Prostate size correlates with fasting blood glucose in non-diabetic benign prostatic hyperplasia patients with normal testosterone levels

Antidiabetic drugs, glycemic control and risk of benign prostatic hyperplasia

BACKGROUND

Diabetes has been associated with an increased risk of benign prostatic hyperplasia (BPH). However, the role of antidiabetic drugs as a BPH risk factor is unclear. The objective of our study was to examine the risk of BPH by antidiabetic drug use and glycemic control in a large population-based cohort of Finnish men.

METHODS

A total of 74,754 men in the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC) free of BPH at baseline in 1996-1999 were linked to the national medication reimbursement database for information on physician-prescribed antidiabetic drug purchases. Information on recorded BPH procedures and diagnoses was obtained from the National Care Register for Health Care, and for a subgroup of 17,739 men, information on blood glucose levels (BGLs) from the Fimlab Laboratories database. Cox regression with antidiabetic drug use and BGL as time-dependent variables was used to analyze the risks for starting BPH medication, recorded BPH diagnosis, and undergoing BPH surgery. The analysis was adjusted for age, use of statins, antihypertensive medication, and nonsteroidal anti-inflammatory drugs.

RESULTS

Of the subjects, 14,012 men (18.7%) used antidiabetic medication. Of the subgroup with fasting blood glucose data available, 7487 (42.2%) had diabetic level. The risks for BPH diagnosis (HR: 1.08, 95% CI: 1.03-1.13) and surgery (HR: 1.16, 95% CI: 1.09-1.24) were slightly elevated among antidiabetic drug users compared to nonusers. The association was strongest for insulin use. Similarly, risk of BPH surgery was increased in men with diabetic blood glucose compared to normoglycemic men. The risk association was attenuated by use of antidiabetic drugs.

CONCLUSIONS

Diabetic BGL and antidiabetic medication use, especially insulin, are associated with an elevated risk of BPH surgery compared to nondiabetic men. These findings support the roles of insulin use and untreated hyperglycemia as possible BPH risk factors.

The association of new-onset diabetes mellitus and medical therapy for benign prostatic hyperplasia: A population-based study

INTRODUCTION

Benign prostatic hyperplasia (BPH) and associated lower urinary tract symptoms are highly prevalent in the aging male. Similarly, the prevalence of metabolic syndrome is increasing worldwide, with mounting evidence that these two common conditions share more than age as a predisposing factor. The objective of this study was to determine if medical management of BPH is associated with an increased risk of new-onset diabetes mellitus (DM) in routine care.

METHODS

This population-based, retrospective cohort study expands on a parent study of linked administrative databases identifying patients diagnosed and treated for BPH between 2005 and 2015. The primary outcome of this secondary analysis was a new diagnosis of DM after the index date of BPH diagnosis. Covariates included age, dyslipidemia, hypertension, and vascular diseases. A Cox proportional hazards regression model was used for inferential statistical analysis.

RESULTS

A total 129 223 men were identified with a BPH diagnosis and no prior history of DM. Of those men, 6390 (5%) were exposed to 5-alpha-reductase inhibitor (5-ARI), 39 592 (31%) exposed to alpha-blocker (AB), and 30 545 (24%) exposed to combination therapy. Compared to those men with no BPH medication use, those exposed to drugs had an increased risk of new DM. Men treated with combination therapy of 5-ARI and AB (hazard ratio [HR] 1.30, 95% confidence interval [CI] 1.25-1.35), 5-ARI monotherapy (HR 1.25, 95% CI 1.17-1.34), or AB monotherapy (HR 1.17, 95% CI 1.13-1.22) all were at higher risk of new DM diagnosis after adjusting for important covariates. When calculating the risk of a new diabetes diagnosis measured from the start of drug exposure, men treated with 5-ARIs had an increased risk of DM compared to AB monotherapy as the reference, with HR 1.12 (95% CI 1.03-1.21) for 5-ARI monotherapy and HR 1.20 (95% CI 1.14-1.25) for combination therapy.

