Observed effect of age and body mass index on total and complexed PSA: analysis from a national screening program

Association between obesity and frequency of high‑grade prostate cancer on biopsy in men: A single‑center retrospective study

The present study aimed to investigate the relationship between BMI and the prostate cancer (PCa) risk at biopsy in Italian men. Retrospective analyses of the clinical data of 2,372 consecutive men undergoing ultrasound-guided multicore (≥10) prostate biopsy transrectally between May 2010 and December 2018 were performed. BMIs were categorized, according to Western countries' classification of obesity, as follows: <18.5 kg/m² (underweight), 18.5-24.99 kg/m² (normal weight), 25-30 kg/m² (overweight) and >30 kg/m² (obese). The distribution of patients undergoing biopsy was compared with a model population from the official survey data. Patient characteristics and the relationships between characteristics were investigated using correlation analysis, ANOVA, Kruskal-Wallis and Dunn's tests. The present study estimated the influence on cancer incidence not only of BMI but also of other patient characteristics using multi-variable logistic modelling and compared, using the models, the expected outcomes for patients who differed only in BMI. From a sample of 2,372 men, the present study enrolled 1,079 men due to a lack of clinical data [such as prostate specific antigen (PSA) and BMI data] in the other patients undergoing prostate biopsy. Their distribution was significantly different from the model distribution with the probability of undergoing biopsy increasing with increasing BMI. The median age was 69.4 years. The median BMI was 26.4 kg/m², while the median PSA level was 7.60 ng/ml. In total, the biopsies detected PCa in 320 men (29.7%) and high-grade PCa (HGPCa) in 218 men (20.2%). Upon applying the aforementioned Western countries' criteria for BMI categories, there were 4 (0.4%) underweight, 318 (29.5%) of normal weight, 546 (50.6%) overweight, and 211 (19.6%) obese patients. ANOVA/Kruskal-Wallis tests revealed that overweight and obese men were younger than the normal-weight men, while there was no statistical difference in their PSA values. Furthermore, 29.3% of normal-weight men, 29.5% of overweight men and 29.9% of obese men were diagnosed with PCa, while 19.5% of normal-weight men, 20.1% of overweight men and 21.8% of obese men were affected by severe cancer. BMI was found to be positively correlated with PCa risk and negatively correlated with both age and PSA level. Age and PSA level were both positively correlated with PCa risk, while digital rectal examination (DRE) outcome was strongly indicative of PCa discovery if the test outcome was positive. Logistics models attributed a positive coefficient to BMI when evaluated against both PCa risk and HGPCa risk. In patients having a negative DRE outcome who differed only in BMI, logistic regression showed a 60% increased risk of PCa diagnosis in obese patients compared with in normal-weight patients. This risk difference increased when other characteristics were less indicative of PCa (younger age/lower PSA), while it decreased when patient characteristics were more indicative (older age/higher PSA, positive DRE). In conclusion, the present study demonstrated that, in men with higher BMIs, the risk of PCa is higher. The relative difference in risk between low and high BMI is most pronounced in younger patients having a lower PSA level and a negative DRE outcome.

Association between Serum Triglycerides and Prostate Specific Antigen (PSA) among U.S. Males: National Health and Nutrition Examination Survey (NHANES), 2003-2010

(1) Background: Increasing evidence indicates that lipid metabolism may influence the concentration of prostate-specific antigen (PSA). However, the association between triglycerides and PSA remains unclear and complicated. Hence, we evaluated the correlation between triglycerides and PSA based on the U.S. National Health and Nutrition Examination Survey (NHANES) database. (2) Methods: A total of 2910 participants out of 41,156 participants fit into our study after conducting the screening from the 2003 to 2010 NHANES survey. Serum triglycerides were the independent variable of our study, and PSA was the dependent variable; (3) Results: In our study, the average age of chosen participants was 59.7 years (±12.7). After adjusting for covariates, the result indicated that for each additional unit of serum triglyceride (mg/dL), the PSA concentrations were reduced by 0.0043 ng/mL (−0.0082, −0.0005) with a statistical difference. Furthermore, we used machine learning of the XGBoost model to determine the relative importance of selected variables as well as constructed a smooth curve based on the fully adjusted model to investigate the possible linear relationship between the triglyceride and PSA concentrations. (4) Conclusions: The serum triglyceride is independently and negatively correlated with PSA among American males, which may make it hard to detect asymptomatic prostate cancer and diagnose at an advance stage with higher triglycerides due to detection bias.

Association of Total Dietary Intake of Sugars with Prostate-Specific Antigen (PSA) Concentrations: Evidence from the National Health and Nutrition Examination Survey (NHANES), 2003-2010

BACKGROUND

There is increasing evidence that dietary intake of sugars may be a risk factor for prostate cancer (PCa) and elevate the concentration of serum prostate-specific antigen (PSA). However, there is limited evidence of the correlation between total dietary intake of sugars and serum PSA concentrations for adult American males. Herein, we evaluated the association between total dietary intake of sugars and serum PSA concentrations in men without a malignant tumor diagnosis in the United States (US) National Health and Nutrition Examination Survey (NHANES) database. Material and Methods. In this secondary data analysis, a total of 6,403 men aged ≥40 years and without malignant tumor history were included from 2003 to 2010. The independent variable of this study was the total dietary intake of sugars, and the dependent variable was serum PSA concentrations. Covariates included dietary, comorbidity, physical examination, and demographic data.

RESULTS

The average age of participants included in this study was 58.1 years (±13.6). After adjusting for the dietary, comorbidity, physical examination, and demographic data, we observed that a dietary intake increase of one gram of total dietary intake of sugars was associated with an increase of serum PSA concentrations by 0.003 ng/mL (after log2 transformed, 95% CI: 0.001 to 0.005) with a P value for trend less than 0.05. Sensitivity analysis using the generalized additive model (GAM) supported the linear association between total dietary intake of sugars and serum PSA concentrations.

CONCLUSION

The total dietary intake of sugars is independently and positively associated with serum PSA concentrations in adult American males who are without a personal history of malignant tumors.

