Nutritional advice

Objectives:
The aim of this review article is to evaluate evaluated the association of place of residence (urban/rural) and under-five mortality in middle- and low-income countries.

Study design:
This review article included 15 studies.

Results and conclusions:
The investigators found that when the results from all studies were combined, the RR of under-five mortality was higher for those living in rural areas. The overall combined effect size was determined to be 1.47 [95% CI = 1.27-1.67].

The investigators found meta-regression showed that there was a positive relationship between the percentage of rural population for the various countries/regions and the relative risk for under-five mortality by place of residence. The beta coefficient (β) for the rural population percentage was 0.007, meaning that for every one percent increase in the rural population, there was a 0.007 increase in risk of under-five mortality. This, however, was not significant [95% = -0.006 to 0.02, p-value = 0.3].

The investigators found sensitivity analysis indicated that rural disadvantage held true even when successive studies were omitted and the combined RR was greater than 1. This provided evidence as to the robustness of the results.

The investigators concluded under-five mortality risk is higher for rural areas than urban areas in middle- and low-income countries. This finding is important to evaluate policies and programmes designed to remove the gap in under-five mortality rates between urban and rural areas.

Original title:
Association of Place of Residence and Under-Five Mortality in Middle- and Low-Income Countries: A Meta-Analysis by Forde I and Tripathi V.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5920397/

Additional information of El Mondo:
Find more information/studies on food fortification/malnutrition and study design/meta-analysis/significant right here.

Objectives:
N-3 polyunsaturated fatty acids (PUFA) have been postulated to have an anti-arrhythmic effect on postoperative atrial fibrillation (POAF), with conflicting results among studies. Therefore, this review article has been conducted.

Do n-3 polyunsaturated fatty acids reduce risk of postoperative atrial fibrillation among patients undergoing cardiac surgery?

Study design:
This review article included 4 studies with 3,570 patients.
The funnel plot and fail-safe number suggested insignificant publication bias.

Results and conclusions:
The investigators found n-3 polyunsaturated fatty acids significantly reduced risk of postoperative atrial fibrillation with 16% [RR = 0.84, 95% CI = 0.73-0.98, p = 0.03].
Significantly means it can be said with a 95% confidence that n-3 polyunsaturated fatty acids really reduced the risk of postoperative atrial fibrillation with 16%. 

The investigators found in subgroup analyses EPA:DHA 1 significantly reduced risk of postoperative atrial fibrillation with 49% [RR = 0.51, 95% CI = 0.36-0.73, p = 0.0003].

The investigators found in subgroup analyses, when placebo was usual care, n-3 polyunsaturated fatty acids significantly reduced risk of postoperative atrial fibrillation with 41% [RR = 0.59, 95% CI = 0.44-0.80, p = 0.0005].

The investigators found in subgroup analyses, n-3 polyunsaturated fatty acids significantly reduced risk of postoperative atrial fibrillation with 32% after coronary artery bypass grafting (CABG) [RR = 0.68, 95% CI = 0.47-0.97, p = 0.03].

The investigators concluded that n-3 polyunsaturated fatty acids (PUFA), particularly at EPA/DHA ratio of  1 reduce risk of postoperative atrial fibrillation after coronary artery bypass grafting (CABG). Further studies are needed to confirm the effect of PUFA on postoperative atrial fibrillation and to assess the proper use of PUFA against postoperative atrial fibrillation.

Original title:
N-3 polyunsaturated fatty acids for prevention of postoperative atrial fibrillation: updated meta-analysis and systematic review by Wang H, Chen J and Zhao L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29380237

Additional information of El Mondo:
Find more information/studies on review article/significantly, EPA&DHA, PUFA and cardiovascular disease right here.

Objectives:
There is an increasing trend in the consumption of poor-quality diets worldwide, contributing to the increase of non-communicable diseases. Diet directly influences physiological composition and subsequently physical health. Studies have shown that dietary macronutrient and energy content can influence the proportion of intramuscular fat (IMF), which mediates various metabolic and endocrine dysfunction. Therefore, this review article has been conducted.

Do different types of dietary macronutrient intake increase the proportion of intramuscular fat?

Study design:
This review article included 13 trials (RCTs, quasi-RCTs, controlled trials, randomized controlled crossover trials or controlled crossover trials).

High-fat diets were diets with a proportion of fat between 38 and 85 En%. Participants in high-fat diets were all young to middle aged adults with ages varying between 18 and 50 years.

Participants in starvation diets (a decrease of 25% calorie from weight maintenance energy requirements) and hypocaloric diets (890 calories per day, until 15% weight reduction) followed the diet for 8 days with a 3-week washout period in between.

Cohen’s criteria were used to determine the effect size of SMDs, where a SMD between 0.2 and 0.5 is small, a SMD between 0.5 and 0.8 is moderate and a SMD above 0.8 is large. SMDs below 0.2 were considered unsubstantial.

Results and conclusions:
The investigators found in 6 studies with in a total of 134 participants receiving a high-fat intervention and 135 people receiving a control intervention, that high-fat diets (38 and 85 En% fat) significantly increased the proportion of intramuscular fat [SMD = 1.24, 95% CI = 0.43-2.05, p  = 0.003, I2 = 87%].  
Sensitivity analysis (excluding studies with a quality value 20, smallest sample size 8 and those that do not specify participant characteristics) showed a significantly SMD of 1.26 [95% CI = 0.23-2.28, p = 0.02]. 

The investigators found diets with an increased proportion of carbohydrates decreased the proportion of intramuscular fat.
However, increasing caloric intake with carbohydrates compared to a standardized diet (55 En% carbohydrates, 30 En% fat and 15 En% protein) increased the proportion of intramuscular fat.

The investigators found starvation diets (a decrease of 25% calorie from weight maintenance energy requirements) increased intramuscular fat stores and hypocaloric diets (890 calories per day, until 15% weight reduction) did not result in any intramuscular fat proportion changes.

The investigators concluded that high-fat diets (38 y 85 En%), excessive caloric intake in the form of carbohydrates and short-term starvation diets are associated with increases in the proportion of intramuscular fat. However, further studies are needed to assess the effects of macronutrient combinations on intramuscular fat and the influence of diet-induced intramuscular fat alterations on health outcomes. In addition, intramuscular fat poses a possibly effective clinical marker of health.

