Vitamins A and D Improve Bone Health in Children and Adults
PA, 19 June 2003
Presented at ENDO 2003, the 85th Annual Meeting of The Endocrine
research highlights the important role that vitamins A and D play
in bone health and identifies a common and previously under-appreciated
relationship in postmenopausal women.
of the new studies found that vitamin D deficiency is much more
frequent among African American children and adults than previously
thought, while a third finds that high and low levels of vitamin
A can increase hip fractures in older women. A fourth study discovered
a relationship between hypercalciuriaa condition that causes
loss of calcium through urineand bone fractures in postmenopausal
four studies will be presented during ENDO 2003, the 85th Annual
Meeting of The Endocrine Society, beginning June 20 at the Pennsylvania
Convention Center in Philadelphia, PA.
adolescent years, nutritional problems such as vitamin D deficiency
can have a negative impact on bone density. In adults, low levels
of vitamin D can be responsible for low dietary calcium absorption
as well as hyperparathyroidisma condition that occurs when
the parathyroid gland, which is located in the neck, produces too
much parathyroid hormone. When this happens, there is too much calcium
in the patient's blood. Hyperparathyroidism can cause fatigue, disorientation,
and depression, and can also lead to bone loss and kidney stones.
new studies reveal that vitamin D deficiency is widespread among
African American adolescents and women. In one study, researchers
measured vitamin D levels in more than two hundred adolescents.
Eighteen percent of the subjects tested positive for vitamin D deficiency,
which was equal in boys and girls, but more prevalent in African
Americans and during the winter months. Researchers also discovered
a correlation between lifestyle variables and vitamin D deficiency.
who took vitamins as well as calcium supplements and exercised regularly
were less likely to suffer from vitamin D deficiency," explains
Dr. Catherine Gordon, an endocrinologist at Children's Hospital
in Boston. "Our findings suggest that vitamin D deficiency is common
among adolescents. It is critical that we find ways to help adolescents
maintain healthy levels of vitamin D to avoid skeletal problems
as they age."
a second study on vitamin D, researchers found an extremely highnearly
65 percentprevalence rate of vitamin D deficiency among obese
African Americans, particularly in African American women. In the
study, researchers compared the levels of vitamin D deficiency in
overweight African American and Caucasian subjects. Many of the
subjects with vitamin D deficiency were also found to suffer from
secondary hyperparathyroidism as a result of their low levels of
already know that dark skin pigment and increased body weight put
people at higher risk for developing vitamin D deficiency," notes
Dr. Shamik Parikh, a clinical investigator at the National Institute
of Child Health and Human Development. "Our findings suggest that
obese African Americans, especially women, should be regularly screened
for vitamin D deficiency."
studies have shown that high intake of vitamin A can be associated
with lower bone density and increased risk of fracture. The new
research has generally focused on populations with high intake of
at Columbia University's College of Physicians and Surgeons in New
York City sought to determine whether high and low levels of vitamin
A placed postmenopausal women at an increased risk for hip fractures.
The doctors used the United States government's NHANES I survey,
which began in the 1970s. NHANES I has information now from a 22-year
follow-up of nearly three thousand women. One hundred and seventy
nine women in the study experienced hip fractures during the study
and follow-up. Researchers divided these women into five groups,
or quintiles, based on their vitamin A levels.
with the highest vitamin A levels and lowest vitamin A levels were
both twice as likely to experience a hip fracture when compared
with women who had average levels of vitamin A," said Dr. Alexander
Opotowsky, the lead investigator in the study. "This is the first
time that a study has demonstrated increased hip fractures at both
ends of the vitamin A concentration curve."
investigators note that these new results may prompt the medical
community to reassess recent calls to decrease vitamin A supplementation
among general populations. Dr. Opotowsky explains that for some
people, vitamin A supplementations may increase fracture risk, but
for people with low vitamin A levels, supplementation may be a benefit.
analysis suggests that small amounts of vitamin A may not influence
overall hip fracture rates. However, without knowing the vitamin
A status of an individual, eliminating vitamin A supplements could
actually increase the number of vitamin A deficient individuals,
which would put them at further risk not only for hip fractures,
but also for other health risks associated with low vitamin A,"
explains Dr. Opotowsky.
is a condition where a person loses calcium through their urine.
Studies have shown that vertebral fractures are more common among
people with hypercalciuria. However, until now, the percentage of
people with hypercalciuria who suffer from fractures has not been
in Italy studied about 13,000 men and women over a 10-year period
and found 46 males and about 1,200 females with hypercalciuria.
Through x-rays of the hypercalciuric men and women, researchers
found that 85 percent of males and 21 percent of females with hypercalciuria
3.7 percent of women in the general public experience fractures,"
said Dr. Maurizio Bevilacqua, a researcher at Luigi Sacco-Polo University
Hospital in Milano, Italy. "According to our findings, this number
increases to about 21 percent in postmenopausal women with hypercalciuria.
Testing for hypercalciuria, which is a simple and inexpensive exam,
could identify postmenopausal women who are at risk for vertebral
The Endocrine Society
Endocrine Society is the world's oldest, largest, and most active
organization devoted to research on hormones, and the clinical practice
of endocrinology. Endocrinologists are specially trained doctors
who diagnose, treat and conduct basic and clinical research on complex
hormonal disorders such as diabetes, thyroid disease, osteoporosis,
obesity, hypertension, cholesterol and reproductive disorders. Today,
The Endocrine Society's membership consists of over 10,000 scientists,
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Together, these members represent all basic, applied, and clinical
interests in endocrinology. The Endocrine Society is based in Bethesda,