Nutrition and health

Objectives:
Does type 1 diabetes mellitus (T1DM) decrease bone mineral density (BMD) in children and adolescents?

Study design:
This review article included 9 cross-sectional studies with a total of 1,522 children and adolescents.

Funnel plot and the Egger test did not reveal significant publication bias.

Results and conclusions:
The investigators found a significant decrease in bone mineral density Z-score in the whole body [pooled WMD = -0.47, 95% CI = -0.92 to -0.02, I2 = 80.2%] and lumbar spine [pooled WMD = -0.41, 95% CI = -0.69 to -0.12, I2 = 80.3%] in children and adolescents with type 1 diabetes mellitus, which was consistent in published studies from Asia and South America, but inconsistent in the North America and Europe.
Sensitivity analyses did not modify these findings.

The investigators found, importantly, the differences in bone mineral density Z-scores were independent of age, level of glucose control (HbA1c) and prepubertal stage.

The investigators concluded type 1 diabetes mellitus (T1DM) decreases bone mineral density (BMD) Z-scores in the whole body and lumbar spine in children and adolescents.

Original title:
Association between type 1 diabetes mellitus and reduced bone mineral density in children: a meta-analysis by Zhu Q, J Xu J, […], Shi J.

Link:
https://pubmed.ncbi.nlm.nih.gov/33404757/  

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

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/

Additional information of El Mondo:
Find more information/studies on omega-3 and fish consumption and cardiovascular diseases right here.

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/

Additional information of El Mondo:
Find here more information/studies about RCTs/significant and chronic diseases.

Objectives:
Undernutrition is one of the most common problems among people living with Human Immunodeficiency Virus (HIV), contributing to premature death and the development of comorbidities within this population. In Sub-Saharan Africa (SSA), the impacts of these often inter-related conditions appear in a series of fragmented and inconclusive studies. Therefore, this review article has been conducted.

Does undernutrition increase the risk of mortality and morbidity among adults living with HIV in Sub-Saharan Africa (SSA)?

Study design:
This review article included 53 studies (cohort and cross-sectional studies) with a total of 367,680 adults living with HIV (76.2% females).
Publication year of the included studies ranged from 2006 to 2019.
The sample size of the included studies ranged from 71 in Kenya to 68,378 in Tanzania. Most were cohort studies (n = 47, 88.7%). About 63.8% of the included cohort studies had a follow-up period of less than 5 years for mortality and/or less than 2 years for morbidities.
NOS quality scores ranged from 5 to 9 for cohort studies and 8 to 10 for cross-sectional studies.
The mean quality score of the included studies was 7.34 [SD = 0.14].
There was no publication bias.

Results and conclusions:
The investigators found a meta-analysis of 23 cohort studies (involving 125,790 individuals) indicated that undernutrition significantly [AHR = 2.1, 95% CI = 1.8 to 2.4, I2 = 66.4%, p  0.001] increased the risk of mortality among adults living with HIV, while severely undernourished adults living with HIV were at higher risk of death [AHR = 2.3, 95% CI = 1.9 to 2.8) as compared to mildly undernourished adults living with HIV.

The investigators found, furthermore, the pooled estimates of 10 cohort studies (involving 104,387 adults living with HIV) revealed that undernutrition significantly increased the risk of developing tuberculosis [AHR = 2.1, 95% CI = 1.6 to 2.7, I2 = 75.2%, p  0.001] among adults living with HIV.

The investigators concluded that undernutrition has significant effects on mortality and morbidity among adults living with HIV. As the degree of undernutrition became more severe, mortality rate also increased. Therefore, these findings may be used to update the nutritional guidelines used for the management of people living with HIV (PLHIV), by different stakeholders, especially in limited-resource settings.

Original title:
Effects of undernutrition on mortality and morbidity among adults living with HIV in sub-Saharan Africa: a systematic review and meta-analysis by Alebel A, Demant D, […], Sibbritt D.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7780691/

Additional information of El Mondo:
Find more information/studies on food fortification/malnutrition right here.

