Body mass index influences prostate-specific antigen in men younger than 60 years of age

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.

Age, height, BMI and FBG predict prostate volume in ageing benign prostatic hyperplasia: Evidence from 5285 patients

AIMS

Several studies have reported a potential association between prostate volume (PV) and prostate disease. Here, we classified the risk factors for PV among benign prostatic hyperplasia (BPH) patients.

METHODS

In all, 4293 BPH patients with available clinical information were enrolled. Body mass index (BMI) was obtained as weight divided by height squared. PV was calculated as length × width × height (cm) × π/6. Mann-Whitney U tests were used to determine the differences between PV subgroups. Univariate and multiple linear regression tests were performed to uncover the connection between clinical features and PV. The differences in the age, BMI, height and fasting blood glucose (FBG) of the subgroups were evaluated by Kruskal-Wallis tests and adjusted with Bonferroni post hoc correction. A nomogram was created to directly illustrate the mutual interaction of amalgamator parameters.

RESULTS

PV did not influence the incidence of kidney stones (P = .815), whereas prostate calculi were positively associated with an enlarged prostate (>30 mL) (P < .001). Age (adjusted R = 0.363, P < .001), height (adjusted R = 0.088, P < .001), BMI (adjusted R = 0.039, P = .013) and FBG (adjusted R = -0.034, P = .027) were the independent risk/protective factors related to enlarged PV among BPH patients. The nomogram illustrated the predictive risk of an enlarged prostate (>30 mL) in men. The area under the ROC curve value was 0.659 in the training cohort and 0.677 in an internal validation cohort.

CONCLUSIONS

Age, height and BMI were positive independent risk factors of enlarged PV in BPH patients, and FBG had a protective role.

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.

Prostate-specific antigen lowering effect of metabolic syndrome is influenced by prostate volume

OBJECTIVES

To investigate the influence of metabolic syndrome on prostate-specific antigen levels by considering prostate volume and plasma volume.

METHODS

We retrospectively analyzed 4111 men who underwent routine check-ups including prostate-specific antigen and transrectal ultrasonography. The definition of metabolic syndrome was based on the modified Adult Treatment Panel III criteria. Prostate-specific antigen mass density (prostate-specific antigen × plasma volume / prostate volume) was calculated for adjusting plasma volume and prostate volume. We compared prostate-specific antigen and prostate-specific antigen mass density levels of participants with metabolic syndrome (metabolic syndrome group, n = 1242) and without metabolic syndrome (non-prostate-specific antigen metabolic syndrome group, n = 2869). To evaluate the impact of metabolic syndrome on prostate-specific antigen, linear regression analysis for the natural logarithm of prostate-specific antigen was used.

RESULTS

Patients in the metabolic syndrome group had significantly older age (P < 0.001), larger prostate volume (P < 0.001), higher plasma volume (P < 0.001) and lower mean serum prostate-specific antigen (non-metabolic syndrome group vs metabolic syndrome group; 1.22 ± 0.91 vs 1.15 ± 0.76 ng/mL, P = 0.006). Prostate-specific antigen mass density in the metabolic syndrome group was still significantly lower than that in the metabolic syndrome group (0.124 ± 0.084 vs 0.115 ± 0.071 μg/mL, P = 0.001). After adjusting for age, prostate volume and plasma volume using linear regression model, the presence of metabolic syndrome was a significant independent factor for lower prostate-specific antigen (prostate-specific antigen decrease by 4.1%, P = 0.046).

CONCLUSIONS

Prostate-specific antigen levels in patients with metabolic syndrome seem to be lower, and this finding might be affected by the prostate volume.

The likelihood of having serum level of PSA of ≥4.0 ng/mL and ≥10.0 ng/mL in non-obese and obese Nigerian men with LUTS

Objective

This study was undertaken to determine the likelihood of having serum total prostate specific antigen (PSA) levels ≥4.0 ng/mL and ≥10.0 ng/mL among a cohort of non-obese and obese Nigerian men with lower urinary tract symptoms (LUTS).

Methods

This was a prospective cross-sectional survey among men who presented with benign prostatic hypertrophy to the urology clinic of the Ekiti State University Teaching Hospital, Ado -Ekiti with LUTS between January 1 and December 31, 2014. One hundred and forty men who presented in the urologic clinic with LUTS were recruited. PSA was analyzed using standard method while other clinical variables were collected using a clinical case form. Multivariate logistic regression was used to estimate the odds of an abnormal PSA of ≥4.0 ng/mL or ≥10.0 ng/mL in these men.

Results

The mean ages of obese and non-obese men were 64.8 and 64.0 years respectively. The mean total serum PSA were 14.8 and 13.2 ng/mL for obese and non-obese men respectively. Univariate analysis showed no difference (p > 0.05) in the proportion of obese and non-obese men with LUTS who had a PSA threshold of at least 4.0 ng/mL. Multivariate logistic regression showed that, at a PSA threshold of 10.0 ng/mL, obese men had a statistically significant proportion (p < 0.05). Although not significant, non-obese patients were less likely to have PSA level of ≥4.0 ng/mL (OR 0.701; 95% CI 0.301–1.630) compared to obese men. In the same vein, non-obese men were less likely to have a PSA level of 10.0 ng/mL (OR, 0.686; 95% CI, 0.318–1.478) in a simultaneous context of age.

