Nutritional advice

Objectives:
Does consumption of fruits and vegetables reduce risk of endometrial cancer?

Study design:
This review article included  of 21 case-control studies and 6 cohort studies.

Results and conclusions:
The investigators found that vegetables consumption significantly reduced risk of endometrial cancer with 24% [pooled odds ratio [OR], relative risk [RR], hazard ratio [HR] = 0.76, 95% CI = 0.63 to 0.91].

The investigators found that cruciferous vegetables consumption significantly reduced risk of endometrial cancer with 19% [pooled OR = 0.81, 95% CI = 0.70 to 0.94].

The investigators found that dark green and yellow/orange combined vegetables consumption significantly reduced risk of endometrial cancer with 36% [pooled OR = 0.64, 95% CI = 0.42 to 0.97].

The investigators found that fruits consumption significantly reduced risk of endometrial cancer with 19% [pooled OR = 0.81, 95% CI = 0.70 to 0.92].

The investigators found these results were primarily based on studies of high quality and exhibited either by case-control only or a combination of case-control and cohort studies. Additionally, the results varied by geographic location, such as Western areas, the US and Italy.

The investigators concluded that consumption of fruits and vegetables has beneficial effects on endometrial cancer risk and that specific kinds of fruits and vegetables should be recommended differently due to their outstanding bioactive components.

Original title:
The influence of dietary vegetables and fruits on endometrial cancer risk: a meta-analysis of observational studies by Lu YT, Gunathilake M and Kim J.

Link:
https://pubmed.ncbi.nlm.nih.gov/36151331/

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

Objectives:
There is keen interest in better understanding the impacts of alpha-linolenic acid (ALA), a plant-derived n-3 fatty acid, in ameliorating the development of cancer. However, results of several prospective cohort studies present an inconsistent association between ALA intake and the incident colorectal cancer (CRC). Therefore, this review article has been conducted.

Does a high dietary intake of alpha-linolenic acid or a high level of alpha-linolenic acid in blood reduce risk of colorectal cancer (colon and rectal cancer)?

Study design:
This review article included 15 cohort studies (11 studies on diet and 5 studies on biomarkers including 4 on blood and 1 on adipose tissue) with 12,239 colorectal cancer cases occurred among 861,725 participants.
The mean follow-up was 9.3 years (ranging from 1 to 28 years).
Among all of the included studies, quality scores assessed by the 9-star NOS ranged from 7 to 9, with a median quality (≤7 stars) in 2 studies and high quality (≥ 8 stars) in 13 studies.

There was no publication bias.

Results and conclusions:
The investigators found higher level of alpha-linolenic acid in blood significantly reduced risk of colorectal cancer with 17% [summary RR = 0.83, 95% CI = 0.69 to 0.99, I2 = 0.0%].

The investigators found each 0.1% increase in the level of alpha-linolenic acid in blood was significantly associated with a 10% reduction in colorectal cancer risk [summary RR = 0.90, 95% CI = 0.80 to 0.99, I2 = 38.6%].

The investigators no significant dose-response association between dietary intake of alpha-linolenic acid and the incident colorectal cancer [p for non-linearity = 0.18; p for linearity = 0.24].

The investigators concluded that higher blood levels of alpha-linolenic acid reduce risk of colorectal cancer while higher dietary intake of alpha-linolenic acid does not reduce risk of colorectal cancer. Encouraging the consumption of foods rich in alpha-linolenic acid to improve its levels in the blood may potentially decrease the risk of colorectal cancer. Nevertheless, well-designed and large-scale cohort studies with biomarkers are still needed for better reconfirming the potential impacts of alpha-linolenic acid intake in the primary prevention of colorectal cancer.

Original title:
Association of Dietary Intake and Biomarker of α-Linolenic Acid With Incident Colorectal Cancer: A Dose-Response Meta-Analysis of Prospective Cohort Studies by Dai ZB, Ren XL, […], Xu L.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9301188/

Additional information of El Mondo:
Find more information/studies on colorectal cancer and alpha-linolenic acid consumption right here.

Objectives:
Colorectal cancer is one of the most commonly diagnosed and deadly cancers worldwide. Epidemiological studies on the relationship between folate intake and the risk of colorectal cancer have reported inconsistent findings since folate fortification in the USA. Therefore, this review article has been conducted.

Does a high folate (folic acid) ietary intake reduce risk of colorectal cancer (colon and rectal cancer)?

Study design:
This review article included 24 cohort studies involving 6,165,894 individuals, of which 37,280 persons with colorectal cancer.

Results and conclusions:
The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer with 12% [combined relative risk (RR) = 0.88, 95% CI = 0.83 to 0.92, p = 0.0004].
Significantly means that there is an association with a 95% confidence.

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer with 3% among persons witih medium alcohol consumption [RR = 0.97, 95% CI = 0.96 to 0.99, p = 0.008].
Significantly because RR of 1 was not found in the 95% CI of 0.96 to 0.99. RR of 1 means no risk/association.

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer with 5% among persons witih high alcohol consumption [RR = 0.95, 95% CI = 0.92 to 0.97, p = 0.003].

The investigators found compared with the lowest dietary intake, the highest folate dietary intake did not reduce risk of colorectal cancer among non-drinkers [RR = 1.00, 95% CI = 0.98 to 1.02, p = 0.827].