Objectives:
Although several epidemiological studies have investigated associations between poultry and fish consumption and pancreatic cancer (PC) risk, these findings have been inconsistent. Therefore, this review article has been conducted.

Do high dietary poultry or fish intakes increase risk of pancreatic cancer?

Study design:
This review article included 25 studies (cohort studies and case-control studies).

Results and conclusions:
The investigators found for the highest vs. lowest poultry intake category a significantly increased risk of 14% for pancreatic cancer [pooled RR = 1.14, 95% CI = 1.02 to 1.26] in cohort studies.
Significant because RR of 1 was not found in the 95% CI of 1.02 to 1.26. RR of 1 means no risk/association.

The investigators found there was no association between fish intake and pancreatic cancer risk [RR = 1.00, 95% CI = 0.93 to 1.07].
No association because RR of 1 was found in the 95% CI of 0.93 to 1.07. RR of 1 means no risk/association.

The investigators concluded that large amount of poultry intake increases pancreatic cancer risk, while fish intake is unlikely to be linked to pancreatic cancer risk. These findings require further investigation, particularly between poultry and pancreatic cancer.

Original title:
Poultry and Fish Intake and Pancreatic Cancer Risk: A Systematic Review and Meta-Analysis by Gao Y, Ma Y, […], Wang X.

Link:
https://pubmed.ncbi.nlm.nih.gov/33432844/

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

Objectives:
Does dietary acrylamide intake increase risk of breast, endometrial and ovarian cancer?

Study design:
This review article included 14 prospective cohort studies.

Results and conclusions:
The investigators found no significant association between dietary acrylamide intake and the risk of breast [RR = 0.95, 95% CI = 0.90 to 1.01], endometrial [RR = 1.03, 95% CI = 0.89 to 1.19] and ovarian cancers [RR = 1.02, 95% CI = 0.84 to 1.24].
In addition, no significant association between dietary acrylamide intake and the risk of breast, endometrial and ovarian cancers in different subgroup analyses by smoking status, menopausal status, BMI status and different types of breast cancer.

The investigators concluded there is no significant association between dietary acrylamide intake and the risk of breast, endometrial and ovarian cancers.

Original title:
Dietary acrylamide intake and risk of women's cancers: a systematic review and meta-analysis of prospective cohort studies by Benisi-Kohansal S, Salari-Moghaddam A, […], Esmaillzadeh A.

Link:
https://pubmed.ncbi.nlm.nih.gov/33413725/

Additional information of El Mondo:
Find more information/studies on breast cancer right here.

Acrylamide is a chemical that naturally forms in starchy food products during high-temperature cooking processes, such as frying, roasting and baking. Acrylamide in food forms from sugars and an amino acid that are naturally present in food.
 

Objectives:
Although exercise can improve insulin sensitivity, no adequate synthesis exists of exercise intervention studies with regard to their effect on insulin sensitivity. Therefore, this review article (meta-analysis) has beeen conducted.

Does exercise improve insuline sensitivity?

Study design:
This review article included data found across 2509 subjects (115 samples, 78 reports).
The median of mean age was 43 years.
The median of mean preintervention fasting insulin was 8 mU/L.

Results and conclusions:
The investigators found the overall mean effect size for 2-group postintervention comparisons was 0.38 [95% CI = 0.25-0.51, I2 = 0%] and for 2-group pre-post comparisons was 0.43 [95% CI = 0.30-0.56, I2 = 52%].

The investigators found higher mean insulin sensitivity for treatment than control subjects.

The investigators found the postintervention mean of 0.38 was consistent with treatment subjects ending studies with a mean fasting insulin of 6.8 mU/L if control participants’ mean fasting insulin were 7.9 mU/L.
Exploratory moderator analyses did not document different insulin sensitivity effect sizes across intervention characteristics or sample attributes.

