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International Journal of Cancer May 2015Use of dietary supplements is rising in countries where colorectal cancer is prevalent. We conducted a systematic literature review and meta-analyses of prospective... (Meta-Analysis)
Meta-Analysis Review
Use of dietary supplements is rising in countries where colorectal cancer is prevalent. We conducted a systematic literature review and meta-analyses of prospective cohort studies on dietary supplement use and colorectal cancer risk. We identified relevant studies in Medline, Embase and Cochrane up to January 2013. Original and peer-reviewed papers on dietary supplement use and colorectal cancer, colon cancer, or rectal cancer incidence were included. "Use-no use"(U-NU), "highest-lowest"(H-L) and "dose-response"(DR) meta-analyses were performed. Random-effects models were used to estimate summary estimates. In total, 24 papers were included in the meta-analyses. We observed inverse associations for colorectal cancer risk and multivitamin (U-NU: RR = 0.92; 95% CI: 0.87,0.97) and calcium supplements (U-NU: RR = 0.86; 95% CI: 0.79,0.95; H-L: RR = 0.80; 95% CI: 0.70,0.92; DR: for an increase of 100 mg/day, RR = 0.96; 95% CI: 0.94,0.99). Inconsistent associations were found for colon cancer risk and supplemental vitamin A and vitamin C, and for colorectal cancer risk and supplemental vitamin D, vitamin E, garlic and folic acid. Meta-analyses of observational studies suggest a beneficial role for multivitamins and calcium supplements on colorectal cancer risk, while the association with other supplements and colorectal cancer risk is inconsistent. Residual confounding of lifestyle factors might be present. Before recommendations can be made, an extensive assessment of dietary supplement use and a better understanding of underlying mechanisms is needed.
Topics: Adult; Aged; Aged, 80 and over; Calcium, Dietary; Colorectal Neoplasms; Databases as Topic; Dietary Supplements; Female; Humans; Male; Middle Aged; Prospective Studies; Risk Factors; Vitamins; Young Adult
PubMed: 25335850
DOI: 10.1002/ijc.29277 -
The Cochrane Database of Systematic... Jan 2011Miscarriage is a common complication of pregnancy that can be caused by a wide range of factors. Poor dietary intake of vitamins has been associated with an increased... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Miscarriage is a common complication of pregnancy that can be caused by a wide range of factors. Poor dietary intake of vitamins has been associated with an increased risk of miscarriage, therefore supplementing women with vitamins either prior to or in early pregnancy may help prevent miscarriage.
OBJECTIVES
The objectives of this review are to determine the effectiveness and safety of any vitamin supplementation, on the risk of spontaneous miscarriage, maternal adverse outcomes and fetal and infant adverse outcomes.
SEARCH STRATEGY
We searched the Cochrane Pregnancy and Childbirth Group Trials Register (21 June 2010).
SELECTION CRITERIA
All randomised and quasi-randomised trials comparing one or more vitamins with either placebo, other vitamins, no vitamins or other interventions, prior to conception, periconceptionally or in early pregnancy (less than 20 weeks' gestation).
DATA COLLECTION AND ANALYSIS
At least two review authors independently assessed trials for inclusion, extracted data and assessed trial quality.
MAIN RESULTS
We identified 28 trials assessing supplementation with any vitamin(s) starting prior to 20 weeks' gestation and reporting at least one primary outcome that was eligible for the review. Overall, the included trials involved 96,674 women and 98,267 pregnancies. Three trials were cluster randomised and combined contributed data for 62,669 women and 64,210 pregnancies in total. No significant differences were seen between women taking any vitamins compared with controls for total fetal loss (relative risk (RR) 1.04, 95% confidence interval (CI) 0.95 to 1.14), early or late miscarriage (RR 1.09, 95% CI 0.95 to 1.25) or stillbirth (RR 0.86, 95% CI 0.65 to 1.13) and most of the other primary outcomes, using fixed-effect models. Compared with controls, women given any type of vitamin(s) pre or peri-conception were more likely to have a multiple pregnancy (RR 1.38, 95% CI 1.12 to 1.70, three trials, 20,986 women).
