Testosterone, SHBG and Incident Dementia Risk in Men

Takeaway

Middle-aged and older men with low testosterone levels had an increased risk of incident dementia and Alzheimer’s disease (AD).
Men with low sex hormone-binding globulin (SHBG) levels had a lower risk of incident dementia and AD.
The associations of testosterone with incident dementia were independent of SHBG levels and vice versa.

Why this matters

Findings warrant further interventional studies to investigate the potential causality of the associations and the underlying mechanisms.

Study design

A study included 159,411 community-dwelling men (age, 37-73 years) from the UK Biobank.
Primary outcome: new diagnosis of dementia from any cause.
Funding: Western Australian Health Translation Network and others.

Key results

During the follow-up of 7 years, 826 of 159,411 community-dwelling men developed dementia, including 288 from AD.
Compared with men with testosterone level in the highest quintile (Q5), those with low total testosterone level in the lowest quintile (Q1) had a higher risk of (adjusted HR [aHR]; 95% CI):
- incident dementia (1.43; 1.13-1.81; P = .001); and
- AD (1.80; 1.21-2.66; P = .017).
Compared with men with SHBG level in the highest quintile (Q5), those with low total SHBG level in lowest quintile (Q1) had a lower risk of (aHR; 95% CI):
- incident dementia (0.66; 0.51-0.85; P < .001); and
- AD (0.53; 0.34-0.84; P = .012).

Limitations

Observational design.
Data on incident dementia and AD cases were determined using linked hospital admissions and mortality data.

Marriott RJ, Murray K, Flicker L, Hankey GJ, Matsumoto AM, Dwivedi G, Antonio L, Almeida OP, Bhasin S, Dobs AS, Handelsman DJ, Haring R, O'Neill TW, Ohlsson C, Orwoll ES, Vanderschueren D, Wittert GA, Wu FCW, Yeap BB. Lower serum testosterone concentrations are associated with a higher incidence of dementia in men: The UK Biobank prospective cohort study. Alzheimers Dement. 2022 Jan 03 [Epub ahead of print]. doi: 10.1002/alz.12529. PMID: 34978125 View abstract.

Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.

Cite this: Pavankumar Kamat. Testosterone, SHBG and Incident Dementia Risk in Men - Medscape - Jan 17, 2022.

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