Vit. d and increased heart disease risk




This study is a good illustration of the minimal, optimal, and maximal
process in biology. The min. for some effect to appear, the opt. for best
benefit and max. where adding more does no good and can become toxic. The
threshold between opt. and max. for vit d and heart disease is described.

<http://www.medpagetoday.com/Cardiology/Prevention/30514>

Low levels of vitamin D may confer a cardiovascular benefit, but too much
vitamin D may have the opposite effect, according to a large
cross-sectional
study.

The critical threshold appears to be a serum 25-hydroxyvitamin D
concentration of

*****21 ng/mL ******

more than that level increases C-reactive protein (CRP), a biomarker for
cardiovascular disease, but lower serum concentrations of 25-hydroxyvitamin
D lower CRP levels, reported Muhammad Amer, MD, and Rehan Qayyum, MD, MHS,
from Johns Hopkins University School of Medicine. Their findings were
published online in the American Journal of Cardiology.

A multivariate analysis that tracked 25-hydroxyvitamin D concentrations as
well as CRP in more than 15,000 healthy adults revealed that above the
threshold for benefit, CRP increased with each 10-ng/mL increase in
25-hydroxyvitamin D.

In a univariate analysis, CRP levels decreased as levels of
25-hydroxyvitamin D increased up to the median of 21 ng/mL.

The authors analyzed data from participants in the National Health and
Nutrition Examination Survey (NHANES). Researchers combined three two-year
cycles of continuous NHANES surveys from 2001 to 2006.

The mean age of participants was 46, and the median serum 25-hydroxyvitamin
D and CRP levels were 21 ng/mL and 0.21 mg/dL, respectively. The proportion
of men to women was close, 48% versus 52%, with no significant difference
in
levels of 25-hydroxyvitamin D between the two groups.

Whites had significantly higher baseline levels of 25-hydroxyvitamin D than
nonwhites.

Significantly more people with a body mass index greater than 30 kg/m2 had
lower 25-hydroxyvitamin D levels at baseline (41% versus 25%, P<0.0001);
the
same was true for smokers (22% versus 18%, P=0.004).




Relation between serum 25-hydroxyvitamin D and C-reactive protein in
asymptomatic adults (from the Continuous National Health and Nutrition
Examination Survey 2001 to 2006

Am J Cardiol 2012; 109: 226-230.
.