Original title:
The Effects of Diet on the Proportion of Intramuscular Fat in Human Muscle: A Systematic Review and Meta-analysis by Ahmed S, Singh D, [...], Kumbhare D.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5826234/

Additional information of El Mondo:
Find more information/studies on fat and carbohydrates consumption and diabetes right here.

Higher intramuscular fat levels are positively associated with insulin resistance and an increased risk of developing type 2 diabetes.

Objectives:
Esophageal cancer (EC) is the eighth most common cancer and the sixth most frequent cause of cancer death in the whole world. Many studies have investigated the association between citrus fruit intake and the risk of esophageal cancer, but the results are inconsistent and not analyzed by category. Therefore, this review article has been conducted.

Does citrus fruit intake reduce esophageal cancer risk?

Study design:
This review article included 20 case-control studies and 5 cohort studies.
The studies were published between 1983 and 2015 with a total of 2,456 esophageal squamous cell carcinoma (ESCC) (range 47-395), 1,284 esophageal adenocarcinoma (EAC) (range 67-282) and 1,990 esophageal cancer (EC) (range 53-1,246).

The Newcastle-Ottawa Quality Assessment Scale (NOS) scores of 25 clinical trials range from 5 to 9, with an average of approximately 7. The median score was 6.75 for case-control studies and 8 for cohort studies.

There was no evidence of publication bias. 

Results and conclusions:
The investigators found in 10 case-control studies and 3 cohort studies a significantly reduced risk of 41% [pooled RR = 0.59, 95% CI = 0.47-0.76, I2 = 60.7%, p  = 0 .002] for esophageal squamous cell carcinoma in the citrus fruit consumption group.
Significant because RR of 1 was not found in the 95% CI of 0.47 to 0.76. RR of 1 means no risk/association.

The investigators found in 5 case-control studies and 3 cohort studies a non-significantly reduced risk of 14% [pooled RR = 0.86, 95% CI = 0.74-1.01, I2 = 0.0%, p = 0.598] for esophageal adenocarcinoma in the citrus fruit consumption group.
Non-significantly because RR of 1 was found in the 95% CI of 0.74 to 1.01. RR of 1 means no risk/association.

The investigators found in 20 case-control studies and 5 cohort studies a significantly reduced risk of 35% [pooled RR = 0.65, 95% CI = 0.56-0.75, I2 = 51.1%, p = 0.001] for esophageal cancer in the citrus fruit consumption group.

The investigators found in subgroup analysis significant inverse associations between citrus fruit intake and the risk of esophageal squamous cell carcinoma in cohort studies [OR  =  0.66, 95% CI = 0.49-0.88] and hospital-based cohort studies [OR  =  0.82, 95% CI = 0.33-0.75], but not in population-based cohort studies [OR  =  0.82, 95% CI = 0.62-1.09].

The investigators found in subgroup analysis significant inverse associations between citrus fruit intake and the risk of esophageal squamous cell carcinoma in >7 scores studies [OR =  0.56, 95% CI = 0.43-0.72].

The investigators concluded that citrus fruit intake reduces risk of esophageal cancer, particularly esophageal squamous cell carcinoma. However, further studies are warranted to find which constituents in citrus fruit prevent esophageal cancer and its mechanism.

Original title:
Intakes of citrus fruit and risk of esophageal cancer: A meta-analysis by Zhao W, Liu L and Xu S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5895383/

Additional information of El Mondo:
Find more information/studies on fruit consumption and cancer right here.

Objectives:
The relationship between vitamin intake and pancreatic cancer (PC) risk is disputed. Therefore, this review article has been conducted.

Is there a relationship between dietary vitamin intake and pancreatic cancer risk?

Study design:
This review article included 25 observational studies with a total of 1,214,995 individuals, of which 8,000 pancreatic cancer cases.

In the identified studies, 10 were population-based case-control studies, 4 were hospital-based case-control studies, 2 were RCTs, 9 were cohort studies, 11 were prospective studies and 14 were retrospective studies.
The number of participants ranged from 305 to 537,218 and pancreatic cancer cases ranged from 79 to 2,383.
Quality scores of included case-control and cohort studies ranged from 7 to 9 with an average score of about 8.

Results and conclusions:
The investigators found in prospective cohort studies a significantly reduced risk of 10% [multivariable-adjusted RR = 0.90, 95% CI = 0.83-0.98, I2 = 11%] for pancreatic cancer when comparing the highest dietary vitamin intake with the lowest, particularly for 10 μg/d dietary intake of vitamin D [multivariable-adjusted RR = 0.75, 95% BI = 0.60-0.93, I2  =  59%].

The investigators concluded that a high dietary vitamin intake decreases the risk of pancreatic cancer, particularly for 10 μg/d dietary intake of vitamin D.

Original title:
Vitamin intake and pancreatic cancer risk reduction: A meta-analysis of observational studies by Liu Y, Wang X, [...], Liu S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5895396/

Additional information of El Mondo:
Find more information/studies on vitamin D and cancer right here.

A review article (a collection of scientific studies on a specific topic) of cohort studies or case-control studies will answer the following question:
"Should I change my diet?".

Objectives:
The evidence is mixed on the use of long chain omega 3 fatty acids in the prevention and management of childhood asthma. Therefore, this meta-analysis (systematic review) has been conducted.

Does fish consumption reduce risk of childhood asthma?

Study design:
This review article included 23 observational studies on fish intake in association with childhood asthma.

Results and conclusions:
The investigators found in 15/23 studies early introduction of fish (6-9 months) and regular consumption (at least once a week) improved asthma symptoms and reduced risk in children 0-14 years as compared to no fish consumption; 6/23 showed no effect and 2/23 studies suggested adverse effects.

The investigators found a significantly reduced risk of 25% [OR = 0.75, 95% CI = 0.60-0.95] for all fish intake on current asthma in children up to 4.5 years old. 

The investigators found a significantly reduced risk of 38% [OR = 0.62, 95% CI = 0.48-0.80] for all fish intake on current wheeze in children up to 4.5 years old.

The investigators found as compared to no fish intake, a significantly reduced risk of 65% [OR = 0.35, 95% CI = 0.18-0.67] for fatty fish intake on asthma in children 8-14 years old. 

The investigators concluded that introduction of fish early in life (6-9 months) and regular consumption of all fish (at least once a week) reduces asthma and wheeze in children up to 4.5 years old, while fatty fish intake has beneficial effects in older children (8-14 years). Future well-designed clinical trials are recommended to confirm the promising findings documented in this literature analysis.

