Association between Plasma 25-Hydroxyvitamin D, Ancestry and Aggressive Prostate Cancer among African Americans and European Americans in PCaP.
BACKGROUND
African Americans (AAs) have lower circulating 25-hydroxyvitamin D3 [25(OH)D3] concentrations and higher prostate cancer (CaP) aggressiveness than other racial/ethnic groups. The purpose of the current study was to examine the relationship between plasma 25(OH)D3, African ancestry and CaP aggressiveness among AAs and European Americans (EAs).


METHODS
Plasma 25(OH)D3 was measured using LC-MS/MS (Liquid Chromatography Tandem Mass Spectrometry) in 537 AA and 663 EA newly-diagnosed CaP patients from the North Carolina-Louisiana Prostate Cancer Project (PCaP) classified as having either 'high' or 'low' aggressive disease based on clinical stage, Gleason grade and prostate specific antigen at diagnosis. Mean plasma 25(OH)D3 concentrations were compared by proportion of African ancestry. Logistic regression was used to calculate multivariable adjusted odds ratios (OR) and 95% confidence intervals (95%CI) for high aggressive CaP by tertile of plasma 25(OH)D3.


RESULTS
AAs with highest percent African ancestry (>95%) had the lowest mean plasma 25(OH)D3 concentrations. Overall, plasma 25(OH)D3 was associated positively with aggressiveness among AA men, an association that was modified by calcium intake (ORT 3vs.T1: 2.23, 95%CI: 1.26-3.95 among men with low calcium intake, and ORT 3vs.T1: 0.19, 95%CI: 0.05-0.70 among men with high calcium intake). Among EAs, the point estimates of the ORs were <1.0 for the upper tertiles with CIs that included the null.


CONCLUSIONS
Among AAs, plasma 25(OH)D3 was associated positively with CaP aggressiveness among men with low calcium intake and inversely among men with high calcium intake. The clinical significance of circulating concentrations of 25(OH)D3 and interactions with calcium intake in the AA population warrants further study.
Department of Epidemiology and Biostatistics, Center for Research in Nutrition and Health Disparities, Cancer Prevention and Control Program, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina, United States of America.
Susan E
SE
Steck
David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America.
Lenore
L
Arab
University of Memphis, Memphis, Tennessee, United States of America.
Hongmei
H
Zhang
Department of Epidemiology, Gillings School of Global Public Health, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.
Jeannette T
JT
Bensen
School of Public Health, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America.
Elizabeth T H
ET
Fontham
Roswell Park Cancer Institute, Buffalo, New York, United States of America.
Candace S
CS
Johnson
Roswell Park Cancer Institute, Buffalo, New York, United States of America.
James L
JL
Mohler
Roswell Park Cancer Institute, Buffalo, New York, United States of America.
Gary J
GJ
Smith
Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, Maryland, United States of America.
Joseph L
JL
Su
Roswell Park Cancer Institute, Buffalo, New York, United States of America.
Donald L
DL
Trump
Roswell Park Cancer Institute, Buffalo, New York, United States of America.
Anna
A
Woloszynska-Read
D001741:Black or African American; D003710:Demography; D004032:Diet; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness; D016017:Odds Ratio; D010802:Phylogeny; D011471:Prostatic Neoplasms / Q000097:blood* / Q000208:ethnology / Q000473:pathology*; D014481:United States; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D044465:White People
D014807:Vitamin D; C104450:25-hydroxyvitamin D