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.

Oxidised low-density lipoprotein, a possible distinguishing lipid profile biomolecule between prostate cancer and benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) and prostate cancer (PCa) share common conditions such as lower urinary tract symptoms (LUTS) and dyslipidaemia. Whether an extensive lipid profile analysis could discriminate between BPH and PCa was the objective. Thirty-six (36) BPH and twenty (20) PCa outpatients of a urology clinic plus forty (40) controls without LUTS, but normal PSA, were recruited. Body mass index (BMI), lipid profile (total cholesterol [CHOL], triglycerides [TG], high-density lipoprotein [HDL], very-low-density lipoprotein [VLDL], low-density lipoprotein [LDL] and Castelli's risk index I [CR I] [TC/HDL]), oxidised LDL, apolipoprotein E, ceramide and PSA were determined. Mean ages for BPH, PCa and control were 69 ± 13, 67 ± 10 and 53 ± 7 years respectively. Most parameters apart from BMI and HDL were significantly different compared to the control group. oxLDL for BPH versus control, PCa versus control and BPH versus PCa was significant (p < 0.001, p = 0.02 and p < 0.001 respectively). Ceramide showed significant group differences. Between BPH and PCa, total cholesterol, LDL and Apo E were significantly different (p = 0.00, p = 0.01 and p = 0.03 respectively). Apo E could potentially be a discriminating biomarker. Receiver operating characteristic curves for TPSA, Apo E and oxLDL demonstrated sensitivity of 69.44 and specificity of 88.24 for oxLDL, hence more discriminatory.

Age-specific Serum Prostate Specific Antigen Ranges Among Apparently Healthy Nigerian Men Without Clinical Evidence of Prostate Cancer

INTRODUCTION

Serum prostate specific antigen (PSA) levels increase with age and varies among different races and communities. The study was aimed at defining the age-specific reference ranges of serum PSA in our environment.

METHODS

We evaluated the relationship between age and serum PSA levels and the age-specific reference ranges of serum PSA among civil servants in Lagos, who underwent routine medical checkups. Criteria for inclusion were men who have no lower urinary tract symptoms, normal digital rectal examination and serum PSA ≤ 20 ng/ml. SPSS Statistic 21 was used for data evaluation and the mean, median, 95(th) percentile PSA levels were estimated. Pearson's correlation was used to examine the relationship, and P < 0.05 was considered significant.

RESULTS

4032 men met the criteria for inclusion in the evaluation. The mean age was 51.6 (range 40-70) years, and there was a strong correlation between serum PSA levels and age (r = 0.097, P < 0.001). PSA ranges of 0-2.5, >2.5-4.0, >4.0-10, and >10 ng/ml were found in 3218 (80%), 481 (12%), 284 (7%), and 52 (1%) men, respectively. The mean, median and the 95(th) percentile PSA for the overall group were 1.84, 1.33, and 5.2 ng/ml respectively. However the 95(th) percentile PSA levels for men aged 40-49, 50-59, and 60-70 years were 4.78, 5.47, and 8.93 ng/ml respectively.

CONCLUSION

The age-specific PSA levels among Nigerian men for each age group is higher than what was described for men in the Western world. These reference ranges of serum PSA should be considered for men aged ≥40 years in our environment.

Obesity and prostate cancer incidence and mortality: a systematic review of prospective cohort studies

BACKGROUND

There has been a large body of research on obesity and the risk of prostate cancer (PCa) that has been published recently. However, the epidemiological evidence for such an association has not been consistent. This may be attributed to the nature of case-control and retrospective studies, which generally are more prone to biases. Therefore, we conducted a systematic review of prospective cohort studies to assess the association between obesity and the risk of PCa incidence and death.

METHODS

A search of the PubMed database and references of published studies (from inception until March 2013) was conducted. Twenty-three eligible studies were identified and included in the systematic review.

RESULTS

The evidence from the prospective cohort studies linking obesity with PCa incidence has not been consistent. However, cumulative data is compelling for a strong positive association between obesity and fatal PCa.

CONCLUSIONS

Obesity is a significant diet-related risk factor for fatal PCa. Further well-constructed, large cohort studies on the potential association between obesity and PCa, as well as on underlying mechanisms, are needed.

Association of prostate specific antigen concentration with lifestyle characteristics in Korean men

We investigated the relationships between demographics, lifestyle characteristics, and serum total prostate specific antigen (PSA) concentration and examined the population-based distribution of total PSA by age among 2,246 Korean men with a median age of 45 years. We obtained data about demographic and lifestyle characteristics based on self-reporting using a questionnaire. We also performed physical examinations, anthropometric measurements, and biochemical measurements. The PSA concentration increased with age and there was a significant difference in total PSA concentration between the age groups of 21-60 years and >60 years. Age>60 years, height≥1.8 m, a low frequency of alcohol consumption, and taking nutritional supplements showed a significantly increased odds ratio for increased PSA when 3.0 ng/ mL was chosen as the PSA cut-off level. Smoking status, BMI, percent body fat, diabetes mellitus, fatty liver, herbal medicine use, vitamin use, and diet were not significantly associated with total PSA regardless of the cut-off level. When interpreting a single PSA test, height, alcohol consumption, and nutritional supplement use should be considered, in addition to age.