Connect with us

Science

Aging Women’s Brain Mysteries Are Tested in Trio of Studies

Published

on

Aging Women’s Brain Mysteries Are Tested in Trio of Studies

Women’s brains are superior to men’s in at least in one respect — they age more slowly. And now, a group of researchers reports that they have found a gene in mice that rejuvenates female brains.

Humans have the same gene. The discovery suggests a possible way to help both women and men avoid cognitive declines in advanced age.

The study was published Wednesday in the journal Science Advances. The journal also published two other studies on women’s brains, one on the effect of hormone therapy on the brain and another on how age at the onset of menopause shapes the risk of getting Alzheimer’s disease.

The evidence that women’s brains age more slowly than men’s seemed compelling.

Researchers, looking at the way the brain uses blood sugar, had already found that the brains of aging women are years younger, in metabolic terms, than the brains of aging men.

Advertisement

Other scientists, examining markings on DNA, found that female brains are a year or so younger than male brains.

And careful cognitive studies of healthy older people found that women had better memories and cognitive function than men of the same age.

Dr. Dena Dubal, a professor of neurology at the University of California, San Francisco, set out to understand why.

“We really wanted to know what could underlie this female resilience,” Dr. Dubal said. So she and her colleagues focused on the one factor that differentiates females and males: the X chromosome. Females have two X chromosomes; males have one X and one Y chromosome.

Early in pregnancy, one of the X chromosomes in females shuts down and its genes go nearly silent. But that silencing changes in aging, Dr. Dubal found.

Advertisement

She and her colleagues looked in the hippocampus, the brain’s center of memory and cognition, which deteriorates as one ages and is ravaged by Alzheimer’s.

When looking at aging hippocampuses, “we were astounded to find that genes woke up,” Dr. Dubal said, referring to the silent X chromosomes. The study was done in aging mice, but the researchers believe the finding is applicable to humans because mice show the same age-related effects on brain functioning, with females performing better than males.

Her group focused on one particular awakened gene, Plp1. It makes a protein that is part of myelin, a fatty sheath around nerve cells that “allows information to flow back and forth, like a highway,” Dr. Dubal said.

What would happen, she asked, if she used gene therapy to give aging male mice a dose of Plp1 in their hippocampuses?

Her team found that the mice regained memory and cognition. They did not even have to give the gene to many cells, Dr. Dubal added. “Just a little boost went a long way,” she said.

Advertisement

Then she gave the gene therapy to female mice, although they were already making Plp1. Their memories and cognition got even better.

“I’m so excited about this,” Dr. Dubal said. “Even an old brain can become more youthful and function better.”

Millions of women use hormone therapy to relieve symptoms of menopause like hot flashes and vaginal dryness, but there remains a concern about how it might affect the brain.

The issue was raised when a large and rigorous federal study, the Women’s Health Initiative, published in 2003, concluded that Prempro, a popular hormone treatment at the time, doubled the risk of dementia.

Since then, other scientists have argued that the risk depends on when a woman takes hormones. If she takes them within 10 years of menopause, they say, her brain will be fine. Current treatment guidelines reflect that view.

Advertisement

To examine what happens inside the brain after hormone therapy, Rachel F. Buckley, a neuroscientist at Massachusetts General Hospital, and her colleagues recruited 146 healthy women aged 51 to 89. They scanned the women’s brains for tau, a protein that accumulates in the brains of people with Alzheimer’s.

The investigators knew only the ages of the women, and whether they had ever taken hormone therapy. To Dr. Buckley’s surprise, they saw an effect.

The women over 70 who had received hormone therapy had a greater accumulation of tau than the women who had never had it. Having more tau did not mean the women had Alzheimer’s, but it could have put them on the path toward the disease.

Women under 70 in the study did not have more tau in their brains. But, the researchers said, they did not know if younger women who took hormones would have more tau later in life.

The study was observational, meaning it cannot prove cause and effect. The women with more tau might have been different in other ways that the researchers did not account for, which has left uncertainty about the finding.

Advertisement

Dr. Buckley, asked what advice she would give women about hormone therapy and the risk of Alzheimer’s, said “talk to your doctor,” acknowledging that it was not a satisfactory answer.

Another study published on Wednesday used clinical records and autopsy data to compare the brains of 268 women. Some started menopause early, around age 45, while the rest started at the more typical age of around 50.

The researchers who led the study reported that age at the start of menopause had no effect on cognitive decline, the integrity of brain synapses or on brain markers of Alzheimer’s.

The results, said Madeline Wood Alexander, the study’s lead author and a doctoral student at Sunnybrook Research Institute in Toronto, were “not what we expected.” The researchers thought the women who started menopause earlier would have worse brain functioning. That is because levels of estrogen, which can protect neurons, plummet at menopause, the authors said.

The researchers did identify one correlation that they emphasized as their main finding: The synapses of women who begin menopause earlier may become more vulnerable to changes linked to Alzheimer’s as they naturally deteriorate.

