Nutrition and health

Objectives:
Are serum albumin concentrations lower in patients with stable COPD compared to non-COPD controls?  

Study design:
This review article included 26 studies with a total of 2,554 COPD patients (74% males) and 2,055 non-COPD controls (63% males).
Overall, the mean age of participants across all studies was 61.7 years in COPD patients and 64.6 years in controls (patients without COPD).
Almost all (24 out of 26) were prospective cohort studies.

The Begg’s [p = 0.04] and Egger’s tests [p = 0.01] showed a significant publication bias; however, the trim-and-fill analysis found that no study was missing or should be added.

Results and conclusions:
The investigators found pooled results showed that serum albumin concentrations were significantly lower in COPD patients [SMD = -0.50, 95% CI = -0.67 to -0.32, p 0.001, I2 = 85.7%, p 0.001] .
Sensitivity analysis showed that the effect size was not modified when any single study was in turn removed [effect size ranged between -0.44 and -0.52].

The investigators found no significant differences in SMD of serum albumin concentrations between COPD patients with forced expiratory volume in the 1st second (FEV1) 50% and those with FEV1 > 50%.

The investigators concluded that serum albumin concentrations are lower in patients with stable COPD compared to non-COPD controls. This supports the presence of a deficit in systemic anti-inflammatory and antioxidant defense mechanisms in COPD.

Original title:
Serum Albumin Concentrations in Stable Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis by Zinellu E, Fois AG, […], Pirina P.

Link:
https://www.mdpi.com/2077-0383/10/2/269/htm

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Objectives:
Evidence suggests that vitamin C supplementation could be a potential therapy in type 2 diabetes. However, its effectiveness and evidence quality require further evaluation. Therefore, this review article has been conducted.

Does oral vitamin C supplementation improve glycemic control, cardiovascular risk factors and oxidative stress in people with type 2 diabetes?

Study design:
This review article included 28 RCTs with in totaal 1,574 participants.
RCTs were predominantly short term (6 months) with a small number of participants (n 100).

Results and conclusions:
The investigators found that oral vitamin C supplementation significantly reduced systolic blood pressure [mean difference = -6.27, 95% CI = -9.60 to -2.96 mmHg, p = 0.0002, with moderate evidence certainty].

The investigators found that oral vitamin C supplementation significantly reduced HbA1c levels [mean difference = -0.54%, 95% CI = -0.90 to -0.17, p = 0.004, with very low evidence certainty].

The investigators found that oral vitamin C supplementation significantly reduced diastolic blood pressure [mean difference = -3.77, 95% CI = -6.13 to -1.42 mmHg, p = 0.002, with very low evidence certainty].

The investigators concluded evidence from short-term RCTs suggests that oral vitamin C supplementation may improve glycemic control and blood pressure in people with type 2 diabetes. However, vitamin C supplementation cannot currently be recommended as a therapy until larger, long-term and high-quality trials confirm these findings.

Original title:
Effects of Vitamin C Supplementation on Glycemic Control and Cardiovascular Risk Factors in People With Type 2 Diabetes: A GRADE-Assessed Systematic Review and Meta-analysis of Randomized Controlled Trials by Mason SA, Keske MA and Wadley GD.

Link:
https://pubmed.ncbi.nlm.nih.gov/33472962/

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Find more information/studies on vitamin C, reducing blood pressure and diabetes right here.
 

Objectives:
Taurine plays a pivotal role in regulating glucose and lipid metabolism, blood pressure homeostasis and obesity largely due to its cytoprotective, antioxidant and anti-inflammatory actions. Despite promising data from animal studies in this scenario, the efficacy of taurine supplementation in human studies has been inconsistent. Therefore, this review article has been conducted.

Does taurine supplementation lower blood pressure and improve the lipid profile in patients with liver dysregulation?

Study design:
This review article included 12 RCTs.
Most studies were conducted in patients with liver or metabolic dysregulation (diabetes, hepatitis, fatty liver, obesity, cystic fibrosis, chronic alcoholism and cardiac surgery).
The taurine dosage varied from 0.5 to 6 g/d for 15 days to 6 months.

Results and conclusions:
The investigators found that taurine administration (supplementation) had a significant effect of on systolic blood pressure [WMD = -4.67 mm Hg, 95% CI = -9.10 to -0.25], diastolic blood pressure [WMD = -2.90 mm Hg, 95% CI = -4.29 to -1.52], total cholesterol levels [WMD = -10.87 mg/dL, 95% CI = -16.96 to -4.79] and triglycerides levels [WMD = -13.05 mg/dL, 95% CI = -25.88 to -0.22]. 

The investigators found, however, that taurine administration had no effect on fasting blood glucose [WMD = 0.06 mg/dL], HDL cholesterol [WMD = 0.90 mg/dL], LDL cholesterol [WMD = -6.17 mg/dL], as well as on body mass index [WMD = -0.46 kg/m²] and body weight [WMD = -0.47 kg] as the anthropometric measures.

The investigators concluded that, in patients with liver dysregulation, taurine supplements (0.5 to 6 g/d for 15 days to 6 months) reduce blood pressure and improve the lipid profile by reducing total cholesterol and triglyceride levels.

Original title:
The effects of taurine supplementation on obesity, blood pressure and lipid profile: A meta-analysis of randomized controlled trials by Guan L and Miao P.

Link:
https://pubmed.ncbi.nlm.nih.gov/32871172/

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Find here more information/studies about taurine consumption and lowering blood pressure and cholesterol levels.

The main sources of taurine are animal foods, such as meat, fish and dairy products.

Objectives:
Is fish or omega-3 fatty acids consumption associated with a lower risk of venous thromboembolism (VTE)?

Study design:
This review article included 8 prospective cohort studies.
The follow-up duration ranged from 0.5 to 19 years.
The sample size ranged from 595 to 80,263.
The fish and omega-3 fatty acids consumption was assessed by food-frequency questionnaire (FFQ) in all studies.
The diagnosis of venous thromboembolism was obtained in registered medical record (imaging or autopsy) and food was considered as the source of omega-3 fatty acids in all included studies.
Begg's rank-correlation test showed no evidence of publication bias.