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colon cancer with 14% [RR = 0.86, 95% CI = 0.81 to 0.92, p = 0.0004].
Significantly because the calculated p-value of 0.0004 was less than the p-value of 0.05.

The investigators found compared with the lowest dietary intake, the highest folate dietary intake did not reduce risk of rectal cancer [RR = 0.92, 95% CI = 0.84 to 1.02, p = 0.112].

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer in USA and Europe but not in other regions.

The investigators concluded that high folate dietary intake reduces risk of colon cancer, particularly in people with medium or high alcohol consumption, but it still needs to be further confirmed.

Original title:
Folate intake and risk of colorectal cancer: a systematic review and up-to-date meta-analysis of prospective studies by Fu H, He J, […], Chang H.

Link:
https://pubmed.ncbi.nlm.nih.gov/35579178/

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

Colorectal cancer starts in the colon or the rectum. These cancers can also be called colon cancer or rectal cancer, depending on where they start.

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

Does a higher dietary intake of meat increases the risk of hepatocellular carcinoma?

Study design:
This review article included 17 observational studies involving 2,915,680 participants, of which 4,953 cases of hepatocellular carcinoma.

10 studies reported red meat intake, 9 reported white meat intake, 9 reported fish intake, 7 reported processed meat intake and 5 reported total meat intake.

Results and conclusions:
The investigators found results showed that the consumption of red meat [relative risk = 1.04, 95% CI = 0.91 to 1.18, I2 = 50.50%, p = 0.033] and total meat intake [relative risk = 1.01, 95% CI =  0.90 to 1.13, I2 = 15.50%, p = 0.316] were not significantly associated with risk of hepatocellular carcinoma.

The investigators found, however, a higher dietary intake of processed meat significantly increased the risk of hepatocellular carcinoma with 20% [relative risk = 1.20, 95% CI = 1.02 to 1.41, I2 = 26.30%, p = 0.228].
Significant because relative risk of 1 was not found in the 95% CI of 1.02 to 1.41. Relative risk of 1 means no risk/association.

The investigators found, in contrast, a higher dietary intake of white meat significantly decreased the risk of hepatocellular carcinoma with 24% [relative risk = 0.76, 95% CI = 0.63 to 0.92, I2 = 68.30%, p = 0.001].

The investigators found, in contrast, a higher dietary intake of fish significantly decreased the risk of hepatocellular carcinoma with 9% [relative risk = 0.91, 95% CI = 0.86 to 0.96, I2 = 40.90%, p = 0.095].

The investigators concluded that a higher dietary intake of processed meat increases the risk of hepatocellular carcinoma, while a higher dietary intake of both white meat and fish decrease the risk of hepatocellular carcinoma. Therefore, these findings suggest that dietary intervention may be an effective approach to preventing hepatocellular carcinoma. These need to be verified with further well-designed observational studies and experimental clinical research.  

Original title:
Meat Intake and the Risk of Hepatocellular Carcinoma: A Meta-Analysis of Observational Studies by Yu J, Liu Z, […], Chen W.

Link:
https://pubmed.ncbi.nlm.nih.gov/35583453/

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

Processed meats are meats that have been preserved by smoking or salting, curing or adding chemical preservatives. They include deli meats, bacon and hot dogs.

Objectives:
Evidence associating diet with the incidence of renal cell carcinoma (RCC) is inconclusive. Therefore, this umbrella review article has been conducted.

What is the association between diet and renal cell carcinoma incidence?

Study design:
This umbrella review article included 22 meta-analyses with a total of 502 individual studies and 64 summary hazard ratios (HRs) for renal cell carcinoma incidence: dietary patterns or dietary quality indices (n = 6), foods (n = 13), beverages (n = 4), alcohol (n = 7), macronutrients (n =15) and micronutrients (n =19).

No meta-analyses had high methodological quality.

59% of these 502 individual studies were cohort studies (n = 298), 39% were case-control studies (n = 196) and 2% were pooled studies (n = 8).

Sixty (94%) exposures in the included meta-analyses had more than 1,000 cases or 20,000 participants.

Results and conclusions:
The investigators found no dietary factors showed convincing or highly suggestive evidence of association with renal cell carcinoma incidence in the overall analysis.

The investigators found in the overall analysis that dietary intake of vegetables significantly reduced risk of renal cell carcinoma with 26% [summary HR = 0.74, 95% = 0.63 to 0.86, suggestive evidence].

The investigators found in the overall analysis that dietary intake of vitamin C significantly reduced risk of renal cell carcinoma with 23% [summary HR = 0.77, 95% = 0.66 to 0.90, suggestive evidence].

The investigators found in the overall analysis that moderate drinking significantly reduced risk of renal cell carcinoma with 23% [summary HR = 0.77, 95% = 0.70 to 0.84, convincing evidence] in Europe and North America.

The investigators found in the overall analysis that dietary intake cruciferous vegetables significantly reduced risk of renal cell carcinoma with 22% [summary HR = 0.78, 95% = 0.70 to 0.86, highly suggestive evidence] in North America.

The investigators concluded dietary intake of vegetables and vitamin C could reduce renal cell carcinoma risk. Moderate drinking might be beneficial for Europeans and North Americans and cruciferous vegetables might be beneficial to North Americans, but the results should be interpreted with caution because no meta-analyses had high methodological quality. More researches are needed in the future.

