A causal link between alcohol consumption and colorectal cancer (CRC) was established only recently by the International Agency for Research on Cancer. However, the quantitative association between alcohol drinking and CRC mortality is still an open question. We performed a systemic review and meta-analysis on epidemiological studies to quantify the risk for CRC mortality at different levels of alcohol consumption. A literature search was carried out in PubMed and Web of Science to identify all relevant studies published from January 1966 to June 2013. The pooled relative risk (RR) and the corresponding 95% confidence interval (CI) were estimated by categorical meta-analysis. A dose-risk relation was also analyzed. Nine cohort studies exploring the association between CRC mortality and alcohol drinking were identified. Compared with non/occasional drinkers, the pooled RR was 1.03 (95% CI, 0.93-1.15) for any, 0.97 (95% CI, 0.86-1.10) for light (≤12.5 g/day of ethanol), 1.04 (95% CI, 0.94-1.16) for moderate (12.6-49.9 g/day of ethanol), and 1.21 (1.01-1.46) for heavy drinkers (≥50 g/day of ethanol). For heavy drinkers, the pooled estimate was apparently higher for men (RR=1.28; 95% CI, 1.13-1.46) than for women (RR=0.79; 95% CI, 0.40-1.54; P(heterogeneity)=0.007). The dose-response analysis showed a J-shaped relationship between alcohol consumption and CRC mortality. The present meta-analysis provides the evidence for an association between heavy alcohol drinking (≥50 g/day of ethanol) and CRC mortality.

BackgroundMicroRNAs (miRNAs) negatively regulate the gene expression and act as tumor suppressors or oncogenes in oncogenesis. The association between single nucleotide polymorphism (SNP) in miR-196a2 rs11614913 and the susceptibility of digestive system cancers was inconsistent in previous studies.Methodology/Principal FindingsAn updated meta-analysis based on 15 independent case-control studies consisting of 4999 cancer patients and 7606 controls was performed to address this association. It was found that miR-196a2 polymorphism significantly elevated the risks of digestive system cancers (CT vs. TT, OR = 1.25, 95% CI = 1.07–1.45; CC vs. TT, OR = 1.38, 95% CI = 1.13–1.67; CC/CT vs. TT, OR = 1.29, 95% CI = 1.10–1.50; CC vs. CT/TT, OR = 1.14, 95% CI = 1.01–1.30; C vs. T, OR = 1.15, 95% CI = 1.05–1.26). We also found that variant in miR-196a2 increased the susceptibility of colorectal cancer (CRC) (CT vs. TT, OR = 1.23, 95% CI = 1.04–1.44; CC vs. TT, OR = 1.32, 95% CI = 1.08–1.61; CC/CT vs. TT, OR = 1.25, 95% CI = 1.07–1.46; C vs. T, OR = 1.15, 95% CI = 1.05–1.28), while the association in recessive model (CC vs. CT/TT, OR = 1.16, 95% CI = 0.98–1.38) showed a marginal significance. Additionally, significant association between miR-196a2 polymorphism and increased risk of hepatocellular cancer (HCC) was detected. By stratifying tumors on the basis of site of origin, source of controls, ethnicity and allele frequency in controls, elevated cancer risks were observed.Conclusion/SignificanceOur findings suggest the significant association between miR-196a2 polymorphism and increased susceptibility of digestive system cancers, especially of CRC, HCC and Asians. Besides, C allele may contribute to increased digestive cancer risks.

The coronavirus disease (COVID-19) has become a global public health threaten. A series of strict prevention and control measures were implemented in China, contributing to the improvement of air quality. In this study, we described the trend of air pollutant concentrations and the incidence of COVID-19 during the epidemic and applied generalized additive models (GAMs) to assess the association between short-term exposure to air pollution and daily confirmed cases of COVID-19 in 235 Chinese cities. Disease progression based on both onset and report dates as well as control measures as potential confounding were considered in the analyses. We found that stringent prevention and control measures intending to mitigate the spread of COVID-19, contributed to a significant decline in the concentrations of air pollutants except ozone (O 3 ). Significant positive associations of short-term exposure to air pollutants, including particulate matter with diameters ≤2.5μm (PM 2.5 ), particulate matter with diameters ≤10μm (PM 10 ), and nitrogen dioxide (NO 2 ) with daily new confirmed cases were observed during the epidemic. Per interquartile range (IQR) increase in PM 2.5 (lag0-15), PM 10 (lag0-15), and NO 2 (lag0-20) were associated with a 7% [95% confidence interval (CI): (4 - 9)], 6% [95% CI: (3 - 8)], and 19% [95% CI: (13 - 24)] increase in the counts of daily onset cases, respectively. Our results suggest that there is a statistically significant association between ambient air pollution and the spread of COVID-19. Thus, the quarantine measures can not only cut off the transmission of virus, but also retard the spread by improving ambient air quality, which might provide implications for the prevention and control of COVID-19.

This meta-analysis confirms the health hazards of heavy drinking (≥50 g/day) and benefits of light drinking (≤12.5 g/day). Large-sample, well-designed, prospective epidemiological studies, especially on heavy drinking among women, should be developed in future.