Nutrition and health

Objectives:
Although epidemiological studies have examined the role of chocolate in preventing cardiometabolic disease, the results remain inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does chocolate consumption reduce risk of coronary heart disease (CHD), stroke and diabetes?

Study design:
This review article included 14 prospective cohort studies, with 508,705 participants from six countries and 7,267 coronary heart disease (CHD) cases, 8,197 stroke cases and 13,271 diabetes cases.
The follow-up duration of the studies ranged from 5 to 16 years.
One serving was defined as 30g of chocolate.
The majority of chocolate consumed in the included studies was milk or dark chocolate.

Results and conclusions:
The investigators found in 6 cohort studies for the highest versus lowest intake of chocolate a significant reduced risk of 10% for coronary heart disease [pooled RR = 0.90, 95% CI = 0.82-0.97, I2 = 24.3%, p = 0.25]. Leave-one-out sensitivity analysis had no significant influence on the pooled results.

The investigators found regarding CHD subtype, a significant reduced risk of 14% [RR = 0.86, 95% CI = 0.77-0.96] for myocardial infarction.

The investigators found for studies with follow-up duration of 10 years a significant reduced risk of 28% for coronary heart disease [RR = 0.72, 95% CI = 0.57-0.92].

The investigators found for studies with follow-up duration of ≥10 years a significant reduced risk of 8% for coronary heart disease [RR = 0.92, 95% CI = 0.86-0.99].

The investigators found in dose-response meta-analysis of 5 studies a curvilinear association between chocolate consumption and risk of coronary heart disease [p for nonlinearity = 0.006].

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 6% for coronary heart disease for 1 serving (30g) chocolate per week [RR = 0.94, 95 CI = 0.90-0.99].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 9% for coronary heart disease for 3 servings (90g) chocolate per week [RR = 0.91, 95 CI = 0.85-0.97].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 11% for coronary heart disease for 7 servings (210g) chocolate per week [RR = 0.89, 95 CI = 0.83-0.95].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 12% for coronary heart disease for 10 servings (300g) chocolate per week [RR = 0.88, 95 CI = 0.81-0.95].   

The investigators found in 8 reports from 7 studies for the highest versus lowest level of chocolate consumption a significant reduced risk of 16% for stroke [pooled RR = 0.84, 95% CI = 0.78-0.90, I2 = 0%, p = 0.49]. The pooled risk of total stroke was not obviously modified in the sensitivity analysis by excluding one study at a time
Egger’s test suggested the presence of publication bias [p = 0.008]. However, after introducing the “trim and fill” method to adjust this bias, the overall risk estimate remained significant in favor of chocolate intake [RR = 0.86, 95% CI = 0.79-0.92].

The investigators found with regard to stroke subtypes, a significant reduced risk of 13% [RR = 0.87, 95% CI = 0.78-0.96] for cerebral infarction and a significant reduced risk of 17% [RR = 0.83, 95% CI = 0.71-0.97] for hemorrhagic stroke.

The investigators found in the stratified analysis by gender, a significant reduced risk of 13% of total stroke for male [RR = 0.87, 95% CI = 0.79-0.97] and a significant reduced risk of 16% of total stroke for female [RR = 0.84, 95% CI = 0.74-0.94].

The investigators found a significant reduced risk of 44% for studies with follow-up durations of 10 years [RR = 0.56, 95% CI = 0.37-0.85].

The investigators found a significant reduced risk of 15% for studies with follow-up durations of ≥10 years [RR = 0.85, 95% CI = 0.79-0.91].

The investigators found in 7 reports from 6 studies a nonlinear correlation between chocolate intake and risk of stroke [p for nonlinearity = 0.001].

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 9% for stroke for 1 serving chocolate per week [RR = 0.91, 95% CI = 0.86-0.97].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 13% for stroke for 3 servings chocolate per week [RR = 0.87, 95% CI = 0.81-0.94].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 15% for stroke for 7 servings chocolate per week [RR = 0.85, 95% CI = 0.76-0.93].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 17% for stroke for 10 servings chocolate per week [RR = 0.83, 95% CI = 0.72-0.94].   

The investigators found in 4 studies using “trim and fill” method, for the highest versus lowest intake of chocolate, a non-significant reduced risk of 8% for diabetes [pooled RR = 0.92, 95% CI = 0.78-1.08].

The investigators found in stratified analysis by sex, a significant reduced risk of 21% [RR = 0.79, 95% CI = 0.65-0.96] for men and a non-significant reduced risk of 8% [RR = 0.92, 95% CI = 0.72-1.17] for women.
Similarly, the risks of diabetes were not different between subsets of studies with follow-up durations of below or over 10 years [p for interaction = 0.51].

The investigators found in dose-response meta-analysis of 6 reports, a curvilinear association between chocolate intake and risk of diabetes [p for nonlinearity 0.001].

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 20% for diabetes for 1 serving chocolate per week [RR = 0.80, 95% CI = 0.71-0.91]. Significant means that there is an association with a 95% confidence.

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 24% for diabetes for 3 servings chocolate per week [RR = 0.76, 95% CI = 0.63-0.91]. Significant because RR of 1 was not found in the 95% CI of 0.63 to 0.91. RR of 1 means no risk/association.

The investigators found in dose-response meta-analysis, compared with no intake, a non-significant reduced risk of 17% for diabetes for 7 servings chocolate per week [RR = 0.83, 95% CI = 0.67-1.03]. Non-significant means it cannot be said with a 95% confidence that 7 servings chocolate per week really decreased the risk of diabetes with 17%.

The investigators found in dose-response meta-analysis, compared with no intake, a non-significant reduced risk of 11% for diabetes for 10 servings chocolate per week [RR = 0.89, 95% CI = 0.69-1.16].   

The investigators found in general, the dose-response pattern was J-shaped and the peak reduction in diabetes risk occurred at an intake of 2 servings/week [RR = 0.75, 95% CI = 0.63-0.89], with no protective effects observed when consuming chocolate > 6 servings/week.

