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Blacks may not need as much Vitamin D (for their bones)


See also VitaminDwiki: Black have more health problems than whites - except for bone heatlh


The Low Blood Level of 25-Hydroxy Vitamin D in African American Women: Is It Clinically Significant?- 2016

EC Nutrition 3.2 (2016): 611-620.
Image
After vitamin D (also called cholecalciferol) is synthesized in the skin, it is metabolized to 25(OH)D (25-hydroxyvitamin D, also called calcidiol) in the liver and then to the biologically active form, 1,25(OH)2D (1,25-dihydroxyvitaminD, also called calcitriol)in the kidney. According to the guidelines of the Endocrine Society, vitamin D deficiency is defined as a blood level of 25(OH)D of 20 ng/ml or lower, and with this definition an estimated 42% to 82% of African Americans are considered vitamin D deficient. However, there is no concrete evidence of higher-than-normal rates of common disorders of vitamin D deficiency within the African American population. Our review of independent studies clearly shows that although the mean blood levels of 25(OH)D in African American women are in the deficient range, the mean blood levels of 1,25(OH)2D in African American women are unequivocally in the normal rangeand that African American women of different age groups also maintain normocalcemia (normal blood calcium level).
Furthermore, although oral supplementation of high doses of vitamin D to African American women increases their blood levels of 25(OH)D to the normal range, there is no health benefits of the supplementation when bone health is concerned.
Therefore, it appears that African American women are functionally vitamin D sufficient given that they have normal blood levels of 1,25(OH)2D, and the blood 25(OH)D level may not be the best marker of vitamin D sufficiency or deficiency in African American women. In the future, it will be critical to investigate if there are specific genetic factors that enable African American women to maintain normal blood levels of 1,25(OH)2D and bone health despite having low blood levels of 25(OH)D.

 Download the PDF from VitaminDWiki


Vitamin D Levels Have Different Effects on Atherosclerosis in Blacks and Whites, Study Finds - March 2010

http://www.sciencedaily.com/releases/2010/03/100315091259.htm

ScienceDaily (Mar. 20, 2010) — Vitamin D is quickly becoming the "go-to" remedy for treating a wide range of illnesses, from osteoporosis to atherosclerosis. However, new evidence from a Wake Forest University School of Medicine study suggests that supplementing vitamin D in those with low levels may have different effects based on patient race and, in black individuals, the supplement could actually do harm.

The study is the first to show a positive relationship between calcified plaque in large arteries, a measure of atherosclerosis or "hardening of the arteries," and circulating vitamin D levels in black patients. It appears in the March issue of the Journal of Clinical Endocrinology and Metabolism.

"In black patients, lower levels of vitamin D may not signify deficiency to the same extent as in whites," said the study's lead investigator, Barry I. Freedman, M.D., John H. Felts III Professor and chief of the section on nephrology at the School of Medicine "We should use caution when supplementing vitamin D in black patients while we investigate if we are actually worsening calcium deposition in the arteries with treatment."

Vitamin D is widely used to treat patients with osteoporosis and/or low vitamin D levels based on a medically accepted normal range. This "normal" range is typically applied to all race groups, although it was established predominantly in whites. It is thought that as low vitamin D levels rise to the normal range with supplementation, protection from bone and heart disease (atherosclerosis) may increase, as well.

Blacks generally have lower vitamin D levels than whites, partly because their darker skin pigmentation limits the amount of the vitamin produced by sunlight. Blacks also consume fewer dairy products and ingest less dietary calcium than whites, said Freedman, an affiliate of the Maya Angelou Center for Health Equity, part of the School of Medicine. Despite these lower vitamin D levels and dietary calcium ingestion, blacks naturally experience lower rates of osteoporosis and have far less calcium in their arteries. Studies further reveal that black patients with diabetes have half the rate of heart attack as whites, when provided equal access to health care. This shows that lower levels of calcified atherosclerotic plaque in blacks are associated with a lower risk of heart disease. However, blacks in the general community have higher rates of heart attack than whites, potentially due to unequal access to medical care, Freedman said.

The research team determined the relationship between circulating vitamin D levels and arterial calcium in 340 black men and women with type 2 diabetes. Calcium can deposit in blood vessel walls forming a bone-like material called "calcified atherosclerotic plaque" and this plaque can be detected by computed tomography (CT) scans. Calcified atherosclerotic plaque is a reliable predictor of risk for heart attack and stroke. The investigators measured vitamin D levels in all study participants and then performed a CT scan to detect calcium in the heart and major arteries.

