“A major finding from our study is how multiple sociodemographic, lifestyle, and medical factors influence testosterone levels in men," says Bu B. Yeap, MBBS, FRACP, PhD.
Investigators have identified multiple factors that are associated with lower testosterone levels in men, including age over 70 years, obesity, diabetes, and cancer, according to findings published in Annals of Internal Medicine and highlighted in a news release.1,2
For the study, investigators from the University of Western Australia analyzed data from 11 studies across Australia, Europe, and North America. In total, 21,074 men were identified for analysis from individual participant data, and 4075 men were identified via aggregate data studies. Total testosterone levels were measured using mass spectrometry. Sex hormone-binding globulin, luteinizing hormone, dihydrotestosterone, and estradiol were also measured.
Data showed no significant change in testosterone levels among men aged 17 to 70 years, but levels began decreasing among men older than 70 years. Luteinizing hormone concentrations also began increasing among men who were over the age of 70.
Senior author Bu B. Yeap, MBBS, FRACP, PhD, commented in correspondence with Urology Times®, “After [the age of 70], testosterone levels declined with age, despite increasing levels of the pituitary hormone that drives testosterone production by the testis. This indicates that production of testosterone by the testis is impaired after the age of 70 years.”
Testosterone levels were also found to have an inverse relationship with body mass index (BMI), where a higher BMI indicated lower levels of testosterone. Sex hormone-binding globulin was similarly found to be directly associated with age and inversely with BMI.
“Another interesting finding was that married men (or men in a de facto relationship) had slightly lower testosterone levels than single men. A possible explanation could be that married men with families might be more stressed, and therefore have lower testosterone levels, but our study wasn’t designed to look further into this result,” added Yeap, who is a professor at the University of Western Australia Medical School and a consulting endocrinologist at Fiona Stanley Hospital in Perth, Australia.
Further, participants who were former smokers were more likely to have lower levels of testosterone compared with men who had never smoked. Lower levels of testosterone were also linked with hypertension, heart disease, those on cholesterol-lowering medications, those who were less physically active (defined as at most 75 minutes of vigorous activity per week), and those with a history of diabetes or cancer.
Yeap concluded, “A major finding from our study is how multiple sociodemographic, lifestyle, and medical factors influence testosterone levels in men. These factors should be considered when clinicians interpret testosterone results from individual men, as testosterone levels might be lower in the presence of these conditions, rather than being always due to a problem with the testes.”
1. Marriott RJ, Murray K, Adams RJ, et al. Factors associated with circulating sex hormones in men: individual participant data meta-analyses. Ann Intern Med. Published online August 29, 2023. Accessed August 30, 2023. doi:10.7326/M23-0342
2. After age 70, higher BMI and the presence of diabetes or cancer associated with lower testosterone in men. News release. August 22, 2023. Accessed August 30, 2023. https://www.newswise.com/articles/after-age-70-higher-bmi-and-the-presence-of-diabetes-or-cancer-associated-with-lower-testosterone-in-men?ta=home