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<td><span style="font-family:Helvetica, sans-serif; font-size:20px;font-weight:bold;">PsyPost – Psychology News Daily Digest (Unofficial)</span></td>
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<td><a href="https://www.psypost.org/obesity-reduces-testosterone-and-sperm-count-by-disrupting-brain-circuits/" style="font-family:Helvetica, sans-serif; letter-spacing:-1px;margin:0;padding:0 0 2px;font-weight: bold;font-size: 19px;line-height: 20px;color:#222;">Obesity reduces testosterone and sperm count by disrupting brain circuits</a>
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<p><p>A recent study published in <a href="https://doi.org/10.1523/JNEUROSCI.0222-24.2024"><em>The Journal of Neuroscience</em></a> sheds light on how obesity can disrupt reproductive health in males by altering brain circuitry. The research used mice fed a high-fat diet to mimic human obesity and found that it caused chronic changes in brain connections. These changes led to reduced testosterone, lower sperm count, and diminished libido in the mice. The study provides evidence that obesity weakens communication between the brain circuits that control both feeding and reproduction, potentially explaining the link between obesity and reproductive issues in men.</p>
<p>The researchers were motivated to conduct this study because while it is well-known that obesity lowers testosterone in men, which impacts various functions like muscle mass, cognition, and reproductive health, the exact mechanisms by which obesity causes these changes are not fully understood. This knowledge gap is significant because obesity-related reproductive issues are becoming increasingly common.</p>
<p>Obese men often suffer from low testosterone levels, reduced sperm count, and poor sperm quality. This study aimed to understand how chronic obesity alters brain circuitry to produce these effects, hoping that understanding the mechanisms might eventually lead to treatments or interventions that can address reproductive dysfunction in obese men.</p>
<p>“A long-term goal of my research is to identify the molecular and cellular mechanisms that regulate reproductive function, which is necessary for the survival of the species,” said corresponding author Djurdjica Coss, a professor of biomedical sciences and associate vice chancellor for research at the University of California, Riverside School of Medicine.</p>
<p>“My research is significant to individuals struggling with unexplained infertility. Currently, 1 in 8 couples experience infertility and require assisted reproductive technologies to have a child. It is also important for the survival of endangered species, whose preservation depends on reproductive assistance, and for our food supply, as agricultural animals increasingly suffer from infertility due to modern farming practices. The studies in my lab may help identify new treatments and strategies to alleviate conditions that contribute to the rising infertility rates in both humans and animals.”</p>
<p>“An increase in infertility in the Western world has coincided with the growing prevalence of obesity, which now affects 35% of individuals in the United States,” Coss explained. “Obese individuals have a higher incidence of various diseases, including reproductive disorders. Obesity is known to lower testosterone in men, impacting muscle mass and cognition, as well as reproductive function by reducing sperm numbers and decreasing libido. The global rise in obesity may partly explain the decline in sperm counts that <a href="https://www.cnn.com/2022/11/18/health/sperm-counts-decline-debate/index.html">has been reported in the media</a>. However, the mechanistic links between obesity and infertility remain unclear.”</p>
<p>To mimic the effects of human obesity, the researchers used male mice fed a high-fat diet. These mice were compared to a control group that was fed a standard diet. After 12 weeks, the researchers measured the levels of luteinizing hormone (LH), a hormone critical for testosterone production and sperm development, to assess the impact of the high-fat diet on reproductive function.</p>
<p>The team specifically focused on two groups of neurons in the hypothalamus: proopiomelanocortin (POMC) neurons, which play a role in regulating energy balance and food intake, and kisspeptin neurons, which are crucial for controlling the release of gonadotropin-releasing hormone (GnRH) and, consequently, LH.</p>
<p>The researchers found that obesity caused significant changes in the brain’s reproductive circuitry. In obese mice, LH pulse frequency was reduced, leading to lower testosterone levels and reduced sperm counts. While the reproductive system retained its ability to function normally under direct stimulation, the chronic effects of obesity suppressed the activity of kisspeptin neurons, which are essential for triggering the release of GnRH and LH.</p>
<p>The team observed a reduction in the number of receptors on kisspeptin neurons that respond to αMSH, a molecule produced by POMC neurons that normally helps coordinate feeding and reproductive functions. This reduction in receptor availability weakened the communication between POMC and kisspeptin neurons, leading to a suppression of kisspeptin activity and reduced LH secretion.</p>
