Nutrition and health

Objectives:
Epidemiologic studies focusing on the association between 1-carbon metabolism-related vitamins (ie, folate, vitamin B6, vitamin B2, vitamin B12) and breast cancer risk have reported inconsistent findings. Therefore, this review article (meta-analysis) has been conducted.

Does higher dietary intake of folate (folic acid), vitamin B2, B6 or B12 reduce breast cancer risk?

Study design:
This review article included 27 studies (case-control and cohort studies) with a total of 49,707 cases (persons with breast cancer) among 1,274,060 individuals.

Results and conclusions:
The investigators found for the highest folate dietary intake compared with the lowest, a significantly reduced risk of 7% [pooled relative risk = 0.93, 95% CI = 0.88 to 0.99, p = 0.018] for breast cancer.

The investigators found for the highest vitamin B6 dietary intake compared with the lowest, a significantly reduced risk of 6% [pooled relative risk = 0.94, 95% CI = 0.89 to 1.00, p = 0.037] for breast cancer.

The investigators found for the highest vitamin B2 dietary intake compared with the lowest, a significantly reduced risk of 10% [pooled relative risk = 0.90, 95% CI = 0.82 to 0.99, p = 0.026] for breast cancer.

The investigators found no significant association between vitamin B12 and breast cancer risk [RR = 0.99, 95% CI = 0.94 to 1.04, p = 0.604].

The investigators found folate and vitamin B6 dietary intake significantly decreased the risk of estrogen receptor-negative (ER-)/progesterone receptor-negative (PR-) breast cancer but not ER+/PR+ breast cancer.

The investigators found an increment of 100 μg/d folate dietary intake corresponded to a 7% [RR = 0.93, 95% CI = 0.89 to 0.98, p = 9.007] deceased risk of ER-/PR- breast cancer.

The investigators concluded both higher folate, vitamin B2 and B6 dietary intake decreases risk of breast cancer, especially ER-/PR- breast cancer.

Original title:
Association Between One-carbon Metabolism-related Vitamins and Risk of Breast Cancer: A Systematic Review and Meta-analysis of Prospective Studies by Zeng J, Gu Y, […], Chang H.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32241696

Additional information of El Mondo:
Find more information/studies on folate, vitamin B2 and B6 intake and breast cancer right here.

If breast cancer cells have estrogen receptors, the cancer is called ER-positive breast cancer. If breast cancer cells have progesterone receptors, the cancer is called PR-positive breast cancer. If the cells do not have either of these 2 receptors, the cancer is called ER/PR-negative.

Objectives:
Is there a causal relationship between daily egg consumption and positive effects on blood pressure?
 
Study design:
This review article included 15 RCTs with a total of 748 participants and mean age range from 23.3 to 67.1 years old.

All included studies used whole egg as an intervention which varied from one egg/day to three eggs/day and duration of supplementation ranged from 3 to 12 weeks.

No evidence of publication bias was seen in the meta-analyse (review article) of systolic blood pressure [Begg’s p = 0.235, Eggers’s p = 0.433] and diastolic blood pressure [Begg’s p = 0.254, Eggers’s p = 0.267].

No heterogeneity was found among included studies.

Results and conclusions:
The investigators found, overall, egg consumption had no significant effect on systolic blood pressure [WMD = 0.046 mmHg, 95% CI = - 0.792 to 0.884, p = 0.914, I2 = 0.0%, p = 0.453] and diastolic blood pressure [WMD = -0.603 mmHg, 95% CI = -1.521 to 0.315, p = 0.198, I2 = 38.1%, p = 0.067].
Subgroup analyses had no effect on pooled results.
Sensitivity analysis indicated that excluding each trial did not significantly change the overall observed effects of egg consumption.

The investigators found nonlinear dose-response meta-analysis did not reveal a significant effect of egg consumption [p-nonlinearity = 0.76] and study duration on diastolic blood pressure [p-nonlinearity = 0.63].

