The effects of type 2 diabetes and hypertension on changes in serum prostate specific antigen levels: results from the Olmsted County study

Association between body mass index and hemoglobin A1c with serum prostate-specific antigen level: A retrospective cohort study

OBJECTIVES

To assess the association between body mass index (BMI) and hemoglobin A1c (HbA1c) with serum prostate-specific antigen (PSA) level.

METHODS

A retrospective cohort study was carried out at King Faisal Specialist Hospital and Research Centre in Riyadh, Saudi Arabia, from January 2016 to December 2021. Data were collected from the medical records of patients who visited the family medicine clinics, including demographics, smoking status, BMI value, index PSA level, testosterone level, digital rectal exam findings, prostate biopsy status, fasting blood glucose (FBG), HbA1c, diabetes duration, chronic comorbidities (namely, hypertension, dyslipidemia, or chronic kidney disease), and medication history.

RESULTS

The mean PSA level was 1.89±4.02 ng/dL and mean HbA1c was 6.59±2.69%. Of the participants, 41.8% were overweight, 54.3% were non-diabetics, and 85.3% were nonsmokers. Only 11 (1.6%) participants had undergone a prostate biopsy after taking a PSA test. There was a positive correlation between PSA level and age, a negative correlation between PSA level and BMI, and no correlation between PSA level and HbA1c or FBG.

CONCLUSION

Prostate-specific antigen levels were higher in older people and those with low BMIs. No correlations were found between PSA levels and HbA1c or FBG, even after adjusting for other variables. Moreover, no correlations were found between PSA levels and other comorbidities such as dyslipidemia, chronic kidney disease, and hypertension.

Outcomes of prostate cancer screening among men using antidiabetic medication

Diabetic men have decreased risk for prostate cancer (PCa) overall and lower PSA compared to non-diabetics. This may affect the outcomes of PSA-based screening. We investigated the effect of PSA-based screening at 4-year intervals on PCa incidence and mortality separately among users and non-users of antidiabetic medication with the hypothesis that screening would detect less low-grade cancer and more high-grade cancer in diabetic men. A cohort of 80,458 men from the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC) were linked to national prescription database to obtain information on antidiabetic medication purchases. PCa risk and mortality were compared between the FinRSPC screening arm (SA) and the control arm (CA) separately among users and non-users of antidiabetic medication. Among antidiabetic medication users median PSA was lower than in non-users (0.93 and 1.09 ng/ml, respectively, P for difference = 0.001). Screening increased overall PCa incidence compared to CA after the first screen both among medication users and non-users (HR 1.31, 95% CI 1.08–1.60 and HR 1.55, 95% CI 1.44–1.66, respectively). On the second and third screen the difference between SA and CA attenuated only among medication users. Detection of Gleason 6 tumors was lower among medication users, whereas no difference was observed in detection of Gleason 8–10 cancers. Concordantly, screening affected PCa mortality similarly regardless of antidiabetic medication use (HR 0.38, 95% CI 0.14–1.07 and HR 0.19, 95% CI 0.11–0.33 among users and non-users after three screens, respectively. P for difference = 0.18). Median PSA is lower in men using antidiabetic drugs than among non-users. Systematic PSA screening detects less low-risk tumors among medication users, whereas detection of high-risk tumors and mortality effects are similar regardless of medication use. This suggests that antidiabetic medication users may form a suitable target group for PCa screening, with less screening-related overdiagnosis of indolent tumors.

Untangling the association between prostate-specific antigen and diabetes: a systematic review and meta-analysis

Objectives

Several studies have shown an inverse association between diabetes mellitus and prostate cancer (PCa). Some researchers suggest that this relationship is due to reduced PCa detection in diabetics due to lower prostate-specific antigen (PSA) levels compared to non-diabetics. Our objective is to analyze the impact of diabetes on PSA in asymptomatic men without known prostate pathology and without prior prostate intervention.

Methods

We searched Medline (via PubMed), Embase and Scopus. We included studies that reported the relationship between serum PSA levels and diabetes or diabetes treatment in asymptomatic adult men without known prostate pathology, and without prior prostate intervention. Pooled mean differences were compared between diabetics and non-diabetics.

Results

Of 2,392 screened abstracts, thirteen studies met the inclusion criteria and 8 (62%) reported appropriate measures that could be included in a meta-analysis. Eleven (85%) examined the influence of diabetes on PSA levels and 8 (62%) evaluated the influence of diabetes treatments on PSA levels. Overall diabetics had a significantly lower PSA level compared to non-diabetics (mean difference: -0.07 ng/mL; 95% CI -0.10, -0.04).

