MONDAY, Oct. 18 (HealthDay News) -- People with a genetic
predisposition to basal cell carcinoma -- the most common form of
skin cancer -- may trade one health risk for another, a new study
suggests.
Because people with basal cell nevus syndrome (BCNS) tend to
develop multiple basal cell skin cancers in early adulthood and so
take more precautions against sun exposure, they may also run a
higher risk of being deficient in vitamin D, report researchers in
the October issue of
Archives of Dermatology.
"We found that patients with skin cancer who practice very good photoprotection [sun protection] have lower vitamin D levels," said Dr. Jean Tang, lead author of the study. "This makes sense because they're avoiding sunlight and sun is required to synthesize vitamin D."
But having healthy levels of the nutrient may be necessary to
protect against cancer, broken bones, heart disease and even some
autoimmune diseases.
The study authors looked back at the medical records of 41
patients with BCNS who had previously been involved in a trial to
see if the non-steroidal anti-inflammatory drug Celebrex
(celecoxib) might prevent against basal cell carcinomas. According
to the authors, Celebrex is not known to affect vitamin D levels in
the body.
These individuals were matched against 360 men and women who did
not have the cancer syndrome but who were of similar ages, similar
weight, similar UV (ultraviolet) exposure and who lived in similar
geographic areas
Eighty percent of the BCNS patients said they used sunscreen
every day, avoided the sun during its hottest hours in the middle
of the day and wore long-sleeved clothing.
And in this sample, 56 percent of participants with BCNS had
too-low levels of vitamin D -- three times as many as in the
control group.
"Most likely," said Tang, "the fact that skin cancer patients avoid sunlight is probably the number-one contribution to why they have low vitamin D levels, because the major difference between the two groups was that the skin cancer patients were practicing good photoprotection."
But at this point, the evidence for a link between sun
protection and vitamin D deficiency is still an indirect one, said
Dr. Vijay Trisal, an assistant professor of surgical oncology at
City of Hope Cancer Center in Duarte, Calif., who was not involved
in the study.
He also noted that a large number of people both with and
without histories of skin cancer have vitamin D levels that are
deficient.
Rather than basking in the sun or trading long-sleeved shirts
for sleeveless, the authors suggest that wider screening of vitamin
D levels would be a first step in resolving this problem. Vitamin D
supplementation for those who are deficient could follow, said
Tang, who is assistant professor of dermatology at Stanford
University Medical Center.
Right now, the recommended daily allowance of vitamin D is 400
international units, but the Institute of Medicine is currently
revisiting those numbers. A new report is expected at the end of
November, Tang said.
The bottom line, according to Trisal: "It's easy to get adequate
doses of vitamin D by taking a tablet."
More information
Find out more about the vitamin D-skin cancer connection at the
Skin Cancer Foundation.