The investigators concluded exercise is a valuable primary care and community health strategy for healthy adults to improve insulin sensitivity and lower the risk for diabetes conferred by insulin resistance.

Original title:
Insulin Sensitivity Following Exercise Interventions: Systematic Review and Meta-Analysis of Outcomes Among Healthy Adults by Conn VS, Koopman RJ, […], Hafdahl AR.

Link:
http://journals.sagepub.com/doi/pdf/10.1177/2150131913520328

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

Objectives:
Evidence shows cruciferous vegetables exhibit chemoprotective properties, commonly attributed to their rich source of isothiocyanates. However, epidemiological data examining the association between cruciferous vegetable intake and colorectal neoplasms have been inconclusive. Therefore, this review article (meta-analysis) has been conducted.

Does cruciferous vegetable intake decrease colon cancer risk?

Study design:
This review article included 33 articles.
Subgroup analysis for individual cruciferae types (n = 8 studies) and GST polymorphism (n = 8 studies) were performed. Pooled adjusted odds ratios (ORs) comparing highest and lowest categories of dietary pattern scores were calculated.

Results and conclusions:
The investigators found when comparing highest with lowest categorie, cruciferous vegetable intake significantly reduced risk of colon cancer with 16% [OR = 0.84, 95% CI = 0.72-0.98, p value heterogeneity 0.001].

The investigators found when comparing highest with lowest categorie, broccoli intake significantly reduced risk of colorectal neoplasms with 20% [OR = 0.80, 95% CI = 0.65-0.99, p value heterogeneity = 0.02].

The investigators found stratification by GST genotype showed that the GSTT1 null genotype confered a reduction in colorectal neoplasms risk of 22% [OR = 0.78, 95% CI = 0.64-0.95, p value heterogeneity = 0.32].

The investigators concluded this meta-analysis provides support to the hypothesis that cruciferous vegetable intake protects against cancer of the colon. This meta-analysis also demonstrates the significance of gene-diet interactions and the importance of assessing individual cruciferous vegetables.

Original title:
Cruciferous vegetables and risk of colorectal neoplasms: a systematic review and meta-analysis by Tse G and Eslick GD.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/24341734

Additional information of El Mondo:
Find more studies/information on colon cancer and cruciferous vegetable intake right here.

Objectives:
Does physical activity reduce gastric cancer risk?

Study design:
This review article included 7 cohort studies (with mean reported follow-up ranging from 6 to 18.8 years) and 9 case control studies reporting 11,111 cases of gastric cancer among 1,606,760 patients.

There was no evidence of publication bias, both quantitatively [Begg and Mazumdar rank correlation test, p = 0.62] and qualitatively, on visual inspection of the funnel plot.

Results and conclusions:
The investigators found the risk of gastric cancer was 21% [OR = 0.79, 95% CI = 0.71-0.87, I2 = 55%]  lower among the most physically active people as compared with the least physically active people, after adjustment for important confounders, including age, obesity, and other risk factors for gastric cancer (smoking, alcohol, dietary patterns and socioeconomic status).
This protective effect was seen for gastric cancers in the cardia [OR = 0.80, 95% CI = 0.63-1.00, 4 studies] and distal stomach [OR = 0.63, 95% CI = 0.52-0.76, 5 studies].

The investigators found increasing physical activity was associated with a reduced risk of gastric cancer in both men [OR = 0.86, 95% CI = 0.75-0.99, 10 studies] and women [OR = 0.72, 95% CI = 0.55-0.94, 3 studies].

The investigators found in 12 studies that increased recreational physical activity showed an 18% reduction in gastric cancer risk [OR = 0.82, 95% CI = 0.72-0.94].

The investigators found the effect size was significantly smaller in high-quality studies [OR = 0.86, 95% CI = 0.75-0.99, 6 studies] as compared with low-quality studies [OR = 0.74, 95% CI = 0.69-0.81, 10 studies]. The results were consistent across sex, study quality, study design and geographic location.