The investigators concluded that chocolate consumption confers reduced risks of coronary heart disease, stroke and diabetes. Consuming chocolate in moderation (1-6 servings/week or 30-180g) may be optimal for the prevention of these burdensome diseases. However, additional large prospective studies are required to confirm the observed benefits of chocolate in populations with different characteristics and to establish the optimum frequency of chocolate intake for preventing cardiometabolic disease.

Original title:
Chocolate Consumption and Risk of Coronary Heart Disease, Stroke, and Diabetes: A Meta-Analysis of Prospective Studies by Yuan S, Li X, […], Lu J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537803/

Additional information of El Mondo:
Find more information/studies on chocolate, diabetes and cardiovascular diseases right here.

Objectives:
With only 5-10% of breast cancer cases attributed to genetic inheritance, prevention efforts have focused on modifiable risk factors. Physical activity plays a role in reducing breast cancer risk; however, the interaction between physical activity and other modifiable risk factors, such as obesity, has received little attention. Therefore, this review article (meta-analysis) has been conducted.

What is the relationship between physical activity and breast cancer and how it may be modified by body mass index (BMI)?

Study design:
This review article included 18 cohort and 11 case-control studies.

Results and conclusions:
The investigators found overall, a significant reduction of 15% for breast cancer risk in postmenopausal women with a BMI 25 kg/m² for high versus low levels of physical activity [RR = 0.85, 95% CI = 0.79-0.92]. 

The investigators found overall, a significant reduction of 13% for breast cancer risk in postmenopausal women with a BMI ≥25 kg/m² for high versus low levels of physical activity for women [RR = 0.87, 95% CI = 0.81-0.93]. 

The investigators found overall, a non-significant reduction of 7% for breast cancer risk in postmenopausal women with a BMI ≥30 kg/m² for high versus low levels of physical activity for women [RR = 0.93, 95% CI = 0.76-1.13]. 

The investigators found, however, physical activity was not associated with a significant reduction in risk of breast cancer in premenopausal women in any BMI group.

The investigators concluded high levels of physical activity reduce risk of breast cancer in postmenopausal women with a BMI until 30. Since the included studies used diverse methods for assessment of physical activity and categories of BMI, results should be interpreted with caution and additional work is needed.

Original title:
Does obesity modify the relationship between physical activity and breast cancer risk? by Neil-Sztramko SE, Boyle T, […], Campbell KL.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28803384

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

Objectives:
In the 2007 World Cancer Research Fund/American Institute for Cancer Research Second Expert Report, the expert panel judged that there was strong evidence that alcoholic drinks and body fatness increased esophageal cancer risk, whereas fruits and vegetables probably decreased its risk. The judgments were mainly based on case-control studies. As part of the Continuous Update Project (CUP), this review article (meta-analysis) has been conducted.

What is the relationship between nutrition and esophageal cancer risk?

Study design:
This review article included a total of 57 cohort studies, used in previous 13 meta-analyses.

Results and conclusions:
The investigators found a significant reduced risk of 11% for esophageal adenocarcinoma for every increment of 100g/day vegetable intake [RR = 0.89, 95% CI = 0.80-0.99, n = 3].

The investigators found a significant increased risk of 47% for esophageal adenocarcinoma for every 5 unit increment in BMI [RR = 1.47, 95% CI = 1.34-1.61, n = 9].

The investigators found a significant reduced risk of 16% for esophageal squamous cell carcinoma for every increment of 100g/day fruit intake [RR = 0.84, 95% CI = 0.75-0.94, n = 3].

The investigators found a significant reduced risk of 36% for esophageal squamous cell carcinoma for every 5 unit increment in BMI [RR = 0.64, 95% CI = 0.56-0.73, n = 8].

The investigators found a significant increased risk of 59% for esophageal squamous cell carcinoma for every increment of 50g/day processed meat intake [RR = 1.59, 95% CI = 1.11-2.28, n = 3].

The investigators found a significant increased risk of 37% for esophageal squamous cell carcinoma for every increment of 100g/day processed and red meat intake [RR = 1.37, 95% CI = 1.04-1.82, n = 3].

The investigators found a significant increased risk of 25% for esophageal squamous cell carcinoma for every increment of 10g/day alcohol intake [RR = 1.25, 95% CI = 1.12-1.41, n = 6].

The investigators concluded evidence from cohort studies shows a protective role of vegetables and body weight control in esophageal adenocarcinomas development. For squamous cell carcinomas, higher intakes of red and processed meats and alcohol increase the risk, whereas fruits intake has a protective role.

Original title:
An update of the WCRF/AICR systematic literature review and meta-analysis on dietary and anthropometric factors and esophageal cancer risk by Vingeliene S, Chan DSM, […], Norat T.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28666313

Additional information of El Mondo:
Find more information/studies on vegetable, fruit, alcohol and meat consumption, significant/cohort/95% CI and cancer right here.
 

Objectives:
The relationship between intake of fish and n-3 fatty acids and endometrial cancer risk has not been consistent across epidemiological studies. Therefore, this review article (meta-analysis) has been conducted.

Do fish consumption and dietary EPA and DHA intake reduce endometrial cancer risk?

Study design:
This review article included 4 prospective cohort studies, 1 case-cohort study and 11 case-control studies (including 8 population-based case-control studies and 3 hospital-based case-control studies).
The prospective cohort studies had a mean follow-up of 6.5 to 9.1 years.
The highest category of fish ranged from >1-2 servings/week to >15.4 servings/week,
The highest category of DHA ranged from 143 to 227 mg/d.
The highest category of EPA ranged from 74.7 to 127 mg/d.

When fish intake was reported in unit of g/d, it was converted to serving/week by assuming 1 serving = 100g.
Overall, all 16 studies were classified as high-quality studies.
There was no publication bias.

