Nutrition and health

Objectives:
Does dietary intake of fiber reduce risk of endometrial cancer?

Study design:
This review article included 16 studies, involving 6,563 cases (persons with endometrial cancer).

Results and conclusions:
The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 14% [RR = 0.86, 95% CI = 0.78 to 0.93].
In stratified analysis, this trend was more pronounced in the case-control studies and in studies conducted in the Americas and Asia.

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 26% after adjusting for education level [RR = 0.74, 95% CI = 0.60 to 0.88].

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 30% after adjusting for age [RR = 0.70, 95% CI = 0.57 to 0.83].

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 19% in studies with NOS scores of 6 (the higher the NOS scores, the more reliable the studies are) [RR = 0.81, 95% CI = 0.67 to 0.95].

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 25% in studies with NOS scores of 7 [RR = 0.75, 95% CI = 0.62 to 0.88].

The investigators concluded dietary fiber intake reduces risk of endometrial cancer. Further efforts should be made to confirm these findings.

Original title:
Association between dietary fiber and endometrial cancer: a meta-analysis by Li H, Mao H, [...], Nan Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31584301

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Objectives:
Some evidence indicates that carotenoids may reduce the risk of bladder cancer (BC), but the association is unclear. Therefore, this review article has been conducted.

Do carotenoids (β-cryptoxanthin, α-carotene, β-carotene and lutein and zeaxanthin) reduce risk of bladder cancer?

Study design:
This review article included a total of 22 studies (case-control and cohort studies) involving 516,740 adults.

Results and conclusions:
The investigators found for the highest compared with the lowest category of carotenoid dietary intake a non-significantly reduced risk of 12% [RR = 0.88, 95% CI = 0.76 to 1.03] for bladder cancer.
Non-significantly because RR of 1 was found in the 95% CI of 0.76 to 1.03. RR of 1 means no risk/association.

The investigators found for the highest compared with the lowest category of circulating carotenoid concentrations a non-significantly reduced risk of 64% [RR = 0.36, 95% CI = 0.12 to 1.07] for bladder cancer.

The investigators found for the highest compared with the lowest category of circulating lutein and zeaxanthin concentrations a significantly reduced risk of 47% [RR = 0.53, 95% CI = 0.33 to 0.84] for bladder cancer.
Significantly because RR of 1 was not found in the 95% CI of 0.33 to 0.84. RR of 1 means no risk/association.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 42% [RR = 0.58, 95% CI = 0.36 to 0.94] for every 1 mg increase in daily dietary β-cryptoxanthin intake.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 76% [RR = 0.24, 95% CI = 0.08 to 0.67] for every 1 μmol/L increase in circulating concentration of α-carotene.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 27% [RR = 0.73, 95% CI = 0.57 to 0.94] for every 1 μmol/L increase in circulating concentration of β-carotene.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 56% [RR = 0.44, 95% CI = 0.28 to 0.67] for every 1 μmol/L increase in circulating concentrations of lutein and zeaxanthin.

The investigators concluded dietary β-cryptoxanthin intake and circulating concentrations of α-carotene, β-carotene and lutein and zeaxanthin reduce risk of bladder cancer.

Original title:
Carotenoid Intake and Circulating Carotenoids Are Inversely Associated with the Risk of Bladder Cancer: A Dose-Response Meta-analysis by Wu S, Liu Y, […], Ramirez AG.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31800007

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Objectives:
Is there an association between dietary fat intake and the risk of three major types of skin cancer including basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and cutaneous malignant melanoma (CMM)?

Study design:
This review article included 3 prospective cohort studies (175,675 participants and 30,915 basal cell carcinoma cases, 4,106 squamous cell carcinoma cases and 1,638 cutaneous malignant melanoma cases) and 9 case-control studies (328 basal cell carcinoma cases, 493 squamous cell carcinoma cases, 1,547 cutaneous malignant melanoma cases and 2,660 controls).

Results and conclusions:
The investigators found pooled results indicated that dietary consumption of total fat and saturated fat were not associated with 3 major types of skin cancer.

