Are vitamins relevant to cancer risks? A Mendelian randomization investigation

Cheng, Wenwen; Wang, Ze-Kun; Shangguan, Huang-Fang; Zhu, Qiang; Zhang, Hongyu

doi:10.1016/j.nut.2020.110870

Cited by 14 publications

(9 citation statements)

References 31 publications

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“…In another meta-analysis study examining methylenetetrahydrofolate reductase polymorphisms (MTHFR C677T) and B9 and B12 intake concluded that low intake of folate was associated with increased risk of breast cancer, whereas no association were found for B12 [132]. A study seeking to find genetic associations between vitamins and five cancers also concluded that B12 was not relevant to colorectal, breast, prostate, malignant melanoma or squamous cell carcinoma [133]. A study of B vitamins involved in one-carbon metabolism in the setting of esophageal cancer found that vitamin B2 and B12 were positively correlated with cancer risk, whereas vitamin B6 and B9 were inversely correlated [94].…”

Section: One-carbon Metabolismmentioning

confidence: 99%

B Vitamins and Their Role in Immune Regulation and Cancer

et al. 2020

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B group vitamins represent essential micronutrients for myriad metabolic and regulatory processes required for human health, serving as cofactors used by hundreds of enzymes that carry out essential functions such as energy metabolism, DNA and protein synthesis and other critical functions. B vitamins and their corresponding vitamers are universally essential for all cellular life forms, from bacteria to humans. Humans are unable to synthesize most B vitamins and are therefore dependent on their diet for these essential micronutrients. More recently, another source of B vitamins has been identified which is derived from portions of the 1013 bacterial cells inhabiting the gastrointestinal tract. Here we review the expanding literature examining the relationship between B vitamins and the immune system and diverse cancers. Evidence of B vitamin’s role in immune cell regulation has accumulated in recent years and may help to clarify the disparate findings of numerous studies attempting to link B vitamins to cancer development. Much work remains to be carried out to fully clarify these relationships as the complexity of B vitamins’ essential functions complicates an unequivocal assessment of their beneficial or detrimental effects in inflammation and cancers.

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Section: One-carbon Metabolismmentioning

confidence: 99%

B Vitamins and Their Role in Immune Regulation and Cancer

et al. 2020

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“…All three studies 10,29,30 reported a positive association between vitamin B 12 and CRC, and the OR (95% CI) was 1.16 (1.08–1.25) in the largest one, 30 whereas no associations were found for vitamin D/25‐hydroxyvitamin D (25(OH)D), 10,22–28 β‐carotene, 29 retinol, 10 carotenoids, 10 vitamin E, 10,22 folate, 29,30 vitamin B 6 , 10,29,30 methionine, 10 zinc, 10,29 calcium, 10,29 selenium, 10,29 iron, 10,29 copper, 29 magnesium, 29 phosphorus, 29 and 24‐h urinary sodium 31 (Table 1, Figures 2 and 3, Figure S3).…”

Section: Resultsmentioning

confidence: 99%

“…The sample size of exposure and outcome ranged between 1475 and 898 130 and between 1475 and 706 031, respectively (Table S3). The causal factors can be classified into eight categories: anthropometric characteristics and obesity‐related biomarkers ( n = 31), 7–16 lifestyle habits ( n = 15), 9,10,17–21 blood micronutrients ( n = 36), 10,22–31 blood fatty acids (FAs) and lipids ( n = 43), 10,24,32–37 inflammatory biomarkers ( n = 14), 10,38–42 pathological conditions and related biomarkers ( n = 30), 10,43–50 reproductive factors ( n = 12), 10,51,52 and other biomarkers ( n = 9) 10,53–57 (Table 1, Figure 2).…”

Section: Resultsmentioning

confidence: 99%

Associations between potential causal factors and colorectal cancer risk: A systematic review and meta‐analysis of Mendelian randomization studies