<p>Another key finding was that glutamatergic signaling, which is thought to help synchronize kisspeptin neuron activity, was reduced in obese mice. This decrease in glutamatergic input likely contributed to the impaired reproductive function observed in the high-fat diet group.</p>
<p>Despite these changes, the researchers found that when kisspeptin neurons were artificially activated through chemogenetic techniques, the LH response was greater in obese mice than in the control group, suggesting that the kisspeptin neurons were not permanently damaged but were being suppressed by the effects of obesity.</p>
<p>“The extent of changes was surprising,” Coss told <em>PsyPost</em>. “Our studies demonstrated that the brain is the primary site for obesity’s impact on reproductive function, specifically populations of neurons that regulate the reproductive hormone axis and food intake. Neurons in the brain are connected and communicate with each other via synapses. Neurons that regulate food intake and energy expenditure interact with neurons that regulate reproduction to coordinate their functions, since reproduction is an energy-demanding process.”</p>
<p>“Using mice fed a high-fat diet to mimic human obesity, my team found that obesity causes chronic changes in the brain. We showed that the brains of the chronically fat mice have fewer connections between neurons and a downregulation — a reduction in the number — of receptors that normally inform the brain that enough energy is available to stop food intake. This may explain why we don’t halt excessive calorie intake and why it is difficult to lose weight. We counted the number of synapses (connections) in the neurons that regulate reproduction in the brain and identified fewer synapses in the obese mice. We still don’t know exactly how this happens, but now, after identifying specific neuronal populations and specific synaptic molecules that are affected by obesity, we can design future studies to define mechanisms or identify treatments.”</p>
<p>Interestingly, the research team <a href="https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2018.01992/full" target="_blank" rel="noopener">previously reported</a> that while male mice fed a high-fat diet experienced significant reductions in LH levels, testosterone, and sperm counts, female mice did not show the same degree of reproductive impairment. This suggests that females may be more resistant to the negative reproductive effects of obesity compared to males.</p>
<p>“Our previous studies have shown that females gain weight more slowly, and that even after weight gain, females are somewhat protected from the significant negative effects of obesity,” Coss explained. “This also matches observations in humans, where males are more susceptible to cardiovascular disease and metabolic syndrome in obesity.”</p>
<p>“However, we expected more changes in females after weight gain. We now think that females are more accustomed to weight fluctuations due to pregnancy or the need to store more energy while nursing. For now, that is only a hypothesis, and we are investigating possible mechanisms that provide protection to females.”</p>
<p>One limitation of the study is that it was conducted in mice, and although mouse models are commonly used in scientific research, they may not fully replicate the complexity of human physiology. The researchers also point out that the timing and duration of obesity may play a role in how severely the brain’s reproductive circuits are affected. Chronic, long-term obesity may lead to more pronounced changes in brain function compared to short-term obesity.</p>
<p>Future studies could explore how different lengths of high-fat diet exposure impact reproductive health and whether interventions like diet changes or exercise can reverse the negative effects of obesity on the brain. Further research is needed to explore these differences and understand why females may be more resistant to the reproductive impacts of obesity.</p>
<p>“Our goal is to understand the etiology of disease in order to either prevent it or identify treatments,” Coss said. “Our studies analyzing sex differences may help us identify protective mechanisms in one sex and use it to protect a weaker sex (in obesity case, male).”</p>
<p>The study, “<a href="https://www.jneurosci.org/content/44/28/e0222242024">Obesity Alters POMC and Kisspeptin Neuron Cross Talk Leading to Reduced Luteinizing Hormone in Male Mice</a>,” was authored by Pedro A. Villa, Rebecca E. Ruggiero-Ruff, Bradley B. Jamieson, Rebecca E. Campbell, and Djurdjica Coss.</p></p>
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<td><a href="https://www.psypost.org/new-psychology-study-reveals-we-overestimate-the-consequences-of-declining-social-invitations/" style="font-family:Helvetica, sans-serif; letter-spacing:-1px;margin:0;padding:0 0 2px;font-weight: bold;font-size: 19px;line-height: 20px;color:#222;">New psychology study reveals we overestimate the consequences of declining social invitations</a>
