Difference in Association of Obesity With Prostate Cancer Risk Between US African American and Non-Hispanic White Men in the Selenium and Vitamin E Cancer Prevention Trial (SELECT)

Abstract

IMPORTANCE African American men have the highest rates of prostate cancer incidence and mortality in the United States. Understanding underlying reasons for this disparity could identify preventive interventions important to African American men. OBJECTIVE To determine whether the association of obesity with prostate cancer risk differs between African American and non-Hispanic white men and whether obesity modifies the excess risk associated with African American race. DESIGN, SETTING, AND PARTICIPANTS Prospective study of 3398 African American and 22 673 non-Hispanic white men who participated in the Selenium and Vitamin E Cancer Prevention Trial (2001–2011) with present analyses completed in 2014. MAIN OUTCOMES AND MEASURES Total, low-grade (Gleason score <7), and high-grade (Gleason score ≥7) prostate cancer incidence. RESULTS With a median (interquartile range) follow-up of 5.6 (1.8) years, there were 270, 148, and 88 cases of total, low-, and high-grade prostate cancers among African American men and a corresponding 1453, 898, and 441 cases in non-Hispanic white men, respectively. Although not associated with risk among non-Hispanic white men, BMI was positively associated with an increase in risk among African American men (BMI, <25 vs ≥35: hazard ratio [HR], 1.49 [95% CI, 0.95, 2.34]; P for trend = .03). Consequently, the risk associated with African American race increased from 28% (HR, 1.28 [95% CI, 0.91–1.80]) among men with BMI less than 25 to 103% (HR, 2.03 [95% CI, 1.38–2.98]) among African American men with BMI at least 35 (P for trend = .03). Body mass index was inversely associated with low-grade prostate cancer risk within non-Hispanic white men (BMI, <25 vs ≥35: HR, 0.80 [95% CI, 0.58–1.09]; P for trend = .02) but positively associated with risk within African American men (BMI, <25 vs ≥35: HR, 2.22 [95% CI, 1.17–4.21]; P for trend = .05). Body mass index was positively associated with risk of high-grade prostate cancer in both non-Hispanic white men (BMI, <25 vs ≥35: HR, 1.33 [95% CI, 0.90–1.97]; P for trend = .01) and African American men, although the increase may be larger within African American men, albeit the racial interaction was not statistically significant (BMI, <25 vs ≥35: HR, 1.81 [95% CI, 0.79–4.11]; P for trend = .02). CONCLUSIONS AND RELEVANCE Obesity is more strongly associated with increased prostate cancer risk among African American than non-Hispanic white men and reducing obesity among African American men could reduce the racial disparity in cancer incidence. Additional research is needed to elucidate the mechanisms underlying the differential effects of obesity in African American and non-Hispanic white men.

Obesity and Prostate Cancer: A Focused Update on Active Surveillance, Race, and Molecular Subtyping

“…The paper that suggested the obesity-prostate cancer link may vary by race was a post hoc analysis of the Selenium and Vitamin E Cancer Prevention (SELECT) trial, which included 26 071 men (3398 black men) [11]. Consistent with many prior studies as reviewed in our previous review [1], the authors found that among white men, obesity was positively associated with high-grade disease (hazard ratio [HR] 1.33, 95% confidence interval [CI] 0.90–1.97; p = 0.01 for trend) but inversely associated with low-grade prostate cancer (HR 0.80, 95% CI 0.58–1.09; p = 0.02 for trend).…”

“…However, among black men, obesity was positively associated with both low-grade (HR 2.22, 95%CI 1.17–4.21; p = 0.05 for trend) and high-grade disease (HR 1.81, 95% CI 0.79–4.11; p = 0.02 for trend). Moreover, although obesity was associated with high-grade disease in both white and black men, the association was much stronger in black (81% higher risk) than in white men (33% higher risk) [11]. These data are supported by an analysis of the National Health and Nutrition Examination Surveys (NHANES), which included 3152 men without prostate cancer (625 black men) and used elevated PSA (>4 ng/ml) as an endpoint for assessing prostate cancer risk.…”

Fatores De Risco Para O Câncer De Próstata: População De Uma Unidade Básica De Saúde

“…Acredita-se também que a obesidade é um fator de risco para o CaP tanto como o fator genético e ambiental (18) .…”

“…Entretanto, a assistência à saúde, principalmente no serviço público, carece de melhorias estruturais e de acesso, para que o diagnóstico e consequentemente o tratamento para essa doença sejam realizados adequadamente e em tempo hábil (18) . Um estudo americano sugeriu que a distância física percorrida até a unidade de saúde com acesso a consulta com urologista pode ser uma barreira para o diagnóstico precoce do CaP (24) .…”

Contribution of Adipose Tissue to Development of Cancer

“…Additionally, in patients with confirmed breast cancers, obesity is associated with increased risk of breast cancer invasion (143, 272), development of distant metastases (111, 247, 294), tumor recurrence (42, 346), and mortality (2, 24, 55, 64, 84, 229, 420, 436) irrespective of molecular subtype. On the other hand, the role of obesity in risk of prostate cancer development remains equivocal (22, 32, 48, 283), in part because, similar to breast cancer, prostate cancer risk in obese individuals also appears to vary by race (32, 127). However, in confirmed prostate cancers, obesity is consistently associated with an elevated risk of cancer aggression (high Gleason scoring, a grading system used to inform the prognosis of men with prostate cancer) and prostate cancer-associated mortality (206, 463).…”