Conclusions

Diabetes and related factors (such as disease duration, severity and treatment) were significantly associated with lower PSA levels among asymptomatic men, yet differences were small and are unlikely to influence PCa detection in a screening setting.

Association between serum prostate-specific antigen level and diabetes, obesity, hypertension, and the laboratory parameters related to glucose tolerance, hepatic function, and lipid profile: implications for modification of prostate-specific antigen threshold

BACKGROUND

Previous studies indicated inverse relationships between body mass index (BMI), diabetes and prostate-specific antigen (PSA) concentration besides an established positive relationship between age and PSA. Other causal relationships between clinical parameters including hypertension, hepatic function, tests, lipid profile and PSA were also suggested. Thus, we incorporated these parameters all together into the analysis to identify possible determinants of PSA concentration to improve the accuracy of PSA tests.

METHODS

Associations between PSA and the above-mentioned clinical parameters were examined among 14,486 men who visited our hospital for a routine health checkup, using linear regression analyses.

RESULTS

Total of 1403 (9.7%) and 784 (5.4%) men were classified as diabetes and obesity, respectively. After adjusting age, significant PSA reductions were found in diabetic men, especially for men taking antidiabetics. Such association was seen when the diabetic status was represented by hemoglobin A1c (HbA1c) and fasting blood sugar (FBS) levels. That is, PSA levels were significantly reduced in men with higher HbA1c and FBS levels. Obesity was also associated with a reduction in PSA levels. Moreover, PSA levels were significantly decreased with increased ALT levels.

CONCLUSIONS

PSA test results should be carefully interpreted especially for men with diabetes and obesity, in whom a substantial reduction in PSA concentration is likely to occur.

A systematic review of the literature exploring the interplay between prostate cancer and type two diabetes mellitus

Prostate cancer (PCa) and type two diabetes mellitus (T2DM) are both increasing prevalent conditions and often occur concurrently. However, the relationship between the two is more complex than just two prevalent conditions co-existing. This review systematically explores the literature around the interplay between the two conditions. It covers the impact of pre-existing T2DM on PCa incidence, grade and stage, as well as exploring the impact of T2DM on PCa outcomes and mortality and the interaction between T2DM and PCa treatments.

Obesity inversely correlates with prostate-specific antigen levels in a population with normal screening results of prostate cancer in northwestern China

Serum prostate-specific antigen (PSA) is a diagnostic biomarker of prostate cancer and is possibly associated with obesity. This study aimed to explore the relationships between obesity indicators [body mass index (BMI) and waist circumference (WC)] with PSA in Chinese men. A cross-sectional study of men aged 30-85 years undergoing prostate cancer screening was conducted from August 2008 to July 2013 in Xi'an, China. Data were obtained from clinical reports, condition was recorded based on self-report including demographics, weight, height, and WC (>90 cm=obese). Fasting blood glucose (FBG) and prostate volume (PV) were assessed clinically. Patients were grouped by BMI (normal=22.9, overweight=23-27.4, obese≥27.5 kg/m²). PSA parameters of density (PSAD), PSA serum level, and PSA increasing rate per year (PSAR) were calculated per BMI and age groups (30-40, 41-59, 60-85 years). Obesity indicators (BMI and WC) and PSA parameter relationships were modeled by age-stratified linear regression. Of 35,632 Chinese men surveyed, 13,084 were analyzed, including 13.44% obese, 57.44% overweight, and 29.12% normal weight, according to BMI; 25.84% were centrally (abdominally) obese according to WC. BMI and WC were negatively associated with all PSA parameters, except PSAD and PSAR [P<0.05, BMI: β=-0.081 (95%CI=-0.055 to -0.036), WC: β=-0.101 (-0.021 to -0.015)], and independent of FBG and PV (P<0.05) in an age-adjusted model. In conclusion, obesity was associated with lower PSA in Chinese men. Therefore, an individual's BMI and WC should be considered when PSA is used to screen for prostate cancer.

Diabetes, prostate cancer screening and risk of low- and high-grade prostate cancer: an 11 year historical population follow-up study of more than 1 million men

AIMS/HYPOTHESIS

An inverse association has consistently been shown between diabetes and prostate cancer incidence. We investigated whether lower prostate cancer incidence among men with diabetes is attributable to lower detection due to prostate cancer screening patterns.