Original title:
The role of diet in renal cell carcinoma incidence: an umbrella review of meta-analyses of observational studies by Liao Z, Fang Z, […], Luo Z.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8812002/

Additional information of El Mondo:
Find more information/studies on cancer, vegetables, vitamin C right here.

An umbrella review article is a scientific article which only includes meta-analyses (also called review articles). The results found in an umbrella review article are more reliable than found in an individual review article.

One swallow does not make a summer. A famous Dutch saying that could not be any more obvious. Just because one single scientific study about a certain topic makes certain claims, it does not necessarily mean it is true. On the other hand, a review article (a collection of scientific studies on a certain topic) of randomized, placebo-controlled double blind clinical trials (RCTs) will answer the following question:
"Do taking dietary supplements make sense?" Yes for a positive conclusion and no for a negative conclusion.

One swallow does not make a summer. A famous Dutch saying that could not be any more obvious. Just because one single scientific study about a certain topic makes certain claims, it does not necessarily mean it is true. On the other hand, a review article (a collection of scientific studies on a certain topic) of (prospective) cohort studies or case-control studies will answer the following question:
"Should I change my diet?".

Objectives:
Does a high olive oil consumption reduce cancer risk?

Study design:
This review article included 37 case-control studies with 17,369 cases (persons with cancer) and 28,294 controls (persons without cancer) and 8 cohort studies with 12,461 incident cases among 929,771 subjects (participants).

Significant publication bias was detected via Egger’s test in the analysis on overall cancer risk [p 0.001], breast cancer [p = 0.013] and gastrointestinal cancer risk [p = 0.048].

Results and conclusions:
The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 31% lower risk of any cancer [pooled RR = 0.69, 95% CI = 0.62 to 0.77].  
Significantly means that there is an association with a 95% confidence.

The investigators found subgroup analyses showed that the protective effect of high olive oil consumption in terms of cancer risk was also significant in case-control studies [37 study arms, RR = 0.65, 95% CI = 0.57 to 0.74] but not in cohort studies [8 study arms, RR = 0.90, 95% CI = 0.77 to 1.05].
Furthermore, the protective association was also found in a multivariate analysis [32 study arms, RR = 0.72, 95% CI = 0.65 to 0.81], a high study quality analysis [RR = 0.72, 95% CI = 0.64 to 0.81], Mediterranean participants [RR = 0.69, 95% CI = 0.60 to 0.79] and non-Mediterranean participants [RR = 0.49, 95% CI = 0.34 to 0.71].

The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 33% lower risk of breast cancer [pooled RR = 0.67, 95% CI = 0.52 to 0.86].  
Significantly because RR of 1 was not found in the 95% CI of 0.52 to 0.86. RR of 1 means no risk/association.

The investigators found subgroup analyses showed that the beneficial effect was reproducible in case-control studies [RR = 0.63, 95% CI = 0.45 to 0.87] but not in cohort studies.
Furthermore, high olive oil consumption was linked to a reduced breast cancer risk in Mediterranean [RR = 0.67, 95% CI = 0.49 to 0.92] and non-Mediterranean populations [RR = 0.25, 95% CI = 0.07 to 0.89].

The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 23% lower risk of gastrointestinal cancer [pooled RR = 0.77, 95% CI = 0.66 to 0.89].  
Subgroup analyses showed an inverse relationship between highest olive oil consumption and risk for esophageal cancer [RR = 0.47, 95%CI = 0.24 to 0.93] and pancreatic cancer [RR = 0.58, 95% CI = 0.35 to 0.97].
Furthermore, significant effects were also found in case-control studies [RR = 0.72, 95% CI = 0.61 to 0.85), studies within the Mediterranean area [RR = 0.77, 95% CI = 0.67 to 0.88], multivariate analyses [RR = 0.76, 95% CI = 0.63 to 0.90] and high quality studies [RR = 0.73, 95% CI = 0.62 to 0.86].

The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 26% lower risk of upper aerodigestive cancer [pooled RR = 0.74, 95% CI = 0.60 to 0.91].  
Subgroup analyses showed results remained significant for case-control studies [RR = 0.74, 95% CI = 0.60 to 0.91], multivariate analyses [RR = 0.75, 95% CI = 0.66 to 0.86] and studies of high quality [RR = 0.68, 95% CI = 0.52 to 0.89].

The investigators found in pooled analysis of case-control studies that highest olive oil consumption was significantly associated with a 54% lower risk of urinary tract cancer [pooled RR = 0.46, 95% CI = 0.29 to 0.72].  
Subgroup analyses showed results remained significant for studies of high quality [RR = 0.46, 95% CI = 0.32 to 0.66].

The investigators concluded highest versus lowest olive oil consumption is associated with 31% lower cancer risk, especially for breast, overall gastrointestinal, upper aerodigestive and urinary tract cancer. Additional prospective cohort studies on various cancer types, especially in non-Mediterranean regions, as well as large randomized trials, seem desirable in order to provide further insight into the role of olive oil in preventing cancer.

Original title:
Olive oil intake and cancer risk: A systematic review and meta-analysis by Markellos C, Ourailidou ME, […], Psaltopoulout T.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8751986/

Additional information of El Mondo:
Find more information/studies on cancer, olive oil consumption right here.

