Alcohol consumption and frailty risk: a dose-response meta-analysis of cohort studies.

BACKGROUND/AIMS: While previous studies suggest that light-to-moderate alcohol consumption may reduce the frailty risk, the dose-response relationship is still under question. To address the knowledge gap, we conducted a systematic review and dose-response meta-analysis of cohort studies to examine the association of alcohol consumption with the risk of both prefrailty and frailty in adults. METHODS: We searched MEDLINE (Ovid), PubMed and Scopus to identify relevant cohort studies published before 8 May 2024. The dose-response meta-analysis was performed to investigate the associations between alcohol drinking and the risk of developing pre-frailty and frailty. We used random-effects models to calculate pooled relative risks (RR) with 95% CIs. RESULTS: We included nine cohort studies with 64 769 participants and 15 075 cases, of which eight studies were rated to have a serious risk of bias as assessed by the ROBINS tool. Based on our analysis, each 12 g increase in alcohol intake did not appear to be associated with risks of prefrailty (RR: 1.08, 95% CI 0.89, 1.31; I2 = 91%, n = 3; GRADE = very low) and frailty (RR: 0.94, 95% CI 0.88, 1.00; I2 = 63%, n = 9; GRADE = low). The nonlinear dose-response meta-analysis indicates a slight inverse association with frailty risk up to an alcohol intake of 20 grams per day, beyond which an upward trend is observed. CONCLUSION: The inverse association found between moderate alcohol consumption and frailty risk appears to be stronger among older adults, which might be due to the lower and less popular alcohol consumption among older people than the general population. However, because this finding is based on low-quality evidence, more research is needed to develop specific dietary recommendations for alcohol consumption, particularly among young people.

Coffee consumption and caffeine intake in relation to risk of fractures: a systematic review and dose-response meta-analysis of observational studies.

BACKGROUND: Conflicting reports are available about the association of coffee or caffeine intake and risk of fracture. We performed the current updated systematic review and dose-response meta-analysis of coffee consumption and caffeine intake and risk of fracture to quantify this association. MATERIALS AND METHODS: PubMed/Medline, ISI Web of Science, and Scopus, Cochrane database were searched up to July 2021. Random-effects model or fixed-effects model was used to pool the study-specific effect sizes (ESs) and 95% confidence intervals (CIs). Dose-response relationship was examined using linear and non-linear dose-response analyses. The certainty of evidence was assessed using NutriGrade tool. RESULTS: Out of 22 eligible studies included in the meta-analysis, 15 had cohort and 7 had case-control design. We found no significant association between coffee consumption and risk of fracture, either based on pooling cohort (RR: 0.99; 95% CI: 0.88, 1.12; I2 = 71.4%, Pheterogeneity < 0.01) or case-control studies (OR: 1.13; 95% CI: 0.87, 1.46; I2 = 49.0%, Pheterogeneity=0.08). In the subgroup analysis of cohort studies, we observed that higher coffee intake was inversely associated with risk of fracture in men (RR: 0.85; 95% CI: 0.76 to 0.94). In addition, a positive association was seen between coffee consumption and risk of fracture in studies with less than 12 years of follow-up (RR: 1.14; 95% CI: 1.02 to 1.27). With regard to caffeine intake, a statistically significant positive association was seen with risk of fracture (RR: 1.15; 95% CI, 1.08 to 1.23; I2=26.6%, n = 8). In the dose-response analysis, we found that each additional 100 mg caffeine intake was marginally associated with 2% greater risk of fracture (RR: 1.02; 95% CI: 1 to 1.05; I2= 70.3%, n = 6). CONCLUSION: High coffee consumption was protectively associated with risk of fracture in men, while caffeine intake was positive associated with risk.

A systematic review and meta-analysis of prospective cohort studies on the association between alcohol intake and risk of fracture.