<div style="font-family:Helvetica, sans-serif; text-align:left;color:#999;font-size:11px;font-weight:bold;line-height:15px;">Sep 21st 2024, 06:00</div>
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<p><p>New research published in the <em><a href="https://psycnet.apa.org/record/2024-28543-001?doi=1" target="_blank" rel="noopener">Journal of Personality and Social Psychology</a></em> offers some reassuring insights for anyone who has ever hesitated to decline an invitation to a social event. The study found that people tend to overestimate the negative consequences of saying no to an invitation. Specifically, invitees—those invited to join a social activity—believe that declining an invitation will upset the inviter more than it actually does.</p>
<p>The inspiration for this study came from a very common scenario: the hesitation many people feel when deciding whether to decline a social invitation. Whether it’s a dinner party, a movie night, or a casual hangout, saying no can feel like a difficult social decision. People often worry that declining will make the person who invited them upset or lead to strained relationships. The research team, led by <a href="https://juliangivi.wixsite.com/juliangivi" target="_blank" rel="noopener">Julian Givi</a>, aimed to explore whether these concerns are valid or if they reflect an exaggerated perception of the negative impact.</p>
<p>“I was invited to a wedding that was a bit of a hassle to go to (it was far away and my significant other could not come). I made myself go because I was worried about the couple getting upset. I wondered if I was possibly overblowing just how upset they would be by me not attending,” explained Givi, an associate professor of marketing at West Virginia University.</p>
<p>Previous studies in social psychology have looked at how people interpret others’ actions versus their thoughts, suggesting that individuals often overestimate how much others focus on their behavior rather than on the deliberations behind that behavior. Building on this idea, Givi and his colleagues set out to test whether invitees tend to exaggerate how much an inviter will focus on the rejection rather than the thought process behind it.</p>
<p>The researchers conducted a series of five studies, using both real-life and hypothetical scenarios. In study 1, participants imagined declining or receiving a rejection to an invitation from a friend to attend a museum exhibit. A total of 406 participants were randomly assigned to either the invitee or inviter role and answered questions about their predictions or reactions regarding the negative consequences of the invitation being declined. The researchers then compared the responses of both groups to measure discrepancies between perceived and actual reactions.</p>
<p>Study 2 took a more real-world approach by recruiting 208 couples who were asked to extend and decline invitations to each other for a social activity, such as going to dinner or watching a movie. In this case, one partner served as the inviter, while the other was instructed to decline the invitation, and both partners then independently recorded their emotional responses. This study used real couples to assess the accuracy of invitees’ predictions in an actual social situation, adding ecological validity to the findings.</p>
<p>Study 3 returned to hypothetical scenarios, but this time with an added “observer” condition. Participants were randomly assigned to take the perspective of an invitee, an inviter, or a neutral observer who witnessed the social interaction from an outside perspective. The scenario involved a friend inviting another to a dinner at a restaurant, and the invitee declining the invitation to stay home. By introducing the observer condition, the researchers tested whether outside perspectives aligned more with the invitee’s exaggerated concerns or the inviter’s more realistic responses.</p>
<p>Study 4 used a similar methodology as Study 3 but personalized the experience by having participants name a real-life friend as the inviter. Participants in both the invitee and inviter roles answered questions regarding their expectations of how much the inviter would focus on the rejection itself versus the invitee’s reasons for declining. This study also used mediation analysis to determine whether invitees’ exaggerated concerns about the consequences of saying no were due to their belief that inviters would focus more on the action of declining rather than the deliberations leading to the decision.</p>
<p>Study 5 took a different approach by having participants play both roles, switching between being an invitee and an inviter. In this study, participants first responded to the scenario either as an invitee or an inviter, and then repeated the process from the opposite role. This design allowed researchers to test whether experiencing the inviter role first would lead invitees to adjust their predictions and better understand how inviters actually feel about declines. The comparison between initial and subsequent responses provided insights into whether taking on the inviter’s perspective influenced invitees’ predictions about the consequences of declining an invitation.</p>
