Adherence to the Mediterranean diet can beneficially affect the gut microbiota composition: a systematic review

AIM

Dietary patterns could have a notable role in shaping gut microbiota composition. Evidence confirms the positive impact of the Mediterranean diet (MD), as one of the most studied healthy dietary patterns, on the gut microbiota profile. We conducted this systematic review to investigate the results of observational studies and clinical trials regarding the possible changes in the gut microbiota composition, metabolites, and clinical outcomes following adherence to MD in healthy cases or patients suffering from metabolic disorders.

METHODS

A systematic literature search was conducted on PubMed, Web of Science, and Scopus databases until October 2023. Two researchers separately screened the titles, abstracts, and then full-text of the articles and selected the relevant studies. Quality assessment of observational and interventional studies was performed by Newcastle-Ottawa and Cochrane checklists, respectively.

RESULTS

A total of 1637 articles were obtained during the initial search. Ultimately, 37 articles, including 17 observational and 20 interventional studies, were included in this systematic review. Ten observational and 14 interventional studies reported a correlation between MD adherence and microbiota diversity. Faecalibacterium and Prevotella were the most frequent bacterial genera with increased abundance in both observational and interventional studies; an Increment of Bacteroides genus was also reported in observational studies. Better glycemic control, lowering fat mass, better bowel movement, decreased bloating, inflammation, and hospitalization risk were the reported clinical outcomes.

CONCLUSION

Adherence to the MD is associated with significant beneficial changes in the gut microbiota diversity, composition, and functions and major clinical improvements in most populations.

The association of infant and mother gut microbiomes with development of allergic diseases in children: a systematic review

OBJECTIVE

It is believed that gut microbiota alteration leads to both intestinal and non-intestinal diseases in children. Since infants inherit maternal microbiota during pregnancy and lactation, recent studies suggest that changes in maternal microbiota can cause immune disorders as well. This systematic review was designed to assess the association between the child and mother's gut microbiome and allergy development in childhood.

DATA SOURCES

In this systematic review, international databases including PubMed, Scopus, and ISI/WOS were searched until January 2023 to identify relevant studies.

STUDY SELECTIONS

Observational studies that analyzed infant or maternal stool microbiome and their association with allergy development in children were included in this study. Data extraction and quality assessment of the included studies were independently conducted by two researchers.

RESULTS

Of the 1694 papers evaluated, 21 studies examined neonate gut microbiome by analyzing stool samples and six studies examined maternal gut microbiota. A total of 5319 participants were included in this study. Asthma followed by eczema and dermatitis were the most common allergy disorders among children. Urbanization caused a lack of diversity in the bacterial microbiota as well as lower levels of Bifidobacterium and Lachnospira associated with a higher risk of allergy. In contrast, higher levels of Roseburia and Flavonifractor were associated with lower allergy risk.

CONCLUSIONS

This systematic review shows that gut microbiota may be associated with allergy development. Further studies are required to provide a definitive answer.

The impact of vegetarian diet on sperm quality, sex hormone levels and fertility: a systematic review and meta-analysis

BACKGROUND

An increasing number of people have adhered to a vegetarian diet for several years. Nowadays, the favourable effect of this dietary pattern on metabolic diseases is well established, but its impact on fertility and reproductive health as a serious health concern is not clear yet. Therefore, we aim to summarise existing evidence regarding the possible association between a vegetarian diet and fertility as measured by key indicators such as sperm quality and sex hormone levels.

METHODS

We systematically searched online databases, including PubMed, ISI, Scopus and Google Scholar, up to 1 December 2022 using relevant keywords. We included observational studies that compared semen quality, sex hormone levels and infertility in people who adhered to a vegetarian diet versus an omnivore diet. Heterogeneity between studies was assessed using I2 and Q tests. Standardised mean differences (SMD) using a random/fixed model were calculated to assess outcomes between vegetarians and omnivores in included articles.

RESULTS

Finally, out of 972 documents that were retrieved, 20 articles met our inclusion criteria, and 16 were eligible for quantitative synthesis. Results of meta-analyses showed that there were no significant differences between vegetarians and omnivores in terms of semen quality parameters, including total sperm count, total and progressive sperm motility, sperm morphology and sperm concentration. Seven studies on female sex hormone profiles were eligible for meta-analysis. The only significant difference was the lower level of plasma oestrone in vegetarians (pooled SMD: -0.56; 95% confidence interval [CI]: -1.08, -0.05; p-value = 0.03) compared to omnivores. Furthermore, our meta-analysis revealed significantly higher sex-hormone-binding globulin levels in vegetarian men than in omnivores (pooled SMD: 0.52; 95% CI: 0.18, 0.86; p-value = 0.002).

CONCLUSION

Despite the numerous health benefits of a vegetarian diet, our review suggested that there were no conclusive positive or negative associations between vegetarian diet and semen quality, sex hormone levels and infertility. Further studies are recommended to better understand vegetarian dietary pattern effect on infertility and reproductive health.

The Effect of Fecal Microbiota Transplantation on Cardiometabolic Risk Factors: A Systematic Review and Meta-Analysis

PURPOSE

Cardiometabolic disease (CMD) is increasing along with its predisposing factors and adverse consequences. As gut microbiota dysbiosis is established in these patients, fecal microbiota transplantation (FMT), which alters the bacterial composition of the intestine, supposedly can help improve cardiometabolic disturbances. We conducted a systematic review and meta-analysis evaluating the impact of FMT on the cardiometabolic parameters and gut microbiota composition of patients experiencing at least one cardiometabolic issue.

METHODS

Eligible studies were searched through the PubMed, Web of Science, and Scopus databases until December 2022. The initial search results underwent duplication removal and screening until each included study was scanned for intended data. The Cochrane risk of bias tool was used to evaluate the methodologic accuracy of studies and the random effects model was used for conducting the meta-analysis.

FINDINGS

Eighteen of the original 2414 articles from the literature search were entered into the systematic review; of these, 11 were included in the meta-analysis. Insulin showed a significant decrease by 24.7 pmol/L (weighted mean difference [WMD], -24.77; 95% CI, -48.704 to -0.848) after short-term follow-up, and HDL increased by 0.1 mmol/l(WMD, 0.106; 95% CI, 0.027 to 0.184) and 0.12 mmol/l(WMD, 0.120; 95% CI, 0.003 to 0.237) in those using a capsule deliver mode and in short-term follow-up, respectively. No significant changes were seen in other lipid profiles, blood glucose, insulin resistance, or anthropometric indices. In addition, multiple studies reported gut microbiota alterations after the intervention, including an increase in butyrate-producing species.

IMPLICATIONS

Although some articles reported the beneficial effects of FMT on metabolic parameters, we failed to find a clinically significant alteration. Also, information regarding proper donors and the best method to induce FMT have not yet been sufficiently investigated, which should be considered along with means to prevent potential damages. PROSPERO identifier: CRD42022380705.

Association between Gut Microbiota Compositions with Microvascular Complications in Individuals with Diabetes: A Systematic Review

BACKGROUND

Diabetes is one of the chronic and very complex diseases that can lead to microvascular complications. Recent evidence demonstrates that dysbiosis of the microbiota composition might result in low-grade, local, and systemic inflammation, which contributes directly to the development of diabetes mellitus and its microvascular consequences.

OBJECTIVE

The aim of this systematic review was to investigate the association between diabetes microvascular complications, including retinopathy, neuropathy, nephropathy, and gut microbiota composition.

METHODS

A systematic search was carried out in PubMed, Scopus, and ISI Web of Science from database inception to March 2023. Screening, data extraction, and quality assessment were performed by two independent authors. The Newcastle-Ottawa Quality Assessment Scale was used for quality assessment.

RESULTS

About 19 articles were selected from 590 retrieved articles. Among the included studies, nephropathy has been studied more than other complications of diabetes, showing that the composition of the healthy microbiota is changed, and large quantities of uremic solutes that cause kidney injury are produced by gut microbes. Phyla, including Fusobacteria and Proteobacteria, accounted for the majority of the variation in gut microbiota between Type 2 diabetic patients with and without neuropathy. In cases with retinopathy, an increase in pathogenic and proinflammatory bacteria was observed.

CONCLUSION

Our results revealed that increases in Bacteroidetes, proteobacteria and fusobacteria may be associated with the pathogenesis of diabetic nephropathy, neuropathy, and retinopathy. In view of the detrimental role of intestinal dysbiosis in the development of diabetes-related complications, gut microbiota assessment may be used as a biomarker in the future and interventions that modulate the composition of microbiota in individuals with diabetes can be used to prevent and control these complications.

Dietary fiber intake and all-cause and cause-specific mortality: An updated systematic review and meta-analysis of prospective cohort studies

BACKGROUND

Accumulating evidence supports the effects of dietary fiber on the risk of non-communicable diseases (NCDs). However, there is no updated systematic review and meta-analysis that compares and pools the effect of different types of fiber on mortality.

METHODS

In this systematic review and meta-analysis, all prospective cohort studies that evaluated the relationship between dietary fiber intake and all-cause or cause-specific mortality were included. The PubMed, SCOPUS, and Web of Science databases were searched up to October 2022. Data extraction and quality assessment were performed by two researchers independently. Heterogeneity between studies was assessed using Chi-square based test. Random/fixed effect meta-analysis was used to pool the hazard ratios (HR) or relative risks (RR) and 95 % confidence intervals (CI) for the association between different types of fiber and mortality.

RESULTS

This systematic review included 64 eligible studies, with a total sample size of 3512828 subjects, that investigated the association between dietary fiber intake and mortality from all-cause, cardiovascular disease (CVD), and cancer. Random-effect meta-analysis shows that higher consumption of total dietary fiber, significantly decreased the risk of all-cause mortality, CVD-related mortality, and cancer-related mortality by 23, 26 and 22 % (HR:0.77; 95%CI (0.73,0.82), HR:0.74; 95%CI (0.71,0.77) and HR:0.78; 95%CI (0.68,0.87)), respectively. The consumption of insoluble fiber tended to be more effective than soluble fiber intake in reducing the risk of total mortality and mortality due to CVD and cancer. Additionally, dietary fiber from whole grains, cereals, and vegetables was associated with a reduced risk of all-cause mortality, while dietary fiber from nuts and seeds reduced the risk of CVD-related death by 43 % (HR:0.57; 95 % CI (0.38,0.77)).