Results and conclusions:
The investigators found a non-significant association between the highest vs. lowest category of fish consumption and endometrial cancer risk [RR = 1.04, 95% CI = 0.84-1.30, I2 = 80.4%].
According to the subgroup analyses, the null association persisted in strata according to study design, location, type of controls, number of cases, publication year and adjustments of energy intake, reproductive factors and smoking.

The investigators found in subgroup analyses for every one additional serving/week of fish intake, a significant reduced risk of 10% for endometrial cancer in studies conducted in Europe [RR = 0.90, 95% CI = 0.84-0.97]. Significant means that there is an association with a 95% confidence.

The investigators found in subgroup analyses for every one additional serving/week of fish intake, a significant increased risk of 15% for endometrial cancer in studies conducted in Asia [RR = 1.15, 95% CI = 1.10-1.21]. Significant because RR of 1 was not found in the 95% CI of 1.10 to 1.21. RR of 1 means no risk/association.

The investigators found in studies adjusting for smoking for every one additional serving/week of fish intake, a significant reduced risk of 5% for endometrial cancer [RR = 0.95, 95% CI = 0.91-1.00].

The investigators found in studies without an adjustment of smoking for every one additional serving/week of fish intake, a significant increased risk of 14% for endometrial cancer [RR = 1.14, 95% CI = 1.09-1.19].

The investigators found a non-significant inverse association between the highest category of DHA intake and endometrial cancer risk [RR = 0.85, 95% CI = 0.64-1.11, I2 = 59.6%]. However, the dose-response analysis suggested a significant non-linear relationship between DHA intake and endometrial cancer risk [p = 0.04 and p for heterogeneity = 0.39], with a decreased risk being detected for an intake of DHA no more than 175 mg/d.

The investigators concluded that there is a significant inverse association between every one additional serving/week of fish intake and endometrial cancer risk in studies conducted in Europe and studies adjusted for smoking. Furthermore, there is a significant non-linear relationship between DHA intake and risk of endometrial cancer, with a decreased risk being detected for an intake of DHA no more than 175 mg/d. Further well-designed studies are warranted to better characterize the relationship between fish, n-3 PUFA and endometrial cancer development.

Original title:
Dietary n-3 polyunsaturated fatty acids, fish consumption, and endometrial cancer risk: a meta-analysis of epidemiological studies by Hou R, Yao SS, […], Jiang L.

Link:
http://www.impactjournals.com/oncotarget/index.php?journal=oncotarget&page=article&op=view&path[]=18295&path[]=58664

Additional information of El Mondo:
Find more information/studies on fish consumption, significant/cohort/95% CI and cancer right here.
These fish contain 175 mg DHA.
 

Objectives:
Although several epidemiological studies have investigated the association between dietary calcium intake and the risk of esophageal cancer, the results are inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does dietary calcium intake reduce risk of esophageal cancer?

Study design:
This review article included 3 cohort studies and 14 case-control studies, including 3,396 cases (subjects with esophageal cancer) and 346,815 controls (subjects without esophageal cancer).

Egger’s test showed no evidence of significant publication bias.

The sample size was large enough to evaluate the effect of calcium intake on esophageal cancer.

A dose-response effect analysis could not be performed due to the incomplete data of dietary calcium intake.

The average of highest dietary calcium intake in Asian populations was 621 mg/day.

Results and conclusions:
The investigators found for highest vs. lowest dietary calcium intake a significant reduced risk of 20% for esophageal cancer [pooled OR = 0.80, 95% CI = 0.71-0.91, I2 = 33.6%].
This significant reduced risk was also found in studies conducted in Asia [OR = 0.67, 95% CI = 0.52-0.86, I2 = 0.0%], studies published after 2000 [OR = 0.64, 95% CI = 0.53-0.77, I2 = 0.0%), studies adjusted for dietary energy intake [OR = 0.83, 95% CI = 0.70-0.98, I2 = 3.6%], studies of esophageal squamous cell carcinoma [OR = 0.76, 95% CI = 0.60-0.96, I2 = 28.3%], cohort studies [OR = 0.67, 95% CI = 0.54-0.84, I2 = 23.6%] and studies with high quality score [OR = 0.76, 95% CI = 0.66-0.87, I2 = 12.7%].

The investigators found in sensitivity analysis (conducted by leaving one study out in turn and pooling the ORs of the remaining studies) the summary ORs did not substantially change, which indicated that the results were statistically robust.

The investigators concluded that a higher intake (621 mg/day) of dietary calcium has protective effect against esophageal cancer - especially esophageal squamous cell cancer - in Asian populations. To further solidify the association of dietary calcium intake with the risk of esophageal cancer, well-designed studies - especially prospective cohort studies with validated FFQ and adjusted for dietary energy intake - should be conducted.

Original title:
Protective Effect of Dietary Calcium Intake on Esophageal Cancer Risk: A Meta-Analysis of Observational Studies by Li Q, Cui, L, […], Wang L.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5452240/

Additional information of El Mondo:
Find more information/studies on calcium, significant/cohort/95% CI and cancer right here.
 

Objectives:
The clinical benefits of perioperative antioxidant vitamin therapy in cardiac patients remain controversial. Therefore, this review article (meta-analysis) has been conducted.

Do patients undergoing cardiac surgery benefit from perioperative antioxidant vitamin therapy?

Study design:
This review article included 12 RCTs with 1584 cardiac patients.

Results and conclusions:
The investigators found compared with placebo or no antioxidant vitamin therapy that administration of antioxidant vitamin therapy resulted in a significant reduction:
-in postoperative atrial fibrillation (POAF) [RR = 0.55, 95% CI = 0.42 to 0.73, p  0.0001];
-duration of hospital stay [MD = -0.68, 95% CI = -0.98 to -0.39, p  0.00001];
-intensive care unit length of stay [MD = -0.21, 95% CI = -0.30 to -0.12, p  0.00001] and;      
-intubation time [MD = -2.41, 95% CI = -3.83 to -0.98, p = 0.001].

