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Diabetic Medicine : a Journal of the... Sep 2016High iron measured using dietary intake and biomarkers is associated with Type 2 diabetes. It is uncertain whether a similar association exists for gestational diabetes... (Meta-Analysis)
Meta-Analysis Review
AIM
High iron measured using dietary intake and biomarkers is associated with Type 2 diabetes. It is uncertain whether a similar association exists for gestational diabetes mellitus. The aim of this systematic review was to conduct a cohort study examining first trimester body iron stores and subsequent risk of gestational diabetes, and to include these findings in a systematic review of all studies examining the association between maternal iron status, iron intake (dietary and supplemental) and the risk of gestational diabetes.
METHODS
Serum samples from women with first trimester screening were linked to birth and hospital records for data on maternal characteristics and gestational diabetes diagnosis. Blood was analysed for ferritin, soluble transferrin receptor and C-reactive protein. Associations between iron biomarkers and gestational diabetes were assessed using multivariate logistic regression. A systematic review and meta-analysis, registered with PROSPERO (CRD42014013663) included studies of all designs published in English from January 1995 to July 2015 that examined the association between iron and gestational diabetes and included an appropriate comparison group.
RESULTS
Of 3776 women, 3.4% subsequently developed gestational diabetes. Adjusted analyses found increased odds of gestational diabetes for ferritin (OR 1.41; 95% CI 1.11, 1.78), but not for soluble transferrin receptor (OR 1.00; 95% CI 0.97, 1.03) per unit increase of the biomarker. Two trials of iron supplementation found no association with gestational diabetes. Increased risk of gestational diabetes was associated with higher levels of ferritin and serum iron and dietary haem iron intakes.
CONCLUSIONS
Increased risk of gestational diabetes among women with high serum ferritin and iron levels and dietary haem iron intakes warrants further investigation.
Topics: Adult; C-Reactive Protein; Diabetes, Gestational; Dietary Supplements; Female; Ferritins; Humans; Iron, Dietary; Logistic Models; Multivariate Analysis; New South Wales; Odds Ratio; Pregnancy; Prospective Studies; Receptors, Transferrin; Risk Factors; Young Adult
PubMed: 26670627
DOI: 10.1111/dme.13056 -
Nutrients Oct 2020Several studies indicate that oxidative stress might play a central role in the initiation and maintenance of cardiovascular diseases. It remains unclear whether...
Several studies indicate that oxidative stress might play a central role in the initiation and maintenance of cardiovascular diseases. It remains unclear whether ceruloplasmin acts as a passive marker of inflammation or as a causal mediator. To better understand the impact of ceruloplasmin blood levels on the risk of cardiovascular disease, and paying special attention to coronary heart disease, we conducted a search on the two most commonly used electronic databases (Medline via PubMed and EMBASE) to analyze current assessment using observational studies in the general adult population. Each study was quality rated using criteria developed by the US Preventive Services Task Force. Most of 18 eligible studies reviewed support a direct relationship between ceruloplasmin elevated levels and incidence of coronary heart disease. Our results highlight the importance of promoting clinical trials that determine the functions of ceruloplasmin as a mediator in the development of coronary heart disease and evaluate whether the treatment of elevated ceruloplasmin levels has a role in the prognosis or prevention of this condition.
Topics: Aged; Ceruloplasmin; Coronary Disease; Female; Heart Disease Risk Factors; Humans; Incidence; Inflammation; Male; Middle Aged
PubMed: 33096845
DOI: 10.3390/nu12103219 -
Obesity Reviews : An Official Journal... Feb 2012A growing number of studies suggest a potential link between obesity and altered iron metabolism. The purpose of this systematic review was to examine existing... (Review)
Review
A growing number of studies suggest a potential link between obesity and altered iron metabolism. The purpose of this systematic review was to examine existing literature on iron status in obese populations. A comprehensive literature search was conducted. Included studies recruited participants ≥ 18 years with a body mass index ≥ 30 kg m(-2) and provided descriptive statistics for haemoglobin or ferritin at a minimum. There were 25 studies meeting all eligibility criteria, of these 10 examined iron status in free-living obese individuals and 15 reported baseline iron biomarkers from bariatric surgery candidates. Non-obese comparison groups were used by 10 (40%) articles. In these, seven obese groups reported higher mean haemoglobin concentration; six reported significantly higher ferritin concentration; and four significantly lower transferrin saturation. Due to insufficient data, it was not possible to make conclusions regarding mean differences for soluble transferrin receptor (sTfR), hepcidin or C-reactive protein. Existing evidence suggests a tendency for higher haemoglobin and ferritin concentration and lower transferrin saturation in obesity. Alternation of iron biomarkers in obese populations may be a result of obesity-related inflammation and/or related comorbidities. Further research incorporating measurement of inflammatory cytokines, sTfR and hepcidin is required to confirm the impact of obesity on iron status.
