A recent study followed middle-aged and older men over time to see if problems with getting and maintaining erections might affect their ability to think and remember things. The researchers found that those who had trouble with their erections also tended to have trouble with their memory and thinking skills. These men also seemed to experience memory decline faster as they got older. The study was published in the Gerontologist.
The past century has seen a notable increase in life expectancy worldwide. At the beginning of the 20th century, global life expectancy (how long an average person is expected to live) was only 30 to 40 years. As of the early 21st century, the average global life expectancy is closer to 70 to 75 years. It nearly doubled over the span of 100 years. This increase can be attributed to advancements in healthcare, sanitation, nutrition, and disease prevention.
However, longer lives also mean that the share of elderly individuals in the population is increasing. This increase in the share of the population of older individuals is further accelerated by a worldwide decrease in birth rates. By 2050, the older adult population is expected to triple.
This means that medical conditions that typically develop in older age will become much more common. These conditions include cognitive impairments and related disorders such as Alzheimer’s disease. This is why developing ways to detect signs of cognitive impairments and medical cognitions associated with older age early is gaining ever more importance.
One such potential indicator is erectile function in men. Erectile function refers to a person’s ability to achieve and maintain an erection of the penis sufficient for satisfactory sexual activity. Erectile function in men is affected by a wide range of changes in physical health. Problems with erectile function tend to increase 10-fold as man enter their sixties, coinciding with declines in cognitive performance. That is the reason it might potentially be a good indicator of the status of other functions of the body.
Study author Riki E. Slayday and his colleagues wanted to explore the relationship between erectile function, sexual satisfaction, and cognitive performance in men from midlife to older adulthood. They were particularly interested in changes in episodic memory, executive function, and cognitive processing speed. The researchers hypothesized that erectile function and sexual satisfaction would decline as people age and that this decline would be associated with a decline in the three mentioned cognitive functions.
Slayday and his colleagues analyzed data from Vietnam Era Twin Registry members who participated in the Harvard Drug study. All study participants served in the U.S. military at some point between 1965 and 1975. The researchers analyzed data from 818 such men in total.
Data were collected in three waves. These participants were 56 years old on average at the first wave of data collection, between 2002 and 2008. The first follow-up (the second wave) was 6 years after the first. The final wave was 6 years after the second. In this study, the researchers analyzed data of participants who did not have erectile disfunction or mild cognitive impairment at the time of the first wave.
Participants completed assessments of erectile function, sexual satisfaction, and cognitive performance. Aspects of cognitive performance that researchers focused on in this study were episodic memory, executive function, and processing speed. They assessed episodic memory using recall scores from the California Verbal Learning Test-II, the Wechsler Memory Scale – III, and the Logical Memory and Visual Reproductions tests. Assessments of executive function came from the Stroop test, Delis Kaplan Executive Function System Trail Making Test, and the WMS-III Letter-Number Sequencing and Digit Span Task. Finally, processing speed was assessed using a choice and reaction time test, and the number of correctly named colors and words in certain conditions of the Stroop test.
The results showed that erectile function and sexual satisfaction indeed decreased with the age of participants. They were lower in later waves. Cognitive functions of participants also declined over the study period. Participants with lower erectile function at the start of the study tended to have lower levels of all three cognitive functions assessed.
Individuals who were older, single, were less sexually active, with poorer physical functioning, lower cognitive processing speed, and with higher depressive symptoms tended to have lower erectile function. Sexual satisfaction was not related to cognitive performance.
Individuals who had lower levels of erectile function at the start of the study (on average around age 56) showed faster cognitive decline as years progressed. When looking across study waves (i.e., across the years of the study) decreases in erectile function were related to declines in episodic memory. Increases in erectile function were associated with less steep decline in episodic memory. Looking at changes within an individual over time, changes in erectile function were not associated with changes to executive function and processing speed.
“Overall, we found that decreases in erectile function and sexual satisfaction were related to declines in episodic memory, and increases were related to less decline in episodic memory. These associations survived adjustment for demographic and health factors. Our study showed that in addition to effects at midlife, continuously measured declines in erectile function in thereafter correspond to declines in episodic memory. We found that erectile function was related to all cognitive domains at baseline and that men with lower erectile function at baseline had greater declines in memory over time,” the study authors concluded.
The study sheds light on the age-related changes of sexual and cognitive functions. However, it also has limitations that need to be taken into account. Notably, all participants were men, so the results cannot be generalized to women. Additionally, all participants were twins who served in the U.S. military. Results might not be the same among other demographic groups.
The paper, “Erectile Function, Sexual Satisfaction, and Cognitive Decline in Men From Midlife to Older Adulthood”, was authored by Riki E. Slayday, Tyler R. Bell, Michael J. Lyons, Teresa S. Warren, Rosemary Toomey, Richard Vandiver, Martin J. Sliwinski, William S. Kremen, and Carol E. Franz.