The investigators also found a trend towards a decrease in postoperative complications [RR = 0.72, 95% CI = 0.48-1.08, p = 0.11] and duration of postoperative atrial fibrillation [MD = -1.950, 95% CI = -3.28 to 0.29, p = 0.10].

The investigators concluded that perioperative antioxidant vitamin therapy in patients undergoing cardiac surgery reduces the incidence of postoperative atrial fibrillation, duration of hospital stay, intensive care unit length of stay and intubation time.

Original title:
The clinical benefits of perioperative antioxidant vitamin therapy in patients undergoing cardiac surgery: a meta-analysis by Geng J, Qian J, […], Shen Z.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28645181

Additional information of El Mondo:
Find more information/studies on antioxidant and cardiovascular diseases right here.

Objectives:
Studies implicate choline and betaine metabolite trimethylamine N-oxide (TMAO) in cardiovascular disease (CVD). Therefore, this review article (meta-analysis) has been conducted.

Is there an association between choline and betaine dietary intake and cardiovascular disease?

Study design:
This review article included a total of 6 prospective cohort studies comprising 18,076 incident cardiovascular disease events, 5,343 cardiovascular disease deaths among 184,010 participants.

There was no evidence for heterogeneity among studies.
Only 2 studies provided data on phosphatidylcholine and cardiovascular disease mortality.

Results and conclusions:
The investigators found in random effects meta-analysis, incident cardiovascular disease was not associated with choline [RR = 1.00, 95% CI = 0.98-1.02] or betaine [RR = 0.99, 95% CI = 0.98-1.01] dietary intake.
Results did not vary by study outcome (incident coronary heart disease, stroke, total cardiovascular disease).

The investigators found random effects meta-analysis did not support an association between choline and cardiovascular disease mortality [RR = 1.09, 95% CI = 0.89-1.35], but one study supported a positive association and there was significant heterogeneity [I2 = 84%, p 0.001].

The investigators concluded that there is no association between dietary choline/betaine intake with incident cardiovascular disease, but further research into choline and cardiovascular disease mortality are needed.

Original title:
Dietary Choline and Betaine and Risk of CVD: A Systematic Review and Meta-Analysis of Prospective Studies by Meyer KA and Shea JW.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28686188

Additional information of El Mondo:
Find more information/studies on choline and cardiovascular diseases right here.

Objectives:
Controversy exists on the association between alcohol consumption and risk of heart failure (HF). Therefore, this review article (meta-analysis) has been conducted.

Is there an association between alcohol consumption and risk of heart failure?

Study design:
This review article included a total of 13 prospective cohort studies, with 13,738 heart failure cases among 355,804 participants.

Results and conclusions:
The investigators found light alcohol drinking (0.1-7 drinks/week) significantly reduced risk of heart failure with 14% [RR = 0.86, 95% CI = 0.81-0.90]. However, there was no statistically significant association between moderate (7.1-14 drinks/week), high (14.1-28 drinks/week), or heavy (>28 drinks/week) alcohol consumption and heart failure risk.

The investigators found former drinking significantly increased risk of heart failure with 22% [RR = 1.22, 95% CI = 1.11-1.33] compared with never or occasional drinking.

The investigators concluded that light alcohol drinking (0.1-7 drinks/week) is associated with a lower risk of heart failure, while former drinking is associated with a higher risk of heart failure.

Original title:
Alcohol consumption and risk of heart failure: Meta-analysis of 13 prospective studies by Susanna C. Larsson, […], Alicja Wolk

Link:
http://www.sciencedirect.com/science/article/pii/S0261561417301681

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

Objectives:
Low glycaemic index (GI) diets are beneficial in the management of hyperglycemia. Cardiovascular diseases are the major cause of mortality in diabetes therefore it is important to understand the effects of GI on blood lipids. Therefore, this review article has been conducted.

Does a low GI diet lower the cholesterol levels?

Study design:
This review article included 28 RCTs comparing low with high GI diets over at least 4 weeks. These 28 RCTs contained 1272 participants with studies ranged from 6 to 155 participants, one was powered on blood lipids and 3 had adequate allocation concealment.

Results and conclusions:
The investigators found that compared to high GI diet low GI diet significantly reduced total cholesterol by 0.13 mmol/L [95% CI = -0.22 to -0.04, p = 0.004, 27 trials, 1441 participants]. Significantly means, it can be said with 95% confidence that low GI diet really lowered the total cholesterol levels with 0.13 mmol/L.

The investigators found that compared to high GI diet low GI diet significantly reduced LDL-cholesterol by 0.16 mmol/L [95% CI = -0.24 to -0.08, p 0.0001, 23 studies, 1281 participants]. Significantly, because the p-value was less than 0.05.

The investigators found subgroup analyses suggested that reductions in LDL-cholesterol were greatest in studies of shortest duration and greatest magnitude of GI reduction. Furthermore, lipid improvements appeared greatest and most reliable when the low GI intervention was accompanied by an increase in dietary fiber.

The investigators found sensitivity analyses, removing studies without adequate allocation concealment, lost statistical significance but retained suggested mean falls of 0.10 mmol/L in both.

The investigators found no effects on HDL-cholesterol [MD = -0.03 mmol/L, 95% CI = -0.06 to 0.00, I2 = 0%], or triglycerides [MD was 0.01 mmol/L, 95% CI = -0.06 to 0.08, I2 = 0%].

The researchers concluded that low GI diets reduce total and LDL-cholesterol (bad cholesterol) but had no effect on HDL-cholesterol (good cholesterol) or triglycerides.

Original title:
Low glycemic index diets and blood lipids: A systematic review and meta-analysis of randomized controlled trials by Goff LM, Cowland DE, [...], Frost GS.

Link:
http://www.sciencedirect.com/science/article/pii/S0939475312001524

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

High LDL-cholesterol levels and high triglyceride levels increase the risk of getting cardiovascular diseases whereas high HDL-cholesterol levels decrease the risk of getting cardiovascular diseases.