AUTHORS' CONCLUSIONS
Taking any vitamin supplements prior to pregnancy or in early pregnancy does not prevent women experiencing miscarriage or stillbirth. However, women taking vitamin supplements may be more likely to have a multiple pregnancy. There is insufficient evidence to examine the effects of different combinations of vitamins on miscarriage, stillbirth or other maternal and infant outcomes.
Topics: Abortion, Habitual; Abortion, Spontaneous; Ascorbic Acid; Dietary Supplements; Female; Humans; Pre-Eclampsia; Pregnancy; Pregnancy Outcome; Pregnancy, Multiple; Randomized Controlled Trials as Topic; Vitamin A; Vitamins
PubMed: 21249660
DOI: 10.1002/14651858.CD004073.pub3 -
Advances in Nutrition (Bethesda, Md.) Jun 2021Vitamin A (VA) is an essential nutrient often lacking in the diets of people in developing countries. Accurate biomarkers of VA status are vital to inform public health... (Meta-Analysis)
Meta-Analysis
Vitamin A (VA) is an essential nutrient often lacking in the diets of people in developing countries. Accurate biomarkers of VA status are vital to inform public health policy and monitor interventions. The relative dose-response (RDR) and modified-RDR (MRDR) tests are semi-quantitative screening tests for VA deficiency that have been used in Demographic and Health Surveys and VA intervention studies. A systematic review and meta-analysis of sensitivity and specificity were conducted to summarize the physiological evidence to support the RDR tests as methods to assess VA status and investigate the impact of different pathological and physiological states on the tests. A total of 190 studies were screened for inclusion, with 21 studies comparing the RDR tests with the gold-standard biomarker, liver VA concentration (68% and 80% sensitivity and 85% and 69% specificity for the RDR and MRDR, respectively). Nearly all studies with VA interventions in VA-deficient populations demonstrated a response of the tests to VA intake that would be expected to improve VA status. The impacts of chronic liver disease, protein malnutrition, age, pregnancy and lactation, infection and inflammation, and various other conditions were examined in 51 studies. The RDR and MRDR tests were reported to have been used in 39 observational studies, and the MRDR has been used in at least 6 national micronutrient surveys. The RDR and MRDR are sensitive tests for determining population VA status and assessing VA interventions. Although they are robust to most physiological and pathological states, caution may be warranted when using the tests in neonates, individuals with chronic liver disease, and those with protein or iron malnutrition. Research on further improvements to the tests to increase accessibility, such as sampling breast milk instead of blood or using intramuscular doses in subjects with malabsorption, will allow wider adoption. This review was registered with PROSPERO as CRD42019124180.
Topics: Breast Feeding; Dose-Response Relationship, Drug; Female; Humans; Infant, Newborn; Lactation; Milk, Human; Nutritional Status; Vitamin A; Vitamin A Deficiency
PubMed: 33130884
DOI: 10.1093/advances/nmaa136 -
Nutrients Apr 2024This review aims to evaluate the efficacy of any vitamin administration(s) in preventing and managing COVID-19 and/or long-COVID. Databases were searched up to May 2023... (Meta-Analysis)
Meta-Analysis Review
The Efficacy of Multivitamin, Vitamin A, Vitamin B, Vitamin C, and Vitamin D Supplements in the Prevention and Management of COVID-19 and Long-COVID: An Updated Systematic Review and Meta-Analysis of Randomized Clinical Trials.
This review aims to evaluate the efficacy of any vitamin administration(s) in preventing and managing COVID-19 and/or long-COVID. Databases were searched up to May 2023 to identify randomized clinical trials comparing data on the effects of vitamin supplementation(s) versus placebo or standard of care on the two conditions of interest. Inverse-variance random-effects meta-analyses were conducted to estimate pooled risk ratios (RRs) and 95% confidence intervals (CIs) for all-cause mortality between supplemented and non-supplemented individuals. Overall, 37 articles were included: two regarded COVID-19 and long-COVID prevention and 35 records the COVID-19 management. The effects of vitamin D in preventing COVID-19 and long-COVID were contrasting. Similarly, no conclusion could be drawn on the efficacy of multivitamins, vitamin A, and vitamin B in COVID-19 management. A few positive findings were reported in some vitamin C trials but results were inconsistent in most outcomes, excluding all-cause mortality (RR = 0.84; 95% CI: 0.72-0.97). Vitamin D results were mixed in most aspects, including mortality, in which benefits were observed in regular administrations only (RR = 0.67; 95% CI: 0.49-0.91). Despite some benefits, results were mostly contradictory. Variety in recruitment and treatment protocols might explain this heterogeneity. Better-designed studies are needed to clarify these vitamins' potential effects against SARS-CoV-2.
