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Older People Seeking Care for Cannabis Use at Greater Risk for Dementia, Study Finds

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Older People Seeking Care for Cannabis Use at Greater Risk for Dementia, Study Finds

Middle-aged and older adults who sought hospital or emergency room care because of cannabis use were almost twice as likely to develop dementia over the next five years, compared with similar people in the general population, a large Canadian study reported on Monday.

When compared with adults who sought care for other reasons, the risk of developing dementia was still 23 percent higher among users of cannabis, the study also found.

The study included the medical records of six million people in Ontario from 2008 to 2021. The authors accounted for health and sociodemographic differences between comparison groups, some of which play a role in cognitive decline.

The data do not reveal how much cannabis the subjects had been using, and the study does not prove that regular or heavy cannabis use plays a causal role in dementia.

But the finding does raise serious concerns that require further exploration, said Dr. Daniel T. Myran, the first author of the study, which was published in JAMA Neurology.

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“Figuring out whether or not cannabis use or heavy regular chronic use causes dementia is a challenging and complicated question that you don’t answer in one study,” said Dr. Myran, an assistant professor of family medicine at University of Ottawa.

“This contributes to the literature and to a sign, or signal, of concern.”

Dr. Myran’s previous research has found that patients with cannabis use disorder died at almost three times the rate of individuals without the disorder over a five-year period. He has also reported that more cases of schizophrenia and psychosis in Canada have been linked to cannabis use disorder since the drug was legalized.

The latest study, focusing on dementia, adds to a growing body of literature on regular or heavy cannabis use and cognition. Researchers have reported impacts on verbal learning, memory and attention, while imaging studies have pointed to changes in the brain related to the use of cannabis and other substances.

Veterans with traumatic brain injuries in addition to cannabis use disorder may be at heightened risk for early-onset dementia, researchers reported last year.

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But many of the studies are relatively small. The new report’s strength was its large sample and the ability to track patients over time who did not have a diagnosis of dementia when they entered the study, said Madeline Meier, an associate professor of psychology at Arizona State University, who was not involved in the study.

“They were able to rule out dementia at the time of the first cannabis visit, and were able to show the temporal order — the cannabis came first, and the dementia came second,” said Dr. Meier.

Her research, which has followed and periodically tested a cohort of over 1,000 individuals over a period of many years, has linked cannabis use and neuropsychological decline.

“I think you want to combat this whole idea that cannabis is harmless and maybe even has some medical benefits,” Dr. Meier said. “This study is showing an association that I think people should take seriously and say, ‘Maybe this is putting me at risk.’”

She noted that the work by Dr. Myran and his colleagues also found that people seeking care for alcohol use were even more likely to receive a dementia diagnosis than were cannabis users.

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“I’m worried about the substance abuse in that Baby Boomer age,” she said.

More and more people, including seniors, are using cannabis. Medical visits related to cannabis increased more than fivefold among adults 45 and older between 2008 and 2021, the new study found. Among adults 65 and over, visits increased almost 27-fold.

The study included more than 6 million people age 45 and over who did not have a diagnosis of dementia at the start of the research. Of them, 16,275 had an acute-care medical encounter because of cannabis.

The patients with cannabis-related visits were compared to the matched general population, and in a separate comparison, to 140,824 matched patients who needed medical care for all other reasons.

Within five years, 5 percent of those with acute care cannabis visits received a dementia diagnosis. The figure for individuals needing care for other reasons was 3.6 percent, and for similar individuals in the general population, 1.3 percent.

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But people who are heavy cannabis users differ from those who are not in a variety of ways, some of which may help explain the increased risk for dementia, Dr. Myran explained.

While some of the factors can be accounted for, he said, “you can’t control for all of them.”

Another unknown is self-medication, he said. Someone who has started experiencing symptoms of cognitive decline may be more likely to turn to cannabis. If so, then “it looks as if the cannabis is causing dementia, but it’s just on the pathway — they were already developing dementia,” Dr. Myran said.

After making adjustments for age, sex, income and other factors, including other health conditions, he and his colleagues determined that patients who sought care for cannabis-related reasons were 1.23 times as likely as those who had gotten any kind of acute care to be diagnosed with dementia, and 1.72 times as likely as those in the healthier general population.

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Commentary: My toothache led to a painful discovery: The dental care system is full of cavities as you age

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Commentary: My toothache led to a painful discovery: The dental care system is full of cavities as you age

I had a nagging toothache recently, and it led to an even more painful revelation.

If you X-rayed the state of oral health care in the United States, particularly for people 65 and older, the picture would be full of cavities.

“It’s probably worse than you can even imagine,” said Elizabeth Mertz, a UC San Francisco professor and Healthforce Center researcher who studies barriers to dental care for seniors.

Mertz once referred to the snaggletoothed, gap-filled oral health care system — which isn’t really a system at all — as “a mess.”

But let me get back to my toothache, while I reach for some painkiller. It had been bothering me for a couple of weeks, so I went to see my dentist, hoping for the best and preparing for the worst, having had two extractions in less than two years.

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Let’s make it a trifecta.

My dentist said a molar needed to be yanked because of a cellular breakdown called resorption, and a periodontist in his office recommended a bone graft and probably an implant. The whole process would take several months and cost roughly the price of a swell vacation.

I’m lucky to have a great dentist and dental coverage through my employer, but as anyone with a private plan knows, dental insurance can barely be called insurance. It’s fine for cleanings and basic preventive routines. But for more complicated and expensive procedures — which multiply as you age — you can be on the hook for half the cost, if you’re covered at all, with annual payout caps in the $1,500 range.

“The No. 1 reason for delayed dental care,” said Mertz, “is out-of-pocket costs.”