<p>The researchers consistently found that invitees significantly overestimated how negatively the inviter would react to the rejection. Invitees tended to think that the person who invited them would be more disappointed, hurt, or angry than the inviter actually was. This pattern emerged across both hypothetical scenarios and real-life invitations. In fact, invitees also believed that declining an invitation would harm the relationship more than it actually did in the eyes of the inviter.</p>
<p>One key finding was that invitees exaggerated the importance of the rejection itself. They assumed that the inviter would focus heavily on the act of declining, rather than understanding that there was likely a thoughtful decision-making process behind it. Inviters, however, reported that they were more understanding of the situation and often considered the invitee’s reasons for declining.</p>
<p>This misperception, the researchers suggested, could be partly explained by a cognitive bias in which people focus more on their own internal thoughts and struggles than on how others might perceive them. In other words, when invitees decline an invitation, they assume that the inviter is focusing solely on the rejection, while in reality, the inviter may be more empathetic to the reasons behind the decline.</p>
<p>“It is OK to say no to invitations from time to time,” Givi told PsyPost. “Inviters are more understanding than we might expect. Of course, I don’t recommend always saying no, because repeated declines could lead them to be upset and/or you to not get invited any more.”</p>
<p>Although the study provides valuable insights into the social dynamics of declining invitations, there are a few limitations to consider. First, the research largely focused on small, everyday social events like dinners or casual outings. The findings might not extend to larger or more significant events, such as weddings or milestone celebrations, where the social stakes may be higher, and the emotional reactions of inviters might be stronger. Further research is needed to explore how declining invitations to these kinds of events might differ from more casual ones.</p>
<p>Another potential avenue for future research could explore whether the specific reason for declining an invitation affects the inviter’s reaction. In this study, the reason for declining was held constant—participants were instructed to say they simply wanted to stay home and relax. But in real life, people decline invitations for many reasons, such as having a prior commitment or lacking time or resources.</p>
<p>“The psychology involved with extending and receiving invitations has not been explored very much, so I have a few ongoing projects that looks at this topic,” Givi said.</p>
<p>The study, “<a href="https://psycnet.apa.org/doiLanding?doi=10.1037%2Fpspi0000443" target="_blank" rel="noopener">Saying No: The Negative Ramifications From Invitation Declines Are Less Severe Than We Think</a>,” was authored by Julian Givi and Colleen P. Kirk.</p></p>
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<td><a href="https://www.psypost.org/robots-eye-contact-elicits-human-like-responses-in-infants/" style="font-family:Helvetica, sans-serif; letter-spacing:-1px;margin:0;padding:0 0 2px;font-weight: bold;font-size: 19px;line-height: 20px;color:#222;">Robots’ eye contact elicits human-like responses in infants</a>
<div style="font-family:Helvetica, sans-serif; text-align:left;color:#999;font-size:11px;font-weight:bold;line-height:15px;">Sep 20th 2024, 14:00</div>
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<p><p>Researchers recently published a study in the journal <a href="https://doi.org/10.1016/j.biopsycho.2024.108858"><em>Biological Psychology</em></a> investigating how infants respond to eye contact from both humans and humanoid robots. The study found that infants, even at just 6 to 8 months old, recognize the significance of eye contact, not only from human faces but also from robots with human-like features.</p>
<p>The ability to interpret eye contact is a critical part of social development. From a very young age, infants are already attuned to the eyes of those around them. Eye contact can signal social intentions, such as a desire to communicate or form an emotional connection. Past research has shown that even newborns prefer faces with direct gazes over faces with averted gazes, suggesting that eye contact plays a role in shaping early social interactions.</p>
<p>However, much of the research on infants’ response to eye contact has focused on interactions with humans. As humanoid robots become more prevalent in settings like caregiving and education, it raises an important question: Do infants view eye contact from robots as socially meaningful in the same way they do with humans?</p>