Topics: Humans; Dietary Supplements; COVID-19; Vitamins; Vitamin D; Randomized Controlled Trials as Topic; Ascorbic Acid; SARS-CoV-2; Vitamin A; COVID-19 Drug Treatment; Vitamin B Complex
PubMed: 38732592
DOI: 10.3390/nu16091345 -
Archives of Dermatology Apr 2012To summarize the current state of evidence for combination topical and systemic therapies for mild to severe psoriasis. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To summarize the current state of evidence for combination topical and systemic therapies for mild to severe psoriasis.
DATA SOURCES
We performed a systematic search for all entries in PubMed, CINAHL, Cochrane Review, and EMBASE related to combination treatments for psoriasis through July 2010.
STUDY SELECTION
We included randomized controlled trials that reported proportion of disease clearance or mean change in clinical severity score (or provided these data through communication with study authors) for efficacy of a combination treatment for psoriasis compared with 1 or more corresponding monotherapies.
DATA EXTRACTION
Study data were extracted by 3 independent investigators, with disagreement resolved by consensus. The proportion of patients who achieved clearance, definition of clearance, means and standard deviations for baseline disease symptom score and final disease symptom score, and major design characteristics were extracted for each study.
DATA SYNTHESIS
Combination treatments consisting of vitamin D derivative and corticosteroid, vitamin D derivative and UV-B, vitamin A derivative and psoralen-UV-A, vitamin A derivative and corticosteroid, vitamin A derivative and UV-B, corticosteroid and hydrocolloid occlusion dressings, UV-B and alefacept, and vitamins A and D derivatives were more effective than 1 or more monotherapies using the likelihood of clearance as the outcome. Blinding status and potency of the corticosteroid treatment used were significant sources of heterogeneity between studies.
CONCLUSIONS
The results demonstrate the need for additional long-term trials with standardized outcome measures to evaluate the efficacy and adverse effects of combination therapies for psoriasis and highlight the possible effects of trial design characteristics on results.
Topics: Adrenal Cortex Hormones; Balneology; Bandages, Hydrocolloid; Combined Modality Therapy; Dermatologic Agents; Drug Therapy, Combination; Humans; Immunosuppressive Agents; PUVA Therapy; Psoriasis; Ultraviolet Therapy; Vitamin A; Vitamin D; Vitamins
PubMed: 22184718
DOI: 10.1001/archdermatol.2011.1916 -
BMC Public Health 2013Financial incentives are widely used strategies to alleviate poverty, foster development, and improve health. Cash transfer programs, microcredit, user fee removal... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Financial incentives are widely used strategies to alleviate poverty, foster development, and improve health. Cash transfer programs, microcredit, user fee removal policies and voucher schemes that provide direct or indirect monetary incentives to households have been used for decades in Latin America, Sub-Saharan Africa, and more recently in Southeast Asia. Until now, no systematic review of the impact of financial incentives on coverage and uptake of health interventions targeting children under 5 years of age has been conducted. The objective of this review is to provide estimates on the effect of six types of financial incentive programs: (i) Unconditional cash transfers (CT), (ii) Conditional cash transfers (CCT), (iii) Microcredit (MC), (iv) Conditional Microcredit (CMC), (v) Voucher schemes (VS) and (vi) User fee removal (UFR) on the uptake and coverage of health interventions targeting children under the age of five years.
METHODS
We conducted systematic searches of a series of databases until September 1st, 2012, to identify relevant studies reporting on the impact of financial incentives on coverage of health interventions and behaviors targeting children under 5 years of age. The quality of the studies was assessed using the CHERG criteria. Meta-analyses were undertaken to estimate the effect when multiple studies meeting our inclusion criteria were available.