A low GI diet is a diet with a GI value of 55 or lower.

Objectives:
Recent evidence has suggested that flavonoid and lignan intake may be associated with decreased risk of chronic and degenerative diseases. Therefore, this review article (meta-analysis) has been conducted.

Does dietary flavonoid intake reduce risk of all-cause and cardiovascular disease mortality?

Study design:
This review article included 22 prospective cohort studies.

Results and conclusions:
The investigators found when compared with lower consumption, high consumption of total flavonoids was associated with a significant decreased risk of 26% for all-cause mortality [risk ratio = 0.74, 95% CI = 0.55-0.99].

The investigators found a 100-mg/day increment in dietary total flavonoids intake led to a (linear) decreased risk of 6% and 4% of all-cause and cardiovascular disease mortality, respectively.

The investigators found among flavonoid classes, significant results were obtained for intakes of flavonols, flavones, flavanones, anthocyanidins and proanthocyanidins.

The investigators found limited evidence was available on lignans intake and all-cause mortality.

The investigators concluded that higher dietary flavonoids intakes - at least 100-mg/day of flavonols, flavones, flavanones, anthocyanidins or proanthocyanidins - are associated with decreased risk of all-cause and cardiovascular disease mortality.

Original title:
Dietary Flavonoid and Lignan Intake and Mortality in Prospective Cohort Studies: Systematic Review and Dose-Response Meta-Analysis by Grosso G, Micek A, […], Giovannucci EL.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28472215

Additional information of El Mondo:
Find more information/studies on flavonoids and cardiovascular diseases 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:
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Objectives:
The association between elevated serum phosphorus concentration and cardiovascular or all-cause mortality yielded conflicting results. Therefore, this review article (meta-analysis) has been conducted.

Does an elevated serum phosphorus concentration increase cardiovascular and all-cause mortality in the general population?

Study design:
This review article included 6 prospective cohort studies involving 120,269 subjects.

Results and conclusions:
The investigators found when compared the highest with the reference concentration of serum phosphorus, a significant increased risk of 36% for cardiovascular mortality [pooled RR = 1.36, 95% CI = 1.07-1.72]. Significant because RR of 1 was not found in the 95% CI of 1.07 to 1.72. RR of 1 means no risk/association.

The investigators found when compared the highest with the reference concentration of serum phosphorus, a significant increased risk of 33% for all-cause mortality [pooled RR = 1.33, 95% CI = 1.15-1.58]. Significant means that there is an association with a 95% confidence.

The investigators found stratified analyses revealed that elevated serum phosphorus significantly increased all-cause mortality risk with 33% among men [RR 1.33, 95% CI = 1.11-1.60], but not in women [RR = 1.09, 95% CI = 0.89-1.33].

The investigators concluded elevated serum phosphorus concentration is independently associated with excessive risk of cardiovascular and all-cause mortality in the general population without chronic kidney disease. Serum phosphorus on all-cause mortality risk appears to be pronounced in men but exhibits no clear effect on women. However, gender difference of elevated serum phosphorus on mortality risk should be verified by more prospective cohort studies.

Original title:
Serum phosphorus, cardiovascular and all-cause mortality in the general population: A meta-analysis by Bai W, Li J and Liu J.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/27475981

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Objectives:
Increased dietary potassium intake is thought to be associated with low blood pressure (BP). Whether potassium supplementation may be used as an antihypertensive agent is a question that should be answered. Therefore, this review article (meta-analysis) has been conducted.

Does potassium supplementation reduce blood pressure among patients with essential hypertension (SBP ≥140 mmHg and DBP ≥90 mmHg)?

Study design:
This review article included 23 trials (9 parallel and 14 crossover randomized placebo-controlled clinical trials with a minimum of 4 weeks of therapy to ensure that the intervention had sufficient time to produce an effect) involving 1,213 patients with essential hypertension (SBP ≥140 mmHg and DBP ≥90 mmHg).

The result of meta-regression revealed that the association between potassium dosage, follow-up period and mean age were not statistically significant; therefore they did not play an important role in the heterogeneity across studies.

There was no publication bias.

Results and conclusions:
The investigators found that potassium supplementation significantly reduced systolic blood pressure (SBP) of patients with essential hypertension with 4.25 mmHg [95% CI = -5.96 to -2.53, I2 = 41%].

The investigators found that potassium supplementation significantly reduced diastolic blood pressure (DBP) of patients with essential hypertension with 2.53 mmHg [95% CI = -4.05 to -1.02, I2 = 65%].

The investigators found in 8 RCTs when compared to baseline, the mean changes in systolic blood of patients with essential hypertension was -8.89 mmHg [95% CI = -13.67 to -4.11] significantly higher in the intervention group (group taking potassium supplements) than the control group. 

The investigators found in 8 RCTs when compared to baseline, the mean changes in diastolic blood pressure of patients with essential hypertension was -6.42 mmHg [95% CI = -10.99 to -1.84] significantly higher in the intervention group (group taking potassium supplements) than the control group. 

The investigators found in subgroup analysis that the mean difference in systolic blood of patients with essential hypertension was -2.64 mmHg [95% CI = -5.25 to -0.03] in America, -4.56 mmHg [95% CI = -6.51 to -2.62) in Europe and -5.21 mmHg [95% CI = -9.63 to -0.79] in Asia.

The investigators found a dose-response relationship between potassium intake and reduction in systolic and diastolic blood pressure (low-dose (50 mmol/day), moderate-dose (50-99 mmol/day) and high-dose (≥100 mmol/day)).

The investigators concluded that potassium supplementation for at least 4 weeks reduces blood pressure of patients with essential hypertension and therefore, can be recommended as an adjuvant antihypertensive agent for patients with essential hypertension (SBP ≥140 mmHg and DBP ≥90 mmHg).