CONCLUSIONS

In this large, long-term, retrospective study of men with a BPH diagnosis in routine practice, the risk of a new diagnosis of DM was greater in patients receiving medical management compared to controls. This modest but significant increased risk was highest in men treated with any 5-ARIs, in combination as well as monotherapy, compared to the ABs.

Association between pyrethroids and prostate endpoints; stratified according to renal function

BACKGROUND

Pyrethroids, one of the most commonly used pesticide classes, are considered to be selectively toxic toward insects rather than toward humans. However, there are accumulating data about pyrethroids toxicity in humans, especially sex organs. Thus, we investigated whether pyrethroids affected reproductive organs, especially the prostate gland.

METHODS

With 1305 subjects who participated in the National Health and Nutrition Examination Survey, several measurements were performed: 3-phenoxybenzoic acid (3-PBA), a common metabolite of pyrethroids; prostate-specific antigen (PSA); and other covariates. Both logistic and linear regression analyses were performed after stratifying according to kidney function, which was evaluated based on the estimated glomerular filtration rate (eGFR).

RESULTS

By logistic regression, the ORs (95% CIs) of the highest quantile to the reference group for higher total PSA were 2.039 (1.018 - 4.084) in the total study population and 2.219 (1.083-4.548) in the high eGFR group. The ORs (95% CIs) of the highest quantile to the reference group for a lower PSA ratio were 1.979 (1.057 - 3.707) in the total study population and 2.101 (1.086 - 4.064) in the high eGFR group. By linear regression, a marginally significant positive correlation between urinary 3-PBA and total PSA (β ± Standard Error = 0.049 ± 0.026, p = 0.0712) and a significant positive correlation between urinary 3-PBA and PSA ratio (β ± Standard Error = 0.018 ± 0.007, p = 0.0191) among the low eGFR group were observed.

CONCLUSION

This study showed that exposure to pyrethroids was associated with either increased levels of total PSA or alterations in the PSA ratio.

Association of type 2 diabetes mellitus and antidiabetic medication with risk of prostate cancer: a population-based case-control study

BACKGROUND

Prostate cancer (PCa) and type 2 diabetes mellitus (T2DM) are prevalent conditions that often occur concomitantly. However, many aspects of the impact of T2DM, particularly the duration of T2DM and antidiabetic medications, on PCa risk are poorly understood.

METHODS

To assess the association of duration of T2DM and antidiabetic medication with PCa risk, we designed a matched case-control study, including 31,415 men with PCa and 154,812 PCa-free men in Prostate Cancer data Base Sweden (PCBaSe) 4.1.

RESULTS

Overall, a decreased risk of PCa was observed for men with T2DM (odds ratio (OR): 0.81, 95% confidence interval (CI): 0.78-0.84), as compared to men without T2DM. The decreased risk of PCa was consistently showed across duration of T2DM. With respect to use of antidiabetic drugs, this inverse association with duration was also found for all medications types, as compared to men without T2DM, including insulin, metformin and sulphonylurea (SU) (e.g. 3- < 5 yr insulin OR:0.69, 95%CI:0.60-0.80; 3- < 5 yr metformin OR: 0.82, 95%CI: 0.74-0.91; 3- < 5 yr SU OR: 0.72, 95%CI: 0.62-0.83). When stratifying by PCa risk categories, this decreased risk was most evident for diagnosis of low and intermediate-risk PCa (low-risk OR: 0.65, 95%CI: 0.66-0.70, intermediate-risk OR: 0.80, 95%CI: 0.75-0.85).

CONCLUSIONS

The study showed an inverse association between pre-existing T2DM and PCa across different durations of T2DM and all types of T2DM medication received. This inverse association was most evident for low- and intermediate-risk PCa, suggesting that whilst T2DM and its medication may protect some men from developing PCa, the relationship warrants further study.