RESULTS
Our searches resulted in 1671 titles identified 25 studies reporting on the impact of financial incentive programs on 5 groups of coverage indicators: breastfeeding practices (breastfeeding incidence, proportion of children receiving colostrum and early initiation of breastfeeding, exclusive breastfeeding for six months and duration of breastfeeding); vaccination (coverage of full immunization, partial immunization and specific antigens); health care use (seeking healthcare when child was ill, visits to health facilities for preventive reasons, visits to health facilities for any reason, visits for health check-up including growth control); management of diarrhoeal disease (ORS use during diarrhea episode, continued feeding during diarrhea, healthcare during diarrhea episode) and other preventive health interventions (iron supplementation, vitamin A, zinc supplementation, preventive deworming). The quality of evidence on the effect of financial incentives on breastfeeding practices was low but seems to indicate a potential positive impact on receiving colostrum, early initiation of breastfeeding, exclusive breastfeeding and mean duration of exclusive breastfeeding. There is no effect of financial incentives on immunization coverage although there was moderate quality evidence of conditional cash transfers leading to a small but non-significant increase in coverage of age-appropriate immunization. There was low quality evidence of impact of CCT on healthcare use by children under age 5 (Risk difference: 0.14 [95%CI: 0.03; 0.26]) as well as low quality evidence of an effect of user fee removal on use of curative health services (RD=0.62 [0.41; 0.82]).
CONCLUSIONS
Financial incentives may have potential to promote increased coverage of several important child health interventions, but the quality of evidence available is low. The more pronounced effects seem to be achieved by programs that directly removed user fees for access to health services. Some indication of effect were also observed for programs that conditioned financial incentives on participation in health education and attendance to health care visits. This finding suggest that the measured effect may be less a consequence of the financial incentive and more due to conditionalities addressing important informational barriers.
Topics: Africa South of the Sahara; Asia, Southeastern; Breast Feeding; Child; Child Health Services; Child Welfare; Female; Health Promotion; Humans; Infant; Infant Death; Latin America; Male; Malnutrition; Quality Improvement; Quality of Health Care; Reimbursement, Incentive
PubMed: 24564520
DOI: 10.1186/1471-2458-13-S3-S30 -
Systematic Reviews Aug 2013Vitamins and minerals are essential for growth and metabolism. The World Health Organization estimates that more than 2 billion people are deficient in key vitamins and... (Review)
Review
BACKGROUND
Vitamins and minerals are essential for growth and metabolism. The World Health Organization estimates that more than 2 billion people are deficient in key vitamins and minerals. Groups most vulnerable to these micronutrient deficiencies are pregnant and lactating women and young children, given their increased demands. Food fortification is one of the strategies that has been used safely and effectively to prevent vitamin and mineral deficiencies.
METHODS
A comprehensive search was done to identify all available evidence for the impact of fortification interventions. Studies were included if food was fortified with a single, dual or multiple micronutrients and impact of fortification was analyzed on the health outcomes and relevant biochemical indicators of women and children. We performed a meta-analysis of outcomes using Review Manager Software version 5.1.
RESULTS
Our systematic review identified 201 studies that we reviewed for outcomes of relevance. Fortification for children showed significant impacts on increasing serum micronutrient concentrations. Hematologic markers also improved, including hemoglobin concentrations, which showed a significant rise when food was fortified with vitamin A, iron and multiple micronutrients. Fortification with zinc had no significant adverse impact on hemoglobin levels. Multiple micronutrient fortification showed non-significant impacts on height for age, weight for age and weight for height Z-scores, although they showed positive trends. The results for fortification in women showed that calcium and vitamin D fortification had significant impacts in the post-menopausal age group. Iron fortification led to a significant increase in serum ferritin and hemoglobin levels in women of reproductive age and pregnant women. Folate fortification significantly reduced the incidence of congenital abnormalities like neural tube defects without increasing the incidence of twinning. The number of studies pooled for zinc and multiple micronutrients for women were few, though the evidence suggested benefit. There was a dearth of evidence for the impact of fortification strategies on morbidity and mortality outcomes in women and children.
CONCLUSION
Fortification is potentially an effective strategy but evidence from the developing world is scarce. Programs need to assess the direct impact of fortification on morbidity and mortality.
