Low testosterone levels and the risk of anemia in older men and women

Abstract

Background: Anemia is a frequent feature of male hypogonadism and anti-androgenic treatment. We hypothesized that the presence of low testosterone levels in older persons is a risk factor for anemia.

Methods: Testosterone and hemoglobin levels were measured in a representative sample of 905 persons 65 years or older without cancer, renal insufficiency, or anti-androgenic treatments. Hemoglobin levels were reassessed after 3 years.

Results: At baseline, 31 men and 57 women had anemia. Adjusting for confounders, we found that total and bioavailable testosterone levels were associated with hemoglobin levels in women (P = .001 and P = .02, respectively) and in men (P<.001 and P = .03, respectively). Men and women in the lowest quartile of total and bioavailable testosterone were more likely than those in the highest to have anemia (men, 14/99 vs 3/100; odds ratio [OR], 5.4; 95% confidence interval [CI], 1.4-21.8 for total and 16/99 vs 1/99; OR, 13.1; 95% CI, 1.5-116.9 for bioavailable testosterone; women, 21/129 vs 12/127; OR, 2.1; 95% CI, 0.9-5.0 for total and 24/127 vs 6/127; OR, 3.4; 95% CI, 1.2-9.4 for bioavailable testosterone). Among nonanemic participants and independent of confounders, men and women with low vs normal total and bioavailable testosterone levels had a significantly higher risk of developing anemia at 3-year follow-up (21/167 vs 28/444; relative risk, 2.1; 95% CI, 1.1-4.1 for total and 26/143 vs 23/468; relative risk, 3.9; 95% CI, 1.9-7.8 for bioavailable testosterone).

Conclusion: Older men and women with low testosterone levels have a higher risk of anemia.

Figure 1

Relationship of total and bioavailable testosterone levels with hemoglobin level in all InCHIANTI participants and restricted to those with normal serum iron levels and no deficiencies of iron, cyanocobalamin (vitamin B₁₂), or folate. Hemoglobin values are age adjusted. The relationships are summarized using locally weighted regression smoothers. To convert testosterone to nanomoles per liter, multiply by 0.0347.

Figure 2

Crude and age-adjusted prevalence of anemia according to total and bioavailable testosterone level quartiles in all InCHIANTI participants and restricted to cases of unexplained anemia (ie, normal serum iron levels and no deficiencies of iron, cyanocobalamin (vitamin B₁₂), or folate. To convert testosterone to nanomoles per liter, multiply by 0.0347.