Serum omentin-1 level in patients with benign prostatic hyperplasia

Backgroud

To evaluate the relationship between omentin-1 and benign prostatic hyperplasia (BPH). BPH is the most common urological disease in elderly men worldwide. Lower serum omentin-1 levels were reported to be negatively associated with the incidence of inflammation, diabetes, obesity and metabolic syndrome, which all play a role in the development of BPH. To the best of our knowledge, the relationship between omentin-1 and BPH has not been investigated previously.

Methods

A total of 70 males participated in this study, including forty patients diagnosed with BPH and thirty healthy males. The anthropometric measurements and the biochemical parameters were measured in this study. We evaluated serum omentin-1 levels and the correlation with those data. We also test the gene expression of IL-8, IL-18 in BPH group using the TURP tissues.

Results

The serum omentin-1 levels were lower in the BPH patients than in the control group (27.95 ± 4.18 versus 32.03 ± 5.46, p < 0.001). The general characteristics and biochemical parameters were investigated, and a negative correlation was found between serum omentin-1 levels and BMI in the BPH group (r = − 0.391, p = 0.013) as well as the whole group (r = − 0.457, p < 0.001). Multiple-factor binary regression analysis revealed that serum omentin-1was a protective factor of BPH development. Furthermore, lower serum omentin-1 levels were associated with higher mRNA expression of IL-8 or IL-18 in the BPH group.

Conclusion

Omentin-1 may suppress the development of BPH and Lower serum omentin-1 levels in BPH patients might associated with higher prostate volume and higher IL-8 and IL-18 expression levels in their prostatic cells.

Comparison of prostate size and anthropometric parameters between diabetic and non-diabetic Congolese patients who underwent transurethral prostate resection in the Democratic Republic of Congo

Background

Benign prostate hyperplasia (BPH) and type 2 diabetes mellitus are prevalent in older men, and both represent a challenge to public health. Prior studies reported a correlation between BPH and (hyper)glycaemia, a component of the metabolic syndrome, which is on the increase in sub-Saharan Africa (SSA) due to rapid modernization. This study was designed to evaluate the association of prostate volume and anthropometric parameters among diabetic and non-diabetic patients who had transurethral resection of the prostate (TURP) for BPH.

Results

We analyzed data of 159 selected patients who had TURP over a three-year period (February 2014–January 2017) for histologically confirmed BPH. Mean age in the entire cohort was 68 ± 8.5 years. Out of the 159 patients, 94 (59.1%) were non-diabetics and 65 (40.9%) were diabetics. International Prostate Symptom Score (IPSS) and fasting blood glucose were significantly higher in diabetic than in non-diabetic group (28.6 ± 4.3 vs 25.6 ± 6.4, and p 0.005; 121.7 ± 45.7 vs 85.4 ± 11.7 mg/dl, and p < 0.001, respectively). BMI and waist circumference were statistically greater in non-diabetics than in diabetics (25.1 ± 3.3 kg/m2 vs 23.6 ± 3.5 kg/m2, and p 0.008; 94.6 cm ± 10.3 vs 90.6 ± 10.4 cm, and p 0.018). Diabetic patients had larger prostate volume than non-diabetic in the working age subgroup only (< 65 years of age); beyond 65 years, this difference was not consistent (62.6 ± 23.1 cc vs 50.1 ± 20.7 cc, and p 0.027; 56.2 ± 23.7 cc vs 49 ± 20.2 cc, and p 0.15, respectively). Prostate size was significantly associated with fasting blood glucose (p = 0.002) and PSA (p = 0.027). However, prostate size was not related to age, presence of diabetes, BMI, waist circumference, IPSS, quality of life score, and duration of symptoms.

Conclusion

Prostate volume is not correlated with anthropometric parameters in diabetic and non-diabetic Congolese patients who had TURP in South Kivu. Diabetics were not obese and yet had larger prostate volume than non-diabetics < 65 years of age. It is hoped that these results would form groundwork for further studies on this topic in SSA region.

Comparison of Clinical and Physiological Parameters for Benign Prostatic Hyperplasia in Hypertensive and Normotensive Patients

Objective: To discover the correlation of clinical and physiological measures for benign prostatic hyperplasia in hypertensive and normotensive patients.