Results and conclusions:
The investigators found the overall multi-variable adjusted RR showed no significant relationship between fish consumption and the risk of venous thromboembolism [RR = 1.02, 95% CI = 0.93 to 1.11, p = 0.709, I2 = 33%, p = 0.176].
The sensitivity analysis showed only minimal changes in magnitude of the pooled RR when any study was excluded from the meta-analysis, suggesting that no individual study had excessive influence on these robust aggregate results.

The investigators found the overall multi-variable adjusted RR showed that omega-3 fatty acids consumption was associated with a lower risk of 11% for venous thromboembolism [RR = 0.89, 95% CI = 0.80 to 0.98, p = 0.024, I2 = 0%, p = 0.469].
The sensitivity analysis showed only minimal changes in magnitude of the pooled RR when any study was excluded from the meta-analysis, suggesting that no individual study had excessive influence on these robust aggregate results.

The investigators found the overall multi-variable adjusted RR showed that omega-3 fatty acids consumption was associated with a lower risk of 55% for recurrent venous thromboembolism [RR = 0.45, 95% CI = 0.25 to 0.81, p = 0.008, I2 = 26.4%, p = 0.244].
Significant because RR of 1 was not found in the 95% CI of 0.25 to 0.81. RR of 1 means no risk/association.

The investigators concluded omega-3 fatty acids consumption is associated with a lower risk of both venous thromboembolism and recurrent venous thromboembolism.

Original title:
Associations of Fish and Omega-3 Fatty Acids Consumption With the Risk of Venous Thromboembolism. A Meta-Analysis of Prospective Cohort Studies by Zhang Y, Ding J, [...],Li Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7793732/

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Venous thromboembolism (VTE) is a condition in which a blood clot forms most often in the deep veins of the leg, groin or arm (known as deep vein thrombosis, DVT) and travels in the circulation, lodging in the lungs (known as pulmonary embolism, PE).

Objectives:
Do melatonin supplements improve sleep quality as assessed by the Pittsburgh Sleep Quality Index (PSQI) in adults with various diseases?

Study design:
This review article included a total of 23 RCTs.

Results and conclusions:
The investigators found that melatonin supplements had significant effects on sleep quality as assessed by the Pittsburgh Sleep Quality Index (PSQI) [WMD = -1.24, 95% CI = -1.77 to -0.71, p = 0.000, I2 = 80.7%, p = 0.000].

The investigators found subgroup analysis based on health status revealed melatonin supplements in subjects with respiratory diseases [WMD = -2.20, 95% CI = -2.97 to -1.44, p = 0.000], metabolic disorders [WMD = -2.74, 95% CI = -3.48 to -2.00, p = 0.000] and sleep disorders [WMD = -0.67, 95% CI = -0.98 to -0.37, p = 0.000] had significant effects on sleep quality.

The investigators concluded the treatment with exogenous melatonin (melatonin supplements) has positive effects on sleep quality as assessed by the Pittsburgh Sleep Quality Index (PSQI) in adults, particularly with respiratory diseases, metabolic disorders, primary sleep disorders; however, not with mental disorders, neurodegenerative diseases and other diseases.

Original title:
Effect of melatonin supplementation on sleep quality: a systematic review and meta-analysis of randomized controlled trials by Fatemeh G, Sajjad M, […], Khadijeh M.

Link:
https://pubmed.ncbi.nlm.nih.gov/33417003/

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Objectives:
Many studies have investigated the association between dietary iron intake and death due to cardiovascular disease (CVD), but the results were inconsistent. Therefore, this review article has been conducted.

Does dietary iron intake increase risk of death due to cardiovascular disease (cardiovascular disease mortality)?

Study design:
This review article included 19 prospective cohort studies including 720,427 participants (46,045 deaths due to cardiovascular disease).

Results and conclusions:
The investigators found when comparing the highest versus lowest level, the highest level of dietary heme iron intake significantly increased risk of death due to cardiovascular disease with 19% [pooled RR = 1.19, 95% CI = 1.01-1.39].

The investigators found every 1-mg/day increase in dietary heme iron intake significantly increased risk of death due to cardiovascular disease with 25% [pooled RR = 1.25, 95% CI = 1.17-1.33].

The investigators found every 1-mg/day increase in dietary heme iron intake significantly increased risk of death due to stroke with 17% [pooled RR = 1.17, 95% CI = 1.04-1.32].

The investigators found the association between dietary iron intake and cardiovascular disease mortality was linear [p nonlinearity > 0.05].

The investigators concluded higher dietary intake of heme iron (at least 1-mg/day) is associated with a greater risk of cardiovascular disease mortality. Therefore, reducing consumption of heme iron may help to prevent premature death due to cardiovascular disease.

Original title:
Dietary iron intake and risk of death due to cardiovascular diseases: A systematic review and dose-response meta-analysis of prospective cohort studies by Han M, Guan L, […], Lu J.

Link:
https://pubmed.ncbi.nlm.nih.gov/32674239/

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Food items of heme iron are:

• Beef or chicken liver
• Beef
• Canned light tuna
• Canned sardines
• Organ meats
• Oysters, clams, mussels
• Poultry

Objectives:
Previous studies lack consistent conclusions as to whether astaxanthin is actually linked to various health benefits as claimed. Therefore, this review article has been conducted.

Is there a causal relationship between astaxanthin consumption and improvements in risk factors for diabetes or cardiovascular disease?

Study design:
This review article included 14 RCTs.

Results and conclusions:
The investigators found that astaxanthin consumption was not associated with FBS, HbA1c, TC, LDL-C, TG, BMI, BW, DBP and SBP.

The investigators found that astaxanthin consumption was associated with an increase in HDL cholesterol levels [WMD = 1.473 mg/dL, 95% CI = 0.319 to 2.627, p = 0.012].