The conclusions in scientific studies are even more reliable when they are also found in cohort studies, multivariate analyzes (studies where adjustments were made for multiple confounding factors) and high-quality studies.
 

Objectives:
Does postoperative coffee or caffeine consumption causally reduce risk of postoperative ileus (POI) in patients undergoing elective colorectal surgery?

Study design:
This review article included 4 RCTs with 312 subjects.

Results and conclusions:
The investigators found postoperative coffee or caffeine consumption significantly decreased the time to first bowel movement [MD = -10.36 h, 95% CI = -14.61 to -6.11], shortened the length of hospital stay [MD = -0.95 days, 95% CI = -1.57 to -0.34] and was significantly  associated with a 36%-decreased risk of the use of any laxatives after the procedure [RR = 0.64, 95% CI = 0.44 to 0.92].

The investigators found the time to first flatus, time to tolerance of solid food, risk of any postoperative complication, postoperative reinsertion of a nasogastric (NG) tube and anastomotic leakage showed no statistical differences between groups.

The investigators concluded postoperative coffee or caffeine consumption causally improves bowel movement and decreases the duration of hospital stay in patients undergoing elective colorectal surgery. This method is safe and can prevent or treat postoperative ileus (POI).

Original title:
The effect of coffee/caffeine on postoperative ileus following elective colorectal surgery: a meta-analysis of randomized controlled trials by Yang TW, Wang CT, […], Tsai MC.

Link:
https://pubmed.ncbi.nlm.nih.gov/34993568/

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

Postoperative ileus is a prolonged absence of bowel function after surgical procedures, usually abdominal surgery.

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

Additional information of El Mondo:
Find more information/studies on meta-analysis/cohort studies, fiber intake and cancer right here.

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

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

Objectives:
There has been accumulating evidence that several micronutrients may play a protective role in the risk of solid cancers. However, their role in hematological malignancies remains to be elucidated. Therefore, this review article has been conducted.

Is there a relationship between vitamin intake and risk of non-Hodgkin lymphoma?

Study design:
This review article included a total of 12 cohort studies.

Results and conclusions:
The investigators found null associations regarding
-supplemented vitamin A [pooled RR = 0.92, 95% CI = 0.80-1.07];
-supplemented vitamin C [pooled RR = 1.00, 95% CI = 0.90-1.12];
-total vitamin D [pooled RR = 1.05, 95% CI = 0.91-1.20];
-supplemented vitamin E [pooled RR = 0.98, 95% CI = 0.88-1.10] and;
-dietary lycopene intake [pooled RR = 1.00, 95% CI = 0.86-1.16] and risk of non-Hodgkin lymphoma.

The investigators found no summary estimates were provided for other hematological malignancies due to the limited number of studies.

The investigators concluded there is no association between vitamin A, C, D, E and lycopene and risk of non-Hodgkin lymphoma.

Original title:
Micronutrient Intake and Risk of Hematological Malignancies in Adults: A Systematic Review and Meta-analysis of Cohort Studies by Psaltopoulou T, Ntanasis-Stathopoulos I, […], Sergentanis TN.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30288994

Additional information of El Mondo:
Find more information/studies on vitamin A, C, D, E and lycopene right here.

Objectives:
There were inconsistent results with respect to the correlation between consumption of wine and the development of colorectal cancer (CRC). Therefore, this review article has been conducted.

Does consumption of wine increase colorectal cancer risk?

Study design:
This review article included a total of 8 case-control studies and 9 cohort studies, involving 12,110 colorectal cancer cases.

Results and conclusions:
The investigators found that wine drinking was not associated with any greater risk for colorectal cancer [SRR = 0.99, 95% CI = 0.89-1.10, p-heterogeneity 0.001] compared with nondrinkers.

The investigators found subgroup analyses (to get more information) indicated that null associations were observed in men and women for colon and rectal cancer.

The investigators found subgroup analyses showed neither light to moderate [2 drinks/day: SRR = 0.93, 95% CI = 0.80-1.08, I2 = 69.2%] nor heavy [≥2 drinks/day: SRR = 1.00, 95% CI = 0.86-1.16, I2 = 39.9%] consumption of wine was associated statistically with colorectal cancer risk.

The investigators concluded that wine consumption is not associated with the risk of colorectal cancer. Furthermore, null associations are found in men and women for colon and rectal cancer.

Original title:
Wine consumption and colorectal cancer risk: a meta-analysis of observational studies by Xu W, Fan H, [...], Ge Z.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30247171

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Objectives:
Does dietary carrot intake reduce breast cancer risk?

Study design:
This review article included a total of 10 articles involving 13,747 cases (women with breast cancer).

A significant heterogeneity was observed among studies.

Results and conclusions:
The investigators found for the highest compared with the lowest dietary carrot intake a significantly reduced risk of 21% for breast cancer [OR = 0.79, 95% CI = 0.68 to 0.90]. Omission of any single study (=sensitivity analysis) had little effect on the combined risk estimate.

The investigators found in the subgroup analyses separated by study design, the inverse associations were more pronounced in the case-control studies than in the cohort studies, while the associations did not significantly differ by geographical region, study quality, exposure assessment.

The investigators concluded that high intake of dietary carrot reduces breast cancer risk.