Original title:
The role of fish intake on asthma in children: A meta-analysis of observational studies by Papamichael MM, Shrestha SK, [...], Erbas B.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29524247

Additional information of El Mondo:
Find more information/studies on chronic diseases and fish consumption right here.

Objectives:
The efficacy of myo-inositol supplementation to prevent gestational diabetes onset remains controversial. Therefore, this meta-analysis (systematic review) has been conducted.

Does myo-inositol supplementation reduce risk of gestational diabetes in pregnant women?

Study design:
This review article included 5 RCTs.

Results and conclusions:
The investigators found compared with control group in pregnant women, myo-inositol supplementation significantly reduced risk of gestational diabetes with 57% [risk ratio = 0.43, 95% CI = 0.21-0.89, p = 0.02].

The investigators found compared with control group in pregnant women, myo-inositol supplementation significantly reduced risk of preterm delivery with 64% [risk ratio = 0.36, 95% CI = 0.17-0.73, p = 0.005].

The investigators found compared with control group in pregnant women, no association between myo-inositol supplementation and 2-h glucose oral glucose tolerance test (OGTT) [mean difference = -6.90, 95% CI = -15.07 to 1.27, p = 0.10].

The investigators found compared with control group in pregnant women, no association between myo-inositol supplementation and gestational age at birth [MD = 0.74, 95% CI = -1.06 to 2.54, p = 0.42].

The investigators found compared with control group in pregnant women, no association between myo-inositol supplementation and birth weight [MD = -5.50, 95% CI = -116.99 to 105.99, p = 0.92].

The investigators found compared with control group in pregnant women, no association between myo-inositol supplementation and macrosomia (a newborn with an excessive birth weight (≥4 kg)) [RR = 0.65, 95% CI = 0.20-2.11, p = 0.47].

The investigators concluded that myo-inositol supplementation reduces the incidence of gestational diabetes and preterm delivery in pregnant women.

Original title:
The efficacy of myo-inositol supplementation to prevent gestational diabetes onset: a meta-analysis of randomized controlled trials by Zhang H, Lv Y, […], Guo W.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29343138

Additional information of El Mondo:
Find more information/studies on inositol and pregnancy right here.

A review article (a collection of scientific studies on a specific topic) of randomized, placebo-controlled double blind clinical trials (RCTs) will answer the following question:
"Do taking dietary supplements make sense?" Yes for a positive conclusion and no for a negative conclusion.

Objectives:
Anemia is a major public health and nutritional problem in the world. Studies have reported the relationship between anemia during pregnancy and small for gestational age (SGA). Therefore, this meta-analysis (systematic review) has been conducted.

Does maternal anemia during pregnancy increase risk of SGA?

Study design:
This review article included 10 studies with a total of 620,080 pregnant women.

Results and conclusions:
The investigators found the overall relationship between maternal anemia during pregnancy and SGA was not significant [RR = 1.11, 95% CI = 0.99-1.24, p = 0.074].
Not significant means that there is no association with a 95% confidence.

The investigators found, however, a significantly increased risk of 11% [RR = 1.11, 95% CI = 1.00-1.22, p = 0.044] of SGA for materal anemia during first trimester. But this relationship was not significant in the second trimester [RR = 1.11, 95% CI = 0.85-1.18, p = 0.91].

The investigators concluded maternal anemia in the first trimester of pregnancy increases risk of small for gestational age (SGA).

Original title:
Maternal anemia during pregnancy and small for gestational age: a systematic review and meta-analysis by Badfar G, Shohani M, […], Azami M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29183181

Additional information of El Mondo:
Find more information/studies on anemia and pregnancy right here.
 

Objectives:
Cardiovascular risk factors are closely linked with dementia risk, but whether heart disease predisposes to dementia is uncertain. Therefore, this review article has been conducted.

Does heart disease increase risk of dementia?

Study design:
This review article included 16 studies (1,309,483 individuals) regarding coronary heart disease and 7 studies (1,958,702 individuals) about heart failure.

Results and conclusions:
The investigators found that a history of coronary heart disease was associated with a 27% increased risk of dementia [pooled relative risk = 1.27, 95% CI = 1.07-1.50, I2 = 80%].

The investigators found that a history of heart failure was associated with a 60% increased dementia risk [pooled relative risk = 1.60, 95% CI = 1.19-2.13, I2 = 59%].

The investigators found among 9 prospective population-based cohort studies, a significantly increased risk of 26% for dementia among patients with coronary heart disease [pooled relative risk = 1.26, 95% CI = 1.06-1.49, I2 = 0%].
Significantly means that there is an association with a 95% confidence.

The investigators found among 4 prospective population-based cohort studies, a significantly increased risk of 80% for dementia among patients with heart failure [pooled relative risk = 1.80, 95% CI = 1.41-2.31, I2 = 0%].
Significantly means it can be said with a 95% confidence that heart failure really increased the risk of getting dementia with 80%. 

The investigators concluded that both coronary heart disease and heart failure are associated with an increased risk of dementia.

Original title:
Coronary heart disease, heart failure, and the risk of dementia: A systematic review and meta-analysis by Wolters FJ, Segufa RA, […], Sedaghat S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29494808

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Find more information/studies on cohort/case-control study/significant, dementia and heart disease right here.
 

Objectives:
The aim of this review article is to summarize the evidence for the protective effectiveness of Bacillus Calmette-Guérin (BCG) vaccination against non-tuberculous mycobacterial disease.

Study design:
This review article included 10 studies, including almost 12 million participants.

Results and conclusions:
The investigators found in 3 cohort studies in industrialised countries that the incidence of non-tuberculous mycobacterial lymphadenitis was greatly reduced among BCG-vaccinated children compared to BCG-unvaccinated children, with a risk ratio of 0.04 [95% CI = 0.01 to 0.21].

The investigators found in 2 randomised trials in low-income countries, a significantly reduced risk of 50% [RR = 0.50, 95% CI = 0.37 to 0.69] against Buruli ulcer for the first 12 months following a BCG-vaccination, However, 4 case control studies had conflicting results.

The investigators found no studies had compared different BCG vaccine strains or the effect of revaccination.