Topics: Body Height; Body Weight; Child; Child Development; Female; Folic Acid; Food, Fortified; Humans; Iodine; Iron, Dietary; Micronutrients; Nutritional Status; Vitamin A; Vitamin D; Women's Health; Zinc
PubMed: 23971426
DOI: 10.1186/2046-4053-2-67 -
The Cochrane Database of Systematic... Apr 2005Vitamins have been reported to be effective in controlling certain types of seizures and to prevent some of the harmful effects of antiepileptic drugs (AEDs). In this... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Vitamins have been reported to be effective in controlling certain types of seizures and to prevent some of the harmful effects of antiepileptic drugs (AEDs). In this review we will summarize evidence from randomized controlled trials.
OBJECTIVES
To assess if vitamins improve seizure control, reduce adverse effects of AEDs or improve the quality of life in people with epilepsy.
SEARCH STRATEGY
We searched MEDLINE from 1966 to 2004, the Cochrane Epilepsy Group trials register (December 2004), CENTRAL (the Cochrane Controlled Trials Register) (TheCochraneLibrary Issue 4, 2004), and cross-references from identified studies.
SELECTION CRITERIA
Randomized or quasi-randomized studies investigating the effects of one or more vitamins given alone or in addition to AEDs to people of any age with any type of epilepsy.
DATA COLLECTION AND ANALYSIS
Both reviewers assessed the trials for inclusion and extracted the data. Outcomes assessed included seizure frequency, gingival hyperplasia, neuropathy, changes in bone mineral content, serum calcium, alkaline phosphatase, hemogram, serum levels of AEDs, neuropsychological and quality of life outcomes. Primary analyses were by intention to treat.
MAIN RESULTS
Fifteen studies met our inclusion criteria and were of poor methodological quality. None described randomization methods and most enrolled small numbers of participants. Nine studies (331 participants) investigated folic acid. Two studies (75 participants) found no effect for the outcome 50% or greater reduction in seizure frequency (OR 0.96; 95% CI 0.32 to 2.29). Also, no evidence was found for an effect on gingival health, intelligence, behavior, mental health or personality, or measures of red blood volume and hemoglobin content. Folic acid was not associated with any consistent changes in serum phenytoin or phenobarbitone levels or improvement in the mean motor conduction velocities of peripheral nerves. One small study (72 participants) found that thiamine improves neuropsychological functions related to psychomotor speed, visuospatial abilities, selective attention and verbal abstracting ability. One study (226 participants) found a significantly higher bone mineral content (BMC) among patients with epilepsy taking AEDs with vitamin D supplementation compared to controls who were not given supplementation (OR 3.6; 95% CI 2.48 to 4.72; p < 0.00001). The studies found no significant effects on serum calcium, alkaline phosphatase or general well-being. One small study (24 participants) found a significant decrease in seizure frequency in those treated with vitamin E compared to placebo (p = 0.00005; Peto OR 26.73; 95% CI 5.46 to 130.92).
AUTHORS' CONCLUSIONS
In view of methodological deficiencies and limited number of individual studies, we have found no reliable evidence to support the routine use of vitamins in patients with epilepsy. Further trials are needed, especially to assess the utility of vitamin D supplementation to prevent osteomalacia and the role of vitamin E on seizures and thiamine in improving cognitive functions.
Topics: Anticonvulsants; Epilepsy; Folic Acid; Humans; Randomized Controlled Trials as Topic; Thiamine; Vitamin A; Vitamin D; Vitamins
PubMed: 15846704
DOI: 10.1002/14651858.CD004304.pub2 -
International Breastfeeding Journal Jan 2021This study aims to systematically review the effects of maternal vitamin and/or mineral supplementation on the content of breast milk. (Review)
Review
BACKGROUND
This study aims to systematically review the effects of maternal vitamin and/or mineral supplementation on the content of breast milk.