The investigators found high consumption of monounsaturated fat was significantly associated with a decreased risk of 10% for basal cell carcinoma [RR = 0.90, 95% CI = 0.85 to 0.96]. 

The investigators found high consumption of polyunsaturated fat was significantly associated with an increased risk of 19% for squamous cell carcinoma [RR = 1.19, 95% CI = 1.06 to 1.33]. 

The investigators concluded high consumption of monounsaturated fat decreases risk of basal cell carcinoma while high consumption of polyunsaturated fat increases risk of squamous cell carcinoma. However, these findings should be confirmed by further evidence from well-designed and large-scale prospective cohort studies.

Original title:
Dietary Fat Intake and the Risk of Skin Cancer: A Systematic Review and Meta-Analysis of Observational Studies by Ruan L, Cheng SP and Zhu QX.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31298947

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Objectives:
The results of epidemiological studies on the relationship between fruit and vegetable intake and lung cancer risk were inconsistent among participants with different smoking status. Therefore, this review article has been conducted.

Do dietary intakes of fruit and vegetables reduce risk of lung cancer?

Study design:
This review article included a total of 12 prospective cohort studies.
The duration of follow-up ranged from 4 to 12.9 years.
No publication bias was found.

Results and conclusions:
The investigators found for dietary consumption of fruit a significantly reduced risk of 14% [summary RR = 0.86, 95% CI = 0.78 to 0.94, I2 = 0.0%, p = 0.642] for lung cancer among current smokers.

Significant means that there is an association with a 95% confidence.

The investigators found for dietary consumption of fruit a significantly reduced risk of 9% [summary RR = 0.91, 95% CI = 0.84 to 0.99, I2 = 0.0%, p = 0.653] for lung cancer among former smokers.
Significant because RR of 1 was not found in the 95% CI of 0.84 to 0.99. RR of 1 means no risk/association.

The investigators found stratified analysis showed that dietary consumption of fruit significantly reduced risk of lung cancer with 23% [RR = 0.77, 95% CI = 0.62 to 0.96] in current smoking subjects from Europe.

The investigators found in linear dose-response analysis that an increase of 100 grams of fruit intake per day was associated with a 5% reduction [RR = 0.95, 95% CI = 0.93 to 0.97, p for trend 0.001] in current smokers.

The investigators found in linear dose-response analysis that an increase of 100 grams of fruit intake per day was associated with a 5% reduction [RR = 0.95, 95% CI = 0.93 to 0.99, p for trend = 0.001] in former smokers.

The investigators found for dietary consumption of vegetables a significantly reduced risk of 13% [summary RR = 0.87, 95% CI = 0.78 to 0.97, I2 = 25.4%, p = 0.226] for lung cancer among current smokers.

The investigators found in linear dose-response analysis that an increase of 100 grams of vegetable intake per day was associated with a 3% lower risk of lung cancer in current smokers [95% CI = 0.96 to 1.00, p for trend = 0.057]. 

The investigators concluded that fruit consumption, at least 100g per day decreases lung cancer risk among current smokers and former smokers, while vegetables consumption, at least 100g per day decreases lung cancer risk of current smokers. These findings may have considerable public health significance for the prevention of lung cancer through dietary interventions.

Original title:
The Associations of Fruit and Vegetable Intake with Lung Cancer Risk in Participants with Different Smoking Status: A Meta-Analysis of Prospective Cohort Studies by Wang C, Yang T, [...], Li D.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723574/

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Objectives:
Findings of epidemiological studies regarding the association between carrot consumption and lung cancer risk remain inconsistent. Therefore, this review article has been conducted.

Do dietary intakes of carrot reduce risk of lung cancer?

Study design:
This review article included a total of 17 case-control studies and 1 prospective cohort study, involving 202,969 individuals and 5,517 patients with lung cancer.

Results and conclusions:
The investigators found in 18 studies a significantly reduced risk of 42% [pooled OR = 0.58, 95% CI = 0.45 to 0.74] for lung cancer by comparing the highest category with the lowest category of carrot consumption.
Exclusion of any single study did not materially alter the pooled OR.