<p>“Humanoid robots are becoming increasingly common in social environments, and people are suddenly expected to engage in social interactions with these artificial agents. We are interested in how the human brain understands the ‘sociality’ of artificial humanoid robots,” said study author Samuli Linnunsalo, a doctoral researcher in Tampere University and member of the <a href="https://research.tuni.fi/hiplab/" target="_blank" rel="noopener">Human Information Processing Laboratory</a>.</p>
<p>“We believe that, to fully explore people’s instinctive interpretations of humanoid robots’ sociality, it is necessary to use physiological measures to investigate their responses to robots’ nonverbal social cues, such as eye contact. After finding initial evidence that adult humans’ psychophysiological responses to eye contact with a humanoid robot were similar to their responses to eye contact with a human, we sought to investigate whether young infants react similarly to a humanoid robot’s and a human’s eye gaze. This was particularly interesting to us, because infants do not have knowledge of the humanoid robots’ purpose as social interaction partners, nor do they understand that people are expected to treat humanoid robots as social agents.”</p>
<p>The study involved 114 infants, aged between 6 to 8 months. The researchers invited the infants to a laboratory where they were exposed to three different types of stimuli: a human, a humanoid robot called Nao, and a non-human object, in this case, a vase. The researchers used live stimuli rather than videos or images to make the experience more realistic for the infants.</p>
<p>Each of the human and robot models was presented to the infant either looking directly at them (direct gaze) or looking away (averted gaze). To ensure the infants were engaged, the researchers used a carefully controlled environment with an interactive introduction for both the human and the robot. The robot would introduce itself, mimicking natural social gestures like nodding and hand movements, while the vase served as a non-interactive control object.</p>
<p>The infants’ reactions were recorded using several different measures. Researchers tracked how long the infants looked at the different stimuli, measured their heart rate to assess attention, and used electrodes to capture changes in facial muscles to gauge emotional responses. These muscle measures focused on two areas of the face: the cheek muscles associated with smiling and the eyebrow muscles often linked to frowning or concentration.</p>
<p>The researchers found that the infants looked longer at both the human and the robot than they did at the vase, which suggests that they found the human and robot more socially engaging than the inanimate object. However, their looking times did not differ between direct and averted gazes from either the human or the robot. This suggests that while the infants were interested in both, the direction of the gaze didn’t capture their attention for longer durations in this context.</p>
<p>In terms of heart rate, which can reflect how much attention someone is paying, the infants’ heart rates slowed down more when they saw averted gazes compared to direct gazes. This suggests that infants may have been paying closer attention to the averted gaze, possibly because it signals an opportunity for joint attention—learning where the other person (or robot) is looking. This might represent an early developmental step toward joint attention skills, which are key in social development.</p>
<p>“We were surprised to find that infants at this age (6–8 months) attended more intensively to the averted gaze of a humanoid robot or a human, compared to direct gaze (eye contact),” Linnunsalo told PsyPost. “Previous research has shown that newborns, children, and adults orient their attention more strongly toward direct gaze than averted gaze. We interpreted this finding as reflecting the development of joint attention skills in 6–8-month-old infants’ (i.e., looking where the other person/robot is looking), which may require heightened interest in averted gaze.”</p>
<p>Facial muscle activity provided another layer of insight. The infants’ cheek muscles—associated with smiling—became more active in response to direct eye contact from both the human and the robot. Meanwhile, their eyebrow muscles, linked to frowning or concentration, showed more activity when the gaze was averted. This pattern suggests that eye contact, whether from a human or a robot, prompted more positive or affiliative facial expressions in the infants.</p>
<p>“Infants responded to a humanoid robot’s eye gaze similarly to how they responded to the eye gaze of another human,” Linnunsalo said. “Specifically, eye contact with either a humanoid robot or a human led to greater activity in the smiling muscles compared to viewing averted eye gaze. On the other hand, a humanoid robot’s or a human’s averted eye gaze captured infants’ attention more intensely than eye contact. These results suggest that, even in infancy, the human brain may interpret humanoid robots’ eye gaze signals as if the robots were human.”</p>