CONCLUSION

This comprehensive meta-analysis provides additional evidence supporting the protective association between fiber intake and all-cause and cause-specific mortality rates.

Waist to height ratio as a simple tool for predicting mortality: a systematic review and meta-analysis

BACKGROUND

The association of central obesity with higher rates of mortality is not well studied. This study evaluates the association between waist-to-height ratio (WHtR), as a measure of central obesity, with mortality.

METHODS

Documents were retrieved from PubMed, Web of Science, Scopus, and Google Scholar databases until May 2022. Data were extracted from cohort studies reporting effect size (hazard ratio (HR)) regarding the association between WHtR as a continuous (per 1 SD increment) or categorical (highest/lowest) measure and all-cause and cause-specific mortality. Screening of included studies was performed independently by two authors. Moreover, the quality assessment of included studies was performed based on the Newcastle-Ottawa assessment scale. Finally, random effect meta-analysis was performed to pool the data, and the outcomes' certainty level was assess based on the GRADE criteria.

RESULTS

Of the 815 initial studies, 20 were included in the meta-analysis. Random effect meta-analysis showed that in the general population, the all-cause mortality HRs for categorical and continuous measurements of WHtR increased significantly by 23% (HR:1.23; 95% CI: 1.04-1.41) and 16% (HR:1.16; 95% CI: 1.07-1.25), respectively. Moreover, the hazard of cardiovascular (CVD) mortality increased significantly for categorical and continuous measurements of WHtR by 39% (HR:1.39; 95% CI: 1.18-1.59) and 19% (HR:1.19; 95% CI: 1.07-1.31). The quality assessment score of all included studies was high.

CONCLUSIONS

Higher levels of WHtR, indicating central obesity, were associated with an increased hazard of CVD and all-cause mortality. This measure can be used in the clinical setting as a simple tool for predicting mortality.

Association of dietary phytochemical index with cardiometabolic risk factors

Objective(s): Cardio-metabolic risk factors are becoming a global health concern. To address this problem, one of the proposed ways is to focus on phytochemical-rich foods consumption. Therefore, we aimed to summarize the results of observational studies (cohorts, case-control, and cross-sectional) that investigated the association between dietary phytochemical index (PI) as a new index for evaluating phytochemical-rich food intake and various risk factors of cardio-metabolic disorders. Methods: We conducted a comprehensive systematic review through PubMed, Scopus, and Web of Science databases. The literature search was performed up to August 2021 with no publication year restriction on observational studies investigating the association between PI and cardiometabolic risk factors on adults and children. A random-effect meta-analysis was used. Results: Overall, 16 articles (cross-sectional, case-control, cohort) were eligible for this systematic review and 8 studies with 99771 participants were included in the meta-analysis. Random effect meta-analysis showed that adherence to higher dietary PI decrease the odds of abdominal obesity (OR: 0.73, 95% CI: 0.58, 0.88, I2: 84.90), generalized obesity (OR: 0.84, 95% CI: 0.69, 0.98, I2: 68.10), hypertriglyceridemia (OR: 0.81, 95% CI: 0.73, 0.89, I2: 0.00), hypertension (OR: 0.86, 95% CI: 0.73, 0.99, I2: 7.02), and MetS (OR: 0.79, 95% CI: 0.69, 0.88, I2: 84.90). However, results considering the associations between dietary PI with glycemic indices, and low high-density lipoprotein cholesterol (HDL-C) were not significant (p<0.05). Conclusion: Evidence showed adverse associations between dietary PI and some cardio-metabolic risk factors such as obesity, hypertriglyceridemia, hypertension and metabolic syndrome.

General and abdominal obesity trends in the Iranian adult population from 2004 to 2021

Purpose

The prevalence of overweight/obesity and abdominal obesity is increasing worldwide, accompanied by an increase in the incidence of non-communicable diseases. This study aims to determine the trends of Body Mass Index (BMI) and prevalence of overweight/obesity and abdominal obesity changes in Iranian adult population from 2004 to 2021.

Methods

We conducted this study based on the eight national surveys of noncommunicable disease risk factor surveillance (STEPS) from 2004 to 2021 in Iran. We estimated the crude and standardized mean of BMI and prevalence of general and abdominal obesity in these eight STEPS surveys data. Data weighted using post-stratification method and the trends depicted based on the standardized estimates.

Results

Between 2004 and 2021, and based on the standardized estimates, the mean of BMI increased from 25.19 kg/m2 in 2004 to 26.63 kg/m2 in 2021 (P-value for trend = 0.03). The standardized mean of WC increased from 86.38 cm in 2004 to 91.65 cm in 2021 (P-value for trend = 0.38). The standardized prevalence of obesity (class I and II) increased from 14.54% in 2004 to 20.17% in 2021 (P-value for trend = 0.01). The standardized prevalence of obesity class III increased from 0.82% in 2004 to 1.35% in 2021 (P-value for trend = 0.03). The standardized prevalence of abdominal obesity based on the national and international cut-points increased, but the trend was not statistically significant [(National cut-point: 27.53% in 2004 to 40.43% in 2021 (P-value for trend = 0.71)) (International cut-point: 27.58% in 2004 to 41.81% in 2021 (P-value for trend = 0.06))].

Conclusion

The standardized mean of BMI and prevalence of overweight/obesity and abdominal obesity increased among Iranian adults between 2004 and 2021. Because of the negative public and clinical health implications of obesity, health policymakers should develop comprehensive programs to control this increasing trend of weight gain.

Dietary carbohydrate quality index and cardio-metabolic risk factors

Introduction: Improving the quality of diet is known as one of the practical ways to reduce cardio-metabolic risk factors (CMRFs). The carbohydrate quality index (CQI) is a relatively new index to evaluate diet quality. It is calculated based on the ratio of solid carbohydrates to total carbohydrates, dietary fibre intake, glycemic index and the ratio of whole grains to total grains. This systematic review and meta-analysis was designed to investigate the association between dietary CQI and CMRFs. Methods: In this systematic review, some international databases, including Scopus, PubMed, EMBASE, Web of Science, and Google Scholar up to July 2022, were searched according to appropriate keywords. All observational studies with an English full text assessing the association between the dietary CQI and CMRFs were included. Two researchers independently extracted the data and assessed the quality of the articles with the Newcastle-Ottawa Scale. Random/fixed-effect meta-analysis was used to pool standardized mean difference (SMD) as an effect size. Results: 11 studies with a total of 63962 subjects were found to be eligible and included in the qualitative synthesis; only BMI, WC and metabolic syndrome reached the threshold of 3 reports with the same effect size and thus only 5 were included in the meta-analysis. The main finding of the included studies was that there were inverse associations between CQI and CMRFs, mainly obesity, glucose metabolism indices, and blood pressure. In the five studies included in the random effect meta-analysis, the association between CQI and body mass index (SMD: 0.45, 95%CI: -0.12, 1.01), waist circumference (SMD: -0.09, 95%CI: -0.34, 0.15) and metabolic syndrome (SMD: 0.63, 95%CI: -0.01, 1.28) was not statistically significant. Conclusion: Although the qualitative findings support the positive association of CQI with CMRFs, the evidence is insufficient to conclude robust findings. Further observational and interventional studies are needed to clearly elucidate this association.

Oxidative balance score and risk of cancer: a systematic review and meta-analysis of observational studies

BACKGROUND

The oxidative balance score (OBS) has been utilized to assess the overall pro- and antioxidant exposure status in various chronic diseases. The current meta-analysis was carried out to pool the association between OBS and the risk of cancer.

METHODS

We systematically searched the Web of Science, PubMed, Scopus, Embase, and Google Scholar up to August 2023. All observational studies which evaluated the association of OBS with the risk of cancers were included. There was no time of publication or language restrictions. Heterogeneity between studies was assessed using the Chi-square-based Q-test and the I2. A random-effects model meta-analysis was conducted to estimate the pooled effect sizes. Possible sources of heterogeneity were explored by subgroup and meta-regression analysis.

RESULTS

Totally, 15 studies (9 case-control and 6 cohorts) were eligible for meta-analysis. Random effect model meta-analysis of case-control studies showed that higher OBS significantly decreases the odds of cancers (pooled OR: 0.64, 95% CI: 0.54, 0.74). In the cohort studies, the association of OBS with the risk of cancers was not significant (pooled HR: 0.97, 95% CI: 0.80,1.18). The subgroup analysis showed that cancer type and gender were the potential sources of heterogeneity.

CONCLUSION

Our results show an inverse and significant association between higher OBS and odds of colorectal cancers in case-control and cohort studies. In the case of prostate cancer in cohort studies, our results did not align with the hypothesis. Considering the importance of diet and antioxidant balance in the conditions of malignancy, it is suggested to conduct more comprehensive studies with standard measurement methods to obtain conclusive results.

Does the ketogenic diet improve neurological disorders by influencing gut microbiota? A systematic review

BACKGROUND

The aim of this systematic review is to evaluate the changes in gut microbiota (GM) induced by the Ketogenic Diets (KD) as a potential underlying mechanism in the improvement of neurological diseases.

METHODS

A comprehensive search was conducted on three electronic databases, including PubMed/Medline, Web of Science, and Scopus until December 2022. The inclusion criteria were studies that described any changes in GM after consuming KD in neurological patients. Full text of studies such as clinical trials and cohorts were added. The quality assessment of cohort studies was conducted using the Newcastle-Ottawa Quality Assessment Scale and for the clinical trials using the Cochrane Collaboration tool. The search, screening, and data extraction were performed by two researchers independently.

RESULTS

Thirteen studies examining the effects of the KD on the GM in neurological patients were included. Studies have shown that KD improves clinical outcomes by reducing disease severity and recurrence rates. An increase in Proteobacteria phylum, Escherichia, Bacteroides, Prevotella, Faecalibacterium, Lachnospira, Agaricus, and Mrakia genera and a reduction in Firmicutes, and Actinobacteria phyla, Eubacterium, Cronobacter, Saccharomyces, Claviceps, Akkermansia and Dialister genera were reported after KD. Studies showed a reduction in concentrations of fecal short-chain fatty acids and branched-chain fatty acids and an increase in beta Hydroxybutyrate, trimethylamine N-oxide, and N-acetylserotonin levels after KD.