Topics: Body Mass Index; Body Weight; C-Reactive Protein; Ferritins; Hemoglobins; Humans; Iron; Iron Deficiencies; Obesity; Receptors, Transferrin; Transferrin
PubMed: 21981048
DOI: 10.1111/j.1467-789X.2011.00938.x -
Birth Defects Research Oct 2022Congenital anomalies affect over 2% of pregnancies, with congenital heart disease (CHD) the most common. Understanding of causal factors is limited. Micronutrients are... (Review)
Review
BACKGROUND
Congenital anomalies affect over 2% of pregnancies, with congenital heart disease (CHD) the most common. Understanding of causal factors is limited. Micronutrients are essential trace elements with key roles in growth and development. We aimed to investigate whether maternal micronutrient deficiencies increase the risk of fetal CHD through systematic review of published literature.
METHOD
We performed a systematic review registered at PROSPERO as CRD42021276699. Ovid-MEDLINE, Ovid-EMBASE, and Cochrane Library were searched from their inception until September 7, 2021. Case control trials were included with a population of biological mothers of fetuses with and without CHD. The exposure was maternal micronutrient level measured in pregnancy or the postpartum period. Data extraction was performed by one author and checked by a second. Risk of bias assessment was performed according to the Scottish Intercollegiate Guidelines Network guidance. We performed a narrative synthesis for analysis.
RESULTS
726 articles were identified of which 8 met our inclusion criteria. Final analysis incorporated data from 2,427 pregnancies, 1,199 of which were complicated by fetal CHD assessing 8 maternal micronutrients: vitamin D, vitamin B12, folate, vitamin A, zinc, copper, selenium, and ferritin. Studies were heterogenous with limited sample sizes and differing methods and timing of maternal micronutrient sampling. Definitions of deficiency varied and differed from published literature. Published results were contradictory.
CONCLUSION
There is not enough evidence to confidently conclude if maternal micronutrient deficiencies increase the risk of fetal CHD. Further large-scale prospective study is required to answer this question.
Topics: Copper; Female; Ferritins; Folic Acid; Heart Defects, Congenital; Humans; Malnutrition; Maternal Nutritional Physiological Phenomena; Micronutrients; Observational Studies as Topic; Pregnancy; Selenium; Trace Elements; Vitamin A; Vitamin B 12; Vitamin D; Zinc
PubMed: 35979646
DOI: 10.1002/bdr2.2072 -
Role of iron biomarkers and iron intakes in lung cancer risk: A systematic review and meta-analysis.Journal of Trace Elements in Medicine... Dec 2022The role of iron biomarkers and iron intake in the susceptibility to lung cancer is unclear. The purpose of this study was to conduct a systematic review and... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The role of iron biomarkers and iron intake in the susceptibility to lung cancer is unclear. The purpose of this study was to conduct a systematic review and meta-analysis, to assess the relationship between iron levels in the body or iron intake and the risk of lung cancer.
METHOD
This review is registered with PROSPERO (number CRD 42020199776). PubMed, Web of Science, Scopus, Embase and Cochrane were used to search for studies assessing the relationship between iron and lung cancer, up to July 15, 2021. Qualitative and quantitative analysis was carried out to determine if there was a correlation between iron biomarkers/intakes and the risk of lung cancer.