The investigators found that astaxanthin consumption during ≥12 weeks was associated with a decrease in CRP levels [WMD = -0.528 mg/L, 95% CI = -0.990 to -0.066].

The investigators found that >12 mg/day astaxanthin consumption was associated with a decrease in CRP levels [WMD = -0.389 mg/dL, 95% CI = -0.596 to -0.183].

The investigators concluded that astaxanthin consumption is causally associated with an increase in HDL cholesterol levels (good cholesterol) and a decrease in CRP levels for >12 mg/day astaxanthin consumption during ≥12 weeks. Significant associations are not observed for other outcomes.

Original title:
The effects of astaxanthin supplementation on obesity, blood pressure, CRP, glycemic biomarkers, and lipid profile: A meta-analysis of randomized controlled trials by Xia W, Tang N, [...], Zhu Y.

Link:
https://pubmed.ncbi.nlm.nih.gov/32755613/

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Find here more information/studies about astaxanthin consumption and cholestrerol.

Objectives:
Dyslipidemia is a common metabolic disease worldwide and also an important predisposing factor for cardiovascular diseases (CVDs). Coffee is loved by people all over the world; however, the association between coffee consumption and blood lipids has yielded inconsistent results. Therefore, this review article has been conducted.

Is there a causal relationship between coffee consumption and dyslipidemia?

Study design:
This review article included 12 RCTs.

Results and conclusions:
The investigators found pooled results showed that coffee consumption significantly increased total cholesterol (TC) levels [WMD = 0.21 mmol/L, 95% CI = 0.04 to 0.39, p = 0.017].  
Significant means that there is an association with a 95% confidence.

The investigators found pooled results showed that coffee consumption significantly increased triglyceride (TG) levels [WMD = 0.12 mmol/L, 95% CI = 0.03 to 0.20, p = 0.006].  
Significant because the calculated p-value of 0.006 was less than the p-value of 0.05.

The investigators found pooled results showed that coffee consumption significantly increased LDL cholesterol (bad cholesterol) levels [WMD = 0.14 mmol/L, 95% CI = 0.05 to 0.24, p = 0.003].  

The investigators found pooled results showed that coffee consumption had no significant effect on HDL cholesterol (good cholesterol) levels [WMD = -0.01 mmol/L, 95% CI = -0.06 to 0.04, p = 0.707].
No significant means that there is no association with a 95% confidence.

The investigators found dose-response analysis results revealed significant positive nonlinear associations between coffee consumption and the increase in total cholesterol, LDL cholesterol and triglyceride levels.

The investigators concluded that coffee consumption is associated with an elevated risk for dyslipidemia and cardiovascular diseases. So a reasonable habit of coffee consumption (3 cups/d) is essential for the prevention of dyslipidemia.  

Original title:
Effect of coffee consumption on dyslipidemia: A meta-analysis of randomized controlled trials by Du Y, Lv Y, […], Luo Q.

Link:
https://pubmed.ncbi.nlm.nih.gov/33239163/

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Dyslipidemia is elevation of plasma cholesterol, triglycerides (TGs), or both, or a low HDL cholesterol (good cholesterol) level that contributes to the development of atherosclerosis. Atherosclerosis is the main underlying cause of cardiovascular disease (CVD).

Objectives:
A dietary protein intake (DPI) of between 0.6 and 0.8 g protein per kilogram body weight per day (g/kg/day) is frequently recommended for adults with moderate-to-advanced chronic kidney disease (CKD). However, evidence on whether patients with diabetic kidney disease (DKD) actually benefit from a DPI of ≤ 0.8 g/kg/day and from a low-protein diet (LPD) at CKD stages 1-3 has not been consistent. Therefore, this review article has been conducted.

Do patients with diabetic kidney disease benefit from a dietary protein intake of 0.8 g protein per kilogram body weight per day (g/kg/day)?

Study design:
This review article included 9 RCTs with a total of 506 participants and follow-up periods varying from 4.5 to 60 months.

Results and conclusions:
The investigators found that patients with diabetic kidney disease who consumed 0.8 g protein/kg/day had a significantly reduced decline in glomerular filtration rate (GFR) [MD = 22.31 mL/min/1.73 m², 95% CI = 17.19 to 27.42, p 0.01] and a significant decrease in proteinuria [SMD = -2.26 units, 95% CI = -2.99 to -1.52, p 0.001] versus those on the control diet.

The investigators found the benefits of a low-protein diet to patients with diabetic kidney disease at chronic kidney disease stages 1-3 were a markedly decreased proteinuria [SMD - 0.96 units, 95% CI = -1.81 to -0.11, p = 0.03] and slight but significant decreases in glycated hemoglobin [-0.42%] and cholesterol levels [-0.22 mmol/L].

The investigators concluded that a dietary protein intake of 0.8 g/kg/day is strongly associated with a slow decline in glomerular filtration rate (GFR) and decreases proteinuria in the patients with diabetic kidney disease. Patients with chronic kidney disease (CKD) stages chronic kidney disease 1-3 benefit from a low-protein diet in terms of a marked decrease of proteinuria and slight but significant improvements in lipid and glucose control.  

Original title:
Diabetic Kidney Disease Benefits from Intensive Low-Protein Diet: Updated Systematic Review and Meta-analysis by Li Q, Wen F, [...], Wang W.

Link:
https://pubmed.ncbi.nlm.nih.gov/33150563/

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For example: you are a patient with diabetic kidney disease, you weigh 70 kg and you want to eat 2200 kcal every day. How should you meet a dietary protein intake of 0.8 g protein per kilogram body weight per day (g/kg/day) in daily life?
Every day you should take maximal 0.8 g protein x 70 kg = 56 g protein. 56 g protein give 56x4 kcal = 224 kcal. 224 kcal is around 10% of 2200 kcal. Thus, you should eat products whose protein content contributes maximum 10% to the total kcal of the product in question, meaning you should eat products with 10 En% protein. These products in the supermarket contain maximum 10 En% protein.

