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/m2, and 31% had a BMI ≥ 25 kg/m2. 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/m2) 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