<p>Interestingly, skin conductance, which measures emotional arousal, did not show significant differences between direct and averted gazes for either the human or the robot. This result suggests that while infants recognized the social significance of eye contact, it may not yet produce strong emotional arousal at this early age. Emotional responses to eye contact, as seen in adults, might develop later in childhood as infants gain more experience with social interactions.</p>
<p>While the study offers valuable insights, it has a few limitations. One limitation is the use of a vase as a control object. “Since the control stimulus did not have eyes, we cannot rule out the possibility that infants’ responses to the humanoid robot’s eye gaze were driven primarily by its eyes, independent of its humanlike, social behavior,” Linnunsalo noted. “In other words, we do not know how much simpler the humanoid robot could have been in appearance or behavior for its eye gaze to still elicit these responses.”</p>
<p>Future research could examine how infants’ responses to humanoid robots evolve as they grow older. For instance, do children continue to interpret robots as social agents, or do they begin to differentiate between robots and humans as they develop more complex social understanding? Additionally, researchers could explore more interactive robots that can engage in more dynamic social behaviors, such as following the infant’s gaze or responding to the infant’s expressions.</p>
<p>“Our long-term goal for this line of research is to understand the human social brain and the extent to which it adapts to social interactions with artificial agents,” Linnunsalo said. “We would like to express our gratitude to the parents who brought their infants to the laboratory and managed to keep them relatively still during the experiment.”</p>
<p>The study, “<a href="https://www.sciencedirect.com/science/article/pii/S0301051124001170" target="_blank" rel="noopener">Infants’ psychophysiological responses to eye contact with a human and with a humanoid robot</a>,” was authored by Samuli Linnunsalo, Santeri Yrttiaho, Chiara Turati, Ermanno Quadrelli, Mikko J. Peltola, and Jari K. Hietanen.</p></p>
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<td><a href="https://www.psypost.org/research-shows-diabetes-drug-could-reduce-dementia-risk-heres-how-the-two-diseases-may-be-linked/" style="font-family:Helvetica, sans-serif; letter-spacing:-1px;margin:0;padding:0 0 2px;font-weight: bold;font-size: 19px;line-height: 20px;color:#222;">Research shows diabetes drug could reduce dementia risk. Here’s how the two diseases may be linked</a>
<div style="font-family:Helvetica, sans-serif; text-align:left;color:#999;font-size:11px;font-weight:bold;line-height:15px;">Sep 20th 2024, 12:00</div>
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<p><p>A Korean study published recently suggests people with type 2 diabetes who are prescribed a particular class of drug might be at a significantly <a href="https://www.bmj.com/content/386/bmj-2024-079475">lower risk of dementia</a>.</p>
<p>The researchers compared the health outcomes of more than 110,000 people aged 40–69 with type 2 diabetes who had been prescribed a type of drug called SGLT-2 inhibitors with those of another 110,000 patients taking a different class of drug, DPP-4 inhibitors. They followed participants for an average of 670 days.</p>
<p>The researchers found that, after accounting for potential confounding factors, those taking an SGLT-2 inhibitor were 35% less likely to develop dementia.</p>
<p>Diabetes is recognised as a <a href="https://www.alzheimers.org.uk/about-dementia/managing-the-risk-of-dementia/reduce-your-risk-of-dementia/diabetes">risk factor for dementia</a>. So it’s not entirely surprising that treating diabetes could reduce the risk of dementia. But why would one drug cut the risk more than another? And how are diabetes and dementia linked anyway?</p>
<h2>Diabetes and dementia</h2>
<p>Insulin is a hormone produced by the pancreas. Its job is to move glucose (sugar) from our bloodstream into our cells, where it serves as a source of energy. Type 2 diabetes arises when our pancreas <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/diabetes">fails to produce</a> enough insulin, or our cells develop a resistance to insulin.</p>
<p>Dementia is caused by changes in the brain and encompasses <a href="https://www.dementia.org.au/about-dementia">several conditions</a> that affect memory, thinking, mood, and our ability to perform daily tasks.</p>
<p>Diabetes has long been recognised as a risk factor for both Alzheimer’s disease and <a href="https://www.mayoclinic.org/diseases-conditions/vascular-dementia/symptoms-causes/syc-20378793">vascular dementia</a>, the two most common forms of dementia. Both are characterised by cognitive decline caused by disease of blood vessels in the brain.</p>
<p>We don’t fully understand why diabetes and dementia are linked in this way, but there <a href="https://www.alz.org/media/documents/alzheimers-dementia-diabetes-cognitive-decline-ts.pdf">a few possible reasons</a>.</p>
<p>For example, diabetes increases the risk of heart disease and stroke, which damage the heart and blood vessels. When blood vessels in the brain are damaged, this may contribute to cognitive decline.</p>