Prostate-specific antigen and (free prostate-specific antigen/ prostate-specific antigen) ratio in patients with Benign Prostatic Hyperplasia and Prostate Cancer

Background: Prostate cancer is one of the most common cancers in menworldwide. Many markers are suggested as markers of prostate cancer with differentspecificity and sensitivity.Objective : The present study’s main aim is to examine the possible utility ofprostate-specific antigen indices as markers of prostate cancer.Methods: A case-control study was conducted in the Department of Chemistry andBiochemistry, College of Medicine, Al- Nahrain University, Baghdad, Iraq from July2018 till March 2019, includes 84 subjects divided into three groups:Twenty Four patients with prostate cancer (PCA), thirty patients with benignprostatic hyperplasia (BPH) and thirty healthy subjects as a control group wereexamined in this study.Thirty healthy volunteer subjects were asked to be involved in this study as a controlgroup. Blood samples from these patients were collected before obtaining a prostaticbiopsy. Serum PSA, fPSA levels were quantified by the ELISA technique.Results: PSA cut-off value was found to be more than 9.57 ng/ml for Prostate Cancerpatients, values range between 3.17 - 9.57 ng/ml for BPH patients and cut-off valuefor control was found to be less than 3.17 ng/ml, while serum (fPSA/PSA) % cut-offvalue was less than 11.1% for Prostate Cancer patients, values range between 11.1% -31 % for BPH patients, and cut-off value was greater than 31% for the control group.Conclusion: There is a highly significant difference in serum PSA levels and(fPSA/PSA)% between the prostate cancer and control groups. Body mass indexshowed an inverse association with the risk of prostate cancer.

Relationship between body mass index and concentrations of prostate specific antigen: a cross-sectional study

The possible relationship between body mass index (BMI) and prostate-specific antigen (PSA) concentrations is controversial. The objective of this study was to assess the relationship between BMI and PSA concentrations in Chinese men. A total of 81,122 men who had undergone annual medical examinations at the First Affiliated Hospital of Army Medical University between 1 January 2011 and 31 December 2018 were included. Univariate and multivariate linear regression models were used to assess the relationship between BMI and PSA concentrations. The nonlinear relationship was analyzed using a generalized additive model with a spline smoothing function. Subsequently, a stratified linear regression model was used for subgroup analysis. The mean age and BMI of the participants were 45.91 ± 12.21 years and 24.79 ± 3.11 kg/m², respectively. After adjustment for age, waist circumference-hip circumference ratio, systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase and aspartate aminotransferase, BMI was negatively related to PSA level (p < .001). A nonlinear relationship was detected, and different relationships between BMI and PSA concentrations were observed on each side of the inflection point (BMI = 23.11 kg/m²). Our study revealed an inverse, nonlinear relationship between BMI and PSA concentrations. Thus, this relationship may be a concern when establishing reference intervals or decision limits for PSA concentrations.

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.

Night shiftwork and prostate-specific antigen level in a tire manufacturing factory

BACKGROUND

Recent studies suggest that night shiftwork may increase the risk of prostate cancer and elevated serum prostate-specific antigen (PSA) level. The purpose of this study was to verify whether rotating night shiftwork affects serum PSA level.

METHODS

This study included 3,195 male production workers who work in a large tire manufacturing factory. Serum PSA levels were measured and the data on related factors were obtained.

RESULTS

The mean serum PSA level was 0.98 ± 0.79 ng/mL. PSA levels were significantly lower in the younger age group, the obese group, and regular exercise group. PSA levels were lower in night shift workers (n = 2,832) compared to day workers (n = 363), but the difference was not statistically significant.

CONCLUSIONS

Unlike previous studies, we did not find any evidence that night shiftwork results in an increase in serum PSA levels. Further research and consistent results are needed to elucidate the association between night shiftwork and the effect on the prostate.

Nutrition, physical activity, and lifestyle factors in prostate cancer prevention

PURPOSE OF REVIEW

To review current evidence for prostate cancer prevention with nutrition, physical activity, and lifestyle interventions and identify future research directions.

RECENT FINDINGS

Multiple preclinical and observational studies have observed that diet, exercise, and lifestyle interventions may play a role in mitigating disease progression, mortality, and overall disease burden for high-grade and fatal prostate cancer. Increased vegetable and fruit intakes, decreased red meat and saturated fat intakes, and increased exercise are potentially associated with decreased risk of incident disease and increased progression-free, prostate cancer-specific, and overall survival. Randomized controlled trials (RCTs) have demonstrated that selenium and vitamin C supplements are ineffective in preventing incident prostate cancer and that vitamin E supplements potentially increase incident prostate cancer risk. A large RCT of a high vegetable diet intervention among prostate cancer patients on active surveillance, the Men's Eating and Living study, will soon complete analysis. An RCT for an exercise intervention among men with metastatic castrate-resistant prostate cancer is currently accruing.

SUMMARY

Although preclinical and observational studies have identified potential benefits for high vegetable, low fat, low meat diets, and increased exercise, Level I evidence is limited. To inform clinical care, future research should focus on RCTs evaluating clinical effectiveness.

Obesity suppresses tumor attributable PSA, affecting risk categorization

Obesity is linked with more aggressive prostate cancer and higher rates of disease recurrence post treatment. It is unclear if this is due to specific tumor-promoting effects of obesity or diagnostic bias. Patients undergoing prostatectomy were categorized according to their body mass index (BMI). Expected prostate-specific antigen (PSA) levels were calculated for each patient based on tumor characteristics. The effect of obesity on the accuracy of pre-treatment risk categorization was determined, and mediation analysis was used to identify the contribution of biologic vs non-biologic mechanisms to the observed increased risk of biochemical recurrence. Residual tumor-promoting effects were estimated in a survival model controlling for diagnostic error. The following results were obtained. The analysis included 1587 patients. Despite similar rates of adverse pathological features at prostatectomy, biochemical recurrence rates were significantly higher in very obese patients, which persisted after adjustment for stage, grade and PSA. Tumor volume however correlated significantly with BMI (P = 0.004), and the difference in predicted and observed 'tumor-attributable' PSA (Delta-PSA) in very obese patients was greater than three times higher than that of healthy patients (P = 0.0067). Regression analysis indicated that the effect of BMI on tumor volume was fully mediated indirectly by its effect on PSA. Inclusion of this diagnostic error as a covariate in the survival analysis attenuated the effect of BMI on recurrence. In conclusion, being very obese suppresses tumor-associated PSA resulting in a diagnostic bias that is responsible for errors in risk classification, and potentially contributes to a delay in initial presentation.

Clinical and biochemical markers of visceral adipose tissue activity: Body mass index, visceral adiposity index, leptin, adiponectin, and matrix metalloproteinase-3. Correlation with Gleason patterns 4 and 5 at prostate biopsy

Context:

The correlation between aggressive prostate cancer and obesity mainly based on body mass index (BMI) and pathology after surgery remains controversial.

Aims:

The aim of the study was to correlate BMI, visceral adiposity index (VAI), and the plasmatic levels of leptin, adiponectin, and matrix metalloproteinase-3 (MMP-3), and biomarkers of adipose tissue function, with the detection of Gleason patterns 4 and 5 at biopsy.

Subjects and Methods:

Consecutive patients with prostate cancer at 12-core transrectal biopsy were enrolled. BMI, waist circumference (WC), blood samples to evaluate the plasmatic levels of triglycerides (TG) and high-density lipoproteins (HDL), adiponectin, leptin, and MMP-3 were obtained immediately before biopsy. The VAI was calculated according to the formula: WC/(39.68 + [1.88 × BMI]) × TG/1.03 × 1.31/HDL.

