Serum adiponectin concentration in 2,939 Japanese men undergoing screening for prostate cancer

BACKGROUND Recent investigations suggest that serum adiponectin levels are negatively associated with the development of aggressive prostate cancer, however, not all epigenetic studies support the inverse association. METHODS We analyzed serum adiponectin levels, prostate-specific antigen (PSA) levels, and outcomes of prostate cancer screening of 2,939 participants of a PSA-based screening program conducted by a single institute in Japan. RESULTS The median body mass index (BMI) of the participants was 23.9 kg/m(2), and 31% had a BMI ≥ 25 kg/m(2). The adiponectin levels were significantly and negatively correlated with BMI (r =  -0.260, P < 0.0001). However, a significant and positive correlation was observed between adiponectin levels and PSA levels (r = 0.054, P = 0.0061). After screening, 24 (0.82%) patients were diagnosed with prostate cancer. Interestingly, the adiponectin levels of the 24 prostate cancer patients (average 9.86 μg/mL) were significantly higher than those of the 2,817 participants with PSA levels < 4 ng/mL (average 7.63 μg/mL) (P = 0.0049). However, when restricted to the eight high-risk prostate cancer patients, the adiponectin levels did not differ from those of the participants with PSA levels < 4 ng/mL. The age-adjusted cancer detection rate of the participants was calculated by stratifying the BMI (cut-off level 25 kg/m(2)) and adiponectin levels (cut-off level 6.7 μg/mL). The cancer detection rate in the high-BMI and high-adiponectin group was 1.67%, which was the highest among all groups. CONCLUSIONS There was a significant positive correlation between adiponectin levels and PSA levels. The present findings also suggest that the incidence of low- or intermediate-risk prostate cancer might be increased in overweight men with high serum adiponectin levels.