The investigators found subgroup analyses based on study design, sex, population health status, obesity and hypertension status, diet adherence, study duration and amount of egg consumption did not affect the overall effects of egg consumption on systolic blood pressure and diastolic blood pressure values.

The investigators concluded that 1-3 eggs/day during 3 to 12 weeks have no effect on blood pressure. However, high-quality RCTs with longer durations are needed to further confirm the effects of egg consumption on blood pressure.

Original title:
Effect of Egg Consumption on Blood Pressure: a Systematic Review and Meta-analysis of Randomized Clinical Trials by Kolahdouz-Mohammadi R, Malekahmadi M, […], Soltani S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7189334/

Additional information of El Mondo:
Find more information/studies on causal relationship/significantly, egg consumption and lowering of blood pressure right here.

Objectives:
Does Alzheimer disease increase risk of stroke?

Study design:
This review article included 8 studies, representing 121,719 individuals (Alzheimer disease = 73,044 and non-Alzheimer disease = 48,675).

Results and conclusions:
The investigators found patients with Alzheimer disease had a significantly increased risk of 42% [relative risk = 1.42, 95% CI = 1.23 to 1.64] for hemorrhagic stroke.

The investigators concluded Alzheimer disease increases risk of hemorrhagic stroke.

Original title:
Risk of hemorrhagic and ischemic stroke in patients with Alzheimer disease: A synthesis of the literature by Waziry R, Chibnik LB, […], Hofman A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31949087

Additional information of El Mondo:
Find more information/studies on Alzheimer disease right here.

Objectives:
The impact of light-intensity physical activity (LPA) in preventing cancer mortality has been questioned. Therefore, this review article has been conducted.

Does light-intensity physical activity reduce cancer mortality?

Study design:
This review article included 5 prospective cohort studies, in which the definition of light-intensity physical activity based on accelerometer readings was mainly set within 100 to 2,100 counts/min.

Results and conclusions:
The investigators found 30 min/day of light-intensity physical activity significantly reduced cancer mortality with 14% [summary HR = 0.86, 95% CI = 0.79 to 0.95, I2 1%] and the association between light-intensity physical activity and risk reduction in cancer mortality was linearly shaped [p nonlinearity = 0.72].

The investigators found light-intensity physical activity exhibited a comparable magnitude of risk reduction in cancer mortality of moderate-to-vigorous physical activity regardless of equal time-length [0.87 per 30 min/day vs. 0.94 per 30 min/day, p interaction = 0.46] or equal amount [0.74 vs. 0.94 per 150 metabolic equivalents-min/day, p interaction = 0.11].

The investigators found, furthermore, replacing sedentary time by light-intensity physical activity of 30 min/day significantly decreased the risk of cancer mortality by 9%.

The investigators concluded 30 min/day of light-intensity physical activity reduce cancer mortality.

Original title:
Objectively-Measured Light-Intensity Physical Activity and Risk of Cancer Mortality: A Meta-analysis of Prospective Cohort Studies by Qiu S, Cai X, […], Schumann U.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32303534

Additional information of El Mondo:
Find here more information/studies about sport nutrition and cancer.

Light intensity physical activity is an activity that is classified as 3 METS.

Objectives:
Is there a causal relationship between strawberry consumption and positive effects on cardiovascular risk factors?
 
Study design:
This review article included 11 RCTs (6 for blood pressure, 7 for lipid profile, 7 for fasting blood glucose and 6 for C-reactive protein).

There was little evidence of heterogeneity in the analysis and no evidence of publication bias.

Results and conclusions:
The investigators found overall, strawberry consumption significantly reduced C-reactive protein (CRP) levels by 0.63 mg/L [95% CI = -1.04 to -0.22] but did not affect blood pressure, lipid profile or fasting blood glucose in the main analyses.

