Freedland Stephen J, Platz Elizabeth A, Presti Joseph C, Aronson William J, Amling Christopher L, Kane Christopher J, Terris Martha K
Department of Urology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
J Urol. 2006 Feb;175(2):500-4; discussion 504. doi: 10.1016/S0022-5347(05)00162-X.
Obesity has been associated with lower serum testosterone, theoretically resulting in decreased PSA production. Obesity has also been associated with prostatic enlargement, making the detection of existent cancer more difficult. Together these findings would result in an apparent protective effect of obesity on prostate cancer risk due to technical detection issues unrelated to cancer biology. We examined the association between BMI, and PSA and prostate weight in a cohort of men undergoing RP.
We evaluated the association of BMI with prostate weight and PSA using linear regression, adjusting for patient age at RP, year of RP, race, and pathological stage and grade in 1,414 men treated with RP between 1988 and 2004 at the 5 equal access medical centers that comprise the Shared Equal Access Regional Cancer Hospital Database.
On multivariate analysis increasing BMI was associated with increasing prostate weight but only in men younger than 63 years and not in men 63 years or older (p-trend <0.001 and 0.44, respectively). In men younger than 63 years mean multivariate adjusted prostate weight +/- SE in those with a BMI of less than 25 vs 30 to 34.9 kg/m was 33.8 +/- 1.4 vs 41.4 +/- 1.6 gm. There was no significant association between BMI and preoperative PSA (p-trend = 0.70).
In a cohort of men undergoing RP obesity was associated with larger prostate size but only in younger men. There was no association between BMI and PSA. Assuming equal PSA, the degree of prostatic enlargement observed in younger obese men in this study would be expected to result in a modest decrease in the odds of detecting prostate cancer in a contemporary series of PSA screened men due to the decreased sensitivity of cancer detection related to larger prostate size. Obesity may appear protective for prostate cancer in younger men due to technical issues unrelated to cancer biology.
肥胖与血清睾酮水平降低有关，理论上会导致前列腺特异性抗原（PSA）产生减少。肥胖还与前列腺增大有关，使得现有癌症的检测更加困难。综合这些发现，由于与癌症生物学无关的技术检测问题，肥胖对前列腺癌风险会产生明显的保护作用。我们在一组接受根治性前列腺切除术（RP）的男性队列中研究了体重指数（BMI）与PSA及前列腺重量之间的关联。
我们使用线性回归评估BMI与前列腺重量和PSA的关联，并对1988年至2004年期间在构成共享平等获取区域癌症医院数据库的5个平等获取医疗中心接受RP治疗的1414名男性的患者RP时的年龄、RP年份、种族以及病理分期和分级进行了调整。
多因素分析显示，BMI增加与前列腺重量增加相关，但仅在63岁以下男性中如此，在63岁及以上男性中则不然（p趋势分别为<0.001和0.44）。在63岁以下男性中，BMI小于25与30至34.9kg/m²者的多因素调整后平均前列腺重量±标准误分别为33.8±1.4与41.4±1.6克。BMI与术前PSA之间无显著关联（p趋势=0.70）。
在接受RP的男性队列中，肥胖与前列腺体积增大相关，但仅在年轻男性中如此。BMI与PSA之间无关联。假设PSA水平相同，由于与较大前列腺体积相关的癌症检测敏感性降低，在当代一系列PSA筛查男性中，本研究中观察到的年轻肥胖男性前列腺增大程度预计会导致前列腺癌检测几率适度降低。由于与癌症生物学无关的技术问题，肥胖在年轻男性中可能看似对前列腺癌有保护作用。
