Chen C B, Eurich D T, Majumdar S R, Johnson J A
School of Public Health, University of Alberta, Edmonton, AB, Canada.
Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada.
Prostate Cancer Prostatic Dis. 2017 Mar;20(1):122-126. doi: 10.1038/pcan.2016.65. Epub 2017 Jan 10.
Men with diabetes may have a lower risk of prostate cancer than men without diabetes which may be altered by metformin use or race/ethnicity.
Using administrative databases, from 1994 to 2012, adult (age⩾50 years) men with diabetes were identified. Metformin exposure was defined as a time-dependent variable, stratified first into any use, and into tertiles of cumulative dose. Surname algorithms identified individuals as Chinese or non-Chinese. Multivariable Cox regression estimated the risk of prostate cancer.
The cohort of 80 001 had a mean age of 64 years and median follow-up of 9 years. Chinese users of metformin aged 50-59, 60-69 and ⩾70 had similar risks of prostate cancer as non-users. Non-Chinese users aged 50-59 (adjusted hazards ratio (aHR): 0.86, 0.74 to 1.00) had a decreased risk whereas men aged 60-69 and ⩾70 did not. However, when metformin exposure was stratified into tertiles, there was no association in any strata except non-Chinese men aged 50-59 in the first (aHR: 0.68, 95% confidence interval (CI): 0.55, 0.84), second (aHR: 0.75, 95% CI: 0.61, 0.92) and third (aHR: 0.79, 95% CI: 0.64, 0.96) tertiles of metformin exposure and non-Chinese men aged 60-69 in the first (aHR: 0.81, 95% CI: 0.68, 0.95) tertiles of metformin exposure.
There was no clear association between metformin and risk of prostate cancer in men with diabetes in either race/ethnicity. Our findings suggest a consistent relationship between metformin and prostate cancer across race/ethnicity.
糖尿病男性患前列腺癌的风险可能低于非糖尿病男性，而这种情况可能会因使用二甲双胍或种族/民族而改变。
利用行政数据库，在1994年至2012年期间，识别出成年（年龄≥50岁）糖尿病男性。二甲双胍暴露被定义为一个随时间变化的变量，首先分为是否使用，然后分为累积剂量的三分位数。姓氏算法将个体识别为华裔或非华裔。多变量Cox回归估计前列腺癌的风险。
80001名队列成员的平均年龄为64岁，中位随访时间为9年。50 - 59岁、60 - 69岁和≥70岁的华裔二甲双胍使用者患前列腺癌的风险与非使用者相似。50 - 59岁的非华裔使用者（调整后风险比（aHR）：0.86，0.74至1.00）患前列腺癌的风险降低，而60 - 69岁和≥70岁的男性则没有。然而，当将二甲双胍暴露分层为三分位数时，除了50 - 59岁的非华裔男性处于二甲双胍暴露的第一（aHR：0.68，95%置信区间（CI）：0.55，0.84）、第二（aHR：0.75，95% CI：0.61，0.92）和第三（aHR：0.79，95% CI：0.64，0.96）三分位数以及60 - 69岁的非华裔男性处于二甲双胍暴露的第一（aHR：0.81，95% CI：0.68，0.95）三分位数外，其他各层均无关联。
在糖尿病男性中，无论种族/民族，二甲双胍与前列腺癌风险之间均无明确关联。我们的研究结果表明，二甲双胍与前列腺癌在不同种族/民族之间存在一致的关系。