Methods: From September 2016 to October 2017, 435 patients were enrolled for further selection. The parameters evaluated for eligible patients included prostate volume, systolic blood pressure, diastolic blood pressure, international prostate symptom score, etc. Then the eligible patients were divided into two groups according to hypertension condition, and the clinical and physiological parameters were compared between two groups. The Pearson’s correlation coefficient was used to test the linearity of the relationships of these clinical and physiological components with prostate volume, total prostate specific antigen, and international prostate symptom score.

Results: Finally, 350 patients were involved in this study, including 117 with hypertension and 233 without hypertension. Weight, body mass index, systolic blood pressure, and diastolic blood pressure were significantly different between the hypertension and normotension groups. In the normotension group, there were positive correlations between weight, body mass index, age, and prostate volume; between fasting blood sugar, systolic blood pressure, diastolic blood pressure, and total prostate specific antigen; between fasting blood sugar and international prostate symptom score. In the hypertension group, there were positive correlations between age and total prostate specific antigen and international prostate symptom score; between weight and prostate volume; between systolic blood pressure and total prostate specific antigen.

Conclusion: This study indicated that there might be no significant association between hypertension and prostate volume.

Comparison between selected hormone and protein levels in serum and prostate tissue homogenates in men with benign prostatic hyperplasia and metabolic disorders

Purpose

The purpose of the study was to assess the relationship between changes in the levels of selected hormones in serum and prostate tissue homogenate in regard to metabolic disorders in patients with diagnosed, surgically treated benign prostatic hyperplasia (BPH).

Patients and methods

The study involved a group of 154 men with a diagnosis of BPH with metabolic syndrome (MetS) and without MetS. The serum levels of the hormones – total testosterone, free testosterone, insulin, dehydroepiandrosterone sulfate, estradiol, luteinizing hormone, sex hormone binding globulin (SHBG), and insulin-like growth factor-1 (IGF-1) – were determined using the ELISA method. Prostate tissue sections obtained from the patients during transurethral resection of the prostate were frozen in liquid nitrogen. We determined the levels of the same hormones.

Results

There was a statistically significant difference between the groups in terms of serum SHBG levels, but not in the prostate tissue SHBG levels. A similar relationship was observed in regard to IGF-1, the serum levels of which were significantly higher in patients with MetS. MetS had an effect on the ratio of hormone levels in serum to their levels in the prostate tissue. Correlations between the levels of biochemical parameters and the levels of hormones in serum and the prostate tissue of BPH patients with and without MetS demonstrate that serum SHBG levels correlated weakly with waist size and triglyceride levels.

Conclusion

The occurrence of MetS in BPH patients was associated with changes in the levels of hormones and proteins. These changes, however, were not always equivalent to changes in the levels of these parameters in prostate tissue. It should also be mentioned that MetS in BPH patients had an influence on a quantitative balance between the levels of SHBG in serum and prostate tissue.

Comparative analysis of resected prostate weight in diabetic and non-diabetic benign prostatic hyperplasia Patients

Background:

Benign prostatic hyperplasia (BPH) is the most common benign tumor in men. The etiology of BPH is still unresolved and multiple systems are likely to be involved. The effects of diabetes on urinary system are a risk factor for BPH. We then assessed the effects of diabetes on the parameters related to BPH, especially weight and volume.

Methods:

This study was conducted on patients with BPH who underwent surgery during 2010-2013. The patients’ demographic and clinical data including age, height, weight, history of diabetes, abdominal sonography, prostate-specific antigen(PSA), fasting blood sugar (FBS), triglyceride, and cholesterol, resected sample weight, and pathological diagnosis were extracted.