METHODS

We studied a population-based historical cohort of 1,034,074 Israeli men aged 21-90 years, without a previous history of cancer. The cohort was followed-up from 2002 to 2012, according to diabetes morbidity, for frequency of prostate-specific antigen (PSA) testing, mean PSA values and detection of prostate cancer, after adjustment for age, ethnic origin, socioeconomic status and PSA testing.

RESULTS

In January 2002, 74,756 men had prevalent diabetes. During the 11 year follow-up, 765,483 (74%) remained diabetes-free and 193,835 developed diabetes. Approximately 10% more PSA screening was performed in men with than without diabetes, but the rate of PSA positivity (>4 μg/l) was 20% lower in men with diabetes. PSA values were already significantly lower in men who developed diabetes than in those who did not, 3 years before diabetes diagnosis. Reduced prostate cancer risk was observed among men with incident diabetes only for low-moderate grade tumours (Gleason score 2-6: adjusted HR 0.83; 95% CI 0.77, 0.89). No association was observed for high-grade tumours (Gleason score 7-10: HR 0.99; 95% CI 0.88, 1.11).

CONCLUSIONS/INTERPRETATION

Our findings suggest that diabetes comorbidity is a factor to be considered in prostate cancer screening strategies, and specifically in the interpretation of PSA levels. Furthermore, our demonstration of reduced incidence of low-moderate grade but not high-grade prostate cancer tumours among men with diabetes supports the possibility that low PSA levels, rather than lower tumour risk, explains the observed reduced incidence of prostate cancer in men with diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02072902.

The association between metabolic syndrome and prostate cancer: Effect on its aggressiveness and progression

OBJECTIVES

To evaluate the impact of metabolic syndrome and its individual components on prostate biopsy findings, the radical prostatectomy specimen and on biochemical recurrence.

MATERIAL AND METHODS

An observational study was conducted of 1319 men who underwent prostate biopsy between January 2007 and December 2011. The impact on the biopsy findings, the radical prostatectomy specimen and biochemical recurrence was evaluated using logistic regression and Cox regression.

RESULTS

Of the 1319 patients, 275 (21%) had metabolic syndrome, and 517 prostate cancers were diagnosed. A greater percentage of metabolic syndrome was found among patients with prostate cancer than among patients without prostate cancer (25% vs. 18%; P=.002). Poorer results were found in the radical prostatectomy specimens (Gleason score ≥ 7, P<.001; stage ≥ T2c, P<.001; positive surgical margins, P<.001), and there was a greater percentage of biochemical recurrence in patients with metabolic syndrome than in those without metabolic syndrome (24% vs. 13%; P=.003). Metabolic syndrome behaved as an independent predictive factor of finding a Gleason score ≥ 7 for the specimen, as well as for finding a specimen stage ≥ T2c. Metabolic syndrome was also able to independently predict a greater rate of biochemical recurrence (OR: 3.6, P<.001; OR: 3.2, P=.03; HR: 1.7; respectively).

CONCLUSIONS

Metabolic syndrome is associated with poorer findings in the radical prostatectomy specimens and is an independent prognostic factor of biochemical recurrence.

Poor glycemic control is associated with reduced prostate specific antigen concentrations in men with type 1 diabetes

PURPOSE

Previous studies have revealed lower prostate specific antigen concentrations in men with type 2 diabetes, paralleling the reported lower prevalence of prostate cancer in diabetic men. Data are lacking on prostate specific antigen in men with type 1 diabetes whose insulin and obesity profiles differ from those with type 2 diabetes mellitus. In this study we examined the relationship between long-term glycemic control and prostate specific antigen in men with type 1 diabetes mellitus.

MATERIALS AND METHODS

Total prostate specific antigen was measured at one time in 639 men in the EDIC, the observational followup of participants in the DCCT. The relationship between DCCT/EDIC weighted mean hemoglobin A1c and log prostate specific antigen was assessed using linear regression modeling after adjusting for age, body mass index, total testosterone, statin and thiazide medication use, diabetes duration, and DCCT randomization arm and cohort.

RESULTS

Median subject age was 52 years, body mass index was 28.4 kg/m(2) and DCCT/EDIC time-weighted hemoglobin A1c was 7.9%. Median prostate specific antigen was 0.64 ng/ml (IQR 0.43, 1.05). Prostate specific antigen increased significantly with age (p <0.0001) and with lower time-weighted hemoglobin A1c (p <0.0001). Each 10% increase in hemoglobin A1c was accompanied by an 11% reduction in prostate specific antigen (p=0.0001).