Original title:
Association between dietary carrot intake and breast cancer: A meta-analysis by Chen H, Shao F, […], Miao Q.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30212943

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Objectives:
Do dietary flavonoid intake reduce colorectal cancer risk?

Study design:
This review article included 5 prospective cohort and 7 case-control studies with a tolal of 17,481 cases (persons with colorectal cancer) and 740,859 controls (persons without colorectal cancer).

All studies were adjusted for a wide range of potential confounders of colorectal cancer, such as age, gender, BMI, physical activity, family history of colorectal cancer, education, energy intake, alcohol, fiber intake, red and processed meat intake, tobacco, aspirin and non-steroidal anti-inflammatory drug.

There was no publication bias.

Results and conclusions:
The investigators found that there was no significant association between colorectal cancer risk and total flavonoid intake, with a pooled OR from the combination of the included studies of 0.73 [95% CI = 0.48-1.10] for the highest category of intake vs. the lowest category. Similarly, no association between the intake of flavanones or flavan-3-ols and the risk of colorectal cancer was observed.

The investigators found in subgroup analysis of both cohort and case-control studies that when compared with the lowest, the highest intake of dietary flavonols significanty reduced risk of colorectal cancer with 30% [OR = 0.70, 95% CI = 0.54-0.90]. Nevertheless, substantial heterogeneities existed across the studies.
However, this reduced risk was not significant in cohort studies [pooled RR = 1.00, 95% CI = 0.92-1.08].

The investigators found in subgroup analysis of both cohort and case-control studies that when compared with the lowest, the highest intake of dietary flavones significanty reduced risk of colorectal cancer with 21% [OR = 0.79, 95% CI = 0.83-0.99]. Nevertheless, substantial heterogeneities existed across the studies.
However, this reduced risk was not significant in cohort studies [pooled RR = 1.02, 95% CI = 0.94-1.11].

The investigators found in subgroup analysis of both cohort and case-control studies that when compared with the lowest, the highest intake of dietary anthocyanidins significanty reduced risk of colorectal cancer with 22% [OR = 0.78, 95% CI = 0.64-0.95]. Nevertheless, substantial heterogeneities existed across the studies. 
However, this reduced risk was not significant in cohort studies [pooled RR = 1.00, 95% CI = 0.91-1.10].

The investigators found dose-response meta-analysis indicated that an increment of dietary flavones intake of 1 mg per day significantly reduced risk of colorectal cancer with 9% [pooled OR = 0.91, 95% CI = 0.84-0.99].

The investigators found dose-response meta-analysis indicated that an increment of dietary flavonols intake of 10 mg per day significantly reduced risk of colorectal cancer with 14% [pooled OR = 0.86, 95% CI = 0.76-0.97].

The investigators found that high intake of flavonols significantly decreased risk of colon cancer with 20% [OR = 0.80, 95% CI = 0.68-0.94].
Significantly means that there is an association with a 95% confidence.

The investigators found that high intake of flavones significantly decreased risk of rectal cancer with 18% [OR = 0.82, 95% CI = 0.70-0.97].
Significantly because OR of 1 was not found in the 95% CI of 0.70 to 0.97. OR of 1 means no risk/association.

The investigators concluded that high intake of dietary flavonols, flavones and anthocyanidins may decrease the risk of colorectal cancer. May decrease because substantial heterogeneities existed across the studies and the reduced risk was not significant in cohort studies.

Original title:
Dietary Flavonoids and the Risk of Colorectal Cancer: An Updated Meta-Analysis of Epidemiological Studies by Chang H, Lin Lei L, […], Guohua Zhao G.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6073812/

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The results of a review article are only reliable when they are also found in cohort studies. Thus, the significantly reduced risk must be found in both patient-control studies (more sensitive to errors) and cohort studies (less susceptible to errors).

Objectives:
Controversial results have been reported concerning the influence of calcium intake on prostate cancer risk. Therefore, this review article has been conducted.

Does calcium intake increase prostate cancer risk?

Study design:
This review article included 11 cohort studies and 1 case control study.

The average age of majority was between 50-70 years and also about 83%of articles had been performed in the USA.

Begg’s test showed the effect of publication bias was significant for relationship between calcium intake and total prostate cancer [p = 0.02] and the relationship between total calcium and localized prostate cancer [p = 0.03].

Results and conclusions:
The investigators found that total calcium intake significantly increased the total prostate cancer risk with 15% [overall RR = 1.15, 95% CI = 1.04-1.27, I2 = 59.7%, p = 0.006].
Sensitivity analysis by removing one study at the same time indicated that the overall RR was robust.

The investigators found in studies with follow-up more than 10 years a significantly increased risk of 22% [RR = 1.22, 95% CI = 1.07-1.38] for total prostate for total calcium intake.

The investigators found in 9 studies a significantly increased risk of 9% [RR = 1.09, 95% CI = 1.01-1.18] for total prostate cancer for 750 mg calcium intake per day.

The investigators found in 8 cohort studies, no association between total calcium intake and localized prostate cancer [RR = 1.05, 95% CI = 0.96-1.14].

The investigators found in 7 cohort studies, no association between total calcium intake and advance prostate cancer [RR = 1.15, 95% CI = 0.89-1.50].

