Medical Bulletin 19/ July/ 2024

Inconsistent Sleep Patterns Linked to Increased Type 2 Diabetes Risk: Study

Regular sleep could play a crucial role in preventing type 2 diabetes, according to a recent study conducted by researchers at Brigham and Women’s Hospital. The study highlighted that individuals with irregular sleep patterns have a significantly higher risk of developing type 2 diabetes compared to those with more consistent sleep schedules.

The study was published in the journal Diabetes Care.

The research team monitored sleep patterns over the course of seven nights and subsequently tracked the health of participants for more than seven years. Their findings revealed that those with the most irregular sleep durations had a 34% higher risk of developing diabetes compared to their counterparts who maintained consistent sleep schedules.

Type 2 diabetes is a major global health concern, affecting nearly half a billion people worldwide. It ranks among the top 10 leading causes of death and disability, with projections indicating that the number of affected individuals will more than double to 1.3 billion by 2050.

To explore the potential link between sleep and type 2 diabetes, the researchers analysed accelerometery data from over 84,000 participants in the UK Biobank Study. The participants, who had an average age of 62 years and were initially free of diabetes, wore accelerometers — devices akin to watches that monitor movement — for seven nights. Their health was then tracked for approximately 7.5 years, primarily through medical records.

The study found a strong association between irregular sleep duration and increased diabetes risk. Irregular sleep was defined as a variation in day-to-day sleep duration by more than 60 minutes on average. Even after adjusting for various risk factors such as lifestyle, comorbidities, family history of diabetes, and obesity indicators, the data showed that participants with irregular sleep had a 34% higher risk of developing diabetes compared to those with regular sleep patterns.

“Our study identified a modifiable lifestyle factor that can help lower the risk of developing type 2 diabetes. Our findings underscore the importance of consistent sleep patterns as a strategy to reduce type 2 diabetes,” said Sina Kianersi, a research fellow in the Channing Division of Network Medicine at the Brigham.

Reference: Sina Kianersi, Heming Wang, Tamar Sofer, Raymond Noordam, Andrew Phillips, Martin K. Rutter, Susan Redline, Tianyi Huang; Association Between Accelerometer-Measured Irregular Sleep Duration and Type 2 Diabetes Risk: A Prospective Cohort Study in the UK Biobank. Diabetes Care 2024; dc240213. https://doi.org/10.2337/dc24-0213

Vaccines May Significantly Lower Long Covid Risk: Study

A large study recently published in the New England Journal of Medicine has provided some of the strongest evidence to date that vaccines significantly reduce the risk of developing long Covid. The study, which focused on people infected during the first two years of the pandemic, found a substantially lower percentage of long Covid cases among vaccinated individuals compared to their unvaccinated counterparts.

Medical experts have long suggested that vaccines can lower the risk of long Covid by preventing severe illness during the infection period. Individuals who experience severe infections are more likely to develop long-term symptoms. However, the study highlighted that even those with mild infections could develop long Covid, and vaccination, while significantly reducing the risk, did not entirely eliminate the possibility of developing the condition.

The study analysed medical records from the Department of Veterans Affairs health system, involving nearly 450,000 Covid-19 patients and approximately 4.7 million uninfected individuals from March 1, 2020, to January 31, 2022.

Researchers estimated the percentage of Covid-19 patients who experienced long Covid one year after infection. Among those vaccinated and infected during the latest period of the study (mid-December 2021 to January 2022), the rate of long Covid was 3.5 percent, compared to 7.8 percent for unvaccinated patients infected during the same period. This period included the emergence of the Delta and Omicron variants.

The results showed that the rate of long Covid among unvaccinated individuals infected between June 19 and December 18, 2021, during the Delta wave, was 9.5 percent. This rate decreased to 7.8 percent for those infected during the Omicron wave (December 19, 2021, to January 31, 2022). Among vaccinated individuals, the rates were significantly lower: 5.3 percent during the Delta period and 3.5 percent during the Omicron period. The researchers attributed about 72 percent of the decrease in long Covid cases to vaccination.

Although the study did not cover periods beyond January 2022, a recent survey by the Centers for Disease Control and Prevention (CDC) reported that about 5.3 percent of adults, or approximately 13.7 million people, currently have long Covid.

Reference: Clifford J. Rosen, Viral Variants, Vaccinations, and Long Covid — New Insights, New England Journal of Medicine, 0, 0, (undefined). /doi/full/10.1056/NEJMe2407575

Magic Mushrooms Lead to Weeks-Long Brain Desynchronization, Study Finds

Once criticized for their psychedelic properties, magic mushrooms are now garnering attention for their potential therapeutic benefits in treating a variety of mental health issues. Despite this growing interest, the neurological effects of psilocybin, the psychoactive compound in these mushrooms, remain largely unexplored. This knowledge gap makes it challenging to predict how psilocybin could ultimately be used in medical treatments.

A recent study led researchers from Washington University School of Medicine, sought to bridge this gap by examining brain changes in seven healthy adults before, during, and after taking a high dose of psilocybin. The findings, published in Nature, identified disruptions in brain connectivity that persisted for weeks in some areas.

The research aimed to understand how psilocybin's biochemical effects translate into large-scale behavioural changes that could either benefit or hinder individuals with different psychological needs.

Psilocybin mimics serotonin's affinity for the 5-HT2A receptor, leading to well-documented effects such as euphoria and altered perceptions of self, time, space, sound, and colour. Animal studies have shown that activating these receptors can lead to long-lasting effects by promoting neural plasticity – the brain's ability to form new connections and adapt. This plasticity makes psilocybin a promising candidate for treating stubborn psychological conditions. However, whether these effects translate to humans was unclear.

In the study, researchers used functional magnetic resonance imaging (fMRI) scans to monitor volunteers before, immediately after, and 21 days following a 25-milligram dose of psilocybin. For comparison, the subjects also received a 40-milligram dose of the stimulant methylphenidate on separate occasions, with similar scans taken.

The results showed significant disruptions in functional connectivity across the brain's cortex after the psilocybin dose. Major changes were also observed in the default mode network (DMN), a group of brain regions most active when a person is awake but not engaged in a specific task. Previous studies in rats suggested that psilocybin causes nerve cells to fall out of sync, temporarily erasing the patterns that underlie our sense of self.

Interestingly, performing a simple auditory-visual matching task during scans after the psilocybin dose seemed to stabilize the DMN, reducing disruption severity. Three weeks later, the cortex had mostly returned to pre-dose synchronization. However, the anterior hippocampus, a region involved in perception and memory, continued to show persistent functional changes.

“Understanding the relationship between psilocybin's pharmacology and its effects within a neurological framework could pave the way for new treatments for depression, post-traumatic stress, and other conditions. While we are still far from seeing psilocybin prescribed in clinical settings, studies like this bring us closer to unlocking the therapeutic potential of this fascinating compound,” said Joshua Siegel, psychiatrist at Washington University School of Medicine.

Reference: Siegel, J.S., Subramanian, S., Perry, D. et al. Psilocybin desynchronizes the human brain. Nature (2024). https://doi.org/10.1038/s41586-024-07624-5