The investigators concluded physical activity - especially recreational physical activity - is associated with reduced risk of gastric cancer. Lifestyle interventions focusing on increasing physical activity may decrease the global burden of gastric cancer, in addition to a myriad of other health benefits with being physically active, which include cardiovascular, metabolic and psychologic wellbeing.

Original title:
Physical Activity Is Associated with Reduced Risk of Gastric Cancer: A Systematic Review and Meta-analysis by Singh S, Varayil JE, […], Iyer PG.

Link:
http://cancerprevention.aacrjournals.org/content/7/1/12.abstract

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

Objectives:
Previous meta-analyses identified an inverse association of coffee consumption with the risk of type 2 diabetes. However, an updated meta-analysis is needed because new studies comparing the trends of association for caffeinated and decaffeinated coffee have since been published. Therefore, this review article has been conducted.

Does coffee intake reduce type 2 diabetes risk in a dose-response manner?

Study design:
This review article included 28 prospective cohort studies with 1109272 study participants and 45335 cases of type 2 diabetes. The follow-up duration ranged from 10 months to 20 years.

Results and conclusions:
The investigators found for compared with no or rare coffee consumption, a significant reduced risk of type 2 diabetes of:
8% [RR = 0.92, 95% CI = 0.90-0.94] for 1 cup/day;
15% [RR= 0.85, 95% CI = 0.82-0.88] for 2 cups/day;
21% [RR = 0.79, 95% CI = 0.75-0.83] for 3 cups/day;
25% [RR = 0.75, 95% CI = 0.71-0.80] for 4 cups/day;
29% [RR = 0.71, 95% CI = 0.65-0.76] for 5 cups/day and;
33% [RR = 0.67, 95% CI = 0.61-0.74] for 6 cups/day.

The investigators found a significant decreased risk of type 2 diabetes of 9% [RR = 0.91, 95% CI = 0.89-0.94] for an increasement of 1 cup/day caffeinated coffee and 6% [RR = 0.94, 95% CI = 0.91-0.98] for an increasement of 1 cup/day decaffeinated coffee [p for difference = 0.17].

The investigators concluded coffee consumption is inversely associated with the risk of type 2 diabetes in a dose-response manner. Both caffeinated and decaffeinated coffee is associated with reduced diabetes risk.

Original title:
Caffeinated and decaffeinated coffee consumption and risk of type 2 diabetes: a systematic review and a dose-response meta-analysis by Ding M, Bhupathiraju SN, […], Hu FB.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/24459154

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

Objectives:
The prevalence of obesity and diabetes is increasing among children, adolescents and adults. Although estimates of the efficacy of exercise training on fasting insulin and insulin resistance have been provided for adults, similar estimates have not been provided for youth. Therefore, this review article has been conducted.

Study design:
This review article included 24 trials.

Results and conclusions:
The investigators found a small to moderate effect for exercise training on fasting insulin and improving insulin resistance in youth [Hedges’ d effect size = 0.48, 95% CI = 0.22-0.74, p 0.001 and 0.31, 95% CI = 0.06-0.56, p 0.05, respectively].

The investigators concluded there is evidence to support the use of exercise training in the prevention and treatment of type 2 diabetes in youth.

Original title:
Exercise and Insulin Resistance in Youth: A Meta-Analysis by Fedewa MV, Gist NH, […], Dishman RK.

Link:
http://www.pediatricsdigest.mobi/content/133/1/e163.abstract

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

Objectives:
The association of red meat consumption with the risk of stomach cancer has been reported by many studies, with inconclusive results. Therefore, this review article has been conducted.

Does a high red meat consumption increase stomach cancer risk?

Study design:
This review article included a total of 18 studies (cohort and case-control studies) involving 1,228,327 subjects.

Results and conclusions:
The investigators found for the highest versus lowest categories of red meat intake a significant increased risk of 37% for gastric cancer [pooled RR = 1.37, 95% CI = 1.18-1.59, I2 = 67.6%, p 0.001].