The investigators found based on subgroup analyses for the types of lung cancer a significantly reduced risk of 66% [pooled OR = 0.34, 95% CI = 0.15 to 0.79] for the lung cancer adenocarcinoma by comparing the highest category with the lowest category of carrot consumption.

The investigators found based on subgroup analyses for the types of lung cancer a significantly reduced risk of 39% [OR = 0.61, 95% CI = 0.46 to 0.81] for mixed types of lung cancer by comparing the highest category with the lowest category of carrot consumption.

The investigators concluded that carrot consumption decreases the risk of lung cancer, especially for adenocarcinoma.

Original title:
Is carrot consumption associated with a decreased risk of lung cancer? A meta-analysis of observational studies by Xu H, Jiang H, […], Lu Z.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31552816

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Objectives:
Observational studies have reported controversial evidence of the association between dietary fat intake and ovarian cancer. Therefore, this review article has been conducted.
Does dietary fat intake increase risk of ovarian cancer among women?

Study design:
This review article included 21 observational studies involved approximately 900,000 women.

Results and conclusions:
The investigators found a significant nonlinear association between dietary total fat intake with the risk of ovarian cancer, with a relatively steep slope at dietary total fat intake higher than 30 g/day [p non-linearity 0.01].

The investigators found, moreover, the risk of ovarian cancer was increased in non-linear form for both saturated and monounsaturated fat from 25 g/day [p non-linearity 0.05].

The investigators found in linear meta-analysis a 2% greater risk of ovarian cancer per 10 g/day increase in total dietary fat intake.

The investigators found in linear meta-analysis a 2% greater risk of ovarian cancer per 0.5 g/day increase in dietary trans fat intake.

The investigators found in linear meta-analysis a 1% greater risk of ovarian cancer per 2.5 g/day increase in dietary monounsaturated fat intake.
However, this association for monounsaturated fat was marginally significant [p = 0.052].

The investigators found in linear meta-analysis a 1% greater risk of ovarian cancer per 50 mg/day increase in dietary cholesterol intake.

The investigators concluded that dietary total, trans, saturated and partially monounsaturated fat as well as cholesterol intake increase risk of ovarian cancer among women.

Original title:
Dietary Fat Intake and Risk of Ovarian Cancer: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies by Sadeghi A, Shab-Bidar S, […], Djafarian K.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31058552

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Objectives:
Iron has been shown to promote breast carcinogenesis in animal models through generation of oxidative stress and interaction with estrogen. Heme iron, which is found exclusively in animal-sourced foods, is suggested to have a more detrimental effect. Epidemiological evidence of the association between iron and breast cancer risk remains inconclusive and has not been comprehensively summarized. Therefore, this review article has been conducted.

Does dietary iron consumption increase breast cancer risk?

Study design:
This review article included 15 case-control studies and 12 prospective cohort studies.

Of the 17 studies assessing iron intake, 7 were cohort studies with study size ranging from 4,646 to 193,742 participants, follow-up ranging from 5.5 to 20 years and number of breast cancer cases ranging from 188 to 9,305. The remaining 10 studies were case-control studies, of which 4 were hospital-based, 3 were population-based and 3 were nested within existing cohorts, with case numbers ranging from 220 to 3,452.

Of the 11 studies assessing body iron status, 5 were cohort studies with study size ranging from 1,795 to 164,355 participants, follow-up ranging from 7.1 to 17.6 years and number of cases ranging from 80 to 3,238. The remaining 6 studies used a nested case-control or case-cohort design, with follow-up (where reported) ranging from 4 to 15.7 years and case numbers ranging from 107 to 795.

Overall, NOS scores ranged from 4 to 9 (mean = 7.0).

No publication bias was found.

Results and conclusions:
The investigators found compared to lowest category, highest dietary heme iron intake significantly increased risk of breast cancer with 12% [pooled RR = 1.12, 95% CI = 1.04-1.22, I2 = 39%, p heterogeneity = 0.15].

The investigators found each 1 mg/day increase in dietary heme iron intake, was associated with a statistically significant 8% increase in breast cancer risk [pooled RR = 1.08, 95% CI = 1.002–1.17].