RESULT
Twenty articles were included. Pooled analyses demonstrated that serum ferritin concentrations and transferrin saturation (TSAT) were significantly higher in patients with lung cancer than in healthy controls (ferritin: standardized mean differences [SMD], 0.235, 95% confidence interval [CI], 0.129, 0.341, I = 32.1 %; TSAT: SMD, 0.07, 95 % CI, 0.018, 0.121, I = 0 %). In contrast, serum transferrin concentrations were significantly lower in patients with lung cancer than in healthy controls (SMD, -0.591, 95 % CI, -1.18, -0.003, I = 87.7 %). No significant effects of serum iron, lung tissue iron, bronchoalveolar lavage fluid (BALF) ferritin, or iron intake (total iron, dietary iron, heme iron, or non-heme iron) were found on lung cancer incidence.
CONCLUSION
Among the different iron biomarkers analyzed, a trend in association was only detected with serum ferritin, TSAT and transferrin concentration and no associations were found between iron intakes and the risk of lung cancer. However, more prospective studies are needed to strengthen the current evidence.
Topics: Biomarkers; Ferritins; Humans; Iron; Iron, Dietary; Lung; Lung Neoplasms; Transferrin
PubMed: 35987180
DOI: 10.1016/j.jtemb.2022.127060 -
BMJ Open Jul 2015To obtain a pooled risk estimate on the long-term impact of anaemia and related nutritional deficiencies in patients receiving Roux-en-Y gastric bypass (RYGB) surgery. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To obtain a pooled risk estimate on the long-term impact of anaemia and related nutritional deficiencies in patients receiving Roux-en-Y gastric bypass (RYGB) surgery.
DESIGN
Systematic review and meta-analysis.
DATA SOURCES
MEDLINE, EMBASE and Cochrane databases were searched to identify English reports published before 16 May 2014.
ELIGIBILITY CRITERIA
Articles with case numbers >100, follow-up period >12 months, and complete data from both before and after surgery were selected. Outcomes of interest were changes in baseline measurements of proportion of patients with anaemia, by haemoglobin, haematocrit, ferritin, iron, vitamin B12 and folate levels.
DATA COLLECTION AND ANALYSIS
Two reviewers independently reviewed data and selected six prospective and nine retrospective studies with a total of 5909 patients. A random effect model with inverse variance weighting was used to calculate summary estimates of outcomes at 6, 12, 24 and 36 months postoperatively.
RESULTS
Proportion of patients with anaemia was 12.2% at baseline, which, respectively, increased to 20.9% and 25.9% at 12 and 24 months follow-up, consistent with decreases in haemoglobin and haematocrit levels. Although the serum iron level did not change substantially after surgery, the frequency of patients with ferritin deficiency increased from 7.9% at baseline to 13.4% and 23.0% at 12 and 24 months, respectively, postoperation. Vitamin B12 deficiency increased from 2.3% at baseline to 6.5% at 12 months after surgery in those subjects receiving RYGB. There was no obvious increase in folate deficiency.
CONCLUSIONS
RYGB surgery is associated with an increased risk of anaemia and deficiencies of iron and vitamin B12, but not folate. Ferritin is more sensitive when serum iron level is within normal range.
Topics: Anemia; Ferritins; Gastric Bypass; Humans; Iron; Obesity, Morbid; Postoperative Period; Vitamin B 12 Deficiency
PubMed: 26185175
DOI: 10.1136/bmjopen-2014-006964 -
Medicine Jan 2016Biological and epidemiological evidence have found that gestational diabetes mellitus (GDM) may be correlated with body iron status and dietary iron intake. Therefore,... (Meta-Analysis)
Meta-Analysis Review
Biological and epidemiological evidence have found that gestational diabetes mellitus (GDM) may be correlated with body iron status and dietary iron intake. Therefore, we investigated the relationship between dietary iron intake and body iron status and GDM risk.We conducted a systematic search in Embase, PubMed, Web of Science, and Cochrane Library up to April 2015. Prospective cohort studies or case-control studies which appraised the relationship between body iron status, dietary iron intake, and GDM risk were included. Relative risks (RRs), standard mean difference (SMD), and 95% confidence intervals [CIs] were used to measure the pooled data.A total of 8 prospective cohort studies and 7 case-control studies were in accordance with inclusive criteria, and 14 studies were included in meta-analysis. The overall RR comparing the highest and lowest levels of serum ferritin was 3.22 (95% CI: 1.73-6.00) for prospective cohort studies. Serum ferritin of GDM group is markedly higher than that of control (0.88 ng/mL; 95% CI: 0.40-1.35 ng/mL) for case-control studies. The comparison between the highest and the lowest serum ferritin levels and dietary total iron levels revealed pooled RRs of 1.53 (95% CI: 1.17-2.00) and 1.01 (95% CI: 1.00-1.01) for prospective cohort studies, respectively. The combined SMD comparing serum transferrin levels of cases and controls was -0.02 μmol/L (95% CI: -0.22 to 0.19 μmol/L) for case-control studies.Increased higher ferritin levels were significantly correlated with higher risk of GDM, and higher heme iron levels may be correlated with higher risk of GDM; however, the present conclusion did not constitute definitive proof that dietary total iron or serum transferrin have relation to GDM.