<p>Also, high blood sugar levels cause inflammation, which may damage brain cells and contribute to the development of dementia.</p>
<h2>Treating diabetes could mitigate the increased risk</h2>
<p>Better control of blood sugar levels in diabetes helps protect blood vessels and <a href="https://www.alz.org/media/documents/alzheimers-dementia-diabetes-cognitive-decline-ts.pdf">reduces inflammation</a> in the brain.</p>
<p>Diabetes may be controlled initially with lifestyle modifications such as diet and exercise, but management may also include medications, such as those taken by participants in the <a href="https://www.bmj.com/content/386/bmj-2024-079475">Korean study</a>.</p>
<p>Patients taking either type of drug had comparable blood glucose control. But why did one reduce the risk of people developing dementia compared to the other?</p>
<p>SGLT-2 inhibitors (which stands for sodium-glucose transport protein 2) lower blood glucose by increasing its removal by the kidneys. These drugs are known to have <a href="https://www.tandfonline.com/doi/full/10.2147/DMSO.S233538">positive effects</a> on other areas of health too, including improving blood pressure, promoting weight loss, and reducing inflammation and oxidative stress (a type of damage to our cells).</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4887143/">Obesity</a> and <a href="https://www.alzheimers.org.uk/about-dementia/managing-the-risk-of-dementia/reduce-your-risk-of-dementia/high-blood-pressure">high blood pressure</a> are themselves risk factors for vascular and Alzheimer’s-type dementia, so it may well be that these effects of the SGLT-2 inhibitors lower dementia risk to a greater degree than what could be expected by better blood glucose control alone.</p>
<h2>Prevention versus treatment</h2>
<p>It’s important to emphasise that the benefit of a drug reducing the risk of developing a disease is quite separate from any suggestion that the drug might be useful in treating that disease. The best way to reduce your risk of lung cancer, for example, is to stop smoking. Once you have lung cancer, however, stopping smoking is insufficient to treat it.</p>
<p>Having said this, because of the evidence linking diabetes and dementia, certain diabetes drugs have previously been investigated as treatments for Alzheimer’s disease. And they have been shown to provide a degree of <a href="https://dom-pubs.onlinelibrary.wiley.com/doi/abs/10.1111/dom.13373">benefit to cognition</a>.</p>
<p>Semaglutide, better known by the trade name Ozempic, is a member of yet another class of diabetes drugs (called GLP1 receptor agonists). Semaglutide is currently being studied as a treatment for early Alzheimer’s disease in two clinical trials involving <a href="https://www.neurology.org/doi/abs/10.1212/WNL.0000000000205079">more than 3,500 patients</a>.</p>
<p>These studies were themselves sparked by observations during clinical trials of semaglutide for people with diabetes, which showed <a href="https://alz-journals.onlinelibrary.wiley.com/doi/full/10.1002/alz.042909">lower rates of dementia</a> in those who took the drug compared to those who took a placebo.</p>
<p>Similar to the SGLT-2 drugs, the GLP-1 class of drugs is known to reduce <a href="https://www.sciencedirect.com/science/article/pii/S1043661822004960">inflammation in the brain</a>. GLP-1 drugs also appear to reduce chemical reactions that lead to an abnormal form of a protein called Tau, one of the <a href="https://pubmed.ncbi.nlm.nih.gov/26746341/">pathological hallmarks of Alzheimer’s disease</a>.</p>
<h2>What next?</h2>
<p>As our knowledge of the mechanisms underlying Alzheimer’s disease and other forms of dementia continues to grow, so will advances in treatment.</p>
<p>It’s unlikely that a single drug will be the answer to Alzheimer’s disease. Cancer treatments have evolved to the point where the use of “drug cocktails”, or a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7915944/">combination of drugs</a>, is now routine.</p>
<p>One possible future for these diabetes drugs is that we may see them used as part of a range of treatments to combat the ravages of dementia or, indeed, help prevent it, even in people without diabetes. But we need more research before we get to this point.<!-- Below is The Conversation's page counter tag. Please DO NOT REMOVE. --><img decoding="async" src="https://counter.theconversation.com/content/237760/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1"><!-- End of code. If you don't see any code above, please get new code from the Advanced tab after you click the republish button. The page counter does not collect any personal data. More info: https://theconversation.com/republishing-guidelines --></p>
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<p><em>This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/research-shows-diabetes-drug-could-reduce-dementia-risk-heres-how-the-two-diseases-may-be-linked-237760">original article</a>.</em></p></p>
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<p><strong>Forwarded by:<br />
Michael Reeder LCPC<br />
Baltimore, MD</strong></p>
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