Effect of Testosterone Treatment on Leucocyte Telomere Length in Men: Results From a Randomised Placebo-Controlled Trial.

BACKGROUND: Lower testosterone concentrations in older men are associated with poorer health outcomes. OBJECTIVE: We examined whether, on a background of lifestyle intervention, testosterone treatment modulates leucocyte telomere length, a postulated marker of biological ageing, in overweight men with impaired glucose tolerance (IGT) or newly diagnosed type 2 diabetes (T2D). PARTICIPANTS AND METHODS: We conducted a secondary analysis of a randomised, placebo-controlled trial in 50- to 74-year-old men with waist circumference ≥ 95 cm and dysglycaemia (ACTRN12612000287831). All men received a background lifestyle program, and were randomised to 2 years treatment with intramuscular testosterone undecanoate (1000 mg) every 3 months or placebo. Leucocyte telomere length was assayed by multiplex quantitative polymerase chain reaction and expressed as relative telomere length (rTL), a ratio of telomeric DNA to β-globin, a single-copy control gene (T/S ratio). RESULTS: There were 720 participants, aged 60 ± 6 years (mean ± SD), 38% had BMI 30-34.99 kg/m2 and 44% ≥ 35 kg/m2. Mean rTL at baseline was 1.63 ± 0.27 in testosterone-treated men (N = 375) and 1.61 ± 0.28 in placebo-treated men (N = 345). At 2 years, mean rTL was 1.61 ± 0.28 and 1.58 ± 0.29, respectively. Change in rTL after 2 years treatment was -0.02 ± 0.15 in testosterone-treated and -0.03 ± 0.12 in placebo-treated men. Adjusting for baseline values there was no effect of testosterone treatment on rTL at 2 years (mean difference 0.01 [95% CI, -0.01 to 0.03], p = 0.24). Results were similar for rTL change at 2 years from baseline. CONCLUSIONS: There was no effect of testosterone treatment on telomere length in this group of men. Larger studies with longer treatment durations are merited.