Nutrition and health

Objectives:
Several epidemiological studies have suggested that vitamin E could reduce the risk of uterine cervical neoplasm. However, controversial data were presented by different reports. Therefore, this review article (meta-analysis) has been conducted.

Do both high vitamin E intake and circulating vitamin E levels reduce risk of uterine cervical neoplasm?

Study design:
This review article included 15 case-control studies, involving 3,741 cases (those with uterine cervical neoplasm) and 6,328 controls (those without uterine cervical neoplasm).

There was no obvious publication bias.

Results and conclusions:
The investigators found in pooled analysis that the highest intake of vitamin E significantly reduced risk of cervical neoplasia with 42% [OR = 0.58, 95% CI = 0.47-0.72, I2 = 83%]. In addition, both vitamin E intake and blood levels of vitamin E were negatively correlated with cervical neoplasia risk.

The investigators found in subgroup analysis that the highest intake of dietary vitamin E significantly reduced risk of cervical neoplasia with 32% [OR = 0.68, 95% CI = 0.49-0.94, I2 = 70%].

The investigators found in subgroup analysis that the highest vitamin E blood levels significantly reduced risk of cervical neoplasia with 48% [OR = 0.52, 95% CI = 0.40-0.69, I2 = 86%].

The investigators found in subgroup analysis that vitamin E significantly reduced risk of cervical neoplasia with 40% [OR = 0.60, 95% CI = 0.45-0.78, I2 = 84%] in studies conducted in America and Europe.

The investigators found in subgroup analysis that the highest intake of vitamin E significantly reduced risk of cervical neoplasia with 46% [OR = 0.54, 95% CI = 0.39-0.76, I2 = 75%] in studies conducted in Asia.

The investigators found subgroup analysis stratified by different types of cervical neoplasm indicated that the highest intake (or serum level) of vitamin E significantly decreased risk of cervical cancer with 47% [OR = 0.53, 95% CI = 0.390.73, I2 = 77%] and cervical intraepithelial neoplasia (CIN) with 46% [OR = 0.54, 95% CI = 0.43-0.70, I2 = 79%]. Meanwhile, sensitivity analysis to assess the influence of each single study on the pooled ORs by omitting a research in each turn, showed combined ORs were not substantially different, indicating that the results of this meta-analysis were stable and reliable.

The investigators concluded that both vitamin E intake and circulating vitamin E levels could reduce cervical neoplasia risk, including cervical cancer and cervical intraepithelial neoplasia. In other words, sufficient supplementation of vitamin E might reduce the risk of cervical neoplasia. However, more randomized controlled trials and cohort studies with high quality are required to further validate this inverse relationship.

Original title:
Effect of vitamin E supplementation on uterine cervical neoplasm: A meta-analysis of case-control studies by Hu X, Li S, [...], Zhu X.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5567498/

Additional information of El Mondo:
Find more information/studies on vitamin E, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

Higher intake of vitamin E is an intake which covers the recommended daily allowance of vitamin E of at least 1 day.

Objectives:
Dietary fat may play a role in lung carcinogenesis. Findings from epidemiologic studies, however, remain inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Is there an association between dietary fat intake and the risk of lung cancer?

Study design:
This review article included 10 prospective cohort studies with a total of 1,445,850 participants, of which 18,822 incident cases (subjects with lung cancer).

The mean follow-up was 9.4 years. 

Results and conclusions:
The investigators found high intakes of total fat were associated with a 7% significant increased risk of lung cancer [for highest v lowest quintile: HR = 1.07, 95% CI = 1.00 to 1.15].

The investigators found high intakes of saturated fat were associated with a 14% significant increased risk of lung cancer [for highest v lowest quintile: HR = 1.14, 95% CI = 1.07 to 1.22].

The investigators found high intakes of saturated fat were associated with a 23% significant increased risk of lung cancer among current smokers [for highest v lowest quintile: HR = 1.23, 95% CI = 1.13 to 1.35, p for trend 0.001].

The investigators found high intakes of saturated fat were associated with a 61% significant increased risk of squamous cell lung cancer [for highest v lowest quintile: HR = 1.61, 95% CI = 1.38 to 1.88].

