Gallstones, Body Mass Index, C-Reactive Protein, and Gallbladder Cancer: Mendelian Randomization Analysis of Chilean and European Genotype Data

BACKGROUND AND AIMS

Gallbladder cancer (GBC) is a neglected disease with substantial geographical variability: Chile shows the highest incidence worldwide, while GBC is relatively rare in Europe. Here, we investigate the causal effects of risk factors considered in current GBC prevention programs as well as C-reactive protein (CRP) level as a marker of chronic inflammation.

APPROACH AND RESULTS

We applied two-sample Mendelian randomization (MR) using publicly available data and our own data from a retrospective Chilean and a prospective European study. Causality was assessed by inverse variance weighted (IVW), MR-Egger regression, and weighted median estimates complemented with sensitivity analyses on potential heterogeneity and pleiotropy, two-step MR, and mediation analysis. We found evidence for a causal effect of gallstone disease on GBC risk in Chileans (P = 9 × 10-5 ) and Europeans (P = 9 × 10-5 ). A genetically elevated body mass index (BMI) increased GBC risk in Chileans (P = 0.03), while higher CRP concentrations increased GBC risk in Europeans (P = 4.1 × 10-6 ). European results suggest causal effects of BMI on gallstone disease (P = 0.008); public Chilean data were not, however, available to enable assessment of the mediation effects among causal GBC risk factors.

CONCLUSIONS

Two risk factors considered in the current Chilean program for GBC prevention are causally linked to GBC risk: gallstones and BMI. For Europeans, BMI showed a causal effect on gallstone risk, which was itself causally linked to GBC risk.

ABCB1/4 gallbladder cancer risk variants identified in India also show strong effects in Chileans

BACKGROUND

The first large-scale genome-wide association study of gallbladder cancer (GBC) recently identified and validated three susceptibility variants in the ABCB1 and ABCB4 genes for individuals of Indian descent. We investigated whether these variants were also associated with GBC risk in Chileans, who show the highest incidence of GBC worldwide, and in Europeans with a low GBC incidence.

METHODS

This population-based study analysed genotype data from retrospective Chilean case-control (255 cases, 2042 controls) and prospective European cohort (108 cases, 181 controls) samples consistently with the original publication.

RESULTS

Our results confirmed the reported associations for Chileans with similar risk effects. Particularly strong associations (per-allele odds ratios close to 2) were observed for Chileans with high Native American (=Mapuche) ancestry. No associations were noticed for Europeans, but the statistical power was low.

CONCLUSION

Taking full advantage of genetic and ethnic differences in GBC risk may improve the efficiency of current prevention programs.

Complications of robotic foregut surgery: risks and advantages

INTRODUCTION

Laparoscopic foregut surgeries are highly complex procedures that carry a high potential for morbidity and mortality should complications should occur. The robotic-assisted platform offers improved visualization of anatomy, optimal fine motor control, and a higher degree of instrumentation range of motion, which may potentially lead to better outcomes. This paper reviews the risks and benefits of the robotic platform in foregut procedures.

EVIDENCE ACQUISITION

A web-based literature search was performed, in August 2016 using Pubmed, EMBASE, and Google Scholar from cited English publications from 1996 to 2016. We included randomized control trials, non-randomized comparison studies, and cohort studies in robotic foregut surgery. Abstracts, letters, editorials, expert opinions, review papers, and meta-analyses with no original statistical analyses were not included.

EVIDENCE SYNTHESIS

A total of 619 articles were identified of which 98 articles met the inclusion criteria. The studies were divided into areas of benign and malignant foregut procedures that utilized robotic assistance. Intraoperative complications related to both the surgery itself as well as robotic hardware malfunction, short-term and long-term clinical outcomes were extracted.

CONCLUSIONS

Intraoperative and postoperative complications of robotic assistance during foregut surgery are comparable or superior to those of traditional laparoscopic techniques. Our review suggests improved outcomes in Heller myotomies, gastrectomies, and esophagectomies.

No evidence for an association between genetic polymorphisms of beta(2)- and beta(3)-adrenergic receptor genes with body mass index in Aymara natives from Chile

OBJECTIVE

We assessed the association between Gln27Glu and Trp64Arg genetic polymorphisms of the beta(2) (ADRB2) and beta(3) (ADRB3) adrenergic receptor genes with body mass index and other cardiovascular risk factors.

METHODS

In a cross-sectional study, adult Aymara subjects (n = 152) living in the Andean regions of northern Chile were characterized with respect to their ADRB2 and ADRB3 genotypes, body mass index, plasma leptin and insulin levels, fasting glucose concentration, blood pressure, and plasma lipid profile.

RESULTS

The frequency of the Glu27 allele of the ADRB2 gene was estimated to be 0.04, and the allele frequency of the Arg64 variant of the ADRB3 gene was estimated as 0.13. No associations were found between the Trp64Arg polymorphism of the ADRB3 gene and body mass index or other cardiovascular risk factors. The small number of subjects with the allele encoding Glu27 in the ADRB2 gene seriously limited the analysis of the association between genotype and phenotype with the use of this polymorphism, although no clear associations were found.

CONCLUSION

We found insufficient evidence to support an association between polymorphisms Gln27Glu and Trp64Arg of the ADRB2 and ADRB3 genes, respectively, with body mass index and other cardiovascular risks in the rural Aymara population from Chile.