The investigators found stratified by baseline endpoint levels, that strawberry consumption significantly reduced total cholesterol levels among people with baseline levels >5 mmol/L [-0.52 mmol/L, 95% CI = -088 to -0.15] and reduced LDL-cholesterol levels among people with baseline levels >3 mmol/L [-0.31 mmol/L, 95% CI = -0.60 to -0.02].

The investigators concluded strawberry consumption reduces C-reactive protein (CRP) levels and improves total cholesterol and LDL-cholesterol (bad cholesterol) in individuals with high baseline levels (level at the beginning of the study).

Original title:
Effects of strawberry intervention on cardiovascular risk factors: a meta-analysis of randomized controlled trials by Gao Q, Qin LQ, […], Dong JY.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32238201

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Find more information/studies on fruit consumption and lowering of cholesterol levels right here.

Objectives:
Does fish consumption decrease risk of cardiovascular disease, depression, mortality and cancer?
 
Study design:
This review article included a total of 34 meta-analyses of prospective observational studies, reporting summary relative risks (SRR) for 40 different outcomes obtained from 298 primary prospective cohort studies.

The summary relative risk (SRR) for each meta-analysis was recalculated by using a random-effects model.

Results and conclusions:
The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 8% lower risk of all-cause mortality [SRR = 0.92, 95% CI = 0.87 to 0.97].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 25% lower risk of cardiovascular mortality [SRR = 0.75, 95% CI = 0.65 to 0.87].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 12% lower risk of coronary heart disease [SRR = 0.88, 95% CI = 0.79 to 0.99].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 25% lower risk of myocardial infarction [SRR = 0.75, 95% CI = 0.65 to 0.93].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 14% lower risk of stroke [SRR = 0.86, 95% CI = 0.75 to 0.99].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 20% lower risk of heart failure [SRR = 0.80, 95% CI = 0.67 to 0.95].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 12% lower risk of depression [SRR = 0.88, 95% CI = 0.79 to 0.98].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 35% lower risk of liver cancer [SRR = 0.65, 95% CI = 0.48 to 0.87].

The investigators concluded evidence of moderate quality shows that 100-g/d fish consumption is associated with a lower risk of cardiovascular disease, depression, mortality and liver cancer and therefore, can be considered as a healthy animal-based dietary source of protein. Further research is needed for outcomes for which the quality of the evidence was rated low and very low, considering types of fish consumed, different methods of cooking fish and all potential confounding variables.

Original title:
Fish Consumption and the Risk of Chronic Disease: An Umbrella Review of Meta-Analyses of Prospective Cohort Studies by Jayedi A and Shab-Bidar S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32207773

Additional information of El Mondo:
Find more information/studies on fish consumption, cancer and cardiovascular disease right here.

Objectives:
Do fermented dairy foods and probiotics supplementation improve risk factors (such as metabolic syndrome, type 2 diabetes, cholesterol) of cardiovascular diseases?

Study design:
This review article included 20 prospective cohort studies and 52 RCTs.

Results and conclusions:
The investigators found in prospective cohort studies, that fermented milk was associated with a 4% reduction in risk of stroke, ischemic heart disease and cardiovascular mortality [RR = 0.96, 95% CI = 0.94 to 0.98].

The investigators found in prospective cohort studies, that yogurt intake was associated with a risk reduction of 27% [RR = 0.73, 95% CI = 0.70 to 0.76] for type 2 diabetes.

The investigators found in prospective cohort studies, that yogurt intake was associated with a risk reduction of 20% [RR = 0.80, 95% CI = 0.74 to 0.87] for metabolic syndrome development.

The investigators found in RCTs, that probiotic supplementation added into dairy matrices produced a greater reduction in lipid biomarkers than when added into capsules/powder in hypercholesterolemic subjects.

The investigators found in RCTs, that probiotic supplementation by capsules/powder produced a greater reduction in type 2 diabetes biomarkers than when added into dairy matrices in diabetic subjects.

The investigators found in RCTs, that probiotic supplementation by both treatments (dairy matrix and capsules/powder) resulted in a significant reduction in anthropometric parameters in obese subjects.