The investigators found high intakes of saturated fat were associated with a 40% significant increased risk of small cell carcinoma lung cancer [for highest v lowest quintile: HR = 1.40, 95% CI = 1.17 to 1.67].

The investigators found a high intake of polyunsaturated fat was associated with a 8% significant decreased risk of lung cancer [for highest v lowest quintile: HR = 0.92, 95% CI = 0.87 to 0.98, p for trend = 0.02].

The investigators found a 5% energy substitution of saturated fat with polyunsaturated fat was associated with a 16% and 17% lower risk of small cell and squamous cell carcinoma, respectively.

The investigators found no associations for monounsaturated fat.

The investigators concluded that high intakes of polyunsaturated fat decrease risk of lung cancer, while high intakes of saturated fat increase risk of lung cancer, particularly among smokers and for squamous cell and small cell carcinoma.

Original title:
Dietary Fat Intake and Lung Cancer Risk: A Pooled Analysis by Yang JJ, Yu D1, […], Shu XO.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28742456

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

A daily diet with high intakes of saturated fat is a diet that is largely made up of meals/products with more than 10 En% saturated fat, with a small part of meals/products with less than 10 En% saturated fat. Practically, this means that all meals/products that you eat on a daily basis should contain on average more than 10 En% saturated fat.
Check here which products contain more than 10% En% saturated fat.

A daily diet with low intakes of saturated fat is a diet that is largely made up of meals/products with less than 7 En% saturated fat, with a small part of meals/products with more than 7 En% saturated fat. Practically, this means that all meals/products that you eat on a daily basis should contain on average less than 7 En% saturated fat.
Check here which products contain less than 7% En% saturated fat.

Objectives:
Available studies in the literature on the selenium levels in Alzheimer's disease (AD) are inconsistent with some studies reporting its decrease in the circulation, while others reported an increase or no change as compared to controls. Therefore, this meta-analysis (review article) has been conducted.

Do lower circulatory (plasma/serum and blood), erythrocyte and cerebrospinal fluid (CSF) selenium levels increase Alzheimer's disease risk?

Study design:
This review article included 12 case-control/observational studies reporting selenium concentrations in Alzheimer's disease and controls.

Results and conclusions:
The investigators found random-effects meta-analysis indicated a decrease in circulatory [SMD = -0.44], erythrocellular [SMD = -0.52] and cerebrospinal fluid [SMD = -0.14] selenium levels in Alzheimer's disease patients compared to controls

The investigators found stratified meta-analysis demonstrated that the selenium levels were decreased in both the subgroups with [SMD = -0.55] and without [SMD = -0.37] age matching between Alzheimer's disease and controls.

The investigators also found a direct association between decreased selenium levels and glutathione peroxidase (GPx) in Alzheimer's disease.

The investigators concluded that circulatory selenium concentration is significantly lower in Alzheimer's disease patients compared to controls and this decrease in selenium is directly correlated with an important antioxidant enzyme, the glutathione peroxidase, in Alzheimer's disease.

Original title:
A systematic review and meta-analysis of the circulatory, erythrocellular and CSF selenium levels in Alzheimer's disease: A metal meta-analysis (AMMA study-I) by Reddya VS, Bukkeb S, […], Pandeye AK.

Link:
http://www.sciencedirect.com/science/article/pii/S0946672X1630205X%20

Additional information of El Mondo:
Find more information/studies on selenium and dementia right here.
 

Objectives:
Recently, several randomized controlled trials (RCTs) reported the association between the use of vitamin or antioxidant supplements and the risk of bladder cancer. However, those findings remain inconsistent and some studies even reported that vitamin and antioxidant supplements increased the risk of bladder cancer. Therefore, this review article (meta-analysis) has been conducted.

Is there an association between the use of vitamin or antioxidant supplements and the risk of bladder cancer?

Study design:
This review article included 14 RCTs with a total of 147,383 participants, which involved 89,972 in the supplement group and 57,411 in the control group.

The supplementation and follow-up periods ranged between 1 and 13 years.

