Serum testosterone levels correlate with haemoglobin in middle-aged and older men

Background: Lower testosterone levels are associated with anaemia in older men and women. The relation between testosterone and haemoglobin (Hb) in younger and middle-aged men is less well defined. The aim of the study was to examine the association between testosterone and Hb levels in men spanning middle to older ages. Methods: A cross-sectional analysis of 492 men aged 30.7-94.5 years from the Busselton Health Survey, Western Australia, was carried out. Haemoglobin (Hb), early-morning serum total testosterone and sex hormone-binding globulin (SHBG) were measured. Free testosterone was calculated using mass action equations. Results: Haemoglobin correlated to total and free testosterone concentrations (r = 0.13, P = 0.003 and r = 0.20, P < 0.001, respectively). Hb and SHBG were inversely correlated (r = -0.14, P = 0.001). Hb increased across lowest to highest quartiles of total testosterone (P = 0.02) and free testosterone (P < 0.001), but not SHBG. After adjusting for age, waist circumference, smoking status, alcohol consumption, renal function and ferritin, total testosterone was associated with Hb (beta = 0.037, P = 0.003) as was free testosterone (beta = 2.32, P < 0.001), whereas SHBG was not associated. Conclusion: Testosterone concentration modulates Hb levels in community-dwelling men across a wide age range. Further studies are needed to clarify implications of this association between testosterone and Hb in men.