High Vitamin D Supplementation May Be Needed for Women in Middle East

High Vitamin D Supplementation May Be Needed for Women in Middle East

High Vitamin D Supplementation May Be Needed
for Women in Middle East
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This following piece suggests to me
that people should expose more skin the just
their face and arms to the sun.

And further, I wonder if people bath too much? Hence
reducing amount of vitamin D synthesis?

I'll also suggest what many think of as effective
sun exposure isn't. Too late in the day for example.
Or while in the car.....how much good does that do??

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* w w w .medscape . com /viewarticle/559103




Vitamin D Level May Be Low Despite Adequate Sun Exposure CME/CE

News Author: Will Boggs
CME Author: Hien T. Nghiem, MD
Disclosures
Release Date: June 29, 2007; Valid for credit through June 29, 2008




June 29, 2007

In many individuals, vitamin D level can
remain low despite abundant sun exposure, according to a
report in the June issue of The Journal of Clinical
Endocrinology & Metabolism.

Inadequate sun exposure is often blamed for the high
prevalence of low vitamin D status, the authors explain,
but the truth of this has been unclear.

Dr. Neil Binkley with the University of Wisconsin
Osteoporosis Clinical Research Program, Madison, and
colleagues investigated the vitamin D status of people
living in Hawaii with high amounts of sun exposure.

The 93 participants in the study spent an average 22.4
hours per week outside without sunscreen and 28.9 hours
per week outside with and without sunscreen, the authors report.

This translates to a mean of 11.1 hours per week of total
body skin exposure with no sunscreen used, the results indicate.

Despite this abundant sun exposure, 51% of the subjects
had serum 25-hydroxyvitamin D concentrations below 30 ng/mL,
defined as "low vitamin D status," the researchers report.
The highest observed level was 62 ng/mL.

"This implies that the common clinical recommendation to
allow sun exposure to the hands and face for 15 minutes
may not ensure vitamin D sufficiency," the investigators say.

Overall, vitamin D level did not correlate with age,
skin color, or sun exposure, the report indicates.
However, participants in the lowest vitamin D quartile
compared to the rest of the participants had higher
parathyroid hormone levels and lower sun exposure scores.

"Clinicians should not assume that individuals with
abundant sun exposure have adequate vitamin D status,"
the authors conclude.

They recommend that in treating vitamin D deficiency
with vitamin D supplementation, "it seems prudent" to
aim for a serum 25-hydroxyvitamin D concentration
no greater than the maximum produced by natural UV
exposure; i.e., approximately 60 ng/mL (150 nmol/L).

J Clin Endocrinol Metab. 2007;92:2130-2135.

Reuters Health Information 2007. © 2007 Reuters Ltd.
Clinical Context

Lack of sun exposure is widely accepted as the primary
cause of epidemic low vitamin D status worldwide. It may
not only contribute to the development of osteoporosis and
osteomalacia/rickets but also play a role in cancers,
multiple sclerosis, infection, hypertension, and diabetes
mellitus. Some individuals with seemingly adequate UV
exposure have been reported to have low serum 25-hydroxyvitamin D
(25[OH]D) concentration; however, the cutoff value to
define low vitamin D status and the definition for
successful vitamin D repletion therapy remain
controversial.

The aim of this study was to document the 25(OH)D
status of healthy individuals with habitually high s
un exposure and to identify a target value of 25(OH)D
for use in vitamin D therapy.

Study Highlights

In late March 2005, this study was conducted in a
sample of 93 adults (30 women, 63 men) in Honolulu,
Hawaii (latitude 21°). Overall, the mean (SEM) age and
body mass index were 24.0 years (0.7) and 23.6 kg/m2
(0.4), respectively. Volunteers were required to
have self-reported sun exposure of 3 or more hours
per day on 5 or more days per week for at least the
preceding 3 months. Their self-reported sun exposure
was 28.9 hours per week (1.5), yielding a calculated
sun exposure index of 11.1 (0.7).
To further document sun exposure, skin color was measured
with the L scale, which ranges from 0 (black) to 100 (white).
The main outcome measured was the serum 25(OH)D concentration,
using a precise high-performance liquid chromatography assay.
Low vitamin D status was defined as a circulating 25(OH)D
concentration of less than 30 ng/mL.
Results revealed that the mean serum 25(OH)D
concentration was 31.6 ng/mL. The highest 25(OH)D
concentration was 62 ng/mL.
Using a cutpoint value of 30 ng/mL, 51% of this population
had low vitamin D status.
There was no correlation between serum whole parathyroid
hormone value and 25(OH)D concentration.
Moreover, there was no correlation between serum 25(OH)D
measured by high-performance liquid chromatography and age,
lightest or darkest skin color, change in skin color,
hours per week of sun exposure without sunscreen, or
body mass index. To evaluate determinants of serum 25(OH)D status,
individuals (n = 23) with the lowest circulating l
evels of 25(OH)D were compared with the remaining cohort.
Those with the lowest levels had higher parathyroid hormone
values and significantly lower sun exposure score and change
in skin color. Limitations to this study include the
cross-sectional design and self-report of sun exposure.

Pearls for Practice

Low vitamin D levels contribute to the development of
osteoporosis and osteomalacia/rickets and may play a role
in cancers, multiple sclerosis, infection, hypertension,
and diabetes mellitus.
Variable responsiveness to UV-B radiation is evident among
individuals and causes some to have low vitamin D status
despite abundant sun exposure. In addition, the maximal
25(OH)D concentration produced by natural UV exposure
appears to be approximately 60 ng/mL; this value may be
used as an upper limit when prescribing vitamin D
supplementation.