The types of vitamin and antioxidant supplements were as follows: vitamin A, vitamin B6, vitamin C, vitamin D, vitamin E, beta-carotene, folic acid and selenium.
The dosage regimens in individual trials were as follows: vitamin A (200 mg or 25,000, 36,000 or 40,000 IU daily), vitamin B6 (25 or 100 mg daily), vitamin C (2,000 mg daily), vitamin D (1,600 IU daily), vitamin E (50 mg or 400 IU daily), beta-carotene (20 or 30 mg daily; 50 mg alternate day; 75 mg daily for 3-month cycles), folic acid (1.6 mg daily) and selenium (200 μg daily).

Publication bias was not observed [Begg's funnel plot, symmetrical and Egger's test, p for bias = 0.378].

Results and conclusions:
The investigators found in fixed-effect meta-analysis of all 14 trials that vitamin or antioxidant supplementation was not associated with the risk of bladder cancer [RR = 1.04, 95% CI = 0.92-1.17, I2 = 39.7%].

The investigators found regarding types of supplements, any type of vitamin and antioxidant supplements had no beneficial effect on the risk of bladder cancer:
-vitamin A [RR = 0.86, 95% CI = 0.65-1.13, I2 = 61.7%, n = 5];
-vitamin B6 [RR = 0.77, 95% CI = 0.49-1.20, I2 = 78.8%, n = 3];
-vitamin C [RR = 0.74, 95% CI = 0.36-1.54, I2 = 88.8%, n = 2];
-vitamin D [RR = 1.05, 95% CI = 0.85-1.29, n = 1];
-vitamin E [RR = 0.91, 95% CI = 0.69-1.19, I2 = 60.9%, n = 6];
-beta-carotene [RR = 1.19, 95% CI = 0.96-1.46, I2 = 0.0%, n = 6];
-folate [RR = 1.05, 95% CI = 0.85-1.29, n = 1] and
-selenium [RR = 1.09, 95% CI = 0.81-1.46, I2 = 0.0%, n = 2].

The investigators found overall, there was no significant effect of vitamin and antioxidant supplements in the subgroup meta-analyses by various factors such as dose of supplements, type of cancer prevention, methodological quality, duration of treatment, provider of supplements, type of control and number of participants.
However, the risk of bladder cancer was marginally increased in trials with the use of beta-carotene alone [RR = 1.44, 95% CI = 1.00-2.09, I2 = 0.0%, n = 3].

The investigators concluded that vitamin and antioxidant supplements have no overall preventive effect against bladder cancer. Instead, subgroup meta-analyses showed that beta-carotene supplementation marginally increased the risk of bladder cancer. Even though further large, high-quality trials are required to confirm these associations, the effects (either beneficial or harmful) of vitamin or antioxidant supplements on bladder cancer should not be overemphasized.

Original title:
Effects of Vitamin and Antioxidant Supplements in Prevention of Bladder Cancer: a Meta-Analysis of Randomized Controlled Trials by Park SJ, Myung SK, […], Lee YJ.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5334161/

Additional information of El Mondo:
Find more information/studies on vitamins, selenium, beta-carotene, antioxidants and cancer right here.

Objectives:
Protective effects of calcium supplementation against colorectal adenomas have been documented in systematic reviews; however, the results have not been conclusive. Therefore, this review article (meta-analysis) has been conducted.

Does calcium supplementation reduce colorectal adenomas?

Study design:
This review article included 5 RCTs involving 2,234 patients with a history of adenomas.
Based on visual inspection of the funnel plots as well as on quantitative measurement that used the Egger regression test, there was weak evidence of publication bias.
No major serious adverse events were associated with the use of calcium, but there was an increase in the incidence of hypercalcemia [p  = 0 .0095].
Random errors were evaluated with trial sequential analyses (TSAs). However, TSA indicated a lack of firm evidence for a beneficial effect of calcium supplementation.

Results and conclusions:
The investigators found quantitative pooling of results from all 5 RCTs indicated that the use of supplemental calcium lasting 3 to 5 years showed a statistically significant 17% reduction in risk of any recurrent colorectal adenomas [RR = 0.83, 95% CI = 0.75-0.93, I2  =  8.5%, p  =  0.36].

The investigators found in the sensitivity analysis of 3 trials with low bias risk a statistically significant 12% reduction in the recurrence of any colorectal adenomas [RR = 0.88, 95% CI = 0.79-0.99, I2  =  0%, p  =  0.54] in patients who were administered supplemental calcium versus placebo.