Original title:
Oral potassium supplementation for management of essential hypertension: A meta-analysis of randomized controlled trials by Poorolajal J, Zeraati F, […], Maleki A.

Link:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0174967

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Objectives:
There have been inconsistent results about the association between consumption of fruits and vegetables and renal cell carcinoma (RCC) risk. Therefore, this review article (meta-analysis) has been conducted.

Does consumption of fruits and vegetables reduce renal cell carcinoma risk?

Study design:
This review article included 19 observational studies (4 cohort, 1 pooled and 14 case-control studies), involving 10,215 subjects with renal cell carcinoma.

Only 4 studies adjusted for all the 3 main risk factors for renal cell carcinoma (16 studies adjusted for tobacco smoking, 15 for BMI and 4 for hypertension).
The majority of included studies (16/19) were of high quality (NOS score ≥ 7).

Results and conclusions:
The investigators found for highest vs. lowest vegetables intake a significant reduced risk of 27% for renal cell carcinoma [SRR = 0.73, 95% CI = 0.63-0.85, I2 = 53.5%, p = 0.004]. Significant means that there is an association with a 95% confidence.

The investigators found for highest vs. lowest vegetables intake a non-significant reduced risk of 13% for renal cell carcinoma in cohort studies [SRR = 0.87, 95% CI = 0.72-1.06].

The investigators found in dose-response analysis a significant reduced risk of 10% for renal cell carcinoma per 1 serving/day vegetables intake [SRR = 0.90, 95% CI = 0.84-0.96, I2 = 69.0%, p 0.001].

The investigators found a non-linear association between vegetable intake and renal cell carcinoma risk [p = 0.001 for non-linearity] with a significant reduction in renal cell carcinoma risk when increasing the intake up to about 3 servings/d intake of vegetables. Higher intake was associated with a further, but more modest decrease in risk.

The investigators found for highest vs. lowest fruits intake a significant reduced risk of 14% for renal cell carcinoma [SRR = 0.86, 95% CI = 0.75-0.98, I2 = 47.4%, p = 0.012].

The investigators found for highest vs. lowest fruits intake a significant reduced risk of 28% for renal cell carcinoma among European [SRR = 0.72, 95% CI = 0.56-0.93]. However, this reduced risk was not significant among North Americans [SRR = 0.97, 95% CI = 0.81-1.16].

The investigators found for highest vs. lowest fruits intake a significant reduced risk of 22% for renal cell carcinoma in population-based case-control studies [SRR = 0.78, 95% CI = 0.63-0.97]. However, this reduced risk was not significant in cohort studies [SRR = 0.90, 95% CI = 0.73-1.10] and in hospital-based case-control studies [SRR = 0.96, 95% CI = 0.69-1.33].

The investigators found in dose-response analysis no associaition between 1 serving/day increment of fruits and renal cell carcinoma risk [SRR = 0.97, 95% CI = 0.93-1.01, I2 = 57.8%, p = 0.011].

The investigators found a linear association between fruits intake and renal cell carcinoma risk [p = 0.221 for non-linearity].

The investigators concluded that consumption of 1-3 servings/d vegetables and high fruits may lower the risk of renal cell carcinoma development. May lower, because significant associations for vegetables and fruits were only observed in case-control, but not in cohort studies. Because of the measurement errors of exposure assessment, the high heterogeneity across studies and unmeasured confounding factors, further investigation with good designs are needed.

Original title:
Consumption of fruits and vegetables and risk of renal cell carcinoma: a meta-analysis of observational studies by Zhang S, Jia Z, [...], Yang J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5438616/

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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

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Objectives:
Does allium vegetable consumption reduce gastric cancer risk?

Study design:
This review article included 22 case-control and 4 cohort studies with more than 10,000 cases.

Results and conclusions:
The investigators found in 10 case-control and 4 cohort studies for the highest versus lowest allium vegetables intake category a significant reduced risk of 22% for gastric cancer [OR = 0.78, 95% CI = 0.67-0.91].

The investigators found in 12 case-control studies for the highest versus lowest garlic intake category a significant reduced risk of 40% for gastric cancer [OR = 0.60, 95% CI = 0.47-0.76].

The investigators found in 13 case-control studies for the highest versus lowest onion intake category a significant reduced risk of 45% for gastric cancer [OR = 0.55, 95% CI = 0.41-0.73].

The investigators found in 4 cohort studies for the highest versus lowest allium vegetables intake category a non-significant increased risk of 2% for gastric cancer [RR = 1.02, 95% CI = 0.88-1.18]. Non-significant means no association with 95% confidence.

The investigators concluded high allium vegetable consumption, like garlic and onion is likely to reduce gastric cancer risk. Likely because this evidence is derived mainly from case-control studies. Therefore, further data from large cohorts are desirable for conclusive confirmation.

Original title:
Allium vegetable intake and gastric cancer: a case-control study and meta-analysis by Turati F, Pelucchi C, […], Galeone C.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/25215621

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Objectives:
An increased intake of magnesium might lower blood pressure (BP), yet evidence from clinical trials is inconsistent, perhaps as a result of small sample size or heterogeneity in study design. Therefore, this review article (meta-analysis) has been conducted.

Are there dose-dependent effects of magnesium supplementation on blood pressure?

Study design:
This review article included 20 RCTs included 14 of hypertensive and 6 of normotensive persons totaling 1220 participants.
The doses of magnesium ranged from 10 to 40 mmol/day (median: 15.4 mmol/day or 370 mg per day).

Results and conclusions:
The investigators found magnesium supplementation resulted in only a small overall non-significant reduction in blood pressure. The pooled net estimates of blood pressure change were -0.6 mmHg [95% CI = -2.2 to 1.0] for systolic blood pressure and -0.8 mmHg [95% CI = -1.9 to 0.4] for diastolic blood pressure.

