Serum 25‐hydroxyvitamin D, vitamin D binding protein, and prostate cancer risk in black men

Abstract

BACKGROUND Few studies have prospectively examined the relationship between vitamin D status and prostate cancer risk in black men, a group at high risk for both low vitamin D status and prostate cancer. METHODS Among black men in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, we identified 226 prostate cancer cases and 452 controls matched on age at randomization (±5 years), date of blood draw (±30 days), calendar year of cohort entry, and time since baseline prostate cancer screening (±1 year). Conditional logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between serum 25-hydroxyvitamin D [25(OH)D], vitamin D binding protein (DBP), the 25(OH)D:DBP molar ratio, and prostate cancer risk. RESULTS Serum 25(OH)D was not associated with overall prostate cancer (Q4 vs Q1: OR, 0.73; 95% CI, 0.40–1.33; P for trend = .25), although there were apparent inverse associations for nonaggressive disease (global P = .03, clinical stage I/II, and Gleason score <7) and among men ≥62 years old (P for interaction = .04) that were restricted to Q3. Interestingly, serum DBP was significantly inversely associated with prostate cancer risk (Q4 vs Q1: OR, 0.45; 95% CI, 0.20–1.00; P for trend = .03), whereas the 25(OH)D:DBP molar ratio was not. Results were similar when we mutually adjusted for 25(OH)D and DBP, and we found no evidence of interaction between the two. CONCLUSION Our study suggests higher (versus lower) circulating DBP may be independently associated with a decreased prostate cancer risk in black men independent of 25(OH)D status.

The association of serum vitamin D–binding protein and 25‐hydroxyvitamin D in pre‐operative and post‐operative colorectal cancer

“…Several studies have reported that serum VDBP was associated with prostate, pancreatic, bladder cancer, and acute leukemia . As mentioned above, several studies found that there was no association between VDBP and CRC .…”

“…Moreover, VDBP is the precursor to the Gc protein–derived macrophage‐activating factor (Gc‐MAF) that can activate macrophages against cancer cell . Recently, several studies have reported that serum VDBP was associated with prostate, pancreatic, and bladder cancers as well as acute leukemia . Several papers have pointed that VDBP was not associated with CRC .…”

Association among plasma 1,25(OH)2D, ratio of 1,25(OH)2D to 25(OH)D, and prostate cancer aggressiveness

“…Vitamin D binding protein sequesters free circulating 1,25(OH) 2 D that is required to activate VDR. A recent study suggested that the risk of aggressive prostate cancer in AA men inversely correlated with vitamin D binding protein rather than 25(OH)D levels . Therefore, investigating the levels of vitamin D binding protein in the context of supplementation and serum/prostate metabolite levels may provide a more accurate picture of this pathway in prostate cancer and its role in racial disparities .…”

“…Most studies in prostate cancer measure vitamin D sufficient or deficient status in individuals by measuring 25(OH)D levels in the serum and not necessarily the active 1,25(OH) 2 D metabolite . Our previous study showed that research subjects with the highest percentage of African ancestry had the lowest levels of 25(OH)D .…”

“…AA men are more likely to be diagnosed with and/or die from aggressive prostate cancer than EA men . Differences in vitamin D metabolite levels have been suggested to play a role in prostate cancer disparities between AA and EA men . 1,25(OH) 2 D negatively regulates CDK2 or induces Rb1 that result in cell cycle arrest in the G1 phase, to reduce prostate cancer cell proliferation in vitro.…”