The investigators found compared to lowest levels, highest serum iron levels significantly increased risk of breast cancer with 22% [pooled RR = 1.22, 95% CI = 1.01-1.47, I2 = 61%, p heterogeneity = 0.04].

The investigators found serum iron levels exhibited a J-shaped dose-response relationship with breast cancer risk, with strong evidence of a nonlinear effect [p nonlinearity  0.001].

Specifically, a steady increase in risk was noted for serum iron levels above ~ 100 μg/dL, with the association becoming statistically significant at just beyond ~ 125 μg/dL.

The investigators concluded that higher dietary heme iron intake and higher serum iron levels increase breast cancer risk. Further research is needed to better elucidate the association between iron intake/status and risk of breast cancer.

Original title:
Iron intake, body iron status, and risk of breast cancer: a systematic review and meta-analysis by Chang VC, Cotterchio M and Khoo E.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6555759/

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Objectives:
Is there an association between poultry and egg consumption and brain cancer risk?

Study design:
This review article included a total of 10 articles (6 articles for poultry consumption and 5 articles for egg consumption).

Results and conclusions:
The investigators found no association between poultry consumption and reduced risk of brain cancer [summarized relative risk = 0.901, 95% CI = 0.703-1.154, I2 = 60.7%, p = 0.018].
No association because RR of 1 was found in the 95% CI of 0.703 to 1.154. RR of 1 means no risk/association.

The investigators found in 4 studies no association between poultry consumption and reduced risk of brain cancer glioma [summarized relative risk = 0.873, 95% CI = 0.737-1.034, I2 = 0.0%, p = 0.838].

The investigators found no association between egg consumption and reduced risk of brain cancer [summarized relative risk = 0.998, 95% CI = 0.552-1.805, I2 = 82.6%, p = 0.001].

The investigators found no association between egg consumption and increased risk of brain cancer glioma [summarized relative risk = 1.472, 95% CI = 0.935-2.316].

The investigators concluded that poultry and egg consumption are not associated with the risk of brain cancer. Due to the limited quality of evidence currently available, more studies related to poultry and egg consumption for brain cancer is necessary.

Original title:
A meta-analysis of the association between poultry and egg consumption and the risk of brain cancer by Luo H, Sun P, [...], Guo Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30782302

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Objectives:
Previous studies had demonstrated some associations between coffee and tea consumption and brain cancer risk resulted in an inconsistent relationship. Therefore, this review article has been conducted.

Does coffee or tea consumption reduce brain cancer risk?

Study design:
This review article included 8 cohort studies and 3 case-control studies, involving 2,583 cases (persons with brain cancer) among 1,684,262 participants.

Based on Egger’s test and funnel plot, there existed no publication bias.

Results and conclusions:
The investigators found highest category of coffee consumption significantly reduced risk of brain cancer with 21.5% [RR = 0.785, 95% CI = 0.580-0.984, I2 = 65.6%, p for heterogeneity = 0.001], when compared with the lowest category.

The investigators found in supgroup analysis highest category of coffee consumption significantly reduced risk of glioma with 24% [RR = 0.760, 95% CI = 0.548-0.972], when compared with the lowest category.

The investigators found in cohort studies highest category of coffee consumption significantly reduced risk of brain cancer with 14.2% [RR = 0.858, 95% CI = 0.700-0.992], when compared with the lowest category. However, this reduced risk was not significant in case-control studies.

The investigators found highest category of coffee consumption significantly reduced risk of brain cancer with 88.3% in Asian populations [RR = 0.217, 95% CI = 0.042-0.896], when compared with the lowest category. However, this reduced risk was not significant in other populations.

The investigators found sensitivity analysis showed pooled RR of coffee consumption ranged from 0.738 [95% CI = 0.542-0.961) to 0.905 [95% CI = 0.754-1.088].

The investigators found highest category of tea consumption significantly reduced risk of brain cancer with 20.2% in American populations [RR = 0.798, 95% CI = 0.646-0.986], when compared with the lowest category.