Previous studies on the association between alcohol intake and risk of fracture have reached conflicting findings. The aim of this systematic review and meta-analysis of prospective cohort studies was to summarize earlier studies on the association of alcohol intake with risk of fracture. A systematic search of PubMed, Scopus, and ISI Web of Science was conducted up to November 2020. Prospective cohort studies that had considered alcohol consumption as the exposure variable and fracture as the main outcome or as one of the outcome variables were included in this systematic review. Publications in which odds ratios (ORs), rate or risk ratios (RRs), or hazard ratios (HRs) and 95% confidence intervals (CIs) were reported, were included in the meta-analysis. In total, 40 prospective cohort studies including 5,084,303 participants and 170,916 subjects with fracture were included in this systematic review; of them 38 studies with a total sample size of 5,053,117 participants and 169,560 cases of fracture were included in the meta-analysis. Using a random-effects meta-analysis, we found a significant positive association between alcohol consumption and risk of total fractures (RR: 1.35; 95% CI: 1.01, 1.81) and any fractures (RR: 1.24; 95% CI: 1.11, 1.38). However, no significant association was observed between alcohol intake and risk of hip fractures (RR: 1.19; 95% CI: 0.96, 1.48), osteoporotic fractures (RR: 2.01; 95% CI: 0.76, 5.34), vertebral fractures (RR: 0.98; 95% CI: 0.68, 1.40), and wrist fractures (RR: 0.99; 95% CI: 0.85, 1.16). In conclusion, we found that alcohol consumption was positively associated with risk of total fractures and any fractures. However, we did not observe any significant association between alcohol consumption and risk of hip, osteoporotic, vertebral, and wrist fractures.

Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trials.

Clinical trial studies revealed conflicting results on the effect of Ashwagandha extract on anxiety and stress. Therefore, we aimed to evaluate the effect of Ashwagandha supplementation on anxiety as well as stress. A systematic search was performed in PubMed/Medline, Scopus, and Google Scholar from inception until December 2021. We included randomized clinical trials (RCTs) that investigate the effect of Ashwagandha extract on anxiety and stress. The overall effect size was pooled by random-effects model and the standardized mean difference (SMD) and 95% confidence interval (CIs) for outcomes were applied. Overall, 12 eligible papers with a total sample size of 1,002 participants and age range between 25 and 48 years were included in the current systematic review and meta-analysis. We found that Ashwagandha supplementation significantly reduced anxiety (SMD: -1.55, 95% CI: -2.37, -0.74; p = .005; I2  = 93.8%) and stress level (SMD: -1.75; 95% CI: -2.29, -1.22; p = .005; I2  = 83.1%) compared to the placebo. Additionally, the non-linear dose-response analysis indicated a favorable effect of Ashwagandha supplementation on anxiety until 12,000 mg/d and stress at dose of 300-600 mg/d. Finally, we identified that the certainty of the evidence was low for both outcomes. The current systematic review and dose-response meta-analysis of RCTs revealed a beneficial effect in both stress and anxiety following Ashwagandha supplementation. However, further high-quality studies are needed to firmly establish the clinical efficacy of the plant.

Dietary intake of branched-chain amino acids in relation to general and abdominal obesity.

PURPOSE: Despite the huge evidence on the link between dietary protein intake and obesity, limited studies have examined the role of individual amino acids in this regard. This study aimed to investigate the association between dietary total and individual BCAAs intake and odds of general and abdominal obesity in a large group of adults. METHODS: This cross-sectional study was conducted among 8691 adults aged 18-55 years in Isfahan, Iran. Dietary BCAAs were assessed using a validated dish-based 106-item semi-quantitative food frequency questionnaire (DS-FFQ). Information about weight and waist circumference was collected through a self-reported validated questionnaire. General obesity was defined as body mass index (BMI) ≥ 30 kg/m2, and abdominal obesity was defined as waist circumference (WC) ≥ 88 cm for women and ≥ 102 cm for men. RESULTS: Mean age of study participants was 36.8 ± 8.1 years. Prevalence of general obesity was 9.2% in men and 9.7% in women and that of abdominal obesity was 13.3% and 36.2% in men and women, respectively. We found that participants in the top tertile of total BCAAs intake had higher odds of general obesity compared with those in the bottom tertile (OR: 1.42; 95% CI: 1.09-1.84). Such significant association was seen in men (OR: 1.57; 95% CI: 1.05-2.34), but not in women (OR: 1.33; 95% CI: 0.94-1.89) in our stratified analysis. We found no significant association between total BCAAs intake and odds of abdominal obesity. Stratified by sex, no significant association was observed between total BCAAs intake and odds of abdominal obesity [for men: (OR: 1.10; 95% CI: 0.74-1.65) and for women: (OR: 1.08; 95% CI: 0.84-1.38)]. Assessing the association with individual BCAAs, a significant positive association was observed between dietary intake of valine (OR: 1.42; 95% CI: 1.10-1.84), leucine (OR: 1.43; 95% CI: 1.10-1.86), and isoleucine (OR: 1.42; 95% CI: 1.09-1.84) with general obesity. We observed no significant association between dietary intake of individual BCAAs intake and odds of abdominal obesity. CONCLUSION: Dietary BCAAs intake was associated with an increased odds of general obesity, in particular among men. No significant association was observed between dietary BCAAs and abdominal obesity. LEVEL OF EVIDENCE: Level V, descriptive cross-sectional study.