The investigators concluded Bacillus Calmette-Guérin (BCG) vaccination protects against non-tuberculous mycobacterial disease. Therefore, the protective effect of BCG vaccination against non-tuberculous mycobacterial should be taken into consideration when deciding on recommendations for discontinuation of universal BCG vaccination programs and in assessing new vaccines designed to replace BCG.

Original title:
Does BCG Vaccination Protect Against Non-Tuberculous Mycobacterial Infection? A Systematic Review and Meta-Analysis by Zimmermann P, Finn A and Curtis N.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29635431

Additional information of El Mondo:
Find more information/studies on food fortification/malnutrition and study design/meta-analysis/significant right here.

Objectives:
Breast cancer is the most common cancer in women worldwide. The association between body mass index (BMI) and breast cancer risk has been paid more attention in the past few years, but the findings are still controversial. Therefore, this review article has been conducted.

Is there a relationship between BMI and breast cancer risk among women?

Study design:
This review article included 12 prospective cohort studies comprising 22,728,674 women.

All studies were published from 2004 to 2014, with the mean duration of follow-up varying from 4.29 to 10.8 years.
The sample size of included studies ranged from 15,054 to 1,222,630 women.
The Newcastle-Ottawa scale was applied to assess the quality of the included studies and the results showed all studies were of high quality, with a Newcastle-Ottawa scale score of ≥7.
There was no evidence of publication bias with Egger’s test [p = 0.74] and the funnel plot showed no sign of asymmetry by visual inspection.

Results and conclusions:
The investigators found overall results showed a weak positive association between a 5-unit increase in BMI and breast cancer risk, indicating that a 5 kg/m2 increase in BMI corresponded to a 2% increase in breast cancer risk [SRR = 1.02, 95% CI = 1.01-1.04, p 0.001, I2 = 74.2%, p = 0.00]. The results were statistically robust in sensitivity analyses.

The investigators found in subgroup analysis that higher BMI significantly reduced breast cancer risk with 2% among premenopausal women [SRR = 0.98, 95% CI = 0.96-0.99, p 0.001].

The investigators found there was evidence of a linear association between BMI and breast cancer risk in both premenopausal and postmenopausal women [p nonlinearity = 0.892 and p nonlinearity = 0.630, respectively].

The investigators concluded that every 5 kg/m² increase in BMI corresponds to a 2% increase in breast cancer risk in women. However, higher BMI is a protective factor of breast cancer risk for premenopausal women. Further studies are necessary to verify these findings and elucidate the pathogenic mechanisms.

Original title:
Association between body mass index and breast cancer risk: evidence based on a dose-response meta-analysis by Liu K, Zhang W, [...], Dai Z.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5783020/

Additional information of El Mondo:
Find more information/studies on cohort studies/significant and cancer right here.

Objectives:
Inflammatory markers are often elevated in patients with dementia, including Alzheimer's disease (AD). However, it remains unclear whether inflammatory markers are associated with the risk of developing dementia. Therefore, this review article has been conducted.

Do inflammatory markers increase risk of dementia and Alzheimer's disease (AD)?

Study design:
This review article included 13 studies in 6 countries.

Results and conclusions:
The investigators found a significantly increased risk of 37% [HR = 1.37, 95% CI = 1.05-1.78] for all-cause dementia for the highest vs. lowest quantile of C-reactive protein. However, this increased risk was not significant for Alzheimer's disease.

The investigators found a significantly increased risk of 40% [HR = 1.40, 95% CI = 1.13-1.73] for all-cause dementia for the highest vs. lowest quantile of interleukin-6. However, this increased risk was not significant for Alzheimer's disease.

The investigators found a significantly increased risk of 54% [HR = 1.54, 95% CI = 1.14-2.80] for all-cause dementia for the highest vs. lowest quantile of α1-antichymotrypsin. However, this increased risk was not significant for Alzheimer's disease.

The investigators found a significantly increased risk of 40% [HR = 1.40, 95% CI = 1.03-1.90] for all-cause dementia for the highest vs. lowest quantile of lipoprotein-associated phospholipase A2 activity. However, this increased risk was not significant for Alzheimer's disease.

The investigators concluded that several inflammatory markers are associated with an increased risk of all-cause dementia; however, these markers are not specific for Alzheimer's disease. Whether inflammatory markers closely involved in Alzheimer's disease pathology are associated with the risk of Alzheimer's disease remains to be elucidated.

Original title:
Inflammatory markers and the risk of dementia and Alzheimer's disease: A meta-analysis by Darweesh SKL, Wolters FJ, […], Hofman A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29605221

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Find more information/studies on cohort/case-control study/significant and dementia right here.
 

Objectives:
Malaria causes significant morbidity and mortality worldwide. There are several preventive measures that are currently employed, including insecticide-treated nets (ITNs, including long-lasting insecticidal nets and insecticidal-treated bed nets), indoor residual spraying (IRS), prophylactic drugs (PD) and untreated nets (UN). However, it is unclear which measure is the most effective for malaria prevention. Therefore, this review article has been conducted.

Which preventive measures are the most effective for malaria prevention?

Study design:
This review article included 30 studies from 1998-2016.

Results and conclusions:
The investigators found that the GPM framework led to a final ranking of effectiveness of measures in the following order from best to worst: prophylactic drugs (PD), insecticide-treated nets (ITNs, including long-lasting insecticidal nets and insecticidal-treated bed nets), indoor residual spraying (IRS) and untreated nets (UN), in comparison with no intervention (NI).

The investigators found, however, only ITN [RR = 0.49, 95% CI = 0.32-0.74] showed precision while other methods [PD: RR = 0.24, 95% CI = 0.004-15.43], IRS: RR = 0.55, 95% CI = 0.20-1.56] and UN: RR = 0.73, 95% CI = 0.28-1.90] demonstrating considerable uncertainty associated with their point estimates.

The investigators concluded current evidence is strong for the protective effect of insecticide-treated nets (including long-lasting insecticidal nets and insecticidal-treated bed nets), interventions in malaria prevention. Even though insecticide-treated nets are found to be the only preventive measure with statistical support for their effectiveness, the role of other malaria control measures may be important adjuncts in the global drive to eliminate malaria.

Original title:
Comparative effectiveness of malaria prevention measures: a systematic review and network meta-analysis by Wangdi K, Furuya-Kanamori L, […], Clements ACA.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5869791/

Additional information of El Mondo:
Find more information/studies on food fortification/malnutrition and study design/meta-analysis/significant right here.