Thus, a dietary protein intake of 0.8 g protein per kilogram body weight per day (g/kg/day) for a person weighing 70 kg on a diet of 2200 kcal, means he/she should eat products with maximum 10 En% protein in daily life.
 

Objectives:
Dietary sodium intake has received considerable attention as a potential risk factor of cardiovascular disease. However, evidence on the dose-response association between dietary sodium intake and cardiovascular disease risk is unclear. Therefore, this review article has been conducted.

Is there a dose-response association between dietary sodium intake and cardiovascular disease (CVD) risk?

Study design:
This review article included 36 cohort studies with a total of 616,905 participants.
The duration of follow-up ranged from 2.7 years to 29 years.

For dietary sodium intake assessment, 18 of the studies were based on twenty-four urinary excretion, 7 used food frequency questionnaires, 8 used 24 h dietary recall, 2 used dietary records; 1 used a self-administered questionnaire and 1 used single spot urine sodium excretion.
The daily dietary sodium intake ranged from 1.0 to 7.5 g.

The mean score (± standard deviation) for the quality of the included studies was 8.0 ± 1.0 according to the Newcastle-Ottawa Scale.

Results and conclusions:
The investigators found compared with individuals with low sodium intake, individuals with high sodium intake had an 19%-higher adjusted risk of cardiovascular disease [rate ratio = 1.19, 95% CI = 1.08 to 1.30].

The investigators found in dose-response meta-analysis that the risk of cardiovascular disease significantly increased by 6% when 1 g dose of sodium was ingested [rate ratio = 1.06, 95% CI = 1.01 to 1.11].

The investigators concluded that high sodium intake is an important risk factor of cardiovascular disease (CVD) and in dose-response meta-analysis, every 1 g of dietary sodium intake increases the risk of cardiovascular disease by 6%.

Original title:
Dietary Sodium Intake and Risk of Cardiovascular Disease: A Systematic Review and Dose-Response Meta-Analysis by Wang YJ, Yeh TL, [...], Chien KL.

Link:
https://www.mdpi.com/2072-6643/12/10/2934/htm

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1 gram salt (sodium chloride) = 0.4 gram sodium.

Objectives:
Soy products contain several compounds with anti-inflammatory properties like genistein and daidzein which reported to act through different pathways. However, there are inconsistent results and lack of any comprehensive review regarding randomized controlled trials which assess the effect of soy products on inflammatory markers. Therefore, this review article has been conducted.

Does soy product supplementation reduce levels of inflammatory markers, like CRP, IL-6?

Study design:
This review article included 51 RCTs.

Results and conclusions:
The investigators found soy product supplementation significantly reduced CRP levels [MD = -0.27 mg/L, 95% CI = -0.51 to -0.02, p = 0.028] but it did not affect IL-6 [MD = 0.0 pg/mL, 95% CI = -0.06 to 0.06, p = 0.970] and TNF-α [MD = -0.04 pg/mL, 95% CI = -0.11 to 0.03, p = 0.252].

The investigators found subgroup analysis showed that soy supplementation had a significant impact on decreasing IL-6 and TNF-α levels when studies had a long-term intervention (≥12 weeks) and used low dose isoflavone (100 mg/day).

The investigators concluded there is a significant reduction in CRP levels after soy product supplementation.

Original title:
The effects of soy supplementation on inflammatory biomarkers: A systematic review and meta-analysis of randomized controlled trials by Asbaghi O, Yaghubi E, […], Ghaedi E.

Link:
https://pubmed.ncbi.nlm.nih.gov/32979840/

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Find here more information/studies about soy consumption and chronic disease.

Objectives:
There is some inconclusive evidence for the role of fish consumption in susceptibility to multiple sclerosis (MS). Therefore, this review article has been conducted.

Does fish consumption reduce multiple sclerosis (MS)?

Study design:
This review article included 6 observational studies.

Results and conclusions:
The investigators found that the consumption of fish (at least 0.5 servings of fish per week) significantly decreased the risk of multiple sclerosis with 23% [OR = 0.77, 95% CI = 0.64 to 0.92, p-value = 0.004, I2 = 54.7%] compared with controls.

The investigators concluded that dietary intake of at least 0.5 servings of fish per week during adolescence and after reduce the risk of multiple sclerosis; however, further studies are required to prove this preventive effect.

Original title:
Dietary fish intake and the risk of multiple sclerosis: a systematic review and meta-analysis of observational studies by Rezaeizadeh H, Mohammadpour Z, […], Homayon IA.

Link:
https://pubmed.ncbi.nlm.nih.gov/32787642/

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Objectives:
Epidemiological studies on the impact of fish consumption on coronary heart disease (CHD) incidence have shown inconsistent results. Therefore, this review article has been conducted.

Does dietary intake of fish reduce coronary heart disease incidence and mortality?

Study design:
This review article included 40 prospective cohort studies (22 studies investigated the association between fish consumption and coronary heart disease incidence (28,261 persons with coronary heart disease and 918,783 participants) and 27 studies investigated the association between fish consumption and coronary heart disease mortality (10,568 events and 1,139,553 participants)).

No evidence of publication bias was found.

Results and conclusions:
The investigators found higher fish consumption was significantly associated with a 9%-lower coronary heart disease risk [RR = 0.91, 95% CI = 0.84 to 0.97, I2 = 47.4%].

The investigators found a significant correlation between fish consumption and coronary heart disease risk in the female subgroup [RR = 0.85, 95% CI = 0.78 to 0.92, I2 = 5.6%], the subgroup with a follow-up period of ≥10 years [RR = 0.91, 95% CI = 0.84 to 0.99, I2 = 51.5%] and the subgroup with an article quality of ≥7 points [RR = 0.90, 95% CI = 0.83 to 0.98, I2 = 50.6%].
However, it was not found in the male subgroup, the subgroup with a follow-up period of 10 years and the subgroup with an article quality of 7 points.

