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Too Much Light at Night Linked to Higher Alzheimer's Risk

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Friday, September 6, 2024

By Dennis Thompson HealthDay ReporterFRIDAY, Sept. 6, 2024 (HealthDay News) -- People who live in areas with more nighttime light pollution could be at increased risk of Alzheimer’s disease, particularly those in middle age, a new study says.Nightly light pollution is more strongly linked to Alzheimer’s disease in people 65 and older than other known risk factors like alcohol abuse, kidney disease, depression and obesity, researchers reported Sept. 5 in the journal Frontiers in Neuroscience.And light exposure poses an even greater risk to the brains of people younger than 65.High nighttime light intensity was the top risk factor for early-onset Alzheimer’s in that age group.“We show that in the U.S. there is a positive association between Alzheimer’s disease prevalence and exposure to light at night, particularly in those under the age of 65,” said lead researcher Robin Voigt-Zuwala, an associate professor at Rush University Medical Center in Chicago.“Nightly light pollution -- a modifiable environmental factor -- may be an important risk factor for Alzheimer’s disease,” Voigt-Zuwala added in a university news release.For the study, researchers analyzed light pollution maps for the 48 continental states, comparing them to national data about Alzheimer’s disease incidence and known risk factors for the degenerative brain disease.Light pollution appears to be an Alzheimer’s risk factor for seniors, but it is not as strong an influence as other factors like diabetes, high blood pressure and stroke, results show.But no other risk factor outpaced light pollution for those younger than 65, researchers found.The results suggest that younger people might be particularly sensitive to the effects of light exposure at night, although it’s not clear why, researchers said.Genetics that increase a person’s risk for early-onset Alzheimer’s “impact the response to biological stressors, which could account for increased vulnerability to the effects of nighttime light exposure,” Voigt-Zuwala theorized. “Additionally, younger people are more likely to live in urban areas and have lifestyles that may increase exposure to light at night.”Given these findings, people might want to limit their exposure to bright lights at night, the researchers said.“Easy-to-implement changes include using blackout curtains or sleeping with eye masks,” Voigt-Zuwala said. “This is useful especially for those living in areas with high light pollution.”Light exposure inside a home could be just as important, the researchers added. People should limit their exposure to blue light, which can affect sleep, and install dimmers in their home.SOURCE: Rush University Medical Center, news release, Sept. 6, 2024Copyright © 2024 HealthDay. All rights reserved.

By Dennis Thompson HealthDay ReporterFRIDAY, Sept. 6, 2024 (HealthDay News) -- People who live in areas with more nighttime light pollution could...

By Dennis Thompson HealthDay Reporter

FRIDAY, Sept. 6, 2024 (HealthDay News) -- People who live in areas with more nighttime light pollution could be at increased risk of Alzheimer’s disease, particularly those in middle age, a new study says.

Nightly light pollution is more strongly linked to Alzheimer’s disease in people 65 and older than other known risk factors like alcohol abuse, kidney disease, depression and obesity, researchers reported Sept. 5 in the journal Frontiers in Neuroscience.

And light exposure poses an even greater risk to the brains of people younger than 65.

High nighttime light intensity was the top risk factor for early-onset Alzheimer’s in that age group.

“We show that in the U.S. there is a positive association between Alzheimer’s disease prevalence and exposure to light at night, particularly in those under the age of 65,” said lead researcher Robin Voigt-Zuwala, an associate professor at Rush University Medical Center in Chicago.

“Nightly light pollution -- a modifiable environmental factor -- may be an important risk factor for Alzheimer’s disease,” Voigt-Zuwala added in a university news release.

For the study, researchers analyzed light pollution maps for the 48 continental states, comparing them to national data about Alzheimer’s disease incidence and known risk factors for the degenerative brain disease.

Light pollution appears to be an Alzheimer’s risk factor for seniors, but it is not as strong an influence as other factors like diabetes, high blood pressure and stroke, results show.

But no other risk factor outpaced light pollution for those younger than 65, researchers found.

The results suggest that younger people might be particularly sensitive to the effects of light exposure at night, although it’s not clear why, researchers said.

Genetics that increase a person’s risk for early-onset Alzheimer’s “impact the response to biological stressors, which could account for increased vulnerability to the effects of nighttime light exposure,” Voigt-Zuwala theorized. “Additionally, younger people are more likely to live in urban areas and have lifestyles that may increase exposure to light at night.”

Given these findings, people might want to limit their exposure to bright lights at night, the researchers said.

