Variations in male sex hormones linked to Reduced testosterone and increased LH levels in old age

New research found that multiple factors like systemic diseases, age, marital status, and habits like smoking are associated with the variations in male sex hormones like testosterone, sex hormone binding globulin, and luteinizing hormone in older ages. Among these, reduced levels of testosterone and increased levels of luteinizing hormones affecting the BMI are signs of reduced testicular function after 70 years of age. 

The study was published in the journal Annals of Internal Medicine on 29th August 2023. 

Testosterone has vital functions in the body like controlling libido in men, bone mass, fat distribution, muscular mass, and strength, as well as the creation of sperm and red blood cells. Literature shows that multiple factors are associated with changing levels of circulating testosterone. As there is limited data on the association of circulating testosterone on the human body, researchers conducted a Systematic review and individual Participant Data Meta-analyses to clarify factors associated with variations in sex hormone concentrations. 

All the prospective cohort studies of community-dwelling men with total testosterone that were measured using mass spectrometry were taken for the study. Data extracted was mainly the individual participant data (IPD), aggregate data, Sociodemographic, lifestyle, and health factors, and concentrations of total testosterone, sex hormone–binding globulin (SHBG), luteinizing hormone (LH), dihydrotestosterone, and estradiol. 

Results: 

• Two-stage random-effects IPD meta-analyses found a nonlinear association of testosterone with age, with negligible change among men aged 17 to 70 years and decreasing testosterone levels with age for men older than 70 years. 
• Testosterone was inversely associated with body mass index (BMI).
• Testosterone concentrations were lower for men who were married; undertook at most 75 minutes of vigorous physical activity per week; were former smokers; or had hypertension, cardiovascular disease, cancer, or diabetes.
• Sex hormone–binding globulin was directly associated with age and inversely associated with BMI.
• The Luteinizing hormone was directly associated with age in men older than 70 years. 

Thus, BMI, age, and systemic conditions are some of the factors that vary the levels of testosterone in men. 

Further reading: Factors Associated With Circulating Sex Hormones in Men. Individual Participant Data Meta-analyses. https://doi.org/10.7326/M23-0342