Instrumental Variable Estimation of the Causal Effect of Plasma 25-Hydroxy-Vitamin D on Colorectal Cancer Risk: A Mendelian Randomization Analysis

ABSTRACTObjectivesTo assess the association between blood circulating Vitamin D levels and colorectal cancer risk in the Asian population.DesignThis is a systematic review and dose-response meta-analysis of observational studies that investigated the relationship between blood circulating Vitamin D levels and colorectal cancer risk in the Asian population.Data SourcesRelevant studies were identified through a literature search in MEDLINE, EMBASE, and Web of Science from January 1980 to 31 January 2019. Eligibility criteria: original studies published in peer-reviewed journals investigating the association between blood circulating Vitamin D levels and the risk of colorectal cancer and/or adenoma in Asian countries.Data extraction and synthesisTwo authors independently extracted data and assessed the quality of included studies. Study-specific ORs were pooled using a random-effects model. A dose-response meta-analysis was performed with generalized least squares regression. We applied the Newcastle-Ottawa Scale quality assessment to evaluate the quality of the selected studies.ResultsThe eight included studies encompassed a total of 2,916 cases and 6,678 controls. The pooled ORs of colorectal cancer for the highest versus lowest categories of blood circulating Vitamin D levels was 0.75 [95% CI, 0.58-0.97] up to 36.5 ng/mL in the Asian population. There was heterogeneity among the studies (I2=53.9%, Pheterogeneity=0.034). The dose-response meta-analysis indicated a significant linear relationship (Pnon-linearity=0.11). An increment of 16 ng/mL in blood circulating Vitamin D level corresponded to an OR of 0.79 [95% CI, 0.64-0.97].ConclusionsThe results of this meta□analysis indicate that blood circulating Vitamin D level is associated with decreased risk of colorectal cancer in Asian countries. The dose-response meta-analysis shows that the strength of this association among the Asian population is similar to that among the Western population. Our study suggests that the Asian population should improve nutritional status and maintain a higher level of blood circulating Vitamin D.Strengths and limitations of this studyOur study seeks to extend previous work by including a number of new studies and by distinguishing the Asian population explicitly.The number of included studies is not sufficient to provide a robust estimate, so the results should be interpreted in the context of the limitations of the available data.Heterogeneous definitions of blood circulating Vitamin D categories were used across studies. The variability in definitions could limit comparability between studies.Our study included seven case-control studies; the study design implies that the measurement of blood circulating Vitamin D is measured in individuals already diagnosed with colorectal cancer. Results from case-control studies need to be interpreted cautiously because of the potential for reverse causation.Time of blood sampling in relation to outcome ascertainment also varied among studies. Such cross-sectional measurements may not accurately reflect an individual’s Vitamin D status across time.

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Abstract 626: Association of circulating vitamin D concentrations with colorectal cancer risk differs depending on inherited genotypes in combination with dietary lifestyle factors

10.1158/1538-7445.am2019-626 ◽

2019 ◽

Author(s):

David C. Gibbs ◽

Marjorie L. McCullough ◽

Mingyang Song ◽

Caroline Y. Um ◽

Kana Wu ◽

...

Keyword(s):

Colorectal Cancer ◽

Vitamin D ◽

Cancer Risk ◽

Lifestyle Factors ◽

Colorectal Cancer Risk

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Abstract 2361: Mendelian randomization study: The association between metabolic pathways and colorectal cancer risk

10.1158/1538-7445.am2020-2361 ◽

2020 ◽

Author(s):

Su Yon Jung ◽

Jeanette Papp ◽

Eric Sobel ◽

Zuo-Feng Zhang

Keyword(s):

Colorectal Cancer ◽

Cancer Risk ◽

Metabolic Pathways ◽

Mendelian Randomization ◽

Colorectal Cancer Risk

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Associations between dietary vitamin D, calcium and dairy products intakes and colorectal cancer risk: a case-control study in China

Proceedings of The Nutrition Society ◽

10.1017/s0029665120002360 ◽

2020 ◽

Vol 79 (OCE2) ◽

Author(s):

Cai-Xia Zhang ◽

Xin Zhang ◽

Hong Luo ◽

Xiao-Li Feng ◽

Nai-Qi Zhang

Keyword(s):

Colorectal Cancer ◽

Vitamin D ◽

Cancer Risk ◽

Dairy Products ◽

Dietary Calcium ◽

Food Composition ◽

Colorectal Cancer Risk ◽

Dietary Vitamin ◽

Nutrient Intakes ◽

Dietary Vitamin D

AbstractIntroductionThe effect of dietary vitamin D, calcium and dairy products intake on colorectal cancer risk is controversial. This study aims to investigate the associations between dietary vitamin D, calcium, dairy products intake and colorectal cancer risk among Chinese population.Materials and MethodsDuring July 2010 to December 2018, 2380 incident, first primary, histologically confirmed colorectal cancer cases and 2389 sex and age-matched (5-year interval) controls were recruited. Dietary intake information was collected by face-to-face interviews using a validated food frequency questionnaire. Energy and other nutrient intakes such as dietary calcium were computed on the basis of the 2002 Chinese Food Composition Table, and the dietary vitamin D intake was calculated according to the United States Department of Agriculture Food Composition Database. Unconditional multivariable logistic regression models were used to calculate the odds ratios (ORs) and 95% confidence interval (CI) after adjusting for various confounders, including socio-demographic characteristics, lifestyle factors, BMI, family history of cancer, energy intake and several nutrient intakes.ResultsThe energy-adjusted mean dietary vitamin D, calcium and total dairy products intakes were 5.69μg/d, 406.94mg/d, 4.02g/d for cases and 6.81μg/d, 468.21mg/d, 9.50g/d for controls. Compared with the controls, cases had a lower intake of dietary vitamin D, calcium and total dairy (P < 0.001). A higher intake of dietary vitamin D and calcium was found to be associated with 43% and 51% reduction in colorectal cancer. The ORs of the highest quartile compared with the lowest quartile intake were 0.57 (95% CI: 0.46, 0.70, Ptrend < 0.001) for dietary vitamin D and 0.49 (95% CI: 0.39, 0.61, Ptrend < 0.001) for dietary calcium. We observed a statistically significant inverse association of dairy products intake with colorectal cancer risk. Compared with the lowest tertile, the adjusted ORs for the highest tertile were 0.31 (95% CI: 0.26, 0.38, Ptrend < 0.001) for total dairy. The inverse associations of dietary vitamin D, calcium and dairy products intakes with colorectal cancer risk were observed in both men and women, colon and rectal cancer.ConclusionOur study indicated that higher dietary vitamin D, calcium and dairy products intakes were associated with a lower colorectal cancer risk.

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