METHODS
We systematically searched electronic databases including Medline via PubMed, Scopus and ISI Web of Science till May 24, 2018. The following terms were used systematically in all mentioned databases: ("human milk" OR "breast milk" OR "breast milk composition" OR "human breast milk composition" OR "composition breast milk" OR "mother milk" OR "human breast milk" OR "maternal milk") AND ("vitamin a" OR "retinol" OR "retinal" OR "retinoic acid" OR "beta-carotene" OR "beta carotene" OR "ascorbic acid" OR "l-ascorbic acid" OR "l ascorbic acid" OR "vitamin c" OR "vitamin d" OR "cholecalciferol" OR "ergocalciferol" OR "calciferol" OR "vitamin e" OR "tocopherol" OR "tocotrienol" OR "alpha-tocopherol" OR "alpha tocopherol" OR "α-tocopherol" OR "α tocopherol" OR "vitamin k" OR "vitamin b" OR "vitamin b complex" OR "zinc" OR "iron" OR "copper" Or "selenium" OR "manganese" OR "magnesium") and we searched Medline via Medical subject Headings (MeSH) terms. We searched Google Scholar for to increase the sensitivity of our search. The search was conducted on human studies, but it was not limited to the title and abstract. Methodological quality and risk of bias of included studies were evaluated by Jadad scale and Cochrane risk of bias tools, respectively.
RESULTS
This review included papers on three minerals (zinc, iron, selenium) and 6 vitamins (vitamin A, B, D, C, E and K) in addition to multi-vitamin supplements. Although studies had different designs, e.g. not using random allocation and/or blinding, our findings suggest that maternal use of some dietary supplements, including vitamin A, D, vitamin B1, B2 and vitamin C might be reflected in human milk. Vitamin supplements had agreater effect on breast milk composition compared to minerals. Higher doses of supplements showed higher effects and they were reflected more in colostrum than in the mature milk.
CONCLUSION
Maternal dietary vitamin and/or mineral supplementation, particularly fat- soluble vitamins, vitamin B1, B2 and C might be reflected in the breast milk composition. No difference was found between mega dose and single dose administration of minerals.
Topics: Dietary Supplements; Female; Humans; Milk, Human; Mothers; Selenium; Vitamin B Complex
PubMed: 33397426
DOI: 10.1186/s13006-020-00354-0 -
Molecular Psychiatry Oct 2023Adolescence represents a critical period for brain and behavioural health and characterised by the onset of mood, psychotic and anxiety disorders. In rodents,...
Adolescence represents a critical period for brain and behavioural health and characterised by the onset of mood, psychotic and anxiety disorders. In rodents, neurogenesis is very active during adolescence, when is particularly vulnerable to stress. Whether stress-related neurogenesis changes influence adolescence onset of psychiatric symptoms remains largely unknown. A systematic review was conducted on studies investigating changes in hippocampal neurogenesis and neuroplasticity, hippocampal-dependent cognitive functions, and behaviour, occurring after adolescence stress exposure in mice both acutely (at post-natal days 21-65) and in adulthood. A total of 37 studies were identified in the literature. Seven studies showed reduced hippocampal cell proliferation, and out of those two reported increased depressive-like behaviours, in adolescent rodents exposed to stress. Three studies reported a reduction in the number of new-born neurons, which however were not associated with changes in cognition or behaviour. Sixteen studies showed acutely reduced hippocampal neuroplasticity, including pre- and post-synaptic plasticity markers, dendritic spine length and density, and long-term potentiation after stress exposure. Cognitive impairments and depressive-like behaviours were reported by 11 of the 16 studies. Among studies who looked at adolescence stress exposure effects into adulthood, seven showed that the negative effects of stress observed during adolescence on either cell proliferation or hippocampal neuroplasticity, cognitive deficits and depressive-like behaviour, had variable impact in adulthood. Treating adolescent mice with antidepressants, glutamate receptor inhibitors, glucocorticoid antagonists, or healthy diet enriched in omega-3 fatty acids and vitamin A, prevented or reversed those detrimental changes. Future research should investigate the translational value of these preclinical findings. Developing novel tools for measuring hippocampal neurogenesis in live humans, would allow assessing neurogenic changes following stress exposure, investigating relationships with psychiatric symptom onset, and identifying effects of therapeutic interventions.
Topics: Animals; Mice; Brain; Cognition; Hippocampus; Neurogenesis; Rodentia; Stress, Psychological
PubMed: 37612364
DOI: 10.1038/s41380-023-02229-2