Results:

One hundred and forty-nine patients were entered. The median PSA, BMI, and VAI were 10.0 ng/ml, 27.6 kg/m², and 4.6, respectively. Gleason patterns 4 or 5 were detected in 68 (45.6%) patients; in 15 (41.7%), 31 (44.9%), and 22 (50.0%) among normal weight, overweight, and obese patients, respectively (P = 0.55). The statistical analysis did not show any significant correlation between BMI, VAI, the plasmatic levels of leptin, adiponectin, MMP-3, and the detection of Gleason patterns 4 and 5 at biopsy. A statistically significant association emerged with older age (P = 0.017) and higher PSA values (P = 0.02).

Conclusion:

We did not find any association between BMI, VAI, the plasmatic levels of adiponectin, leptin, and MMP-3 and the detection of Gleason patterns 4 and 5 at prostate biopsy.

Impact of poor glycemic control of type 2 diabetes mellitus on serum prostate-specific antigen concentrations in men

BACKGROUND

To evaluate the impact of poor glycemic control of type 2 diabetes mellitus (T2DM) on serum prostate-specific antigen (PSA) concentrations in men.

METHODS

We performed a prospective analysis of 215 consecutive patients affected by erectile dysfunction (ED). ED was evaluated using the IIEF-5 questionnaire and the poor glycemic control (PGC) of T2DM was assessed according to the HbA1c criteria (International Diabetes Federation). Patients were divided into PGC group (HbA1c ≥ 7%) and control group (CG) (HbA1c < 6%). Correlations between serum HbA1c levels and various variables were evaluated and multivariate logistic regression analyses were carried out to identify variables for PGC.

RESULTS

We compared 110 cases to 105 controls men ranging from 44 to 81 years of age, lower PSA concentrations were observed in men with PGC (PGC mean PSA: 0.9 ng/dl, CG mean PSA: 2.1 ng/dl, p < 0.001). Also mean prostate volume was 60% was smaller among men with PGC compared with men with CG (PGC mean prostate volume: 26 ml, CG prostate volume: 43 ml, p < 0.001). A strong negative correlation was found between serum HbA1c levels and serum PSA (p < 0.001 and r = -0.665) concentrations in men with PGC. We also found at the multivariate logistic regression model that PSA, prostate volume and peak systolic velocity were independent predictors of PGC.

CONCLUSION

Our results suggest that there is significant impact of PGC on serum PSA levels in T2DM. Poor glycemic control of type 2 diabetes was associated with lower serum PSA levels and smaller prostate volumes.

PSA and Prostate Health Index based prostate cancer screening in a hereditary migration complicated population: implications in precision diagnosis

Precision diagnosis requires specific markers for differential ethnic populations. Prostate-Specific Antigen (PSA) level (threshold of 4ng/ml) has been widely used to screen prostate cancer and as reference of pro-biopsy but false diagnosis frequently occurs. Prostate health Index (PHI) is a new diagnosis marker which combines PSA, free PSA and p2PSA4. Overall the PCa screening database is lacking in Kazakhstani patients. We analyzed the PSA levels and Gleason scores of 222 biopsies collected in 2015 in Almaty area, Kazakhstan approved by institutional ethics board. We found using PSA of 4ng/ml as threshold, only 25.68% of patients have cancer with Gleason score ranged 6-8 and 65.77% of patients have no character of cancer. Moreover, there is no significant correlation between PSA and cancerous (P=0.266) or Gleason grade (P=0.3046) based on pathological biopsy. In addition, PHI is not correlated to prostate cancer (P=0.4301). Our data suggest that false-positive rate is much higher than the correct-positive diagnosis when using PSA as the first screening. Thus in this cohort study, most patients can not get benefit from the PSA screening for precision PCa diagnosis. As Kazakhstani family trees are unique and complicated because of history and migration, the high rate of over diagnosis might be due to the hyperexpression of PSA via heterosis in Eurasian men. Therefore we should be cautious when using pro-biopsy in precision diagnosis for Eurasian prostate cancer patients.

Obesity and prostate cancer-specific mortality after radical prostatectomy: results from the Shared Equal Access Regional Cancer Hospital (SEARCH) database

Background:

At the population level, obesity is associated with prostate cancer (PC) mortality. However, few studies analyzed the associations between obesity and long-term PC-specific outcomes after initial treatment.

Methods:

We conducted a retrospective analysis of 4268 radical prostatectomy patients within the Shared Equal Access Regional Cancer Hospital (SEARCH) database. Cox models accounting for known risk factors were used to examine the associations between body mass index (BMI) and PC-specific mortality (PCSM; primary outcome). Secondary outcomes included biochemical recurrence (BCR) and castration-resistant PC (CRPC). BMI was used as a continuous and categorical variable (normal <25 kg/m², overweight 25–29.9 kg/m² and obese ⩾30 kg/m²). Median follow-up among all men who were alive at last follow-up was 6.8 years (interquartile range=3.5–11.0). During this time, 1384 men developed BCR, 117 developed CRPC and 84 died from PC. Hazard ratios were analyzed using competing-risks regression analysis accounting for non-PC death as a competing risk.

Results:

On crude analysis, higher BMI was not associated with risk of PCSM (P=0.112), BCR (0.259) and CRPC (P=0.277). However, when BMI was categorized, overweight (hazard ratio (HR) 1.99, P=0.034) and obesity (HR 1.97, P=0.048) were significantly associated with PCSM. Obesity and overweight were not associated with BCR or CRPC (all P⩾0.189). On multivariable analysis adjusting for both clinical and pathological features, results were little changed in that obesity (HR=2.05, P=0.039) and overweight (HR=1.88, P=0.061) were associated with higher risk of PCSM, but not with BCR or CRPC (all P⩾0.114) with the exception that the association for overweight was no longer statistical significant.

Conclusions:

Overweight and obesity were associated with increased risk of PCSM after radical prostatectomy. If validated in larger studies with longer follow-up, obesity may be established as a potentially modifiable risk factor for PCSM.

Effect of obesity on International Prostate Symptom Score and prostate volume

Aim:

The aim of this study was to investigate the relationship between obesity and lower urinary tract symptoms and prostate volume in patients who underwent prostate biopsies.

Materials and Methods:

Between December 2008 and November 2009, transrectal ultrasound-guided prostate biopsy was performed on patients who had elevated prostate-specific antigen levels or abnormal digital rectal examination findings. A total of 211 patients were included in this study. Prostate volumes, International Prostate Symptom Score (IPSS) values, and the patient's height and weight were all recorded during the biopsy. Body mass index (BMI) <18.5 was determined as underweight, 18.5–23.0 normal, 23.0–27.5 overweight, and >27.5 obese.