“Easy-to-implement changes include using blackout curtains or sleeping with eye masks,” Voigt-Zuwala said. “This is useful especially for those living in areas with high light pollution.”

Light exposure inside a home could be just as important, the researchers added. People should limit their exposure to blue light, which can affect sleep, and install dimmers in their home.

SOURCE: Rush University Medical Center, news release, Sept. 6, 2024

Copyright © 2024 HealthDay. All rights reserved.

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Check Your City: Air Pollution Linked to Slower Marathon Times

By Deanna Neff HealthDay ReporterTHURSDAY, Nov. 6, 2025 (HealthDay News) — Does the city you run in make a difference? Researchers say yes, it...

By Deanna Neff HealthDay ReporterTHURSDAY, Nov. 6, 2025 (HealthDay News) — Does the city you run in make a difference? Researchers say yes, it does.When marathon runners hit the wall or fall behind their goal pace, they often blame fatigue, weather or nutrition. However, a study from Brown University published in Sports Medicine suggests a less obvious, environmental culprit: air pollution.Researchers analyzed a dataset of 2.6 million marathon finish times from major U.S. races, including those in Boston, New York City and Los Angeles, spanning 17 years and matched it to estimated pollution levels from weather stations. They found a direct link between slower average finish times and higher concentrations of fine particulate matter known as PM2.5.The data also showed that the fastest runners were more affected by this effect.PM2.5 refers to tiny pollutants smaller than 2.5 micrometers in diameter. These particles are often the focus of air-quality health advisories, because they can travel deep into the lungs and enter the bloodstream, causing inflammation and chest constriction, reports The New York Times.The study revealed a measurable slowdown tied to PM2.5 levels. For every increase of one microgram per cubic meter increase in these tiny particles, the average finish time for runners dropped.In other words, on a day with even moderately elevated pollution, a runner's time could be slower by several minutes.The Los Angeles Marathon generally had the highest estimated median pollution levels and the slowest median finish times among the races studied. While this could owe to other factors like warmer weather and a hillier course, the overall pattern of slower finishes in more polluted races held true across all cities, even when comparing different years within the same marathon city.Boston had the fastest average finish time and one of the cleanest air levels among the cities, along with Minneapolis/St. Paul and New York City.What makes this finding particularly notable is that it affects even the fittest individuals. “What’s notable is that we’re looking at people who are all incredibly healthy,” Joseph Braun, a professor of epidemiology at Brown, told The New York Times. “But even among really healthy people, air pollution is having an important, albeit subtle, effect on your physiology.”Surprisingly, the slowdown was more pronounced for faster-than-average runners. Researchers suspect this may be because elite and competitive marathoners breathe in more air — and do so more rapidly — inhaling a larger dose of the pollution over the 26.2-mile course.PM2.5 primarily comes from the burning of fossil fuels — such as from power plants, gasoline or diesel vehicles — as well as from forest fires and wood burning. While air quality has improved in many U.S. regions, short-term spikes from sources like wildfire smoke have become a growing concern, The Times said. SOURCE: The New York Times, Nov. 1, 2025Copyright © 2025 HealthDay. All rights reserved.

New Study Links Wildfire Smoke to Premature Births

By I. Edwards HealthDay ReporterWEDNESDAY, Nov. 5, 2025 (HealthDay News) — Wildfire smoke may do more than harm the lungs.New research shows it...

WEDNESDAY, Nov. 5, 2025 (HealthDay News) — Wildfire smoke may do more than harm the lungs.New research shows it could also raise the risk of premature birth.A large study from the University of Washington found that pregnant people exposed to wildfire smoke were more likely to deliver early.The findings, published Nov. 3 in The Lancet Planetary Health, are based on more than 20,000 births across the United States between 2006 and 2020.About 10% of babies in the U.S. are born early, which can lead to lifelong health problems. While air pollution has already been linked to preterm birth, this is one of the biggest studies so far to look specifically at wildfire smoke as a contributor, researchers said.“Preventing preterm birth really pays off with lasting benefits for future health,” said lead author Allison Sherris, a postdoctoral researcher at the University of Washington in Seattle.“It’s also something of a mystery. We don’t always understand why babies are born preterm, but we know that air pollution contributes to preterm births, and it makes sense that wildfire smoke would as well," she added in a news release. "This study underscores that wildfire smoke is inseparable from maternal and infant health.”Researchers measured how often pregnant people were exposed to wildfire-related fine particle pollution, known as PM2.5, and how much they were exposed.The risk of preterm birth was higher when exposure happened in the second trimester, especially around week 21. Later in pregnancy, the biggest risk came from high levels of wildfire smoke, above 10 micrograms per cubic meter. The strongest link was seen in the Western U.S., where wildfire smoke has become more frequent and intense. “The second trimester is a period of pregnancy with the richest and most intense growth of the placenta, which itself is such an important part of fetal health, growth and development,” said co-author Dr. Catherine Karr, a professor of pediatrics and environmental health."So it may be that the wildfire smoke particles are really interfering with placental health," Karr added in a news release. "Some of them are so tiny that after inhalation they can actually get into the bloodstream and get delivered directly into the placenta or fetus.”Researchers say more work is needed to understand exactly how wildfire smoke affects pregnancy, but the evidence is now strong enough to take action for pregnant people."There’s an opportunity to work with clinicians to provide tools for pregnant people to protect themselves during smoke events," Sherris said. "Public health agencies’ messaging about wildfire smoke could also be tailored to pregnant people and highlight them as a vulnerable group."SOURCE: University of Washington, news release, Nov. 3, 2025Copyright © 2025 HealthDay. All rights reserved.