The effects of coenzyme Q10 supplementation on biomarkers of exercise-induced muscle damage, physical performance, and oxidative stress: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials.

PURPOSE: This study aims to elucidate the dose-dependent effect of coenzyme Q10 supplementation (CoQ10) on exercise-induced muscle damage (EIMD), physical performance, and oxidative stress in adults. METHODS: A systematic search was conducted through PubMed, Scopus, and ISI Web of Science databases up to August 2023, focusing on randomized control trials (RCTs) that investigated the effects of CoQ10 supplementation on EIMD recovery, physical performance and oxidative stress mitigation in adults. The weighted mean difference (WMD) and 95 % confidence interval (95 %CI) were estimated using the random-effects model. RESULTS: The meta-analysis incorporated 28 RCTs, encompassing 830 subjects. CoQ10 supplementation significantly decreased creatine kinase (CK) (WMD: -50.64 IU/L; 95 %CI: -74.75, -26.53, P < 0.001), lactate dehydrogenase (LDH) (WMD: -52.10 IU/L; 95 %CI: -74.01, -30.19, P < 0.001), myoglobin (Mb) (WMD: -21.77 ng/ml; 95 %CI: -32.59, -10.94, P < 0.001), and Malondialdehyde (MDA) (WMD: -0.73 µmol/l; 95 %CI: -1.26, -0.20, P = 0.007) levels. No significant alteration in total antioxidant capacity was observed post-CoQ10 treatment. Each 100 mg/day increase in CoQ10 supplementation was correlated with a significant reduction in CK (MD: -23.07 IU/L, 95 %CI: -34.27, -11.86), LDH (WMD: -27.21 IU/L, 95 %CI: -28.23, -14.32), Mb (MD: -7.09 ng/ml; 95 %CI: -11.35, -2.83) and MDA (WMD: -0.17 µmol/l, 95 %CI: -0.29, -0.05) serum levels. Using SMD analysis, "very large" effects on LDH and "moderate" effects on CK and MDA were noted, albeit nonsignificant for other outcomes. CONCLUSION: CoQ10 supplementation may be effective in reducing biomarkers of EIMD and oxidative stress in adults. Nevertheless, given the preponderance of studies conducted in Asia, the generalizability of these findings warrants caution. Further RCTs, particularly in non-Asian populations with large sample sizes and extended supplementation durations, are essential to substantiate these observations.

Effect of Low-Fat Diet on Depression Score in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials.

CONTEXT: Current evidence on the effect of a low-fat (LF) diet on depression scores has been inconsistent. OBJECTIVE: To explore the effect of an LF diet on depression scores of adults by systematic review and meta-analysis of randomized controlled trials (RCTs). DATA SOURCES: The PubMed, ISI Web of Science, Scopus, and CENTRAL databases were searched from inception to June 7, 2023, to identify trials investigating the effect of an LF diet (fat intake ≤30% of energy intake) on the depression score. DATA EXTRACTION: Random-effects meta-analyses were used to estimate pooled summary effects of an LF diet on the depression score (as Hedges g). DATA ANALYSIS: Finding from 10 trials with 50 846 participants indicated no significant change in depression score following LF diets in comparison with usual diet (Hedges g = -0.11; 95% CI, -0.25 to 0.03; P = 0.12; I2 = 70.7% [for I2, 95% CI, 44%, 85%]). However, a significant improvement was observed in both usual diet and LF diets when the content of protein was 15-20% of calorie intake (LF, normal protein diet: n = 5, Hedges g = -0.21, 95% CI, -0.24 to -0.01, P = 0.04, I2 = 0%; usual, normal protein diet: n = 3, Hedges g = -0.28, 95% CI, -0.51 to -0.05, P = 0.01, I2 = 0%). Sensitivity analysis also found the depression score improved following LF diet intervention in participants without baseline depression. CONCLUSION: This study revealed that LF diet may have small beneficial effect on depression score in the studies enrolled mentally healthy participants. Moreover, achieving to adequate dietary protein is likely to be a better intervention than manipulating dietary fat to improve depression scores. However, it is not clear whether this effect will last in the long term. Conducting more studies may change the results due to the low-certainty of evidence. SYSTEMATIC REVIEW REGISTRATION: CRD42023420978 (https://www.crd.york.ac.uk/PROSPERO).

Effects of omega-3 supplementation on serum albumin, pre-albumin and the CRP/albumin ratio in hospitalized patients: a systematic review and meta-analysis.