Objectives:
Oxidative stress and inflammation are key parameters in developing metabolic disorders. Hence, antioxidant intake might be an appropriate approach. Several studies have evaluated the effect of coenzyme Q10 (CoQ10) supplementation on lipid profile among patients with metabolic diseases, though findings are controversial. Therefore, this review article has been conducted.

Does coenzyme Q10 supplementation improve lipid profile of patients with metabolic disorders?

Study design:
This review article included 21 RCTs with a total of 514 patients with metabolic disorders in the coenzyme Q10 supplementation group and 525 patients with metabolic disorders in the non-coenzyme Q10 supplementation group (control group).

Results and conclusions:
The investigators found coenzyme Q10 supplementation significantly reduced serum triglycerides levels of patients with metabolic disorders [SMD = -0.28, 95% CI = -0.56 to -0.005].

The investigators found coenzyme Q10 supplementation non-significantly reduced total-cholesterol levels of patients with metabolic disorders [SMD = -0.07, 95% CI = -0.45 to 0.31].

The investigators found coenzyme Q10 supplementation non-significantly increased LDL-cholesterol (bad cholesterol) levels of patients with metabolic disorders [SMD = 0.04, 95% CI = -0.27 to 0.36].

The investigators found coenzyme Q10 supplementation non-significantly increased HDL-cholesterol (good cholesterol) levels of patients with metabolic disorders [SMD = 0.10, 95% CI = -0.32 to 0.51].

The investigators concluded that coenzyme Q10 supplementation reduces serum triglycerides levels of patients with metabolic disorders. However, it has no effects on cholesterol levels.  

Original title:
The effects of coenzyme Q10 supplementation on lipid profiles among patients with metabolic diseases: a systematic review and meta-analysis of randomized controlled trials by Sharifi N, Tabrizi R, […], Asemi Z.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29623830

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A metabolic disorder occurs when the metabolism process fails and causes the body to have either too much or too little of the essential substances, namely carbohydrates, aminoacids, fatty acids and organic acids needed to stay healthy.

Metabolic disorders can take many forms. This includes:

• a disease in the liver, pancreas, endocrine glands or other organs involved in metabolism
• nutritional deficiencies
• a missing enzyme or vitamin that’s necessary for an important chemical reaction
• abnormal chemical reactions that hinder metabolic processes

Objectives:
Long-lasting insecticidal nets (LLINs) have been widely used as an effective alternative to conventional insecticide-treated nets (ITNs) for over a decade. Due to the growing number of field trials and interventions reporting the effectiveness of LLINs in controlling malaria, there is a need to systematically review the literature on LLINs and ITNs to examine the relative effectiveness and characteristics of both insecticide nettings. Therefore, this review article has been conducted.

The aim of this review article is to examine the relative effectiveness and characteristics of both long-lasting insecticidal nets (LLINs) and conventional insecticide-treated nets (ITNs)?

Study design:
This review article included 14 ITN articles and 12 LLIN articles since the year 2000 with a sample size of 154 subgroup observations, provides a comparison with findings in 1995.

14 ITN articles, 6 were randomized controlled trials and 6 were cross-sectional studies, that compared malaria prevalence between a group that slept under ITNs and a group that did not and 2 were cohort studies that analysed malaria rates within groups before and after using an ITN. The mean study size was 1,500 participants. Of all studies, 13% of observations were in children under 5 years of age.

Of the 12 LLIN articles, 5 were randomized controlled trials, 4 were cross-sectional studies and 3 were cohort studies. The mean study size was 1,728 participants. A total of 37% of LLIN observations looked at children under 5 years of age.

There was substantial heterogeneity in study characteristics and effect size.

Results and conclusions:
The investigators found that long-lasting insecticidal net use significantly reduced risk of malaria with 56% [overall OR = 0.44, 95% CI = 0.41-0.48, p 0.01, I2 = 96.5%].

The investigators found that conventional insecticide-treated net use significantly reduced risk of malaria with 41% [overall OR = 0.59, 95% CI = 0.57-0.61, p 0.01, I2 = 97.4%].

The investigators found meta-regression model confirmed that long-lasting insecticidal net use were significantly more effective than conventional insecticide-treated net use in the prevention of malaria, when controlling for other covariates.
The overall effectiveness of ITNs and LLINs in reducing the incidence of malaria was 41% and 56% respectively, when compared to people who used no form of netting. This implies that the efficacy of treated nets has improved substantially over the last decade, despite concerns that pyrethroid resistance in mosquitoes may compromise the ability of treated nets to kill mosquitoes.

The investigators found for both types of nets, protective efficacy was greater in high transmission areas when nets were used for an extended period. However, cross-sectional studies might overestimate the effect of the nets.

The investigators found that the results surprisingly suggested that nets were less effective in protecting children under the age of 5, which might be due to differences in child behaviour or inadequate coverage.

The investigators concluded that LLINs are statistically more effective than ITNs in preventing malaria, although the effectiveness of both has been substantially improved during the past decade. These findings support the importance of treated nets and the improvement from LLINs, in malaria control.

Original title:
A Meta-Regression Analysis of the Effectiveness of Mosquito Nets for Malaria Control: The Value of Long-Lasting Insecticide Nets by Yang GG, Kim D, [..], Paul CJ.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5877091/

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Objectives:
Despite high 1-dose vaccination coverage, breakthrough varicella infections still occur. Therefore, 2-dose vaccination is recommended to enhance the immune response to the virus. However, the reported incremental vaccine effectiveness (VE) of 2-dose vaccination varies widely among studies. Therefore, this review article has been conducted.

The aim of this review article is to determine the overall effectiveness, immunogenicity and safety of 1 vs. 2-dose varicella vaccination?

Study design:
This review article included studies published during 1995-2017.

Results and conclusions:
The investigators found that the incremental VE/efficacy of 2-dose varicella vaccination was 79% [95% CI = 56%-90%] in RCTs, 63% [95% CI = 36%-79%] in cohort studies and 81% [95% CI = 65%-90%] in case-control studies.

The investigators found regarding immunogenicity, the SMD of geometric mean titer and the pooled relative risk of seroconversion for 2-dose vs. 1-dose varicella vaccine were 562.44 [95% CI = 471.78-653.10] and 1.03 [95% CI = 1.02-1.04], respectively.