CONCLUSION

The KD prescribed in neurological patients has effectively altered the GM composition and GM-derived metabolites.

Low physical activity and depression are the prominent predictive factors for falling in older adults: the Birjand Longitudinal Aging Study (BLAS)

BACKGROUND

Falling in the older adults has many irreparable consequences, including hospitalization to long-term care centers and loss of independence, depression and social isolation, financial burden, and death. The present study was conducted to estimate the incidence of falls and their associated factors among community-dwelling older adults.

METHODS

This program is a population-based prospective cohort study (≥ 60 years) in Birjand City from 2019 to 2020. A total of 1418 participants were included in the study, and 1344 participants were analyzed according to the inclusion criteria. Thirty-nine risk factors were evaluated. Basic information included demographic information, lifestyle factors, general health and medical history, and mental and functional health.

RESULT

The incidence of falls among community-dwelling older adults in the previous approximately 24 months in the present study was 9.26% in women and 2.65% in men. In the multiple Cox proportional regression model based on fall risk factors, there was a strong significant relationship between male sex (HR = 0.37, CI = 0.21 to 0.64), being physically active (HR = 0.59, CI = 0.36 to 0.96), moderate-to-severe depression (HR = 2.97, CI = 1.47 to 6.01), severe depression (HR = 3.26, CI = 1.24 to 8.54), and high risk of falls according to the TUG test (HR = 1.73, CI = 1.10 to 2.72).

CONCLUSIONS

Inactivity and depression were recognized as important factors in falls in older adults. It is recommended for older adults to have an active lifestyle to prevent falls and to prioritize the diagnosis and treatment of depression in older adults. Women as a group at higher risk should be considered in prevention programs. In addition, the use of the TUG test to identify high-risk older adults should be considered.

Association between childhood obesity and infertility in later life: a systematic review of cohort studies

BACKGROUND

The global prevalence of childhood obesity has exhibited a troubling surge in recent years. Due to the raised questions regarding its potential correlation with infertility in adulthood, this systematic review has been undertaken to explore the relationships between childhood obesity, and infertility later in life.

METHODS

A comprehensive search was performed in three international databases (PubMed, Web of Science, and Scopus). All cohort (retrospective or prospective), case-cohort, and nested case-control studies until April 2022 which assessed the association of obesity in children and adolescents with male and female infertility indicators in later life were included. The quality of the included studies was assessed by Newcastle-Ottawa quality assessment checklists.

RESULT

Out of the initial 32,501 documents, eleven eligible studies with a total sample size of 498,980 participants were included. Five studies focused on the number of offspring and indicated that obesity, especially in adolescence had an association with later life lower number of children, nulliparity, and childlessness in both men and women. Concerning conceiving problems, two studies showed that obesity before age 12 increased the risk of female fertility problems in the future. Two studies reported that obesity in early life raised the risk of impaired female reproductive system such as menstrual or ovulatory problems. As well as females, a study discovered that obesity in men during their 20s was linked to an elevated risk of low sperm motility and poor sperm morphology. Another study has reported men with higher pre-pubertal BMI had lower sex hormone-binding globulin; however, the same association was not seen between childhood BMI and semen quality.

CONCLUSION

The evidence suggests a positive association between childhood obesity with infertility indicators in later life. Childhood weight reduction strategies are suggested to be implemented in societies in order to reduce infertility rates in later life.

The effects of probiotics on gastrointestinal symptoms and microbiota in patients with celiac disease: a systematic review and meta-analysis on clinical trials

Gluten-free diet (GFD) is the most effective method to manage celiac disease (CD). Many patients do not reach the complete symptom alleviation, even by strict GFD. Recent studies have reported inconsistent results regarding the beneficial benefits of taking probiotics. Therefore, we aimed to evaluate the effects of probiotics on gastrointestinal (GI) symptoms and the possible underlying causes in CD and celiac disease autoimmunity (CDA) patients. Databases, including PubMed, Scopus, Embase, Web of Science and Google Scholar, were searched for clinical trials published until July 2022 about assessing the effects of probiotics or synbiotics on CD or CDA patients. We collected data on GI symptoms, CD markers, inflammatory and immune responses, adverse events, and gut microbiota. A random effect meta-analysis was used to estimate the pooled standardized mean difference (SMD) and confidence interval (CI). We screened 7234 articles, of which 14 were included in the qualitative analysis and 5 in the quantitative analysis. Probiotics might alleviate GI symptoms, especially in the highly symptomatic patients, and improve immune response in CD and CDA patients. Results of the meta-analysis showed that probiotics increased the abundance of Bifidobacterium (SMD: 0.72, 95%CI (0.13, 1.30) and Lactobacillus (SMD: 0.49, 95%CI (0.18, 0.80) as compared with placebo. Probiotics did not increase the adverse events compared to the placebo. Probiotics might alleviate GI symptoms and immune response and improve dysbiosis in CD and CDA patients. However, high-quality clinical trials are needed to increase the level of evidence. Also, the most suitable combination of probiotics is yet to find.

Junk food consumption and psychological distress in children and adolescents: a systematic review and meta-analysis

Background: Available evidence indicates that junk foods, defined as unhealthy foods with high-calorie and low-nutrient value, negatively affect mental and metabolic health of children. This study aimed to conduct a meta-analysis to clarify the association between junk food consumption and psychological distress in children and adolescents.Methods: A systematic literature search of relevant documents published in PubMed, Web of Science, and SCOPUS was conducted up to 2022. All observation studies which assessed association of junk foods and psychological distress in children and adolescents were included. Random-effect model was used to pool odds ratio (OR) and 95% confidence interval (CI) from individual studies. Subgroup meta-analysis was performed based on junk foods categories (sweet drinks, sweet snacks and snacks).Results: Data of 17 included articles on junk foods consumption in relation to depression, stress, anxiety, sleep dissatisfaction and happiness in children and adolescents were included in this systematic review. According to random effect model, the pooled OR in the highest vs. the lowest category of junk foods was 1.62 (95% CI: 1.35-1.95) for depression, 1.34 (95% CI: 1.16-1.54) for stress, 1.24 (95% CI: 1.03-1.50) for anxiety, 1.17 (95% CI: 1.05-1.30) for sleep dissatisfaction and 0.83 (95% CI: 0.75-0.92) for happiness. In subgroup meta-analysis, there were significant associations between different types of junk foods and psychological distress (P < 0.05).Conclusion: This meta-analysis showed that junk foods consumption was associated with increased odds of psychological distress in children and adolescents. These findings support the current recommendation of decreasing junk foods intake.

The effects of probiotics, prebiotics, and synbiotics on polycystic ovarian syndrome: an overview of systematic reviews

Introduction

Accumulating evidence has highlighted the critical role of the gut microbiota and its potential action as a regulator of metabolic disorders including insulin resistance, obesity, and systemic inflammation in polycystic ovarian syndrome (PCOS). Microbiota-modulating interventions, such as probiotics, prebiotics, and synbiotics, could be effective in PCOS management.

Methods

We conducted an overview of systematic reviews (SRs) and meta-analyses to summarize reviews regarding the effectiveness of probiotics/prebiotics/synbiotics on the management of PCOS through a systematic literature search in PubMed, Web of Science, and Scopus databases until September 2021.

Results

Eight SRs and meta-analyses were included in this study. Our overview confirmed that probiotic supplementation had a potentially beneficial effect on some PCOS-related parameters including body mass index (BMI), fasting plasma glucose (FPG), and lipid profiles. Evidence shows that synbiotics in comparison with probiotics were less effective on these parameters. The methodological quality of SRs was assessed using the AMSTAR-2 assessment tool and was determined as high for four SRs, low for two SRs, and critically low for one SR. Due to limited evidence and high heterogeneity of the studies, it remains difficult to identify optimal probiotics strains, prebiotics types, length of duration, and doses.

Discussion

Future clinical trials with higher quality are recommended to clarify the efficacy of probiotics/prebiotics/synbiotics on the management of PCOS and provide more accurate evidence.

The association between vitamin D status and sleep duration in school-aged children; the CASPIAN-V study

Background

Considering the high prevalence of both vitamin D deficiency (VDD) and sleep impairment in children and adolescents, this study was conducted to determine the association between VDD and sleep duration in the Iranian pediatric population.

Methods

This multicentric national study was conducted in 2019 on 2564 frozen sera obtained from 7 to 18- year students who were studied in the fifth survey of a national school-based surveillance program conducted in 30 provinces of Iran. Sleep duration was assessed using a questionnaire based on the World Health Organization-Global School-based Student Health Survey protocol. Short sleep duration was defined as sleep duration less than 8 h/day VDD Vitamin D < 20 ng/dL, and vitamin D insufficiency as 20-30 ng/dL.An adjusted logistic regression model was applied to evaluate the associations of vitamin D status with sleep duration.

Results

The Mean (SD) of students' age was 12.1(3.0) years; overall 10.6%of participants had VDD and 23% of participants had short sleep duration. in the adjusted logistic model, students with a low level of vitamin D (insufficient and deficient) had a higher odds of short sleep duration in comparison to those with normal vitamin D level (OR: 1.29, 95%CI: 1.02-1.62).

Conclusion

The current study showed that low Vitamin D levels (insufficient and deficient)were significantly associated with short sleep duration in school-aged children. Further studies are recommended to determine the efficacy of vitamin D replacement in improving sleep duration and quality.

Exploring the role of gut microbiota dysbiosis in gout pathogenesis: a systematic review

Objectives

Gut dysbiosis is believed to be one of the several mechanisms that are involved in the pathogenesis of gout. This systematic review aimed to summarize the role of gut dysbiosis in gout disease and uncover the underlying mechanisms.

Methods

A comprehensive search was conducted on PubMed, Web of Science, and Scopus databases up to October 2021. Animal studies and human observational studies, including case-control, cross-sectional, and cohort studies assessing the association between gut microbiota composition and gout were included. The quality of included studies has been evaluated using the Newcastle-Ottawa Quality Assessment scale (NOS) and the SYRCLE's risk of bias tool.