"We found that higher circulating levels of vitamin D in blacks were associated with more calcium in the artery walls," Freedman said. "This is the opposite effect of what is felt to occur in white patients and shows that the accepted "normal" range of vitamin D may be different between blacks and whites.
"Many of these study patients would be placed on supplemental vitamin D by their physicians simply because their levels were felt to be in the low range." Freedman added that physicians should use caution in supplementing vitamin D levels in blacks — especially if they do not have weak bones or other reasons to take this vitamin — until the effects of supplementing vitamin D on blood vessels and heart disease are better understood.
"Doctors frequently prescribe supplemental vitamin D," Freedman said. "However, we do not know all of its effects and how they may differ between the races. The bottom line is that racial differences in calcium handling are seen and black and white patients have differing risk for bone and heart disease. We should more clearly determine the effects of supplementing vitamin D in black patients with low levels based on existing criteria and should not assume that the effects of supplementation will be the same between the races."

Co-authors of the study, which was funded by the National Institutes of Health, were Lynne E. Wagenknecht, Dr.P.H., Kristen G. Hairston, M.D., Donald W. Bowden, Ph.D., J. Jeffrey Carr, M.D., R. Caresse Hightower, Ethel J. Gordon, Jianzhao Xu, Carl D. Langefeld, Ph.D., and Jasmin Divers, Ph.D., all of the School of Medicine.
Story Source: Adapted from materials provided by Wake Forest University Baptist Medical Center.
Journal Reference:
1. Barry I. Freedman, Lynne E. Wagenknecht, Kristen G. Hairston, Donald W. Bowden, J. Jeffrey Carr, R. Caresse Hightower, Ethel J. Gordon, Jianzhao Xu, Carl D. Langefeld, and Jasmin Divers. Vitamin D, Adiposity, and Calcified Atherosclerotic Plaque in African-Americans. Journal of Clinical Endocrinology & Metabolism, 2010; 95 (3): 1076 DOI: 10.1210/jc.2009-1797

Same source as above, different reporter
March 15, 2010 http://www.physorg.com/news187850053.html

Vitamin D is quickly becoming the "go-to" remedy for treating a wide range of illnesses, from osteoporosis to atherosclerosis. However, new evidence from a Wake Forest University School of Medicine study suggests that supplementing vitamin D in those with low levels may have different effects based on patient race and, in black individuals, the supplement could actually do harm.

The study is the first to show a positive relationship between calcified plaque in large arteries, a measure of atherosclerosis or "hardening of the arteries," and circulating vitamin D levels in black patients. It appears in the March issue of the Journal of Clinical Endocrinology and Metabolism.

"In black patients, lower levels of vitamin D may not signify deficiency to the same extent as in whites," said the study's lead investigator, Barry I. Freedman, M.D., John H. Felts III Professor and chief of the section on nephrology at the School of Medicine "We should use caution when supplementing vitamin D in black patients while we investigate if we are actually worsening calcium deposition in the arteries with treatment."

Vitamin D is widely used to treat patients with osteoporosis and/or low vitamin D levels based on a medically accepted normal range. This "normal" range is typically applied to all race groups, although it was established predominantly in whites. It is thought that as low vitamin D levels rise to the normal range with supplementation, protection from bone and heart disease (atherosclerosis) may increase, as well.

Blacks generally have lower vitamin D levels than whites, partly because their darker skin pigmentation limits the amount of the vitamin produced by sunlight. Blacks also consume fewer dairy products and ingest less dietary calcium than whites, said Freedman, an affiliate of the Maya Angelou Center for Health Equity, part of the School of Medicine. Despite these lower vitamin D levels and dietary calcium ingestion, blacks naturally experience lower rates of osteoporosis and have far less calcium in their arteries. Studies further reveal that black patients with diabetes have half the rate of heart attack as whites, when provided equal access to health care. This shows that lower levels of calcified atherosclerotic plaque in blacks are associated with a lower risk of heart disease. However, blacks in the general community have higher rates of heart attack than whites, potentially due to unequal access to medical care, Freedman said.

The research team determined the relationship between circulating vitamin D levels and arterial calcium in 340 black men and women with type 2 diabetes. Calcium can deposit in blood vessel walls forming a bone-like material called "calcified atherosclerotic plaque" and this plaque can be detected by computed tomography (CT) scans. Calcified atherosclerotic plaque is a reliable predictor of risk for heart attack and stroke. The investigators measured vitamin D levels in all study participants and then performed a CT scan to detect calcium in the heart and major arteries.