CONCLUSIONS

Prostate specific antigen decreases as hemoglobin A1c increases in men with type 1 diabetes mellitus. This relationship is independent of age, body mass index, androgen levels, medication use and measures of diabetes severity, which suggests that factors related to glycemia may directly affect prostate specific antigen levels.

Diabetes protects from prostate cancer by downregulating androgen receptor: new insights from LNCaP cells and PAC120 mouse model

Type 2 diabetes has been associated with decreased risk of prostate cancer in observational studies, and this inverse association has been recently confirmed in several large cohort studies. However the mechanisms involved in this protective effect remain to be elucidated. The aim of the present study was to explore whether different features of type 2 diabetes (hyperinsulinemia, hyperglycemia and tumor necrosis factor alpha [TNF-α]) protect against the development of prostate cancer. For this purpose LNCaP cells were used for in vitro experiments and nude mice in which PAC120 (hormone-dependent human prostate cancer) xenografts had been implanted were used for in vivo examinations. We provide evidence that increasing glucose concentrations downregulate androgen receptor (AR) mRNA and protein levels through NF-κB activation in LNCaP cells. Moreover, there was a synergic effect of glucose and TNFα in downregulating the AR in LNCaP cells. By contrast, insulin had no effect on AR regulation. In vivo experiments showed that streptozotocin-induced diabetes (STZ-DM) produces tumor growth retardation and a significant reduction in AR expression in PAC120 prostate cancer mice. In conclusion, our results suggest that hyperglycemia and TNF-α play an important role in protecting against prostate cancer by reducing androgen receptor levels via NF-κB.

Diabetes mellitus and prostate cancer risk; a nationwide case-control study within PCBaSe Sweden

BACKGROUND

Diabetes mellitus (DM) increases the risk for cancer at almost all sites, but data on the association with prostate cancer are inconsistent.

METHODS

We assessed the risk of a prostate cancer diagnosis among men with type 2 (T2)DM in a nationwide population-based case-control study including 44,352 men with prostate cancer identified through the Prostate Cancer data Base Sweden (PCBaSe) between 2002 and 2006 and 221,495 age-matched men from the general population.

RESULTS

Overall, the risk of prostate cancer among men with T2DM was lower than among men without T2DM [OR, 0.80; 95% confidence interval (CI), 0.76-0.85]. The risk decreased with longer disease duration and was observed across all tumor risk categories, although most clearly among men with low risk tumors (OR, 0.71; 95% CI, 0.64-0.80). The risk for prostate cancer was reduced among diabetic men on dietary treatment only (OR, 0.89; 95% CI, 0.80-0.99) but more markedly among men on oral hypoglycemic agents (OR, 0.80; 95% CI, 0.74-0.87) and insulin (OR, 0.72; 95% CI, 0.69-0.81). Obese diabetic men (BMI > 30 kg/m(2)) showed a reduced risk (OR, 0.72; 95% CI, 0.65-0.80) compared with men without diabetes. There was a trend of decreasing risk with increasing levels of HbA1c (P < 0.05).

CONCLUSIONS

This nationwide study confirmed a reduced risk of being diagnosed with prostate cancer among men with T2DM, especially for low-risk tumors. An altered hormonal milieu is a plausible explanation, although the possibility of decreased prostate cancer detection among diabetic men cannot be ruled out.

IMPACT

This is the largest study to examine the association between T2DM and prostate cancer accounting for tumor risk group and diabetes treatment.

New players for advanced prostate cancer and the rationalisation of insulin-sensitising medication