CONTEXT: Low serum albumin and pre-albumin concentrations are associated with edema, infection, thrombosis, heart failure, and mortality. OBJECTIVE: This comprehensive systematic review and meta-analysis of clinical trials was conducted to summarize the available findings on the impact of omega-3 supplementation on albumin, pre-albumin, and the C-reactive protein/albumin ratio in hospitalized patients. DATA SOURCES: PubMed, Web of Science, Scopus, and Google Scholar databases were searched from January 1990 to October 2021. DATA EXTRACTION: Extracted data from 50 randomized controlled trials (RCTs) with a total number of 3196 participants were analyzed using the random-effects model. The dose-dependent effect was also evaluated. DATA ANALYSIS: Oral omega-3 supplementation significantly increased serum albumin concentrations in patients with cancer (weighted mean difference [WMD]: 0.19; 95% CI: 0.05, 0.33, P= 0.006), patients on dialysis (WMD: 0.14; 95% CI: 0.01, 0.28, P= 0.042), and those with hypoalbuminemia (WMD: 0.38; 95% CI: 0.03, 0.72, P = 0.033); however, there was no significant effect among patients with gastrointestinal or hepatologic diseases. Moreover, each 1000 mg/day increase in oral omega-3 supplementation resulted in elevated serum albumin levels in cancer patients (WMD: 0.15; 95% CI: 0.07, 0.24, P < 0.001). In addition, a favorable effect of oral omega-3 supplementation on pre-albumin levels was observed among patients with cancer (WMD: 33.87; 95% CI: 12.34, 55.39, P = 0.002). A similar significant effect of parenteral omega-3 supplementation on pre-albumin concentrations was seen among those with gastrointestinal and hepatologic diseases as well (WMD: 23.30; 95% CI: 13.58, 33.03, P < 0.001). No significant effect of oral omega-3 supplementation on the CRP/albumin ratio was found. CONCLUSIONS: Overall, omega-3 fatty acids supplementation resulted in a favorable change in serum albumin and pre-albumin concentrations in hospitalized patients. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42021285704.

The Effect of Mediterranean Diet on Body Composition, Inflammatory Factors, and Nutritional Status in Patients with Cachexia Induced by Colorectal Cancer: A Randomized Clinical Trial.

BACKGROUND: Along with high calorie and high protein diet, a new comprehensive dietary approach is needed to control cachexia caused by cancer and its related outcomes. This study was done to evaluate the effect of a Mediterranean diet on body composition, nutritional status, and inflammatory markers among cancer cachexia patients. METHODS: In this randomized clinical trial, 46 patients with colorectal cancer-induced cachexia were included. After randomization, 23 patients were allocated to the intervention group (Mediterranean diet) and 23 to the control group (nutritional counseling for weight gain and prevention of weight loss in cancer patients). The primary outcome including muscle health, nutritional status, and inflammatory markers along with secondary outcomes such as quality of life, and serum proteins were evaluated at the start and the eighth week of the study. Statistical analysis was performed according to the intention-to-treat concept. To compare changes in dependent variables between the 2 groups, analysis of covariance (ANCOVA) was performed. RESULTS: After adjustment for the baseline values, age, sex, and supplements use, in the Mediterranean diet group mean of weight (P < .001), lean body mass (P = .001), fat mass (P = .002), and muscle strength (P < .001) were significantly increased compared to the control group. Regarding inflammatory markers, the mean serum level of tumor necrosis factor-alpha (TNF-α) (P < .001), high sensitive-C-reactive protein (hs-CRP) (P = .01) and Interleukin 6 (IL-6) (P < .001) were significantly improved in the Mediterranean diet group. Moreover, in the Mediterranean diet group, the score for global health status (P = .02) and physical performance score (P < .001) were significantly increased. CONCLUSION: It appears that the implementation of the Mediterranean diet might be a strategy to improve nutritional status, quality of life, inflammatory markers, and body composition in patients with colorectal cancer cachexia. TRIAL REGISTRATION: Iranian Registry of Clinical Trials (www.irct.ir); ID: IRCT20211027052884N1.

Association between animal protein sources and risk of neurodegenerative diseases: a systematic review and dose-response meta-analysis.