Advertisement

They reported that they did not see that effect in women with early menopause who used hormone therapy.

The result clashes with those of the other study, which indicated hormone therapy might increase the risk of Alzheimer’s-like changes in the brain. There was no clear explanation for the seemingly contradictory findings.

But experts not involved with either study questioned the conclusions about early menopause and hormone therapy. They said they were not convinced by the statistical analyses and modeling that led to this correlation.

Dr. Deborah Grady, emeritus professor of epidemiology and biostatistics at the University of California, San Francisco, said it was difficult to interpret studies that looked at things like the vulnerability of synapses. If menopause timing had an effect, she said, she’d like to see it show up in the actual incidence of Alzheimer’s in these women.

Dr. Jacques Rossouw, who was a program officer for the Women’s Health Initiative, had a similar concern. He added that the authors did so many statistical tests that it was possible the correlation they found occurred by chance.

Advertisement

And even if it is real, he said, “this can’t be a big effect if there was no effect of age of menopause on Alzheimer’s pathology.”

Science

California regulators approve rules to curb methane leaks and prevent fires at landfills

Published

on

California regulators approve rules to curb methane leaks and prevent fires at landfills

In one of the most important state environmental decisions this year, California air regulators adopted new rules designed to reduce methane leaks and better respond to disastrous underground fires at landfills statewide.

California Air Resources Board members voted 12-0 on Thursday to approve a batch of new regulations for the state’s nearly 200 large landfills, designed to minimize the release of methane, a powerful greenhouse gas produced by decomposing organic waste. Landfills are California’s second-largest source of methane emissions, following only the state’s large dairy cow and livestock herds.

The new requirements will force landfill operators to install additional pollution controls; more comprehensively investigate methane leaks on parts of landfills that are inaccessible with on-the-ground monitoring using new technology like drones and satellites; and fix equipment breakdowns much faster. Landfill operators also will be required to repair leaks identified through California’s new satellite-detection program.

The regulation is expected to prevent the release of 17,000 metric tons of methane annually — an amount capable of warming the atmosphere as much as 110,000 gas-fired cars driven for a year.

Advertisement

It also will curtail other harmful landfill pollution, such as lung-aggravating sulfur and cancer-causing benzene. Landfill operators will be required to keep better track of high temperatures and take steps to minimize the fire risks that heat could create.

There are underground fires burning in at least two landfills in Southern California — smoldering chemical reactions that are incinerating buried garbage, releasing toxic fumes and spewing liquid waste. Regulators found explosive levels of methane emanating from many other landfills across the state.

During the three-hour Air Resources Board hearing preceding the vote, several Californians who live near Chiquita Canyon Landfill — one of the known sites where garbage is burning deep underground — implored the board to act to prevent disasters in other communities across the state.

“If these rules were already updated, maybe my family wouldn’t be sick,” said Steven Howse, a 27-year resident of Val Verde. “My house wouldn’t be for sale. My close friend and neighbor would still live next door to me. And I wouldn’t be pleading with you right now. You have the power to change this.”

Landfill operators, including companies and local governments, voiced their concern about the costs and labor needed to comply with the regulation.

Advertisement

“We want to make sure that the rule is implementable for our communities, not unnecessarily burdensome,” said John Kennedy, a senior policy advocate for Rural County Representatives of California, a nonprofit organization representing 40 of the state’s 58 counties, many of which own and operate landfills. “While we support the overarching goals of the rule, we remain deeply concerned about specific measures including in the regulation.”

Lauren Sanchez, who was appointed chair of the California Air Resources Board in October, recently attended the United Nations’ COP30 climate conference in Brazil with Gov. Gavin Newsom. What she learned at the summit, she said, made clear to her that California’s methane emissions have international consequences, and that the state has an imperative to reduce them.

“The science is clear, acting now to reduce emissions of methane and other short-lived climate pollutants is the best way to immediately slow the pace of climate change,” Sanchez said.

Advertisement
Continue Reading

Science

See How Home Insurance Premiums Are Changing Near You

Published

on

See How Home Insurance Premiums Are Changing Near You

Insurance premiums are rising fast in the parts of the United States most exposed to climate-related disasters like wildfires and hurricanes.

New research shows that, as insurance has sharply pushed up the cost of owning a home, the price shock is starting to reverberate through the broader real estate market.

Advertisement

Rising insurance costs are eating into household budgets.

Advertisement

Note: “High end” refers to the top decile of homeowner payments in each county. The 2023 values are shown for Vermont because of discrepancies in the source data.

The New York Times

Advertisement

In some areas of the country that are exposed to disasters, homes are not selling because prospective buyers can’t afford both the mortgage and the insurance.

In parts of the hail-prone Midwestern states, insurance now eats up more than one-fifth of the average homeowner’s total housing payments, including mortgage costs and property taxes. In Orleans Parish, La., that number is nearly 30 percent.