The investigators concluded fermented milk consumption is associated with reduced cardiovascular risk, while yogurt intake is associated with a reduced risk of type 2 diabetes and metabolic syndrome development in the general population. Furthermore, probiotic supplementation added into dairy matrices is beneficial for lowering lipid concentrations and reduce anthropometric parameters. Additionally, probiotic capsule/powder supplementation contributes to type 2 diabetes management and reduces anthropometric parameters. However, these results should be interpreted with caution due to the heterogeneity of the studies and the different probiotic strains used in the studies.

Original title:
Fermented Dairy Products, Probiotic Supplementation, and Cardiometabolic Diseases: A Systematic Review and Meta-analysis by Companys J, Pla-Pagà L, […], Valls RM.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32277831

Additional information of El Mondo:
Find more information/studies on probiotic, diabetes, overweight and cardiovascular disease right here.

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:
Does tea consumption decrease risk of cardiovascular disease and all-cause mortality among adults?
 
Study design:
This review article included 39 prospective cohort studies.

Strength of evidence was rated as low and moderate (depending on study population age group) for cardiovascular disease-specific mortality outcome and was rated as low for cardiovascular disease events, stroke and all-cause mortality outcomes.

Results and conclusions:
The investigators found linear meta-regression showed that each cup (236.6 mL) increase in daily tea consumption (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) was associated with an average 4% lower risk of cardiovascular disease mortality, a 2% lower risk of cardiovascular disease events, a 4% lower risk of stroke and a 1.5% lower risk of all-cause mortality.

The investigators found subgroup meta-analysis showed that each cup (236.6 mL) increase in daily tea consumption (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) was associated with a 11% [pooled adjusted RR = 0.89, 95% CI = 0.83 to 0.96, p = 0.001, I2 = 72.4%, n = 4] lower risk of cardiovascular disease mortality in elderly individuals.

The investigators found subgroup meta-analysis showed that each cup (236.6 mL) increase in daily tea consumption (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) was associated with a 8% [pooled adjusted RR = 0.92, 95% CI = 0.90 to 0.94, p 0.0001, I2 = 0.3%, n = 3] lower risk of all-cause mortality in elderly individuals.

The investigators found, generally, studies with higher risk of bias appeared to show larger magnitudes of associations than studies with lower risk of bias.

The investigators concluded that daily a cup (236.6 mL) of tea (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) is associated with a lower risk of cardiovascular disease and all-cause mortality among elderly individuals.

Original title:
Dose-Response Relation between Tea Consumption and Risk of Cardiovascular Disease and All-Cause Mortality: A Systematic Review and Meta-Analysis of Population-Based Studies by Chung M, Zhao N, […], Wallace TC.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32073596

Additional information of El Mondo:
Find more information/studies on tea consumption and cardiovascular disease 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/

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

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/

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

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

Objectives:
Does flaxseed supplementation decrease plasma lipoprotein(a) levels?

Study design:
This review article included 7 RCTs with 629 individuals.

Results and conclusions:
The investigators found flaxseed supplementation significantly reduced plasma lipoprotein(a) levels [MD = -2.06 mg/dL, 95% CI = -3.846 to -0.274, p = 0.024, I2 = 0%, p = 0.986].

The investigators found subgroup analysis also revealed that longer duration only showed significant lowering effect of flaxseed supplementation on plasma lipoprotein(a) levels.

The investigators concluded that long duration of flaxseed supplementation decreases plasma lipoprotein(a) levels. However, future well-designed and long-term clinical trials are required to confirm these results.

Original title:
Impact of flaxseed supplementation on plasma lipoprotein(a) concentrations: A systematic review and meta-analysis of randomized controlled trials by Hadi A, Askarpour M, […], Ghavami A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32073724

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Find here more information/studies about flaxseed and heart disease.

Lipoprotein(a) is a risk factor for atherosclerosis and related diseases, such as coronary heart disease and stroke.