CONTEXT: Current findings about the differential effects of various sources of dietary animal protein on the risk of neurodegenerative diseases are contradictory. OBJECTIVE: The current meta-analysis was conducted to investigate the associations between intake of dietary animal protein sources and the risk of neurodegenerative diseases. DATA SOURCES: PubMed, Scopus, Web of Science, and Google Scholar databases were searched systematically until October 2021. DATA EXTRACTION: Prospective cohort studies exploring the association between consumption of animal protein sources and risk of neurodegenerative diseases in the general population were included. Among 10 571 identified studies, 33 prospective cohort studies met the eligibility criteria. DATA ANALYSIS: Dietary fish consumption was associated with a reduced risk of Alzheimer's disease (RR = 0.75; 95%CI, 0.57-0.97), dementia (RR = 0.84; 95%CI, 0.75-0.93), and cognitive impairment (RR = 0.85; 95%CI, 0.81-0.95). The risk of developing Parkinson's disease was significantly higher among those in the highest vs the lowest intake categories of total dairy (RR = 1.49; 95%CI, 1.06-2.10) and milk (RR = 1.40; 95%CI, 1.13-1.73). Moreover, dietary intake of total dairy (RR = 0.89; 95%CI, 0.80-0.99), total meat (RR = 0.72; 95%CI, 0.57-0.90), and poultry (RR = 0.82; 95%CI, 0.68-0.99) was significantly associated with a lower risk of cognitive impairment. A linear dose-response meta-analysis revealed that each 200-g increase in total daily dairy intake was associated with an 11% higher risk of Parkinson's disease and a 12% lower risk of cognitive impairment. Furthermore, there was a strong linear association between fish consumption and reduced risk of dementia. CONCLUSION: Dairy consumption is associated with an increased risk of Parkinson's disease, but a higher intake of fish may be associated with lower risk of neurodegenerative disease. Future well-controlled, randomized clinical trials are essential to validate the present findings. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42021281887.

The association of plant-based dietary pattern with general and abdominal obesity: a large cross-sectional study.

Purpose: Only a few studies have studied the association between plant-based dietary index (PDI) and the prevalence of obesity. The purpose of this study was to investigate the association between PDI and the prevalence of general and abdominal obesity in a large sample of Iranian adults. Methods: The current cross-sectional study was performed from 2010 to 2012 in Isfahan, Iran. This study comprised 6,724 adults between the ages of 18 and 55. We analyzed data from 6,724 participants who were classified as having general obesity and 5,203 individuals who were classified as having abdominal obesity. Dietary intake was assessed using a validated food frequency questionnaire. We determined the PDI by assigning plant foods positive scores and animal foods negative values using the method of Satija et al. General obesity was defined as having a body mass index (BMI) greater than 30 kg/m2, whereas abdominal obesity was classified as having a waist circumference (WC) greater than 88 cm for women and 102 cm for men. Data was examined using Chi-squared test and the analysis of variance (ANOVA and ANCOVA). Multivariable binary logistic regression analyses were performed to evaluate the association between PDI and risk of general as well as abdominal obesity. Results: The mean age of the study participants was 36.8 ± 8.08 years, and 57% of them were female. General obesity prevalence was 9.6%, while abdominal obesity was 26.8%. In all the unadjusted and multivariable adjusted models of the total population, there was no significant association between highest vs. lowest adherence to the PDI and general obesity or abdominal obesity. No significant association was found when men and women were analyzed separately as well. Conclusion: In the present study, no association was observed between PDI and general and abdominal obesity in the Iranian adult population.

The association between dietary intakes of zinc, vitamin C and COVID-19 severity and related symptoms: A cross-sectional study.

BACKGROUND: The Coronavirus disease 2019 (COVID-19) pandemic has had a devastating impact on health systems, food supplies, and population health. This is the first study to examine the association between zinc and vitamin C intakes and the risk of disease severity and symptoms among COVID-19 patients. METHODS: This cross-sectional study included 250 recovered COVID-19 patients aged 18-65 years from June to September 2021. Data on demographics, anthropometrics, medical history, and disease severity and symptoms were collected. Dietary intake was evaluated using a web-based, 168-item food frequency questionnaire (FFQ). The severity of the disease was determined using the most recent version of the NIH COVID-19 Treatment Guidelines. Using multivariable binary logistic regression, the association between zinc and vitamin C intakes and the risk of disease severity and symptoms in COVID-19 patients was evaluated. RESULTS: The mean age of participants in this study was 44.1 ± 12.1, 52.4% of them were female, and 46% had a severe form of the disease. Participants with higher zinc intakes had lower levels of inflammatory cytokines, such as C-reactive protein (CRP) (13.6 vs. 25.8 mg/l) and erythrocyte sedimentation rate (ESR) (15.9 vs. 29.3). In a fully adjusted model, a higher zinc intake was also associated with a lower risk of severe disease (OR: 0.43; 95% CI: 0.21, 0.90, P-trend = 0.03). Similarly, participants with higher vitamin C intakes had lower CRP (10.3 vs. 31.5 mg/l) and ESR serum concentrations (15.6 Vs. 35.6) and lower odds of severe disease after controlling for potential covariates (OR: 0.31; 95% CI: 0.14, 0.65, P-trend = <0.01). Furthermore, an inverse association was found between dietary zinc intake and COVID-19 symptoms, such as dyspnea, cough, weakness, nausea and vomiting, and sore throat. Higher vitamin C intake was associated with a lower risk of dyspnea, cough, fever, chills, weakness, myalgia, nausea and vomiting, and sore throat. CONCLUSION: In the current study, higher zinc and vitamin C intakes were associated with decreased odds of developing severe COVID-19 and its common symptoms.

