“What was unique about our approach is that we measured memory function and sexual function at each point in the longitudinal study, so we could look at how they changed together over time,” said Martin Sliwinski, professor of human development and family studies at Penn State and co-author on the study. “What we found connects to what scientists are beginning to understand about the link between life satisfaction and cognitive performance.”
The study explored the relationship between physical changes like the microvascular changes relevant for erectile function, and psychological changes, such as lower sexual satisfaction, to determine how the changes relate to cognition. They examined the shifts starting in middle age because it represents a transition period where declines in erectile function, cognition and sexual satisfaction begin to emerge.
Sliwinski added that while the team discovered a strong correlation between the three health factors, they can only speculate as to the cause.
“Scientists have found that if you have low satisfaction generally, you are at a higher risk for health problems like dementia, Alzheimer’s disease, cardiovascular disease and other stress-related issues that can lead to cognitive decline,” he said. “Improvements in sexual satisfaction may actually spark improvement in memory function. We tell people they should get more exercise and eat better foods. We’re showing that sexual satisfaction also has importance for our health and general quality of life.”
For the study, the researchers used survey data from 818 men who participated in the Vietnam Era Twin Study of Aging. Through neuropsychological tests, such as tests of memory and processing speed, they examined cognitive changes of participants over the 12-year span from age 56 to 68, adjusting for participants’ cognitive ability in young adulthood. Their erectile function and sexual satisfaction were measured alongside cognition, using the International Index of Erectile Function, a self-reported assessment for male sexual health. The researchers then built a statistical model to understand how the three variables changed as individuals aged.
“Research on sexual health has historically focused on quantifiable facets of sexuality like number of sexual partners or frequency of sexual activity,” said Riki Slayday, a doctoral candidate at Penn State and lead author on the study. “What we were interested in is the perception of that activity, how someone feels about their sex life, and how that influences cognitive function, because multiple people could be in the same situation physically but experience completely different levels of satisfaction.”
The study found that decreases in erectile function and sexual satisfaction were both associated with memory decline, which the researchers say points to a connection between psychological and physical health.
“When we mapped the relationship over time, we found increases or decreases in erectile function and sexual satisfaction were associated with concurrent increases or decreases in cognitive function,” Slayday said. “These associations survived adjustment for demographic and health factors, which tells us there is a clear connection between our sex lives and our cognition.”
Prior studies have found a link between microvascular changes and changes in erectile function over time. In fact, the active ingredient in Viagra (Sildenafil) was originally developed to treat cardiovascular problems, Sliwinski explained, so the connection between vascular health and erectile function is well understood. How erectile function connects to other aspects of health should be an area of focus for future research, he added.
Increasing the assessment and monitoring of erectile function as a vital sign of health may help identify those at risk of cognitive decline before their 70s, he said. The researchers note that the older adult population in the U.S. is expected to double over the next 30 years, which means twice as many people will likely enter their 60s and experience declines in erectile function and sexual satisfaction.
“We already have a pill for treating erectile dysfunction. What we don’t have is an effective treatment for memory loss,” Sliwinski said. “Instead of the conversation being about treating ED, we should see that as a leading indicator for other health problems and also focus on improving sexual satisfaction and overall well-being, not just treating the symptom.”
Other co-authors on the paper are Tyler Bell, Teresa Warren, William Kremen and Carol Franz of the University of California San Diego; and Michael Lyons, Rosemary Toomey and Richard Vandiver of Boston University.
The work was supported the National Institute on Aging at the National Institutes of Health.