However, the investigators found an apparent dose-dependent effect of magnesium, with significant reductions of 4.3 mmHg systolic blood pressure [95% CI = 6.3 to 2.2, p 0.001) and non-significant reductions of 2.3 mmHg diastolic blood pressure [95% CI = 4.9 to 0.0, p = 0.09) for each 10 mmol/day (240 mg/day) increase in magnesium dose.

The investigators concluded there is a dose-dependent blood pressure reductions, especially systolic blood pressure from magnesium supplementation. However, adequately powered trials with sufficiently high doses of magnesium supplements need to be performed to confirm this relationship.

Original title:
The effect of magnesium supplementation on blood pressure: a meta-analysis of randomized clinical trials by Jeea SH, Miller ER, [...], Klagb MJ.

Link:
http://www.sciencedirect.com/science/article/pii/S0895706102029643

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Objectives:
Previous studies regarding the relationship between legume intake and risk of prostate cancer have reported inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Does legume intake reduce prostate cancer risk?

Study design:
This review article included 8 prospective cohort studies reporting 281,034 individuals and 10,234 incident prostate cancer cases.

Results and conclusions:
The investigators found when comparing high consumption of legumes with low consumption a significant reduced risk of 15% [RR = 0.85, 95% CI = 0.75-0.96, p = 0.010, I2 = 45.8%] for prostate cancer.

The investigators found dose-response meta-analysis indicated that the risk of prostate cancer reduced by 3.7% [95% CI = 1.5%-5.8%] for each 20 grams per day increment of legume intake.

The investigators concluded that a high dietary intake of legumes, at least 20 grams per day is associated with a low incidence of prostate cancer.

Original title:
Legume intake and risk of prostate cancer: a meta-analysis of prospective cohort studies by Li J and Mao QQ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28423366

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Objectives:
Thyroid cancer (TC) is the most common malignancy of the endocrine system. The relationship between iodine intake and thyroid cancer risk is controversial always. Therefore, this review article (meta-analysis) has been conducted.

Does dietary intake of iodine reduce thyroid cancer risk?

Study design:
This review article included 8 case-control studies with in total 2213 subjects with thyroid cancer and 2761 subjects without thyroid cancer.

With regard to publication bias, owing to the limited number (below 10) of studies included in the saltwater fish, shellfish and iodine intake analyses, publication bias was not assessed.

Results and conclusions:
The investigators found adequate or excess iodine dietary intake (>300 μg/d) significantly decreased the risk of thyroid cancer with 26% [OR = 0.74, 95% CI = 0.60-0.92].

The investigators found high consumption of saltwater fish (≥3 times/wk or ≥12 times/mo) significantly decreased the risk of thyroid cancer with 28% [OR = 0.72, 95% CI = 0.55-0.95, p = 0.02].

The investigators found high consumption of shellfish (≥3 times/wk or ≥12 times/mo) significantly decreased the risk of thyroid cancer with 30% [OR = 0.70, 95% CI = 0.52-0.96, p = 0.03].

The investigators concluded a higher intake of dietary iodine (>300 μg/d) may decrease the risk of thyroid cancer in populations mainly based in coastal cities or on islands. May decrease, because this review article did not include cohort  studies.

Original title:
The relationship between iodine intake and the risk of thyroid cancer: A meta-analysis by Cao LZ, Peng XD, [...], Li S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5440127/

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Objectives:
The findings of prospective cohort studies are inconsistent regarding the association between dietary magnesium intake and serum magnesium concentration and the risk of hypertension. Therefore, this review article (meta-analysis) has been conducted.

Do dietary magnesium intake and serum magnesium concentrations reduce risk of hypertension?

Study design:
This review article included 10 cohort studies, including 20,119 cases of hypertension and 180,566 participants.

The range of dietary magnesium intake was 96-25 mg/day and serum magnesium levels were 0.66-0.95 mmol/L.

The funnel plot showed reasonable symmetry, with no evidence of publication bias (Egger’s test p = 0.95 and Begg’s test p = 0.71).

Results and conclusions:
The investigators found when comparing the highest to the lowest category of dietary magnesium consumption, a significant reduced risk of 8% for hypertension [pooled RR = 0.92, 95% CI = 0.86-0.98].

The investigators found for every 100 mg/day increment in dietary magnesium intake a significant reduced risk of 5% for hypertension [pooled RR = 0.95, 95% CI = 0.90-1.00, I2 = 39.3%, p = 0.13].
The reduced hypertension risk associated with 100 mg/day was tended to be observed when the duration of follow-up was more than 8 years and when the results were adjusted separately for calcium, sodium, fiber, cholesterol, saturated fat intake or smoking.

The investigators found the dose-response meta-analysis suggested a marginal linear relationship between dietary magnesium intake and hypertension risk [p for linearity = 0.057].

The investigators found no association between serum magnesium concentrations and reduced risk of hypertension [pooled RR = 0.91, 95% CI = 0.80-1.02, p = 0.10, I2 = 0%, p = 0.48].

The investigators concluded that increased dietary magnesium intake is associated with lower risk of hypertension in a linear dose-response pattern. However, there is no association between serum magnesium concentration and risk of hypertension.

Original title:
Dose-response relationship between dietary magnesium intake, serum magnesium concentration and risk of hypertension: a systematic review and meta-analysis of prospective cohort studies by Han H, Fang X, […], Cao Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5420140/

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Objectives:
Prostate cancer (PCa) is the fifth leading cause of cancer-related deaths worldwide. Many epidemiological studies have investigated the association between prostate cancer and lycopene, however, results have been inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does lycopene reduce prostate cancer risk?

Study design:
This review article included 42 studies including 43,851 cases of prostate cancer reported from 692,012 participants.

Results and conclusions:
The investigators found dietary intake of lycopene was significantly associated with a reduced prostate cancer risk of 12% [RR = 0.88, 95% CI = 0.78-0.98, p = 0.017].

The investigators found circulating concentrations of lycopene were significantly associated with a reduced prostate cancer risk of 12% [RR = 0.88, 95% CI = 0.79-0.98, p = 0.019].