Conclusion

Our study demonstrated that, in a sample population of predominantly native African men, there was a non-significantly higher likelihood of overweight/obese patients having a higher serum PSA level than the non-obese. A community based study is needed to further confirm this finding.

Higher body mass index increases the risk for biopsy-mediated detection of prostate cancer in Chinese men

Objective

To investigate the relationship between body mass index (BMI) and prostate cancer (PCa) risk at biopsy in Chinese men.

Patients and Methods

We retrospectively reviewed the records of 1,807 consecutive men who underwent initial multicore (≥10) prostate biopsy under transrectal ultrasound guidance between Dec 2004 and Feb 2014. BMI was categorised based on the Asian classification of obesity as follows: <18.5 (underweight), 18.5–22.9 (normal weight), 23–24.9 (overweight), 25–29.9 (moderately obese), and ≥30 kg/m2 (severely obese). The odds ratios (OR) of each BMI category for risk of PCa and high-grade prostate cancer (HGPCa, Gleason score ≥4+3) detection were estimated in crude, age-adjusted and multivariate-adjusted models. Prevalence ratios and accuracies of PSA predicted PCa were also estimated across BMI groups.

Results

In total, PCa was detected by biopsy in 750 (45.4%) men, and HGPCa was detected in 419 (25.4%) men. Compared with men of normal weight, underweight men and obese men were older and had higher prostate specific antigen levels. The risk of overall PCa detection via biopsy presented an obvious U-shaped relationship with BMI in crude analysis. Overall, 50.0%, 37.4%, 45.6% 54.4% and 74.1% of the men in the underweight, normal weight, overweight, moderately obese and severely obese groups, respectively, were diagnosed with PCa via biopsy. In multivariate analysis, obesity was significantly correlated with a higher risk of PCa detection (OR = 1.17, 95%CI 1.10–1.25, P<0.001). However, higher BMI was not correlated with HGPCa detection (OR = 1.03, 95%CI 0.97–1.09, P = 0.29). There were no significant differences in the accuracy of using PSA to predict PCa or HGPCa detection across different BMI categories.

Conclusion

Obesity was associated with higher risk of PCa detection in the present Chinese biopsy population. No significant association was detected between obesity and HGPCa.

Obesity affects the biopsy-mediated detection of prostate cancer, particularly high-grade prostate cancer: a dose-response meta-analysis of 29,464 patients

BACKGROUND AND OBJECTIVES

In previous studies, obesity (measured according to the body mass index) has correlated inconsistently with the risk of biopsy-measured prostate cancer, and specifically high-grade prostate cancer. This meta-analysis aimed to clarify these correlations.

METHODS

A comprehensive literature search of the MEDLINE and EMBASE databases was conducted for relevant studies published through January 2014. The pooled estimates of odds ratios (OR) and confidence intervals (CI) were computed, and the meta-analysis was performed with the STATA software according to a random effects approach.

RESULTS

A total of 11 studies that included 29,464 individuals were identified. A 5-kg/m2 increase in body mass index was associated with a 15% (OR, 1.15; 95% CI, 0.98-1.34) higher risk of prostate cancer detection and a 37% (OR, 1.37; 95% CI, 1.19-1.57) higher risk of high-grade prostate cancer detection at biopsy. There were no differences among the results of studies conducted in the USA, Europe or Asia. We also found that studies that had adjusted for prostate-specific antigen levels, digital rectal examination results, and prostate volumes obtained positive significant outcomes (OR, 1.27; 95% CI, 1.12-1.44), whereas studies that did not adjust for the above-mentioned confounding variables obtained negative results (OR, 0.92; 95% CI, 0.68-1.25). Moreover, the positive correlation between body mass index and the detection of both prostate cancer and high-grade diseases tended to be stronger as the number of biopsy cores increased.

CONCLUSION

The present meta-analysis demonstrated that a high body mass index correlated positively with prostate cancer detection, especially high-grade prostate cancer detection. The adoption of a modified and possibly more aggressive biopsy strategy was suggested for obese populations.

Influence of opioid consumption on serum prostate-specific antigen levels in men without clinical evidence of prostate cancer

OBJECTIVE

To determine the effect of opioid consumption on the serum prostate-specific antigen (PSA) level.

METHODS

From April 2009 to December 2011, 56 opioid users and 82 age-matched controls participated in the present study. The exclusion criteria were prostate cancer or other malignancies, serum PSA level ≥ 4 ng/dL, abnormal digital rectal examination findings, previous prostate surgery, pelvic radiotherapy, bladder stone, urinary tract infection, recent prostatic manipulation, and a history of taking drugs that alter the serum PSA level. The prostate volume and PSA, serum testosterone, and luteinizing and follicle-stimulating hormone levels were measured in the eligible participants and compared between the opioid users and control subjects. The study was conducted in accordance with the Declaration of Helsinki, and the institutional review board approved the study.