Topics: Diabetes, Gestational; Female; Ferritins; Humans; Iron; Iron, Dietary; Pregnancy
PubMed: 26765415
DOI: 10.1097/MD.0000000000002383 -
Atherosclerosis Feb 2015Observations in the past have hypothesized an association between body iron status and coronary heart disease (CHD). Epidemiological studies to date have however been... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Observations in the past have hypothesized an association between body iron status and coronary heart disease (CHD). Epidemiological studies to date have however been inconclusive without the existence of strongly positive or strongly negative associations between iron status and coronary heart disease.
OBJECTIVES
To investigate the association between iron status and coronary heart disease.
DATA SOURCES
A systematic review was performed using the databases PubMed and Cochrane Library. Search terms included iron, ferritin, transferrin, total iron binding capacity, coronary heart disease and angina.
STUDY SELECTION
Only prospective studies investigating the association of body iron status and coronary heart disease were included. All participants were free from coronary heart disease at baseline. There were no language or geographic restrictions imposed on the search strategy.
DATA EXTRACTION
Independent extraction of articles by 2 authors using predefined data fields.
DATA SYNTHESIS
All pooled analyses were based on random-effects models. A total of 17 studies were identified for analysis, involving a total of 9236 cases of coronary heart disease and 156,427 participants. Several studies reported more than 1 marker of iron status. For serum ferritin, comparison of individuals in the top third versus the bottom third of baseline measurements yielded a combined risk ratio of 1.03 (95%CI, 0.87-1.23) for CHD/MI. For transferrin saturation, the combined risk ratio for CHD/MI was 0.82 (95% CI, 0.75-0.89) for individuals in the top third versus the bottom third of baseline measurements. Comparison of individuals in top and bottom thirds of baseline measurements yielded non-significant risk ratios of studies involving total iron-binding capacity (combined risk ratio, 0.99; 95% CI 0.86-1.13) and serum iron (combined risk ratio, 0.87; 95% CI 0.73-1.04). For serum iron, the combined risk ratio for CHD/MI after excluding the study by Morrisson et al. [1] was 0.80 (95% CI, 0.73-0.87).
CONCLUSIONS
The results suggest that there is a negative association of transferrin levels and coronary heart disease with high transferrin saturations being associated with a lower risk of CHD/MI. There was also a negative association of serum iron and CHD/MI after one study [1] was excluded. There is no significant association between the other markers of iron status and CHD. It is however difficult to infer causality from these findings due to limitations in terms of reverse causality bias and residual confounding.
Topics: Biomarkers; Coronary Disease; Ferritins; Humans; Iron; Odds Ratio; Prognosis; Prospective Studies; Protective Factors; Risk Factors; Transferrin
PubMed: 25544180
DOI: 10.1016/j.atherosclerosis.2014.12.018 -
Systematic Reviews Jan 2024Intravenous iron (IV-iron) is used as an alternative to, or alongside, red blood cell transfusion (RBC-T) to treat more severe postpartum anemia (PPA), although optimal... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Intravenous iron (IV-iron) is used as an alternative to, or alongside, red blood cell transfusion (RBC-T) to treat more severe postpartum anemia (PPA), although optimal treatment options remain unclear. No previous systematic reviews have examined IV-iron and RBC-T, including patient-reported outcomes and hematological responses.