Advertisement

Home insurance costs have soared where climate hazards are highest.

Advertisement

Source: Keys and Mulder (National Bureau of Economic Research, 2025)

Note: The 2023 values are shown for Vermont because of discrepancies in the source data.

Advertisement

The New York Times

Nationally, insurance rates have risen by an average of 58 percent since 2018, outpacing inflation by a substantial margin. But that growth has been highly uneven across the United States.

Advertisement

Source: Keys and Mulder (National Bureau of Economic Research, 2025)

Advertisement

Note: “High end” refers to the top decile of homeowner payments in each county. The 2023 values are shown for Vermont because of discrepancies in the source data.

The New York Times

Advertisement

Places that are most vulnerable to climate-related disasters like hurricanes, fires and hail are seeing some of the largest premium increases. It’s not always the case that the highest climate risk translates into the highest insurance costs. Local policies and regulations have helped keep prices lower in high-risk places, like parts of California. Other factors, like a homeowner’s credit score, can affect premiums, too.

What’s driving up insurance prices?

Advertisement

Since 2017, an obscure part of the insurance market, known as reinsurance, has helped push up premiums. Insurance companies buy reinsurance to help limit their exposure when a catastrophe hits. Over the past several years, reinsurance companies have experienced what Benjamin Keys and Philip Mulder, the researchers who led the new study, call a “climate epiphany.” As a result, the rates they charge to protect home insurance companies against catastrophic losses have roughly doubled.

Insurance providers have, in turn, passed these costs on to homeowners. The rapid repricing of climate risk is responsible for about 20 percent of home insurance premium increases since 2017, according to Dr. Keys and Dr. Mulder.

What else is contributing to high rates? Rebuilding costs are responsible for about 35 percent of the recent changes, the research found. Population shifts and inflation are factors, too.

Advertisement

High insurance prices are weighing down home values.

Since 2018, a financial shock in the home insurance market has meant that homes in the ZIP codes most exposed to hurricanes and wildfires sell for an average of $43,900 less than they otherwise would have, the research found.

Advertisement

Source: Zillow

Advertisement

Note: Chart shows percent change in Zillow Home Value Index since 2018.

The New York Times

Advertisement

In many places, insurance has been a relatively small part of the homebuying equation. Now, for many, it’s a major consideration.

For several homeowners we interviewed in Louisiana, monthly insurance costs are now higher than their home loan payments.

The research shows buyers may be factoring rising insurance costs into the prices they’re willing to pay for homes. As a result, homes in some areas are selling for less.

Advertisement

Advertisement

Methodology

Benjamin Keys and Philip Mulder calculated annual homeowners’ insurance costs by separating mortgage and tax payments from loan-level escrow data obtained from CoreLogic, a property and risk analytics firm. Households whose payments were captured by CoreLogic were not necessarily present in all years of data from 2014 to 2024.

Advertisement

The home insurance share of total home payments is based on mean values. Total home payments include insurance, property tax and mortgage principal and interest costs. Escrow payments typically do not include utilities, homeowners’ association fees.

Continue Reading

Science

L.A. County’s first flu death confirmed in a season that could be harsh

Published

on

L.A. County’s first flu death confirmed in a season that could be harsh

L.A. County has had its first flu death in a season that health officials have warned could be severe.

The county Department of Public Health confirmed the influenza-associated fatality on Wednesday.

The death occurred in an elderly individual with underlying health conditions who had not received a flu vaccination this season, according to the Department of Public Health.

“We send our condolences to the family and loved ones of the person we lost. This tragic death reminds us how serious influenza can be,” Dr. Muntu Davis, Los Angeles County health officer, said in a news release.

Advertisement

Flu activity is low at the moment, though it is likely to increase with Thanksgiving next week and the holiday season, which typically involves more plane travel and indoor gatherings.

Last year’s flu season was the worst California had seen in years — and state health officials have already warned that this year could be just as bad.

Health experts, including the Centers for Disease Control and Prevention, recommend an annual flu vaccination for everyone older than 6 months.

Nationwide, the number of children who died from flu last season — 280 — was the highest in about 15 years, according to one report. About 9 in 10 of those children were not vaccinated, officials said.

The flu vaccine can be administered at the same time as the COVID-19 vaccine and takes two weeks for protection to develop.

Advertisement

“You can also reduce your risk by taking simple but powerful steps,” Davis said. “[W]ash your hands frequently, stay home and away from others when you feel sick, and wear a well-fitting mask in crowded indoor spaces, around people at higher risk, or whenever you have symptoms.”

As respiratory virus activity increases in L.A. County, the Department of Public Health also recommends that everyone 6 months and older receive an updated COVID-19 vaccine. RSV immunization is also recommended for older adults, pregnant people and infants.

L.A. County residents can find a vaccine site near them by visiting the department’s website.

Advertisement
Continue Reading

Trending