However, the news has not been uniformly positive. Several other studies on the subject have failed to detect a significant association between GS and CVD.[10, 15-20] A recent, large meta-analysis of 11 studies with 14 711 cases and 60 324 controls, including eight previously published studies and three Mendelian randomization studies undertaken by

the authors of this meta-analysis, examined the relationship of risk of various CVDs with three polymorphism sites related to the UGT1A1 gene.[21] In this analysis, homozygous carriers of the variants associated with increased bilirubin (UGT1A1*28/UGT1A1*28 genotype, rs887829 AA, or rs6742078 TT) showed no reduction in risk of various ischemic CVDs taken together (odds ratio = 1.01, 95% CI = 0.88–1.16) BAY 73-4506 cell line compared to heterozygotes and noncarriers.[21]

Moreover, in another study, GS genotype has shown no association with the severity of CAD.[22] Interestingly, our search in the database of human genome-wide association studies[23] failed to show any association of coronary heart disease with genetic markers located on the segment of the long Erlotinib research buy arm of chromosome 2, where UGT1A1 gene is located. This provides an important piece of evidence against association of GS with CAD, since the genome-wide studies on the subject have been quite large. Relationship of GS with other diseases besides CVD, such as cancers and chronic diseases, has also been studied. These studies have found a negative association between the presence Protein tyrosine phosphatase of UGT1A1*28 allele or high serum bilirubin and risk of endometrial[24]

and colon cancers.[25] Protective effects of GS against the occurrence of diabetes[26] and rheumatoid arthritis[27] have also been reported. The study by Horsfall et al. in the previous of the Journal, had several positive features, including a “cohort” study design and a large sample size. Further, the outcome assessed was all-cause death rate, whereas most of the previous studies among healthy persons had focused on CVD. All-cause death rate has the advantage of aggregating the effects of the factor under study on several disease processes (e.g. on CVD, malignant diseases, cerebrovascular accidents, infections, etc.). This obviates the possibility of the factor providing benefit against one disease while simultaneously increasing the risk of other diseases, wherein the harms may outweigh the benefits. Also, mortality is a hard endpoint that does not suffer from ascertainment bias. Thus, all-cause mortality provides a clinically relevant, reliable and preferred endpoint. However, it would have been useful if the authors had, in addition, provided data on cause-specific and age-specific mortality rates in the GS and non-GS groups. Such disaggregated data would have helped us identify the causes of death that are most influenced by the presence of GS. The study design did have some limitations.