Obesity and type 2 diabetes are recognised risk factors for the development of some cancers and, increasingly, predict more aggressive disease, treatment failure, and cancer-specific mortality. Many factors may contribute to this clinical observation. Hyperinsulinaemia, dyslipidaemia, hypoxia, ER stress, and inflammation associated with expanded adipose tissue are thought to be among the main culprits driving malignant growth and cancer advancement. This observation has led to the proposal of the potential utility of "old players" for the treatment of type 2 diabetes and metabolic syndrome as new cancer adjuvant therapeutics. Androgen-regulated pathways drive proliferation, differentiation, and survival of benign and malignant prostate tissue. Androgen deprivation therapy (ADT) exploits this dependence to systemically treat advanced prostate cancer resulting in anticancer response and improvement of cancer symptoms. However, the initial therapeutic response from ADT eventually progresses to castrate resistant prostate cancer (CRPC) which is currently incurable. ADT rapidly induces hyperinsulinaemia which is associated with more rapid treatment failure. We discuss current observations of cancer in the context of obesity, diabetes, and insulin-lowering medication. We provide an update on current treatments for advanced prostate cancer and discuss whether metabolic dysfunction, developed during ADT, provides a unique therapeutic window for rapid translation of insulin-sensitising medication as combination therapy with antiandrogen targeting agents for the management of advanced prostate cancer.

Opium consumption is negatively associated with serum prostate-specific antigen (PSA), free PSA, and percentage of free PSA levels

Addiction to opium continues to be a major worldwide medical and social problem. The study addressing the association between opium consumption and serum prostate-specific antigen (PSA) level is lacking. We determined the effects of opium consumption on serum PSA levels in opium-addict men. Our study subjects comprised 438 opium-addict men with a mean age of 52.2 ± 6.4 years (group 1). We compared these men with 446 men who did not indicate current or past opium use (group 2). Serum total PSA (tPSA), free PSA (fPSA), % fPSA, and sex hormones were compared between the 2 groups. The mean serum tPSA level was significantly lower in group 1 (1.05 ng/mL) than in controls (1.45 ng/mL) (P = 0.001). Opium consumption was also associated with lower fPSA (P = 0.001) and % fPSA (P = 0.001). Serum free testosterone level in opium-addict patients (132.5 ± 42 pg/mL) was significantly lower than that in controls (156.2 ± 43 pg/mL) (P = 0.03). However, no significant correlation existed between tPSA and free testosterone levels (r = 0.28, 95% CI, -0.036 to 0.51, P = 0.34). Among the patients with cancer in group 1, 35% were found to have high-grade tumor (Gleason score ≥ 7) compared with 26.7% in group 2 (P = 0.02). Total PSA and fPSA were strongly correlated with duration of opium use (r = -0.06, 95% CI, -0.04 to -0.08, P = 0.0001; and r = -0.05, 95% CI, -0.03 to -0.07, P = 0.0001, respectively). Opium consumption is independently and negatively associated with serum tPSA, fPSA, and % fPSA levels.

Effects of EPA, γ-linolenic acid or coenzyme Q10 on serum prostate-specific antigen levels: a randomised, double-blind trial

The main objective of the present study was to determine the potential of n-3 and n-6 fatty acids or coenzyme Q10 (CoQ10) to alter serum prostate-specific antigen (PSA) levels in normal healthy men. A total of 504 healthy men with serum PSA level ≤ 2·5 ng/ml were recruited into the study. Serum PSA values were not segregated by decade of age. Participants were randomly assigned to a daily dietary supplement containing n-3 fatty acids (1·12 g of EPA and 0·72 g of DHA per capsule) (group 1, n 126), n-6 fatty acid (600 mg γ-linolenic acid (GLA) each capsule) (group 2, n 126), CoQ10 (100 mg per capsule) (group 3, n 126) or a similar regimen of placebo (group 4, n 126) for 12 weeks. Study medication was administered as two capsules to be taken twice daily. Serum levels of PSA, EPA, DHA, GLA, lipid profile and reproductive hormones were also measured. EPA treatment significantly reduced serum PSA level by 30·0 (95 % CI 25, 36) % (P= 0·004) from baseline. In contrast, GLA therapy significantly increased serum PSA concentration by 15·0 (95 % CI 11, 20) % (P= 0·02). CoQ10 therapy also significantly reduced serum PSA level by 33·0 (95 % CI 27, 40) % (P= 0·002). In multivariable analysis, serum values of PSA were strongly correlated with duration of EPA (r - 0·62; 95 % CI - 0·42, - 0·77; P= 0·003), n-6 (r 0·42; 95 % CI 0·31, 0·58; P= 0·02) and CoQ10 use (r - 0·77; 95 % CI - 0·56, - 0·87; P= 0·001). There were also significant correlations between serum values of DHA, EPA, GLA and CoQ10 and serum PSA levels. The present study demonstrates that dietary supplements containing EPA, GLA or CoQ10 may significantly affect serum PSA levels.