Results:

The mean age of the patients was 68.0 ± 6.3 years, and the mean BMI was 28.0 ± 4.9 kg/m². The mean prostate volume of the normal, overweight, and obese groups was 30, 50, and 70 ml, respectively. The positive and statistically significant correlation between BMI and prostate volume was determined (P < 0.001). According to BMI, the mean IPSS was 8.0, 16.5, and 20.0 in the groups, respectively. Similarly, a statistically positive correlation between BMI and IPSS was demonstrated (P < 0.001).

Conclusions:

As the result of a rise in BMI, prostate volumes and IPSS increase in patients. Prostate volume and IPSS decrease due to weight loss, and hence that fewer urinary symptoms occur, and the quality-of-life of patients may increase.

Clinical performance of the Prostate Health Index (PHI) for the prediction of prostate cancer in obese men: data from the PROMEtheuS project, a multicentre European prospective study

OBJECTIVES

To test serum prostate-specific antigen (PSA) isoform [-2]proPSA (p2PSA), p2PSA/free PSA (%p2PSA) and Prostate Health Index (PHI) accuracy in predicting prostate cancer in obese men and to test whether PHI is more accurate than PSA in predicting prostate cancer in obese patients.

PATIENTS AND METHODS

The analysis consisted of a nested case-control study from the pro-PSA Multicentric European Study (PROMEtheuS) project. The study is registered at http://www.controlled-trials.com/ISRCTN04707454. The primary outcome was to test sensitivity, specificity and accuracy (clinical validity) of serum p2PSA, %p2PSA and PHI, in determining prostate cancer at prostate biopsy in obese men [body mass index (BMI) ≥30 kg/m(2) ], compared with total PSA (tPSA), free PSA (fPSA) and fPSA/tPSA ratio (%fPSA). The number of avoidable prostate biopsies (clinical utility) was also assessed. Multivariable logistic regression models were complemented by predictive accuracy analysis and decision-curve analysis.

RESULTS

Of the 965 patients, 383 (39.7%) were normal weight (BMI <25 kg/m(2) ), 440 (45.6%) were overweight (BMI 25-29.9 kg/m(2) ) and 142 (14.7%) were obese (BMI ≥30 kg/m(2) ). Among obese patients, prostate cancer was found in 65 patients (45.8%), with a higher percentage of Gleason score ≥7 diseases (67.7%). PSA, p2PSA, %p2PSA and PHI were significantly higher, and %fPSA significantly lower in patients with prostate cancer (P < 0.001). In multivariable logistic regression models, PHI significantly increased accuracy of the base multivariable model by 8.8% (P = 0.007). At a PHI threshold of 35.7, 46 (32.4%) biopsies could have been avoided.

CONCLUSION

In obese patients, PHI is significantly more accurate than current tests in predicting prostate cancer.

Obesity increases the risk for high-grade prostate cancer: results from the REDUCE study

BACKGROUND

Studies suggest that obesity is associated with lower risk of prostate cancer but more aggressive cancers. As obesity lowers PSA levels, these observations may be influenced by detection bias. We examined the association between obesity and risk of low- and high-grade prostate cancer in REDUCE, in which biopsies were largely independent of PSA.

METHODS

The REDUCE study tested dutasteride for prostate cancer risk reduction in men with a PSA of 2.5 to 10.0 ng/mL and a negative biopsy. Study participants included 6,729 men who underwent at least one on-study biopsy. The association between baseline body mass index (BMI <25 kg/m(2) normal weight; 25-29.9 kg/m(2) overweight; and ≥30 kg/m(2) obese) and risk of high-grade (Gleason ≥7) or low-grade prostate cancer (Gleason <7) versus no prostate cancer was examined using multinomial logistic regression.

RESULTS

Overall, 1,739 men (27%) were normal weight, 3,384 (53%) overweight, and 1,304 (20%) were obese. Obesity was associated with lower risk of low-grade prostate cancer in both univariable (OR, 0.74; P = 0.001) and multivariable analyses (OR, 0.79; P = 0.01). In univariable analysis, obesity was not associated with high-grade prostate cancer (OR, 1.08; P = 0.50). However, in multivariable analysis, obesity was associated with increased risk of high-grade prostate cancer (OR, 1.28; P = 0.042). This analysis was not able to address how obesity may influence prostate cancer progression.

CONCLUSIONS

Obesity is associated with decreased risk of low-grade and increased risk of high-grade prostate cancer. These data provide further support to the hypothesis that obesity is associated with aggressive prostate cancer.

IMPACT

Obesity is linked with aggressive prostate cancer. Avoiding obesity may prevent the risk of developing high-grade prostate cancer.

Association between obesity, prostate-specific antigen level and prostate-specific antigen density in men with a negative prostate biopsy

OBJECTIVE

To determine the association between body mass index (BMI), serum prostate-specific antigen (PSA) level and PSA density (PSAD) in patients with an elevated serum PSA level but a negative prostate biopsy.

METHODS

This retrospective study enrolled men with a negative prostate biopsy but a serum PSA level of 3.0-10 ng/ml. All men underwent anthropometric measurements, serum PSA determination and transrectal ultrasound examination. BMI was grouped according to the Asia-Pacific obesity criteria: nonobese (<25 kg/m(2)) versus obese (≥ 25 kg/m(2)). Partial correlation and linear regression models between PSA, PSAD and BMI were conducted after adjusting for age.

RESULTS

A total of 907 men were enrolled in this study. On multivariate analyses, PSA showed no significant correlation with age or BMI, whereas PSAD had a negative correlation with age and BMI. Similar results were obtained when patients were categorized as having low (3.0 < PSA  ≤ 6.5 ng/ml) or high PSA (6.5 < PSA ≤ 10.0 ng/ml) levels.

CONCLUSION

PSAD, but not PSA, demonstrated a significant negative correlation with BMI. This indicates that a new strategy including PSAD rather than simple PSA levels should be adopted in the study of obesity-adjusted PSA cut-offs.

Prostate-specific antigen mass and free prostate-specific antigen mass for predicting the prostate volume of korean men with biopsy-proven benign prostatic hyperplasia

PURPOSE

It has been reported that prostate-specific antigen (PSA) correlates with prostate volume. Recently, some studies have reported that PSA mass (PSA adjusted for plasma volume) is more accurate than PSA at predicting prostate volume. In this study, we analyzed the accuracy of PSA and the related parameters of PSA mass, free PSA (fPSA), and fPSA mass in predicting prostate volume.

MATERIALS AND METHODS

We retrospectively investigated 658 patients who underwent prostate biopsy from 2006 to 2012 and had a confirmed negative biopsy result. International Prostate Symptom Score (IPSS) questionnaire, PSA, fPSA, and prostate volume were investigated. PSA mass and fPSA mass were calculated by use of established formulas. The association between PSA-related parameters and IPSS and prostate volume was assessed by using Pearson correlation coefficient and receiver operating characteristic curves.

