Effects of nutrition on metabolic and endocrine outcomes in women with polycystic ovary syndrome: an umbrella review of meta-analyses of randomized controlled trials.

CONTEXT: Numerous meta-analyses have been conducted on the effects of nutritional interventions on various health outcomes in women with polycystic ovary syndrome (PCOS). However, the strength of the evidence and its clinical significance are unclear. OBJECTIVE: This umbrella review aimed to summarize the effects of nutritional interventions on women with PCOS and assess the strength of the evidence. DATA SOURCES: PubMed, Scopus, and Web of Science were searched from inception until March 17, 2021. DATA EXTRACTION: Meta-analyses of randomized clinical trials (RCTs) that examined the impact of dietary modifications or supplementations on women with PCOS were selected. Data extraction, quality assessments of the meta-analyses, and evaluation of the strength of the evidence were conducted independently by 2 investigators and confirmed by a third. DATA ANALYSIS: Twenty-eight RCT meta-analyses were included, reporting 40 different outcomes. Lower carbohydrate, Dietary Approaches to Stop Hypertension, or lower glycemic index/load diets in women with PCOS significantly improved some anthropometric and metabolic characteristics (with very low to low certainty). Probiotics/synbiotics reduced fasting plasma glucose, fasting insulin (FI), and homeostasis model assessment-estimated insulin resistance (HOMA-IR) (with moderate to high certainty). Curcumin supplementation decreased fasting plasma glucose, FI, and HOMA-IR (with moderate certainty). Fish oil supplementation decreased FI and HOMA-IR, and omega-3 reduced triglycerides (with moderate certainty). There were also improvements in FI after taking vitamin D or inositol supplements (with moderate certainty). Supplementation with fish oil increased adiponectin (with high certainty), and probiotics/synbiotics reduced total testosterone (with moderate certainty). In subfertile women with PCOS, inositol increased the ovulation rates (with moderate certainty). CONCLUSION: There was no high-certainty evidence that diets alone in women with PCOS improved health or reproductive outcomes. Supplementation with vitamin D, probiotics/synbiotics, omega-3, inositol, and curcumin showed favorable effects on some metabolic outcomes. Probiotics/synbiotics possibly reduces total testosterone, and inositol stimulates ovulation in women with PCOS. REGISTRATION: PROSPERO registration no. CRD42021251496.

Visceral adiposity-related dietary patterns and the risk of cardiovascular disease in Iranian adults: A population-based cohort study.

Background: Visceral obesity is a significant predictor of cardiovascular disease (CVD). Diet may associate with CVD risk through its effects on visceral adiposity. This study aimed to find dietary patterns (DPs) related to indicators of visceral adiposity and to determine whether the DPs were associated with CVD risk. Methods: This prospective study included 2,496 participants of the Tehran Lipid and Glucose Study (TLGS) without CVD, who were followed from the third study examination (2005-2008; baseline) to March 2018. DPs at baseline were determined using reduced rank regression (RRR) and partial least squares regression (PLS). The response variables were age and BMI-adjusted waist circumference (WC) and age-adjusted visceral adiposity index (VAI). Results: Two and three DPs were retained with RRR and PLS, respectively. The first patterns of each method were mainly characterized by adjusted-WC (RRR: 10.8%, PLS: 8.6%); none of them were associated with CVD risk. The second pattern of RRR and the third pattern of PLS were mainly explained by adjusted-VAI (RRR: 3.3, PLS: 2.1%). After adjusting for CVD risk factors, the hazard ratios [95% confidence intervals (CI)] for CVD in the second and third tertiles of the RRR-pattern 2 were 1.76 (1.15, 2.69) and 1.55 (1.00, 2.43) vs. the first tertile (p-trend: 0.058). This pattern had high positive loadings for non-leafy vegetables, pickled vegetables, fried vegetables, and bread and high negative loadings for eggs, cakes, butter, jam-honey, red meat, poultry, fish, juice, non-fermented dairy, and fruits. Per one SD increase in PLS-pattern 3 score, the risk of CVD was 19% higher (95%CI = 3-38%). This positive association was also observed across tertiles of the pattern (p-trend: 0.032). This pattern was characterized by high intakes of leafy vegetables, non-leafy vegetables, organ meat, soft drinks, olive oil, pickled vegetables, fried vegetables, and bread and low intakes of biscuits, cakes, butter, eggs, and non-fermented dairy. Conclusion: For each of the RRR and PLS approaches, a visceral-related DP that was positively linked to CVD was identified. These two patterns had a modest correlation. The pattern generated by PLS explained more variations in food groups and offered stronger evidence of association with CVD than the RRR-derived pattern.

Healthy Dietary Pattern Reduces Risk of Gallstones: Results of a Case-Control Study in Iran.