The investigators found no association between supplemental calcium and recurrence of advanced colorectal adenomas in trials with low risk of bias [RR = 1.02, 95% CI = 0.67-1.55, I2 =  17.5%].

The investigators found in the subgroup analysis of 3 trials with elemental calcium dose ≤ 1200 mg/day, a statistically significant 16% reduction in the recurrent of any colorectal adenomas [RR = 0.84, 95% CI = 0.73-0.97, I2  =  38.5%, p  = 0 .19].

However, a greater reduction of 26% [RR = 0.74, 95% CI = 0.56-0.97, I2  =  0%, p  = 0 .70] was observed in the subgroup analysis of 2 trials with elemental calcium dose ≥ 1600 mg/day.
Subgroup analyses demonstrated no statistically significant association with the reduction of advanced colorectal adenomas in any doses.

The investigators concluded the available good quality RCTs suggests a possible beneficial effect of calcium supplementation – preferably at least 1600 mg/day elemental calcium – on the recurrence of colorectal adenomas. However, TSA indicated that the accumulated evidence is still inconclusive. Therefore, large well-designed randomized trials with low risk of bias are needed.

Original title:
Effects of calcium on the incidence of recurrent colorectal adenomas: A systematic review with meta-analysis and trial sequential analysis of randomized controlled trials by Veettil SK, Ching SM, […], Chaiyakunapruk N.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5556213/

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

Colorectal adenomas can lead to colorectal cancer.

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:
Does higher protein intake increase bone mineral density?

Study design:
This review article included 6 RCTs and 20 prospective cohort studies.
There were no adverse effects of higher protein intakes.
Studies were heterogeneous and confounding could not be excluded.

Results and conclusions:
The investigators found moderate evidence suggested that higher protein intake may have a protective effect on lumbar spine bone mineral density compared with lower protein intake [net percentage change = 0.52%, 95% CI = 0.06%-0.97%, I2 = 0%, n = 5] but had no effect on total hip, femoral neck, or total body bone mineral density or bone biomarkers.

The investigators concluded that higher protein intake may have a protective effect on lumbar spine bone mineral density. May have because studies were heterogeneous and confounding could not be excluded. Therefore, high-quality, long-term studies are needed to clarify dietary protein's role in bone health.

Original title:
Dietary protein and bone health: a systematic review and meta-analysis from the National Osteoporosis Foundation by Shams-White MM, Chung M, […], Weaver CM.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28404575

Additional information of El Mondo:
Find more information/studies on protein and elderly right here.

A higher protein diet is a diet with 20-35 En% protein. The easiest way to meet a diet with 20-35 En% protein is to choose food items/meals with also 20-35 En% protein. Check here which products contain 20-35 En% protein.
 

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:
Current studies evaluating the association of tea consumption and bone mineral density (BMD) have yielded inconsistent findings. Therefore, this meta-analysis (review article) has been conducted.

Does tea consumption increase bone mineral density?

Study design:
This review article included 4 cohort, 1 case-control and 8 cross-sectional studies including a total of 12,635 cases (6,059 in the tea consumption group and 6,576 individuals in non-tea consumption group).

Results and conclusions:
The investigators found tea consumption significantly reduced the occurrence of low bone mass with 34% [OR  =  0.66, 95% CI  =  0.47-0.94, p =  0.02].

The investigators found tea consumption significantly yielded higher mineral densities in several bones, including:
-the lumbar spine [standardized mean difference (SMD) = 0.19, 95% CI = 0.08-0.31, p  =  0.001];
-hip [SMD = 0.19, 95% CI = 0.05-0.34, p  =  0.01];
-femoral neck [mean difference (MD) = 0.01, 95% CI = 0.00-0.02, p  =  0.04];
-Ward triangle [MD = 0.02, 95% CI = 0.01-0.04, p  =  0.001] and;
-greater trochanter [MD = 0.03, 95% CI = 0.02-0.04, p  0.00001]
than the non-tea consumption group.

The investigators concluded that tea consumption increases bone mineral density, especially in the lumbar spine, hip, femoral neck, Ward triangle and greater trochanter, which can prevent bone loss.

