The association of metabolic syndrome and its components with serum prostate-specific antigen levels

Exposure to heavy metal elements may significantly increase serum prostate-specific antigen levels with overdosed dietary zinc

BACKGROUND

Serum prostate-specific antigen (PSA) is a primary metric for diagnosis and prognosis of prostate cancer (PCa). Exposure to heavy metals, such as lead, cadmium, mercury, and zinc can impact PSA levels in PCa patients. However, it is unclear whether this effect also occurs in men without PCa, which may lead to the overdiagnosis of PCa.

METHOD

Data on a total of 5089 American men who had never been diagnosed with PCa were obtained from the National Health and Nutrition Examination Survey performed from 2003-2010. The relationship between serum PSA levels (dependent variable) and concentrations of lead (μmol/L), cadmium (nmol/L), and mercury (μmol/L) were investigated with dietary zinc intake being used as a potential modifier or covariate in a weighted linear regression model and a generalized additive model. A series of bootstrapping analyses were performed to evaluate sensitivity and specificity using these models.

RESULTS

Regression analyses suggested that, in general, lead, cadmium, or mercury did not show an association with PSA levels, which was consistent with the results of the bootstrapping analyses. However, in a subgroup of participants with a high level of dietary zinc intake (≥14.12 mg/day), a significant positive association between cadmium and serum PSA was identified (1.06, 95% CI, P = 0.0268, P for interaction=0.0249).

CONCLUSIONS

With high-level zinc intake, serum PSA levels may rise in PCa-free men as the exposure to cadmium increases, leading to a potential risk of an overdiagnosis of PCa and unnecessary treatment. Therefore, environmental variables should be factored in the current diagnostic model for PCa that is solely based on PSA measurements. Different criteria for PSA screening are necessary based on geographical variables. Further investigations are needed to uncover the biological and biochemical relationship between zinc, cadmium, and serum PSA levels to more precisely diagnose PCa.

Association of TyG index with prostate-specific antigen (PSA) in American men: results from NHANES, 2003-2010

BACKGROUND

In recent years, triglyceride-glucose index (TyG) was a new indicator of insulin resistance, and it has been widely reported that it may be associated with serum prostate-specific antigen (PSA) concentrations.

AIMS

We intended to investigate the possible connection between serum PSA concentration and the TyG index.

METHODS

This is a cross-sectional study of adults with complete data on TyG and serum PSA concentrations (ng/ml) from the NHANES, 2003-2010. The TyG index is obtained by the formula below: TyG = Ln [triglycerides (mg/dL) × fasting glucose(mg/dL)/2]. Multivariate regression analysis and subgroup analysis were used to examine the connection between the TyG index and serum PSA levels.

RESULTS

Multiple regression analysis of the weighted linear model showed that individuals with a higher TyG index had lower PSA levels. Subgroup analyses and interaction tests showed no apparent dependence on age, race/ethnicity, BMI, household income ratio, education level, and marital status on this negative association (all interactions p > 0.05).

CONCLUSIONS

TyG index is related to lower serum PSA concentrations in adult men from the USA. Further comprehensive prospective studies are needed to confirm our findings.

Total Prostate Specific Antigen in Prostate Cancer Screening in Hyperglycemic Individuals

AIM

In this study, it was aimed to investigate the reliability of total prostate-specific antigen (t-PSA) in prostate cancer screening in hyperglycemic (≥126 mg/dL) individuals.

METHODS

This research was planned as a cross-sectional retrospective study. Three hundred eleven cases which underwent biopsy with the suspicion of prostate cancer in the hospital were included in the study. Prostate cancer risk groups were categorized as low, intermediate and high. Those with fasting blood glucose (FBG) levels lower than 126 mg/dL were considered as the normoglycemia group.

RESULTS

It was determined that the t-PSA measurement was higher in the patient group with cancer (P < .001). It was determined that the median t-PSA levels of the intermediate and high cancer groups were higher than the low cancer group (P < .001 and P = .001, respectively). t-PSA was found to be associated with increased cancer risk in cases with FBG <126. However, an increase in t-PSA values in cases with FBG ≥126 was not associated with increased prostate cancer. There is no relationship between FBG measurement and t-PSA measurement (rs=0.05, P = .446). In addition, it was determined that the t-PSA measurements of patients with FBG ≥126 and FBG<126 did not differ (P = .962).

CONCLUSIONS

As a contribution to literature, we found that the t-PSA test lost its sensitivity in cases with plasma glucose levels above normal. Loss of sensitivity may result in underdiagnosis in prostate cancer and this, in turn, results in diagnosis of the cancer at a later stage. In the future, it may be necessary to adopt a different approach in prostate cancer screening in hyperglycemic cases.

Metabolic syndrome biomarkers and prostate cancer risk in the UK Biobank

We investigated the association between metabolic syndrome (MetS) and its components and risk of prostate cancer (PCa) in a cohort of men enrolled in the UK Biobank. Our study cohort included 220 622 PCa-free men with baseline measurements of triglycerides (TGs), HDL-cholesterol (HDL), glycated hemoglobin (HbA1c), blood pressure (BP), and waist circumference (WC). Multivariable Cox proportional hazards regression was used to analyze associations with PCa for: individual metabolic components (TG, HDL, HbA1c, BP, WC), combinations of two and three components, and MetS overall (three or more components). We conducted mediation analyses to examine potential hormonal and inflammatory pathways (total testosterone [TT], C-reactive protein [CRP], insulin-like growth factor 1 [IGF-1]) through which MetS components may influence PCa risk. A total of 5409 men in the study developed PCa during a median follow-up of 6.9 years. We found no significant association between MetS and PCa risk (hazard ratio [HR] = 0.99, 95% confidence interval [CI] = 0.92-1.06). No associations were found with PCa risk and individual measurements of TG, HDL, BP, or WC. However, an inverse association was observed with elevated HbA1c (≥42 mmol/mol) (HR = 0.89, 95% CI = 0.79-0.98). Consistent inverse associations were observed between HbA1c and risk of PCa. Mediation analysis revealed TT, CRP, and IGF-1 as potential mediating factors for this association contributing 10.2%, 7.1%, and 7.9% to the total effect, respectively. Overall MetS had no association with PCa risk. However, a consistent inverse association with PCa risk was found for HbA1c. This association may be explained in part through hormonal and inflammatory pathways.

Clinical factors affecting prostate-specific antigen levels in prostate cancer patients undergoing radical prostatectomy: a retrospective study

Background:

Since prostate-specific antigen (PSA) levels can be influenced by some routinely available clinical factors, a retrospective study was conducted to explore the influence of obesity, smoking habit, heavy drinking and chronic obstructive pulmonary disease on PSA levels in men with histologically confirmed prostate cancer.

Patients & methods:

We reviewed the medical records of 833 prostate cancer patients undergoing radical prostatectomy.

Results:

Serum PSA levels at the time of surgery were not associated with either BMI or history of chronic obstructive pulmonary disease or heavy drinking. Conversely, PSA levels were associated with smoking status.

Conclusion:

Among the clinical factors explored in this homogeneous population, only tobacco use was associated with PSA levels, which should be considered when using PSA-based screening in male smokers.

Smokers with prostate cancer tend to show higher PSA levels at the time of radical prostatectomy. As higher PSA levels are associated with a worse prognosis, smoking habit may have a prognostic value in prostate cancer. Further studies are required to explore the underlying biology of this finding.