Vitamin D status is associated with inflammatory biomarkers and clinical symptoms in patients with knee osteoarthritis.

BACKGROUND AND AIM: The association between vitamin D status and osteoarthritis (OA) and bone remodeling has been shown previously. The present study was conducted to determine the association between vitamin D status and inflammatory biomarkers and clinical symptoms in patients with knee OA. METHODS: This case-control study was performed on 124 subjects with mild to moderate knee OA and 65 healthy controls. Demographic data was collected from all participants at baseline. We used Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC Index) for evaluating the severity of clinical symptoms in these patients. Serum levels of vitamin D as well as markers of inflammation including interleukin 1-ß (IL-1ß), interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor-alpha (TNF-α), high-sensitivity C-reactive protein (hs-CRP), and nuclear factor k-B (NF-κB) p65 were evaluated for each participant. RESULTS: The results of the present study showed that patients with knee OA had lower levels of vitamin D and higher levels of IL-1ß, TNF-α, hs-CRP, and NF-кB p65 compared with healthy controls (P < 0.0001). The levels of IL-1ß, TNF-α, and NF-кB p65 in knee OA patients with vitamin D insufficiency were significantly higher compared with the knee OA patients with sufficient vitamin D (P < 0.05). Based on the linear regression analysis, serum vitamin D levels were inversely correlated with IL-1ß, TNF-α, hs-CRP, and NF-кB p65 levels (P < 0.0001). Patients with sufficient vitamin D levels had lower total and physical function WOMAC scores compared with patients with vitamin D insufficiency (P = 0.011 and P = 0.010, respectively). CONCLUSION: The results suggest a strong link between vitamin D deficiency and increased inflammatory biomarkers as well as increased severity of clinical symptoms in knee OA patients.

Caffeine, Coffee, Tea and Risk of Rheumatoid Arthritis: Systematic Review and Dose-Response Meta-analysis of Prospective Cohort Studies.

OBJECTIVE: Prospective cohort studies on coffee, tea and caffeine in relation to the risk of rheumatoid arthritis (RA) have shown conflicting results. The aim of this study was to conduct a dose-response meta-analysis of cohort studies on the association between dietary caffeine, different types of coffee and tea consumption and the risk of RA. METHODS: PubMed/Medline, Scopus and EMBASE were searched up to July 2021 to identify relevant studies that had considered different types of coffee (caffeinated or decaffeinated), tea or caffeine exposure with RA as the main, or one of the, outcome(s). Two authors independently screened 742 publications. Finally, five prospective cohort studies were included in our meta-analysis. Pooled relative risks (RRs) were calculated by using a fixed-effects model. We also performed linear and non-linear dose-response analyses to examine the dose-response relations. RESULTS: Comparing extreme categories, we found a positive, significant association between coffee (RR: 1.30; 95% CI: 1.04-1.62; I 2 = 0%, n = 5) and decaffeinated coffee (RR: 1.89; 95% CI: 1.35-2.65; I 2 = 38.1%, n =3) consumption and risk of RA. One additional cup of coffee consumed per day was associated with an increased risk of RA by 6% (95% CI: 1.02-1.10; I 2 = 0%). This increase in the risk of RA for one cup/d of decaffeinated coffee was 11% (95% CI: 1.05-1.18; I 2 = 38). No significant association was observed between caffeinated coffee, tea or caffeine intake and the risk of RA. CONCLUSION: We found that a higher intake of coffee and decaffeinated coffee was associated with increased risk of RA. No significant association between caffeinated coffee, tea or caffeine intake and the risk of RA was observed. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=227665, identifier: CRD42021227665.

Associations of Total Protein or Animal Protein Intake and Animal Protein Sources with Risk of Kidney Stones: A Systematic Review and Dose-Response Meta-Analysis.