The investigators concluded that calcium intake of 750 mg per day could be considered as a risk factor for total prostate cancer. Could be because there was publication bias.

Original title:
Total Calcium (Dietary and Supplementary) Intake and Prostate Cancer: a Systematic Review and Meta-Analysis by Rahmati S, Azami M, […], Sayehmiri K.

Link:
http://journal.waocp.org/?sid=Entrez:PubMed&id=pmid:29936714&key=2018.19.6.1449

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Objectives:
Prostate cancer (PCa) is one of the leading cause cancer among men worldwide. Many epidemiologic studies have reported an association between carbohydrate intake and prostate cancer. However, the evidence from epidemiologic studies is inconsistent. Therefore, this review article has been conducted.

Does carbodydrate intake increase prostate cancer risk?

Study design:
This review article included 21 studies published from 1980 to 2018, including 98,739 participants and 11,573 cases (persons with prostate cancer).

Multivariate-adjusted odds ratios (ORs) were pooled using random-effect models.

Results and conclusions:
The investigators found no association between higher carbohydrate intake and prostate cancer risk [OR =1.11, 95% CI = 0.98-1.26, I2 = 62.7%].
No association because OR of 1 was found in the 95% CI of 0.98 to 1.26. RR of 1 means no risk/association.

The investigators found no association between higher carbohydrate intake and advanced prostate cancer risk [OR = 0.95, 95% CI = 0.78-1.16, I2 = 14.1%].

The investigators found no association between higher carbohydrate intake and non-advanced prostate cancer risk [OR = 1.01, 95% CI = 0.79-1.29, I2 = 64.4%].

The investigators found there was not a significant dose-response association observed for carbohydrate intake with prostate cancer risk and advanced prostate cancer risk.

The investigators concluded that there is no association between carbohydrate intake and prostate cancer risk. Nor is association detected about carbohydrate intake with advanced or non-advanced prostate cancer risk. More studies are needed for a further dose-response meta-analysis.

Original title:
Carbohydrate intake and the risk of prostate cancer by Fan LL, Su HX, […], Nan CJ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29778541

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Objectives:
Several epidemiological studies have assessed the ability of vitamin B2 to prevent colorectal cancer (CRC), but the results are controversial. Therefore, this review article has been conducted.

Does vitamin B2 intake reduce colorectal cancer risk?

Study design:
This review article included a total of 14 studies reporting vitamin B2 intake and 2 studies reporting blood vitamin B2 concentration, comprising 14,934 cases (persons with colorectal cancer) and 1,593 cases (persons with colorectal cancer), respectively.

Results and conclusions:
The investigators found in pooled analysis a significantly reduced risk of 13% [RR = 0.87, 95% CI = 0.81-0.93] for colorectal cancer for vitamin B2 intake.
Significant means that there is an association with a 95% confidence.

The investigators found in subgroup analysis a significantly reduced risk of 14% [RR = 0.86, 95% CI = 0.78-0.94] for colorectal cancer for vitamin B2 intake from diet and supplements.

The investigators found in subgroup analysis a significantly reduced risk of 11% [RR = 0.89, 95% CI = 0.82-0.98] for colorectal cancer for dietary vitamin B2 intake.

The investigators found the dose-response model indicated a non-linear trend and colorectal cancer risk was reduced by 10% when vitamin B2 intake increased to 5 mg/day.

The investigators found that high blood concentrations of vitamin B2 significantly reduced the colorectal cancer risk with 26% [RR = 0.74, 95% CI = 0.59-0.92].

The investigators concluded that both higher vitamin B2 intake (5 mg per dag) and higher blood vitamin B2 concentration reduce colorectal cancer risk. These results suggest the importance of vitamin B2 intake in the prevention of colorectal cancer.

Original title:
Vitamin B2 intake reduces the risk for colorectal cancer: a dose-response analysis by Ben S, Du M, [...], Wang M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29744609

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Objectives:
Is there an association between wine consumption and prostate cancer risk?

Study design:
This review article included 6 cohort and 8 case-control studies with a total of 455,413 subjects regarding moderate wine consumption and risk of prostate cancer.

There was no evidence of publication bias.

Results and conclusions:
The investigators found in pooled analysis of cohort studies (438,302 subjects from which 19,238 developed prostate cancer during observation/follow-up) no association between moderate wine consumption and prostate cancer risk [pooled RR = 1.06, 95% CI = 0.96-1.15, p = 0.22, I2 = 0%]. 

The investigators found in multivariable analysis that moderate red wine consumption was associated with a significantly decreased risk of 12% for prostate cancer [pooled RR = 0.88, 95% CI = 0.78-0.999, p = 0.047, I2 = 0%]. 

The investigators found in multivariable analysis that moderate white wine consumption increased significantly the risk of prostate cancer with 26% [pooled RR = 1.26, 95% CI = 1.10-1.43, p = 0.001, I2 = 34.4%].

The investigators concluded that moderate consumption of white wine increases the risk of prostate cancer, whereas moderate consumption of red wine has a protective role. This hypothesis-generating data should serve as a rationale for uncovering the molecular underpinnings of this differential effect in order to potentially devise prevention strategies in the at-risk population.

Original title:
The impact of moderate wine consumption on the risk of developing prostate cancer by Vartolomei MD, Kimura S, […], Shariat SF.
 
Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5909789/

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Objectives:
Esophageal cancer (EC) is the eighth most common cancer and the sixth most frequent cause of cancer death in the whole world. Many studies have investigated the association between citrus fruit intake and the risk of esophageal cancer, but the results are inconsistent and not analyzed by category. Therefore, this review article has been conducted.

Does citrus fruit intake reduce esophageal cancer risk?

Study design:
This review article included 20 case-control studies and 5 cohort studies.
The studies were published between 1983 and 2015 with a total of 2,456 esophageal squamous cell carcinoma (ESCC) (range 47-395), 1,284 esophageal adenocarcinoma (EAC) (range 67-282) and 1,990 esophageal cancer (EC) (range 53-1,246).

The Newcastle-Ottawa Quality Assessment Scale (NOS) scores of 25 clinical trials range from 5 to 9, with an average of approximately 7. The median score was 6.75 for case-control studies and 8 for cohort studies.

There was no evidence of publication bias. 

Results and conclusions:
The investigators found in 10 case-control studies and 3 cohort studies a significantly reduced risk of 41% [pooled RR = 0.59, 95% CI = 0.47-0.76, I2 = 60.7%, p  = 0 .002] for esophageal squamous cell carcinoma in the citrus fruit consumption group.
Significant because RR of 1 was not found in the 95% CI of 0.47 to 0.76. RR of 1 means no risk/association.

The investigators found in 5 case-control studies and 3 cohort studies a non-significantly reduced risk of 14% [pooled RR = 0.86, 95% CI = 0.74-1.01, I2 = 0.0%, p = 0.598] for esophageal adenocarcinoma in the citrus fruit consumption group.
Non-significantly because RR of 1 was found in the 95% CI of 0.74 to 1.01. RR of 1 means no risk/association.

The investigators found in 20 case-control studies and 5 cohort studies a significantly reduced risk of 35% [pooled RR = 0.65, 95% CI = 0.56-0.75, I2 = 51.1%, p = 0.001] for esophageal cancer in the citrus fruit consumption group.

The investigators found in subgroup analysis significant inverse associations between citrus fruit intake and the risk of esophageal squamous cell carcinoma in cohort studies [OR  =  0.66, 95% CI = 0.49-0.88] and hospital-based cohort studies [OR  =  0.82, 95% CI = 0.33-0.75], but not in population-based cohort studies [OR  =  0.82, 95% CI = 0.62-1.09].

The investigators found in subgroup analysis significant inverse associations between citrus fruit intake and the risk of esophageal squamous cell carcinoma in >7 scores studies [OR =  0.56, 95% CI = 0.43-0.72].

The investigators concluded that citrus fruit intake reduces risk of esophageal cancer, particularly esophageal squamous cell carcinoma. However, further studies are warranted to find which constituents in citrus fruit prevent esophageal cancer and its mechanism.

Original title:
Intakes of citrus fruit and risk of esophageal cancer: A meta-analysis by Zhao W, Liu L and Xu S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5895383/

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Objectives:
The relationship between vitamin intake and pancreatic cancer (PC) risk is disputed. Therefore, this review article has been conducted.

Is there a relationship between dietary vitamin intake and pancreatic cancer risk?

Study design:
This review article included 25 observational studies with a total of 1,214,995 individuals, of which 8,000 pancreatic cancer cases.

In the identified studies, 10 were population-based case-control studies, 4 were hospital-based case-control studies, 2 were RCTs, 9 were cohort studies, 11 were prospective studies and 14 were retrospective studies.
The number of participants ranged from 305 to 537,218 and pancreatic cancer cases ranged from 79 to 2,383.
Quality scores of included case-control and cohort studies ranged from 7 to 9 with an average score of about 8.

Results and conclusions:
The investigators found in prospective cohort studies a significantly reduced risk of 10% [multivariable-adjusted RR = 0.90, 95% CI = 0.83-0.98, I2 = 11%] for pancreatic cancer when comparing the highest dietary vitamin intake with the lowest, particularly for 10 μg/d dietary intake of vitamin D [multivariable-adjusted RR = 0.75, 95% BI = 0.60-0.93, I2  =  59%].

The investigators concluded that a high dietary vitamin intake decreases the risk of pancreatic cancer, particularly for 10 μg/d dietary intake of vitamin D.

Original title:
Vitamin intake and pancreatic cancer risk reduction: A meta-analysis of observational studies by Liu Y, Wang X, [...], Liu S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5895396/

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A review article (a collection of scientific studies on a specific topic) of cohort studies or case-control studies will answer the following question:
"Should I change my diet?".

Objectives:
Breast cancer is the most common cancer in women worldwide. The association between body mass index (BMI) and breast cancer risk has been paid more attention in the past few years, but the findings are still controversial. Therefore, this review article has been conducted.

Is there a relationship between BMI and breast cancer risk among women?

Study design:
This review article included 12 prospective cohort studies comprising 22,728,674 women.

All studies were published from 2004 to 2014, with the mean duration of follow-up varying from 4.29 to 10.8 years.
The sample size of included studies ranged from 15,054 to 1,222,630 women.
The Newcastle-Ottawa scale was applied to assess the quality of the included studies and the results showed all studies were of high quality, with a Newcastle-Ottawa scale score of ≥7.
There was no evidence of publication bias with Egger’s test [p = 0.74] and the funnel plot showed no sign of asymmetry by visual inspection.

