Influence of Body Mass Index on Serum Prostate Specific Antigen in Males of 40 Years and Above in Lagos Nigeria

Abstract

Background: Prostate cancer is the commonest type of cancer in men aged 40 years and above. Serum Prostate Specific Antigen (PSA) is a widely used analytical test for screening, detection, staging and monitoring of response to treatment of prostate cancer. Studies from Caucasians have shown that increased Body Mass Index (BMI) can potentially lower PSA values, thereby masking clinically significant prostate cancer and delaying effective treatment.

Objective: To determine the relationship between levels of serum prostate specific antigen and Body Mass Index in males of age 40 years and above in Lagos.

Materials/Patients and Methods: This study is a cross-sectional study carried out on randomly selected 130 Nigerian men living in Lagos between the ages of 40 and 80 years. After a 10 hour fast, blood samples were collected from each subject before lOam for serum total PSA assay. Quantitative determination of PSA in serum was done using an enzyme linked immunosorbent assay (ELISA) method. BMI in kg/m- was obtained using weight and height of study subjects.

Results: There was a statistically significant difference between the mean PSA in the obese BMI and normal BMI groups (p= 0.039), values being 0.88 ng/ml and 1.07 ng/ml respectively. There was a statistically significant (p= 0.032) negative correlation between serum Total PSA and BMI of subjects used for the study (r = -0.26).

Conclusion: There was a significant negative correlation between serum Total PSA and BMI of study subjects. The upper limit of the reference interval for serum total PSA in obese subjects is significantly lower than that of normal weight subjects.