We conducted the present systematic review and meta-analysis to evaluate the association of total protein, animal protein, and animal protein sources with risk of kidney stones in the general population. A literature search was performed in PubMed/Medline, Scopus, and EMBASE up to July 2021. We assessed the credibility of evidence based on NutriGrade scoring system. A total of 14 prospective cohort studies were included. A positive association was observed between higher intake of nondairy animal protein (RR: 1.11; 95% CI: 1.03, 1.20; I2 = 0%, n = 4), total meat and meat products (RR: 1.22; 95% CI: 1.09, 1.38; I2 = 13%, n = 3), and processed meat (RR: 1.29; 95% CI: 1.10, 1.51; I2 = 0%, n = 2) with risk of kidney stones. There was an inverse association between higher intake of dairy protein and risk of kidney stones (RR: 0.91; 95% CI: 0.84, 0.99; I2 = 0%, n = 4). Moreover, each 100-gincrement of red meat intake was significantly associated with increased risk of kidney stones (RR: 1.39; 95% CI: 1.13, 1.71). According to the NutriGrade scoring system, the credibility of evidence for most of the exposures was rated as low. We found some kind of publication bias in the association of animal protein intake and risk of kidney stones, according to Egger's and Begg's tests. In the sensitivity analysis of processed meat as well as dairy consumption with risk of kidney stones we observed in each individual analysis, 1 study changed the overall estimate. Further observational studies are needed to confirm the present results. The protocol of the present study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42021230125: https://www.crd.york.ac.uk/PROSPERO).

The effect of probiotic cheese consumption on inflammatory and anti-inflammatory markers, disease severity, and symptoms in patients with rheumatoid arthritis: study protocol for a randomized, double-blind, placebo-controlled trial.

BACKGROUND: In recent decades, several studies have shown changes in the intestinal microflora among patients with rheumatoid arthritis (RA). Therapeutic measures using probiotics have shown favorable effects on the recovery of these patients. However, most studies have used probiotic supplements. In this study, we aimed to investigate the effect of probiotic cheese consumption on inflammatory and anti-inflammatory factors, disease severity, and symptoms in these patients. METHODS: This study is a randomized, double-blind clinical trial, in which forty patients with mild to moderate severity of RA will be randomly allocated to receive either 30 g/day probiotic cheese (n = 20) or only low-salt and low-fat cheese without any added probiotic (n = 20) for 12 weeks. Assessment of anthropometric measures and biochemical indicators, including serum concentrations of high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10), will be done at the study baseline and end of the trial. In addition, disease severity and disability will be assessed by DAS-28 and the HAQ-DI questionnaire, respectively. DISCUSSION: Diet is the leading environmental factor affecting the gut microbiota. A prebiotic-rich diet and probiotics might be beneficial in this regard. To the best of our knowledge, the effect of probiotic supplements on inflammation in these patients has widely been assessed; however, there is only one study that examined the effect of probiotic-containing food in these patients. Further studies are needed to investigate the effect of probiotic-containing foods on inflammatory markers and symptoms in patients with RA. TRIAL REGISTRATION: Iranian Registry of Clinical Trials IRCT20201120049449N1 . Registered on 14 February 2021.

Inflammatory cytokines and sarcopenia in Iranian adults-results from SARIR study.

Some studies suggested the effects of inflammatory cytokines in reducing muscle mass and muscle strength and, performance. This study aimed to compare pro-inflammatory cytokines in sarcopenic and non-sarcopenic subjects. 120 men and women were selected out from the cross-sectional study 'sarcopenia and its determinants among Iranian elders' (SARIR). Sarcopenia was defined based on the first 'European Working Group on sarcopenia in older people' (EWGSOP1) guidelines. A fasting blood sample was taken from each participant to measure serum high-sensitivity C-reactive protein (hs-CRP), Interleukin 6 (IL-6), and tumor necrosis factor α (TNFα). A total of 120 participants were included in this study. Mean age was 66.7 ± 7.7 years and mean body mass index (BMI) was 27.3 ± 4.2 kg/m2. Forty participants had the criteria of EWGSOP1 sarcopenia. A statistically significant difference was seen between normal and abnormal groups of muscle strength in hs-CRP (P-value = 0.04). Furthermore, we did not observe any remarkable association between inflammatory biomarkers including IL-6 (OR 1.15; 95% CI 0.31-4.28), TNF-α (OR 0.68; 95% CI 0.17-2.77), and hs-CRP (OR 2.39; 95% CI 0.87-6.55) and the presence of sarcopenia even after controlling for plausible confounders. We found that inflammatory biomarkers level was not associated with odds of sarcopenia. The lack of correlation between inflammatory cytokines and sarcopenia could be due to the participants' age and genetics. Future studies are required to confirm these findings.