Diabetic nephropathy is associated with prostate-specific antigen levels in type 2 diabetes mellitus

PURPOSE

Type 2 diabetes is associated with reduced risk of prostate cancer and low prostate-specific antigen levels for uncertain reasons. Recently, two studies demonstrated the time course of diabetes with prostate-specific antigen levels, which would be explained by the chronic renal complication. Therefore, we conducted a retrospective study to determine whether diabetic nephropathy is associated with prostate-specific antigen levels.

METHODS AND RESULTS

Eligible patients were men aged ≥40 years, with type 2 diabetes and a recorded prostate-specific antigen level. Patients with a prior history of prostate cancer or prostatectomy or prostate-specific antigen level ≥10 ng/mL and patients with end-organ damage were excluded. Of the 247 patients included in the adjusted analysis, 51 (20.8 %) were diagnosed with diabetic nephropathy. A significant association of diabetic nephropathy with log-transformed prostate-specific antigen level was detected (Spearman's correlation coefficient -0.201, p = 0.003; adjusted for all other correlated variables) and fit into a linear regression model (B-coefficient -0.331, p = 0.003). Comparing diabetic nephropathy group with non-diabetic nephropathy group, the difference in log-transformed prostate-specific antigen levels was also significant (p = 0.002).

CONCLUSION

The results indicated that patients with diabetic nephropathy have low prostate-specific antigen levels, suggesting fewer prostate cancers being detected or fewer incidences among this group.

Association of obesity and diabetes with serum prostate-specific antigen levels in Japanese males

Patients with diabetes have been reported to be at an increased risk for cancers of the pancreas, liver, and colon; however, recent studies have suggested that men with diabetes are at a decreased risk for prostate cancer. Previous studies have found that obese men have lower serum prostate-specific antigen (PSA) concentrations than do non-obese men. Further understanding of how obesity and diabetes affect the PSA concentration may improve our ability to detect clinically relevant prostate tumors. This study examined the relationships among serum PSA level, obesity, and diabetes in apparently healthy Japanese males. We analyzed the baseline data from 2,172 Japanese males (age, 56.8 +/- 6.1 years [mean +/- SD]) who participated in the Japan Multi-Institutional Collaborative Cohort Study. Diabetes was defined as the presence of both a hemoglobin A1c (JDS) of > or = 6.1% and a fasting plasma glucose level of > or = 126 mg/dL, or a positive medical history. After adjusting for age, the PSA levels were elevated among males with a higher normal BMI (ranging from 23.0 to 24.9) and lowered among men with a BMI of > or = 25.0. In the stratified analysis, these significant differences in BMI categories were absent among diabetics. The mean PSA levels were significantly lower in diabetics than in non-diabetics among subjects aged 60 and over. Our findings suggest that the pre-overweight men had increased PSA levels, and the diabetes was associated with a reduction of PSA levels in elderly.

Prostate carcinogenesis with diabetes and androgen-deprivation-therapy-related diabetes: an update

Prostate cancer and the androgen deprivation therapy (ADT) thereof are involved in diabetes in terms of diabetes-associated carcinogenesis and ADT-related metabolic disorder, respectively. The aim of this study is to systematically review relevant literature. About 218,000 men are estimated to be newly diagnosed with prostate cancer every year in the United States. Approximately 10% of them are still found with metastasis, and in addition to them, about 30% of patients with nonmetastatic prostate cancer recently experience ADT. Population-based studies have shown that dissimilar to other malignancies, type 2 diabetes is associated with a lower incidence of prostate cancer, whereas recent large cohort studies have reported the association of diabetes with advanced high-grade prostate cancer. Although the reason for the lower prevalence of prostate cancer among diabetic men remains unknown, the lower serum testosterone and PSA levels in them can account for the increased risk of advanced disease at diagnosis. Meanwhile, insulin resistance already appears in 25–60% of the patients 3 months after the introduction of ADT, and long-term ADT leads to a higher incidence of diabetes (reported hazard ratio of 1.28–1.44). Although the possible relevance of cytokines such as Il-6 and TNF-α to ADT-related diabetes has been suggested, its mechanism is poorly understood.

Serum prostate specific antigen changes in cynomolgus monkeys (Macaca fascicularis) on a high sugar high fat diet

BACKGROUND

An inverse relationship between serum prostate specific antigen (PSA) levels and body mass index (BMI) has been reported in men but not in any animal model.