The investigators found higher fish intake was significantly associated with a 15%-lower coronary heart disease mortality risk [RR = 0.85, 95% CI = 0.77 to 0.94, I2 = 51.3%].

The investigators found the summary results did not change significantly in sensitivity analysis.

The investigators found dose-response analysis showed that the coronary heart disease incidence and mortality were reduced by 4%, respectively, with a 20 g/day increment in fish consumption.

The investigators concluded that a higher dietary intake of fish reduces coronary heart disease incidence and mortality. This finding has important public health implications in terms of the prevention of coronary heart disease. Since most of the research was conducted in male groups and Western countries, further research needs to be performed in female groups and other regions.

Original title:
Fish Consumption and Coronary Heart Disease: A Meta-Analysis by Zhang B, Xiong K, […], Ma A.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7468748

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In practice, higher fish consumption means at least twice a week of fish consumption (150 grams of fish at a time).

Objectives:
Observational studies regarding the putative associations between dietary intake of homocysteine metabolism-related B-vitamins (vitamin B6, folate and vitamin B12) and stroke risk have yielded inconsistent results. Therefore, this review article has been conducted.

Does dietary intake of vitamin B6, folate or vitamin B12 reduce stroke risk?

Study design:
This review article included 1 nested case-control study and 11 prospective cohort studies comprising 389,938 participants and 10,749 cases (persons with stroke).

The studies were published from 2002 through to 2019 and the follow-up period ranged from 4.2 to 19 years.

All 12 studies provided risk estimates adjusted for cigarette smoking and most studies also adjusted for other conventional risk factors, including BMI, energy intake, alcohol consumption, hypertension and/or physical activity.

Study quality scores ranged from 5 to 9; the mean quality score was 7.4.

There was no evidence of publication bias.

Results and conclusions:
The investigators found for the highest versus the lowest category of dietary vitamin B6 intake, a significantly reduced risk of 16% for stroke [RR = 0.84, 95% CI = 0.73 to 0.97, I2 = 48.8%].

The investigators found in dose-response analysis that each 0.5 mg/d increment in vitamin B6 dietary intake was associated with a 6% reduction in the risk of stroke [RR = 0.94, 95% CI = 0.89 to 0.99, I2 = 77.0%].

The investigators found for the highest versus the lowest category of dietary folate intake, a significantly reduced risk of 15% for stroke [RR = 0.85, 95% CI = 0.78 to 0.94, I2 = 11.5%].

The investigators found in dose-response analysis that each 100 μg/d increase in dietary folate intake was associated with a 6% reduction in the risk of stroke [RR = 0.94, 95% CI = 0.90 to 0.98, I2 = 46.8%].

The investigators found, in contrast, no significant association between dietary vitamin B12 intake and the risk of stroke, with an RR of 1.01 [95% CI = 0.97 to 1.06] per 3 μg/d increase.

The investigators concluded increased dietary intake of vitamin B6 (at least 0.5 mg/d) and dietary folate intake (at least 100 μg/d) is associated with a reduced risk of stroke, supporting the notion that increasing habitual folate and vitamin B6 intake may provide a small but beneficial effect with respect to stroke.

Original title:
Dietary Intake of Homocysteine Metabolism-Related B-Vitamins and the Risk of Stroke: A Dose-Response Meta-Analysis of Prospective Studies by Chen L, Li Q, [...], Wang F.

Link:
https://academic.oup.com/advances/advance-article/doi/10.1093/advances/nmaa061/5854025

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Objectives:
Hypertension is regarded as a major and independent risk factor of cardiovascular diseases and numerous studies observed an inverse correlation between vitamin C intake and blood pressure. Therefore, this review article has been conducted.

Does a high serum vitamin C reduce blood pressure?

Study design:
This review article included 11 cross-sectional studies and 7 case-control studies. These studies comprised 22,200 observational subjects and were conducted from the year 1990 to 2017. Of the 18 articles, 14 were published in the English language and 4 were in Chinese.

Assessed with NOS, all the case-control studies yield a high quality averaging with 7.143 scores. And the result of AHRQ indicates a moderate quality with all cross-sectional studies scoring between 4 and 7.

Results and conclusions:
The investigators found random-effects model showed serum level of vitamin C of hypertensive subjects was 15.13 μmol/L lower than the normotensives [MD = -15.13, 95% CI = -24.19 to -6.06, p = 0.001, I2 = 98%].

The investigators found subgroup analysis showed that hypertensive subjects who took antihypertensive drugs had a 15.97 μmol/L lower serum vitamin C compared with normotensive ones.

The investigators found serum vitamin C had a significant inverse relation with both systolic blood pressure [Fisher′s Z = -0.17, 95% CI = -0.20 to -0.15, p 0.00001] and diastolic blood pressure [Fisher′s Z = -0.15, 95% CI = -0.20 to -0.10, p 0.00001].

The investigators concluded people with hypertension have a relatively low serum vitamin C and vitamin C is inversely associated with both systolic blood pressure and diastolic blood pressure.

Original title:
Association between Serum Vitamin C and the Blood Pressure: A Systematic Review and Meta-Analysis of Observational Studies by Ran L, Zhao W, […], Bu H.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211237/

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Objectives:
The relationship between dietary pattern and the risk of chronic obstructive pulmonary disease (COPD) has been described; however, the exclusive role of dietary factors remains controversial. Therefore, this review article has been conducted.

Does a dietary intake of fruits and vegetables, dietary fiber, fish, n-3 or n-6 fatty acids and antioxidant vitamins reduce risk of COPD in adults?

Study design:
This review article included 10 cohort, 6 case-control and 20 cross-sectional studies.

To assess usual dietary intake, 28 studies had used food frequency questionnaires (FFQ), of which 2 studies had used FFQ and a 24-hour recall, 3 studies had used the crosscheck dietary method, 1 study had assessed with only 24-hour recall and 1 study had used weighted household food records.