The investigators found that children who received second dose varicella vaccination had a significantly increased risk of grade 3 redness of 393% [RR = 4.93, 95% CI = 1.89-12.87] and a significantly increased risk of swelling of any intensity of 34% [RR = 1.34, 95% CI = 1.08-1.66].

The investigators concluded that 2-dose varicella vaccination results in higher levels of immunogenicity and provides superior protection than 1-dose vaccination. Safety profiles show 2-dose vaccination is well tolerated but the incidence of grade 3 redness and of any intensity is significantly higher.

Original title:
Effectiveness, immunogenicity and safety of one vs. two-dose varicella vaccination: a meta-analysis by Yin M, Xu X, […], Ni J.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29388450

Additional information of El Mondo:
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Objectives:
Observationally, homocysteine is associated with higher risk of diabetes. Folate, which reduces homocysteine, is promising for the prevention and treatment of diabetes. Previous meta-analysis (review) of 3 trials suggested folate might lower hemoglobin A1c (HbA1c). Therefore, this review article (meta-analysis) has been conducted.

Have folic acid supplementation positive effects on insulin resistance and glycemic control, like HbA1c level and fasting glucose level?

Study design:
This review article included 18 RCTs with in total of 21,081 people with/without diabetes.

Results and conclusions:
The investigators found that folic acid (folate) supplementation significantly reduced fasting glucose level with 0.15 mmol/L [95% CI = -0.29 to -0.01]. Significant means that there is an association with a 95% confidence.

The investigators found that folic acid (folate) supplementation significantly reduced homeostatic model assessment-insulin resistance (HOMA-IR) with 0.83 [95% CI = -1.31 to -0.34].

The investigators found that folic acid (folate) supplementation significantly reduced fasting insulin level with 1.94 μIU/mL [95% CI = -3.28 to -0.61].

The investigators found that folic acid (folate) supplementation had no clear effect on diabetes or HbA1c level.

The investigators concluded that folic acid (folate) supplementation reduces both fasting glucose level, fasting insulin level and homeostatic model assessment-insulin resistance (HOMA-IR) but it has no effect on diabetes or HbA1c level.

Original title:
The effects of folate supplementation on glucose metabolism and risk of type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials by Zhao JV, Schooling CM and Zhao JX.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29501221

Additional information of El Mondo:
Find more information/studies on diabetes and folic acid right here.

Patients with diabetes often have both an increased fasting glucose level, HOMA-IR value and fasting insulin level.

Objectives:
Malaria is a major public health problem in endemic countries including Sudan, where about 75% of populations are at risk. Due to widespread of chloroquine-resistant strains of Plasmodium falciparum, artemisinin-based combination therapy (ACT) is currently treatment of choice for malaria in the vast majority of malaria-endemic countries. Although there are several studies that were conducted to assess the efficacy of malaria treatment agents yielding different success rates in Sudan, there has been no systematic review and/or meta-analysis conducted to obtain strong evidence about the outcome of malaria treatment. Therefore, this review article has been conducted.

The aim of this review article is to obtain an overall stronger evidence of the outcomes of artemisinin-based combination therapy in the treatment of uncomplicated falciparum malaria from the existing literature in Sudan.

Study design:
This review article included 20 studies (artemisinin-based combination therapy in the treatment of uncomplicated falciparum malaria) with a total number of 4,070 participants that ranged from 30 patients to 1,463 patients.

Malaria treatment outcome was assessed using World Health Organization guidelines.
Adequate clinical and parasitological response was used to assess treatment success at the 28th day.

Results and conclusions:
The investigators found that treatment success of all combined studies was 98% [95% CI = 97.2-98.8%, p  0.001].

The investigators found that treatment success was higher in malaria patients treated with artemether + lumefantrine (AL) than patients treated with artesunate + sulfadoxine-pyrimethamine (AS + SP) [98.9%, 95% CI = 98.4-99.4% vs 97.1%. 95% CI = 95.5-98.6%, p  0.001].

The investigators found 11 studies reported adverse drug reactions (ADRs) to artemisinin-based combination therapy [184 participants out of 3957 (4.65%)]. The ADRs were mild and resolved spontaneously. There was no severe ADRs or deaths.

The investigators concluded that the overall success of treatment of uncomplicated falciparum malaria in Sudan is high (98%). Artemether + lumefantrine regimen shows higher efficacy compared to artesunate + sulfadoxine-pyrimethamine for treatment of uncomplicated falciparum malaria. The overall regimens are associated with mild low rates adverse drug reactions. Although the results of this review showed that the current malaria treatment agents in Sudan are effective and safe, greater efforts need be taken to develop new and more potent anti-malarial agents to prevent resistance which has been reported in other areas of the world.

Original title:
Efficacy and safety of artemisinin-based combination therapy for uncomplicated Plasmodium falciparum malaria in Sudan: a systematic review and meta-analysis by Adam I, Ibrahim Y and Gasim GI.

Link:
https://malariajournal.biomedcentral.com/articles/10.1186/s12936-018-2265-x

Additional information of El Mondo:
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Objectives:
β-amyloid (Aβ) accumulates abnormally to senile plaque which is the initiator of Alzheimer's disease (AD). As one of the Aβ-degrading enzymes, insulin-degrading enzyme (IDE) remains controversial for its protein level and activity in Alzheimer's brain. Therefore, this review article has been conducted.

Is there an association between insulin-degrading enzyme protein level and risk of Alzheimer's disease (AD)?

Study design:
This review article included 7 studies for IDE protein level (Alzheimer's disease cases = 293 and controls (persons without Alzheimer's disease)  = 126), 3 for mRNA level (Alzheimer's disease cases = 138 and controls = 81) and 3 for enzyme activity (Alzheimer's disease cases = 123 and controls = 75).

Results and conclusions:
The investigators found the insulin-degrading enzyme protein level was significantly lower in Alzheimer's disease patients than in controls [SMD = -0.47, 95% CI = -0.69 to -0.24, p 0.001].
But insulin-degrading enzyme mRNA and enzyme activity had no significant difference [SMD = 0.02, 95% CI = -0.40 to 0.43 and SMD = 0.06, 95% CI = -0.41 to 0.53, respectively].

