TY - JOUR
T1 - Effects of testosterone supplementation on separate cognitive domains in cognitively healthy older men
T2 - a meta-analysis of current randomized clinical trials
AU - Tan, Sherilyn
AU - Sohrabi, Hamid R.
AU - Weinborn, Michael
AU - Tegg, Michelle
AU - Bucks, Romola S.
AU - Taddei, K.
AU - Carruthers, Malcolm
AU - Martins, Ralph N.
PY - 2019/11
Y1 - 2019/11
N2 - Background: An increasing body of literature suggests a positive, neuroprotective effect for testosterone on cognition in older men. However, randomized clinical trials (RCTs) examining the effects of testosterone supplementation (TS) on cognitive function have been inconclusive. Objective: To investigate the potential for TS to prevent cognitive decline in otherwise cognitively healthy older men, by examining the differential effects of TS on cognitively healthy older men in RCTs. Methods: Comprehensive search of electronic databases, conference proceedings, and grey literature from 1990 to 2018 was performed to identify RCTs examining the effects of TS on cognition before and after supplementation, in cognitively healthy individuals. Results: A final sample of 14 eligible RCTs met inclusion criteria. Using pooled random effects expressed as Hedge's g, comparison of placebo versus treatment groups pre- and postsupplementation showed improvements in the treatment group in executive function (g (11) = 0.14, 95% confidence interval [CI]: 0.03–0.26, z = 0.56, p = 0.011). However, it was noted that two studies in our sample did not report a significant increase in mean serum total testosterone (TT) levels in the treatment group after supplementation. Following exclusion of these studies, analysis indicated improvement in the treatment group for the overall cognitive composite (g (11) = 0.18, 95% CI: 0.02–0.33, z = 2.18), psychomotor speed (g (3) = 0.22, 95% CI: 0.01–0.43, z = 2.07) and executive function (g (9) = 0.15, 95% CI: 0.03–0.28, z = 2.35). No significant differences were noted for the global cognition, attention, verbal memory, visuospatial ability or visuospatial memory domains. Conclusion: Overall, our findings support the potential for TS as a preventative measure against cognitive decline, although the effect sizes were small. These findings warrant further observational studies and clinical trials of good methodological quality, to elucidate the effect of TS on cognition.
AB - Background: An increasing body of literature suggests a positive, neuroprotective effect for testosterone on cognition in older men. However, randomized clinical trials (RCTs) examining the effects of testosterone supplementation (TS) on cognitive function have been inconclusive. Objective: To investigate the potential for TS to prevent cognitive decline in otherwise cognitively healthy older men, by examining the differential effects of TS on cognitively healthy older men in RCTs. Methods: Comprehensive search of electronic databases, conference proceedings, and grey literature from 1990 to 2018 was performed to identify RCTs examining the effects of TS on cognition before and after supplementation, in cognitively healthy individuals. Results: A final sample of 14 eligible RCTs met inclusion criteria. Using pooled random effects expressed as Hedge's g, comparison of placebo versus treatment groups pre- and postsupplementation showed improvements in the treatment group in executive function (g (11) = 0.14, 95% confidence interval [CI]: 0.03–0.26, z = 0.56, p = 0.011). However, it was noted that two studies in our sample did not report a significant increase in mean serum total testosterone (TT) levels in the treatment group after supplementation. Following exclusion of these studies, analysis indicated improvement in the treatment group for the overall cognitive composite (g (11) = 0.18, 95% CI: 0.02–0.33, z = 2.18), psychomotor speed (g (3) = 0.22, 95% CI: 0.01–0.43, z = 2.07) and executive function (g (9) = 0.15, 95% CI: 0.03–0.28, z = 2.35). No significant differences were noted for the global cognition, attention, verbal memory, visuospatial ability or visuospatial memory domains. Conclusion: Overall, our findings support the potential for TS as a preventative measure against cognitive decline, although the effect sizes were small. These findings warrant further observational studies and clinical trials of good methodological quality, to elucidate the effect of TS on cognition.
KW - ageing
KW - Alzheimer's disease
KW - cognitive decline
KW - cognitive function
KW - hypogonadism
KW - memory
KW - Testosterone supplementation
UR - http://www.scopus.com/inward/record.url?scp=85068468185&partnerID=8YFLogxK
U2 - 10.1016/j.jagp.2019.05.008
DO - 10.1016/j.jagp.2019.05.008
M3 - Review article
C2 - 31296441
AN - SCOPUS:85068468185
SN - 1064-7481
VL - 27
SP - 1232
EP - 1246
JO - American Journal of Geriatric Psychiatry
JF - American Journal of Geriatric Psychiatry
IS - 11
ER -