 

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

Additional information of El Mondo:
Find more information/studies on calcium, vitamin C, D, E, breast cancer and colorectal cancer right here.

Objectives:
Vitamin C as a supplement to treat hypertension has been proposed. However, it remains controversial whether vitamin C can improve blood pressure in patients with primary hypertension. Therefore, this review article has been conducted.

Do vitamin C supplements reduce blood pressure in patients with primary hypertension?

Study design:
This review article included 8 RCTs involving 614 participants.
There was no publication bias.

Results and conclusions:
The investigators found vitamin C supplements significantly reduced systolic blood pressure in patients with essential hypertension [WMD  = -4.09, 95% CI = -5.56 to -2.62, p 0 .001, I2  =  35%, p = 0.15].

The investigators found vitamin C supplements significantly reduced diastolic blood pressure in patients with essential hypertension [WMD  = -2.30, 95% CI = -4.27 to -0.331, p  = 0 .02, I2 = 75%, p = 0 .0002].

The investigators found vitamin C supplements significantly reduced systolic blood pressure for the subgroup with an age ≥60 years and that with ≥35 participants [WMD = -3.75, 95% CI = -6.24 to -1.26, p  = 0 .003].

The investigators found vitamin C supplements significantly reduced diastolic blood pressure for the subgroup with an age ≥60 years and that with ≥35 participants [WMD = -3.29, 95% CI = -5.98 to -0.60, p  = 0 .02].

The investigators found in the subgroup analysis that vitamin C supplements during ≥6 weeks significantly reduced systolic blood pressure in patients with essential hypertension [WMD = -4.77, 95% CI = -6.46 to -3.08, p   0 .001].

The investigators found in the subgroup analysis that ≥500 mg/d vitamin C supplements significantly reduced systolic blood pressure in patients with essential hypertension [WMD  =  -5.01, 95% CI = -8.55 to -1.48, p  = 0.005, I2  =  44%, p =  0.13].

The investigators concluded ≥500 mg/d vitamin C supplements during ≥6 weeks reduce blood pressure in patients with primary hypertension. However, in view of the current level of evidence, large-scale trials should be conducted and attention should be paid to the evaluation of blood pressure variability.

Original title:
Effects of vitamin C supplementation on essential hypertension: A systematic review and meta-analysis by Guan Y, Dai P and Wang H.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7034722/

Additional information of El Mondo:
Find more information/studies on lowering of blood pressure, vitamin C and cardiovascular disease right here.

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:
Clinical trials examining the cardiovascular protective effects of quercetin in humans have reported conflicting results. Therefore, this review article has been conducted.

Do quercetin supplements reduce plasma lipid levels and blood pressure?

Study design:
This review article included 17 RCTs with a total of 896 participants.

Results and conclusions:
The investigators found pooled results showed that quercetin supplements significantly lowered both systolic blood pressure [WMD = -3.09 mmHg, 95% CI = -4.59 to -1.59, p = 0.0001] and diastolic blood pressure [WMD = -2.86 mmHg, 95% CI = -5.09 to -0.63, p = 0.01].
Neither lipid profiles nor glucose concentrations changed significantly.

The investigators found in subgroup analyses, significant changes in high-density lipoprotein (HDL or good) cholesterol and triglycerides were observed in trials with a parallel design and in which participants consumed quercetin for 8 weeks or more.

The investigators concluded quercetin supplements decrease blood pressure in humans. Moreover, participants who consume quercetin for 8 weeks or more show significantly changed levels of high-density lipoprotein cholesterol (good cholesterol) and triglycerides in trials with a parallel design.  

Original title:
Effect of quercetin supplementation on plasma lipid profiles, blood pressure, and glucose levels: a systematic review and meta-analysis by Huang H, Liao D, [...], Pu R.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31940027

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

Objectives:
Data from in vitro and animal studies support the preventive effect of tea (Camellia sinensis) against colorectal cancer. Further, many epidemiologic studies evaluated the association between tea consumption and colorectal cancer risk, but the results were inconsistent. Therefore, this review article has been conducted.

