. Relative risk (RR) was used as a measure of the effect of zinc supplementation on the risk of mortality using a random effect model. Of the 1,520 identified articles, we included 8 trials reporting data on 87,854 children. Overall, zinc supplementation had no effect on total mortality (RR, 0.76; 95% CI: 0.56-1.04; P = 0.084), diarrhea-related mortality (RR, 0.80; 95% CI: 0.53-1.20; P = 0.276), pneumonia-related mortality (RR, 0.52; 95% CI: 0.11-2.39; P = 0.399), malaria-related mortality (RR, 0.90; 95% CI: 0.77-1.06; P = 0.196), or other causes of mortality (RR, 0.98; 95% CI: 0.67-1.44; P = 0.917). Subgroup analysis indicated that zinc supplementation was associated with a reduction in total mortality risk if the participants were boys, aged greater than 12 months, and the duration of the follow-up period was less than 12 months. CONCLUSIONS/SIGNIFICANCE: Zinc supplementation does not have an effect on total mortality, diarrhea-related mortality, pneumonia-related mortality, malaria-related mortality, or other causes of mortality. Subgroup analysis suggested that zinc supplementation can effectively reduce the risk of total mortality if the participants were boys, aged greater than 12 months, and the duration of the follow-up period was less than 12 months.

Effect of B-vitamin supplementation on stroke: a meta-analysis of randomized controlled trials.

BACKGROUND: B vitamins have been extensively used to reduce homocysteine levels; however, it remains uncertain whether B vitamins are associated with a reduced risk of stroke. Our aim was to evaluate the effects of B vitamins on stroke. METHODOLOGY AND PRINCIPAL FINDINGS: We systematically searched PubMed, EmBase, and the Cochrane Central Register of Controlled Trials to identify studies for our analysis. Relative risk (RR) was used to measure the effect of B-vitamin supplementation on the risk of stroke. The analysis was further stratified based on factors that could affect the treatment effects. Of the 13,124 identified articles, we included 18 trials reporting data on 57,143 individuals and 2,555 stroke events. B-vitamin supplementation was not associated with a significant reduction in the risk of stroke (RR, 0.91, 95%CI: 0.82-1.01, P = 0.075; RD, -0.003, 95%CI: -0.007-0.001, P = 0.134). Subgroup analyses suggested that B-vitamin supplementation might reduce the risk of stroke if included trials had a man/woman ratio of more than 2 or subjects received dose of folic acid less than 1 mg. Furthermore, in a cumulative meta-analysis for stroke, the originally proposed nonsignificant B-vitamin effect was refuted by the evidence accumulated up to 2006. There is a small effect with borderline statistical significance based on data gathered since 2007. CONCLUSIONS/SIGNIFICANCE: Our study indicates that B-vitamin supplementation is not associated with a lower risk of stroke based on relative and absolute measures of association. Subgroup analyses suggested that B-vitamin supplementation can effectively reduce the risk of stroke if included trials had a man/woman ratio of more than 2 or subjects received dose of folic acid less than 1 mg.

Effect of calcium or vitamin D supplementation on vascular outcomes: a meta-analysis of randomized controlled trials.

BACKGROUND: Whether calcium or vitamin D supplementation reduces serious vascular outcomes in older people remains unclear. We conducted a meta-analysis based on randomized controlled trials to evaluate the effect of calcium or vitamin D supplementation on the risk of major cardiovascular outcomes. METHODS: We performed electronic searches in PubMed, Embase, and the Cochrane Library to identify relevant randomized controlled trials. Odds ratios (ORs) were used to measure the effect of calcium or vitamin D supplementation on the risk of major vascular outcomes with a random-effect model. RESULTS: Of the 1643 identified studies, we included 11 trials reporting data on 50,252 individuals. These studies reported 2685 major cardiovascular events, 1097 events of myocardial infarction, and 1350 events of stroke. Calcium or vitamin D supplementation did not have an effect on major cardiovascular events (OR, 1.03; 95% confidence interval [CI]: 0.94-1.12; P=0.54), myocardial infarction (OR, 1.08; 95% CI: 0.96-1.22; P=0.21), or stroke (OR, 1.01; 95% CI: 0.91-1.13; P=0.80) when compared to the effect with a placebo. Subgroup analysis indicated that calcium supplementation alone might play an important role in increasing the risk of major cardiovascular events, myocardial infarction, and stroke, but this difference could not be identified as statistically significant. Furthermore, males seem to experience more harmful effects with supplements of calcium or vitamin D than the effects experienced by females. CONCLUSIONS: Calcium supplementation might increase the risk of major cardiovascular events, myocardial infarction, and stroke compared to the risk with a placebo.

Effect of folic acid supplementation on cardiovascular outcomes: a systematic review and meta-analysis.

BACKGROUND: Folic acid is widely used to lower homocysteine concentrations and prevent adverse cardiovascular outcomes. However, the effect of folic acid on cardiovascular events is not clear at the present time. We carried out a comprehensive systematic review and meta-analysis to assess the effects of folic acid supplementation on cardiovascular outcomes. METHODOLOGY AND PRINCIPAL FINDINGS: We systematically searched Medline, EmBase, the Cochrane Central Register of Controlled Trials, reference lists of articles, and proceedings of major meetings for relevant literature. We included randomized placebo-controlled trials that reported on the effects of folic acid on cardiovascular events compared to placebo. Of 1594 identified studies, we included 16 trials reporting data on 44841 patients. These studies reported 8238 major cardiovascular events, 2001 strokes, 2917 myocardial infarctions, and 6314 deaths. Folic acid supplementation as compared to placebo had no effect on major cardiovascular events (RR, 0.98; 95% CI, 0.93-1.04), stroke (RR, 0.89; 95% CI,0.78-1.01), myocardial infarction (RR, 1.00; 95% CI, 0.93-1.07), or deaths from any cause (RR, 1.00;95% CI, 0.96-1.05). Moreover, folic acid as compared to placebo also had no effect on the following secondary outcomes: risk of revascularization (RR, 1.05; 95%CI, 0.95-1.16), acute coronary syndrome (RR, 1.06; 95%CI, 0.97-1.15), cancer (RR, 1.08; 95%CI, 0.98-1.21), vascular death (RR, 0.94; 95%CI,0.88-1.02), or non-vascular death (RR, 1.06; 95%CI, 0.97-1.15). CONCLUSION/SIGNIFICANCE: Folic acid supplementation does not effect on the incidence of major cardiovascular events, stroke, myocardial infarction or all cause mortality.