Deng

Wang

Huang

et al. 2022

J of Digest Diseases

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To summarize the associations between potential causal factors and colorectal cancer (CRC) risk based on existing Mendelian randomization studies.Methods: This systematic review and meta-analysis involved a literature search in Embase and Medline. All published articles using Mendelian randomization to explore potential causal factors of CRC were included. Studies that reported Mendelian randomization estimates of standard deviation changes in exposures were included in the meta-analysis. Subgroup analyses based on sex and anatomical sites were performed.Results: One hundred and ninety studies presented in 51 articles were included in systematic review, and 114 studies conducted in 32 articles were included in the meta-analysis. Adult body mass index, waist circumference, waist hip ratio, body height, body fat percentage, arm fat ratio, childhood obesity, lifetime cigarette consumption, short sleep, coffee consumption, and blood levels of vitamin B 12 , arachidonic acid, stearic acid, and insulin-like growth factor binding protein 3 were positively associated with CRC risk. Conversely, acceleration-vector-magnitude physical activity, milk consumption, and blood levels of adiponectin, linoleic acid, α-linolenic acid, oleic acid, palmitoleic acid, interleukin-6 receptor subunit-α, and tumor necrosis factor were inversely associated with CRC risk.Conclusions: Most obesity-related anthropometric characteristics, several unhealthy lifestyles, and blood levels of some micronutrients, fatty acids, and diabetes-related biomarkers were positively associated with CRC risk. In contrast, some lifestyles and blood levels of some fatty acids and inflammatory biomarkers were inversely associated with CRC risk. Future studies with more valid genetic variants are needed for factors with discrepancies between Mendelian randomization and epidemiological studies.

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“…In these cases, having a wide array of MR and RCT studies (ideally meta-analysed) can be helpful in establishing the likely true causal direction of effect. For instance, 2 MR studies 109,110 , a meta-analysis of 5 RCT studies 111 and two RCTs 112,113 indicate no effect of vitamin E on prostate cancer incidence with one outlier RCT 114 showing benefit of vitamin E supplementation in older smokers. Similar contrary findings were found for 1 RCT 115 showing beneficial effect of vitamin D on preventing depressive symptoms, as opposed to null effect in 4 MR studies [116][117][118][119] and 2 RCTs 120,121 .…”

Section: Combining Rct and Mr Results Can Offer Complimentary Evidenc...mentioning

confidence: 99%

Systematic comparison of Mendelian randomization studies and randomized controlled trials using electronic databases

Sobczyk

Smith

Gaunt

2022

Preprint

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Mendelian Randomization (MR) uses genetic instrumental variables to make causal inferences. Whilst sometimes referred to as "nature's randomized trial", it has distinct assumptions that make comparisons between the results of MR studies with those of actual randomized controlled trials (RCTs) invaluable. To scope the potential for (semi-)-automated triangulation of MR and RCT evidence, we mined ClinicalTrials.Gov, PubMed and EpigraphDB databases and carried out a series of 26 manual literature comparisons among 54 MR and 77 RCT publications. We found that only 11% of completed RCTs identified in ClinicalTrials.Gov submitted their results to the database. Similarly low coverage was revealed for Semantic Medline (SemMedDB) semantic triples derived from MR and RCT publications - 25% and 12%, respectively. Among intervention types that can be mimicked by MR, only trials of pharmaceutical interventions could be automatically matched to MR results due to insufficient annotation with MeSH ontology. A manual survey of the literature highlighted the potential for triangulation across a number of exposure/outcome pairs if these challenges can be addressed. We conclude that careful triangulation of MR with RCT evidence should involve consideration of similarity of phenotypes across study designs, intervention intensity and duration, study population demography and health status, comparator group, intervention goal and quality of evidence.

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Are vitamins relevant to cancer risks? A Mendelian randomization investigation

Cited by 14 publications

References 31 publications

B Vitamins and Their Role in Immune Regulation and Cancer

B Vitamins and Their Role in Immune Regulation and Cancer

Associations between potential causal factors and colorectal cancer risk: A systematic review and meta‐analysis of Mendelian randomization studies

Systematic comparison of Mendelian randomization studies and randomized controlled trials using electronic databases

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