title: Relationship between prostate-specific antigen and obesity in prostate cancer screening: analysis of a large cohort in Japan.
abstract: Previous studies have shown that lower prostate-specific antigen (PSA) levels in obese men might decrease the sensitivity of prostate cancer screening, leading to delayed diagnosis and unfavorable prognosis. We examined whether the effect of obesity is important in prostate cancer screening of Japanese men, who have a low prevalence of obesity. We analyzed 19,294 male subjects from a large cohort of Toyota Motor Corporation (TMC) employees (aged > 50 years, serum PSA level ≤ 4.0 ng/mL) who underwent physical examinations from August 2006 to December 2009. The relationship between PSA level and obesity-related factors was analyzed by simple and multiple regression analysis. The relationships between six body mass index (BMI) categories, and PSA level and PSA mass (PSA concentration × plasma volume) were analyzed. PSA level decreased significantly with increasing BMI, but the coefficient of determination was very low. Mean PSA values decreased from 1.02 to 0.85 ng/mL as BMI increased from underweight (BMI <18.5) to morbidly obese (BMI >35). However, PSA mass peaked in the overweight category and was slightly reduced with increasing BMI. On multiple regression analysis, PSA level was influenced by age, diastolic blood pressure and high-density lipoprotein as well as BMI. We found an inverse but weak relationship between PSA level and BMI. Obesity seems to have very limited influence on prostate cancer screening in this population. Nonetheless, when considering indications for prostatic biopsy in obese men, we should be aware that the hemodilution effect might reduce PSA levels.
authors.affiliation: Department of Urology, Toyota Memorial Hospital, Toyota, Aichi, Japan. yasuaki_kubota@mailtoyota.co.jp
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Kubota
authors.forename: Kensaku
authors.initials: K
authors.lastname: Seike
authors.forename: Shinichi
authors.initials: S
authors.lastname: Maeda
authors.forename: Yuka
authors.initials: Y
authors.lastname: Shinohara
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Iwata
authors.forename: Norio
authors.initials: N
authors.lastname: Sugimoto
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D015992:Body Mass Index; D015331:Cohort Studies; D006801:Humans; D007564:Japan; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis; D012044:Regression Analysis
chemical_list: D017430:Prostate-Specific Antigen