A recent study suggests men’s testosterone levels are significantly affected by their health and lifestyle choices.
Testosterone levels reduce by about one percent a year in men over 40. A team from the New England Research Institutes in Massachusetts investigated the influence of modifiable factors such as body mass index (BMI).
Dr. Thomas Travison and colleagues analyzed data on 1,667 Boston men ages 40 through 70. The men were followed for up to 16 years as part of the Massachusetts Male Aging Study (MMAS), a long-term study looking at men’s health and hormones. It encompasses the participants’ chronic illness, smoking, alcohol consumption, diet, and exercise levels.
The men were recruited between 1987 and 1989, and followed up with at two time points – 1995 to 1997, and 2002 to 2004. During follow-up, there were substantial increases in chronic illness and weight, and a rise in smoking and prescription drug-taking.
The researchers found the usual decline in testosterone with age. But they also found that moving from a non-obese to an obese BMI category was linked to a reduction in testosterone equivalent to 10 years of aging. The loss of a spouse also was associated with a 10-year equivalent reduction in testosterone.
“Many health and lifestyle changes were associated with accelerated decline,” the team reported in a recent article in the Journal of Clinical Endocrinology and Metabolism. “Co-morbidities and lifestyle influences may be as strongly associated with declining testosterone levels as is aging itself over the short- to mid-term.” But it cannot be proved that these lifestyle changes are the cause of testosterone declines.
Low testosterone levels may contribute to myriad health conditions, including diabetes, osteoporosis and impaired sexual function.
The researchers made a distinction between aging and “para-aging,” the avoidable conditions common among older adults. They suggested that health and lifestyle factors could be managed to help slow age-related testosterone decline.
Previous studies have suggested that testosterone decline also is linked to Alzheimer’s disease, but the link is unclear. The drop could be a result of the disease process instead.
Recently, Dr. Oliver Beauchet of Saint-Etienne University Hospitals, France analyzed all the available literature on testosterone and cognitive function in older men. He found that, overall, lower levels of testosterone in healthy older men are linked to poorer performance on cognitive tests. Results also indicate that testosterone supplements may have “moderate positive effects on selective cognitive domains (e.g. spatial ability)”, Dr Beauchet wrote in the European Journal of Endocrinology.
He recommended measuring testosterone levels in older men who show signs of cognitive impairment, and that supplementation be considered if levels are low. But he added that large, long-term studies on the effects of testosterone supplements for cognitive function are still needed.
Travison T. G. et al. The relative contributions of aging, health, and lifestyle factors to serum testosterone decline in men. Journal of Clinical Endocrinology and Metabolism, published online Dec. 5, 2006.
Rosario E. R. et al. Age-Related Testosterone Depletion and the Development of Alzheimer Disease. The Journal of the American Medical Association, Vol. 292, Sept. 22, 2004, pp. 1431-32.
Beauchet O. Testosterone and cognitive function: current clinical evidence of a relationship. The European Journal of Endocrinology, Vol. 155, December 2006, pp. 773-81.