The investigators found in subgroup analyses (to get more information) that insulin-degrading enzyme protein level was decreased in both cortex and hippocampus of Alzheimer's disease patients [SMD = -0.43, 95% CI = -0.71 to -0.16, p = 0.002 and SMD = -0.53, 95% CI = -0.91 to -0.15, p = 0.006 respectively].
However, insulin-degrading enzyme mRNA was higher in cortex of Alzheimer's disease patients [SMD = 0.71, 95% CI = 0.14 to 1.29, p = 0.01] but not in hippocampus [SMD = -0.26, 95% CI [= -0.58 to 0.06].

The investigators concluded that Alzheimer's disease patients have lower insulin-degrading enzyme protein level. Further relevant studies are still needed to verify whether insulin-degrading enzyme is one of the factors affecting Aβ abnormal accumulation and throw new insights for Alzheimer's disease detection or therapy.

Original title:
Characteristics of Insulin-degrading Enzyme in Alzheimer's Disease: A Meta-analysis by Zhang H, Liu D, […], Zhou H.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29357797

Additional information of El Mondo:
Find more information/studies on cohort/case-control study/significant and dementia right here.
 

Objectives:
Multiple epidemiologic studies have evaluated the relationship between dietary cholesterol and lung cancer risk, but the association is controversial and inconclusive. Therefore, this review article has been conducted.

Does consumption of dietary cholesterol increase risk of lung cancer?

Study design:
This review article included 10 case-control studies (6,894 lung cancer cases and 29,736 controls/persons with no lung cancer) and 6 cohort studies (1,769 lung cancer cases among 241,920 participants).

The Newcastle-Ottawa Scale scores for the included studies ranged from 6 to 9 and all studies were deemed to be of high quality (≥6).

There was no evidence of publication bias observed. Case-control studies: Egger’s test, p = 0.737, Begg’s test, p = 0.213 and cohort studies: Egger’s test, p = 0.459, Begg’s test, p = 1.000.

Results and conclusions:
The investigators found in case-control studies that a high dietary cholesterol intake significantly increased lung cancer risk with 70% [OR = 1.70, 95% CI = 1.43-2.03, I2 = 42.3%, p = 0.067]. No significant change in the result was found in the sensitivity analysis.

The investigators found in cohort studies no association between a high dietary cholesterol intake and lung cancer risk [RR = 1.08, 95% CI = 0.94-1.25, I2 = 0.0%, p = 0.833]. No significant change in the result was found in the sensitivity analysis.

The investigators found in 6 case-control studies that a high dietary total fat intake significantly increased lung cancer risk with 64% [OR = 1.64, 95% BI = 1.16-2.33, I2 = 68.7%, p = 0.004]. No significant change in the result was found in the sensitivity analysis.

The investigators concluded that a high dietary cholesterol intake might increase lung cancer risk. Might increase because the increased risk was not significant in cohort studies. Therefore, carefully designed and well-conducted cohort studies are needed to identify the association between dietary cholesterol and lung cancer risk.

Original title:
Dietary Cholesterol Intake and Risk of Lung Cancer: A Meta-Analysis by Lin X, Liu L, […], Lian X.

Link:
http://www.mdpi.com/2072-6643/10/2/185/htm

Additional information of El Mondo:
Find more information/studies on cohort studies/significant, cholesterol consumption and cancer right here.

A high dietary cholesterol intake is an intake of more than 200-300 mg cholesterol per day.

The result of a review article is only reliable when the result is also significant in cohort studies (thus not only significant in case-control studies).
 

Objectives:
Older adults experience age-related physiological changes that affect body weight and body composition. In general, nutrition and exercise have been identified as potent stimulators of protein synthesis in skeletal muscle. Milk proteins are excellent sources of all the essential amino acids and may represent an ideal protein source to promote muscle anabolism in older adults undergoing resistance training. However, several randomized control trials (RCTs) have yielded mixed results on the effects of milk proteins supplementation in combination with resistance training on body weight and composition. Therefore, this review article has been conducted.

Does supplementation of milk protein alone or in combination with resistance training, increase fat-free mass in older adults (age ≥ 60 years)?

Study design:
This review article included 10 RCTs involving 574 participants (mean age range from 60 to 80.8 years).

There was no statistical evidence of publication bias among the studies.

Results and conclusions:
The investigators found overall, the combination of milk proteins supplementation and resistance training had no significant effect on fat mass [0.30, 95% CI = -0.25 to 0.86 kg] or body weight [1.02, 95% CI = -0.01 to 2.04 kg].

The investigators found, however, a positive effect of milk proteins supplementation paired with resistance training on fat-free mass [0.74, 95% CI = 0.30 to 1.17 kg].

The investigators found greater fat-free mass gains were observed in studies that included more than 55 participants [0.73, 95% CI = 0.30 to 1.16 kg] and in studies that enrolled participants with aging-related medical conditions [1.60, 95% CI = 0.92 to 2.28 kg].

The investigators concluded supplementation of milk protein, in combination with resistance training, is effective to elicit fat-free mass gain in older adults (age ≥ 60 years).

Original title:
Effects of Milk Proteins Supplementation in Older Adults Undergoing Resistance Training: A Meta-Analysis of Randomized Control Trials by Hidayat K, Chen GC, […], Qin LQ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29380851

Additional information of El Mondo:
Find here more information/studies about sport nutrition, protein and elderly.

Objectives:
The anti-hepatitis B immunization campaigns launched in the early 1990s were a major public health breakthrough and targeted various populations (at-risk adults, newborns, adolescents). However, debate is still active about a possible link between this vaccine and central demyelination. Therefore, this review article (meta-analysis) has been conducted.

Do hepatitis B vaccination increase risk of central demyelination?

Study design:
This review article included 13 epidemiologic studies with a control group.

Results and conclusions:
The investigators found none of the pooled risk estimates for either multiple sclerosis or central demyelination following anti-hepatitis B immunization reached statistical significance.

The investigators found a non-significantly increased risk of 19% [adjusted risk ratio = 1.19, 95% CI = 0.93 to 1.52] for multiple sclerosis following hepatitis B vaccination.

The investigators found a non-significantly increased risk of 25% [adjusted risk ratio = 1.25, 95% CI = 0.97 to 1.62] for central demyelination following hepatitis B vaccination.

The investigators concluded that there is no evidence of an association between hepatitis B vaccination and central demyelination.