The investigators found sensitivity analysis showed pooled RR of tea consumption ranged from 0.863 [95% CI = 0.699-1.067] to 0.947 [95% CI = 0.763-1.176].

The investigators found highest category of coffee plus tea consumption significantly reduced risk of brain cancer with 31.6% [RR = 0.684, 95% CI = 0.481-0.975], when compared with the lowest category.

The investigators concluded higher consumption of coffee reduces risk of brain cancer in Asian populations and higher consumption of tea reduces risk of brain cancer in American population. However, future studies with detailed information about sex, lifestyle and some other related factors are warranted to further explore the association between coffee or tea consumption and risk of brain cancer.

Original title:
Association between tea and coffee consumption and brain cancer risk: an updated meta-analysis by Song Y, Wang Z, [....], Guo J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6419842/

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Objectives:
Results from earlier publications on the association of coffee and caffeine and risk of ovarian cancer are inconsistent. Therefore, this review article has been conducted.

Is there an association between coffee and caffeine consumption and risk of ovarian cancer among women?

Study design:
This review article included 22 case-control studies with a total of 40,140 participants, of which 8,568 patients with ovarian cancer. The participants were ≥ 17 years.

Results and conclusions:
The investigators found combining 21 effect sizes from 18 studies, no significant association was observed between total coffee consumption and risk of ovarian cancer [OR = 1.09, 95% CI = 0.94 to 1.26].

The investigators found no significant association between total caffeine intake and ovarian cancer risk [OR = 0.89, 95% CI = 0.55 to 1.45].

The investigators found, in addition, caffeinated coffee intake was not significantly associated with ovarian cancer risk [OR = 1.05, 95% CI = 0.87 to 1.28].

The investigators found, however, combining effect sizes from 5 studies, an inverse significant association between decaffeinated coffee intake and risk of ovarian cancer [OR = 0.72, 95% CI = 0.58 to 0.90].

The investigators concluded decaffeinated coffee consumption could reduce risk of ovarian cancer among women. Could reduce because this review article only included case-control studies and no cohort studies.

Original title:
Coffee and caffeine intake and risk of ovarian cancer: a systematic review and meta-analysis by Shafiei F, Salari-Moghaddam A , […], Esmaillzadeh A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30833443

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Objectives:
Do omega-3 fatty acids in fish consumption reduce risk of breast cancer in Asian patients?

Study design:
This review article included 4 cohort studies and 7 case-control studies with a total of 130,365 Asian patients.

There was not any study with significant publication bias included.

Results and conclusions:
The investigators found omega-3 fatty acids in fish consumption significantly reduced risk of  breast cancer in Asian patients with 20% [OR = 0.80, 95% CI = 0.73-0.87, p 0.00001].
Significant because OR of 1 was not found in the 95% CI of 0.73 to 0.87. OR of 1 means no risk/association.

The investigators concluded omega-3 fatty acids in fish consumption reduce breast cancer risk in Asian patients.

Original title:
Protective Effect of Omega-3 Fatty Acids in Fish Consumption Against Breast Cancer in Asian Patients: A Meta-Analysis by Nindrea RD, Aryandono T, […], Dwiprahasto I.

Link:
http://journal.waocp.org/?sid=Entrez:PubMed&id=pmid:30803190&key=2019.20.2.327

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Fish containing omega-3 fatty acids are salmon, mackerel, herring, lake trout, bluefin tuna, sturgeon, sablefish, anchovy, albacore tuna, whitefish, arctic char, sardines, bluefish, mullet, halibut, striped bass, mahi mahi, pollock, rockfish, rainbow trout, shark, catfish, carp, cod, flounder, grouper, haddock, ocean perch, red snapper, swordfish, pike, sole and tilapia.

Objectives:
Although the relationship between dietary intake and serum levels of trans fatty acids and risk of breast cancer has been investigated extensively, findings are inconsistent. Therefore, this review article has been conducted.

Do dietary intake and serum levels of trans fatty acids increase risk of breast cancer?

Study design:
This review article included 6 cohort studies and 1 nested case-control study on total dietary trans fat intake and 1 cohort study and 4 nested case-control studies on serum trans fatty acids.

