Hormone D Deficiency—
A Serious Endocrine Disorder.
Letter to the Editor
To the Editor:
In his review article in the September/October 2009 issue of Endocrine Practice, “Is Vitamin D the Fountain of Youth?” Dr. Neil Binkley compares vitamin D with vitamin E and vitamin K (1). This comparison is not justified
because vitamin D is not a vitamin but a hormone. Vitamin
D deficiency is a hormonal deficiency—an extremely common
endocrine disorder. Similar to other hormonal deficiencies,
hormone D deficiency (HDD) has a wide range of
We endocrinologists should approach our treatment
of HDD as we do hypothyroidism, diabetes, or hypogonadism.
You do not promise someone a “fountain of youth”
by prescribing levothyroxine, nor do you withhold insulin
from a patient with type 1 diabetes because you need more
studies to prove a causal relationship. Hormone D needs to
be replaced in patients who have this disorder, and let us
call this endocrine condition precisely what it is: hormone
D deficiency or HDD.
Dr. Binkley seems to underestimate the power of the
strong evidence linking HDD to a host of clinical manifestations
by labeling published reports collectively as observational
studies. In fact, many of the studies on hormone
D are not simple observational studies. For example, in a
laboratory model for multiple sclerosis, hormone D was
shown to prevent this disease completely (2). In patients
with diabetes, hormone D was shown to prevent the formation
of foam cells, the building blocks of atheromatous
HDD is the result of our modern lifestyle and sun
phobia, whereby skin cannot produce enough hormone
D. Receptors for hormone D are present in numerous tissues—
more specifically, bones, skeletal muscles, kidneys,
islet cells, mononuclear cells, cardiomyocytes, and nervous
tissues. Thus, it is no surprise that HDD may lead to a
wide array of clinical manifestations.
As endocrinologists, it is our responsibility to
and treat HDD in all our patients. Furthermore, we need to
educate our patients as well as other physicians about this
very real endocrine disorder instead of questioning its serious
nature by debating whether or not it fits the profile of
the mythical fountain of youth.
The author has no multiplicity of interest to disclose.
Sarfraz J. Zaidi, MD, FACP, FACE
Jamila Diabetes and Endocrine Medical Center, Inc.
1429 East Thousand Oaks Boulevard, Suite 105
Thousand Oaks, CA 91362
1. Binkley N. Is vitamin D the fountain of youth? Endocr
2. Hayes CE. Vitamin D: a natural inhibitor of multiple sclerosis.
Proc Nutr Soc. 2000;59:531-535.
3. Oh J, Weng S, Felton SK, et al. 1,25(OH)2 vitamin D
inhibits foam cell formation and suppresses macrophage
cholesterol uptake in patients with type 2 diabetes mellitus.
712 ENDOCRINE PRACTICE Vol 16 No. 4 July/August 2010