Results

Initially, we found 274 studies among which 15 studies were included in this systematic review. Of them, 10 studies were conducted on humans and 5 studies were conducted on animals. Increased abundance of Alistipes and decreased abundance of Enterobacteriaceae alters purine metabolism, thereby aggravating gout condition. Moreover, a higher abundance of Phascolarctobacterium and Bacteroides in gout modulates enzymatic activity in purine metabolism. Butyrate-producing bacteria such as Faecalibacterium, prausnitzii, Oscillibacter, Butyricicoccus, and Bifidobacterium have higher abundance in healthy controls compared to gout patients, suggesting the anti-inflammatory and anti-microbial role of short-chain fatty acids (SCFAs). Lipopolysaccharides (LPS)-releasing bacteria, such as Enterobacteriaceae, Prevotella, and Bacteroides, are also involved in the pathogenesis of gout disease by stimulating the innate immune system.

Conclusion

Exploring the role of gut dysbiosis in gout and the underlying mechanisms can help develop microbiota-modulating therapies for gout.

Association between Childhood Obesity and Later Life Kidney Disorders: A Systematic Review

BACKGROUND

Childhood obesity is considered one of the important risk factors for many long-term morbidities. However, the long-term consequences of childhood obesity on kidney function are largely unknown. This systematic review was designed to sum up evidences for the long-term consequences of childhood obesity on kidney function in midlife.

METHODS

In this systematic review, all prospective or retrospective cohort studies and nested case-control articles were searched via some international databases including PubMed, Scopus, Web of Science and Google Scholar using appropriate keywords until July 2022. All studies that were available in English which assessed the association of childhood and adolescence obesity with the occurrence of kidney diseases in later life were included. Studies which assessed the childhood obesity based on self-report weight status were excluded. Data extraction and quality assessment of the included studies was performed by two independent researchers.

RESULTS

Finally after screening 6843 published articles, 8 prospective cohorts studies were included in the qualitative synthesis. All the included studies were published in the last ten years. The overall follow-up duration of studies ranged from 8 to 64 years. Out of eight included studies, six reported a statistically significant positive association between higher BMI levels in early life and greater renal disease risk in later lifkidney diseases and kidney damage related morbidity were appraised as the outcome in six of the included observational studies (highest HR:6.89), and kidney related mortality was reported in one study (HR: 8.4) among cases that were obese in adolescence.

CONCLUSION

Evidence from various populations implicate s a positive link between obesity in early life and kidney disease in later life. This fact may cause motivation among public health executives to establish policies for more serious population-based obesity prevention.

The Effect of a Moderately Restricted Carbohydrate Diet on Cardiometabolic Risk Factors in Overweight and Obese Women With Metabolic Syndrome: A Randomized Controlled Trial

PURPOSE

Metabolic syndrome (MetS) is a major public health concern that increases the risk of cardiovascular disease and mortality. In previous studies of MetS management, low-carbohydrate diets have been strongly emphasized, despite the fact that many apparently healthy individuals have difficulties adhering to these diets on a long-term basis. The purpose of the present study was to elucidate the effects of a moderately restricted carbohydrate diet (MRCD) on cardiometabolic risk factors in women with MetS.

METHODS

This parallel 3-month, single-blind randomized controlled trial was conducted in Tehran, Iran, among 70 women with overweight or obesity aged 20 to 50 years with MetS. Patients were randomly allocated to receive either MRCD (42%-45% carbohydrates and 35%-40% fats) (n = 35) or a normal weight loss diet (NWLD) (52%-55% carbohydrates and 25%-30% fats) (n = 35). Both diets contained the same quantity of protein, which accounted for 15% to 17% of total energy. Anthropometric measurements, blood pressure, lipid profile, and glycemic indices were all assessed before and after the intervention.

FINDINGS

Compared with the NWLD group, following an MRCD significantly decreased weight (-4.82 vs -2.40 kg; P = 0.01), body mass index (-1.88 vs -0.94 kg/m²; P = 0.01), waist circumference (-5.34 vs -2.75 cm; P = 0.01), hip circumference (-2.58 vs -1.11 cm; P = 0.01), serum triglyceride (-26.8 vs -7.19 mg/dL; P = 0.01), and increased serum HDL-C levels (1.89 vs. 0.24 mg/dL; P = 0.01). There was no significant difference between the 2 diets in waist-to-hip ratio, serum total cholesterol, serum LDL-C, systolic and diastolic blood pressure, fasting blood glucose, insulin levels, or the homeostasis model assessment for insulin resistance.

IMPLICATIONS

Moderate carbohydrate replacement with dietary fats significantly improved weight, body mass index, waist circumference, hip circumference, serum triglyceride, and HDL-C levels among women with MetS. Iranian Registry of Clinical Trials identifier: IRCT20210307050621N1.

The critical role of gut microbiota dysbiosis in skeletal muscle wasting: a systematic review

AIMS

Skeletal muscle wasting is affected by the gut microbiota dysbiosis through multiple pathways, including inflammatory process, defected immune system, and anabolic resistance. We aimed to systematically review the studies investigating the gut microbiota composition in sarcopenic and cachexic humans and animals.

METHODS

We carried out a comprehensively systematic search using relevant keywords on PubMed, Web of Science, and Scopus databases until July 2021. Original human observational research and animal studies related to our research topics published in English were selected.

RESULTS

Seven human studies and five animal studies were included. Three human studies were case-control, whereas the other four were cross-sectional studies that investigated three different conditions, including age-related sarcopenia, as well as liver cirrhosis and cancer cachexia. The principal alteration in age-related sarcopenia and liver cirrhosis-induced sarcopenia was a reduction in short-chain fatty acids (SCFAs) -producing bacteria. Lachnospiraceae family, consisting of Lachnospira, Fusicatenibacter, Roseburia, and Lachnoclostridium, significantly decreased in age-related sarcopenia, while in liver cirrhosis-induced sarcopenia, the alpha diversity of gut microbiota decreased compared with the control group. Moreover, Enterobacteriaceae, which has a pro-inflammatory effect increased in muscle-wasted animals.

CONCLUSION

This systematic review presents associations between the gut microbiota alterations and skeletal muscle wasting as a consequence of various pathologies, including aging sarcopenia, renal failure, and cancer cachexia in both human and animal studies.

Optimal cut-off value of waist circumference-to-height ratio to predict central obesity in children and adolescents: A systematic review and meta-analysis of diagnostic studies

Introduction

Waist circumference-to-height ratio (WHtR) is a simple anthropometric index with good screening power and fast interpretation for early detection of childhood abdominal obesity. This systematic review and meta-analysis aims to determine the best cut-off value of WHtR to use in clinical setting.

Methods

Comprehensive searches were conducted in PubMed, Scopus, and Web of Science by the end of March 2021. Observational studies investigated the best WHtR cut-off to detect abdominal obesity in children and adolescents were included. Thirteen articles (n = 180,119) were included in this systematic review and eight documents were included in the meta-analysis.

Results

The overall optimal cut-off was 0.49 with pooled sensitivity, specificity and diagnostic odds ratio (DOR) of 0.93 (95% confidence interval (CI): 0.93-0.96), 0.88 (95% CI: 0.85-0.91) and 102.6 (95% CI: 50.7-207.5), respectively. The optimal WHtR cut-off to predict abdominal obesity in girls and boys were both 0.49.

Discussion

The current study shows that we could use this cut-off as a simple index for predicting abdominal obesity in children and adolescents without the need for any charts in practice.

Antioxidative hypoglycemic herbal medicines with in vivo and in vitro activity against C-reactive protein; a systematic review

BACKGROUND

Inflammation is a double-edged sword in the pathophysiology of chronic diseases, such as type 2 diabetes mellitus (T2DM). The global rise in the prevalence of T2DM in one hand, and poor disease control with currently-available treatments on the other hand, along with an increased tendency towards the use of natural products make scientists seek herbal medicines for the management of diabetes and its complications by reducing C-reactive protein (CRP) as an inflammatory marker.

PURPOSE

To systematically review the literature to identify the efficacy of various medicinal plants with antioxidative and anti-inflammatory properties considering their effect on CRP in animal models of T2DM.

STUDY DESIGN

systematic review.

METHODS

Electronic databases including PubMed, Scopus, Web of Science and Cochran Library were searched using the search terms "herbal medicine", "diabetes", "c-reactive protein", "antioxidants" till August 2021. The quality of evidence was assessed using the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE's) tool. The study protocol was registered in PROSPERO with an ID number CRD42020207190. A manual search to detect any articles not found in the databases was also made. The identified studies were then critically reviewed and relevant data were extracted and summarized.

RESULTS

Among total of 9904 primarily-retrieved articles, twenty-three experimental studies were finally included. Our data indicated that numerous herbal medicines, compared to placebo or hypoglycemic medications, are effective in treatment of diabetes and its complications through decreasing CRP concentrations and oxidative stresses levels. Medicinal plants including Psidium guajava L., Punica granatum L., Ginkgo biloba L., Punica granatum L., Dianthus superbusn L.. Moreover, Eichhornia crassipes (Mart.) Solms, Curcuma longa L., Azadirachta indica A. Juss., Morus alba L., and Ficus racemosa L. demonstrated potential neuroprotective effects in animal models of diabetes.

CONCLUSION

Hypoglycemic medicinal plants discussed in this review seem to be promising regulators of CRP, and oxidative stress. Thus, these plants are suitable candidates for management of diabetes' complications. Nevertheless, further high-quality in vivo studies and clinical trials are required to confirm these effects.

Association of fat mass and obesity-associated (FTO) gene polymorphisms with non-communicable diseases (NCDs) in the Iranian population: A systematic review of observational studies

Background

Single nucleotide polymorphisms have been implicated in various diseases, most notably non-communicable diseases (NCDs). The aim of this study was to review available evidence regarding associations between FTO polymorphisms and NCDs in the Iranian population.

Methods

A comprehensive search was conducted through PubMed/Medline and Scopus databases up to December 2021, as well as reference lists of pertinent articles and key journals. All observational studies that examined the association between FTO gene polymorphisms and NCDs in the Iranian population were included. There was no limitation on the publication year. The Newcastle-Ottawa Scale (NOS) was used to assess the study's quality.

Results

The initial search yielded 95 studies, of which 30 studies were included in the current systematic review. The underlying disorders were obesity, type 2 diabetes, breast and colorectal cancers, depression, and metabolic syndrome. These studies found an association between FTO gene polymorphisms and obesity in the Iranian population, but the relationship with other NCDs was debatable. Even though, other diseases such as diabetes and metabolic syndrome, which are closely related to obesity, may also be associated with FTO gene polymorphisms.

