Nutrition and health

Objectives:
Many studies suggest that high-fat diets are linked to the etiology of non-Hodgkin's lymphoma (NHL). However, the findings are inconsistent and therefore the association between fat and non-Hodgkin's lymphoma remains unclear. Therefore, this review article (meta-analysis) has been conducted.

Does a high fat dietary intake increase non-Hodgkin's lymphoma risk?

Study design:
This review article included two cohort studies and eight case-control studies.

The funnel plot revealed no evidence for publication bias.

Results and conclusions:
The investigators found a significant higher risk of 26% for non-Hodgkin's lymphoma for total fat consumption [RR = 1.26, 95% CI = 1.12-1.42]. Significant because RR of 1 was not found in the 95% CI of 1.12 to 1.42. RR of 1 means no risk/association.

The investigators found subgroup analysis showed a significant higher risk of 41% for diffuse large B-cell lymphoma for total fat consumption [RR = 1.41, 95% CI = 1.08-1.84]. However, there was no significant association between total fat consumption and increase risk of follicular lymphoma [RR = 1.21, 95% CI = 0.97-1.52], small lymphocytic lymphoma/chronic lymphocytic leukemia [RR = 0.91, 95% CI = 0.68-1.23] nor with T cell lymphoma [RR = 1.12, 95% CI = 0.60-2.09].
No significant because RR of 1 was found in the 95% CI of 0.60 to 2.09. RR of 1 means no risk/association.

The investigators concluded that total fat consumption increases non-Hodgkin's lymphoma; especially diffuse large B-cell lymphoma.

Original title:
Dietary Fat Consumption and Non-Hodgkin's Lymphoma Risk: A Meta-analysis by Han TJ, Li JS, [...], Xu HZ.

Link:

https://www.ncbi.nlm.nih.gov/pubmed/28094569

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

Lymphoma is the most common blood cancer. The two main forms of lymphoma are Hodgkin lymphoma and non-Hodgkin lymphoma (NHL). The human body has two main types of lymphocytes that can develop into lymphomas:

1. B lymphocytes (B cells) and;
2. T lymphocytes (T cells).

B-cell lymphomas are much more common than T-cell lymphomas and account for approximately 85 percent of all non-Hodgkin lymphomas. Diffuse large B cell lymphomas (DLBCLs) are the commonest subtype of non-Hodgkin's lymphoma. They constitute about 30 to 40% of adult non-Hodgkin's lymphoma.

A high total fat consumption corresponds to a diet with >35 En% fat and/or >10 En% saturated fat. A diet with >35 En% fat is a diet with a lot of products/meals providing >35 En% fat.
 

Objectives:
Several epidemiological studies investigating the association between dietary vitamin E intake and the risk of lung cancer have demonstrated inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Does dietary vitamin E intake reduce lung cancer risk?

Study design:
This review article included 9 cohort studies with 4,164 lung cancer cases among 435,532 participants.

The Egger’s test showed no evidence of publication bias [t = 1.24, p = 0.246].

Results and conclusions:
The investigators found for the highest versus lowest categories of dietary vitamin E intake a reduced risk of 16% for lung cancer [pooled RR = 0.84, 95% CI = 0.76-0.93, I2 = 41.1%].

The investigators found in subgroup analysis by geographic location a significant inverse association of dietary vitamin E intake with lung cancer for the European and American populations [pooled RR = 0.85, 95% CI = 0.75-0.95), but not for the Asian population. Significant means that there is an association with a 95% confidence.

The investigators found every 2 mg/d increase in dietary vitamin E intake statistically decreased the risk of lung cancer by 5% [RR = 0.95, 95% CI = 0.91-0.99, p linearity = 0.0237].

The investigators concluded that higher dietary vitamin E intake; at least 2 mg per day exerts a protective effect against lung cancer.