Participants were apparently healthy aged 26 years or older.

Results and conclusions:
The investigators found no significant relationship between dietary intake of total trans fatty acids and risk of breast cancer [pooled effect size = 1.02, 95% CI = 0.95-1.10, p = 0.403].

The investigators found in 3 effect sizes from 2 cohort studies and 1 nested case-control study, no significant relation between dietary intake of conjugated linoleic acid (CLA) and risk of breast cancer [pooled effect size = 1.05, 95% CI = 0.95-1.17, p = 0.513].

The investigators found based on 5 effect sizes, each additional 1 g/day dietary intake of total trans fats was not significantly associated with risk of breast cancer [RR = 1.00, 95% CI = 0.99-1.01].

The investigators found high serum levels of trans fats were associated with an increased risk of 37% of breast cancer among postmenopausal women [pooled effect size = 1.37, 95% CI = 1.04-1.81, p = 0.02].

The investigators concluded dietary intake of trans fatty acids (also called trans fats) is not associated with risk of breast cancer. However, a significant positive association is seen between serum trans fats and risk of breast cancer in postmenopausal women.

Original title:
Dietary intake and serum levels of trans fatty acids and risk of breast cancer: A systematic review and dose-response meta-analysis of prospective studies by Anjom-Shoae J, Sadeghi O, […], Esmaillzadeh A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30954361

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Objectives:
Epidemiological studies focusing on the association between folate and breast cancer risk reported inconsistent findings. Therefore, this review article has been conducted.

Does dietary folate intake reduce breast cancer risk?

Study design:
This review article included a total of 23 prospective cohort studies involving 41,516 cases (=women with breast cancer) among 1,171,048 individuals.

Results and conclusions:
The investigators found dietary folate intake significantly reduced risk of oestrogen-receptor-negative breast cancer with 12% [pooled risk ratio = 0.88, 95% CI = 0.78-1.00].

The investigators found dietary folate intake significantly reduced risk of oestrogen-receptor-negative/progesterone-receptor-negative breast cancer with 18% [pooled risk ratio = 0.82, 95% CI = 0.68-0.97].

The investigators found an increment of dietary folate intake of 100 μg per day was associated with a deceased risk of oestrogen-receptor-negative breast cancer with 6% [RR = 0.94, 95% CI = 0.88-0.99].

The investigators found an increment of dietary folate intake of 100 μg per day was associated with a deceased risk of oestrogen-receptor-negative/progesterone-receptor-negative breast cancer with 10% [RR = 0.90, 95% CI = 0.85-0.97].

The investigators found high dietary folate intake significantly reduced breast cancer risk in premenopausal women with 6% [RR = 0.94, 95% CI = 0.88-1.00].

The investigators found high dietary folate intake significantly reduced breast cancer risk in women with moderate or high levels of alcohol consumption with 18% [RR = 0.82, 95% CI = 0.72-0.94].

The investigators concluded that at least 100 μg per day dietary folate intake, reduce both oestrogen-receptor-negative and oestrogen-receptor-negative/progesterone-receptor-negative breast cancer, particularly among premenopausal women and women with moderate or high levels of alcohol consumption.

Original title:
Folate intake and the risk of breast cancer: an up-to-date meta-analysis of prospective studies by Zeng J, Wang K, [...], Chang H.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30647438

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Objectives:
Low fruit and vegetable intakes are recognized risk factors for noncommunicable diseases. Therefore, this review article has been conducted.

Do fruit or vegetables intakes reduce noncommunicable diseases, likes cancer, coronary heart disease and all-cause mortality?

Study design:
This review article included 64 reports investigating 98 risk-disease pairs. 56 pairs from 39 reports were assessed as statistically significant, involving 29 burden of diseases.

Results and conclusions:
The investigators found in linear dose analysis for each 100 g/day increase in fruit intakes a significantly reduced risk of 44% [RR = 0.56, 95% CI = 0.42 to 0.74] for esophageal cancer.
Significant means that there is an association with a 95% confidence.