Conclusion

FTO gene polymorphism appears to play a role in the occurrence of NCDs. Some of the study results may be misleading due to ethnic differences and the effect of other genetic factors on disease onset, which needs to be investigated further. Finally, FTO gene polymorphisms can be studied as a preventive or therapeutic target.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-022-01139-4.

Preventive effect of probiotics supplementation on occurrence of gestational diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Gestational diabetes mellitus (GDM) is a health challenge during pregnancy and is associated with adverse effects. Dysbiosis of the gut microbiota may play a role in developing inflammation and insulin resistance observed in GDM. Probiotics are supposed to be influential in preventing GDM since they can alter the composition of microbiota in the intestine. Despite the existing studies on the therapeutic effects of probiotics in women with GDM, in this study we aim to systematically review and meta-analyze the results of randomized control trials (RCTs) on the beneficial effects of probiotics supplements on the prevention of GDM in healthy pregnant women.

METHODS

Web of science, Scopus and PubMed databases were searched via a precise strategy to gather RCTs related to our study. Duplication removal, screening and data extraction were conducted by two researchers, independently. Quality assessment of eligible studies was conducted by Cochrane risk of bias tool. Meta-analysis was conducted using the random effects model due to substantial heterogeneity among studies.

RESULTS

Ten articles met our eligibility criteria from our initial search of 451 articles. Two thousand nine hundred and twenty-one participants without previously diagnosed glucose disturbance were included in our analysis. Probiotics reduced GDM incidence by 33% (RR = 0.67, 95% CI: 0.47, 0.95), while greater effect was detected in trials using multiple-strains probiotics (RR = 0.65, 95% CI: 0.42, 0.99). We did not detect any significant benefits or harms related to probiotics supplements on secondary outcomes including GDM related infantile and maternal complications including preeclampsia, caesarian section, mothers' weight gain during pregnancy, prematurity, macrosomia, hypoglycemia, NICU admission, and birth weight.

CONCLUSION

Probiotics supplementation may reduce the incidence of GDM and help control glucose parameters in pregnant women. Further studies are warranted regarding the GDM-related maternal and infantile complications.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022315550, identifier: CRD42022315550.

Effect of vitamins C and E on cancer survival; a systematic review

PURPOSE

Association between vitamins C (VC)/ E (VE) and cancer survival is inconsistent. This systematic review is aimed to summarize trials for effects of VC/VE on cancer survival.

METHODS

Relevant English trials were retrieved from PubMed, Cochrane Library, Embase, Web of Science, Scopus databases, and Clinicaltrials.gov through 21/June/2022. Inclusion criteria were all trials which assessed sole/combinations intake of VC/VE on survival rate, mortality, or remission of any cancer. Exclusion criteria were observational and animal studies.

RESULTS

We reached 30 trials conducted on 38,936 patients with various cancers. Due to severe methodological heterogeneity, meta-analysis was impossible. High dose VC + chemotherapy or radiation was safe with an overall survival (OS) 182 days - 21.5 months. Sole oral or intravenous high dose VC was safe with non-significant change in OS (2.9-8.2 months). VE plus chemotherapy was safe, resulted in stabling diseases for 5 years in 70- 86.7% of patients and OS 109 months. It was found 60% and 16% non-significant reductions in adjusted hazard ratio (HR) deaths or recurrence by 200 mg/d tocotrienol + tamoxifen in breast cancer, respectively. Sole intake of 200-3200 mg/d tocotrienol before resectable pancreatic cancer was safe and significantly increased cancer cells' apoptosis. Combination VC and VE was non-significantly reduced 7% in rate of neoplastic gastric polyp.

CONCLUSION

Although our study is supported improvement of survival and progression rates of cancers by VC/VE, more high quality trials with large sample sizes are required to confirm.

PROSPERO REGISTRATION NUMBER

CRD42020152795.

Trimethylamine N-Oxide as a potential risk factor for non-communicable diseases: A systematic review

Background:

Trimethylamine N-Oxide (TMAO), as a gut microbiota-derived metabolite, has been associated with a number of chronic diseases like cardiovascular diseases.

Objective:

Considering the increasing prevalence of non-communicable diseases (NCDs), we conducted a comprehensive overview to discuss the TMAO association with NCDs.

Methods:

A comprehensive search has been conducted on PubMed, Web of Science, and Scopus databases up to December, 2020. The inclusion criteria were all related observational studies that surveyed the association between TMAO levels and non-communicable diseases. Interventional studies, animal experiments, reviews, case reports, letters, congress abstracts, and studies that were not published in English were excluded. Moreover, related review studies were separately discussed.

Results:

Within 2191 recorded studies, 99 cross-sectional, case-control and cohort studies met the inclusion criteria. The most common diseases associated with TMAO levels are cardiovascular diseases, diabetes, kidney disease, stroke, inflammatory diseases, neurological disorders, and cancer. Elevated TMAO levels as a consequence of alteration in gut microbiota composition and dietary intake can lead to the incidence of NCDs. The high levels of TMAO can disrupt the homeostasis of glucose and lipids and induce inflammation that leads to serious NCDs.

Conclusion:

There is a dose-response relationship between TMAO levels and NCDs progression. Therefore, it can be studied as a therapeutic target or prognostic biomarker for dealing with NCDs.

The Role of Gut Microbiota-Brain Axis in Pathophysiology of ADHD: A Systematic Review

OBJECTIVE

The main goal of this systematic review is to summarize evidences regarding alterations of microbial composition in ADHD cases and uncover underlying mechanisms.

METHODS

A comprehensive search was conducted on PubMed, Web of Science, and Scopus databases up to March 2021. All the observational studies including case-control, cross-sectional, and cohorts investigating the correlations between the gut microbiota and ADHD in both adults and children were included.

RESULTS

We found eight eligible studies. Enterococcus, Bifidobacterium, and Odoribacter were increased which may lead to impaired dopamine related functions in CNS. Moreover, decrease of Faecalibacterium frequency in ADHD could result in higher permeability and crossing of inflammatory cytokines. Regarding the short chain fatty acids-producing bacteria, Ruminococcaceae family decreased and Bacteroides uniformis and Bacteroides ovatus species increased.

CONCLUSION

Gut microbiota correlation with ADHD and its underlying mechanisms could open new windows for developing novel therapies of ADHD by manipulating microbiota.

Effect of garlic extract on weight loss and gut microbiota composition in obese women: A double-blind randomized controlled trial

Objective

From a nutritional perspective, garlic extract could be a prebiotic product, which is useful for obese subjects, and one of its health-promoting underlying mechanisms is modulating gut microbiota composition. In this randomized double-blind clinical trial, the goal was to determine the effect of Allium (garlic extract) on anthropometric indices and gut microbiota composition in obese women following a low-calorie diet.

Materials and methods

Forty-three obese women were randomly divided into garlic extract (400 mg Allium sativum powder containing 1,100 mcg allicin/tablet) or placebo groups. During the 2 months of the study, each participant took two tablets per day. At the beginning and at the end of the clinical trial, anthropometric measurements were done and blood and fecal samples were collected. We evaluated the gut microbiota composition using quantitative real-time PCR.

Results

In total, 16 subjects in each group completed the 2-month trial. Allium and placebo groups’ participants had mean ages of 37.8 ± 7.4 and 34.2 ± 6.8 years, respectively (P > 0.05). Baseline body mass index (BMI) was significantly different between groups, subjects in the placebo group had lower BMI compared with the Allium group (P < 0.05). Allium and placebo caused a 1.7% and 2.7% decrease in BMI from the baseline values, respectively (P < 0.01). Fasting insulin level significantly decreased in the both groups (P < 0.01). Level of homeostasis model assessment of insulin resistance (HOMA-IR) has decreased significantly in the Allium group (P = 0.007). The frequency of Akkermansia had decreasing trend while the abundance of Faecalibacterium and Bifidobacterium showed increasing trend in the Allium group.

Conclusion

In the both groups, a decrease in BMI and other anthropometric indices has been observed. Despite weight loss after following a low-calorie diet and taking Allium, slight changes have been shown in the composition of gut microbiota in obese women.

Trial registration

This trial was registered in the Iranian Registry of Clinical Trials (IRCT) (code: IRCT090420001825N2).

Eating habits of children and adolescents during the COVID-19 era: A systematic review

The COVID19 pandemic has affected all aspects of people's lives. Eating habit plays a crucial role in children and adolescents' physical and mental development and the impacts might last until adulthood. This systematic review aimed to summarize a comprehensive and updated overview of eating habits changes due to COVID19 confinements among children and adolescents. A systematic literature search was performed in three databases for all the English studies published from the start of the confinements until April 2022. Two researchers screened articles independently and included observational studies which evaluated children's and adolescents' eating habits before and during confinements. The quality of the included studies was assessed by Newcastle-Ottawa Quality Assessment checklists for cross-sectional and cohort studies. Among 2,436 studies, 39 final full-text articles were included. The total participants of this systematic review consist of 157,900 children and adolescents. Seven categories were identified: daily eating patterns, junk food, beverage, fruits and vegetables, milk and dairy, protein-rich foods, and legumes and cereals. In summary, most of the included studies reported a significant increase in consumption of home-cooked meals, amount of food, snack, french fries, sweets, fruits, vegetables, legumes, bread, and bakery products. On the other hand, studies demonstrated significantly lower intake of fast food and soft drink. The studies reported controversial results about breakfast consumption, sugar-added drinks, caffeinated drinks, milk and dairy products, protein-rich foods (including meat, fish, egg and chicken, and poultry), rice, and cereal. Changes in children's and adolescents' eating habits during the COVID-19 era were both positive and negative, for example, a decrease in fast food, fruit, and vegetable consumption vs. an increase in snacking and sweet consumption. Both changes have significant short-term and long-term impacts on population health. This study could provide us with insight into the changes in eating habits in children and adolescents in the COVID-19 era which we can use to limit the negative consequences on health.

How did lockdown and social distancing policies change the eating habits of diabetic patients during the COVID-19 pandemic? A systematic review

Background

After the declaration of the COVID-19 pandemic, governments established national lockdowns and social distancing as an effective plan to control this disease. As a result of the lockdown policies, diabetic patients` access to food products, medication, and routine follow-ups is disrupted, making it difficult for them to control their disease.