RESULTS

There was no significant difference between PSA and PSA mass, fPSA, or fPSA mass in predicting prostate volume except in obese patients (p-value of PSA-PSA mass for 40 cm(3), 0.54; p-value of fPSA-fPSA mass for 40 cm(3), 0.34). fPSA performed significantly better than PSA at predicting prostate volume (p-value for 40 cm(3), <0.001). IPSS and the aforementioned PSA-related parameters were not significantly correlated.

CONCLUSIONS

PSA mass was not a better predictive value than PSA for estimating the prostate volume in Korean men except in obese men. This finding was also applicable to the relationship of fPSA and fPSA mass, which appeared to be more accurate predictors of prostate volume than either PSA or PSA mass.

Body mass index and prostate cancer severity: do obese men harbor more aggressive disease on prostate biopsy?

OBJECTIVE

To examine the association of obesity with the prebiopsy prostate-specific antigen (PSA), Gleason score, clinical stage, and D'Amico tumor risk in 2 independent cohorts of men with prostate cancer.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of men with biopsy-proven prostate cancer from California's Improving Access, Counseling and Treatment for Californians with Prostate Cancer program and from a random sample of men treated at the University of Michigan. We performed multivariate analyses to examine the relationship of body mass index (BMI) with the prebiopsy PSA level, Gleason score, clinical stage, and D'Amico tumor risk, while controlling for demographics.

RESULTS

The mean age was 61.5 years, and the median prebiopsy PSA level was 6.7 ng/mL. Greater than 70% of men were at least overweight. On univariate analysis, the BMI was not associated with prebiopsy PSA levels, Gleason score, or D'Amico tumor risk. On multivariate analysis, we found no association between BMI and log-transformed PSA, Gleason score, clinical T stage, or D'Amico risk. Advancing age was associated with a greater risk of a higher prebiopsy PSA level, Gleason score, and D'Amico tumor risk.

CONCLUSION

Obese men with prostate cancer were no more likely to have a higher prebiopsy PSA level, Gleason score, clinical T stage, or D'Amico risk than those of normal weight. Although we do not know whether the BMI affected the prebiopsy PSA values in those without a diagnosis of prostate cancer, our findings suggest that the BMI does not affect the interpretation of the prebiopsy PSA levels in those with cancer.

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.

The impact of obesity on the predictive accuracy of PSA in men undergoing prostate biopsy

PURPOSE

Obese men have been reported to have lower serum PSA values relative to normal-weight men in population-based studies, screening cohorts, and in men with prostate cancer (CaP) treated with surgery. There are concerns that PSA may be less accurate in detecting prostate cancer in men with increased body mass index (BMI). We determine whether the diagnostic potential of PSA is negatively influenced by obesity by comparing its operating characteristics across BMI categories among men undergoing prostate biopsy.

METHODS

Demographic, clinical, and histopathological data on 917 men who underwent trans-rectal ultrasound-guided prostate needle biopsy from 2002 to 2010 at a University hospital in Italy were used in the study. Men were categorized for BMI as follows: <25 kg/m(2) (normal weight), 25-29.9 kg/m(2) (overweight), and ≥ 30 kg/m(2) (obese). Receiver operator characteristics (ROC) curves were used to assess PSA accuracy for predicting prostate cancer overall and then stratified according to digital rectal examination (DRE) findings using the area under the ROC curve (AUC).

RESULTS

The obesity rate of the study cohort was 21 %. There was no statistically significant difference in the overall AUCs of PSA for predicting CaP among normal-weight (AUC = 0.56), overweight (AUC = 0.60), and obese men (AUC = 0.60; p = 0.68) in either DRE-positive or negative men.

CONCLUSIONS

In a cohort of Italian men undergoing prostate biopsy, the performance accuracy of PSA as a predictor of CaP is not significantly altered by BMI. Obesity does not negatively impact the overall ability of PSA to discriminate between CaP and benign conditions.

Performance of prostate-specific antigen mass in estimation of prostate volume in Japanese men with benign prostate hyperplasia

OBJECTIVES

Obese men with benign prostate hyperplasia might have lower serum prostate-specific antigen because of hemodilution, resulting in underestimation of total prostate volume by serum prostate-specific antigen. The aim of this study was to compare the performance of prostate-specific antigen mass as the absolute amount of prostate-specific antigen protein secreted into circulation with that of serum prostate-specific antigen in the prediction of total prostate volume.

METHODS

A total of 1517 men with serum prostate-specific antigen up to 10 ng/mL, including 1425 with biopsy-proven benign prostate hyperplasia, were enrolled in this study. Height and weight were used to estimate body mass index, body surface area and plasma volume. Prostate-specific antigen mass was calculated as serum prostate-specific antigen multiplied by plasma volume. The association between serum prostate-specific antigen or prostate-specific antigen mass and transrectal ultrasound-measured total prostate volume were evaluated by Pearson's correlation coefficient (Υ), linear regression analyses and receiver operating characteristic curves.

RESULTS

Serum prostate-specific antigen had an inverse relationship with plasma volume, decreasing as plasma volume increased, after adjustment of total prostate volume. Larger total prostate volume per serum prostate-specific antigen was found in men with higher body mass index or plasma volume. Among all participants, the correlation (Υ = 0.456) between prostate-specific antigen mass and total prostate volume was apparently stronger than that (Υ = 0.442) between serum prostate-specific antigen and total prostate volume. Prostate-specific antigen mass outperformed serum prostate-specific antigen at estimating total prostate volume cut-off values of 30 and 40 mL. These findings were more significant in men aged ≥60 years.

CONCLUSIONS

Prostate-specific antigen mass performs better than serum prostate-specific antigen in estimating TPV, especially in men aged ≥60 years.

Effect of Roux-en-Y gastric bypass on testosterone and prostate-specific antigen

Background

Obese men have lower serum levels of testosterone, dehydroepiandrosterone (DHEA) and prostate-specific antigen (PSA), but an increased risk of dying from prostate cancer. The aim of this study was to examine the effect of surgically induced weight loss on serum testosterone, DHEA and PSA levels in obese men.

Methods

Consecutive men undergoing Roux-en-Y gastric bypass (RYGB) participated in a prospective, longitudinal study. Main outcomes were changes were body mass index (BMI), percentage excess weight loss, serum levels of testosterone, DHEA and PSA, PSA mass and plasma volume, measured before operation and 3, 6 and 12 months later.

Results

In 64 patients, mean BMI fell from 48·2 kg/m2 before operation to 39·2, 35·6 and 32·4 kg/m2 at 3, 6 and 12 months after RYGB. Testosterone levels rose significantly from 259 ng/dl to 386, 452 and 520 ng/dl respectively. Serum PSA levels increased significantly from 0·51 ng/ml to 0·67 ng/ml at 12 months. There were no significant changes in DHEA or PSA mass.