The investigators found in linear dose analysis for each 100 g/day increase in fruit intakes a significantly reduced risk of 28% [RR = 0.72, 95% CI = 0.59 to 0.87] for mouth, pharynx and larynx cancer.

The investigators found in nonlinear dose analysis for the first 100 g/day increase in fruit intakes a significantly reduced risk of 14% [RR = 0.86, 95% CI = 0.84 to 0.88] for stroke.

The investigators found in nonlinear dose analysis for the first 100 g/day increase in fruit intakes a significantly reduced risk of 11% [RR = 0.89, 95% CI = 0.88 to 0.90] for all-cause mortality.

The investigators found in linear dose analysis for each 100 g/day increase in vegetable intakes a significantly reduced risk of 12% [RR = 0.88, 95% CI = 0.80 to 0.95] for renal cell cancer.

The investigators found in linear dose analysis for each 100 g/day increase in vegetable intakes a significantly reduced risk of 11% [RR = 0.89, 95% CI = 0.84 to 0.95] for non-Hodgkin lymphoma.

The investigators found in nonlinear dose analysis for the first 100 g/day increase in vegetable intakes a significantly reduced risk of 14% [RR = 0.86, 95% CI = 0.84 to 0.89] for coronary heart disease.

The investigators found in nonlinear dose analysis for the first 100 g/day increase in vegetable intakes a significantly reduced risk of 13% [RR = 0.87, 95% CI = 0.84 to 0.90] for all-cause mortality.

The investigators found in nonlinear dose analysis clear increases in protective associations were observed with the first 200 g/day of fruit or vegetable intakes, whereas little further increase or even decrease in protective associations were reported beyond 300 g/day intakes.

The investigators found canned fruit intakes were positively associated with all-cause and cardiovascular disease mortality.

The investigators found pickled vegetable intakes were positively associated with stomach cancer.

The investigators concluded that 100-300 g/day of fruit or vegetables intakes reduce certain cancers, coronary heart disease and all-cause mortality. These findings support existing recommendations for fruit and vegetable intakes. Current comparative risk assessments might significantly underestimate the protective associations of fruit and vegetable intakes.

Original title:
The Associations of Fruit and Vegetable Intakes with Burden of Diseases: A Systematic Review of Meta-Analyses by Yip CSC, Chan W and Fielding R.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30639206

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Find more information/studies on fruit and vegetable consumption, coronary heart disease and cancer right here.

Objectives:
Lung cancer is the most common cause of cancer death. Fruits and vegetables containing carotenoids and other antioxidants have been hypothesized to decrease lung cancer risk. Therefore, this meta-analysis (systematic review) has been conducted.

Do fruits and vegetables reduce lung cancer risk?

Study design:
This review article included prospective cohort studies up to December 2014.

Results and conclusions:
The investigators found in 18 studies, when comparing the highest fruits and vegetables with the lowest intakes, a significantly reduced risk of 14% for lung cancer [summary RR = 0.86 [95% CI = 0.78-0.94].

The investigators found in 25 studies, when comparing the highest vegetables with the lowest intakes, a significantly reduced risk of 8% for lung cancer [summary RR = 0.92 [95% CI = 0.87-0.97].

The investigators found in 29 studies, when comparing the highest fruits with the lowest intakes, a significantly reduced risk of 18% for lung cancer [summary RR = 0.82, 95% CI = 0.76-0.89].

The investigators found the association with fruit and vegetable intake was marginally significant in current smokers and inverse but not significant in former or never smokers.

The investigators found in 4 studies for each 100 g/day increase of fruits and vegetables, a significantly reduced risk of 4% for lung cancer [RR = 0.96, 95% CI = 0.94-0.98, I2 = 64%, n (cases) = 9,609].

The investigators found in 20 studies for each 100 g/day increase of vegetables, a significantly reduced risk of 6% for lung cancer [RR = 0.94, 95% CI = 0.89-0.98, I2 = 48%, n (cases) = 12,563].

The investigators found in 23 studies for each 100 g/day increase of fruits, a significantly reduced risk of 8% for lung cancer [RR = 0.92, 95% CI = 0.89-0.95, I2 = 57%, n (cases) = 14,506].

