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 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 ineffective."
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 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.