Nutritional advice

Objectives:
Previous studies have demonstrated some associations between dietary vitamin A intake and ovarian cancer risk with an inconsistent relationship. Therefore, this review article (meta-analysis) has been conducted.

Does higher dietary intake of vitamin A reduce ovarian cancer risk?

Study design:
This review article included 10 case-control studies and 5 cohort studies, involving 4,882 cases (persons with ovarian cancer) among 443,179 participants.

There was no publication bias.

Results and conclusions:
The investigators found higher dietary vitamin A intake significantly reduced ovarian cancer risk with 18.4% [RR = 0.816, 95% CI = 0.723 to 0.920, I2 = 48.4%, p for heterogeneity = 0.019].
Sensitivity analysis showed that no single study had a potential impact on the pooled RR.

The investigators found higher dietary vitamin A intake significantly reduced ovarian cancer risk with 23.1% [RR = 0.769, 95% CI = 0.655 to 0.902] in case-controle studies.
However, this reduced risk was not significant in cohort studies.

The investigators found higher dietary vitamin A intake significantly reduced ovarian cancer risk with 17.5% [RR = 0.825, 95% CI = 0.720 to 0.946] in North American populations.

The investigators concluded that higher dietary intake of vitamin A reduces ovarian cancer risk, especially among North Americans. As some limitations existed in this analysis, large scale studies with detailed amount of dietary vitamin A intake are needed to verify the results.

Original title:
Dietary vitamin A intake and the risk of ovarian cancer: A meta-analysis by Wang Q and He C.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7138903/

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

Objectives:
Epidemiologic studies of the relationship between nitrite or nitrate consumption and risk of non-Hodgkin lymphoma (NHL) remain controversial. Therefore, this review article has been conducted.

Does dietary intake of nitrite or nitrate increase risk of non-Hodgkin lymphoma?

Study design:
This review article included 8 case-control and 4 cohort studies with a total of 8,067 cases of non-Hodgkin lymphoma that reported the correlation between nitrate or nitrite consumption and risk of non-Hodgkin lymphoma published between 1996 and 2013.

NOS scores ranged from 4 to 8 with a mean value of 6.
Information on nitrate and nitrite intake was obtained by personal interview, telephone interview or mailed questionnaires.

There was no evidence of publication bias.

Results and conclusions:
The investigators found that high levels of nitrite dietary intake was linked to a significantly elevated risk of non-Hodgkin lymphoma of 55% [OR = 1.55, 95% CI = 1.27-1.88, I2 = 41.8%, p = 0.161]. 

The investigators found, however, no connection between the risk of non-Hodgkin lymphoma and high levels of nitrate dietary intake [OR = 1.02, 95% CI = 0.94-1.10, I2 = 14.2%, p = 0.308].

The investigators found that the risk of non-Hodgkin lymphoma increased by 26% for each additional microgram of nitrite consumed in the diet per day [OR = 1.26, 95% CI = 1.09-1.42].

The investigators found data from the high-quality studies indicated that nitrite consumption was positively associated with carcinogenicity, leading to non-Hodgkin lymphoma [OR = 1.44, 95% CI = 1.17-1.77] and positively correlated with the development of diffuse large B-cell lymphoma [OR = 1.55, 95% CI = 1.07-2.26], but not other non-Hodgkin lymphoma subtypes.

The investigators found, in addition, high levels of nitrite dietary intake was linked to a significantly elevated risk of non-Hodgkin lymphoma of 50% [OR = 1.50, 95% CI = 1.15-1.95] in females.
However, this increased risk was not significant in males [OR = 0.84, 95% CI = 0.52-1.36].

The investigators concluded that nitrite dietary intake, but not that of nitrate, raises the risk of developing non-Hodgkin lymphoma, particularly diffuse large B-cell lymphoma in females. In the future, better designed prospective research studies should be conducted to confirm these findings, clarify potential biological mechanisms and instruct clinicians about non-Hodgkin lymphoma prophylaxis.

Original title:
The relationship between consumption of nitrite or nitrate and risk of non-Hodgkin lymphoma by Yu M, Li C, [...], Jin J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6969097/

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The preservative sodium nitrite fights harmful bacteria in ham, salami and other processed and cured meats and also lends them their pink coloration.
 