Results:

The mean age of all 225 patients (35 (15.6%) diabetic patients and 190 (84.4%) non-diabetic patients) who entered the study was 71.5±8.7 years. The patients were divided in to 3 body mass index (BMI) groups: 48 (21.3%) were normal, 151 (67.1%) were overweight and 26 (11.6%) were obese. The mean weight of resected prostate was higher in diabetic patients (22.9±6.9 vs 21.7±14.3, P=0.02). The resected prostate weight had a significant relationship with BMI (P=0.001), prostate–specific antigen (PSA) level (P=0.001), and prostate volume sonography (P=0.001). No significant relationship was detected between resected prostate weight with age, FBS and triglyceride however, it is significant with cholesterol.

Conclusion:

We concluded that diabetes has a role in the development and progression of BPH with effect on prostate weight and volume. As well, BMI is a risk factor in BPH progression.

Oxytocin: its role in benign prostatic hyperplasia via the ERK pathway

The aim of the present study was to evaluate oxytocin and benign prostatic hyperplasia (BPH), and study the cell signalling mechanism. Investigation was performed in patients about the correlation between oxytocin level and BPH. Mice were injected with oxytocin or oxytocin antagonist for 2 weeks and the prostate morphology was studied after their sacrifice. Furthermore, in vitro experiments were performed to evaluate the oxytocin effect through the MEK/ERK/RSK pathway. Oxytocin was significantly elevated in the serum and prostate tissue of patients with BPH, and a positive correlation with prostate volume indicated. In the animal experiments, prostate enlargement was observed in the oxytocin-treated group, whereas oxytocin antagonist reduced prostate hyperplasia. The in vitro study confirmed this result and also revealed activation of the MEK/ERK/RSK pathway. Oxytocin is highly expressed in the serum and prostate tissue of patients with BPH. In addition, oxytocin aggravates BPH and the oxytocin-induced proliferative effect on prostatic cells is mediated through the MEK/ERK/RSK pathway, at least partly. Thus, the hypothalamic regulation may be involved in development of BPH, which may open a new door to more medications for BPH in the future.

5-alpha-reductase inhibitors and the risk of diabetes mellitus: A nationwide population-based study

BACKGROUND

This nationwide population-based study investigated the risk of type 2 diabetes mellitus (DM) after 5-alpha-reductase inhibitor (5ARI) therapy for benign prostate hyperplasia (BPH) using the National Health Insurance Research Database (NHIRD) in Taiwan.

METHODS

In total, 1,298 adult patients newly diagnosed with BPH and who used more than 28 cumulative defined daily doses (cDDD) of 5ARI were recruited as the therapy group cohort, along with 1,2887 subjects who did not use more than 28 cDDD of 5ARI as a control group from 2002 to 2009. Each patient was monitored for 5 years (from 2003 to 2008) to identify those who subsequently developed type 2 DM. A Cox proportional hazards model was used to compare the risk of type 2 DM between the study and comparison cohorts after adjusting for possible confounding risk factors.

RESULTS

Patients who received 5ARI therapy had a lower cumulative rate of type 2 DM than those who did not receive 5ARI during the five-year follow-up period (3.5% vs. 5.3%, P = 0.003). In sub-group analysis, among the BPH patients aged <65 years, the five-year type 2 DM events hazard ratio (HR) of 5ARI users was lower than that of nonusers (HR: 0.47, 95% confidence interval (CI): 0.24-0.91; P = 0.026).

CONCLUSIONS

Therapy with 5ARI may decrease the five-year risk of type 2 DM in the BPH patients younger than 65 years. Further mechanistic research is warranted to validate the results.

Benign prostatic hyperplasia complicated with T1DM can be alleviated by treadmill exercise-evidences revealed by the rat model

Background

Both benign prostatic hyperplasia (BPH) and Type-1 diabetes mellitus (T1DM) share similar epidemiologic features and are all associated with the insulin-like growth factor (IGF)-mediated hormonal imbalance. The purpose of this study is to understand whether exercise (EX) could alleviate DM and DM + BPH.