The investigators found in population-based case-control studies, a significant increased risk of 58% for gastric cancer [pooled RR = 1.58, 95% CI = 1.22-2.06, I2 = 73.0%, p 0.001].

The investigators found in hospital-based case-control studies, a significant increased risk of 63% for gastric cancer [pooled RR = 1.63, 95% CI = 1.38-1.92, I2 = 19.1%, p = 0.284].

The investigators found, however, no association among cohort studies [RR = 1.00, 95% CI = 0.83-1.20, I2 = 33.9%, p = 0.158].

The investigators found the significant association was also presented in the subgroup analysis by geographic area (Asia, Europe), publication year (≥2000), sample size (1,000, ≥1,000) and quality score (7 stars, ≥7 stars).

The investigators found in dose-response analysis that every 100 g/day increment in red meat intake significant increased gastric cancer risk with 17% [RR = 1.17, 95% CI = 1.05-1.32].

The investigators found in linear regression model that the risk of gastric cancer increased with increasing level of red meat consumption.

The investigators concluded that a increased intake of red meat might be a risk factor for stomach cancer. Might be because the risk was not significant among cohort studies. Therefore, further larger prospective cohort studies are warranted to verify this association.

Original title:
Red meat consumption and stomach cancer risk: a meta-analysis by Song P, Lu M, […], Zhao Q.

Link:
https://link.springer.com/article/10.1007/s00432-014-1637-z

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

Objectives:
The association between meat consumption and the risk of hepatocellular carcinoma (HCC) is still inconclusive. Therefore, this review article has been conducted.

Does meat consumption increase risk of hepatocellular carcinoma?

Study design:
This review article included 7 cohort studies and 10 case-control studies.

Results and conclusions:
The investigators found for the highest vs. lowest consumption levels a non-significant increased risk for hepatocellular carcinoma of 10% [RR = 1.10, 95% CI = 0.85-1.42] for red meat, a non-significant increased risk of 1% [RR = 1.01, 95% CI = 0.79-1.28] for processed meat and a non-significant decreased risk of 3% [RR = 0.97, 95% CI = 0.85-1.11] for total meat. Non-significant means, there is no association with a 95% confidence.

The investigators found for the highest vs. lowest consumption levels a significant decreased risk for hepatocellular carcinoma of 31% [RR = 0.69, 95% CI = 0.58-0.81] for white meat and a significant decreased risk of 22% [RR = 0.78, 95% CI = 0.67-0.90] for fish. The results remained quite stable after stratification by the confounding factors.
Significant means, there is an association with a 95% confidence.

The investigators concluded a high level of white meat or fish consumption reduces the risk of hepatocellular carcinoma, while intake of red meat, processed meat or total meat is not associated with hepatocellular carcinoma risk. These results suggest that dietary intervention may be a promising approach for prevention of hepatocellular carcinoma, which still need to be confirmed by further well-designed prospective studies and experimental research.

Original title:
Systematic review with meta-analysis: meat consumption and the risk of hepatocellular carcinoma by Luo J, Yang Y, [...], Zhu Y.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/24588342

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

A review article of cohort studies or case-control studies will answer the following question:
"Should I change my diet?".

Objectives:
Is there an association between meat intake and risk of esophageal cancer?

Study design:
This review article included 7 cohort studies and 28 case-control studies.

Results and conclusions:
The investigators found for the highest versus lowest total meat consumption categories a non-significant increased risk of 19% [95% CI = 0.98-1.46] for esophageal cancer.

The investigators found for the highest versus lowest red meat consumption categories a significant increased risk of 55% [95% CI = 1.22-1.96] for esophageal cancer.

The investigators found for the highest versus lowest processed meat consumption categories a significant increased risk of 33% [95% CI = 1.04-1.69] for esophageal cancer.

The investigators found for the highest versus lowest white meat consumption categories a significant decreased risk of 28% [95% CI = 0.60-0.86] for esophageal cancer.