Objectives:
Previous studies had been published to explore the association about carbohydrate intake on esophageal cancer risk, with inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Does dietary intake of carbohydrate reduce esophageal cancer risk?

Study design:
This review article included 13 case-control studies that assessed a total of 3,033 patients.
The quality evaluation scores of each study ranged from 6 to 9 and the methodological quality was higher.

In the publication bias assessment, the results from funnel plots and Egger’s test detected no publication bias.

Results and conclusions:
The investigators found in overall analysis for the highest category versus lowest category of dietary carbohydrate a significantly reduced risk of 37.3% [summarized OR = 0.627, 95% CI = 0.505 to 0.778, I2 = 59.9%, p for heterogeneity = 0.001] for esophageal cancer.
Sensitivity analyses showed no single study had essential effect on the overall result.

The investigators found for the highest category versus lowest category of dietary carbohydrate a significantly reduced risk of 43.1% [summarized OR = 0.569, 95% CI = 0.417 to 0.777] for esophageal adenocarcinoma.

The investigators found for the highest category versus lowest category of dietary carbohydrate a significantly reduced risk of 33.5% [summarized OR = 0.665, 95% CI = 0.453 to 0.975] for esophageal squamous cell carcinoma.

The investigators found in subgroup analysis by study design that the association was significant in population-based case-control studies, but not in the hospital-based case-control studies.

The investigators concluded that dietary intake of carbohydrate may contribute to the lower development of esophageal cancer. May contribute because this review article only included case-control studies and no cohort studies. As some limitations existed in tbjs meta-analysis, large scale prospective studies with detailed type of dietary carbohydrate intake are needed to verify these results.

Original title:
Dietary carbohydrate intake and the risk of esophageal cancer: a meta-analysis by Xuan F, Li W, […], Liu C.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042123/

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The 2 main subtypes of esophageal cancer are esophageal squamous-cell carcinoma (often abbreviated to ESCC) and esophageal adenocarcinoma (EAC).
 

Objectives:
Does post-diagnosis dietary supplement use decrease total mortality, cancer mortality and recurrence among cancer survivors?

Study design:
This review article included observational studies and randomized clinical trials (RCT).

Results and conclusions:
The investigators found in 4 observational studies, compared to no supplementation, calcium supplementation significantly reduced total mortality with 12% [RR = 0.88, 95% CI = 0.77 to 1.00, I2 = 0%] among all cancer survivors.

The investigators found in 3 observational studies, compared to no supplementation, calcium supplementation significantly reduced cancer mortality with 29% [RR = 0.71, 95% CI = 0.53 to 0.95, I2 = 0%] among all cancer survivors.

The investigators found in 2 observational studies, compared to no supplementation, calcium supplementation significantly reduced cancer mortality with 34% [RR = 0.66, 95% CI = 0.47 to 0.94, I2 = 0%] among colorectal cancer survivors.

The investigators found in 2 observational studies and 2 RCT’s, compared to no supplementation, vitamin D supplementation significantly reduced total mortality with 14% [RR = 0.86, 95% CI = 0.76 to 0.99, I2 = 0%] among all cancer survivors.

The investigators found in 4 observational studies, compared to no supplementation, vitamin C supplementation significantly reduced total mortality with 21% [RR = 0.79, 95% CI = 0.68 to 0.92, I2 = 0%] among breast cancer survivors.

The investigators found in 2 observational studies, compared to no supplementation, vitamin D supplementation significantly reduced total mortality with 15% [RR = 0.85, 95% CI = 0.72 to 0.99, I2 = 0%] among breast cancer survivors.

The investigators found in 3 observational studies, compared to no supplementation, vitamin E supplementation significantly reduced total mortality with 24% [RR = 0.76, 95% CI = 0.64 tot 0.90, I2 = 0%] among breast cancer survivors.

The investigators found in 2 observational studies, compared to no supplementation, multivitamins supplementation significantly reduced cancer recurrence with 21% [RR = 0.79, 95% CI = 0.64 to 0.97, I2 = 0%] among breast cancer survivors.