Results and conclusions:
The investigators found a significantly reduced risk of 26% [relative risk = 0.74, 95% CI = 0.65 to 0.85] for COPD for the highest fruit intake group compared with the lowest intake group.
This significantly reduced risk was 29% in cohort studies [RR = 0.71, 95% CI = 0.63 to 0.79, I2 = 0.0%].

The investigators found a significantly reduced risk of 47% [relative risk = 0.53, 95% CI = 0.39 to 0.74, I2 = 0.0%, p = 0.65] for COPD mortality for the highest fruit intake group compared with the lowest intake group.

The investigators found a significantly reduced risk of 35% [relative risk = 0.65, 95% CI = 0.55 to 0.78] for COPD for the highest dietary fiber intake group compared with the lowest intake group.
This significantly reduced risk was 39% in cohort studies [RR = 0.61, 95% CI = 0.54 to 0.68, I2 = 0.0%, p = 0.9].

The investigators found a significantly reduced risk of 29% [relative risk = 0.71, 95% CI = 0.58 to 0.85] for COPD for the highest fish intake group compared with the lowest intake group.

The investigators found a significantly reduced risk of 11% [relative risk = 0.89, 95% CI = 0.76 to 0.99] for COPD for the highest vitamin C dietary intake group compared with the lowest intake group.

The investigators found no association between the risk of COPD and the intake of vegetables, n-3 fatty acids, vitamin E and β-carotene.

The investigators concluded that a higher dietary intake of fruit, dietary fiber, fish and vitamine C reduce the risk of COPD in adults.

Original title:
Dietary Factors and Risk of Chronic Obstructive Pulmonary Disease: A Systemic Review and Meta-Analysis by Seyedrezazadeh E, Moghaddam MP, […], Kolahdooz F.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7309892/

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Objectives:
Is there a causal relationship between black or green tea consumption and lowering blood pressure in subjects with elevated blood pressure (BP) or hypertension?
 
Study design:
This review article included 5 RCTs with 408 individuals.

None of the studies reported any side effects.

Results and conclusions:
The investigators found regular tea consumption significantly reduced systolic blood pressure [WMD = -4.81 mmHg, 95% CI = -8.40 to -1.58, p = 0.004] in subjects with elevated blood pressure (BP) or hypertension.

The investigators found regular tea consumption significantly reduced diastolic blood pressure [WMD = -1.98 mmHg, 95% CI = -3.77 to -0.20, p = 0.029] in subjects with elevated blood pressure (BP) or hypertension.

The investigators found, however, excluding the most heterogeneous trials showed that regular tea intake significantly reduced systolic blood pressure and diastolic blood pressure by about -3.53 and -0.99 mmHg, respectively.

The investigators found based on meta-regression findings, the longer the duration of tea intake (≥3 months), the higher the decrease in both systolic blood pressure and diastolic blood pressure.

The investigators found categorized studies, according to the tea type, revealed that the hypotensive effects of green tea were more pronounced compared to black tea.

The investigators concluded regular tea consumption, particularly green tea during ≥3 months reduces systolic blood pressure and diastolic blood pressure in subjects with elevated blood pressure (BP) or hypertension. Hence, it may be applicable to physicians, health care providers and particularly hypertension patients.

Original title:
The Effects of Regular Consumption of Green or Black Tea Beverage on Blood Pressure in Those With Elevated Blood Pressure or Hypertension: A Systematic Review and Meta-Analysis by Mahdavi-Roshan M, Salari A, […], Ashouri A.

Link:
https://www.sciencedirect.com/science/article/abs/pii/S0965229919316899?via%3Dihub

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Objectives:
Epidemiologic studies, including trials, suggest an association between potassium intake and blood pressure (BP). However, the strength and shape of this relationship is uncertain. Therefore, this review article has been conducted.

What is the strength and shape of the relationship between potassium intake and blood pressure (BP)?
 
Study design:
This review article included 32 RCTs with a duration ≥4 weeks using the recently developed 1‐stage cubic spline regression model. This model allows use of trials with at least 2 exposure categories.
Most trials were conducted in adults with hypertension using a crossover design and potassium supplementation doses that ranged from 30 to 140 mmol (1173 and 5474 mg) per day.

Results and conclusions:
The investigators found a U‐shaped relationship between 24‐hour active and control arm differences in potassium excretion and blood pressure (BP) levels, with weakening of the blood pressure reduction effect above differences of 30 mmol/d and a blood pressure increase above differences ≈80 mmol/d.

The investigators found achieved potassium excretion analysis also identified a U‐shaped relationship. The blood pressure lowering effects of potassium supplementation were stronger in participants with hypertension and at higher levels of sodium intake.

The investigators found blood pressure increased with high potassium excretion in participants with antihypertensive drug‐treated hypertension but not in their untreated counterparts.

The investigators concluded that an adequate intake of potassium (≤30 mmol (1173 mg) per day) is desirable to achieve a lower blood pressure level but excessive potassium supplementation (>80 mmol (3128 mg) per day) should be avoided, particularly in specific subgroups.

Original title:
Potassium Intake and Blood Pressure: A Dose‐Response Meta‐Analysis of Randomized Controlled Trials by Filippini T, Naska A, […], Whelton PK.

Link:
https://www.ahajournals.org/doi/full/10.1161/JAHA.119.015719?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed&

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Objectives:
Vitamin D deficiency has been related to the risk of sepsis. However, previous studies showed inconsistent results regarding the association between serum 25-hydroxyvitamin D (25 (OH)D) and mortality risk in septic patients. Therefore, this review article has been conducted.

Does a low serum 25-hydroxyvitamin D (vitamin D level in blood) increase mortality risk in septic patients?

Study design:
This review article included 8 follow-up studies (4 were prospective and the other 4 were retrospective) with 1,736 septic patients.

The sample sizes of the included studies varied from 57 to 610.
The mean ages of the patients included in each study ranged from 57 to 75 years and the proportions of male patients varied from 43% to 71%.

