PDF(Pubmed)
Abstract：
BACKGROUND: Circulating total insulin-like growth factor-I (IGF-I) is an established risk factor for prostate cancer. However, only a small proportion of circulating IGF-I is free or readily dissociable from IGF-binding proteins (its bioavailable form), and few studies have investigated the association of circulating free IGF-I with prostate cancer risk.
METHODS: We analyzed data from 767 prostate cancer cases and 767 matched controls nested within the European Prospective Investigation into Cancer and Nutrition cohort, with an average of 14-years (interquartile range = 2.9) follow-up. Matching variables were study center, length of follow-up, age, and time of day and fasting duration at blood collection. Circulating free IGF-I concentration was measured in serum samples collected at recruitment visit (mean age 55 years old; standard deviation = 7.1) using an enzyme-linked immunosorbent assay (ELISA). Conditional logistic regressions were performed to examine the associations of free IGF-I with risk of prostate cancer overall and subdivided by time to diagnosis (≤ 14 and > 14 years), and tumor characteristics.
RESULTS: Circulating free IGF-I concentrations (in fourths and as a continuous variable) were not associated with prostate cancer risk overall (odds ratio [OR] = 1.00 per 0.1 nmol/L increment, 95% CI: 0.99, 1.02) or by time to diagnosis, or with prostate cancer subtypes, including tumor stage and histological grade.
CONCLUSIONS: Estimated circulating free IGF-I was not associated with prostate cancer risk. Further research may consider other assay methods that estimate bioavailable IGF-I to provide more insight into the well-substantiated association between circulating total IGF-I and subsequent prostate cancer risk.
METHODS: We analyzed data from 767 prostate cancer cases and 767 matched controls nested within the European Prospective Investigation into Cancer and Nutrition cohort, with an average of 14-years (interquartile range = 2.9) follow-up. Matching variables were study center, length of follow-up, age, and time of day and fasting duration at blood collection. Circulating free IGF-I concentration was measured in serum samples collected at recruitment visit (mean age 55 years old; standard deviation = 7.1) using an enzyme-linked immunosorbent assay (ELISA). Conditional logistic regressions were performed to examine the associations of free IGF-I with risk of prostate cancer overall and subdivided by time to diagnosis (≤ 14 and > 14 years), and tumor characteristics.
RESULTS: Circulating free IGF-I concentrations (in fourths and as a continuous variable) were not associated with prostate cancer risk overall (odds ratio [OR] = 1.00 per 0.1 nmol/L increment, 95% CI: 0.99, 1.02) or by time to diagnosis, or with prostate cancer subtypes, including tumor stage and histological grade.
CONCLUSIONS: Estimated circulating free IGF-I was not associated with prostate cancer risk. Further research may consider other assay methods that estimate bioavailable IGF-I to provide more insight into the well-substantiated association between circulating total IGF-I and subsequent prostate cancer risk.
摘要：
背景：循环总胰岛素样生长因子-I（IGF-I）是前列腺癌的既定危险因素。然而,只有一小部分循环的IGF-I是游离的或容易与IGF结合蛋白（其生物可利用形式）解离，很少有研究调查循环游离IGF-I与前列腺癌风险的关系。
方法：我们分析了来自767例前列腺癌病例和767例配对对照的欧洲癌症和营养队列前瞻性调查的数据。平均14年（四分位距=2.9）随访。匹配变量是研究中心，随访时间，年龄,以及一天中的时间和采血时的禁食持续时间。使用酶联免疫吸附测定（ELISA）测量招募时收集的血清样品中的循环游离IGF-I浓度（平均年龄55岁；标准偏差=7.1）。进行条件逻辑回归以检查游离IGF-I与前列腺癌总体风险的关联，并按诊断时间（≤14和>14年）细分。和肿瘤特征。
结果：循环游离IGF-I浓度（占四分之一，作为连续变量）与前列腺癌总体风险无关（比值比[OR]=1.00每0.1nmol/L增量，95%CI：0.99，1.02)或按诊断时间计算，或前列腺癌亚型，包括肿瘤分期和组织学分级。
结论：估计的循环游离IGF-I与前列腺癌风险无关。进一步的研究可以考虑评估生物可利用的IGF-I的其他测定方法，以提供对循环总IGF-I与随后的前列腺癌风险之间充分证实的关联的更多见解。
方法：我们分析了来自767例前列腺癌病例和767例配对对照的欧洲癌症和营养队列前瞻性调查的数据。平均14年（四分位距=2.9）随访。匹配变量是研究中心，随访时间，年龄,以及一天中的时间和采血时的禁食持续时间。使用酶联免疫吸附测定（ELISA）测量招募时收集的血清样品中的循环游离IGF-I浓度（平均年龄55岁；标准偏差=7.1）。进行条件逻辑回归以检查游离IGF-I与前列腺癌总体风险的关联，并按诊断时间（≤14和>14年）细分。和肿瘤特征。
结果：循环游离IGF-I浓度（占四分之一，作为连续变量）与前列腺癌总体风险无关（比值比[OR]=1.00每0.1nmol/L增量，95%CI：0.99，1.02)或按诊断时间计算，或前列腺癌亚型，包括肿瘤分期和组织学分级。
结论：估计的循环游离IGF-I与前列腺癌风险无关。进一步的研究可以考虑评估生物可利用的IGF-I的其他测定方法，以提供对循环总IGF-I与随后的前列腺癌风险之间充分证实的关联的更多见解。
