women older than 65 years of age with low testosterone
levels are at increased risk of being or becoming anemic,
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 Medicine. "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
he 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
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.