Conclusion

RYGB normalizes the serum testosterone level. PSA levels increase with weight loss and may be inversely correlated with changes in plasma volume, indicating that PSA levels may be artificially low in obese men owing to haemodilution.

Comparison of the clinical efficacy of medical treatment of symptomatic benign prostatic hyperplasia between normal and obese patients

We aimed to investigate the difference in efficacy of medical treatment of symptomatic benign prostatic hyperplasia (BPH) between normal and obese patients with BPH; obesity was determined by either body mass index (BMI) or waist circumference (WC). In this 12-week prospective observational study, a total of 175 patients aged ≥40 years with International Prostate Symptom Scores (IPSS) ≥12 points and prostate volume ≥20 ml were prospectively enrolled. The patients were divided into two groups according to BMI or WC. Patients received the doxazosin gastrointestinal therapeutic system (GITS) at a dose of 4 mg once per day for 12 weeks. The changes from baseline in the IPSS, maximal urinary flow rate (Q(max)), post-void residual volume, quality of life (QoL) scores and adverse events (AEs) were analysed. Of the 175 enrolled patients, 132 completed the study. Sixty-seven patients had BMI >23 kg m⁻², and 43 had WC >90 cm. Obese patients represented by WC >90 cm or BMI ≥23 kg m⁻² had a significantly greater prostate volume compared with non-obese patients at baseline. Total IPSS was significantly higher in the WC >90 cm group compared to the WC ≤90 cm group. Total IPSS was positively correlated with prostate volume (P=0.031) and WC (P=0.045). All groups showed significant improvements in total IPSS and QoL at 12 weeks. However, the improvement of total IPSS was greater in the high-BMI and high-WC groups. The most frequent AE was dizziness (n=13), and it was significantly lower in the obese BPH patients. Obesity was associated with increased prostate volume and lower urinary tract symptoms. Alpha-blockers appear to be efficacious for controlling symptoms, especially in obese men.

Associations between an obesity related genetic variant (FTO rs9939609) and prostate cancer risk

Observational studies suggest that obese men have a lower risk of incident prostate cancer, but an increased risk of advanced and fatal cancers. These observations could be due to confounding, detection bias, or a biological effect of obesity. Genetic studies are less susceptible to confounding than observational epidemiology and can suggest how associations between phenotypes (such as obesity) and diseases arise. To determine whether the associations between obesity and prostate cancer are causal, we conducted a genetic association study of the relationship between a single nucleotide polymorphism known to be associated with obesity (FTO rs9939609) and prostate cancer. Data are from a population-based sample of 1550 screen-detected prostate cancers, 1815 age- and general practice matched controls with unrestricted prostate specific antigen (PSA) values and 1175 low-PSA controls (PSA <0.5 ng/ml). The rs9939609 A allele, which was associated with higher BMI in the sample, was inversely associated with overall (odds ratio (OR) versus all controls  = 0.93; 95% confidence interval (CI): 0.85–1.02 p = 0.12 per allele) and low-grade (OR = 0.90; 0.81–0.99 p = 0.03 per allele) prostate cancer risk, but positively associated with high-grade cancer among cases (OR high- versus low-grade cancer  = 1.16; 0.99–1.37 p = 0.07 per allele). Although evidence for these effects was weak, they are consistent with observational data based on BMI phenotypes and suggest that the observed association between obesity and prostate cancer is not due to confounding. Further research should confirm these findings, extend them to other BMI-related genetic variants and determine whether they are due to detection bias or obesity-related hormonal changes.

Trial Registration

Controlled-Trials.com ISRCTN20141297

Association between C-peptide concentration and prostate cancer incidence in the CLUE II cohort study

Diabetes, characterized by perturbations in insulin production and signaling, is inversely associated with prostate cancer risk irrespective of stage. Obesity, a diabetes risk factor, is inversely associated with localized disease but positively associated with advanced disease. To understand the complex association between hyperinsulinemia and prostate cancer, we evaluated the association of plasma C-peptide, an insulin secretion marker, with prostate cancer risk in a case-control study nested in a prospective community cohort. Prostate cancer cases (n = 264) and matched controls (n = 264) were identified in the CLUE II cohort between 1989 (baseline) and 2002. C-peptide concentration was measured in baseline plasma by ELISA. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using conditional logistic regression, adjusting for being overweight or obese and family history. Median C-peptide concentration was lower in cases (1,180 pmol/L) than in controls (1,365 pmol/L; P = 0.03). Men in the highest (versus lowest) fourth of C-peptide had a lower risk for prostate cancer (OR, 0.65; 95% CI, 0.37-1.14; P-trend = 0.08), primarily localized disease (OR, 0.44; 95% CI, 0.19-1.03; P-trend = 0.04). Associations were similar to overall, when excluding cases diagnosed during the first 5 years of follow-up, men with diabetes, or men who had not had a prostate-specific antigen test. C-peptide concentration was inversely associated with subsequent diagnosis of prostate cancer, primarily localized disease, similar to the association for obesity. However, we cannot rule out detection bias that might result if men with higher C-peptide have lower prostate-specific antigen irrespective of whether prostate cancer is present or not.

Serum prostate-specific antigen is better correlated to body surface area than body mass index in a population of healthy Korean men

It has been suggested that the larger vascular volume among obese men causes a dilution effect, decreasing the concentration of serum prostate-specific antigen (PSA). However, plasma volume is proportional to body surface area (BSA) rather than to body mass index (BMI). We determined whether serum PSA level is better correlated to BSA than BMI in a population of ostensibly healthy Korean men. Data from 2604 men who visited our health promotion center were evaluated. All men underwent anthropometric measurements, digital rectal examination, serum PSA determination, and transrectal ultrasound examination. The correlation between serum PSA and other parameters was statistically analyzed. The mean age was 49.9 years and the mean serum PSA level was 1.14 ng/mL. The multivariate analysis revealed that the serum PSA was positively correlated with age, prostate volume, and negatively correlated with BSA only and not with BMI. In addition, BSA, rather than BMI, was the significant factor in predicting the prostate volume. Our results suggest that men with larger BSA (rather than BMI), have larger prostate volumes, and lower serum PSA.

Prostate kallikrein markers in diagnosis, risk stratification and prognosis

The kallikrein, prostate-specific antigen (PSA), is one of the world's most frequently used disease biomarkers. After almost two decades of research and clinical experience, the diagnostic and monitoring limitations of PSA are beginning to be understood. Most physicians are aware of PSA's low specificity for cancer among older men with benign prostatic conditions; fewer are aware of recent data, which show that a prior negative biopsy or a prior PSA value below the threshold for biopsy might compromise the predictive accuracy of PSA even further. Furthermore, a subtle increase in serum PSA level during early middle age is strongly correlated with clinically important prostate cancer. We review current and past reports on the prostate kallikreins PSA and hK2 in relation to pathology and epidemiology.