Methods

International databases, including PubMed/Medline, Web of Science, and Scopus, were searched until April 2022. All observational studies included assessing the impact of lockdown and social distancing on eating habits (as primary outcome), and glycemic and anthropometric indices (as secondary outcomes) of diabetic patients during the COVID-19 pandemic. The Newcastle-Ottawa Quality Scale was used to assess the quality rating of the studies.

Results

Overall, 22 studies were included in this systematic review, the results of which varied in different communities. In most studies, consumption of grains, fruits, and vegetables was reported to increase. On the other hand, consumption of snacks and sweets was reported to increase in other surveys. During the COVID-19 lockdown, most diabetic patients preferred to cook meals at home, using less takeout, fast foods, and alcoholic drinks. Although the patients mostly improved their eating habits, the glycemic and anthropometric indices were contradictory in different studies. Studies showed that the eating habits of diabetic patients vary from country to country, even in some cases and studies done in the same country showed different results. For example, all the studies done in Japan showed an increase in the consumption of snacks and sweets, leading to weight gain in the patients. However, conflicting results in eating habits have been observed in studies conducted in India.

Conclusion

The lockdown policies have led to a beneficial change in the eating habits of diabetic patients to consume more fruits and vegetables and reduce the consumption of animal protein products and alcoholic beverages. While some diabetic patients have increased consumption of snacks and sweets, leading to a disturbance in their glycemic and anthropometric indices control. Understanding the consequences of lockdown and social distancing of the diabetic patient during the COVID-19 pandemic can help public health authorities make better recommendations to improve glycemic control.

Effect of vitamin D supplementation on cardiac-metabolic risk factors in elderly: a systematic review and meta-analysis of clinical trials

BACKGROUND

There has been a longstanding interest in the potential effect of vitamin D in preventing cardiac-metabolic diseases. However, there are divergent results regarding the impact of vitamin D supplementation (VDS) on managing cardiac-metabolic outcomes in the elderly population.

MATERIAL AND METHOD

We systematically searched electronic databases; Web of Science, PubMed, Scopus, EMBASE, Cochrane, and ProQuest. We included all trials that evaluated the effect of VDS on cardiac-metabolic risk factors in the elderly population, which were published until 30 September 2021. The effects of VDS on cardiac-metabolic outcomes were assessed using standardized mean difference (SMD). A random-effect model was used to pool the SMD and 95% confidence interval (CI).

RESULT

The literature search identified 4409 studies, of which 12 trials met inclusion criteria. Results of random effect meta-analysis indicated a significant reduction in total cholesterol (TC) (SMD: - 0.14 mg/dl; 95% CI: - 0.25, - 0.02) and triglyceride (TG) (SMD: - 0.45 mg/dl; 95% CI: - 0.86, - 0.04) with VDS compared to the placebo. The subgroup analyses revealed that the reduction of TG in patients with diabetes and vitamin D deficiency was significant. Furthermore, short-term intervention (≤ 6 months) induced a significantly lower level of TG and insulin in comparison to longer duration (> 6 months).

CONCLUSION

The study suggests that VDS could improve insulin concentration and dyslipidemia in the elderly population. The systematic review was registered in Alborz university of medical sciences with 2060-01-03-1397 number and the Ethics council IR.ABZUMS.REC.1397.207 number.

Effects of probiotic supplementation on major cardiovascular-related parameters in patients with type-2 diabetes mellitus: a secondary-data analysis of a randomized double-blind controlled trial

BACKGROUND

Patients with type-2 diabetes mellitus (T2DM), have a higher risk of future cardiovascular diseases (CVD). Meanwhile, probiotics are shown to positively impact CVD-related parameters. This randomized controlled trial sought to evaluate the effects of probiotic supplementation on fundamental CVD-related parameters including atherogenic index of plasma (AIPs), blood pressure, the Framingham risk score, and antioxidant markers in patients with T2DM.

METHODS

Eligible participants were randomly assigned to receive 2 capsules/day of probiotics [each containing 500 mg of L.acidophilus(5 × 10¹⁰ CFU/g), L.plantarum(1.5 × 10¹⁰ CFU/g), L.fermentum(7 × 10⁹ CFU/g), L.Gasseri(2 × 10¹⁰ CFU/g) and 38.5 mg of fructo-oligo-saccharides], or placebo for 6 weeks. Systolic and diastolic blood pressures (SBP and DBP, respectively), mean arterial blood pressure (MAP), atherogenic indices (the ratios of TC/HDL-C, LDL-C/HDL-C, and logTG/HDL-C), the 10-year Framingham CVD risk score, as well as total anti-oxidant capacity (TAC), paraoxonase (PON) and total oxidant status (TOS) were evaluated before and after the study. Final analyses were adjusted based on baseline parameters, and potential covariates including age, sex, PUFA and sodium intakes.

RESULTS

Sixty participants completed the study. Compared with placebo, probiotic supplementation resulted in a significant decrease in SBP[-9.24 mmHg(- 14.5, - 3.9)], DBP[- 3.71 mmHg(- 6.59, - 0.83)], MAP[- 5.55 mmHg(- 8.8, - 2.31)], the Framingham risk categories [medium-low(1.5) vs. 2 (medium)] and logTG/HDL-C ratio [- 0.08 (- 0.14, 0)] (All P < 0.05) at the end of the study. No significant changes were observed in the antioxidant markers.

CONCLUSION

Overall, probiotic supplementation for 6 weeks led to a significant improvement in major CVD-related parameters in populations with T2DM, suggesting the possible beneficial role of probiotics in lowering the risk of future CVDs associated with diabetes. Nevertheless, more studies are needed to confirm the veracity of these results.

TRIAL REGISTRATION

IRCT2013100714925N1 (registered on November, 9th, 2013).

Trend of passive smoking and associated factors in Iranian children and adolescents: the CASPIAN studies

Background

It is well documented that, similar to active smokers, passive smokers are also at an increased risk of developing non-communicable diseases, and it could impose high financial costs on the healthcare system. This study aimed to evaluate the trend of passive smoking and related determinants during the three phases of a school-based surveillance program.

Methods

This is a secondary study using the national data obtained from three phases of the surveillance program entitled The Childhood and Adolescence Surveillance and Prevention of Adult Noncommunicable Disease (CASPIAN) study, conducted from 2008 to 2014 on Iranian children and adolescents living in urban and rural areas of 30 provinces in Iran. Participants were selected by cluster multistage sampling method.

Results

Overall, the study participants consisted of 33,288 students (50.5% boys) with a mean (± SD) age of 12.8 ± 3.2 years. The passive smoking rate was significantly increased from 35.6% in 2008 to 43.2% in 2015 among children and adolescents. According to the multivariate logistic regression, father’s university education, mother’s employment, life satisfaction, and socioeconomic status had a protective role regarding second-hand smoke exposure. In contrast, the father’s self-employment had a positive role in increasing the rate of passive smoking.

Conclusion

Considering the increasing trend of passive smoking and its considerable adverse health effects, it is necessary to implement large-scale public interventions to reduce the rate and hazards of exposure to tobacco smoke.

Interactive relationship between Trp metabolites and gut microbiota: The impact on human pathology of disease

Tryptophan (Trp), an α-amino acid, is the precursor of serotonin (5-hydroxytryptamine, 5-HT), which is involved in a variety of features of metabolic function and human nutrition. Evidence highlights the role of Trp metabolites (exclusively 5-HT) in the gastrointestinal (GI) tract; however, the mechanisms of action involved in the release of 5-HT in the GI tract are still unknown. Considering the fact that variations of 5-HT may facilitate the growth of certain GI disorders, gaining a better understanding of the function and release of 5-HT in the GI tract would be beneficial. Additionally, investigating Trp metabolism may clarify the relationship between Trp and gut microbiota. It is believed that other metabolites of Trp (mostly that of the kynurenine pathway) may play a significant role in controlling gut microbiota function. In this review, we have attempted to summarize the current research investigating the relationship of gut microbiota, Trp, and 5-HT metabolism (with particular attention paid to their metabolite type, as well as a discussion of the research methods used in each study). Taking together, regarding the role that Trp/5-HT plays in a range of physical and mental diseases, the gut bacterial types, as well as the related disorders, have been exclusively considered.

Is There Any Link between Cognitive Impairment and Gut Microbiota? A Systematic Review

BACKGROUND

Symptoms of cognitive impairments vary from mild without clinical manifestation to severe with advanced signs of dementia or Alzheimer's disease (AD). Growing evidence in recent years has indicated the association between the brain and gut microbiota, which has been described as the "gut-brain axis." This systematic review seeks to summarize the primary results from recent human and animal studies regarding the alteration of gut microbiota composition in cognitive disorders.

METHODS

A systematic literature search was conducted on PubMed, Scopus, and Web of Science databases up to August 2020. The full texts of the papers were analyzed to retrieve the relevant information.

RESULTS

Totally, 24 observational studies (14 animal and 13 human studies) were included. Most of the animal studies were performed on mouse models of AD. Human studies were conducted on patients with Parkinson's disease (3 studies), AD (4 studies), poststroke cognitive impairment patients (1 study), and patients with mild to severe cognitive impairment without mention to the cause of disease (5 studies). More recent evidence suggests that throughout aging Firmicutes and Bifidobacteria decrease but Proteobacteria increases.

CONCLUSIONS

The gut microbiota may alter brain function or trigger various psychiatric conditions through the gut-brain axis. Prospective studies are needed in order to explore the role of the gut microbiota in the etiology of dementia and to achieve clinical recommendations.

Dietary diversity score and cardio-metabolic risk factors: an updated systematic review and meta-analysis

CONTEXT

Dietary diversity score (DDS) has been known as a useful and convenient indicator of overall diet quality. Previous studies have reported the association between DDS and health problems such as diabetes, metabolic syndrome and cardiovascular disease.

OBJECTIVES

This systematic review and meta-analysis aimed to assess the association between dietary diversity score (DDS) and cardio-metabolic risk factors such as obesity and overweight, lipid profile, blood pressure, metabolic syndrome (MetS) and diabetes.

DATA SOURCES

We systematically searched PubMed and NLM Gateway, Scopus and Institute of Scientific Information (ISI) by up to October 2019.