Methods

Sprague-Dawley rats were divided into eight groups: normal control, EX, BPH, BPH + EX, DM, DM + EX, BPH + DM, and BPH + DM + EX. T1DM was induced by intraperitoneal (ip) injection of streptozotocin (65 mg/kg) in Week 2, and BPH was induced by successive ip injections of Sustanon® (testosterone, 3.5 mg/head) plus estradiol (0.1 mg/head) from Week 3 to Week 9. Treadmill exercise training (20 m/min, 60 min per time) was performed three times per week for 6 weeks.

Results

In BPH + EX, EX maintained at a constant body weight (BW); and suppressed stromal layer thickening, collagen deposition, blood glucose (BG), levels of testosterone (Ts), 5α-reductase(5αRd), dihydrotestosterone (DHT), androgen receptor (AR), serum hydrogen peroxide, TBARs, and interleukin-6 (IL-6). EX recovered testes size and substantially increased nitric oxide (NO) levels. In DM + EX group, EX decreased BW, PW, nuclear proliferation, inflammatory cell aggregation, collagen deposition, and BG. As contrast, EX upregulated insulin, IGF, Ts, NO, 5αRd, AR, and DHT, and substantially reduced PSA. In BPH + DM + EX, EX maintained BW at a subnormal level, slightly suppressed prostate stromal inflammation, collagen deposition, and BG, moderately restored sIn and IGF. Although failed to suppress Ts, EX highly upregulated 5αRd and suppressed DHT and AR, together with highly upregulated NO resulting in substantially reduced PSA.

Conclusion

EX, by remodeling androgen and NO expressions, can effectively alleviate BPH, DM, and BPH + DM.

Effect of obesity and hyperglycemia on benign prostatic hyperplasia in elderly patients with newly diagnosed type 2 diabetes

PURPOSE

To investigate the relationship between blood glucose levels, age, body mass index (BMI), and benign prostatic hyperplasia (BPH) in patients with newly diagnosed type 2 diabetes.

METHODS

A total of 141 BPH patients with newly diagnosed type 2 diabetes participated in this study. Their glucose level, international prostate symptom score (IPSS), prostate volume (PV), and maximum urinary flow rate (Qmax) were determined and analyzed.

RESULTS

Compared to patients in 60-69 years of age, those in 70-79 years of age had higher IPSS and PV values (11.10±2.68 vs. 16.09±2.64, respectively; P<0.01; 38.67±4.65 vs. 44.76±2.84, respectively; P<0.01) as did patients ≥80 y (11.10±2.68 vs. 19.87±3.35, respectively; P<0.01; 38.67±4.65 vs. 51.38±3.74, respectively; P<0.01). The Qmax was lower in the ≥80 y group compared to the 60-69 y group (7.91±2.13 vs. 13.50±1.75, respectively; P<0.01). IPSS, PV, and insulin resistance index (HOMA-IR) were higher in patients with a BMI ≥28 kg/m(2) group as compared to those with a BMI <24 kg/m(2) group. IPSS and PV values were higher in patients with HbA1c levels ≥6.5% than in those with HbA1c<6.5% (16.30±3.31 vs. 9.87±1.07, respectively; P<0.01; 45.69±3.97 vs. 36.64±3.30, respectively; P<0.01), and the Qmax was lower (10.61±1.98 vs. 14.40±0.82, respectively; P<0.01).

CONCLUSIONS

Aging, obesity, high glucose level, and insulin resistance increase the risk of BPH progression in elderly patients with newly diagnosed type 2 diabetes. Managing body weight and lowering the level of glycosylated hemoglobin may slow the progression of BPH in people with type 2 diabetes.

Impact of metabolic syndrome on response to medical treatment of benign prostatic hyperplasia

Purpose

To investigate the effect of metabolic syndrome (MetS) on the response to medical therapy of benign prostatic hyperplasia (BPH) after a 3-month period of treatment.

Materials and Methods

This was a cohort study of 100 patients, 47 with MetS and 53 without MetS, referred to either the primary care unit or referral hospital with BPH who had moderate lower urinary tract symptoms of prostate involvement and were candidates for medical treatment. Our main outcome was response to medical treatment with prazosin 1 mg twice a day and finasteride 5 mg daily in patients with BPH on the basis of International Prostate Symptom Score (IPSS). Multivariate analysis of covariance was used to compare BPH treatment response in patients with and without MetS before and after receiving treatment.

