Association of Circulating 25-Hydroxyvitamin D Levels with Colorectal Cancer: An Updated Meta-Analysis

Abstract

A higher serum 25-hydroxyvitamin D (25(OH)D) concentration benefits colorectal cancer prevention. However, whether it can improve the prognosis among patients is still under discussion. This study aims to explore the impacts of high level 25(OH)D on the survival of colorectal cancer patients. PubMed, Embase, and Cochrane were searched from January 2000 to August 2017 for relevant articles. Only published studies focusing on the relationship between 25(OH)D levels at or near the time of diagnosis and survival were considered. Two review authors independently assessed the risk of bias for each study, and any disagreement was resolved by discussion or by involving a third assessor. Eleven studies comprising 7,367 patients were included. In these studies, there were considerable differences between the higher 25(OH)D level group and the lower group in terms of overall survival (OS), progression-free survival (PFS) and colorectal cancer-specific survival (CSS) in a random effect model (OS: HR 0.67, 95% CI 0.56-0.80, p,0.00001; CSS: HR 0.73, 95% CI 0.55-0.97, p50.03; PFS: HR 0.74, 95% CI 0.61-0.90, p50.003). Moreover, the combined hazard ratios of OS and CSS had considerably significant heterogeneity which may be explained by subgroup analysis. The relationship between 25(OH)D and tumor characteristics/lifestyle factors was also included in the meta-analysis. BMI (p50.03), smoking (p50.03) and physical activity (p50.002) seemed to be associated with circulating 25(OH)D level. Publication bias was undetected. Colorectal cancer patients with higher circulating 25(OH)D level may have a better prognosis.

Low circulating 25-hydroxyvitamin D level is associated with increased colorectal cancer mortality: a systematic review and dose–response meta-analysis

“…As for staging, TNM staging remained a strong tool for establishing prognosis and directing therapy [ 62 ]. No significant heterogeneity among the studies was found for CRC-specific survival in our study ( I 2 = 0%), which was similar to the results of Maalmi et al However, the meta-analysis conducted by Xu et al, showed a significant heterogeneity ( I 2 = 69%), which might because of less studies they included [ 30 ].…”

“…The HR (95% CI) for overall and CRC-specific survival in CRC patients from our study was similar to the previous meta-analyses [ 29 , 30 ]. However, our study showed a lower heterogeneity for overall survival than those in the two meta-analyses.…”

“…Many systematic reviews also showed the effect of 25(OH)D on cancer prognosis [ 58 , 59 ]. There were also some meta-analyses focused on the impact of 25(OH)D on the prognosis of colorectal cancer [ 29 , 30 , 60 , 61 ]. However, some of the meta-analyses were only included a limited number of studies [ 29 , 30 , 61 ].…”

“…There were also some meta-analyses focused on the impact of 25(OH)D on the prognosis of colorectal cancer [ 29 , 30 , 60 , 61 ]. However, some of the meta-analyses were only included a limited number of studies [ 29 , 30 , 61 ]. In addition, quantitative analysis results were not given in some meta-analysis [ 60 ].…”

“…At present, most literatures focused on the relationship between vitamin D and the risk of CRC. Although several meta-analysis of prospective studies have summarized the association between blood 25(OH)D concentrations and survival in patients with CRC [ 29 , 30 ]. However, due to the small numbers of studies and patients included.…”