[Relationship between serum prostate-specific antigen levels and body mass index in Beijing men over 50 years of age].

OBJECTIVE

To investigate the relationship between body mass index (BMI) and serum prostate specific antigen (PSA).

METHODS

A cross-sectional study was performed at community of Beijing in men over 50 years old. Height, weight and PSA (both serum TPSA and FPSA) were assessed in 1573 men. According to the redefined World Health Organization (WHO) criterion for Asia Pacific Region, BMI was categorized as light weight (BMI < 18.5 kg/m2), normal (18.5 kg/m2 < or = BMI < 23.0 kg/m2), overweight (23.0 kg/m2 < or = BMI < 25.0 kg/m2), obese (25.0 kg/m2 < or = BMI < 30.0 kg/m2) and severe obese (BMI > or = 30 kg/m2). SPSS 13.0 was used in BMI and PSA statistical analysis.

RESULTS

Mean age was (64 +/- 10) years, mean BMI (24 +/- 3) kg/m2, PSA median 1.0 (0.6 - 1.9) microg/L and mean prostate volume(30 +/- 18) ml. BMI classification: low weight 54 cases (3.43%), normal weight 441 (28.04%), overweight 423 patients (26.89%), obesity 597 patients (37.95%) and severe obesity 58 (3.69%). We adjusted the low weight group and severe obesity group into normal group and obesity group respectively for small sample capacity. After adjustment, there was no significance difference (P = 0.75) between PSA level of normal group and that of obesity group. However, the PSA level of normal group and overweight group versus obesity group respectively, there were significant differences (P = 0.002, 0.010). After adjusting for age and prostate volume, the correlation between BMI and PSA was negative. BMI showed no significant correlation with PSA in different age groups.

CONCLUSION

BMI and PSA were negatively correlated. BMI should be considered as a factor (esp. for obese or severe obese) in man undergoing prostate cancer screening.