The association of body mass index and prostate‐specific antigen in a population‐based study

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 À1 ) 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 À2 ) in 236 cases (23.8%) and 79 cases (7.9%) have BMI435 kg m À2 . Mean PSA was 5.8 ng ml À1 (s.d.±8.4 ng ml À1 ). 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 ¼ 0.02), with low measured PSA values (2.1, 3.8 ng ml À1 , 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 À1 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 À1 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.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Obesity–PSA relationship: a new formula

Hekal

Ibrahiem

2009

“…16,17,23 Studies investigating the effects of BMI among men with elevated PSA consistent with biopsy referral have not shown a clear relationship. 9 Overall, the association between body size and PSA density appears to be attributable to the relationships between body size and prostate volume.…”

Section: Discussionmentioning

confidence: 99%

“…Increased prostate-specific antigen (PSA) testing 14,15 and somewhat lower blood PSA levels associated with BMI, 16,17 and differential prostate cancer detection with respect to obesity as mediated by effects on prostate volume may also contribute to inconsistencies in research investigating the association between obesity and prostate cancer risk.…”

Section: Introductionmentioning

confidence: 99%

The association between body size, prostate volume and prostate-specific antigen

Fowke

Motley

Cookson

et al. 2006

Increasing prostate volume contributes to urinary tract symptoms and may obscure prostate cancer detection. We investigated the association between obesity and prostate volume, prostate-specific antigen (PSA) and PSA density among 753 men referred for prostate biopsy. Among men with a negative biopsy, prostate volume significantly increased approximately 25% from the lowest to highest body mass index (BMI), waist or hip circumference or height categories. PSA was 0.7 ng/ml lower with a high waist-to-hip ratio. These associations were less consistent among subjects diagnosed with high-grade prostatic intraepithelial neoplasia or cancer. Our data suggest that obesity and height are independently associated with prostate volume.

“…2 Among the many factors that may affect blood PSA levels, such as age and race, BMI has been associated with lower PSA levels among apparently healthy men without a history of prostate cancer. [35][36][37] Indeed, PSA expression is under androgen receptor regulation, and obesity and hyperinsulinemia are also associated with lower testosterone levels. [38][39][40][41][42] However, a prior study found no association between leptin or adiponectin and PSA among prostate cancer patients, 43,44 and the component(s) of body adiposity as estimated by BMI that affect PSA levels and perhaps the ability to detect early-stage prostate cancer remain unclear.…”

Section: Introductionmentioning

confidence: 99%

Association between prostate-specific antigen and leptin, adiponectin, HbA1c or C-peptide among African-American and Caucasian men

Fowke

Matthews

Buchowski

et al. 2007

Prior studies report slightly lower prostate-specific antigen (PSA) levels among obese men. To understand this effect, we investigated the association between PSA and blood HbA1c, C-peptide, leptin and adiponectin levels in African-American (AA) (n ¼ 121) and Caucasian (CA) (n ¼ 121) men. Among AA men, PSA levels decreased with increasing C-peptide levels (PSA ¼ 0.99, 0.93, 0.75 and 0.53 ng ml À1 across quartiles of C-peptide, respectively; P trend ¼ 0.005). Among CA men, PSA levels decreased with increasing HbA1c (PSA ¼ 0.84, 0.73, 0.77 and 0.45 ng ml À1 across quartiles of HbA1c, respectively; P trend ¼ 0.005). This may suggest that metabolic disturbances related to metabolic syndrome or diabetes affect the ability to detect early-stage prostate cancer.