Original title:
Updated association of tea consumption and bone mineral density: A meta-analysis by Zhang ZF, Yang JL, [...], Liu ZX.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5371490/

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

Objectives:
Is there a relationship between serum 25(OH)D (vitamin D blood level) and mortality risk in the general population?

Study design:
This review article included 14 prospective cohort studies that involved 5562 deaths out of 62548 individuals.
In the parametric model, which is based on 11 studies and 59231 individuals, the lowest quantile as the reference category has been used.

Evidence of heterogeneity for the RR was apparent when highest were compared with lowest categories [p = 0.008, I2 = 58%].

There was no evidence of publication bias.

Results and conclusions:
The investigators found for “highest compared with lowest” categories of 25(OH)D, a significant reduced risk of 29% for mortality [RR = 0.71, 95% CI = 0.50-0.91].

The investigators found in the parametric model, the estimated summary RRs of mortality were 0.86 [95% CI = 0.82-0.91], 0.77 [95% CI = 0.70-0.84] and 0.69 [95% CI = 0.60-0.78] for individuals with an increase of 12.5, 25 and 50 nmol 25(OH)D serum values/L, respectively, from a median reference category of ∼27.5 nmol/L.
However, no significant decrease in mortality was found above ∼87.5 nmol/L.

The investigators concluded there is a nonlinear decrease in mortality risk as circulating 25(OH)D increases, with optimal concentrations ∼75-87.5 nmol/L. Because many adults do not achieve these 25(OH)D values, large prospective randomized trials are urgently needed to investigate whether vitamin D supplementation is able to reduce mortality risk in the general population.

Original title:
Vitamin D deficiency and mortality risk in the general population: a meta-analysis of prospective cohort studies by Zittermann A, Iodice S, [...], Gandini S.

Link:
http://ajcn.nutrition.org/content/95/1/91.full

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

Objectives:
Does soy isoflavone reduce the frequency and severity of hot flashes?

Study design:
This review article included 19 trials (13 included hot flash frequency, of which 10 for severity and 3 for composite scores).
17 trials were selected for meta-analyses to clarify the effect of soybean isoflavones on hot flash frequency (13 trials) and severity (9 trials).

Results and conclusions:
The investigators found intake of soy isoflavones (median = 54 mg aglycone equivalents) for 6 weeks to 12 months significantly reduced the frequency (combined fixed-effect and random effects model) of hot flashes by 20.6% [95% CI = -28.38 to -12.86, p 0.00001] compared with placebo [p heterogeneity = 0.0003, I2 = 67% for random effects model].

The investigators also found isoflavones significantly reduced hot flash severity by 26.2% [95% CI = -42.23 to -10.15, p = 0.001] compared with placebo [p heterogeneity 0.00001, I2 = 86% for random effects model].

The investigators found isoflavone supplements providing more than 18.8 mg of genistein (the median for all studies) were more than twice as potent at reducing hot flash frequency than lower genistein supplements.

The investigators concluded soy isoflavone supplements (54 mg per day for 6 weeks to 12 months), derived by extraction or chemical synthesis, are significantly more effective than placebo in reducing the frequency and severity of hot flashes. Additional studies are needed to further address the complex array of factors that may affect efficacy, such as dose, isoflavone form, baseline hot flash frequency and treatment duration.

Original title:
Extracted or synthesized soybean isoflavones reduce menopausal hot flash frequency and severity: systematic review and meta-analysis of randomized controlled trials by Taku K, Melby MK, […], Messina M.

Link:
http://journals.lww.com/menopausejournal/Abstract/2012/07000/Extracted_or_synthesized_soybean_isoflavones.11.aspx

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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

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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

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Objectives:
There is an ongoing debate on the involvement of systemic copper (Cu) dysfunctions in Alzheimer's disease (AD) and clinical studies comparing Cu levels in serum, plasma and cerebrospinal fluid (CSF) of AD patients with those of healthy controls have delivered non-univocal and often conflicting results. Therefore, this review article has been conducted.

Does blood level of copper increase in Alzheimer’s disease?

Study design:
This review article included 26 studies including a pooled total of 761 AD subjects and 664 controls for serum Cu studies, 205 AD subjects and 167 controls for plasma Cu and of 116 AD subjects and 129 controls for CSF Cu.

