Inverse relationship between obesity and serum prostate-specific antigen level in healthy Japanese men: a hospital-based cross-sectional survey, 2004-2006

Obesity and prostate cancer screening, incidence, and mortality in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

BACKGROUND

Though obesity, measured by body mass index (BMI), is an established risk factor for several cancer sites, there is conflicting evidence on whether obesity increases prostate cancer risk or mortality and, if it does, whether it increases risk directly or indirectly by affecting prostate cancer screening efficacy.

METHODS

We examined associations between BMI and prostate cancer screening outcomes, incidence, and mortality in men randomly assigned to the intervention arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (n = 36 756) between 1993 and 2001. Participants received annual screening with the prostate-specific antigen test and digital rectal exam. Associations between baseline BMI and screening outcomes were assessed via multinomial logistic regression, and associations with prostate cancer incidence and mortality were assessed via Cox proportional hazards regression.

RESULTS

Individuals with higher BMI were less likely to screen positive via the prostate-specific antigen test and/or digital rectal exam and more likely to have an inadequate screen (all Ptrend < .01). Higher BMI was inversely associated with prostate cancer incidence (per 5 kg/m2 BMI increase: hazard ratio [HR] = 0.94, 95% confidence interval [CI] = 0.91 to 0.97), including incidence of early stage (HR = 0.94, 95% CI = 0.90 to 0.97) and advanced-stage (HR = 0.91, 95% CI = 0.82 to 1.02) disease, but positively associated with prostate cancer mortality (HR = 1.21, 95% CI = 1.06 to 1.37). The association with mortality was not modified by screening outcome (Pinteraction = .13).

CONCLUSIONS

Within this screened population, individuals with higher BMI had lower risk of prostate cancer diagnosis but higher risk of prostate cancer mortality. As higher BMI was not positively associated with advanced-stage prostate cancer risk, the increased mortality is unlikely to be due to delayed prostate cancer detection.

Systematic review and meta-analysis of the associations between body mass index, prostate cancer, advanced prostate cancer, and prostate-specific antigen

PURPOSE

The relationship between body mass index (BMI) and prostate cancer remains unclear. However, there is an inverse association between BMI and prostate-specific antigen (PSA), used for prostate cancer screening. We conducted this review to estimate the associations between BMI and (1) prostate cancer, (2) advanced prostate cancer, and (3) PSA.

METHODS

We searched PubMed and Embase for studies until 02 October 2017 and obtained individual participant data from four studies. In total, 78 studies were identified for the association between BMI and prostate cancer, 21 for BMI and advanced prostate cancer, and 35 for BMI and PSA. We performed random-effects meta-analysis of linear associations of log-PSA and prostate cancer with BMI and, to examine potential non-linearity, of associations between categories of BMI and each outcome.

RESULTS

In the meta-analyses with continuous BMI, a 5 kg/m2 increase in BMI was associated with a percentage change in PSA of - 5.88% (95% CI - 6.87 to - 4.87). Using BMI categories, compared to normal weight men the PSA levels of overweight men were 3.43% lower (95% CI - 5.57 to - 1.23), and obese men were 12.9% lower (95% CI - 15.2 to - 10.7). Prostate cancer and advanced prostate cancer analyses showed little or no evidence associations.

CONCLUSION

There is little or no evidence of an association between BMI and risk of prostate cancer or advanced prostate cancer, and strong evidence of an inverse and non-linear association between BMI and PSA. The association between BMI and prostate cancer is likely biased if missed diagnoses are not considered.

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.

Low body mass index is associated with adverse oncological outcomes following radical prostatectomy in Korean prostate cancer patients

PURPOSE

The purpose of this study was to determine the impact of obesity on clinicopathological features and biochemical recurrence (BCR) following radical prostatectomy (RP) in Korean prostate cancer (PCa) patients.

METHODS

A single-institutional retrospective analysis was performed on 880 PCa patients treated by RP without neoadjuvant therapy between July 2005 and December 2011. Patients were stratified according to body mass index (BMI) standards for Asian populations: obese (BMI ≥25 kg/m(2)), overweight (BMI 23-24.9 kg/m(2)), or normal weight (BMI <23 kg/m(2)). For analysis, overweight and obese patients were combined (n = 592, BMI ≥23 kg/m(2)) and compared with normal weight patients (n = 288, BMI <23 kg/m(2)). BCR was defined as prostate-specific antigen (PSA) ≥0.2 ng/ml following RP.

RESULTS

Normal weight patients tended to be classified into the higher D'Amico risk category with smaller prostate volumes compared with obese and overweight patients. Normal weight patients had higher pathological Gleason scores and were at higher risk of BCR during the mean follow-up of 58.2 months. This translated to a higher 5-year BCR-free survival rate for obese and overweight patients compared with normal weight patients (77.8 vs. 70.3 %; p = 0.017). On multiple Cox-proportional hazards regression analysis incorporating variables of BMI category, PSA, positive surgical margins, pathological T stage, and Gleason score, higher BMI category remained a significant predictor of a lower risk of BCR (HR = 0.634, p = 0.028).