Optimal vitamin D level, vitamin D insufficiency, vitamin D deficiency and severe vitamin D deficiency are defined as serum 25 (OH)D > 30 ng/mL, 21-29 ng/mL and  20 ng/mL, 10 ng/mL, respectively.

There was no publication bias.

Results and conclusions:
The investigators found meta-analysis with a random-effect model showed that septic patients with lower serum 25 (OH)D ( 30 ng/ml) at admission was associated with a significantly increased mortality risk of 93% [adjusted RR = 1.93, 95% CI = 1.41 to 2.63, p  0.001, I2 = 63%, p = 0.003].
Sensitivity analysis by excluding one study at a time did not significantly change the results.

The investigators found subgroup analyses according to the severity of vitamin D deficiency showed that patients with severe vitamin D deficiency ( 10 ng/mL) was significantly associated with a 92% higher mortality risk [adjusted RR = 1.92, 95% CI = 1.09 to 2.55, p  0.001].
But the associations were not significant for vitamin D insufficiency (25 (OH)D = 20-30 ng/mL) or deficiency (25 (OH)D = 10-20 ng/mL).

The investigators found further analyses showed that the association between lower serum 25(OH) D and higher mortality risk were consistent in studies applied different diagnostic criteria for sepsis (SIRS, Sepsis-2.0 or Sepsis-3.0), short-term (within 1 month) and long-term studies (3-12 months) and in prospective and retrospective studies.

The investigators concluded that severe vitamin D deficiency ( 10 ng/mL) is independently associated with increased mortality in patients with sepsis. Large-scale prospective studies are needed to validate these findings.

Original title:
Serum 25-Hydroxyvitamin D and the risk of mortality in adult patients with Sepsis: a meta-analysis by Li Y and Ding S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7057612/

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Objectives:
Is there a causal relationship between tomato consumption and lowering effects on cholesterol, triglycerides or fasting blood sugar levels?
 
Study design:
This review article included 6 RCTs.

Results and conclusions:
The investigators found tomato consumption significantly reduced total plasma cholesterol levels [WMD = -4.39 mg/dL, 95% CI = -7.09 to -1.68, I2 = 48%, p = 0.05].

The investigators found tomato consumption significantly reduced plasma triglyceride (TG) levels [WMD = -3.94 mg/dL, 95% CI = -7.67 to -0.21, I2 = 90%, p = 0.001].
A higher reduction effect was found on younger participants.

The investigators found tomato consumption significantly reduced plasma LDL cholesterol (bad cholesterol) levels [WMD = -2.09 mg/dL, 95% CI = -3.73 to -0.81, I2 = 78%, p = 0.001].
A higher reduction effect was found on younger participants.

The investigators found tomato consumption significantly increased plasma HDL cholesterol (good cholesterol) levels [WMD = 2.25 mg/dL, 95% CI = 0.41 to 4.10, I2 = 97%, p = 0.001].

The investigators found tomato consumption had no significant effect on plasma fasting blood sugar levels [WMD = 0.59 mg/dL, 95% CI = -0.28 to 1.46, I2 = 95%, p = 0.001].

The investigators concluded that tomato consumption increases plasma HDL cholesterol (good cholesterol) levels and decreases plasma total cholesterol, LDL cholesterol (bad cholesterol) and triglyceride levels.

Original title:
Effect of Tomato Consumption on Fasting Blood Glucose and Lipid Profiles: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Li H, Chen, A, [...],Yin X.

Link:
https://pubmed.ncbi.nlm.nih.gov/32243013/

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Patients with heart disease often have high LDL cholesterol, low HDL cholesterol and high triglycerides levels.

Objectives:
Do dietary calcium intakes or calcium supplements increase risk of cardiovascular disease?
 
Study design:
This review article included 26 prospective cohort studies and 16 RCTs.

Results and conclusions:
The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of cardiovascular disease [relative risk = 0.96, 95% CI = 0.87 to 1.05].

The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of coronary heart disease [relative risk = 0.98, 95% CI = 0.88 to 1.08].

The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of stroke [relative risk = 0.94, 95% CI = 0.85 to 1.04].

The investigators found in RCTs that calcium supplements significantly increased risk of coronary heart disease with 20% [relative risk = 1.20, 95% CI = 1.08 to 1.33, I2 = 0.0%].

The investigators found in RCTs that calcium supplements significantly increased risk of myocardial infarction with 21% [relative risk = 1.21, 95% CI = 1.08 to 1.35, I2 = 0.0%].

The investigators concluded that 200-1500 mg/d calcium intake from dietary sources do not increase the risk of cardiovascular disease, including coronary heart disease and stroke, while calcium supplements increase coronary heart disease risk, especially myocardial infarction.

Original title:
The Evidence and Controversy Between Dietary Calcium Intake and Calcium Supplementation and the Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Cohort Studies and Randomized Controlled Trials by Yang C, Shi X, […], Sun G.

Link:
https://pubmed.ncbi.nlm.nih.gov/31625814/

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Objectives:
Multiple sclerosis (MS) is a demyelinating and disabling inflammatory disease of the central nervous system. Multiple sclerosis is triggered by complex environmental factors which mostly affect genetically the susceptible young people. Emerging data has suggested that changes of homocysteine (Hcy), vitamin B12 and folate serum levels may be associated with multiple sclerosis. However, previous findings are not always consistent. Therefore, this review aricle has been conducted.

Does a low serum homocysteine, vitamin B12 or folate level increase risk of multiple sclerosis?

Study design:
This review article included 21 original studies with 1,738 multiple sclerosis patients and 1,424 controls (patients without multiple sclerosis). There were 17 studies for measuring homocysteine, 16 studies for measuring vitamin B12 and 13 studies for measuring folate in patients with multiple sclerosis, respectively.

Results and conclusions:
The investigators found patients with multiple sclerosis (MS) had higher serum levels of homocysteine [SMD = 0.64, 95% CI = 0.33 to 0.95, p 0.0001] compared with control groups.