Background: Nutrition-related factors have been of great interest as one of risk factors of biliary stones. This study evaluated the association of dietary patterns with biliary stone among Iranians. Methods: This is a hospital-based case-control study, which was conducted in a general hospital in Tehran, Iran. A total of 110 patients with gallstone or common bile duct (CBD) stone confirmed by Ultrasonography within the last 6 months before collecting data were recruited. Controls were age-matched patients admitted to the other wards of the same hospital for a broad spectrum of disorders including traumas and orthopedic conditions, or elective surgeries, or throat/ear/nose disease and had no gallbladder disorders, participated in this study. We used a valid and reliable food frequency questionnaire to assess dietary intakes of participants. Dietary patterns were determined by factor analysis. Results: By design, age was similar in both groups (57.66 ± 16.39 years vs. 56.00 ± 10.64 years in cases and controls, respectively). Two dietary patterns were extracted; "Unhealthy" (high consumption of artificial juice, processed meats, refined grains, sweets and desserts, pickles, snacks, and red meats), and "Healthy" (high consumption of vegetable oils, vegetables, fruits, fish, legumes, and nuts, as well as low consumption of hydrogenated fats and salt). Participants in the highest tertile of "Healthy" dietary pattern were significantly less likely to have the gallstones disease (OR: 0.33, 95% CI = 0.120.89) compared to the reference group (low tertile of "Healthy" dietary pattern) (P = 0.02). Conclusions: High consumption of vegetable oils, vegetables, fruits, fish, legumes, and nuts, as well as low consumption of hydrogenated fats and salt in context of healthy dietary pattern are inversely associated with risk of gallstones.

Red and Processed Meat Intake in Relation to Non-Alcoholic Fatty Liver Disease Risk: Results from a Case-Control Study.

Data on the association between dietary red meat intake and non-alcoholic fatty liver disease (NAFLD) are limited. We designed this case-control study to determine the association between red and processed meat consumption and risk of NAFLD in Iranian adults. A total of 999 eligible subjects, including 196 NAFLD patients and 803 non-NAFLD controls were recruited from hepatology clinics in Tehran, Iran. A reliable and validated food frequency questionnaire was used to evaluate the red and processed meat intakes. The analyzes performed showed that in an age- and gender-adjusted model, patients with the highest quartile of red meat intake had an approximately three-fold higher risk of NAFLD than those with the lowest quartile of intake (odds ratio [OR], 3.42; 95% confidence interval [CI], 2.16-5.43; p value < 0.001). Moreover, patients in the highest quartile of processed meat intake had a 3.28 times higher risk of NAFLD, compared to the lowest quartile(OR, 3.28; 95% CI, 1.97-5.46; p value < 0.001).Both these associations remained significant by implementing additional adjustments for body mass index, energy intake, dietary factors, diabetes, smoking, and physical activity (OR, 3.65; 95% CI, 1.85-7.18; p value < 0.001 and OR, 3.25; 95% CI, 1.57-6.73; p value = 0.002, respectively).Our findings indicate that both red and processed meat intakes are related to the increased odds of NAFLD; however, prospective studies are needed to confirm these results.

Body mass index and risk of Parkinson, Alzheimer, Dementia, and Dementia mortality: a systematic review and dose-response meta-analysis of cohort studies among 5 million participants.

Objective: Inconsistent results regarding the association between the Body Mass Index (BMI) and brain disorders have been reported. We performed this study to investigate the association between BMI and risk of Parkinson, Alzheimer, Dementia and Dementia-mortality.Methods: A systematic search was conducted up to April 2019 in MEDLINE/PubMed, SCOPUS, and Cochrane Library. Results pooled with random-effects model.Results: Totally, 29 articles which were included in this study with4,978,621 participants. The pooled HR for Parkinson's in the underweight person was 1.20 (95%CI1.10-1.30). The pooled HR for dementia in underweight and overweight category was 1.23 (95%CI = 1.05-1.45) and 0.88 (95%CI = 0.83-0.94), respectively. There is not any significant relation between each categories of BMI and Alzheimer disease. The pooled HR for dementia in underweight and overweight category was 1.36 (95%CI = 1.14-1.63) and 0.81 (95%CI = 0.49-1.33), respectively. The non-linear association between BMI and risk of Dementia-mortality was significant (p = 0.001,Coeff = 0.003).Conclusion: This study highlights underweight related to increase incidence of Parkinson, Dementia, and Dementia mortality but no on Alzheimer disease.

Effects of vitamin K2 supplementation on atherogenic status of individuals with type 2 diabetes: a randomized controlled trial.

BACKGROUND: This study was aimed to examine the effects of vitamin K2 supplementation on atherogenic status, assessed by insulin resistance (IR)-related indexes, in patients with type 2 diabetes mellitus (T2DM). METHODS: In this double-blind, controlled trial, 68 patients with T2DM on the oral glucose-lowering medications were randomly allocated into two groups receiving daily intakes of 360 µg MK-7 or placebo for 12 weeks. Eight different IR-related indexes were calculated at the baseline and end of the trial. RESULTS: At the end of the study, atherogenic coefficient (mean ± SD: - 0.21 ± 0.45 vs. 0.02 ± 0.43; p = 0.043), triglyceride-glucose index (8.88 ± 0.55 vs. 9.23 ± 0.69; p = 0.029), and atherogenic index of plasma (0.37 ± 0.27 vs. 0.51 ± 0.24; p = 0.031) were significantly lower in the vitamin K2 group, compared to the placebo. However, after accounting for their baseline values, the differences were no more significant. No significant differences were observed in Castelli's Ӏ and ӀӀ risk indexes, the ratio of triglycerides to high-density lipoprotein cholesterol, lipoprotein combine index, and the metabolic score for insulin resistance index between the two groups at the end of the study. CONCLUSIONS: Daily intakes of 360 µg vitamin K2 in the form of MK-7 for 12 weeks could not improve the IR-related indexes of Cardiovascular Diseases risk. TRIAL REGISTRATION: The trial was registered on Iranian Registry of Clinical Trials registry (Trial ID. IRCT20190824044592N1) on 22 December 2019. The record can be found at https://en.irct.ir/trial/41728 .