Light Pollution Harming Heart Health, Study Says

By Dennis Thompson HealthDay ReporterMONDAY, Nov. 3, 2025 (HealthDay News) — The bright lights of the big city might seem dazzling, but they can be...

By Dennis Thompson HealthDay ReporterMONDAY, Nov. 3, 2025 (HealthDay News) — The bright lights of the big city might seem dazzling, but they can be hard on your heart health, a new study says.People exposed to high levels of artificial light have an increasingly higher risk of heart disease, researchers are scheduled to report at a Nov. 10 meeting of the American Heart Association in New Orleans.Higher exposure to artificial light at night was associated with a 35% increased risk of heart disease within five years, and a 22% increased risk over 10 years, researchers found.“We found a nearly linear relationship between nighttime light and heart disease: the more night-light exposure, the higher the risk,” senior researcher Dr. Shady Abohashem, head of PET/CT cardiac imaging trials at Massachusetts General Hospital in Boston, said in a news release.For the new study, researchers analyzed the health of 466 adults with an average age of 55 who’d undergone a PET or CT scan at Massachusetts General Hospital between 2005 and 2008.The team compared the participants’ health and brain scans to their exposure to artificial light, based on their home address.Results showed that higher levels of artificial light caused brain stress activity and blood vessel inflammation.“Even modest increases in night-time light were linked with higher brain and artery stress,” Abohashem said. “When the brain perceives stress, it activates signals that can trigger an immune response and inflame the blood vessels. Over time, this process can contribute to hardening of the arteries and increase the risk of heart attack and stroke.”Over a decade, 17% of the people developed a major heart condition. Their light exposure was associated with risk of heart disease, even after accounting for other risk factors.Heart risks were even higher among people who lived in areas with high traffic noise, lower neighborhood income or other environmental factors that can add to stress, researchers said.To counter these ill effects, “people can limit indoor nighttime light, keeping bedrooms dark and avoiding screens such as TVs and personal electronic devices before bed,” Abohashem said.Cities also might improve folks’ health by reducing unnecessary outdoor lighting, shielding street lamps, or using motion-sensitive lights, researchers said.“These findings are novel and add to the evidence suggesting that reducing exposure to excessive artificial light at night is a public health concern,” Julio Fernandez-Mendoza, an American Heart Association spokesman, said in a news release.“We know too much exposure to artificial light at night can harm your health, particularly increasing the risk of heart disease. However, we did not know how this harm happened,” said Fernandez-Mendoza, director of behavioral sleep medicine at Pennsylvania State University College of Medicine, who was not involved in the study.“This study has investigated one of several possible causes, which is how our brains respond to stress,” he explained. “This response seems to play a big role in linking artificial light at night to heart disease.”Researchers next plan to see whether reducing nighttime light exposure might improve people’s heart health.Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.SOURCE: American Heart Association, news release, Nov. 3, 2025Copyright © 2025 HealthDay. All rights reserved.

Turns Out, There Are 5 Sleep Styles — And Each Affects Your Brain Differently

By I. Edwards HealthDay ReporterTHURSDAY, Oct. 9, 2025 (HealthDay News) — A new study suggests there’s more to sleep than how long you snooze each...

