1型糖尿病患者的PSA检测值不可靠

亚特兰大(EGMN)—— 华盛顿大学的James Hotaling博士在美国泌尿学会(AUA)年会上报告，1型糖尿病患者即使患有早期前列腺癌，可能也不会表现出前列腺特异性抗原(PSA)水平升高。这项前瞻性研究显示，血糖控制不佳与PSA水平下降相关，不论年龄或块头。

 “众所周知，2型糖尿病患者的前列腺癌风险和PSA水平均较低。人们认为，PSA水平之所以较低是由于2型糖尿病患者常常超重或肥胖，使得PSA分布于更大体积内。还有人猜测，这一现象也与肥胖患者的睾酮水平较低有关。”

为了确定1型糖尿病患者是否也存在这一现象，Hotaling博士及其同事分析了来自糖尿病干预与并发症的流行病学(EDIC)研究的数据。EDIC研究始于1994年，是糖尿病控制与并发症试验(DCCT)的后续研究，对1441例受试者进行了17年观察性随访。

研究者在随访第17年时检测了627名男性的PSA浓度，此时其平均年龄为52岁。根据年龄(＜40岁、41~59岁和≥60岁)和体重指数(正常、超重和肥胖)将受试者分层。结果显示，受试者的平均HbA1c水平为8%，平均PSA水平为0.93 ng/ml。

PSA水平随着年龄而增加，从最年轻患者的平均0.56 ng/ml增至最年长者的平均1.38 ng/ml。PSA水平随着HbA1c增加而显著下降，HbA1c低于7.5%者的PSA平均水平为1.05 ng/ml，而HbA1c高于8.5%者为0.76 ng/ml。“”

上述研究结果提示，与糖尿病相关的代谢差异可能影响早期前列腺癌的检测，或许也是一种可干预的潜在危险因素。

研究者称，低PSA与高血糖之间的生理关联尚不明确，“一种可能的机制是，高胰岛素血症和胰岛素抵抗导致雌二醇增多，后者引起睾酮和性激素结合球蛋白减少，从而导致PSA浓度下降”。

EDIC由美国国立糖尿病、消化与肾脏疾病研究所发起。Hotaling博士报告无相关利益冲突。

爱思唯尔  版权所有

ALANTA (EGMN) – Men with type 1 diabetes might not express an elevated level of prostate specific antigen, even if they have an early prostate cancer, suggest findings from a subanalysis of patients with type 1 diabetes.

In that prospective study, poor glycemic control was associated with decreased PSA levels, irrespective of age or body size, Dr. James Hotaling said during a poster session at the annual meeting of the American Urological Association.

“It’s well known that patients with type 2 diabetes have a decreased risk of prostate cancers as well as lower PSAs,” said Dr. Hotaling of the University of Washington, Seattle.

“This lower PSA is thought to stem from a greater volume of distribution because many of these men are overweight or morbidly obese – and some hypothesize that they have lower testosterone because of the obesity and that this contributes to these findings.”

Dr. Hotaling and his colleagues sought to determine whether men with type 1 diabetes showed a similar pattern. To do this, they examined data from year 17 of the Epidemiology of Diabetes Interventions and Complications (EDIC) study. EDIC began in 1994 and is the observational follow-up study of 1,441 participants in the earlier Diabetes Control and Complications Trial (DCCT).

PSA concentrations were measured in 627 men during year 17. The investigators stratified the subjects by both age (younger than 40 years, 41-59 years, and 60 years and older) and body mass index (normal, overweight, obese).

The subjects were a mean age of 52 years at the time of PSA measurement. Their mean HbA1c was 8%, and the mean PSA 0.93 ng/mL.

PSA levels increased with age, from a low of 0.56 ng/mL in the youngest patients to a mean of 1.38 ng/mL in the oldest group.

PSA levels significantly decreased as HbA1c increased. The mean PSA was 1.05 ng/mL when blood sugar was less than 7.5% and 0.76 ng/mL when blood sugar was above 8.5%.

“Each 10% increase in HbA1c levels was associated with a PSA reduction of 1.37ng/mL,” Dr. Hotaling said. “This association was independent of age and body size.”

Our findings suggest that metabolic differences related to diabetes may affect the ability to detect early-stage prostate cancer. This finding also could represent a potentially modifiable risk factor that could be addressed.

The physiologic relationship between hyperglycemia and low PSA is not completely known, he added. “Proposed mechanisms are that hyperinsulinemia and insulin resistance lead to increased estradiol, which causes decreased testosterone and sex hormone–binding globulin, thus leading to a decreased PSA concentration.”

EDIC is sponsored by the U.S. National Institute of Diabetes and Digestive and Kidney Diseases. Dr. Hotaling reported having no financial disclosures.