Honda G D, Bernstein L, Ross R K, Greenland S, Gerkins V, Henderson B E
Tulane University, School of Medicine, New Orleans, Louisiana.
Br J Cancer. 1988 Mar;57(3):326-31. doi: 10.1038/bjc.1988.74.
A population-based case-control study was conducted in men aged 60 or less to assess the risk of prostate cancer associated with vasectomy and other factors. Data were obtained from 216 case-control pairs by telephone interviews; this number represented 55% of all eligible cases. The matched pairs relative risk (RR) for vasectomy in ever married men was 1.4 with a 95% confidence interval (CI) of 0.9-2.3. There was a positive association between the number of years since vasectomy and prostate cancer risk (1-sided P = 0.01). Early age at first sexual intercourse was associated with increased prostate cancer risk (age less than 17 vs. 21+, RR = 2.3, 95% CI = 1.3, 4.0) but there were no consistent associations with number of sexual partners or frequency of sexual intercourse. Cigarette smoking was also associated with increased risk of prostate cancer (RR = 1.9, 95% CI = 1.2, 3.0) and there was a positive dose-response relationship with years of smoking (1-sided P = 0.001). We discuss the possible implication of the low response rate on each of these findings. To determine whether the association with vasectomy might have a hormonal basis, we compared levels of testosterone (T) and testosterone binding globulin-binding capacity (TeBG-bc) in 33 of the vasectomized control men with levels in 33 non-vasectomized controls of the same age, weight and height. T levels were higher in vasectomized than in non-vasectomized controls (1-sided P = 0.06). The ratio of T to TeBG-bc (an index of bioavailable T) was 13.5% higher in vasectomized men (1-sided P = 0.03).
开展了一项基于人群的病例对照研究，以评估60岁及以下男性输精管切除术及其他因素与前列腺癌风险的相关性。通过电话访谈从216对病例对照中获取数据；这一数字占所有符合条件病例的55%。已婚男性输精管切除术的配对相对风险（RR）为1.4，95%置信区间（CI）为0.9 - 2.3。输精管切除术后的年限与前列腺癌风险之间存在正相关（单侧P = 0.01）。首次性交年龄较小与前列腺癌风险增加相关（17岁以下与21岁及以上相比，RR = 2.3，95% CI = 1.3，4.0），但与性伴侣数量或性交频率没有一致的相关性。吸烟也与前列腺癌风险增加相关（RR = 1.9，95% CI = 1.2，3.0），并且与吸烟年限存在正剂量反应关系（单侧P = 0.001）。我们讨论了低应答率对这些发现中每一项的可能影响。为了确定与输精管切除术的关联是否可能有激素基础，我们比较了33名输精管切除的对照男性与33名年龄、体重和身高相同的未进行输精管切除的对照男性的睾酮（T）水平和睾酮结合球蛋白结合能力（TeBG - bc）。输精管切除的男性T水平高于未进行输精管切除的对照男性（单侧P = 0.06）。输精管切除的男性中T与TeBG - bc的比值（生物可利用T的指标）高13.5%（单侧P = 0.03）。