"We found that higher circulating levels of vitamin D in blacks were associated with more calcium in the artery walls," Freedman said. "This is the opposite effect of what is felt to occur in white patients and shows that the accepted "normal" range of vitamin D may be different between blacks and whites.

"Many of these study patients would be placed on supplemental vitamin D by their physicians simply because their levels were felt to be in the low range." Freedman added that physicians should use caution in supplementing vitamin D levels in blacks - especially if they do not have weak bones or other reasons to take this vitamin - until the effects of supplementing vitamin D on blood vessels and heart disease are better understood.

"Doctors frequently prescribe supplemental vitamin D," Freedman said. "However, we do not know all of its effects and how they may differ between the races. The bottom line is that racial differences in calcium handling are seen and black and white patients have differing risk for bone and heart disease. We should more clearly determine the effects of supplementing vitamin D in black patients with low levels based on existing criteria and should not assume that the effects of supplementation will be the same between the races."

Provided by Wake Forest University Baptist Medical Center (news : web)


Vitamin D production after UVB exposure depends on baseline vitamin D and total cholesterol but not on skin pigmentation.- 2010

J Invest Dermatol. 2010 Feb;130(2):546-53. Epub 2009 Oct 8.
Bogh MK, Schmedes AV, Philipsen PA, Thieden E, Wulf HC.
Department of Dermatology, Copenhagen University Hospital, Bispebjerg, Copenhagen NV Vejle, Denmark. bogh at dadlnet.dk

UVB radiation increases serum vitamin D level expressed as 25-hydroxyvitamin-D(3) (25(OH)D), but the influence of skin pigmentation, baseline 25(OH)D level, and total cholesterol has not been well characterized. To determine the importance of skin pigmentation, baseline 25(OH)D level, and total cholesterol on 25(OH)D production after UVB exposure, 182 persons were screened for 25(OH)D level. A total of 50 participants with a wide range in baseline 25(OH)D levels were selected to define the importance of baseline 25(OH)D level.

Of these, 28 non-sun worshippers with limited past sun exposure were used to investigate the influence of skin pigmentation and baseline total cholesterol. The participants had 24% of their skin exposed to UVB (3 standard erythema doses) four times every second or third day. Skin pigmentation and 25(OH)D levels were measured before and after the irradiations. Total cholesterol was measured at baseline.

The increase in 25(OH)D level after UVB exposure was negatively correlated with baseline 25(OH)D level (P<0.001) and positively correlated with baseline total cholesterol level (P=0.005), but no significant correlations were found with constitutive or facultative skin pigmentation. In addition, we paired a dark-skinned group with a fair-skinned group according to baseline 25(OH)D levels and found no differences in 25(OH)D increase after identical UVB exposure. PMID: 19812604

Lower cholesterol ==> lower potential for vitamin D creation


The 25(OH)D/PTH Threshold in Black Women - 2010

J Clin Endocrinol Metab. 2010 Aug 4.
Aloia JF, Chen DG, Chen H.
Bone Mineral Research Center, Winthrop-University Hospital, Mineola, New York 11501.

Context: Black women have lower 25-hydroxyvitamin D 25(OH)D and higher PTH than white women. Recent evidence implicates PTH in adverse cardiovascular outcomes.
Objective: The objective of the study was to determine whether PTH increases at lower 25(OH)D levels (the threshold) in black compared with white women.

Design: Healthy black and white women, aged 20-80 yr were recruited to participate in a cross-sectional study of body-composition in black and white women. Measurement of serum 25(OH)D and PTH were carried out. Setting: The study was a convenience sample recruited from a community setting. Patients: Healthy black and white women were recruited by advertising and a direct mail campaign in a comparative study of body composition. Age ranged from 20-to 80 yr. There were 148 black and 129 white premenopausal participants and 87 black and 139 white postmenopausal participants.

Main Outcome: The main outcome was to determine whether the threshold for 25(OH)D/PTH differs in black and white women.
Results: A threshold of 37 nmol/liter (95% confidence interval 35-40) was found for black and 59 nmol/liter (95% confidence interval 56-63) for white women.
These two values were significantly different (P < 0.001).

Conclusions: Black women have an increase in serum PTH at a lower 25(OH)D level than white women.
Negative health outcomes of higher PTH should be investigated in black women. PMID: 20685862

CLICK HERE for entire report
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Comment: It has been assumed that when vitamin D exceeds a minimum threshold then the level of PTH increases.
If that assumption is correct, then black women need less vitamin D in their blood than do white women.