Results and conclusions:
The investigators found Alzheimer's disease patients have higher levels of serum copper than healthy controls. Plasma data did not allow conclusions, due to their high heterogeneity, but the meta-analysis of the combined serum and plasma studies confirmed higher copper levels in Alzheimer's disease patients. 

The investigators found the analysis of CSF data revealed no difference between Alzheimer's disease patients and controls.

The investigators concluded Alzheimer's disease patients have higher levels of serum and plasma copper than healthy controls.

Original title:
Copper in Alzheimer's disease: a meta-analysis of serum, plasma, and cerebrospinal fluid studies by Bucossi S, Ventriglia M, […], Squitti R.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/21187586

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Objectives:
The association between dietary vitamin K intake and the risk of fractures is controversial. Therefore, this meta-analysis (review article) has been conducted.

Does dietary vitamin K intake reduce risk of fractures?

Study design:
This review article included 4 cohort studies and 1 nested case-control study, including 80,982 total subjects and 1114 fracture cases.

The fractures were assessed using confirmed self-reported, medical and radiological report. Dietary vitamin K intake was assessed with a food-frequency questionnaire (FFQ) in 4 studies, only 1 study used 4-day or 7-day food record.
Vitamin K intake in all included studies refers exclusively to the intake of phylloquinone (vitamin K1), which is the predominant form of vitamin K in foods.
All subjects were more than 30 years old.
Duration of follow-up for the included studies ranged from 6.9 to 10 years.
Most studies provided RRs that were adjusted for age, BMI, BMD, physical activity, vitamin D and calcium intake, smoking and alcohol consumption.

The Begg and Egger tests did not show any substantial asymmetry (p  =  0.50 for Begg test and p  =  0.32 for Egger tests). Further trim and filled meta-analysis showed that there were no trimming data added.

Results and conclusions:
The investigators found for highest vs. the lowest dietary vitamin K intake a significant reduced risk of 22% [RR = 0.78, 95% CI = 0.56-0.99, I2  =  59.2%, p  = 0 .04] for fractures.

The investigators found for every increment of 50μg dietary vitamin K intake per day a significant reduced risk of 3% [RR  = 0.97, 95% CI = 0.95-0.99, I2  =  25.9%, p  = 0 .25] for fractures.

The investigators found a significant reduced risk of 24% [RR = 0.76, 95% CI = 0.58-0.93, I2  =  59.2%, p  = 0 .04] for fractures in studies with more than 10 years of follow-up.

The investigators concluded that higher dietary vitamin K intake; at least 50μg dietary vitamin K intake per day decreases the risk of fractures. This review article offers additional evidence on the relationship between dietary vitamin K intake and risk of fractures. The benefit of vitamin K should be confirmed in future well-designed prospective cohort studies and clinical trials.

Original title:
Vitamin K intake and the risk of fractures: A meta-analysis by Hao G, Zhang B, [...], Cao X.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5413254/

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Objectives:
In view of the vital role of oxidative stress in the pathogenesis of Alzheimer's disease (AD), the potential of antioxidant supplements to prevent AD have gained much interest, while there are conflicting results on this topic in recent years. Therefore, this review article has been conducted.

Does dietary intake of vitamin C and E and β-carotene decrease risk of Alzheimer's disease?

Study design:
This review article included 7 articles (dietary intake, but no supplements).

Results and conclusions:
The investigators found a significant decreased risk for Alzheimer disease of 24% [pooled relative risk = 0.76 95% CI = 0.67-0.84] for dietary intake of vitamin E and of 17% [pooled relative risk = 0.83, 95% CI = 0.72-0.94] for dietary intake of vitamin C.

However, the investigators found a non-significant decreased risk of 12% [pooled relative risk = 0.88, 95% CI = 0.73-1.03] for dietary intake of β-carotene.

The investigators concluded dietary intakes of vitamin C and E lower the risk of Alzheimer's disease, with vitamin E exhibiting the most pronounced protective effects. The findings will be of significance to the prevention and interventional treatment of Alzheimer's disease.

Original title:
Dietary intakes of vitamin E, vitamin C, and β-carotene and risk of Alzheimer's disease: a meta-analysis by Li FJ, Shen L and Ji HF.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/22543848

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Objectives:
Manganese (Mn) is one of the most studied environmental heavy metals linked to Alzheimer’s disease (AD). However, it remains unclear whether serum manganese levels are associated with Alzheimer’s disease and mild cognition impairment (MCI, a prodromal stage of AD). Therefore, this meta-analysis (review article) has been conducted.