The investigators found for the highest versus lowest poultry consumption categories a significant decreased risk of 17% [95% CI = 0.72-0.96] for esophageal cancer.

The investigators found for the highest versus lowest fish consumption categories a non-significant decreased risk of 5% [95% CI = 0.76-1.19] for esophageal cancer.

The investigators found when stratified by histological subtype, positive associations among esophageal squamous cell carcinoma and red meat, white meat and poultry and esophageal adenocarcinoma with total meat and processed meat.

The investigators concluded red meat and processed meat consumption increase risk of esophageal cancer, while white meat and poultry decrease risk of esophageal cancer. Fish consumption is not associated with incidence of esophageal cancer.

Original title:
Meat consumption is associated with esophageal cancer risk in a meat- and cancer-histological-type dependent manner by Zhu HC, Yang X, […], Sun XC.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/24395380

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

Objectives:
Previous observational studies regarding the existence of an association between folate intake and the risk of breast cancer have been inconsistent. Therefore, this review article has been conducted.

Does a higher dietary folate intake reduce breast cancer risk?

Study design:
This review article included 14 prospective cohort studies that reported data on 677,858 individuals.
The participant follow-up period ranged 4.7-17.4 years and the number of individuals per study ranged 11,699-88,818.
There was no publication bias.

Results and conclusions:
The investigators found no association between dietary folate intake and breast cancer risk for highest versus lowest category  [RR =  0.97, 95% CI = 0.90-1.05, p  = 0.451, I2 =  57.5%, p = 0.004].

The investigators found dose-response meta-analysis findings showed no association between the risk of breast cancer and a 100 µg/day increase in dietary folate intake [RR = 0.99, 95% CI = 0.98-1.01, p = 0.361, I2 = 66.2%, p 0.001].

The investigators found evidence of a nonlinear relationship between dietary folate intake and the risk of breast cancer.

A daily dietary folate intake of 200-320 µg was associated with a reduced risk of breast cancer. However, daily folate intake levels >400 µg was associated with a increased risk of breast cancer.

The investigators found overall folate intake level was associated with a reduced breast cancer risk of 36% if the patients had a daily alcohol intake >10 g [RR for highest versus lowest category = 0.64, 95% CI = 0.43-0.97].

The investigators concluded there are no effects of increased dietary folate intake on the incidence of breast cancer. But, a daily dietary folate intake of 200-320 µg was associated with a reduced risk of breast cancer. However, daily folate intake levels >400 µg was associated with a increased risk of breast cancer. Future studies should focus on specific populations in order to analyze primary breast cancer prevention.

Original title:
Folate Intake and the Risk of Breast Cancer: A Dose-Response Meta-Analysis of Prospective Studies by Zhang YF, Shi WW, […], Zhou YH.

Link:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4059748/

Additional information of El Mondo:
Find more studies/information on folate intake and breast cancer right here.
 

Objectives:
Increasing evidence suggests that the Mediterranean diet can reduce the risk of cardiovascular disease. Olive oil is the hallmark of this dietary pattern. Therefore, this review article has been conducted.

Does olive oil consumption reduce risk of cardiovascular disease?

Study design:
This review article included case-control, prospective cohort studies and a randomised controlled trial investigating the specific association between olive oil consumption and the risk of cardiovascular disease (101,460 participants) or stroke (38,673 participants). The results of all observational studies were adjusted for total energy intake.

Evidence of heterogeneity was apparent for cardiovascular disease, but not for stroke. Both the Egger test (p = 0.06) and the funnel plot suggested small-study effects.

Results and conclusions:
The investigators found in case-controle studies a non-significant reduced risk of 27% [relative risk = 0.73, 95% CI = 0.44-1.21] for cardiovascular disease for a 25g increase in olive oil consumption.

