Hormonal Vitamin D & PCa Aggressiveness.

[pjoshea13]

New study below [1].

Hormonal vitamin D is calcitriol, 1,25-D, 1, 25-dihydroxy vitamin D3 [1,25(OH)2 D].

The inactive reservoir form is calcidiol, 25-D, 25-hydroxyvitamin D3 [25(OH)D].

Circulating calcitriol varies throughout the day in response to blood calcium levels. One would need to take multiple readings to discover the trend.

"Research subjects in the second and third tertiles of plasma levels of {calcitriol} had {a third less chance} of high aggressive prostate cancer" compaired to the first.

"Greater {calcitriol:calcidiol} ratios were associated with lower odds of high aggressive prostate cancer". 55% less for African Americans; 36% less for European Americans.

Note that in my vitamin D posts, I point out that a good calcidiol level (the normal blood test) is not enough. Calcitriol is the active form. In PCa, cells have lost the ability to convert calcidiol to calcitriol. Calcium, phosphorus & phosphates can inhibit calcitriol production, whereas fructose can promote it.

A single calcitriol blood test does not reveal much about calcitriol levels throughout the day, on an average day. However, with enough tests over time, one can categorize someone as a low, average or high producer, with some degree of certainty.

-Patrick

[1] ncbi.nlm.nih.gov/pubmed/310...

Prostate. 2019 May 11. doi: 10.1002/pros.23824. [Epub ahead of print]

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

Ramakrishnan S1, Steck SE2, Arab L3, Zhang H4, Bensen JT5, Fontham ETH6, Johnson CS1, Mohler JL7, Smith GJ7, Su LJ8, Woloszynska A1.

Author information

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)2 D] 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)2 D 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)2 D 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)2 D/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)2 D/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.

© 2019 The Authors. The Prostate Published by Wiley Periodicals, Inc.

KEYWORDS:

prostate cancer; racial disparities; vitamin D

PMID: 31077420 DOI: 10.1002/pros.23824

[pjoshea13]

Nala,

The half-life of Calcitriol, the active hormonal form of vitamin D is indeed ~15 hours, and the half life of calcidiol (the inactive reservoir) is ~15 days.

-Patrick

medscape.com/viewarticle/73...

[herb1]

First, readers must be careful to note the difference between calciDIOL and calciTRIOL. Second, the real trick may be getting a doctor (and insurance company) who will be willing to authorize and pay for repeated Vit D tests.

[pjoshea13 in reply to herb1]

When I first asked my GP for a test, many years ago, he hadn't done that before. He noticed that there were two test, so ordered both. If he had asked, I would have said: "NOT the one that has "1," in the description - calcitriol. But now I think it would be nice to always get both.

-Patrick

[CantChoose]

It's a chicken-and-egg problem though. Vit D is low in the first place because the typical conversion of dietary and environmental Vit D isn't happening in liver and immune cells. Dumping more into the system doesn't necessarily result in that conversion, and measuring the uptake just tells you how your immune system is responding to the cancer. It's not actionable.