Association among plasma 1,25(OH)2D,ratio of 1,25(OH)2D to 25(OH)D,and prostate cancer aggressiveness |
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| Authors: | Swathi Ramakrishnan Susan E. Steck Lenore Arab Hongmei Zhang Jeannette T. Bensen Elizabeth T. H. Fontham Candace S. Johnson James L. Mohler Gary J. Smith L. Joseph Su Anna Woloszynska |
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| Affiliation: | 1. Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, New York;2. Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina;3. David Geffen School of Medicine, University of California, Los Angeles, California;4. Division of Epidemiology, Biostatistics, and Environmental Health, University of Memphis, Memphis, Tennessee;5. Department of Epidemiology, Gillings School of Global Public Health, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina;6. School of Public Health, Louisiana State University Health Sciences Center, New Orleans, Louisiana;7. Department of Urology, Roswell Park Comprehensive Cancer Center, Buffalo, New York;8. Winthrop P. Rockefeller Cancer Institute, Department of Epidemiology, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas |
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| Abstract: | Background African-American (AA) men tend to present with more aggressive prostate cancer (Gleason score >7) than European-American (EA) men. Vitamin D and its metabolites are implicated in prostate cancer biology with vitamin D deficiency, indicated by its metabolite levels in serum or plasma, usually observed in AA men. Objective To determine if 1, 25-dihydroxy vitamin D3 [1,25(OH)2D] plasma levels in AA and EA prostate cancer patients alter the risk of having aggressive prostate cancer. Design Research subjects from the North Carolina-Louisiana Prostate Cancer Project (AA n = 435 and EA n = 532) were included. Plasma metabolites 1,25(OH)2D and 25-hydroxyvitamin D3 [25(OH)D] were measured using liquid chromatography with tandem mass spectrophotometry. Research subjects were classified into low (Gleason sum < 7, stage T1-T2, and Prostate-specific antigen (PSA) < 9 ng/mL) or high (Gleason sum > 8 or Gleason sum = 7 with 4 + 3, or PSA > 20 ng/mL, or Gleason sum = 7 and stage T3-T4) aggressive disease. Results Research subjects in the second and third tertiles of plasma levels of 1, 25(OH)2D had lower odds of high aggressive prostate cancer (AA [ORT2vsT1: 0.66, 95%CI: 0.39-1.12; ORT3vsT1: 0.83, 95%CI: 0.49-1.41] and EA [ORT2vsT1: 0.68, 95%CI: 0.41-1.11; ORT3vsT1: 0.67, 95%CI: 0.40-1.11]) compared with the first tertile, though confidence intervals included the null. Greater 1,25(OH)2D/25(OH)D molar ratios were associated with lower odds of high aggressive prostate cancer more evidently in AA (ORQ4vsQ1: 0.45, CI: 0.24-0.82) than in EA (ORQ4vsQ1: 0.64, CI: 0.35-1.17) research subjects. Conclusions The 1,25(OH)2D/25(OH)D molar ratio was associated with decreased risk of high aggressive prostate cancer in AA men, and possibly in EA men. Further studies analyzing vitamin D polymorphisms, vitamin D binding protein levels, and prostatic levels of these metabolites may be useful. These studies may provide a better understanding of the vitamin D pathway and its biological role underlying health disparities in prostate cancer. |
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| Keywords: | prostate cancer racial disparities vitamin D |
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