Does tea consumption reduce colorectal cancer risk?

Study design:
This review article included 20 cohort studies with 2,068,137 participants and 21,437 colorectal cancer cases.

Results and conclusions:
The investigators found that tea consumption had no significant association with colorectal cancer risk for the highest vs. lowest categories [combined RR = 0.97, 95% CI = 0.94-1.01, I2 = 24.0%, p = 0.093] among all studies.

The investigators found stratified analysis showed no significant differences in all subgroups.

The investigators found no significant association between tea consumption and colorectal cancer risk in male [combined RR = 0.97, 95% CI = 0.90-1.04].

The investigators found, however, tea consumption had a marginal significant inverse impact on colorectal cancer risk in female [combined RR = 0.93, 95% CI = 0.86-1.00].

The investigators found a significantly reduced risk of 10% for colorectal cancer for tea consumption among the female studies with no adjustment of coffee intake [RR = 0.90, 95% CI = 0.82-1.00, p  0.05].
However, this reduced risk was not significant among the female studies that adjusted for coffee intake [RR = 0.97, 95% CI = 0.87-1.09, p > 0.05].

The investigators concluded that tea consumption may reduce colorectal cancer risk in female. May reduced because this reduced risk was not significant among the female studies that adjusted for coffee intake.

Original title:
Tea consumption and colorectal cancer risk: a meta-analysis of prospective cohort studies by Zhu MZ, Lu DM, […], Liu ZH.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32078065

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

Objectives:
There are differences among the outcomes regarding cognitive impairment in heart failure (HF) because the evidence is fragmented and sample size is small. Therefore, this review article has been conducted.

Does heart failure increase risk of dementia?

Study design:
This review article included 12 studies with 2,406,680 heart failure patients.

Begg test, Egger tests and funnel plots showed no significant risks of publication bias.

Results and conclusions:
The investigators found heart failure significantly increased risk of all-cause dementia with 28% [OR/RR  =  1.28, 95% CI = 1.15 to 1.43, I2 = 70.0%, p    0.001].
Sensitivity analysis showed no changes in the direction of effect when any one study was excluded for the studies on associations between heart failure and all-cause dementia.

The investigators found no significant association between heart failure and risk of Alzheimer's disease [OR/RR  =  1.38, 95% CI = 0.90 to 2.13, I 2 =  74.8%, p =  0.008].
Sensitivity analysis showed no changes in the direction of effect when any one study was excluded for the studies on associations between heart failure and Alzheimer's disease.

The investigators concluded heart failure increases risk of all-cause dementia. In addition, large scale prospective studies are essential to explore the associations between heart failure and risk of Alzheimer's disease.

Original title:
Associations between heart failure and risk of dementia: A PRISMA-compliant meta-analysis by Li J, Wu Y, [...], Nie J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7004760/

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

Objectives:
The benefits of LDL cholesterol-lowering treatment for the prevention of atherosclerotic cardiovascular disease are well established. However, the extent to which these effects differ by baseline LDL cholesterol, atherosclerotic cardiovascular disease risk and the presence of comorbidities remains uncertain. Therefore, this review article has been conducted.

Does LDL cholesterol-lowering treatment reduce risk of major vascular events (a composite of cardiovascular mortality, non-fatal myocardial infarction, non-fatal ischaemic stroke or coronary revascularisation)?

Study design:
This review article included 52 RCTs with a total of 327,037 patients.

Results and conclusions:
The investigators found each 1 mmol/L reduction in LDL cholesterol (bad cholesterol) was associated with a 19% relative risk (RR) reduction for major vascular events [RR = 0.81, 95% CI = 0.78 to 0.84,  p 0.0001].