Results and conclusions:
The investigators found overall results showed a weak positive association between a 5-unit increase in BMI and breast cancer risk, indicating that a 5 kg/m2 increase in BMI corresponded to a 2% increase in breast cancer risk [SRR = 1.02, 95% CI = 1.01-1.04, p 0.001, I2 = 74.2%, p = 0.00]. The results were statistically robust in sensitivity analyses.

The investigators found in subgroup analysis that higher BMI significantly reduced breast cancer risk with 2% among premenopausal women [SRR = 0.98, 95% CI = 0.96-0.99, p 0.001].

The investigators found there was evidence of a linear association between BMI and breast cancer risk in both premenopausal and postmenopausal women [p nonlinearity = 0.892 and p nonlinearity = 0.630, respectively].

The investigators concluded that every 5 kg/m² increase in BMI corresponds to a 2% increase in breast cancer risk in women. However, higher BMI is a protective factor of breast cancer risk for premenopausal women. Further studies are necessary to verify these findings and elucidate the pathogenic mechanisms.

Original title:
Association between body mass index and breast cancer risk: evidence based on a dose-response meta-analysis by Liu K, Zhang W, [...], Dai Z.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5783020/

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Objectives:
Multiple epidemiologic studies have evaluated the relationship between dietary cholesterol and lung cancer risk, but the association is controversial and inconclusive. Therefore, this review article has been conducted.

Does consumption of dietary cholesterol increase risk of lung cancer?

Study design:
This review article included 10 case-control studies (6,894 lung cancer cases and 29,736 controls/persons with no lung cancer) and 6 cohort studies (1,769 lung cancer cases among 241,920 participants).

The Newcastle-Ottawa Scale scores for the included studies ranged from 6 to 9 and all studies were deemed to be of high quality (≥6).

There was no evidence of publication bias observed. Case-control studies: Egger’s test, p = 0.737, Begg’s test, p = 0.213 and cohort studies: Egger’s test, p = 0.459, Begg’s test, p = 1.000.

Results and conclusions:
The investigators found in case-control studies that a high dietary cholesterol intake significantly increased lung cancer risk with 70% [OR = 1.70, 95% CI = 1.43-2.03, I2 = 42.3%, p = 0.067]. No significant change in the result was found in the sensitivity analysis.

The investigators found in cohort studies no association between a high dietary cholesterol intake and lung cancer risk [RR = 1.08, 95% CI = 0.94-1.25, I2 = 0.0%, p = 0.833]. No significant change in the result was found in the sensitivity analysis.

The investigators found in 6 case-control studies that a high dietary total fat intake significantly increased lung cancer risk with 64% [OR = 1.64, 95% BI = 1.16-2.33, I2 = 68.7%, p = 0.004]. No significant change in the result was found in the sensitivity analysis.

The investigators concluded that a high dietary cholesterol intake might increase lung cancer risk. Might increase because the increased risk was not significant in cohort studies. Therefore, carefully designed and well-conducted cohort studies are needed to identify the association between dietary cholesterol and lung cancer risk.

Original title:
Dietary Cholesterol Intake and Risk of Lung Cancer: A Meta-Analysis by Lin X, Liu L, […], Lian X.

Link:
http://www.mdpi.com/2072-6643/10/2/185/htm

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A high dietary cholesterol intake is an intake of more than 200-300 mg cholesterol per day.

The result of a review article is only reliable when the result is also significant in cohort studies (thus not only significant in case-control studies).
 

Objectives:
Does the consumption of various types of tomato products reduce prostate cancer risk and is there a potential dose-response relationship?

Study design:
This review article included 30 studies, which summarized data from 24,222 cases (subjects with prostate cancer) among 260,461 participants.

Results and conclusions:
The investigators found that higher total tomato consumption was associated with a reduced risk of 19% for prostate cancer [RR = 0.81, 95% CI = 0.71 to 0.92, p = 0.001].

The investigators found in subgroup analysis that higher tomato foods consumption was associated with a reduced risk of 16% for prostate cancer [RR = 0.84, 95% CI = 0.72 to 0.98, p = 0.030].

The investigators found in subgroup analysis that higher cooked tomatoes and sauces consumption was associated with a reduced risk of 16% for prostate cancer [RR = 0.84, 95% CI = 0.73 to 0.98, p = 0.029]. 

The investigators found in subgroup analysis, however, no association between higher raw tomatoes consumption and prostate cancer risk [RR = 0.96, 95% CI = 0.84 to 1.09, p = 0.487].

The investigators found there was a significant dose-response association for total tomato consumption [p = 0.040], cooked tomatoes and sauces [p  0.001] and raw tomatoes [p = 0.037], but there was not a significant association with tomato foods [p-linear = 0.511, p-nonlinear = 0.289].

The investigators concluded that increased tomato consumption, particularly cooked tomatoes and sauces reduces prostate cancer risk. Furthermore, there are dose-response relationships for total tomato consumption and for cooked tomatoes and sauces. Further studies are required to determine the underlying mechanisms of these associations.

Original title:
Processed and raw tomato consumption and risk of prostate cancer: a systematic review and dose-response meta-analysis by Rowles JL, Ranard KM, […], Erdman JW Jr.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29317772

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