METHODS
A systematic review and meta-analysis of randomized trials comparing IV-iron and RBC-T with each other, oral iron, no treatment, and placebo for the treatment of PPA. Key inclusion criteria were PPA (hemoglobin < 12 g/dL) and IV-iron or RBC-T as interventions. Key exclusion criteria were antenatal IV-iron or RBC-T. Fatigue was the primary outcome. Secondary outcomes included hemoglobin and ferritin concentrations, and adverse events. From 27th August 2020 to 26th September 2022, databases, registries, and hand searches identified studies. A fixed-effect meta-analysis was undertaken using RevMan (5.4) software. The quality of the studies and the evidence was assessed using the Cochrane Risk of Bias table, and Grading of Recommendations, Assessment, Development, and Evaluation. This review is registered with the Prospective Register of Systematic Reviews (CRD42020201115).
RESULTS
Twenty studies and 4196 participants were included: 1834 assigned IV-iron, 1771 assigned oral iron, 330 assigned RBC-T, and 261 assigned non-intervention. Six studies reported the primary outcome of fatigue (1251 participants). Only studies of IV-iron vs. oral iron (15 studies) were available for meta-analysis. Of these, three reported on fatigue using different scales; two were available for meta-analysis. There was a significant reduction in fatigue with IV-iron compared to oral iron (standardized mean difference - 0.40, 95% confidence interval (CI) - 0.62, - 0.18, I = 0%). The direction of effect also favored IV-iron for hemoglobin (mean difference (MD) 0.54 g/dL, 95% confidence interval (CI) 0.47, 0.61, I = 91%), ferritin, (MD 58.07 mcg/L, 95% CI 55.74, 60.41, I = 99%), and total adverse events (risk-ratio 0.63, 95% CI 0.52, 0.77, I = 84%). The overall quality of the evidence was low-moderate.
DISCUSSION
For all outcomes, the evidence for RBC-T, compared to IV-iron, non-intervention, or dose effects of RBC-T is very limited. Further research is needed to determine whether RBC-T or IV-iron for the treatment of PPA is superior for fatigue and hematological outcomes.
Topics: Female; Humans; Pregnancy; Iron; Anemia; Blood Transfusion; Hemoglobins; Ferritins; Postpartum Period; Fatigue
PubMed: 38169415
DOI: 10.1186/s13643-023-02400-4 -
The Cochrane Database of Systematic... Jan 2019Anaemia is a condition in which the number of red blood cells is insufficient to meet physiologic needs; it is caused by many conditions, particularly iron deficiency.... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Anaemia is a condition in which the number of red blood cells is insufficient to meet physiologic needs; it is caused by many conditions, particularly iron deficiency. Traditionally, daily iron supplementation has been a standard practice for preventing and treating anaemia. However, its long-term use has been limited, as it has been associated with adverse side effects such as nausea, constipation, and teeth staining. Intermittent iron supplementation has been suggested as an effective and safer alternative to daily iron supplementation for preventing and reducing anaemia at the population level, especially in areas where this condition is highly prevalent.
OBJECTIVES
To assess the effects of intermittent oral iron supplementation, alone or in combination with other nutrients, on anaemia and its associated impairments among menstruating women, compared with no intervention, a placebo, or daily supplementation.
SEARCH METHODS
In February 2018, we searched CENTRAL, MEDLINE, Embase, nine other databases, and two trials registers. In March 2018, we also searched LILACS, IBECS and IMBIOMED. In addition, we examined reference lists, and contacted authors and known experts to identify additional studies.
SELECTION CRITERIA
Randomised controlled trials (RCTs) and quasi-RCTs with either individual or cluster randomisation. Participants were menstruating women; that is, women beyond menarche and prior to menopause who were not pregnant or lactating and did not have a known condition that impeded the presence of menstrual periods. The intervention was the use of iron supplements intermittently (one, two or three times a week on non-consecutive days) compared with placebo, no intervention, or the same supplements provided on a daily basis.
DATA COLLECTION AND ANALYSIS
Both review authors independently assessed the eligibility of studies against the inclusion criteria, extracted data from included studies, checked data entry for accuracy, assessed the risk of bias of the included studies, and rated the quality of the evidence using GRADE.