Obesity-PSA relationship: a new formula

To clinically apply the inverse PSA-body mass index (BMI) correlation and enhance PSA sensitivity in obese cases, a new formula is warranted. An innovated BMI-PSA equation is designed. PSA-BMI adjusted formula (named Hekal's equation): measured total PSA (ng ml(-1)) multiplied by age (years) and divided by BMI of the patient. The formula is applied over a randomly chosen 1000 cases of different PSA, BMI, age and trans-rectal ultrasound biopsy results, the yield of new PSA is correlated with pathology and age-specific PSA adjustment values. Among the 988 cases with complete data, obesity (BMI: 30-35 kg m(-2)) in 236 cases (23.8%) and 79 cases (7.9%) have BMI>35 kg m(-2). Mean PSA was 5.8 ng ml(-1) (s.d.+/-8.4 ng ml(-1)). Cases stratified based on their age (every 10 years). The new equation was applied. Obesity is detected in 33.5 and 43.6% of fifth and sixth decade of life respectively (P=0.02), with low measured PSA values (2.1, 3.8 ng ml(-1), respectively). By such PSA measurement biopsy may be omitted, missing 53.3% of malignant cases. In contrast, PSA adjusted were 4 and 9.3 ng ml(-1) within the same group of patients. With such values, the decision of a biopsy could not be missed for the targeted groups. Specificity and sensitivity of adjusted PSA values at cutoff point 4 ng ml(-1) was 41.7 and 70%, respectively. Based on our results, the new PSA-BMI adjusted formula is reproducible, easy applied formula. With such a formula the higher sensitivity of PSA in obese patients could be achieved. The misleading low PSA in obese cases in the fifth and sixth decade will be corrected.

Should prostate specific antigen be adjusted for body mass index? Data from the Baltimore Longitudinal Study of Aging

PURPOSE

Obesity may be associated with lower prostate specific antigen through hemodilution. We examined the relationship between body mass index and prostate specific antigen by age in men without prostate cancer in a longitudinal aging study to determine whether prostate specific antigen must be adjusted for body mass index.

MATERIALS AND METHODS

The study population included 994 men (4,937 observations) without prostate cancer in the Baltimore Longitudinal Study of Aging. Mixed effects models were used to examine the relationship between prostate specific antigen and body mass index in kg/m(2) by age. Separate models were explored in men with prostate cancer censored at diagnosis, for percent body fat measurements, for weight changes with time and adjusting for initial prostate size in 483 men (2,523 observations) with pelvic magnetic resonance imaging measurements.

RESULTS

In men without prostate cancer body mass index was not significantly associated with prostate specific antigen after adjusting for age (p = 0.06). A 10-point body mass index increase was associated with a prostate specific antigen difference of -0.03 ng/ml (95% CI -0.40-0.49). Results were similar when men with prostate cancer were included, when percent body fat was substituted for body mass index, and after adjusting for prostate volume. Longitudinal weight changes also had no significant association with prostate specific antigen.

CONCLUSIONS

Consistent with prior studies, we found an inverse relationship between obesity and serum prostate specific antigen. However, the magnitude of the difference was small. Thus, adjusting prostate specific antigen for body mass index does not appear warranted.

Modeling the effects of obesity and weight gain on PSA velocity

BACKGROUND

Hemodilution theory states that higher blood volume in obese men effectively dilutes circulating PSA levels resulting in lower PSA test results. Here we apply hemodilution theory to model the effect of weight gain on PSA velocity.

METHODS

Hemodilution formulas were used to model PSA velocity for a series of plausible scenarios in which initial weight and weight gain were varied. The formulas were also applied to published summary data on weight, weight change and PSA velocity from the Prostate Cancer Prevention Trial (PCPT).

RESULTS

Under hemodilution theory, PSA velocity is understood to be influenced by total circulating PSA mass (ng of PSA) and BMI at the initial test and total circulating PSA mass and BMI at the subsequent test. PSA velocity in a man with a stable BMI of 35 is estimated to be 13% lower than in a man with a stable BMI of 25. A gain of 4 BMI units is predicted to attenuate PSA velocity by as much as 25%. When applied to summary data from the PCPT, the formulas estimate that a 10 pound weight gain causes a -0.028 ng/ml change in PSA, which closely matches PCPT results where a 10 pound weight gain caused a -0.024 ng/ml change in PSA. We provide software to implement the hemodilution formulas to model PSA velocity for different weights and changes in weight through time (http://www.eheintl.com/psa.jsp).

CONCLUSION

Stable obesity and weight gain both independently attenuate PSA velocity, potentially obscuring clinically relevant changes in circulating PSA.

Effects of obesity on lower urinary tract symptoms in Korean BPH patients

We analyzed the effects of obesity on lower urinary tract symptoms (LUTSs) in Korean benign prostatic hyperplasia (BPH) patients. This is a multicenter, cross-sectional, prospective study conducted in four centers in Korea. A total of 602 men with LUTSs secondary to BPH were included. BPH/LUTSs cases were men aged >/= 40 years with international prostate symptom scores (IPSS) > or = 8 points. Height, weight and waist circumference were measured. Among the 602 patients, 156 patients had a waist circumference above 90 cm, representing central obesity, and 215 patients had a body mass index above 25 kg m(-2). Waist circumference was positively correlated with prostate volume (P = 0.034). Men with waist circumference > 90 cm experienced a 1.36-fold increased risk of severe LUTSs (95% CI 0.82-2.41) compared with men with waist circumference < or = 90 cm. Prostate volume was positively correlated with urgency and nocturia in men with central obesity. In this population of Korean men diagnosed with BPH, central obesity rather than overall obesity seems to be the more important predictor of LUTSs correlated with BPH.

Has blood volume an impact on serum PSA levels?

PURPOSE

Prostate-specific antigen (PSA) is measured in circulating blood volume (BV), which is known to have a wide inter- and intraindividual variability. As data investigating the potential impact of different BV on PSA test validity are scant, we determined the relationship between BV and serum PSA values.

METHODS

Men aged 41-60 years, participating in a health screening project, were evaluated. Serum samples of fasting patients were drawn between 8.00 and 10.00 a.m., all PSA measurements were determined in the same laboratory. Circulating BV was calculated according to the Retzlaff formula based on height, weight and haematocrit.