Zinc status in attention-deficit/hyperactivity disorder: a systematic review and meta-analysis of observational studies.

Previous studies regarding the zinc status in attention-deficit/hyperactivity disorder (ADHD) yielded inconsistent results. Thus, the present meta-analysis was aimed to estimate the association between hair and serum/plasma zinc levels and ADHD. Online databases of Medline, EMBASE, and Scopus were searched up to October 2020 with no limitation in time and language. Weighted mean differences (WMDs) of hair and serum/plasma zinc levels were calculated using a random-effects model. Overall, 22 articles with 1280 subjects with ADHD and 1200 controls were included. The pooled effect size indicated that serum/plasma zinc levels in subjects with ADHD were not statistically different than their controls (WMD = - 1.26 µmol/L; 95% CI - 3.72, 1.20). Interestingly, the exclusion of one study from the analysis showed that people with ADHD significantly have lower circulating levels of zinc compared to their controls (WMD: - 2.49 µmol/L; 95% CI - 4.29, - 0.69). Also, the pooled effect size indicated that hair zinc levels in cases with ADHD were not statistically different than their controls (WMD = - 24.19 µg/g; 95% CI - 61.80, 13.42). Present meta-analysis raises the possibility that subjects with ADHD are prone to have declined levels of zinc levels. Based on current findings, screening the zinc levels in subjects with ADHD could be reasonable. Further well-designed studies are needed to clarify the role of zinc in the etiology of ADHD.

Fruit and vegetable intake and risk of frailty: A systematic review and dose response meta-analysis.

PURPOSE: This systematic review and dose-response meta-analysis of observational studies was conducted to summarize available findings on the association between fruits and vegetables (FVs) consumption and risk of frailty. METHODS: Online databases including Medline, Scopus, and Embase were searched to detect related publications up to February 2021. Study selection and data extraction were performed by two investigators working in parallel. In most included studies, frailty was defined according to the Fried criteria. Overall, 14 articles with 18,616 subjects with frailty and 101,969 controls were included. To combined data, a random effect model was used. Dose-response associations were also evaluated. RESULTS: Fourteen studies (10 cohorts and four cross-sectional) were included. Pooled effect size for the highest versus lowest category of FVs consumption showed an inverse association with risk of frailty (RR cohort = 0.65; 95% CI: 0.50-0.84; I2 = 81%, n = 7). Every one serving (200 g) per day increment in FVs intake was associated with a 14% lower risk of frailty. The risk of frailty decreased linearly up to FVs consumption of 3.5 servings/d, with flattening the curve at higher intake. Pooled analysis regarding fruits and vegetables separately did not indicate a significant association with the risk of frailty. Indeed, the results of the meta-analysis correspond only to the cohort studies. Based on the NutriGrade score, the quality of evidence for a protective effect of FV on frailty was "moderate". CONCLUSIONS: FVs consumption was associated with a decreased risk of frailty. Further large-scale prospective cohort studies are needed to reach more confident conclusions.

A systematic review and meta-analysis of observational studies on the association between animal protein sources and risk of rheumatoid arthritis.

OBJECTIVE: The aim of this study was to investigate the linear and nonlinear dose-response associations of animal-based dietary protein intake and risk of developing rheumatoid arthritis (RA). METHODS: A systematic search of MEDLINE, Scopus and Embase was conducted up to October 2020. Observational studies that report risk estimates of RA for animal-based protein consumption were included. We calculated pooled relative risks (RRs) by using a random-effects model. Linear and non-linear dose-response analyses were performed to examine the dose-response relations between animal-based protein consumption and RA. RESULTS: Seven cohort studies (n = 457,554) with 3545 incident cases and six case-control studies with 3994 cases and 5252 controls were identified. Highest compared with the lowest category of fish consumption was inversely associated with risk of RA (RR: 0.89; 95% CI, 0.80 to 0.99; I2 = 0%, n = 10). Also, a 100 g/day increment in fish intake was associated with a 15% decreased risk of RA. Dose-response analysis showed a modest U-shaped association between fish consumption and incidence of RA, with the lowest risk at a fish intake of 20-30 g/day (Pnon-linearity = 0.04). We found no significant association between consumption of red meat, poultry or dairy and the risk of RA. CONCLUSION: The present study revealed a significant reverse association between fish consumption and risk of RA. While we observed no association between red meat, dairy or poultry consumption and risk of RA. Further well-designed prospective studies are needed to support our findings.