CONCLUSIONS

Obese and overweight Korean PCa patients have lower Gleason scores and a reduced risk of BCR compared with normal weight patients. These findings suggest that body fat influences pathological features and oncologic outcomes of PCa.

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.

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.

A novel equation and nomogram including body weight for estimating prostate volumes in men with biopsy-proven benign prostatic hyperplasia

Anthropometric measurements, e.g., body weight (BW), body mass index (BMI), as well as serum prostate-specific antigen (PSA) and percent-free PSA (%fPSA) have been shown to have positive correlations with total prostate volume (TPV). We developed an equation and nomogram for estimating TPV, incorporating these predictors in men with benign prostatic hyperplasia (BPH). A total of 1852 men, including 1113 at Tokyo Medical and Dental University (TMDU) Hospital as a training set and 739 at Cancer Institute Hospital (CIH) as a validation set, with PSA levels of up to 20 ng ml(-1), who underwent extended prostate biopsy and were proved to have BPH, were enrolled in this study. We developed an equation for continuously coded TPV and a logistic regression-based nomogram for estimating a TPV greater than 40 ml. Predictive accuracy and performance characteristics were assessed using an area under the receiver operating characteristics curve (AUC) and calibration plots. The final linear regression model indicated age, PSA, %fPSA and BW as independent predictors of continuously coded TPV. For predictions in the training set, the multiple correlation coefficient was increased from 0.38 for PSA alone to 0.60 in the final model. We developed a novel nomogram incorporating age, PSA, %fPSA and BW for estimating TPV greater than 40 ml. External validation confirmed its predictive accuracy, with AUC value of 0.764. Calibration plots showed good agreement between predicted probability and observed proportion. In conclusion, TPV can be easily estimated using these four independent predictors.

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.

Associations of whole-blood fatty acids and dietary intakes with prostate cancer in Jamaica

OBJECTIVE

To investigate the association of whole-blood fatty acids and reported intakes of fats with risk of prostate cancer (PCa).

DESIGN

Case-control study of 209 men 40-80 years old with newly diagnosed, histologically confirmed prostate cancer and 226 cancer-free men attending the same urology clinics. Whole-blood fatty acid composition (mol%) was measured by gas chromatography and diet assessed by food frequency questionnaire.

RESULTS

High whole-blood oleic acid composition (tertile 3 vs. tertile 1: OR, 0.37; CI, 0.14-0.0.98) and moderate palmitic acid proportions (tertile 2: OR, 0.29; CI, 0.12-0.70) (tertile 3: OR, 0.53; CI, 0.19-1.54) were inversely related to risk of PCa, whereas men with high linolenic acid proportions were at increased likelihood of PCa (tertile 3 vs. tertile 1: OR, 2.06; 1.29-3.27). Blood myristic, stearic and palmitoleic acids were not associated with PCa. Higher intakes of dietary MUFA were inversely related to prostate cancer (tertile 3 vs. tertile 1: OR, 0.39; CI 0.16-0.92). The principal source of dietary MUFA was avocado intake. Dietary intakes of other fats were not associated with PCa.

CONCLUSIONS

Whole-blood and dietary MUFA reduced the risk of prostate cancer. The association may be related to avocado intakes. High blood linolenic acid was directly related to prostate cancer. These associations warrant further investigation.

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.

Relationship between changes in haemoglobin A1C and prostate-specific antigen in healthy men

BACKGROUND

Although many studies have shown an inverse relationship between diabetes and prostate cancer, it still remains unclear why diabetes may reduce the risk of prostate cancer. An inverse association between haemoglobin A(1C) (HbA(1C)) and prostate-specific antigen (PSA) also has been reported in previous studies that assessed the association cross-sectionally. To fully understand the relationship between diabetes and prostate cancer, it is essential to examine the association in a longitudinal design. The effect of plasma volume should also be considered in examining the PSA level. The aim of this study was to determine whether changes in HbA(1C) were associated with PSA levels, independent of plasma volume changes, as indicated by haematocrit and weight.

METHODS

We investigated 5917 Japanese men aged 50 and over who visited St. Luke's International Hospital, Tokyo for routine health check-ups in 2006 and 2007. We performed a multiple linear regression analysis to examine any association between changes in HbA(1C) and PSA over 1 year.

RESULTS

Adjusting for age, body mass index at baseline and changes in weight and haematocrit, the increases in HbA(1C) and PSA were concordant (5.7% increase per 1-unit HbA(1C) change; 95% confidence interval, 2.8-8.5%; p<0.001).

CONCLUSIONS

In contrast to previous cross-sectional observations showing an inverse association between HbA(1C) and PSA, longitudinal observations suggest a positive association between the two. Further studies are needed to investigate the association between diabetes and prostate cancer.

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.