The investigators found no significant differences of SMD for vitamin B12 [SMD = -0.08, 95% CI = -0.35 to 0.20, p = 0.58] or folate [SMD = 0.07, 95% CI = -0.14 to 0.28, p = 0.52] between MS and controls.

The investigators found subgroup analysis demonstrated that there was statistically significant difference for homocysteine between relapsing-remitting MS (RRMS) patients and controls with a SMD of 0.67 [95% CI = 0.21 to 1.13, p = 0.004].

However, no significant difference of homocysteine serum levels between secondary progressive MS patients or primary progressive MS patients and controls.

The investigators found no significant difference of homocysteine levels in females [SMD = 0.22, 95% CI = -0.16 to 0.60, p = 0.25] or males [SMD = 0.56, 95% CI = -0.13 to 1.26, p = 0.11] between MS patients and controls.

The investigators concluded higher serum levels of homocysteine increase risk of multiple sclerosis (MS), especially for relapsing-remitting MS (RRMS) patients. Functional studies are required to assess the effects of homocysteine on patients with MS at the molecular level.

Original title:
Serum levels of Homocysteine, Vitamin B12 and Folate in Patients with Multiple Sclerosis: an Updated Meta-Analysis by Li X, Yuan J, [...], Hu W.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7085269/

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Objectives:
Is there a causal relationship between daily egg consumption and positive effects on blood pressure?
 
Study design:
This review article included 15 RCTs with a total of 748 participants and mean age range from 23.3 to 67.1 years old.

All included studies used whole egg as an intervention which varied from one egg/day to three eggs/day and duration of supplementation ranged from 3 to 12 weeks.

No evidence of publication bias was seen in the meta-analyse (review article) of systolic blood pressure [Begg’s p = 0.235, Eggers’s p = 0.433] and diastolic blood pressure [Begg’s p = 0.254, Eggers’s p = 0.267].

No heterogeneity was found among included studies.

Results and conclusions:
The investigators found, overall, egg consumption had no significant effect on systolic blood pressure [WMD = 0.046 mmHg, 95% CI = - 0.792 to 0.884, p = 0.914, I2 = 0.0%, p = 0.453] and diastolic blood pressure [WMD = -0.603 mmHg, 95% CI = -1.521 to 0.315, p = 0.198, I2 = 38.1%, p = 0.067].
Subgroup analyses had no effect on pooled results.
Sensitivity analysis indicated that excluding each trial did not significantly change the overall observed effects of egg consumption.

The investigators found nonlinear dose-response meta-analysis did not reveal a significant effect of egg consumption [p-nonlinearity = 0.76] and study duration on diastolic blood pressure [p-nonlinearity = 0.63].

The investigators found subgroup analyses based on study design, sex, population health status, obesity and hypertension status, diet adherence, study duration and amount of egg consumption did not affect the overall effects of egg consumption on systolic blood pressure and diastolic blood pressure values.

The investigators concluded that 1-3 eggs/day during 3 to 12 weeks have no effect on blood pressure. However, high-quality RCTs with longer durations are needed to further confirm the effects of egg consumption on blood pressure.

Original title:
Effect of Egg Consumption on Blood Pressure: a Systematic Review and Meta-analysis of Randomized Clinical Trials by Kolahdouz-Mohammadi R, Malekahmadi M, […], Soltani S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7189334/

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Objectives:
Physical exercise may offer multiple benefits to patients with chronic kidney disease (CKD). However, it was not traditionally recommended because of the possibility of impairing renal function and increasing proteinuria. Therefore, this review aricle has been conducted.

Does low-intensity physical exercise offer benefits to patients with chronic kidney disease?

Study design:
This review article included 21 RCTs with a intervention of at least 12 weeks and 927 patients.

The frequency of low-intensity physical exercise in 14 studies was 3 times per week during 30 minutes.

Results and conclusions:
The investigators found no differences in glomerular filtration rate or proteinuria between the intervention group (group with low-intensity physical exercise) and the control group (group without low-intensity physical exercise) [SMD = -0.3, p = 0.81 and SMD = 26.6, p = 0.82].

The investigators found positive effects on peak oxygen consumption [SMD = 2.5, p 0.001], functional capacity [SMD = 56.6, p 0.001], upper limb strength [SMD = 6.8, p 0.001] and haemoglobin [SMD = 0.3, p = 0.003] for the intervention group.

The investigators found an improvement on the quality of life, using the KDQOL-36 survey [SMD = 3.56, p = 0.02] and the SF-36 survey [SMD = 6.66, p = 0.02] for the intervention group.

The investigators concluded low-intensity physical exercise routinely has no negative impact on renal function. On the contrary, it improves aerobic and functional capacity, impacting positively on the quality of life.

Original title:
Impact of physical exercise in patients with chronic kidney disease: Sistematic review and meta-analysis by Villanego F, Naranjo J, […], Mazuecos A.

Link:
https://reader.elsevier.com/reader/sd/pii/S0211699520300266?token=62CEB2BCF50CE23B396565B5DC989F795AEEB75C666C74AA410FD2172DB39F90DBBB5D72BF3B4347C0C8AD2FEF8B0110

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Low-intensity physical exercises are a casual walk, a stretch session, a beginners' yoga class or tai chi.

Objectives:
Does Alzheimer disease increase risk of stroke?

Study design:
This review article included 8 studies, representing 121,719 individuals (Alzheimer disease = 73,044 and non-Alzheimer disease = 48,675).

Results and conclusions:
The investigators found patients with Alzheimer disease had a significantly increased risk of 42% [relative risk = 1.42, 95% CI = 1.23 to 1.64] for hemorrhagic stroke.

The investigators concluded Alzheimer disease increases risk of hemorrhagic stroke.

Original title:
Risk of hemorrhagic and ischemic stroke in patients with Alzheimer disease: A synthesis of the literature by Waziry R, Chibnik LB, […], Hofman A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31949087

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