The investigators found similar reductions (per 1 mmol/L reduction in LDL cholesterol) in trials with participants with LDL cholesterol level of 2.60 mmol/L or lower, 2.61-3.40 mmol/L, 3.41-4.10 mmol/L and more than 4.1 mmol/L [p = 0.232 for interaction] and in a subgroup of patients who all had a baseline LDL cholesterol level less than 2.07 mmol/L [80 mg/dL: RR = 0.83, 95% CI = 0.75-0.92, p = 0.001].

The investigators found greater RR reductions in patients at lower 10-year atherosclerotic cardiovascular disease risk [change in RR per 10% lower 10-year atherosclerotic cardiovascular disease = 0.97, 95% CI = 0.95 to 0.98, p 0.0001] and in patients at younger age across a mean age of 50-75 years [change in RR per 10 years younger age = 0.92, 95% CI = 0.83 to 0.97, p = 0.015].

The investigators found no difference in RR reduction for participants with or without diabetes [p = 0.878 for interaction] and chronic kidney disease [p = 0.934 for interaction].

The investigators concluded for each 1 mmol/L LDL cholesterol lowering, the risk reduction of major vascular events is independent of the starting LDL cholesterol or the presence of diabetes or chronic kidney disease. Patients at lower cardiovascular risk and younger age might have a similar relative reduction in risk with LDL-cholesterol lowering therapies and future studies should investigate the potential benefits of earlier intervention.

Original title:
Intensive LDL cholesterol-lowering treatment beyond current recommendations for the prevention of major vascular events: a systematic review and meta-analysis of randomised trials including 327 037 participants by Wang N, Fulcher J, […], Lal S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31862150

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

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

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

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

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

Objectives:
Evidence has shown that essential nutrients are highly correlated with the occurrence of esophageal cancer (EC). However, findings from observational studies on the associations between dietary carbohydrate, salt consumption and the risk of esophageal cancer remain controversial. Therefore, this review article has been conducted.

Does carbohydrate or salt consumption (dietary salt intake) increase risk of esophageal cancer?

Study design:
This review article included 11 case-control studies and 1 cohort study, examined carbohydrates consumption and 16 case-control studies and 2 cohort studies, examined salt consumption.

Results and conclusions:
The investigators found dietary carbohydrate intake significantly reduced risk of esophageal cancer with 38% [pooled OR = 0.62, 95% CI = 0.50-0.77].

The investigators found dietary salt intake significantly increased risk of esophageal cancer with 97% [OR = 1.97, 95% CI = 1.50-2.61] in case-control studies.

The investigators found dietary salt intake significantly increased risk of esophageal cancer with 4% [RR = 1.04, 95% CI = 1.00-1.08] in cohort studies.

The investigators concluded dietary salt intake increases risk of esophageal cancer.

Original title:
Associations of dietary carbohydrate and salt consumption with esophageal cancer risk: a systematic review and meta-analysis of observational studies by Banda KJ, Chiu HY, [...], Huang HC.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31995192

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

According to WHO, a high salt intake is a salt intake of more than 5 grams salt per day.

A diet with more than 5 grams salt per day is a diet with mainly products/meals with more than 0.25 grams salt per 100 kcal. Check here which products contain maximum 5 grams salt per 100 kcal.
Use the 7-points nutritional profile app to see whether your daily diet contains maximum 5 grams salt per 100 kcal.

 

Objectives:
Low-carbohydrate diets are associated with cardiovascular risk factors; however, the results of different studies are inconsistent. Therefore, this review article has been conducted.

Do low-carbohydrate diets (diets with less than 40 En% carbohydrates) reduce cardiovascular risk factors?

Study design:
This review article included 12 RCTs with a total of 820 in the observation group (intervention group or low carbohydrate group) and 820 in the control group. The largest sample size was 403 cases and the smallest was 42 cases. The patients’ ages ranged from 31 to 65 years old.
The intervention was a diet with less than 40 En% carbohydrates in the observation group and a diet with 45 En% to 55 En% carbohydrates in the control group.

