Bilirubin, the primary end product of heme catabolism, is a key marker of liver and hematological disorders, and important cytoprotective properties have been ascribed to this bile pigment.
Stephen Zucker, Paul Horn and Kenneth Sherman from Cincinnati,Ohio analyzed the 'Third National Health and Nutrition Examination Survey' of health and nutrition in the United States, in order to determine the demographics and correlates of serum bilirubin levels in the general population.
The researchers studied a total of 176,748,462 subjects, including men and women aged 17 and older.
Researchers analyzed the data and revealed that the mean serum total bilirubin in the adult population is 0.62 ± 0.003 mg/dL (SEM), with a 97.5% cut-off of 1.4 mg/dL.
|Bilirubin concentrations are unrelated to body weight but are reduced in smokers|
They also found that serum bilirubin levels are significantly higher in men than in women and are lower in non-Hispanic blacks compared with non-Hispanic whites and Mexican Americans.
The researchers found that bilirubin concentrations are unrelated to body weight but are reduced in active smokers.
The group found that individuals with a history of nondermatological malignancy were found to exhibit significantly lower serum bilirubin concentrations compared with those who do not have a history of nondermatological cancer.
In particular, each 1-mg/dL increase in serum bilirubin is associated with a markedly decreased prevalence of colorectal cancer.
Dr Zucker concluded, "Serum bilirubin levels vary significantly with gender, race, and smoking status."
He added that, "As we have seen an inverse correlation between serum bilirubin concentrations and history of nondermatological malignancy, particularly colorectal cancer, there should be further investigations into the potentially important chemopreventive function of bilirubin."