Glycemic control improvement in individuals with type 2 diabetes with vitamin K2 supplementation: a randomized controlled trial.

PURPOSE: This study aimed to investigate the effects of vitamin K2 supplementation in the form of menaquinone-7 (MK-7) on glucose, insulin, and lipid metabolism in patients with type 2 diabetes mellitus (T2DM). METHODS: In this double-blinded, placebo-controlled, randomized trial, 68 insulin-independent people with diabetes received either 180 µg MK-7 twice a day or placebo for 12 weeks. We assessed fasting plasma glucose (FPG) and insulin concentrations (primary outcomes), glycated hemoglobin (HbA1c), insulin sensitivity indices, and lipid profiles (secondary outcomes) at baseline and end of the trial. RESULTS: At the end of the trial, FPG (effect size (ES) = - 0.68; p-adjusted = 0.031) and HbA1c (ES = - 0.36; p-adjusted = 0.004) were significantly lower in the vitamin K2 group compared with the placebo at the end of the trial. The number of participants achieved the target levels of glycemic control based on FPG, and HbA1c concentrations were significantly higher in the vitamin K2 group compared to the placebo group. Insulin concentrations (ES = - 0.29; p = 0.019) and homeostatic model assessment for insulin resistance (HOMA-IR) significantly decreased in the vitamin K2 group (ES = - 0.29; p = 0.019) compared to baseline, but their values were not significantly different compared to the placebo group at the end of the trial. No significant variation was observed in lipid profiles. CONCLUSION: Daily intake of 360 µg Vitamin K2 in the form of MK-7 for 12-weeks reduces FPG and HbA1c in patients with T2DM but does not have a lipid-lowering effect.

Relationship between body mass index, risk of venous thromboembolism and pulmonary embolism: A systematic review and dose-response meta-analysis of cohort studies among four million participants.

BACKGROUND: The relationship between body mass index (BMI) and risk of venous thromboembolism (VTE) and pulmonary embolism (PE) is a controversial issue. This dose-response meta-analysis was performed to investigate the association between BMI and risk of VTE and PE incidence based on cohort studies. METHOD: A comprehensive systematic search was conducted up to August 2019 in MEDLINE/PubMed, SCOPUS, and Cochrane. DerSimonian and Laird random-effects models were run to estimate combined hazard ratios (HRs) with 95% confidence intervals (CIs). Dose-response analysis was also carried out based on BMI values. RESULTS: Eleven articles with 16 arms and 3,910,747 participants were eligible for inclusion in this systematic review and meta-analysis. Pooled results showed a positive association between BMI and risk of VTE in the obese participants compared to participants classified in the normal BMI category (HR: 1.62, 95% CI: 1.29-2.04, I2 = 95%). Furthermore, results showed a significant association between lower BMI (underweight versus normal BMI category) and reduced risk of PE (HR: 0.80, 95% CI: 0.70-0.92, I2 = 9%) and higher risk of PE in obese versus normal BMI participants (HR: 2.24, 95% CI: 1.93-2.60, I2 = 0%). There was a significant linear relationship between BMI and risk of VTE (p < 0.001) and PE (p < 0.001). CONCLUSIONS: This systematic review and dose-response meta-analysis with 3,910,747 participants highlights obesity as a significant risk factor related to the incidence of VTE and PE.

Serum uric acid and risk of cardiovascular mortality: a systematic review and dose-response meta-analysis of cohort studies of over a million participants.

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of death worldwide. Some studies have suggested anassociation between serum uric acid levels and cardiovascular mortality; however, the results have not been summarized in a meta-analysis. METHODS: A comprehensive search of all related studies until April 2018was performed in MEDLINE/PubMed and Scopus databases DerSimonianand Laird random-effects models were used to combine hazard ratios (HRs) with 95% confidence intervals (CIs). Dose-response analysis was also carried out. RESULTS: Thirty-two studies containing forty-four arms with 1,134,073 participants reported association between uric acid and risk of CVD mortality were included in our analysis. Pooled results showed a significant positive association between uric acid levels and risk of CVD mortality (HR 1.45, 95% CI 1.33-1.58, I2 = 79%). Sub-group analysis showed this relationshipwasstronger in women compared to men. Moreover, there was a significant non-linear association between uric acid levels and the risk of CVD mortality (r = 0.0709, p = 0.001). CONCLUSION: Our analysis indicates a positive dose-response association between SUA and CVD mortality risk.