THURSDAY, Oct. 9, 2025 (HealthDay News) — A new study suggests there’s more to sleep than how long you snooze each night. Your overall sleep pattern could shape your mood, brain function and even long-term health.Researchers from Concordia University in Montreal identified five distinct sleep profiles that may help explain why some people feel well-rested while others struggle with fatigue, poor focus or emotional ups and downs.The findings, published Oct. 7 in PLOS Biology, show that these “sleep-biopsychosocial profiles” reflect a mix of biological, mental and environmental factors — from stress and emotions to bedroom comfort — that all affect how well you sleep.“People should treat their sleep seriously,” study co-author Valeria Kebets, a manager at Concordia’s Applied AI Institute, told NBC News. “It affects everything in their daily functioning.”The researchers identified five sleep profiles:1. Poor sleep and mental healthPeople in this group reported the worst sleep quality and higher levels of stress, fear and anger. They also had a greater risk of anxiety and depression.These individuals had poor mental health or attention issues but said their sleep felt fine, suggesting “sleep misperception,” or being unaware of underlying sleep problems, researchers said.3. Sleep aids and sociabilityThis group used sleep aids, but also reported strong social support and fewer feelings of rejection. However, they showed lower emotional awareness and weaker memory.4. Sleep duration and cognitionPeople sleeping fewer than six to seven hours a night scored lower on tests measuring problem-solving and emotional processing. They also showed higher aggression and irritability.5. Sleep disturbances and mental healthThose with issues like frequent waking, pain or temperature imbalance had higher rates of anxiety, substance use and poor cognitive performance.The study analyzed data from 770 healthy adults aged 22 to 36, using MRI scans and questionnaires about sleep, lifestyle and mood.Experts say the profiles could help doctors tailor sleep treatments in the future.“We really need to consider multiple sleep profiles in our research and clinic — the value of a multidimensional approach to data,” Dr. Phyllis Zee, director of the Center for Circadian and Sleep Medicine at Northwestern University, who was not involved in the study, told NBC News.Sleep experts also say the research reinforces the importance of good rest for both mental and physical health.“Sleep is a more complex issue than just how much time you spend in bed,” Dr. Rafael Pelayo, a sleep medicine specialist at Stanford University, said in the NBC News report. “If I can improve your sleep, it has downwind effects on your overall health — not just your mental health, but your physical health.”SOURCE: NBC News, Oct. 8, 2025Copyright © 2025 HealthDay. All rights reserved.

Wildfire Smoke Might Damage Male Fertility

By Dennis Thompson HealthDay ReporterTHURSDAY, Oct. 9, 2025 (HealthDay News) — Wildfire smoke could be damaging men’s fertility, according to a new...

By Dennis Thompson HealthDay ReporterTHURSDAY, Oct. 9, 2025 (HealthDay News) — Wildfire smoke could be damaging men’s fertility, according to a new study.Key measures of sperm quality appeared to drop among dozens of men participating in fertility treatments, researchers recently reported in the journal Fertility and Sterility.“These results reinforce growing evidence that environmental exposures — specifically wildfire smoke — can affect reproductive health,” said senior researcher Dr. Tristan Nicholson, an assistant professor of urology in the University of Washington School of Medicine in Seattle.“As we see more frequent and intense wildfire events, understanding how smoke exposure impacts reproductive health is critical,” she added in a news release.For the study, researchers analyzed semen samples from 84 men taken as part of intrauterine insemination procedures in the Seattle area between 2018 and 2022.Major wildfire smoke events hit Seattle in 2018, 2020 and 2022, researchers noted. The team compared the men’s sperm quality during and between these events.“This study takes advantage of our institution’s location in the Puget Sound region, where wildfire smoke events create distinct pre- and post-exposure periods in a natural experiment to examine how a sudden, temporary decline in air quality influences semen parameters,” researchers wrote.Results showed consistent declines in sperm concentration, total sperm count and sperm movement during wildfire smoke exposures.Wildfire smoke contains particle pollution that can invade a person’s organs through their lungs and bloodstream, researchers said.This exposure has previously been linked to lung cancer, respiratory disease, heart attack, stroke and mental impairment, but its effect on male fertility has not been well-studied, researchers said.Overall, the pregnancy rate among the men’s partners was 11%, and the live birth rate 9% — both at the low end of the average range, researchers noted.However, the team added that the study was not designed to fully evaluate the direct impact of wildfire smoke on reproductive outcomes.Researchers next plan to see what happens after wildfire smoke has dented a man’s fertility.“We are very interested in how and when sperm counts recover after wildfire smoke exposure,” Nicholson said. “Currently we are conducting a prospective pilot study of men in the Seattle area to evaluate how wildfire smoke affects sperm quality.”SOURCE: University of Washington, news release, Oct. 1, 2025Copyright © 2025 HealthDay. All rights reserved.

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