DATA EXTRACTION

All observational studies which assessed the association of DDS with cardio-metabolic risk factors including anthropometric measures, blood pressure, lipid profile, glycemic indices and MetS without limitation in time of publication and language were included and critically reviewed by two independent experts. Random-effects meta-analysis was used to estimate the effect sizes.

DATA ANALYSIS

Among 843 documents retrieved from literature search, 23 studies met the inclusion criteria for systematic review, and 18 studies were eligible for meta-analysis. Random-effects meta-analysis showed that the association of DDS with obesity, abdominal obesity, overweight, body mass index, MetS, diabetes, blood pressure, and lipid profile (TC, LDL, HDL) was not statistically significant. On the other hand, the association of DDS and TG was statistically significant (SMD: - 0.23, 95% CI - 0.45, - 0.01).

CONCLUSIONS

Our findings revealed that there was no significant association between DDS and cardio-metabolic risk factors. Reassessment of the overall DDS tool as a criterion of diet quality and production of new and valid DDS standard tools is highly desirable. More high-quality studies are also needed to confirm the findings of this study.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42020157127.

LEVEL OF EVIDENCE

Level I, systematic reviews and meta-analyses.

Determinants of life satisfaction and self-rated health in Iranian children and adolescents: a structure equation model

Background

Life satisfaction (LS) and self-rated health (SRH) are related with health outcomes. It is expected that these items are also related to healthy behaviors. Therefore, this study was conducted in order to find out the main determinants of LS and SRH in nationwide representative sample of Iranian children and adolescents.

Methods

This study was performed on 13,834 students aged 7–18 years who were selected by multistage, stratified cluster sampling method from 30 provinces of Iran. Life satisfaction and SRH were assessed through a questionnaire based on World Health Organization-Global School-based Student Health Survey protocols. Path analysis was applied to evaluate the relationships among the study variables using the structural modeling.

Results

Life satisfaction was directly affected by age (− 0.037 in boys & -0.028 in girls); sedentary time (0.055 in boys & 0.048 in girls); school satisfaction (0.249 in boys & 0.250 in girls); and well-being (0.186 in boys & 0.176 in girls). Self-rated health was directly affected by LS (0.28 in boys & girls) and school satisfaction (0.21 in boys & 0.22 in girls); and indirectly affected by age (− 0.046 in boys & -0.017 in girls); sedentary time (− 1.99 in boys & -0.145 in girls); family size (− 0.005 in boys & -0.014 in girls); and socio-economic status (0.015 in boys & 0.058 in girls).

Conclusions

This study indicated that school satisfaction had the greatest positive direct effect on both LS and SRH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-03044-w.

Microbiome alterations in women with gestational diabetes mellitus and their offspring: A systematic review

AIMS

Gestational diabetes mellitus (GDM) is a metabolic disorder that might predispose pregnant women to develop type 2 Diabetes Mellitus or lead to severe adverse outcomes in their offspring. One of the factors that have been thought to be involved in the pathology behind this disorder is the microbiome. In this systematic review, we comprehensively review the documents regarding the microbiota alterations in different tracts of pregnant women with GDM and their offspring.

METHODS

A comprehensive search was conducted in major databases including MEDLINE (PubMed), Scopus, and Web of sciences up to August 2021. Data on the demographics, methodology, and microbiome alterations were extracted and classified according to the type of microbiome in pregnant women with GDM and their offspring. The quality of studies was assessed using the Newcastle-Ottawa Scale (NOS).

RESULTS

In 49 articles which were retrieved, the findings were variable on the level of changes in alpha and beta diversity, enrichment or depletion in phyla, genera, species and OTUs, in each microbiome type. Although there were some inconsistencies among the results, a pattern of significant alterations was seen in the gut, oral, vaginal microbiome of women with GDM and gut, oral, and placental microbiome of their offspring.

CONCLUSION

Even though the alteration of the microbiome of the different tracts was seen in the cases of GDM, the inconsistency among the studies prevents us from identifying unique pattern. However, the results seem promising and further studies that overcome the confounding factors related to the demographics and methodology are needed.

Association of short stature and obesity with cardio-metabolic risk factors in Iranian children and adolescents: the CASPIAN-V study

Purpose

The object of the present study was to examine the relationship of short stature and obesity with cardio-metabolic risk factors in children and adolescents from Iran.

Methods

Present nationwide cross-sectional study was conducted as a part of the fifth survey of CASPIAN study on 7 to 18 years old children and adolescents from 30 provinces of Iran in 2015. Short stature and excess weight were defined as age and sex-specific height lower than 5^th percentile and BMI higher than 85^th percentile respectively. The multivariate logistic regression model was applied to assess the aim of the study.

Results

A total of 3844 children and adolescents (52.4%: boys, 72.2%: urban areas) with an average age of 12.45 ± 3.04 years were enrolled in this study. The prevalence of short stature, excess weight and combined-short stature and excess weight was estimated as 15.8%, 17.6% and 2.2%. Odds of abdominal obesity in children with only short stature (OR: 2.11, 95%CI: 1.59-2.80), only excess weight (OR: 17.38, 95%CI: 13.89-21.75) and combined-short stature and excess weight (OR: 22.83, 95%CI: 13.93-37.39) were higher than children with normal-height and weight. Moreover, odds of high BP and metabolic syndrome were further in the students with combined excess weight and short stature compared to the normal-height and weight group.

Conclusion

We found that abdominal obesity, hypertension, and metabolic syndrome in short stature and obese children and adolescents were greater than those with normal-height and weight. Further prospective evaluations are required to clarify the association between short stature and cardio-metabolic risk factors.

Gut microbiota modulation as a possible mediating mechanism for fasting-induced alleviation of metabolic complications: a systematic review

BACKGROUND

Intermittent fasting has been reported to have positive effects on obesity, diabetes, cardiovascular diseases, hypertension, and several neurodegenerative diseases through different mechanisms such as alteration in the gut microbiota. This systematic review was conducted with the aim of providing an overview of the existing animal and human literature regarding the gut microbiota alterations in various fasting regimens.

METHOD

A systematic literature search was conducted on PubMed, Scopus and Web of Science databases up to May 2021 to find all relevant studies examining the gut microbiota alteration during the fasting. Original researches on animal models or human patients were included in this study.

RESULTS

The search fulfilled 3072 documents from which 31 studies (20 animal and 11 human studies) were included. Upon fasting, abundance of several beneficial bacteria including Lactobacillus and Bifidobacterium shifted significantly. Moreover, some taxa, including Odoribacter which negatively associated with blood pressure bloomed during fasting. Ramadan fasting, as a kind of intermittent fasting, improves health parameters through positive changes in gut microbiota including upregulation of A. muciniphila, B. fragilis, Bacteroides and butyric acid-producing Lachnospiraceae.

CONCLUSION

The findings suggest that different fasting regimens including alternate-day fasting, calorie- and time-restricted fasting programs and Ramadan fasting could promote health maybe through the modulation of gut microbiome. However, further studies are needed to explore properly the connection between gut microbiota and meal frequency and timing.

Association of vitamin D status and cardio-metabolic risk factors in children and adolescents: the CASPIAN-V study

BACKGROUND

Metabolic syndrome (MetS) starts from early life and is one of the important underlying factors for non-communicable diseases (NCDs) in adulthood. Controversial evidence exists on the role of vitamin D deficiency in increasing the risk of pediatric MetS.

OBJECTIVE

This study aimed to assess the relationship between vitamin D level with MetS and its components in children and adolescents.

METHODS

This nationwide cross-sectional study was performed as part of a surveillance program in Iran. Participants were 2596 students, aged 7 to 18 years, living in 30 provinces. In addition to filling questionnaires, a physical examination was conducted, and blood samples were collected. The serum concentration of 25-hydroxy vitamin D (25(OH)D) was measured using the direct competitive immunoassay chemiluminescence method.

RESULTS

2596 students with a mean age of 12.2 y (55.1% boys) were recruited. Prevalence of vitamin D deficiency and insufficiency in participants was 10.6% (n = 276), and 60.5% (n = 1570), respectively. The prevalence of MetS was higher in the vitamin D deficient group. Students with deficient vitamin D levels had higher odds of MetS (OR: 4.25, 95%CI: 2.26-7.98), abdominal obesity (OR: 2.24, 95%CI: 1.61-3.12), low HDL-C (OR: 1.65, 95%CI: 1.18-2.30) and high fasting blood sugar (OR: 2.56, 95%CI: 1.43-4.57) in comparison to those with sufficient level of vitamin D.

CONCLUSION

Vitamin D deficiency was associated with increased odds of MetS and its components in the Iranian pediatric population. These findings underscore the importance of prevention and control of vitamin D deficiency in preventative programs against NCDs.

Long-term Trends in Hypertension Prevalence, Awareness, Treatment, and Control Rate in the Middle East and North Africa: a Systematic Review and Meta-analysis of 178 Population-Based Studies

PURPOSE OF REVIEW

This study investigated and pooled the long-term trends in prevalence, awareness, treatment, and control of hypertension (HTN) in the Middle East and North Africa (MENA) region. In this systematic review and meta-analysis, we searched MEDLINE/PubMed, Web of Science, Google Scholar, EMBASE, and Scopus between database inception and November 2020. All cross-sectional studies that investigated the prevalence of pre-HTN, HTN, awareness, treatment, and control in the MENA counties were included. The selection study, data extraction, and quality assessment were conducted by two investigators independently. Heterogeneity between studies was assessed using Cochran's Q test and I-squared, and due to sever heterogeneity between studies, the random effect model was used to pool the estimates. Sensitivity analysis was performed to estimate the long-term trends in prevalence, awareness, treatment, and control rates of HTN according to definition of HTN as systolic blood pressure of 140 mm Hg or more, or diastolic blood pressure of 90 mm Hg or more, or being on pharmacological treatment for HTN.

RECENT FINDINGS

Overall, 178 studies met the inclusion criteria. Studies comprised 2,262,797 participants with a mean age of 45.72 ± 8.84 years. According to random effect model, the pooled prevalence of pre-HTN and HTN was 33% (95% CI 28, 39) and 26% (25, 27), respectively. Over the past three decades, prevalence of hypertension increased significantly in the region. The pooled awareness, treatment, and control rates were 50% (48, 53), 41% (38, 44), and 19% (17, 21), receptively. The pooled awareness, treatment, and control rates of HTN were lower significantly in men than women. According to definition of HTN as blood pressures above 140/90 mm Hg, over the past three decades, although the awareness and treatment rates did not change significantly, the control rates improved significantly in the region. The findings showed that HTN is a significant public health problem in the MENA region. Although there are low levels of pooled awareness, treatment, and control rates, the control rates improved over the past three decades in the region.