The investigators found in 2 observational studies, compared to no supplementation, vitamin C supplementation significantly reduced cancer recurrence with 24% [RR = 0.76, 95% CI = 0.64 to 0.91, I2 = 0%] among breast cancer survivors.

The investigators found in 2 observational studies, compared to no supplementation, vitamin E supplementation significantly reduced cancer recurrence with 31% [RR = 0.69, 95% CI = 0.55 to 0.85, I2 = 0%] among breast cancer survivors.

The investigators concluded post-diagnosis dietary supplement use (particularly calcium, vitamin C, D and E) decreases total mortality, cancer mortality and recurrence among cancer survivors.

Original title:
Dietary Supplement Use after Cancer Diagnosis in Relation to Total Mortality, Cancer Mortality and Recurrence: A Systematic Review and Meta-Analysis by Kanellopoulou A, Riza E, […], Benetou V.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32148118

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Objectives:
Does high waist circumference increase liver cancer?

Study design:
This review article included  5 prospective cohort studies with 2,547,188 participants.
Participants were aged 46-58 years, with a mean age of 51 years.
The mean follow-up of participants in the studies was 7.8 years.
The mean quality (NOS scores) of the studies included was 7 (ranging from 5 to 9).

Funnel plots did not show significant asymmetry between the studies included.
Furthermore, Begg's and Egger's regression test did not show any significant publication bias (p = 0.62 and p = 0.60, respectively).

Results and conclusions:
The investigators found combined results of the studies included with random-effects model showed that the highest waist circumference category was significantly associated with an increased risk of 59% for liver cancer [HR = 1.59, 95% CI = 1.38-1.83, I2 = 0%, p = 0.42] compared to the lowest waist circumference category.

The investigators concluded that waist circumference is a significant risk factor related to the incidence of liver cancer.

Original title:
Waist Circumference and Risk of Liver Cancer: A Systematic Review and Meta-Analysis of over 2 Million Cohort Study Participants by Rahmani J, Kord Varkaneh H, [...], Zhang Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7024879/

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Objectives:
Epidemiologic studies have investigated the association between nut intake and risk for multiple cancers. However, current findings are inconsistent and no definite conclusion has been drawn from prospective studies. Therefore, this review article has been conducted.

Does nut consumption reduce cancer risk?

Study design:
This review article included 33 cohort studies with more than 50,000 cancer cases.

Results and conclusions:
The investigators found when comparing the highest with the lowest category of nut consumption, high consumption of nuts significantly decreased risk of overall cancer with 10% [RR = 0.90, 95% CI = 0.85-0.95].
Significant association was only obtained for intake of tree nuts.

The investigators found when comparing the highest with the lowest category of nut consumption, high consumption of nuts significantly decreased risk of cancer from the digestive system with 17% [RR = 0.83, 95% CI = 0.77-0.89].

The investigators found per 20 g/day increase in nut consumption was related to a 10% [RR = 0.90, 95% CI = 0.82-0.99] decrease in cancer risk.

The investigators concluded that consumption of 20 grams of tree nuts per day reduces cancer of the digestive system.

Original title:
Nut Consumption and Risk of Cancer: A Meta-analysis of Prospective Studies by Long J, Ji Z, […], Cheng L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32041895

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Objectives:
Which factors are associated with the risk of stomach cancer?

Study design:
This review article included 232 observational studies involving 33,831,063 participants.

Results and conclusions:
The investigators found H. pylori infection significantly increased risk of stomach cancer with 156% [OR = 2.56, 95% CI = 2.18 to 3.00].

The investigators found formerly smoked significantly increased risk of stomach cancer with 43% [OR = 1.43, 95% CI = 1.29 to 1.59].

The investigators found currently smoking significantly increased risk of stomach cancer with 61% [OR = 1.61, 95% CI = 1.49 to 1.75].

The investigators found currently drinking significantly increased risk of stomach cancer with 19% [OR = 1.19, 95% CI = 1.10 to 1.29].

The investigators found formerly drank significantly increased risk of stomach cancer with 73% [OR = 1.73, 95% CI = 1.17 to 2.56].