Does a lower serum manganese level increase risk of cognitive decline?

Study design:
This review article included 17 studies, involving 836 cases and 1254 health controls (HC).

The sample size of the included studies ranged from 8 to 758. The average age of the patient groups ranged from 66.2 to 87.0 years. The proportion of female patients ranged from 33% to 80%.

Strong heterogeneity existed among the studies. Heterogeneity was not due to methods for measuring manganese levels, geographic locations, age and gender of patients.

There was no publication bias in the present meta-analysis evaluated by the Egger’s test (p = 0.258) and Begg’s test (p = 0.107).

Results and conclusions:
The investigators found random-effects meta-analysis showed that patients with Alzheimer’s disease had significantly reduced serum manganese levels compared with health control subjects [SMD = -0.39, 95% CI = -0.71 to -0.08, p = 0.015].

The investigators found mild cognition impairment individuals had a tendency toward reduced serum manganese levels compared with health control subjects [SMD = -0.31, 95% CI = -0.70 to 0.08, p = 0.117].

The investigators found a significant decrease in serum manganese levels in patients with cognitive impairment (including both AD patients and MCI patients) [SMD = -0.37, 95% CI = -0.60 to -0.13, p = 0.002].

The investigators found no significant differences between Alzheimer’s disease and mild cognition impairment patients in serum levels [SMD = 0.24, 95% CI = -0.23 to 0.72, p = 0.310].

The investigators concluded that the serum manganese levels are lower in Alzheimer’s disease patients and manganese deficiency may be a risk factor for Alzheimer’s disease. However, the results should be interpreted with caution due to the high heterogeneity of the studies.

Original title:
Association of Serum Manganese Levels with Alzheimer’s Disease and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis by Du K, Liu M, [...], Wei M.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5372894/

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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:
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:
Lutein and zeaxanthin are thought to have beneficial effects on protecting the lens against cataract formation, but findings from epidemiologic studies have been inconsistent. Therefore, this review article has been conducted.

Does dietary lutein and zeaxanthin intake reduce age-related cataract risk?

Study design:
This review article included 6 prospective cohort studies, involving 4416 cases and 41999 participants.

Results and conclusions:
The investigators found for comparing the highest with the lowest categories of dietary lutein and zeaxanthin intake, a significant reduced risk for nuclear cataract of 25% [RR = 0.75, 95% CI = 0.65-0.85], but the reduced risk was not significant for cortical cataract [RR = 0.85, 95% CI = 0.53-1.17] and for posterior subcapsular cataract [RR = 0.77, 95% CI = 0.40-1.13]. Significant means, there is an association with a 95% confidence.

The investigators found in dose-response analysis that every 300 μg/d increment in dietary lutein and zeaxanthin intake was significantly associated with a 3% [RR = 0.97, 95% CI = 0.94-0.99] reduction in the risk of nuclear cataract.

The investigators found in dose-response analysis that every 300 μg/d increment in dietary lutein and zeaxanthin intake was non-significantly associated with a 1% [RR = 0.99, 95% CI = 0.95-1.02] reduction in the risk of cortical cataract. Non-significantly means, there is no association with a 95% confidence.

The investigators found in dose-response analysis that every 300 μg/d increment in dietary lutein and zeaxanthin intake was non-significantly associated with a 3% [RR = 0.97, 95% CI = 0.93-1.01] reduction in the risk of posterior subcapsular cataract. Non-significantly because RR of 1 was found in 95% CI of 0.93 to 1.01. RR of 1 means no risk.

The investigators concluded dietary lutein and zeaxanthin intake (at least 300 μg/d) is associated with a reduced risk of age-related cataract, especially nuclear cataract in a dose-response manner, indicating a beneficial effect of lutein and zeaxanthin in age-related cataract prevention.

Original title:
A dose–response meta-analysis of dietary lutein and zeaxanthin intake in relation to risk of age-related cataract by Ma L, Hao ZX, [...], Pan JP.

Link:
http://link.springer.com/article/10.1007/s00417-013-2492-3

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