METHODS

Serum PSA in a colony of cynomolgus monkeys was assayed and correlated to body weight, prostate weight, and age. In addition, 15 animals were selected and fed a high sugar high fat (HSHF) diet for 49 weeks to increase their BMI and correlate it to PSA RESULTS: Serum PSA levels were positively correlated to prostate weight (r = 0.515, P = 0.025) and age (r = 0.548, P = 0.00072) but was not significantly correlated to body weight (r = -0.032, P = 0.419). For the animals on the HSHF diet, body weight, lean mass, fat mass, and BMI were significantly higher at 49 weeks than at baseline (P < 0.01). PSA was not significantly correlated to body weight and insulin at both baseline and 49 weeks. PSA was negatively correlated to BMI and insulin resistance (HOMA-IR) at 49 weeks but not at baseline. In addition, we observed hepatic steatosis and increases in serum liver enzymes.

CONCLUSIONS

Increases in BMI in cynomolgus monkeys as a result of consuming a HSHF diet resulted in PSA changes similar to those in humans with increased BMI. Cynomolgus monkeys are a useful model for investigating the relationship between obesity, diabetes, and PSA changes resulting from prostate gland pathology.

The association of diabetes and positive prostate biopsy in a US veteran population

BACKGROUND

Several studies have shown a protective effect of diabetes mellitus (DM) on incidence of prostate cancer; however, the data are not consistent. Moreover, whether or not DM is associated with a positive result among patients referred for prostate biopsy due to abnormal PSA and/or abnormal digital rectal examination is not clear.

METHODS

A retrospective review of 3162 consecutive men who underwent prostate biopsy between January 2000 and July 2009 at the Atlanta Veterans Affairs Medical Center was performed. Men with positive and negative biopsies were compared for various demographic and clinical factors. The data were analyzed using logistic regression models with results expressed as adjusted odds ratios (ORs) with corresponding 95% confidence intervals (CI).

RESULTS

DM was associated with increased odds of positive biopsy in the overall cohort (OR 1.26, 95% CI: 1.01-1.55; P = 0.04). Subjects with DM had higher odds of more aggressive disease (Gleason ≥ 7) than those without the condition (OR 1.31, 95% CI: 0.98-1.74; P = 0.07). Race had no significant impact on these results.

CONCLUSIONS

In this large series of prostate biopsies, diabetes is associated with higher odds of positive biopsy and higher Gleason grade. More studies investigating the role of DM and its associated comorbidities in prostate carcinogenesis are needed.

Insulin therapy in diabetes and cancer risk: current understanding and implications for future study: proceedings from a meeting of a European Insulin Safety Consensus Panel, convened and sponsored by Novo Nordisk, held Tuesday October 5, 2010 at The Radisson Edwardian Heathrow Hotel, Hayes, Middlesex, UK

INTRODUCTION

Interest in the possibility of certain insulin treatments having the potential to modify cancer development and prognosis was reawakened in 2009, following publication of several epidemiological studies addressing this issue. This interest extends to how diabetes itself and cancer might be linked, and makes desirable an exchange of expert views and knowledge to enhance understanding in this subject among those treating diabetes and cancer, or those developing diabetes therapies.

METHODS

A European meeting was convened with participants invited based on known relevant interests in endocrinology, oncology, epidemiology, and insulin analog design and investigation. Experts in these fields were invited to present on relevant topics, with open discussions held after each presentation.

RESULTS

Concern over the potential mitogenic properties of certain insulin analogs has arisen from some (but not all) epidemiological studies, although confounding factors render interpretation controversial. Future epidemiological studies are likely to strengthen confidence in drawing conclusions. Meanwhile, pharmacological studies, and a consideration of cancer pathophysiology, implicate increased insulin-like growth factor-1 receptor affinity, and/or deranged insulin receptor interaction/signaling properties as possible a priori causes for concern with some insulin analogs. Again, interpretation of the body of pharmacological evidence is confounded by the array of test systems and methodologies used, and by studies frequently succumbing to methodological pitfalls. Reassuringly, most available insulin analogs do not differ in their receptor interaction response profile to human insulin, and for those that do there are reasons to question any potential clinical relevance. Nevertheless, it is desirable that new experimental models are devised that can better determine the likely clinical consequences of any variance in receptor response profile versus human insulin.

CONCLUSION

More data are required to increase our understanding of this issue. To facilitate and disseminate such understanding, close cooperation and communication between diabetologists, epidemiologists, oncologists, and insulin engineers will be essential.