The investigators found intake of fruits ≥3 times/week significantly decreased risk of stomach cancer with 52% [OR = 0.48, 95% CI = 0.37 to 0.63].

The investigators found intake of vegetables ≥3 times/week significantly decreased risk of stomach cancer with 38% [OR = 0.62, 95% CI = 0.49 to 0.79].

The investigators found using pickled vegetables significantly increased risk of stomach cancer with 28% [OR = 1.28, 95% CI = 1.09 to 1.51].

The investigators found green tea significantly decreased risk of stomach cancer with 12% [OR = 0.88, 95% CI = 0.80 to 0.97].

The investigators concluded that both smoking, drinking and H. pylori infection increase the risk of stomach cancer, while both ≥3 times/week fruit and vegetables and green tea reduce the risk of developing stomach cancer.

Original title:
Risk factors for stomach cancer: a systematic review and meta-analysis by Poorolajal J, Moradi L, [...], Gohari-Ensaf F.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32023777

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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:
Does dietary intake of garlic reduce risk of colorectal cancer?

Study design:
This review article included 11 studies involving 12,558 cases (persons with colorectal cancer).

There was no notable evidence of publication bias.

Results and conclusions:
The investigators found for the highest versus the lowest garlic consumption categories, a significantly reduced risk of 20% [integrated relative risk = 0.80, 95% CI = 0.69 to 0.91] for colorectal cancer.
The sensitivity analysis revealed no notable alterations of the integrated results.
Significant means that there is an association with a 95% confidence.

The investigators found in case-control studies for the highest versus the lowest garlic consumption categories, a significantly reduced risk of 29% [relative risk = 0.71, 95% CI = 0.60 to 0.84] for colorectal cancer.
Significant because relative risk of 1 was not found in the 95% CI of 0.60 to 0.84. Relative risk of 1 means no risk/association.

The investigators found in cohort studies for the highest versus the lowest garlic consumption categories, a non-significantly reduced risk of 1% [relative risk = 0.99, 95% CI = 0.80 to 1.23] for colorectal cancer.
Non-significantly because relative risk of 1 was found in the 95% CI of 0.80 to 1.23. Relative risk of 1 means no risk/association.

The investigators concluded that dietary intake of garlic could reduce risk of colorectal cancer. Could reduce because the risk was not significant in cohort studies.

Original title:
Garlic intake and the risk of colorectal cancer: A meta-analysis by Zhou X, Qian H, […], Zeng L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31895803

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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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Find more information/studies on fat consumption and cancer right here.
 

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

Additional information of El Mondo:
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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/

Additional information of El Mondo:
Find more information/studies on coffee and tea consumption, review article/significantly and cancer right here.
 

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

Additional information of El Mondo:
Find more information/studies on coffee consumption, review article/significantly and cancer right here.
 

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

Additional information of El Mondo:
Find more information/studies on fish consumption, review article/significantly and breastcancer right here.

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

Additional information of El Mondo:
Find more information/studies on trans fatty acids consumption, review article/significantly and breastcancer right here.

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

Additional information of El Mondo:
Find more information/studies on folate consumption, review article/significantly and breast cancer right here.

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

Additional information of El Mondo:
Find more information/studies on fruit and vegetable consumption, coronary heart disease and cancer right here.

Objectives:
Epidemiological studies regarding the association between dietary fiber intake and ovarian cancer risk are still inconsistent. Therefore, this review article has been conducted.

Does dietary fiber intake reduce ovarian cancer risk?

Study design:
This review article included 10 case-control studies and 3 cohort studies, with a total of 5,777 ovarian cancer cases and 142,189 participants.

All the included studies provided RRs that were adjusted for energy intake and most provided RRs that were adjusted for age, oral contraceptive use, menopausal status and parity.
All the original studies measured dietary intakes using a food-frequency questionnaire. NOS scores ranged from 6 to 8 and 7 studies were considered high quality.

Funnel plot shapes demonstrated a symmetrical distribution and no evidence of publication bias was detected by the Egger’s regression test [p = 0.73].

