Автор: Metachronous colorectal adenoma (perennial adenoma)
To our knowledge, no previous study has prospectively evaluated the associations of calcium intake with incident adenoma, metachronous adenoma, and incident cancer in the same cohort using the same food frequency questionnaire, which minimises misclassification that can occur when combining dietary estimates from multiple studies with different food frequency questionnaire instruments. One weakness is that the PLCO is a sigmoidoscopy-based randomised trial, which only screened the distal colorectal region. Thus, incident adenoma cases mainly included adenomas from the left side of the bowel although metachronous adenoma and incident CRC cases included cases from both proximal and distal regions. However, it is interesting that reports found that colonoscopy was linked to reduced deaths from the distal colorectal region, but not the right. 41,42 Similarly another report from the PLCO observed sigmoidoscopic screenings only reduced distal, but not proximal CRC mortality. 25 Further, sigmoidoscopic screenings also significantly reduced both distal and proximal CRC incidence in the PLCO. 25 Thus, the PLCO provides a unique opportunity to test whether calcium intake confers additional protection against proximal and distal CRC among those receiving sigmoidoscopic screening(s). Similar to other nutritional epidemiological studies using food frequency questionnaires, there are possibly non-differential measurement errors which usually bias the results to the null. In addition, despite the relatively large sample sizes in our study, our investigations between calcium intake and colorectal carcinogenesis were constrained when evaluating by Ca:Mg ratio strata. The number of cases for some sub-categories of calcium intake in the <1.7 Ca:Mg ratio stratum were few and in some instances zero, making inferences relating to trends difficult in this stratum. Furthermore, to maintain relatively balanced number of cases in calcium categories in the largest Ca:Mg ratio stratum, we choose 2.5, the median in the data set, as one of the Ca:Mg ratio cut-offs, instead of 2.6 as investigated in previous studies. Finally, considering investigation of three main outcomes, several sub-group analyses and tests for effect modification, it is possible that findings reported in this study may be due to chance. We found different calcium intake distribution between intervention arm and control arm shown in Supplementary Table 1. The reason is not clear, and it may be due to different food frequency questionnaires were in two arms. However, we found the association pattern between calcium intake and CRC risk is similar in the intervention arm and control arm.
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The outcomes from our data have contract with before wrote studies, in disagreement with others. One another cohort training and you may prior to intervention products found higher calcium supplements intake or supplements was linked to moderately smaller risks of adenoma, metachronous adenoma and you can CRC. seven,8,9,ten,11,12,15,thirty two Yet not, the outcome of a large-scale randomised clinical test (WHI) do not support an aftereffect of calcium supplements and additionally vitamin D supplements on the occurrence out of CRC shortly after seven numerous years of pursue-right up. sixteen It will be possible your pursue-up period within the WHI might not have become for enough time getting a safety impact are evident. Indeed, the research of the Nurses’ Health Investigation and you may Health professionals Realize-right up Research not just showed an inverse association between calcium supplements consumption and you can CRC as well as revealed that the fresh associations became more and more stronger with increasing episodes out of latency, and try strongest towards twelve–sixteen ages go after-upwards period. 33 That have the common follow-right up period significantly more along these lines investigation compared to the WHI, we also statement equivalent area prices since Zhang ainsi que al., having a healthier inverse relationship to own distal CRC although not getting proximal CRC. 33 A sites de rencontre professionnels mГ©dicaux beneficial pooled-research off ten cohort knowledge in addition to stated the inverse organization anywhere between dairy and you can CRC is actually simply for disease of your distal, maybe not the fresh proximal anus. fifteen Therefore racking up facts consistently implies calcium supplements intake are with the faster threat of distal CRC.
It’s distinguished that in case we evaluated the fresh combined contacts out-of California intake which have Milligrams intake categorised from the RDA top for three different varieties of colorectal neoplasia exposure (event adenoma, incident CRC or event distal CRC), i receive equivalent styles such as the no. 1 analyses where in fact the inverse connectivity getting California intake in relation to such outcomes was in fact the healthier to own Milligrams intake in the otherwise above the RDA opposed to Mg intake lower than the new RDA (Additional Tables cuatro–6). But not, none of your tests having correspondence was basically statistically high having said that to the screening for telecommunications we noticed towards the California:Milligrams percentages. This is certainly in line with previous conclusions for the Eastern Asian communities during the that interactions had been statistically tall between Ca:Milligrams percentages with calcium consumption, yet not anywhere between magnesium consumption with calcium consumption. 19 Simply put, the communication that have Ca:Mg percentages cannot be said of the magnesium intake by yourself.
