A new USC study shows teens with higher blood levels of per- and polyfluoroalkyl substances (PFAS) measured before bariatric surgery had smaller improvements in blood sugar over five years, including fasting glucose and hemoglobin A1c (HbA1c), which measures average blood sugar levels over the past 60-90 days. Blood sugar is a key marker of the surgery’s success—and the differences were large enough that the metabolic benefits of the surgery could fade within a decade. The results, published in the journal Environmental Endocrinology, suggest that PFAS exposure may help explain why metabolic outcomes differ among patients. Patient data for the study came from the Teen Longitudinal Assessment of Bariatric Surgery (Teen-LABS), which tracks outcomes among adolescents who have undergone the weight loss procedure. In 186 teens, aged 19 or younger, the researchers measured levels of eight types of PFAS before patients had surgery. After surgery, the researchers tracked each patient’s metabolic health at six months, 12 months, 36 months and five years. To measure short- and long-term blood sugar levels, they collected data on fasting glucose and HbA1c. They also measured insulin and estimated insulin resistance, or how hard the body has to work to keep blood sugar under control. Overall, most Teen-LABS patients had significant improvements in metabolic health after surgery. But teens with higher exposure to all eight PFAS together showed a smaller improvement in long-term blood sugar, with their HbA1c rising, on average, 0.27 percentage points three years after surgery. (For context, a normal HbA1c is under 5.7%, so this increase is considerable.) One PFAS in particular, perfluorohexanesulfonic acid (PFHxS), had an outsized impact. Teens with higher PFHxS exposure before surgery had average annual increases of 0.15 percentage points in HbA1c, a rate that could move someone from normal blood sugar to prediabetes—or from prediabetes to type 2 diabetes—within a few years. PFHxS was also linked to rising fasting glucose, about one milligram per deciliter (mg/dL) per year. At that rate, a patient who initially improved by 10 mg/dL after surgery could see those gains reversedwithin a decade.

A new study from Rice University and Johannes Gutenberg University Mainz finds that older adults with age-related macular degeneration (AMD) can judge the arrival time of approaching vehicles more accurately than expected—despite impaired central vision. Using a first-of-its-kind virtual reality system with realistic vehicle sounds, researchers examined whether adults with AMD rely more on hearing when estimating when a car will reach them. Instead, participants with vision loss continued to use their remaining visual information and performed similarly to adults with normal vision, although they showed slightly greater reliance on less accurate visual and auditory cues. The findings offer new insight into how people with central vision loss make split-second mobility decisions, such as crossing a street, and may help inform future rehabilitation, safety training and assistive technologies for individuals with visual impairments.

Higher nighttime temperatures are linked to shorter sleep times and lower sleep quality, especially for people with chronic health conditions, lower socioeconomic status, or those living on the West Coast, according to a new USC study. Researchers estimate that by 2099, people could lose up to 24 hours of sleep each year due to heat, highlighting the potential impact of climate change on sleep health. The researchers obtained data from 14,232 U.S. adults in the All of Us Research Program that was collected between 2010 and 2022. In total, the researchers analyzed more than 12 million nights of sleep, looking at how long people slept and how easily they fell asleep. They also examined 8 million nights of data on sleep stages and how often sleep was interrupted. Finally, they used location and meteorological data to find out whether sleep patterns were linked to changing temperatures. They found that a 10-degree Celsius increase in daytime temperature was associated with 2.19 minutes of lost sleep, while a 10-degree nighttime temperature increase was associated with a loss of 2.63 minutes. The effects were greater among females, people of Hispanic ethnicity, people with chronic diseases, and those with a lower socioeconomic status. In addition to shorter sleep times, rising temperatures were also associated with more disrupted sleep throughout the night and more time spent awake in bed.

A discovery by FIU researchers could help forensic investigators close the gap on estimating time of death. Often, death investigations rely on maggots — the larvae of blow flies that are among the first insects to colonize a body after death — to estimate how long a person has been dead. The presence of eggs or the sizes of the maggots are indicators of time since death. Yet, there is a stage in their development, where the maggot’s physical form changes very little, which limits the precision of time of death estimates. While changes may not be visible on a maggot’s outside, their genes can still tell a story.