Results and conclusions:
The investigators found for the highest vs. the lowest category of dietary fiber intake a significantly reduced risk of 22% [pooled multivariable RR = 0.78, 95% CI = 0.70 to 0.88, I2 = 4.20%, p = 0.40] for ovarian cancer.

The investigators found a significantly reduced risk of 12% [summarized RR = 0.88, 95% CI = 0.82 to 0.93, I2 = 7.3%, p = 0.38] for ovarian cancer per 10 g/day increase of dietary fiber intake.

The investigators found there was no evidence for a nonlinear association between dietary fiber intake and ovarian cancer risk [p for nonlinearity = 0.83].

The investigators found in subgroup analysis a significantly reduced risk of 23% [pooled RR = 0.77, 95% CI = 0.66 to 0.90] for ovarian cancer in case-control studies. However, the reduced risk was not significant in cohort studies [pooled RR = 0.84, 95% CI = 0.65 to 1.10].

The investigators found sensitivity analysis showed that none of the studies influenced the combined results substantially, with a range from 0.77 [95% CI = 0.68 to 0.87] to 0.81 [95% CI = 0.71 to 0.91].

The investigators concluded that 10g dietary fiber intake per day may reduce the risk of ovarian cancer with 12%. May reduce because the reduced risk was not significant in cohort studies.

Original title:
Dietary fiber intake and reduced risk of ovarian cancer: a meta-analysis by Zheng B, Shen H, […], Qin Y.

Link:
https://nutritionj.biomedcentral.com/articles/10.1186/s12937-018-0407-1

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Objectives:
Several B vitamins are essential in the one-carbon metabolism pathway, which is central to DNA methylation, synthesis and repair. Moreover, an imbalance in this pathway has been linked to certain types of cancers. Therefore, this review article has been conducted.

Is there a relationship between dietary vitamin intake and risk of esophageal cancer (EC)?

Study design:
This review article included 24 patient-control studies and 2 cohort studies with a total of 510,954 participants and 6,404 esophageal cancer cases, which included 1,919 esophageal adenocarcinoma (EAC) patients, 2,010 esophageal squamous cell carcinoma (ESCC) patients and 2,475 esophageal cancer (EC) patients.

The quality scores of all studies ranged from 6 to 8, with a median score of 7.

There was no significant publication bias in the final analysis with respect to vitamin B2 [p = 0.244], vitamin B6 [p = 0.068], folate [p = 0.054] or vitamin B12 [p = 0.093].

A sensitivity analysis revealed that no individual study affected the pooled effect size.

Results and conclusions:
The investigators found for the highest level versus the lowest level of dietary folate intake, a significantly reduced risk of 38% [pooled OR = 0.62, 95% CI = 0.56-0.68, I2 = 40.2%] for esophageal cancer.
Subgroup analysis revealed that this inverse correlation (reduced risk) was present in the US [OR = 0.58, 95% CI = 0.51-0.67], Europe [OR = 0.51, 95% CI = 0.40-0.65] and Australia [OR = 0.74, 95% CI = 0.58-0.95], but not in Asia [OR = 0.77, 95% CI = 0.59-1.01].

The investigators found in dose-response analysis that each 100 μg/day increase in dietary folate intake significantly reduced the risk of esophageal cancer by 12% [OR = 0.88, 95% CI = 0.86-0.91].
Significant means that there is an association with a 95% confidence.

The investigators found for the highest level versus the lowest level of dietary vitamin B6 intake, a significantly reduced risk of 41% [pooled OR = 0.59, 95% CI = 0.52-0.66, I2 = 46.8%] for esophageal cancer.
This inverse relationship remained significant in subgroup analyses for esophageal adenocarcinoma [OR = 0.58, 95% CI = 0.49-0.68] and esophageal squamous cell carcinoma [OR = 0.47, 95% CI = 0.33-0.67].

The investigators found in dose-response analysis, a significantly reduced risk of 18% [OR = 0.82, 95% CI = 0.76-0.88] for esophageal cancer for 2.0 mg/day of dietary vitamin B6 intake.

The investigators found in dose-response analysis, a significantly reduced risk of 33% [OR = 0.67, 95% CI = 0.59-0.75] for esophageal cancer for 2.5 mg/day of dietary vitamin B6 intake.