RESULTS

A total of 400 men with a mean age of 47.9 years entered the analysis. Mean PSA was 1.20 ng/ml (range 0.23-8.59 ng/ml) and mean BV was 3,370 ml (range 2,380-4,220 ml). Mean PSA values stratified from lowest to the highest third of BV were 1.22, 1.17 and 1.19 ng/ml in the total cohort. The respective figures for men aged 41-50 years were 1.08, 0.98 and 1.03 ng/ml, and for those aged 51-60 years: 1.47, 1.48 and 1.53 ng/ml. Neither BV nor three other related biometrical parameters (body mass index, waist-hip ratio, body fat percentage) revealed a correlation with the PSA values.

CONCLUSION

Our data suggest that BV does not have a significant impact on serum PSA values. To exclude a potential minor impact of BV on PSA, larger study cohorts, however, are required.

Effect of body mass index and waist circumference on prostate specific antigen and prostate volume in a generally healthy Korean population

PURPOSE

We examined the influences of age, body mass index and waist circumference on prostate specific antigen before and after adjusting for prostate volume. We also examined associations among age, body mass index, waist circumference and prostate volume.

MATERIALS AND METHODS

We analyzed 38,380 Korean men 30 to 79 years old who received regular checkups at our health examination center. We had prostate volume data for 3,593 of them. We divided the subjects into 5 groups by age, 4 groups by body mass index and waist circumference (using Asia-Pacific obesity reference values), and quartiles for prostate volume. We compared prostate specific antigen and prostate volume by multivariate regression analysis across body mass index and waist circumference after adjusting for age and/or prostate volume.

RESULTS

Increasing body mass index or waist circumference was associated with decreasing prostate specific antigen (with or without prostate volume adjustment) and increasing prostate volume (p for trend <0.01). When we stratified prostate volume by quartile, age was not associated with prostate specific antigen except in quartile 4 (p for trend by quartile 0.402, 0.639, 0.056 and <0.01). Mean prostate specific antigen of the group with a body mass index less than 23 in prostate volume quartile 4 was approximately 3 times that of the group with a body mass index greater than 30 in prostate volume quartile 1 (1.42 vs 0.55).

CONCLUSIONS

Obesity had a negative association with prostate specific antigen regardless of prostate volume, and a positive association with prostate volume. Age was not associated with prostate specific antigen after prostate volume adjustment. Obese men, especially those with a small prostate volume, may have lower baseline prostate specific antigen and, thus, be at higher risk for having prostate cancer undetected in a prostate specific antigen screening test.

Association of diabetes and body mass index with levels of prostate-specific antigen: implications for correction of prostate-specific antigen cutoff values?

BACKGROUND

In a recent study, an inverse association between diabetes and prostate-specific antigen (PSA) levels was observed, and several studies reported lower PSA levels in groups with higher body mass index. However, all of the studies were conducted in populations with intensive PSA screening and the role of diabetes severity, duration, and therapy are yet to be explored.

METHODS

Associations of diabetes duration and treatment, hemoglobin A1c, and BMI with PSA levels were assessed among 778 men ages 50 to 74 years, randomly chosen from the 2000 to 2002 baseline recruitment of a large population-based cohort study in Germany (prevalence of diabetes, 17%), using linear regression analyses.

RESULTS

PSA values were significantly reduced in men with insulin treatment (-39%; P = 0.006) and oral diabetic medication (-24%; P = 0.030), and in men with elevated (6.1-6.9%) and highly (> or =7%) elevated hemoglobin A1c values (-15%, P = 0.004 and -29%, P = 0.003, respectively). PSA reduction was not associated with duration of diabetes. Obesity was possibly associated with a reduction of PSA levels (-14%; P = 0.096).

CONCLUSIONS

Our study suggests that more severe forms of diabetes are associated with lower PSA levels and confirms the magnitude of reduction in PSA levels in diabetic men overall. The observed PSA reduction parallels reported risk reduction of prostate cancer among diabetic men.

Effect of population trends in body mass index on prostate cancer incidence and mortality in the United States

Concurrent with increasing prostate cancer incidence and declining prostate cancer mortality in the United States, the prevalence of obesity has been increasing steadily. Several studies have reported that obesity is associated with increased risk of high-grade prostate cancer and prostate cancer mortality, and it is thus likely that the increase in obesity has increased the burden of prostate cancer. In this study, we assess the potential effect of increasing obesity on prostate cancer incidence and mortality. We first estimate obesity-associated relative risks of low- and high-grade prostate cancer using data from the Prostate Cancer Prevention Trial. Then, using obesity prevalence data from the National Health and Nutrition Examination Survey and prostate cancer incidence data from the Surveillance, Epidemiology, and End Results program, we convert annual grade-specific prostate cancer incidence rates into incidence rates conditional on weight category. Next, we combine the conditional incidence rates with the 1980 prevalence rates for each weight category to project annual grade-specific incidence under 1980 obesity levels. We use a simulation model based on observed survival and mortality data to translate the effects of obesity trends on prostate cancer incidence into effects on disease-specific mortality. The predicted increase in obesity prevalence since 1980 increased high-grade prostate cancer incidence by 15.5% and prostate cancer mortality by between 7.0% (under identical survival for obese and nonobese cases) and 23.0% (under different survival for obese and nonobese cases) in 2002. We conclude that increasing obesity prevalence since 1980 has partially obscured declines in prostate cancer mortality.

The clinical significance in healthy men of the association between obesity related plasma hemodilution and tumor marker concentration

PURPOSE

We investigated the association between body mass index and the concentration of tumor markers including carcinoembryonic antigen, alpha-fetoprotein, the carbohydrate antigen 19-9 and prostate specific antigen, as well as the association between body mass index changes and tumor marker concentration changes in a population of healthy men.

MATERIALS AND METHODS

We evaluated data on 8,776 men screened for tumor markers (carcinoembryonic antigen, alpha-fetoprotein, carbohydrate antigen 19-9 and prostate specific antigen) at least 3 times annually during an annual examination from 2001 to 2007. We assessed the tumor marker test findings for a trend in the age, alanine aminotransferase and creatinine adjusted tumor marker concentration by body mass index. We used multivariate regression analysis to determine whether a change in body mass index was associated with a tumor marker concentration change over time using calculated tumor markers, body mass index, creatinine and alanine aminotransferase concentration change per year.

RESULTS

After adjusting for age, creatinine and alanine aminotransferase a higher body mass index was associated with lower prostate specific antigen (p for trend <0.001), carcinoembryonic antigen (p for trend <0.001) and carbohydrate antigen 19-9 (p for trend <0.001). On multivariate regression analysis each 1 kg/m(2) of body mass index gain per year was associated with a -0.011 ng/ml change in prostate specific antigen concentration, a -0.030 ng/ml change in carcinoembryonic antigen concentration and a -0.192 IU/ml change in carbohydrate antigen 19-9 concentration per year.

CONCLUSIONS

In this cohort of healthy men hemodilution from increased plasma volume may be responsible for the observed decreased tumor marker concentration in men with a higher body mass index. In addition, an increase in body mass index may predict a lower tumor marker concentration in an individual.