MAIN RESULTS
We included 25 studies involving 10,996 women. Study methods were not well described in many of the included studies and thus assessing risk of bias was difficult. The main limitations of the studies were lack of blinding and high attrition. Studies were mainly funded by international organisations, universities, and ministries of health within the countries. Approximately one third of the included studies did not provide a funding source.Although quality across studies was variable, the results consistently showed that intermittent iron supplementation (alone or with any other vitamins and minerals) compared with no intervention or a placebo, reduced the risk of having anaemia (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.49 to 0.87; 11 studies, 3135 participants; low-quality evidence), and improved the concentration of haemoglobin (mean difference (MD) 5.19 g/L, 95% CI 3.07 to 7.32; 15 studies, 2886 participants; moderate-quality evidence), and ferritin (MD 7.46 μg/L, 95% CI 5.02 to 9.90; 7 studies, 1067 participants; low-quality evidence). Intermittent regimens may also reduce the risk of having iron deficiency (RR 0.50, 95% CI 0.24 to 1.04; 3 studies, 624 participants; low-quality evidence), but evidence was inconclusive regarding iron deficiency anaemia (RR 0.07, 95% CI 0.00 to 1.16; 1 study, 97 participants; very low-quality evidence) and all-cause morbidity (RR 1.12, 95% CI 0.82 to 1.52; 1 study, 119 participants; very low-quality evidence). Women in the control group were less likely to have any adverse side effects than those receiving intermittent iron supplements (RR 1.98, 95% CI 0.31 to 12.72; 3 studies, 630 participants; moderate-quality evidence).In comparison with daily supplementation, results showed that intermittent supplementation (alone or with any other vitamins and minerals) produced similar effects to daily supplementation (alone or with any other vitamins and minerals) on anaemia (RR 1.09, 95% CI 0.93 to 1.29; 8 studies, 1749 participants; moderate-quality evidence). Intermittent supplementation may produce similar haemoglobin concentrations (MD 0.43 g/L, 95% CI -1.44 to 2.31; 10 studies, 2127 participants; low-quality evidence) but lower ferritin concentrations on average (MD -6.07 μg/L, 95% CI -10.66 to -1.48; 4 studies, 988 participants; low-quality evidence) compared to daily supplementation. Compared to daily regimens, intermittent regimens may also reduce the risk of having iron deficiency (RR 4.30, 95% CI 0.56 to 33.20; 1 study, 198 participants; very low-quality evidence). Women receiving iron supplements intermittently were less likely to have any adverse side effects than those receiving iron supplements daily (RR 0.41, 95% CI 0.21 to 0.82; 6 studies, 1166 participants; moderate-quality evidence). No studies reported on the effect of intermittent regimens versus daily regimens on iron deficiency anaemia and all-cause morbidity.Information on disease outcomes, adherence, economic productivity, and work performance was scarce, and evidence about the effects of intermittent supplementation on these outcomes unclear.Overall, whether the supplements were given once or twice weekly, for less or more than three months, contained less or more than 60 mg of elemental iron per week, or given to populations with different degrees of anaemia at baseline did not seem to affect the findings. Furthermore, the response did not differ in areas where malaria was frequent, although very few trials were conducted in these settings.
AUTHORS' CONCLUSIONS
Intermittent iron supplementation may reduce anaemia and may improve iron stores among menstruating women in populations with different anaemia and malaria backgrounds. In comparison with daily supplementation, the provision of iron supplements intermittently is probably as effective in preventing or controlling anaemia. More information is needed on morbidity (including malaria outcomes), side effects, work performance, economic productivity, depression, and adherence to the intervention. The quality of this evidence base ranged from very low to moderate quality, suggesting that we are uncertain about these effects.
Topics: Administration, Oral; Adolescent; Adult; Anemia, Iron-Deficiency; Dietary Supplements; Drug Administration Schedule; Female; Ferritins; Ferrous Compounds; Humans; Iron Deficiencies; Iron, Dietary; Menstruation; Micronutrients; Randomized Controlled Trials as Topic; Young Adult
PubMed: 30699468
DOI: 10.1002/14651858.CD009218.pub3