The investigators found in dose-response analysis, a significantly reduced risk of 45% [OR = 0.55, 95% CI = 0.44-0.67] for esophageal cancer for 3.0 mg/day of dietary vitamin B6 intake.

The investigators found in dose-response analysis that each 1 mg/day increase in dietary B6 increase significantly reduced the risk of esophageal cancer by 16% [OR = 0.84, 95% CI = 0.80-0.89].

The investigators found for the highest level versus the lowest level of dietary vitamin B12 intake, a significantly increased risk of 30% [pooled OR = 1.30, 95% CI = 1.05-1.62, I2 = 73.5%] for esophageal cancer.
A subgroup analysis based on geographic location revealed similar results in the US [OR = 1.26, 95% CI = 1.03-1.53] and Europe [OR = 2.54, 95% CI = 1.16-5.53], but not in Australia [OR = 0.93, 95% CI = 0.73-1.19].
A subgroup analysis based on histological type revealed that this correlation was present among patients with esophageal adenocarcinoma [OR = 1.47, 95% CI = 1.02-2.11], but not among patients with esophageal squamous cell carcinoma [OR = 1.00, 95% CI = 0.63-1.61].

The investigators found in dose-response analysis that each 1 μg/day increase in dietary B12 intake significantly increased the risk of esophageal cancer by 2% [OR = 1.02, 95% CI = 1.00-1.03].

The investigators concluded that both dietary vitamin B6 intake (at least 1 mg/day) and dietary folate intake (at least 100 μg/day) are inversely correlated with esophageal cancer risk, whereas dietary vitamin B12 intake (at least 1 μg/day) increases esophageal cancer risk.

Original title:
Intake of Dietary One-Carbon Metabolism-Related B Vitamins and the Risk of Esophageal Cancer: A Dose-Response Meta-Analysis by Qiang Y, Li Q, […], Wang F.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6073467/

Additional information of El Mondo:
Find more information/studies on folate, vitamin B6 and B12 and cancer right here.

Objectives:
Many studies were conducted to explore the relationship between dietary protein intake and risk of prostate cancer, obtaining inconsistent results. Therefore, this review article has been conducted.

Does dietary protein intake increase risk of prostate cancer?

Study design:
This review article included a total of 8 cohort studies, 5 case-control studies and 1 RCT, comprising 13,483 prostate cancer cases among 286,245 participants.

Begg’s funnel plots and Egger’s test [p = 0.296] indicated that no publication bias was found in overall analysis.

Results and conclusions:
The investigators found in the overall analysis there was no association with prostate cancer risk when comparing the highest protein intake with the lowest protein intake [summary RR = 0.993, 95% CI = 0.930-1.061, I2 = 0.0%, p = 0.656].
The sensitivity analysis showed that there is no single study that had potential effects on the overall result while removing a study at a time.

The investigators found in the stratified analysis by protein type, the association was non-significant on prostate cancer risk in both animal protein intake [RR = 1.001, 95% CI = 0.917-1.092] and vegetable protein intake [RR = 0.986, 95% CI = 0.904-1.076].
Non-significant because RR of 1 was found in the 95% CI of 0.917 to 1.092. RR of 1 means no risk/association.

The investigators found there was also no significant association in cohort studies [RR = 1.080, 95% CI = 0.964-1.209] and in case-control studies [RR = 0.960, 95% CI = 0.874-1.055].

The investigators found there was no association with prostate cancer localized-stage disease risk when comparing the highest protein intake with the lowest protein intake [summary RR = 1.263, 95% CI = 0.953-1.674].

The investigators found there was no association with prostate cancer advanced-stage disease risk when comparing the highest protein intake with the lowest protein intake [summary RR = 0.973, 95% CI = 0.745-1.272].

The investigators concluded that there is no effect on prostate cancer with high-protein intake. Since some limitations exited in this review article, future studies are wanted to confirm the result.

Original title:
Association between dietary protein intake and prostate cancer risk: evidence from a meta-analysis by Ye M, Yan T and Jing D.

Link:
https://wjso.biomedcentral.com/articles/10.1186/s12957-018-1452-0

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