Diabetes and weight loss treatments such as Ozempic and Wegovy, known as GLP-1 agonists, could significantly reduce the risk of developing any type of dementia, according to a meta-analysis of 26 clinical trials with more than 160,000 participants.

The treatments, which include medications like semaglutide, liraglutide and exenatide, have been linked to a slightly reduced dementia risk before, but this was based on observational studies looking at health records.

Now, at the University of Galway in Ireland and her colleagues have combined the results of randomised trials where a range of GLP-1 drugs were given to people with type 2 diabetes who hadn’t yet been diagnosed with dementia or cognitive impairment, tested against a placebo. They found that taking these drugs seemed to significantly reduce the risk of developing dementia or cognitive impairment during the trials’ minimum six-month follow-up periods.

“The gold standard would be one large, randomised trial to answer this question, but this definitely adds another stream of evidence [to past studies],” says at Washington University School of Medicine in St. Louis, Missouri, who wasn’t involved in this research.

Diabetes may be a , so it has been suggested that just controlling blood sugar levels produces this protective effect. For instance, a by at the University of Florida and her colleagues suggests that a class of diabetes drugs called SGLT2 inhibitors, which lower blood sugar levels by helping the kidneys remove excess glucose, may reduce the risk of Alzheimer’s disease or related kinds of dementia, based on people’s health records.

But in Reddin and her team’s placebo-controlled analysis, SGLT2 inhibitors weren’t linked to a reduced dementia risk, which suggests that the protective effects of GLP-1 drugs go beyond just blood sugar control.

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Although the exact mechanism is unclear, these drugs have been linked to reduced inflammation, with increasingly being recognised as a cause of dementia. By reducing chronic inflammation, they may , says Reddin.

GLP-1 drugs may also protect against , such as in the arteries and , which could otherwise cause dementia.

“All roads seem to be leading to Rome. We can see from multiple observational studies and now an analysis of placebo-controlled studies that these medications have this [anti-dementia] effect,” says Al-Aly.

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Al-Aly stresses that we aren’t yet at a place where someone who is at an increased risk of developing dementia would be prescribed GLP-1 drugs to lower their odds. But he also says doctors may consider offering these medications over other glucose-lowering ones to people with type 2 diabetes who are also at an increased risk of cognitive decline, for example if they had a family history of the condition. “This research will increase a physician’s propensity for prescribing these medications,” he says.

Reddin notes that the analysis’ minimum six-month follow-up period was relatively short, and says “large trials should be conducted to specifically study the effect of glucose-lowering therapy on dementia and cognitive decline”. Two clinical trials investigating semaglutide as a therapy for early Alzheimer’s disease are expected to conclude this year.

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Inflammation

Longevity

The unexpected ways your skin impacts your health and longevity

Looking after your skin isn't just a vanity project, with growing evidence that damage to the skin can drive ageing, inflammation and even cognitive decline

Wearing foundation while exercising may affect the health of the skin by changing its pore size and the subsequent release of sebum, which plays a role in keeping it healthy.

at Texas A&M University, San Antonio, and his colleagues recruited 43 college students, 20 men and 23 women. The participants first washed their faces with a cleanser. The researchers then measured skin variables on different areas of their faces, including pore size and sebum production.

Next, a single layer of foundation was applied to all the participants’ faces, either their foreheads or cheeks, depending on which they preferred.

They then did a moderate 20-minute workout, consisting of running on a treadmill for 5 minutes at 3 miles per hour (mph), for 10 minutes at 4 mph and for 5 minutes at 5 mph.

After the workout, the researchers repeated the various skin measurements, finding that sebum was reduced on the areas with foundation compared with those without make-up.

“This is a gleaming example of the deleterious effects of make-up use during exercise,” the researchers wrote in their paper. “In this study, make-up use clogged the pores, which led to a negative sebum score.” The optimal amount of sebum is unclear, with too much being linked to acne and too little causing skin irritation.

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The size of the participants’ pores also significantly increased in the areas without foundation, while there was no meaningful change to those in the made-up areas. This suggests that the foundation may have restricted pores from naturally enlarging during exercise, preventing the release of sebum and sweat, which moisturises and cools skin. The researchers didn’t assess whether these changes were linked to any skin issues.

Wearing foundation while exercising may not have a big effect on most people who do relatively short workouts, but “we don’t know the impact for endurance-type athletes”, says Lee. The team now hopes to investigate the effects during longer exercise routines.

at Weill Cornell Medicine in New York says that the study’s split-face design is a good approach, but our skin’s characteristics vary on different parts of our face, complicating comparison. In addition, skin on the nose and around the mouth and eyes differs in thickness compared with that on the forehead or cheeks, so ideally these areas should have also been studied, she says.

Exposing immobile sperm to ultrasound waves gets them moving, a lab study has shown. Sperm that don’t move properly are a key cause of infertility, as it is harder for them to reach the egg. With further research, this technique could help improve the success rate of in vitro fertilisation (IVF).

Previous research has suggested that . However, this work didn’t involve isolating the sperm to assess which individual cells benefited, which could then point doctors towards the optimal ones to use in fertility treatments.

In the latest research, and his colleagues at Monash University in Melbourne, Australia, separated 50 semen samples into three groups according to their sperm motility: rapid, slow and immotile, based on guidelines that assess swimming velocity.

After separating the individual sperm cells from the semen samples, the researchers measured the motility of the cells before and after they were exposed to ultrasonic sound waves at a power of 800 milliwatts and a frequency of 40 megahertz.

Following 20 seconds of ultrasound exposure, 59 per cent of the immotile sperm became slow moving, with some even starting to swim rapidly. The change in sperm motility peaked at a 266 per cent increase.

Overall, immotile sperm made up 36 per cent of the samples at the start of the study, declining to just 10 per cent post-treatment. It is unclear how long the increase in movement lasted.

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The researchers think exposure to ultrasound improves any dysfunction in the sperm’s mitochondria, the power stations of cells, which contributes to their improved motility.

The approach may one day increase the success of IVF, which requires motile sperm for conception, potentially avoiding the need for multiple costly rounds of the procedure.

But first, Vafaie says a research group would need to test the effectiveness of the approach on sperm from those who are experiencing infertility due to poor sperm mobility specifically. żěè¶ĚĘÓƵs also need to assess whether it is safe to create embryos from ultrasound-exposed sperm, he says.