Original title:
Hepatitis B vaccination and the putative risk of central demyelinating diseases - A systematic review and meta-analysis by Mouchet J, Salvo F, […], Bégaud B.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29454521

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Objectives:
The increasing prevalence of diabetes in the United Kingdom and worldwide calls for new approaches to its management and diets with low glycaemic index have been proposed as a useful means for managing glucose response. However, there are conflicting reports and differences in the results of studies in terms of their effectiveness. Furthermore, the impact of low-glycaemic index diets (low GI-diets) and their long-term use in patients with type 2 diabetes remains unclear. Therefore, this review article (meta-analysis) has been conducted.

Do patients with type 2 diabetes mellitus benefit from low-GI diets?

Study design:
This review article included 6 RCTs.

Results and conclusions:
The investigators found in 2 RCTs that low-glycaemic index (low-GI) diet resulted in a significant improvement in glycated haemoglobin (HbA1c) [0.05]:
low-GI diet Δ = -0.5% [95% CI = -0.61% to -0.39%] vs. high-cereal fibre diet Δ = -0.18% [95% CI = -0.29% to -0.07%] and;
low-GI legume diet Δ = -0.5% [95% = -0.6% to -0.4%] vs. high-wheat fibre diet Δ = -0.3% [95% Cl = -0.4 to -0.2%].

The investigators found in 4 RCTs significant improvements in fasting blood glucose in low-GI diets compared to higher-GI diets or control:
low-GI diet = [150.8 ± 8.7] vs. higher-GI diet = [157.8 ± 10.4 mg/dL, mean ± SD, p = 0.43];
low-GI diet = [127.7] vs. high-cereal fibre diet = [136.8 mg/dL, p = 0.02];
low-GI diet = [6.5 (5.6-8.4)] vs. standard diabetic diet = [6.7 (6.1-7.5 mmol/L), median and interquartile range p > 0.05] and;
low-GI diet = [7.3 ± 0.3] vs. conventional carbohydrate exchange diet = [7.7 ± 0.4 mmol/L, mean ± SEM (Standard Error of Mean), p 0.05].

The investigators concluded that the low-GI diet is more effective in controlling glycated haemoglobin (HbA1c) and fasting blood glucose compared with a higher-GI diet or control in patients with type 2 diabetes. It will useful to evaluate the long-term effectiveness of low-glycaemic index diet in patients with type 2 diabetes.

Original title:
The Effect of Dietary Glycaemic Index on Glycaemia in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Ojo O, Ojo OO, [...], Wang XH.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872791/

Additional information of El Mondo:
Find more information/studies on diabetes and GI-diets right here.

A low-GI diet is a diet with a lot of products/meals with a low GI.
Products/meals with a low GI are products/meals with a GI-number of 55 or less.
In daily life, products/meals with a low GI contain at least 1.5 grams fiber per 100 kcal. These products and meals contain at least 1.5 grams fiber per 100 kcal.
 

Objectives:
Type 2 diabetes mellitus (T2DM) is one of the most important public health issues. Vitamin K supplementation might have favorable effect on risk factors of T2DM. Therefore, this review article (meta-analysis) has been conducted.

Have vitamin K supplementation favorable effects on risk factors of type 2 diabetes mellitus?

Study design:
This review article included 5 RCTs with in total of 533 participants.

There was no evidence of publication bias.

Results and conclusions:
The investigators found overall, meta-analysis did not show any beneficial effect of vitamin K supplementation on both:
-fasting blood sugar levels [-0.91 mg/dL, 95% CI = -2.57 to 0.76, p = 0.28];
-fasting insulin levels [-0.35 μIU/mL, 95% CI = -1.70 to 1.00, p = 0.61];
-HOMA-IR [-0.06, 95% CI = -0.32 to -0.19, p = 0.63] and
-2-h oral glucose tolerance test [-4.00 mg/dL, 95% CI = -20.00 to 11.99, p = 0.62].

The investigators found sensitivity analysis showed that overall estimates were not affected by elimination of any study.

The investigators concluded that vitamin K supplementation has no significant effect on glycemic control in healthy subjects. However, further studies should be performed on diabetic and pre-diabetic patients to determine the effect of vitamin K supplementation on impaired glycemic control.

Original title:
Effect of Vitamin K Supplementation on Glycemic Control: A Systematic Review and Meta-Analysis of Clinical Trials by Shahdadian F, Mohammadi H and Rouhani M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29523009

Additional information of El Mondo:
Find more information/studies on diabetes and vitamin K right here.
 

Objectives:
The actual effects of L-carnitine administration on leptin serum level is inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does L-carnitine supplementation reduce leptin serum level?

Study design:
This review article included 7 RCTs with 325 cases (group with L-carnitine administration) and 330 controls (group without L-carnitine administration).

Subgroup analysis to find the sources of heterogeneity showed that L-carnitine dosage [ 2 g: I2 = 00.0%, p = 0.408] and study population [diabetes: I2 = 46.7%, p = 0.153 and non-diabetes: I2 = 15.1%, p = 0.317] were the potential sources of heterogeneity.

Results and conclusions:
The investigators found that L-carnitine supplementation had no significant effect on serum leptin concentrations [WMD = -0.565 ng/mL, 95% CI = -2.417 to 1.287, p = 0.550, I2 = 84.3%, p  0.0001].

The investigators found in subgroup analysis that  ≥ 2 mg L-carnitine supplementation significantly reduced serum leptin concentrations [WMD = -2.742 ng/mL, 95% CI = -3.039 to -2.444, p  0.001].

The investigators found in subgroup analysis that L-carnitine supplementation significantly reduced serum leptin concentrations in diabetic patients [WMD = -2.946 ng/mL, 95% CI = -3.254 to -2.638, p  0.001].

The investigators found in subgroup analysis that L-carnitine supplementation during 12 weeks significantly reduced serum leptin concentrations [WMD = -2.772 ng/mL, 95% CI = -3.073 to -2.471, p  0.001].

The investigators concluded that at least 3 mg L-carnitine per day in the course of 12 weeks reduce serum leptin concentrations, especially in diabetic patients.

Original title:
The effect of L-carnitine supplementation on serum leptin concentrations: a systematic review and meta-analysis of randomized controlled trials by Nazary-Vannani A, Ghaedi E, […], Varkaneh HK.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29453657

Additional information of El Mondo:
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L-carnitine is a non-essential amino acid, which is also found in foods.