The investigators found in cohort studies a non-significant reduced risk of 4% [relative risk = 0.96, 95% CI = 0.78-1.18] for cardiovascular disease for a 25g increase in olive oil consumption.

The investigators found in cohort studies olive oil consumption significantly reduced risk of stroke with 26% [relative risk = 0.74, 95% CI = 0.60-0.92].

The investigators found random-effects model showed a significant reduced risk of 18% [RR = 0.82, 95% CI = 0.70, 0.96] for combining all cardiovascular events (CHD and stroke).

The investigators concluded available studies support an inverse association of olive oil consumption with stroke and with stroke and cardiovascular disease combined. This finding is in agreement with the recent successful results of the PREDIMED randomised controlled trial.

Original title:
Olive oil consumption and risk of CHD and/or stroke: a meta-analysis of case-control, cohort and intervention studies by Martínez-González MA, Dominguez LJ and Delgado-Rodríguez M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/24775425

Additional information of El Mondo:
Find more studies/information on cardiovascular disease right here.

Objectives:
What is the impact of antioxidants (N-acetylcysteine (NAC), polyunsaturated fatty acids (PUFAs) and vitamins) on incidence of postoperative atrial fibrillation (POAF) and duration of length of hospital stay?

Study design:
This review article included 23 RCTs that reported outcomes of 4278 patients undergoing cardiac surgery.
A total of 10 RCTs with 1,026 patients (513 cases were allocated to the NAC and 513 cases to the control group, with a mean age of 63.2 years and 76.8% being males), 8 RCTs with 2,687 patients (with a mean age of 64.17 years and 77.6% being males), and 5 RCTs with 565 patients (with a mean age of 65.17 years and 73.6% being males) investigated the effect of NAC, PUFA and antioxidant vitamins on POAF, respectively.

There was no publication bias.

Results and conclusions:
The investigators found pooled effects estimates on postoperative atrial fibrillation showed a significant reduction after:
NAC [OR = 0.56, 95% CI = 0.40-0.77, p 0.001, I2 = 15%, p = 0.3];
PUFA [OR = 0.84, 95% CI = 0.71-0.99, p = 0.03] and;
Vitamin C treatment [OR = 0.50, 95% CI = 0.27-0.91, p = 0.02, I2 = 50%].

The investigators found hospital length of stay was not significant reduced after NAC therapy [SMD = 0.082, 95% CI = -0.09 to 0.25, p = 0.3, I2 = 0.0%, p = 0.7], but could be significant decreased with PUFA [SMD = -0.185, 95% CI = -0.35 to -0.018, p = 0.03, I2 = 11%, p = 0.3] and vitamin C [SMD = -0.325, 95% CI = -0.50 to -0.14, p 0.01, I2 = 60.4%, p = 0.056].
Significant because the p-values were less than the p-value of 0.05.

The investigators concluded perioperative antioxidant supplementations with N-acetylcysteine, polyunsaturated fatty acids and vitamin C prevent atrial fibrillation after cardiac surgery. Moreover, polyunsaturated fatty acids and vitamin C are capable to reduce hospital stay, whereas N-acetylcysteine lacks this capacity.

Original title:
Antioxidant supplementations for prevention of atrial fibrillation after cardiac surgery: an updated comprehensive systematic review and meta-analysis of 23 randomized controlled trials by Ali-Hassan-Sayegha S, Mirhosseinia SJ, […], Liakopoulose OJ.

Link:
http://icvts.oxfordjournals.org/content/early/2014/02/19/icvts.ivu020.long

Additional information of El Mondo:
Find more studies on cardiovascular diseases, antioxidants, NAC, PUFA, vitamin C and p-value of 0.05/95% CI right here. 

Objectives:
Does niacine supplementation reduce blood lipids levels in patients with type 2 diabetes mellitus?

Study design:
This review article included randomized controlled trials.

The meta-analysis showed the absence of publication bias and any dose-response relations between niacin and effect size.

There was a significant heterogeneity for the impact of niacin on LDL cholesterol and fasting plasma glucose.