Twice as much rise Vit D in blood from milk and multivitamin for African-Americans in LA Mar 2010

Contributions of food intake to serum 25 OH vitamin D levels in healthy African American and Caucasian Los Angelinos
Lenore Arab1, Casey Nelson2, Mary Catherine Cambou2, Heeyoung Kim3, Ronald Horst4, Katherine Wessling-Perry2 and Patricia Jardack2
FASEB (Societies of Experimental Biology) March 2010
1 General Internal Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
2 David Geffen School of Medicine at UCLA, Los Angeles, CA
3 School of Public Health at UCLA, Los Angeles, CA
4 Heartland Assays, Ames, IA

To determine the impact of diet on circulating levels of vitamin D we studied healthy, weight constant African Americans and Caucasians in Los Angeles. We examined the relative contributions of dietary intakes from fish, dairy and multivitamin supplements from 6 24-hour recalls. Distinct racial differences were noted, with a median of 21.2 ng/ml for African Americans, and 34.4 for Caucasians. Multiple linear regression models, adjusted for age and gender were run to examine the relationship between serum vitamin D levels and dietary consumption of vitamin D-rich foods. Across the total population, dairy consumption was strongly related to 25 OH vitamin D levels, with the contributions from full fat and non-fat milk demonstrating statistically significant regression coefficients of 1.45 and 1.78, respectively.

The elevation in vitamin D seen per 100 g full fat milk consumption was also almost twice as great among the African American subjects (2.0 vs 1.1 ng/ml elevation per 100 g). Fish consumption was not significantly related to circulating levels in this population.

Use of a multivitamin had almost twice the impact among the African Americans (11.6 vs 6.3 ng/ml elevation per tablet).
The lack of association with fish and the differential effects of diet in African Americans deserves further attention. Supported by NIH R01CA105048.


Vitamin D levels of blacks > 20 ng is sufficient for bone health - July 2018

Screening for Vitamin D Deficiency in Black Americans: Comparison of Total, Free, Bioavailable 25 Hydroxy Vitamin D Levels with Parathyroid Hormone Levels and Bone Mineral Density
The journal of nutrition, health & aging, pp 1–6 DOI https://doi.org/10.1007/s12603-018-1080-y
Alexis McKee Email author S. M. Lima RibeiroT. K. MalmstromH. M. PerryIIID. K. MillerS. S. FarrM. L. NiehoffS. G. Albert

Objectives: There is debate surrounding the adequacy of total and free 25 hydroxy vitamin D 25(OH)D levels in black Americans who have inherently high bone mineral density [BMD] and low serum concentration of vitamin D binding proteins VDBP.

Design: Retrospective analysis of serum samples and BMD analyses from the African American Health Study AAHS cohort.

Setting: The AAHS is a population-based longitudinal study initiated to examine issues of disability and frailty among urban-dwelling black Americans in the city of Saint Louis, Missouri.

Participants: 122 men and 206 women, age 60.2 ± 4.3 years.

Intervention: Retrospective analysis.

Measurements: Total 25(OH)D, VDBP, PTH, and BMD of the lumbar spine and hip by dual energy x-ray photometry (DXA). Free and bioavailable vitamin D levels were calculated using serum concentrations and affinity constants for the VDBP (Gc1F and Gc1S) phenotypes.

Results
Serum total 25(OH) D levels were 14.6 ± 8.9 ng/mL (36 ± 22 nmol/L). Vitamin D insufficiency was estimated by compensatory elevations of PTH above the normal range (> 65 pg/mL). PTH levels were within the normal reference range in > 95% of the samples at total 25(OH)D levels ≥ 20 ng/mL (≥50 nmol/L). There was no difference in the correlation of the reciprocal relationship of vitamin D vs parathyroid hormone between the VDBP phenotypes. Receiver operating characteristic curve analyses indicated that serum total 25(OH)D discriminated sufficiency from insufficiency at least as well as the calculated levels of the free and bioavailable vitamin D. Very low levels of total 25(OH)D (≤ 8 ng/mL, ≤20 nmol/L) were associated with decreased BMD (p=0.02), but higher levels of 25(OH)D did not show statistical differences in BMD.

Conclusion
Total 25(OH)D levels of ≤ 8ng/mL (≤20 nmol/L) are associated with clinically significant changes in BMD, whereas total 25(OH)D levels ≥ 20 ng/mL (≥50 nmol/L) suppressed PTH and were not associated with deficiencies in BMD. Lower levels of 25(OH)D may be acceptable for bone health in black than in white Americans.

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