Results and conclusions:
The investigators found compared with the control group, the triglyceride levels of the low-carbohydrate group (less than 40 En% carbohydrates) significantly decreased by 0.15 mmol/L [95% CI = -0.23 to -0.07, I2 = 75%, p = 0.001].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The results of the publication bias analysis showed that the funnel plot was not symmetric. The asymmetry of the funnel plot may have been caused by publication bias and other issues.

The investigators found in subgroup analyses, low-carbohydrate diet interventions lasting less than 6 months significantly decreased the triglyceride levels by 0.23 mmol/L [95% CI = -0.32 to -0.15] and those of 12-23 months decreased the levels by 0.17 mmol/L [95% CI = -0.32 to -0.01].

The investigators found compared with the control group, the plasma HDL-cholesterol level (good cholesterol) of the low-carbohydrate group significantly increased by 0.1 mmol/L [95% CI = 0.08 to 0.12, I2 = 41%, p = 0.02].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found in subgroup analyses, the increase in plasma HDL-cholesterol levels was 0.08 mmol/L [95% CI = 0.27 to 0.57] for interventions lasting less than 6 months, 0.12 mmol/L [95% CI = 0.09 to 0.15] for those lasting 6-11 months, 0.12 mmol/L [95% CI = 0.08 to 0.15] for those lasting 12-23 months and 0.08 mmol/L [95% CI = 0.04 to 0.12] for those lasting 24 months. 

The investigators found compared with the control group, the serum total cholesterol level of the low-carbohydrate group significantly increased by 0.13 mmol/L [95% CI = 0.08 to 0.19].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found compared with the control group, the plasma LDL-cholesterol level (bad cholesterol) of the low-carbohydrate group significantly increased by 0.11 mmol/L [95% CI = 0.02 to 0.19, I2 = 71%, p = 0.0001].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found compared with the control group, the body weight of the low-carbohydrate group significantly decreased by 1.58 kg [95% CI = -1.58 to -0.75, I2 = 49%, p = 0.01].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found in subgroup analyses, the decrease in body weight was 1.14 kg [95% CI = -1.65 to -0.63] for interventions lasting less than 6 months and 1.73 kg [95% CI = -2.7 to -0.76] for those lasting 6-11 months.

The investigators found compared with the control group, the overall systolic blood pressure of the low-carbohydrate group significantly decreased by 1.41 mmHg [95% CI = -2.26 to -0.56, I2 = 0%, p = 0.84].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found in subgroup analyses, the overall systolic blood pressure significantly decreased by 2.97 mmHg [95% CI = -4.62 to -1.31] in the group that received interventions lasting less than 6 months.

The investigators found compared with the control group, the diastolic blood pressure of the low-carbohydrate group significantly decreased by 1.71 mmHg [95% CI = -2.36 to -1.06, I2 = 14%, p = 0.29].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found in subgroup analyses, the diastolic blood pressure significantly decreased by 2.76 mmHg [95% CI = -4.07 to -1.46] in the group that received interventions lasting less than 6 months and 2.11 mmHg [95% CI = -3.28 to -0.93] for those lasting 6-11 months.

The investigators concluded low-carbohydrate diets (diets less than 40 En% carbohydrates) have beneficial effects on cardiovascular risk factors at less than 6 months and 6-11 months, but after 2 years of a low-carbohydrate diet, there is no significant effect on cardiovascular risk factors.

Original title:
The effects of low-carbohydrate diets on cardiovascular risk factors: A meta-analysis by Dong T, Guo M, [...], Chen B.

Link:
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0225348

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

40 En% carbohydrates means that the total amounts of carbohydrate make up for a 40% of the total kcal of the diet. The easiest way to follow this diet is to choose only meals/products that also contain 40 En% carbohydrates. These products in the supermarket contain 40 En% carbohydrates.

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

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

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

Additional information of El Mondo:
Find more information/studies on significantly/cohort studies, garlic consumption and colorectal cancer right here.