Results

The mean volume of the prostate was significantly higher in MetS patients than in patients without MetS (57±32.65 mL compared with 46.00±20.19 mL, p=0.036). The control group demonstrated an 11-unit reduction in IPSS, whereas those with MetS showed a reduction in the symptom score of only 6 units (p<0.001). Regarding the components of MetS separately, triglyceride (p<0.001), fasting blood sugar (p=0.001), and waist circumference (p=0.028) significantly affected the clinical progression of BPH. The observational nature of this study may be a limitation in comparison with an interventional study.

Conclusions

The results of the present study showed that MetS can negatively affect the response to medical treatment of BPH. Therefore, it is necessary to consider MetS in selecting patients with BPH for drug therapy.

Why are diabetics at reduced risk for prostate cancer? A review of the epidemiologic evidence

A large body of epidemiologic evidence provides strong support for the notion that type-2 diabetics are at decreased risk for prostate cancer. In this review article, we summarize the epidemiologic literature that explores the role of diabetes mellitus and related biomarkers in prostate cancer risk and detection, in order to create a better understanding of the potential mechanisms that underlie this inverse association. The bulk of the data supporting this association comes from the USA, as evidence for this association is less consistent in many other regions of the world. The relationship between diabetes and prostate cancer is suspected to be causal due to evidence of decreasing prostate cancer risk with increasing diabetes duration and lack of evidence for any confounding of this association. Hypothesized mechanisms for decreased prostate cancer risk among diabetics include (1) decreased levels of hormones and other cancer-related growth factors among diabetics, (2) the impact of diabetes on detection-related factors, such as prostate size, circulating prostate-specific antigen (PSA), and health-care seeking behaviors, (3) protective effects of diabetes medications, and (4) a protective effect of diabetes-induced vascular damage in the prostate. The evidence for screening-related factors is compelling, as diabetics appear to have reduced PSA and lower levels of health-care seeking behavior compared with nondiabetics. Furthermore, the inverse association between diabetes and prostate cancer is much less apparent in populations that do not perform biopsies based on PSA levels and in studies restricted to biopsied individuals. The inverse association appears to be stronger for low-grade disease, as compared with high-grade (Gleason >7), which is consistent with the observation that among patients receiving biopsy or prostate cancer treatment, diabetics are more likely to have high-grade disease as compared to nondiabetics, potentially resulting in worse outcomes for diabetics. Epidemiological research has reveals a great deal regarding the relationship between diabetes and prostate cancer risk, but additional research is needed to further clarify the mechanisms underlying this inverse association.

Elevated insulin and insulin resistance are associated with the advanced pathological stage of prostate cancer in Korean population

The study was designed to investigate the effect of serum glucose, insulin and insulin resistance on the risk of prostate cancer (CaP) and on the clinicopathological characteristics in Korean men. Subjects were retrospectively recruited from 166 CaP patients underwent radical prostatectomy and 166 age-matched benign prostatic hyperplasia (BPH) patients. The serum was taken on the morning of the day of operation and insulin resistance was assessed by homeostasis model assessment insulin resistance index (HOMA-IR). Men in highest tertile of insulin was associated with 55% reduced odds of CaP than those with the lowest tertile (OR = 0.45, 95% CI = 0.23-0.89, P = 0.022). The patients in highest tertile of insulin had a more than 5.6 fold risk of locally advanced stage than those in the lowest tertile (OR = 5.62, 95% CI = 1.88-16.83, P = 0.002). Moreover, the patients in the highest tertile HOMA-IR group was associated with an increased risk of locally advanced stage than the lowest tertile group (OR = 3.10, 95% CI = 1.07-8.99, P = 0.037). These results suggest that elevated insulin and insulin resistance are associated with the advanced pathological stage of prostate cancer in Korean patients.