RESULTS

The serum PSA level was significantly lower in opioid users compared with that in the control subjects (0.82 ± 0.77 vs 1.95 ± 1.00, P < .001). The testosterone level was also lower in the opioid users (339.08 ± 142.49 vs 396.71 ± 133.64, P = .008). The difference between the PSA levels remained significant when a comparison was performed between the eugonadal opioid users and eugonadal control subjects. Moreover, the effect of opioid consumption on the PSA level persisted on multivariate analysis, controlling for serum testosterone level.

CONCLUSION

Opium consumption was associated with significant decline in the serum PSA level and warrants adjustment in the PSA cutpoints at which biopsy is recommended. Opioid-induced hypogonadism does not seem to account for the PSA decline, and additional studies are required to determine the involved mechanisms.

Trends and co-trends of prostate-specific antigen and body mass index in a screened population

OBJECTIVES

This report investigated whether annual changes in body mass index (BMI) are associated with the opposite changes in prostate-specific antigen (PSA). Previous studies have confirmed lower PSA levels among men with higher BMI.

METHODS

Normal linear mixed models were used to characterize annual PSA, BMI and the ratio of PSA to BMI profiles for 2641 men undergoing prostate cancer screening for up to 8 years as part of a San Antonio screening study.

RESULTS

Among the 1898 participants (71.9%) who never received a prostate biopsy during the study and the 585 participants (22.1%) who had one or more biopsies, all negative for prostate cancer, BMI was higher for Hispanics than other racial groups, lower for older men at study entry, and increased every year during the study; and PSA and PSA/BMI ratios were higher for older men at study entry and increased each year on study (all P values<.05). Among the 158 men (6.0%) eventually diagnosed with prostate cancer, no trends in BMI were statistically significant, but PSA and PSA/BMI ratios were higher on average for older men at study entry and increased each year on study (both P values<.05). Correlations between BMI and PSA changes per year were negative but not statistically significantly different from zero.

CONCLUSIONS

The individual man scrutinizing his PSA and weight year to year can expect a slight annual increase in both, but changes in PSA from one year to the next cannot be attributed to weight gain or loss.

Body mass index and serum lipid profile influence serum prostate-specific antigen in Chinese men younger than 50 years of age

This study is to assess the potential factors that could affect the serum prostate-specific antigen (PSA) level in healthy younger men. We evaluated the associations of age, body mass index (BMI) and serum lipid profile with serum PSA level in 6774 Chinese men (aged 20-49 years) who received a routine health examination. Eligible men were classified into 10-year age groups. BMI was categorized as underweight (<18.5), normal (18.5-22.9), overweight (23.0-24.9), obese (25.0-29.9) and very obese (>30) according to the redefined World Health Organization (WHO) criteria for the Asia-Pacific region. PSA levels were compared among groups as well. In multiple linear regression analysis, PSA was positively correlated with age (P<0.0001). Negative correlations existed between PSA and BMI (P<0.0001) and triglyceride level (P=0.01). No relationship could be found between PSA and serum cholesterol (P=0.711) or high-density lipoprotein (HDL; P =0.665). In addition, we found that serum PSA levels increased with age and decreased with BMI. Our study demonstrates that age, BMI and triglyceride levels influence the PSA level in men <50 years of age.

Body mass index adjusted prostate-specific antigen and its application for prostate cancer screening

OBJECTIVES

The prostate cancer prevention trial (PCPT) prostate cancer risk calculator was developed to aid physicians in counseling men for consideration of prostate biopsy based on prostate-specific antigen (PSA) and other clinical risk factors. This study investigated the role of body mass index (BMI) in this assessment.

MATERIALS AND METHODS

BMI category was defined as < 25 (under/normal weight), 25.0-29.9 (overweight), 30.0-34.9 (obese [OB] I), 35.0-39.9 (OB II), and ≥ 40 (OB III). BMI-adjusted PSA for a man was determined by multiplying his PSA to the ratio of the geometrical mean of PSA for BMI < 25 to the geometrical mean of PSA for his BMI category. Operating characteristics of PSA and BMI-adjusted PSA were compared with PCPT risks using area underneath the receiver operating characteristic curve (AUC). Statistical tests of differences between AUCs for different diagnostic tests were performed with the nonparametric U-statistic method.

RESULTS

BMI-adjusted PSA equaled to unadjusted PSA multiplying 1.09, 1.20, 1.50, and 1.71 for men in overweight, OBI, OBII, and OBIII categories, respectively. The AUC for BMI-adjusted PSA values (0.84) did not differ from PSA; that of the PCPT calculator with BMI-adjusted PSA (0.87) did not differ from the calculator with PSA. Of 2816 men with a PSA less than or equal to 2.5 ng/mL who did not undergo biopsy, 126 (4.5%) would have a BMI-adjusted PSA exceeding 2.5 ng/mL.

CONCLUSIONS

Because of lower levels of PSA, overweight and obese men may have diminished cancer detection opportunities when undergoing PSA-based screening.

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.

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.