The clinical significance in healthy men of the association between obesity related plasma hemodilution and tumor marker concentration.

PURPOSE

We investigated the association between body mass index and the concentration of tumor markers including carcinoembryonic antigen, alpha-fetoprotein, the carbohydrate antigen 19-9 and prostate specific antigen, as well as the association between body mass index changes and tumor marker concentration changes in a population of healthy men.

MATERIALS AND METHODS

We evaluated data on 8,776 men screened for tumor markers (carcinoembryonic antigen, alpha-fetoprotein, carbohydrate antigen 19-9 and prostate specific antigen) at least 3 times annually during an annual examination from 2001 to 2007. We assessed the tumor marker test findings for a trend in the age, alanine aminotransferase and creatinine adjusted tumor marker concentration by body mass index. We used multivariate regression analysis to determine whether a change in body mass index was associated with a tumor marker concentration change over time using calculated tumor markers, body mass index, creatinine and alanine aminotransferase concentration change per year.

RESULTS

After adjusting for age, creatinine and alanine aminotransferase a higher body mass index was associated with lower prostate specific antigen (p for trend <0.001), carcinoembryonic antigen (p for trend <0.001) and carbohydrate antigen 19-9 (p for trend <0.001). On multivariate regression analysis each 1 kg/m(2) of body mass index gain per year was associated with a -0.011 ng/ml change in prostate specific antigen concentration, a -0.030 ng/ml change in carcinoembryonic antigen concentration and a -0.192 IU/ml change in carbohydrate antigen 19-9 concentration per year.

CONCLUSIONS

In this cohort of healthy men hemodilution from increased plasma volume may be responsible for the observed decreased tumor marker concentration in men with a higher body mass index. In addition, an increase in body mass index may predict a lower tumor marker concentration in an individual.