The investigators found sensitivity analyses within the dose-response analysis further revealed a significant linear dose-response for dietary lycopene and prostate cancer risk such that prostate cancer decreased by 1% for every additional 2 mg of lycopene consumed [p = 0.026].

The investigators found prostate cancer risk decreased by 3.5 to 3.6% for each additional 10 μg/dL of circulating lycopene in the linear and nonlinear models, respectively [p-linear = 0.004, p-non linear = 0.006].

The investigators found no association between lycopene and advanced prostate cancer. However, there was a trend for protection against prostate cancer aggressiveness [RR = 0.74, 95% CI = 0.55-1.00, p = 0.052].

The investigators concluded that higher dietary and circulating lycopene concentrations reduce prostate cancer risk. This was accompanied by dose-response relationships for dietary and circulating lycopene. Further studies are required to determine the mechanisms underlying these associations.

Original title:
Increased dietary and circulating lycopene are associated with reduced prostate cancer risk: a systematic review and meta-analysis by Rowles JL, Ranard KM, […], Erdman JW Jr.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28440323

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Objectives:
There are conflicting reports on the correlation between manganese (Mn) levels and breast cancer. Therefore, this review article (meta-analysis) has been conducted.

Does manganese deficiency increase risk of breast cancer?

Study design:
This review article included 11 case-control studies involving 1302 subjects.

There was no evidence of publication bias. Sensitivity analysis showed that excluding any one study from the pooled analysis did not vary the results substantially.

Results and conclusions:
The investigators found the random-effects meta-analysis results indicated that subjects with breast cancer had lower manganese levels in serum and hair than healthy controls [SMD = -1.51, 95% CI = -2.47 to -0.56, I2 = 97.8%, p 0.001].

The investigators found in subgroup analysis that subjects with breast cancer had lower manganese levels than healthy controls in China [SMD = -1.32, 95% CI = -2.33 to -0.32] and Korea [SMD = -4.08, 95% CI = -4.63 to -3.54], but not in Turkey [SMD = -0.96, 95% CI = -3.19 to 1.27].

The investigators found in subgroup analysis that the differences of manganese levels between patients with breast cancer and healthy controls were similar in different sample specimens:
serum [SMD = -1.24, 95% CI = -2.31 to -0.16];
hair [SMD = -1.99, 95% CI = -3.91 to -0.06] and;
different types of manganese measurement:

ICP-AAS [SMD = -1.14, 95% CI = -2.24 to -0.04];
GFAAS [SMD = -1.94, 95% CI = -2.38 to -1.49];
ICP-AES [SMD = -3.77, 95% CI = -4.70 to -2.85]. These findings can well explain that  the between-study variability was the main source of heterogeneity.

The investigators concluded there is an association between deficient manganese concentration and breast cancer. However, the subgroup analysis found that there was contradiction regarding races and geography, like China and Turkey. Thus this finding needs further confirmation by trans-regional multicenter, long-term observation in a cohort design to obtain better understanding of causal relationships between manganese levels and breast cancer, through measuring manganese at baseline to investigate whether the highest manganese category versus lowest was associated with breast cancer risk.

Original title:
The association between deficient manganese levels and breast cancer: a meta-analysis by Shen F, Cai WS, [...],Xu B.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4443096/

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Objectives:
Heart failure (HF) remains a major health problem affecting 5.7 million adults in USA. Data on the association of egg consumption with incident heart failure have been inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does egg consumption increase incident heart failure in the general population?

Study design:
This review article included 4 prospective cohort studies with a total of 105,999 subjects and 5,059 cases of new onset heart failure.

There was no evidence of publication bias on funnel plot analysis as supported by the Egger’s test (p = 0.68).

Results and conclusions:
The investigators found when comparing the highest (≥1/day) to the lowest category of egg consumption, a significant increased risk of 25% [pooled RR = 1.25, 95% CI = 1.12-1.39, p = 0.00, I2 = %] for heart failure.

The investigators found that sensitivity analysis (stratification by excluding studies with men/women, 20 years of follow-up duration, US/Non-US studies) did not alter the main conclusion.

The investigators concluded that at least 1 egg per day increases heart failure risk in the general population. Further studies are warranted to explore the underlying biological mechanisms.

Original title:
Egg Consumption and Incidence of Heart Failure: A Meta-Analysis of Prospective Cohort Studies by Khawaja O, Singh H, […], Djoussé L.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5367008/

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Objectives:
Quantification of the association between the intake of fruit and vegetables and risk of esophageal squamous cell carcinoma (ESCC) is controversial even though several studies have explored this association. Therefore, this review article (meta-analysis) has been conducted.

Does a high intake of vegetables and fruit decrease risk of esophageal squamous cell carcinoma?

Study design:
This review article included a total of 32 observational studies involving 10037 cases of esophageal squamous cell carcinoma.

There was no evidence of publication bias.

Results and conclusions:
The investigators found highest vs. lowest vegetable intake, significantly reduced risk of esophageal squamous cell carcinoma with 44% [SRR = 0.56, 95% CI = 0.45-0.69, p-heterogeneity 0.001]. Significant means there is an association with a 95% confidence.

The investigators found highest vs. lowest fruit intake, significantly reduced risk of esophageal squamous cell carcinoma with 47% [SRR = 0.53, 95% CI = 0.44-0.64, p-heterogeneity 0.001].

The investigators found similar results in a linear dose-response analysis and there was evidence of non-linear associations for intakes of fruit [p non-linearity 0.001] and vegetables [p non-linearity = 0.041].

The investigators concluded that intakes of vegetables and fruit reduce risk of esophageal squamous cell carcinoma. Further investigation with prospective designs, validated questionnaires and good control of important confounders is warranted.

Original title:
Intake of fruit and vegetables and risk of esophageal squamous cell carcinoma: A meta-analysis of observational studies by Liu J, Wang J, […], Lv C.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/23319052

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