The investigators found the results were consistent among the different types of fruits and vegetables. However, the strength of the association differed across locations.

The investigators found evidence of a non-linear relationship [p 0.01] between fruit and vegetable intake and lung cancer risk showing that no further benefit is obtained when increasing consumption above ∼400g per day.

The investigators concluded fruits and/or vegetables intakes reduce risk of lung cancer with no further benefit when increasing consumption of fruits and vegetables above ∼400g per day.

Original title:
Fruits, vegetables and lung cancer risk: a systematic review and meta-analysis by Vieira AR, Abar L, […], Norat T.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/26371287

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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:
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:
Is there an association of intake of different vitamins and multiple-vitamin supplements and the incidence of colorectal cancer?

Study design:
This review article included 47 articles (cohort studies).

There was unacceptable heterogeneity for studies of multiple-vitamin supplements, so findings were inconclusive.

Results and conclusions:
The investigators found a significant reduced risk of 12% [multivariable-adjusted RR = 0.88, 95% CI = 0.81-0.95] for colorectal cancer when comparing the highest versus lowest dietary vitamin B9 (folate) intake. Significant means that there is an association with a 95% confidence.

The investigators found a significant reduced risk of 13% [multivariable-adjusted RR = 0.87, 95% CI = 0.77-0.99] for colorectal cancer when comparing the highest versus lowest dietary vitamin D intake. Significant because RR of 1 was not found in the 95% CI of 0.77 to 0.99. RR of 1 means no risk/association.

The investigators found a significant reduced risk of 12% [multivariable-adjusted RR = 0.88, 95% CI = 0.79-0.99] for colorectal cancer when comparing the highest versus lowest dietary vitamin B6 intake.

The investigators found a significant reduced risk of 14% [multivariable-adjusted RR = 0.86, 95% CI = 0.76-0.97] for colorectal cancer when comparing the highest versus lowest dietary vitamin B2 intake.

The investigators found, however, no association between both dietary vitamine A, C, E, B3 and B12 and the risk of colorectal cancer.

The investigators concluded high dietary vitamin B9 (folate), D, B6 and B2 intake reduces risk of colorectal cancer, but further study is needed.

Original title:
Vitamin and multiple-vitamin supplement intake and incidence of colorectal cancer: a meta-analysis of cohort studies by Liu Y, Yu Q, […], Li K.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/25491145

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Objectives:
Red meat intake has been associated with risk of colorectal cancer, potentially mediated through heterocyclic amines. The metabolic efficiency of N-acetyltransferase 2 (NAT2) required for the metabolic activation of such amines is influenced by genetic variation. The interaction between red meat intake, NAT2 genotype and colorectal cancer has been inconsistently reported. Therefore, this review article has been conducted.

Is there an interaction between red meat intake, NAT2 genotype and colorectal cancer?

Study design:
This review article included 11 retrospective case-control studies with 8,290 colorectal cancer cases and 9,115 controls (subjects without colorectal cancer).

Results and conclusions:
The investigators found the highest quartile of red meat intake was associated with a 41% increased risk of colorectal cancer compared with the lowest quartile [OR = 1.41, 95% CI = 1.29-1.55].
However, a significant association was observed only for studies with retrospective diet data, not for studies with diet prospectively assessed before cancer diagnosis.

The investigators found when combining all studies, high red meat intake was similarly associated with colorectal cancer in those with a rapid/intermediate NAT2 genotype [OR = 1.38, 95% CI = 1.20-1.59] as with a slow genotype [OR = 1.43, 95% CI = 1.28-1.61, p interaction = 0.9].

The investigators concluded high red meat intake was associated with increased risk of colorectal cancer only from retrospective case-control studies and not modified by NAT2 enzyme activity.

Original title:
Red Meat Intake, NAT2, and Risk of Colorectal Cancer: A Pooled Analysis of 11 Studies by Ananthakrishnan AN, Du M, […], Chan AT.

Link:
http://cebp.aacrjournals.org/content/cebp/24/1/198.full.pdf

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