Results and conclusions:
The investigators found niacin supplementation significantly increased HDL cholesterol with 0.27 mmol/L [95% CI = 0.24 to 0.30, p 0.001] in patients with type 2 diabetes mellitus.

The investigators found niacin supplementation significantly reduced LDL cholesterol with 0.250 mmol/L [95% CI = -0.47 to -0.03, p 0.05] in patients with type 2 diabetes mellitus.

The investigators found niacin supplementation significantly reduced triglycerides with 0.39 mmol/L [95% CI = -0.43 to -0.34, p 0.001] in patients with type 2 diabetes mellitus.

The investigators found niacin supplementation significantly increased fasting plasma glucose with 0.085 mmol/L [95% CI = 0.029 to 0.141, p 0.05] compared with controls in patients with long term treatment.

The investigators concluded niacin alone or in combination improves lipid abnormalities in patients with type 2 diabetes mellitus, but requires monitoring of glucose in long term treatment.

Original title:
Effect of niacin on lipids and glucose in patients with type 2 diabetes: A meta-analysis of randomized, controlled clinical trials by Ding Y, Li Y and Wen A.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/25306426

Additional information of El Mondo:
Find more information on niacin (vitamin B3) and diabetes.

Objectives:
Observational studies suggest an association between dietary fiber intake and risk of type 2 diabetes, but the results are inconclusive. Therefore, this review article (meta-analysis) has been conducted.

Does dietary fiber intake reduce risk of type 2 diabetes?

Study design:
This review article included 17 prospective cohort studies of dietary fiber intake and risk of type 2 diabetes involving 19,033 cases and 488,293 participants.

Results and conclusions:
The investigators found total dietary fiber intake significantly reduced risk of type 2 diabetes with 19% [combined RR = 0.81, 95% CI = 0.73-0.90].

The investigators found dietary cereal fiber intake significantly reduced risk of type 2 diabetes with 23% [combined RR = 0.77, 95% CI = 0.69-0.85].

The investigators found dietary fruit fiber intake significantly reduced risk of type 2 diabetes with 6% [combined RR = 0.94, 95% CI = 0.88-0.99].

The investigators found dietary insoluble fiber intake significantly reduced risk of type 2 diabetes with 25% [combined RR = 0.75, 95% CI = 0.63-0.89].

The investigators found a nonlinear relationship of total dietary fiber intake with risk of type 2 diabetes [p for nonlinearity 0.01].

The investigators found dietary fiber intake of 15g per day non-significantly reduced risk of type 2 diabetes with 2% [combined RR = 0.98, 95% CI = 0.90-1.06].

The investigators found dietary fiber intake of 20g per day non-significantly reduced risk of type 2 diabetes with 3% [combined RR = 0.97, 95% CI = 0.87-1.07].

The investigators found dietary fiber intake of 25g per day significantly reduced risk of type 2 diabetes with 11% [combined RR = 0.89, 95% CI = 0.80-0.99].

The investigators found dietary fiber intake of 30g per day significantly reduced risk of type 2 diabetes with 24% [combined RR = 0.76, 95% CI = 0.65-0.88].

The investigators found dietary fiber intake of 35g per day significantly reduced risk of type 2 diabetes with 34% [combined RR = 0.66, 95% CI = 0.53-0.82].

The investigators found that the risk of type 2 diabetes decreased by 6% [combined RR = 0.94, 95% CI = 0.93-0.96] for 2 g/day increment in cereal fiber intake.

The investigators concluded that the intakes of dietary fiber, at least 25g total dietary fiber intake per day reduce risk of type 2 diabetes.

Original title:
Dietary fiber intake and risk of type 2 diabetes: a dose–response analysis of prospective studies by Yao B, Fang H, […], Zhao Y.

Link:
http://link.springer.com/article/10.1007/s10654-013-9876-x

Additional information of El Mondo:
Find more information on fiber and type 2 diabetes right here.