The effects of dietary selenium supplementation on inflammatory markers among patients with metabolic diseases: a systematic review and meta-analysis of randomized controlled trials

Purpose

Selenium (Se) is a trace element having significant effects on human metabolism. Recent studies suggest that Se supplementation have a pivotal effect on the inflammatory markers. Therefore, the aim of this study was to assess the effect of Se supplementation on plasma inflammatory markers including C-reactive protein (CRP) and high-sensitivity C-reactive protein (hs-CRP) and nitric oxide (NO) as a stress oxidative index, among patients with metabolic diseases.

Methods

To assess the effects of Se on the inflammatory markers, following the PRISMA-P guidelines, we systematically searched ISI/WOS, PubMed/MEDLINE, and Scopus for studies that assessed the effect of Se supplementation on the inflammatory markers. Data extraction was performed by two independent investigators. Using the random effects or fixed-effects model depending on the results of heterogeneity tests was used to estimate the pooled standardized mean difference (SMD). Heterogeneity between studies was assessed using Cochran's Q test and I² index.

Results

The initial search revealed 3,320 papers. After screening process and considering inclusion criteria, 7 publications were eligible for inclusion in the meta-analysis. The meta-analysis results showed that Se supplementation did not significantly affect CRP and hs-CRP concentrations (mean difference (MD) = -0.15; 95% CI: -0.55- 0.23; P = 0.43). Subgroup analysis of CRP type showed that Se supplementation significantly decreased hs-CRP level (pooled SMD = -0.44; 95% CI: -0.67-0.21). Moreover, no significant change was observed in NO level by continuing to take Se supplementation, (pooled SMD: 0.003, 95%CI: -0.26, 0.26).

Conclusions

This study revealed that Se supplementation would have desirable effects on cardio-metabolic indicators through affecting the levels of inflammatory markers. Given the importance of concerns, more attention should be given to more prospective studies with longer follow-up.

Assessment of fecal Akkermansia muciniphila in patients with osteoporosis and osteopenia: a pilot study

OBJECTIVES

Osteoporosis is characterized by slow deterioration in bone mass and disruption of its structure, leading to an increased risk of bone fractures. Gut microbiota plays an important role in the transport and absorption of nutrients needed for bone health. Akkermansia muciniphila is one of the gut microbiota members that its beneficial role in prevention of metabolic disorder was suggested. The aim of the current pilot study was the assessment of fecal A. muciniphila in patients with osteoporosis and osteopenia.

METHODS

A total of 36 subjects including eight with osteoporosis (three men and five women), eight with osteopenia (two men and six women), and 20 normal controls (six men and 14 women) were selected. Microbial genome was extracted from fresh stool samples. The bacterial load was determined by quantitative real-time PCR using 16S rRNA specific primers.

RESULTS

The participants' mean age in the osteoporosis, osteopenia and control groups were 61.71, 45 and 45.05 years, respectively. The majority of osteoporosis patients were post-menopause women, while in osteopenia group was pre-menopause. There were significant differences in terms of age, T-score, Z-score, and menopause among groups (P value < 0.05). The presence of A. muciniphila was higher in the healthy group compared to osteopenia group; however, these differences were not statistically significant.

CONCLUSIONS

In conclusion, however, there was no statistically significant difference between the study groups; it seems that the load of A. muciniphila may be related to bone health. Further in vivo and in vitro studies are needed to investigate the immunological and biochemical pathways.

Withdrawal reasons of randomized controlled trials on type 2 diabetes: a systematic review

PURPOSE

Type 2 diabetes mellitus (T2DM) is the subject of numerous randomized controlled trials (RCTs). The validity of RCTs may be threatened by attrition bias due to the discontinuation of the study. The aim of this systematic review is to evaluate the reasons of patient's withdrawal from these RCTs.

METHODS

A systematic literature search on PubMed, Cochrane Library, Web of Science, and Scopus databases was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram. The aim was to obtain all relevant blinded RCTs published before January 2017 in which the effectiveness of synthetic drugs, vitamins/minerals were compared to that of placebo or active control in T2DM. The quality of RCTs was assessed using the Jadad score. The frequency of withdrawal reasons was presented based on treatments with placebo/active control, national/international level of the studies, and publication year. Meta-analysis was not performed due to the heterogeneity.

RESULTS

Overall, 1368 articles comprising of 640,780 subjects were included. In the majority of the RCTs (75.0%), the intervention and the placebo arms were compared. Most of the included studies (96%) were classified in the high-quality category (Jadad score≥3). The highest proportion of reported withdrawal cases was found in international studies, national RCTs conducted in Japan, and RCTs published in 2011. The withdrawal reasons were reported for 91,669 (63.75%) of the total 143,794 participants who had withdrawn from these studies. The main reported reasons were "adverse effects" (24.04%), "withdraw consent" (16.10%), and "missing data" (11.08%). Variations in the reported withdrawal reasons were based on the country or published year. RCTs with triple blinded design as well as those in which anti-hyperlipidemia and anti-obesity medications were applied, showed significantly higher probability of reported the withdrawal.

CONCLUSION

High proportion of reported discontinuation in blinded RCTs on patients with T2DM was related to drug adverse effects. Overall, the total number and reason of drop out were unsatisfactory.

Validity of continuous metabolic syndrome score for predicting metabolic syndrome; a systematic review and meta-analysis

BACKGROUND

Nowadays, use of continuous metabolic syndrome (cMetS) score has been suggested to improve recognition of metabolic syndrome (MetS). The aim of this study was to evaluate the validity of cMetS scores for predicting MetS.

METHODS

We searched the electronic databases included MEDLINE/PubMed, Embase, ISI Web of Science, and Scopus from 1 January 1980 to 30 September 2020. Observational studies on participants with different cMetS scores were included in this meta-analysis. The sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR) and diagnostic odds ratio (DOR) with 95% CI were calculated.

RESULTS

Ten studies involving a total of 25,073 participants were included. All studies had cross-sectional design. The pooled sensitivity and specificity of cMetS scores for predicting MetS were 0.90 (95% CI: 0.83 to 0.95) and 0.86 (95% CI: 0.83 to 0.89), respectively. Moreover, cMetS scores had the pooled LR+ of 6.5 (95% CI: 5.0 to 8.6), and a pooled (LR-) of 0.11 (95% CI: 0.063 to 0.21). The pooled DOR of cMetS scores to predict MetS were 57 (95% CI: 26 to 127).

CONCLUSIONS

The high sensitivity and specificity of cMetS scores indicates that it has a high accuracy to predict the risk of MetS. Furthermore, the cMetS scores has a good ability to rule out healthy people.

STUDY REGISTRATION

This study was registered as PROSPERO CRD42020157273.

Percentile values for serum levels of vitamins A and D in Iranian children and adolescents: The CASPIAN-V study

OBJECTIVES

The reference values to determine vitamin A and D deficiency may vary based on ethnicity, age, and region of residence. The aim of this study was to determine the reference interval of circulating vitamin A and D levels among Iranian children and adolescents based on sex, age, and region of residence.

METHODS

This nationwide cross-sectional study was performed with 2596 students 7 to 18 y of age from the CASPIAN-V (Childhood and Adolescence Surveillance and Prevention of Adult Non- communicable disease) study. A parametric method was used to define the age-specific reference values by obtaining smooth centile curves and explicit formulae for the centile estimates and SD scores for both sexes and regions of residence.

RESULTS

Significant differences were found between the residents of rural and urban regions in terms of serum 25-hydroxyvitamin D [25(OH)D] and retinol concentration (P < 0.05). Boys (27 ± 8 versus 26.04 ± 10, P = 0.009). Children ages 7 to 12 y had higher serum 25(OH)D concentration than 13- to 18-y-old adolescents (26.96 ± 8 versus 26.04 ± 10, P = 0.007). The estimated reference interval for circulating 25(OH)D levels corresponding to the range between the 5th and 95th percentiles were 11.45 to 48.40 ng/mL in boys and 9.51 to 47.69 ng/mL in girls. Estimated reference intervals for serum retinol concentration among boys and girls corresponding to the 5th and 95th percentiles were 0.58 to 3.38 and 0.58 to 4.52, respectively. There were significant variations in both retinol and 25(OH)D concentrations across different age groups.

CONCLUSION

This study established the reference intervals for circulating 25(OH)D and retinol levels in Iranian adolescents and children in different age groups based on sex and region.

Comparison of psychological symptoms between infected and non-infected COVID-19 health care workers

BACKGROUND

Studies have shown that health care workers (HCWs), as front liners of the coronavirus (COVID-19) pandemic, are at high risk for psychological symptoms, but few studies have compared these symptoms in infected and non-infected HCWs. This study compares psychological symptoms among these two groups.

METHODS

In this cross-sectional study, 938 HCWs from various medical fields working in the leading general hospitals of Alborz province, Iran, were selected using a multistage sampling method. The participants had contact with COVID-19 patients. Post-traumatic stress disorder-8 (PTSD-8) is a validated questionnaire that we used to evaluate PTSD symptoms along with its subscales, including intrusion, avoidance, and hypervigilance. Also, the Depression, Anxiety, and Stress Scale-21 questionnaire was used to assess the severity of the aforementioned conditions in HCWs. Multivariate logistic regression was used to compare psychological symptoms in infected and non-infected HCWs.

RESULTS

Among 938 included HCWs, 55 had a history of confirmed COVID-19 infection. Prevalence of stress, anxiety, depression, intrusion, hypervigilance, and avoidance among infected HCWs were significantly higher in comparison to non-infected HCWs. In the multivariate logistic model, history of COVID-19 infection among HCWs was associated with a significantly increased risk of anxiety, depression, stress, intrusion, hyper-vigilance, and avoidance.

CONCLUSION

The present study showed that the HCWs with COVID-19 infection were at a high risk of displaying psychological symptoms. Therefore, it is also necessary to develop psychological support and interventions for HCWs, especially those who got infected with the virus.