July 14, 2006

Older adults with low testosterone prone to anemia

By Megan Rauscher

NEW YORK (Reuters Health) - Men and women older than 65
years of age with low testosterone levels are at increased risk
of being or becoming anemic, researchers report.

While testosterone is considered the 'male' hormone, women
normally have some -- albeit at lower levels than men.

"Low testosterone levels could be a susceptibility factor
for anemia that has been generally neglected," Dr. Luigi
Ferrucci, from the National Institute on Aging in Baltimore,
Maryland, and colleagues suggest in the Archives of Internal

"Low testosterone levels," they write, "should be
considered a potential cause or co-cause of anemia in older men
and women, especially when other plausible causes have been
excluded, and in patients with nutritional deficiencies in whom
nutritional supplementation of iron and vitamins has been

The team's findings are based on an Italian
population-based study, in which testosterone and hemoglobin
levels were measured in a representative sample of 905 older
adults, 65 years of age or older.

Hemoglobin is the oxygen-carrying component of red blood
cells. Anemia was defined as a concentration of hemoglobin
below 12 grams per deciliter of blood for women and below13
grams per deciliter for men.

At the start of the study, 31 men and 57 women had anemia,
based on their hemoglobin measurement.

Men with the lowest levels of testosterone were five times
more likely to be anemic than men with the highest levels, the
researchers report. For women, low testosterone doubled the
likelihood of anemia.

Among those without anemia at baseline, men and women with
low versus normal testosterone had a significantly higher risk
of developing anemia within three years.

Despite the statistically significant association between
low testosterone level and low hemoglobin level, many subjects
with low testosterone were not anemic and many of those who
were anemic had testosterone levels in the normal range.

"These findings," write the authors, "suggest that a low
testosterone level increases susceptibility to anemia but may
not be a sufficient causal factor for anemia, probably because
the effect can be counteracted by alternative mechanisms."

Summing up, Ferrucci and colleagues conclude that anemia in
older adults is likely to be the result of multiple factors.
Understanding the causes of anemia in this population is
important "because anemia in older persons is frequently
unexplained and is associated with a high risk of disability
and accelerated decline in physical function," they point out.

SOURCE: Archives of Internal Medicine, July 10, 2006.