Original title:
Association of dietary vitamin E intake with risk of lung cancer: a dose-response meta-analysis by Zhu YJ, Bo YC, [...], Qiu CG.

Link:
http://apjcn.nhri.org.tw/server/APJCN/26/2/271.pdf

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

Objectives:
Epidemiological studies suggest that soya consumption as a source of phyto-oestrogens and isoflavones may be associated with a reduced risk of colorectal cancer. However, findings have not yet been synthesised for all groups of phyto-oestrogens. Therefore, this review article (meta-analysis) has been conducted.

Does soya consumption reduce colorectal cancer risk?

Study design:
This review article included 16 studies (case-control studies and cohort studies).

Results and conclusions:
The investigators found in case-controle studies a significant reduced risk of 24% [pooled RR = 0.76, 95% CI = 0.69-0. 84] for colorectal cancer when comparing the highest phyto-oestrogens with the lowest intake category. However, the reduced risk for colorectal cancer was not significant in cohort studies [pooled RR = 0.95, 95% CI = 0.85-1.06].

The investigators found in case-controle studies a significant reduced risk of 23% [pooled RR = 0.77, 95% CI = 0.69-0. 85] for colorectal cancer when comparing the highest isoflavones with the lowest intake category. However, the reduced risk for colorectal cancer was not significant in cohort studies [pooled RR = 0.94, 95% CI = 0.84-1.05].

The investigators found in case-controle studies a significant reduced risk of 30% [pooled RR = 0.70, 95% CI = 0.56-0. 89] for colorectal cancer when comparing the highest lignans with the lowest intake category. However, the reduced risk for colorectal cancer was not significant in cohort studies [pooled RR = 1.00, 95% CI = 0.64-1.57].

The investigators found dose-response analysis yielded an 8% reduced risk of colorectal neoplasms for every 20 mg/d increase in isoflavones intake in Asians [pooled RR = 0.92, 95% CI = 0.86-0.97].

The investigators found dose-response analysis showed a non-linear inverse association with colorectal cancer risk for lignans intake, but no association for circulating enterolactone concentrations was observed.

The investigators concluded every 20 mg/d increase in isoflavones dietary intake reduces risk of colorectal neoplasms with 8% in Asians.

Original title:
Phyto-oestrogens and colorectal cancer risk: a systematic review and dose-response meta-analysis of observational studies by Jiang R, Botma A, […], Chang-Claude J.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28091359

Additional information of El Mondo:
Find more information/studies on isoflavones, colorectal cancer and cohort study/review article right here.

Objectives:
Some observational studies have shown that elevated serum selenium levels are associated with reduced prostate cancer risk. However, not all published studies support these results. Therefore, this review article (meta-analysis) has been conducted.

Does an elevated serum selenium level reduce prostate cancer risk?

Study design:
This review article included 12 case-control studies, 4 cohort studies and 1 RCT with 6,136 prostate cancer cases among 34,901 participants.

Results and conclusions:
The investigators found elevated serum selenium levels significantly decreased prostate cancer risk with 24% [pooled OR = 0.76, 95% CI = 0.64 to 0.91, I2  =  60.8%, p  =  0.001].  Significant means that there is an association with a 95% confidence.

The investigators found in subgroup analysis, an inverse association between elevated serum selenium levels and prostate cancer risk in case-control studies, current and former smokers, high-grade cancer cases, advanced cancer cases and different populations. However, such correlations were not found among cohort studies, nonsmokers, low-grade cancer cases and early stage cancer cases.

The investigators concluded that elevated serum selenium levels may decrease high-grade prostate cancer among current and former smokers. May decrease because the inverse relationship between elevated serum selenium levels and prostate cancer risk was not significant among cohort studies. Therefore, further cohort studies and randomized control trials based on non-Western populations are required.

Original title:
Serum selenium levels and prostate cancer risk: A MOOSE-compliant meta-analysis by Cui Z, Liu D, […], Liu G.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5293444/

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