Department of Hygiene and Public Health, Teikyo University School of Medicine, Tokyo, Japan.
J Urol. 2010 Apr;183(4):1349-53. doi: 10.1016/j.juro.2009.12.019. Epub 2010 Feb 19.
Several studies show that prostate specific antigen inversely correlates with body mass index. Hemodilution may be responsible for the lower prostate specific antigen in obese men. Hematocrit is the most popular indicator of plasma volume. We examined the effect of hematocrit changes on prostate specific antigen in healthy men during 2 years. We also investigated the association between prostate specific antigen and plasma volume changes based on combined changes in body weight and hematocrit.
We reviewed the records of 8,338 men who visited our institution for routine health assessments in 2005, 2006 and 2007. Using the combination of body weight and hematocrit changes in 1 year we defined hemodilution as weight gain with decreased hematocrit and hemoconcentration as weight loss with increased hematocrit.
On multiple regression analysis controlling for patient age and weight change the hematocrit change was significantly associated positively with the prostate specific antigen change between 2005 and 2006 (1.2%/1 U), and between 2006 and 2007 (0.7%/1 U, each p <0.001). After controlling for age participants with hemoconcentration showed significantly greater prostate specific antigen changes than those with hemodilution, that is 6.1% between 2005 and 2006, and 4.8% between 2006 and 2007 (each p <0.001).
Hematocrit change was positively associated with prostate specific antigen change. Compared to men with hemodilution significantly greater prostate specific antigen changes were observed in men with hemoconcentration. Thus, plasma volume may explain the inverse relationship between body mass index and prostate specific antigen.
几项研究表明，前列腺特异性抗原与体重指数呈负相关。血液稀释可能是肥胖男性前列腺特异性抗原较低的原因。红细胞压积是最常用的血浆容量指标。我们在 2 年内检查了红细胞压积变化对健康男性前列腺特异性抗原的影响。我们还根据体重和红细胞压积的综合变化，研究了前列腺特异性抗原与血浆容量变化之间的关系。
我们回顾了 2005 年、2006 年和 2007 年在我院进行常规健康评估的 8338 名男性的记录。根据 1 年内体重和红细胞压积的变化组合，我们将血液稀释定义为体重增加而红细胞压积降低，血液浓缩定义为体重减轻而红细胞压积增加。
在控制患者年龄和体重变化的多元回归分析中，红细胞压积变化与 2005 年至 2006 年（1.2%/1 U）和 2006 年至 2007 年（0.7%/1 U，均 P <0.001）之间前列腺特异性抗原变化呈显著正相关。在控制年龄后，血液浓缩患者的前列腺特异性抗原变化明显大于血液稀释患者，即 2005 年至 2006 年为 6.1%，2006 年至 2007 年为 4.8%（均 P <0.001）。
红细胞压积变化与前列腺特异性抗原变化呈正相关。与血液稀释患者相比，血液浓缩患者的前列腺特异性抗原变化明显更大。因此，血浆容量可能解释了体重指数与前列腺特异性抗原之间的反比关系。