So I wondered if cost-wise, it would be better to dump my medical and dental coverage and switch to a Medicare plan that costs extra — Medicare Advantage — but includes dental care options. Almost in unison, my two dentists advised against that because Medicare supplemental plans can be so limited.

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Sorting it all out can be confusing and time-consuming, and nobody warns you in advance that aging itself is a job, the benefits are lousy, and the specialty care you’ll need most — dental, vision, hearing and long-term care — are not covered in the basic package. It’s as if Medicare was designed by pranksters, and we’re paying the price now as the percentage of the 65-and-up population explodes.

So what are people supposed to do as they get older and their teeth get looser?

A retired friend told me that she and her husband don’t have dental insurance because it costs too much and covers too little, and it turns out they’re not alone. By some estimates, half of U.S. residents 65 and older have no dental insurance.

That’s actually not a bad option, said Mertz, given the cost of insurance premiums and co-pays, along with the caps. And even if you’ve got insurance, a lot of dentists don’t accept it because the reimbursements have stagnated as their costs have spiked.

But without insurance, a lot of people simply don’t go to the dentist until they have to, and that can be dangerous.

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“Dental problems are very clearly associated with diabetes,” as well as heart problems and other health issues, said Paul Glassman, associate dean of the California Northstate University dentistry school.

There is one other option, and Mertz referred to it as dental tourism, saying that Mexico and Costa Rica are popular destinations for U.S. residents.

“You can get a week’s vacation and dental work and still come out ahead of what you’d be paying in the U.S.,” she said.

Tijuana dentist Dr. Oscar Ceballos told me that roughly 80% of his patients are from north of the border, and come from as far away as Florida, Wisconsin and Alaska. He has patients in their 80s and 90s who have been returning for years because in the U.S. their insurance was expensive, the coverage was limited and out-of-pocket expenses were unaffordable.

“For example, a dental implant in California is around $3,000-$5,000,” Ceballos said. At his office, depending on the specifics, the same service “is like $1,500 to $2,500.” The cost is lower because personnel, office rent and other overhead costs are cheaper than in the U.S., Ceballos said.

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As we spoke by phone, Ceballos peeked into his waiting room and said three patients were from the U.S. He handed his cellphone to one of them, San Diegan John Lane, who said he’s been going south of the border for nine years.

“The primary reason is the quality of the care,” said Lane, who told me he refers to himself as 39, “with almost 40 years of additional” time on the clock.

Ceballos is “conscientious and he has facilities that are as clean and sterile and as medically up to date as anything you’d find in the U.S.,” said Lane, who had driven his wife down from San Diego for a new crown.

“The cost is 50% less than what it would be in the U.S.,” said Lane, and sometimes the savings is even greater than that.

Come this summer, Lane may be seeing even more Californians in Ceballos’ waiting room.

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“Proposed funding cuts to the Medi-Cal Dental program would have devastating impacts on our state’s most vulnerable residents,” said dentist Robert Hanlon, president of the California Dental Assn.

Dental student Somkene Okwuego smiles after completing her work on patient Jimmy Stewart, 83, who receives affordable dental work at the Ostrow School of Dentistry of USC on the USC campus in Los Angeles on February 26, 2026.

(Genaro Molina / Los Angeles Times)

Under Proposition 56’s tobacco tax in 2016, supplemental reimbursements to dentists have been in place, but those increases could be wiped out under a budget-cutting proposal. Only about 40% of the state’s dentists accept Medi-Cal payments as it is, and Hanlon told me a CDA survey indicates that half would stop accepting Medi-Cal patients and many others will accept fewer patients.

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“It’s appalling that when the cost of providing healthcare is at an all-time high, the state is considering cutting program funding back to 1990s levels,” Hanlon said. “These cuts … will force patients to forgo or delay basic dental care, driving completely preventable emergencies into already overcrowded emergency departments.”

Somkene Okwuego, who as a child in South L.A. was occasionally a patient at USC’s Herman Ostrow School of Dentistry clinic, will graduate from the school in just a few months.

I first wrote about Okwuego three years ago, after she got an undergrad degree in gerontology, and she told me a few days ago that many of her dental patients are elderly and have Medi-Cal or no insurance at all. She has also worked at a Skid Row dental clinic, and plans after graduation to work at a clinic where dental care is free or discounted.

Okwuego said “fixing the smiles” of her patients is a privilege and boosts their self-image, which can help “when they’re trying to get jobs.” When I dropped by to see her Thursday, she was with 83-year-old patient Jimmy Stewart.

Stewart, an Army veteran, told me he had trouble getting dental care at the VA and had gone years without seeing a dentist before a friend recommended the Ostrow clinic. He said he’s had extractions and top-quality restorative care at USC, with the work covered by his Medi-Cal insurance.

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I told Stewart there could be some Medi-Cal cuts in the works this summer.

“I’d be screwed,” he said.

Him and a lot of other people.

steve.lopez@latimes.com

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Diablo Canyon clears last California permit hurdle to keep running

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Diablo Canyon clears last California permit hurdle to keep running

Central Coast Water authorities approved waste discharge permits for Diablo Canyon nuclear plant Thursday, making it nearly certain it will remain running through 2030, and potentially through 2045.

The Pacific Gas & Electric-owned plant was originally supposed to shut down in 2025, but lawmakers extended that deadline by five years in 2022, fearing power shortages if a plant that provides about 9 percent the state’s electricity were to shut off.

In December, Diablo Canyon received a key permit from the California Coastal Commission through an agreement that involved PG&E giving up about 12,000 acres of nearby land for conservation in exchange for the loss of marine life caused by the plant’s operations.

Today’s 6-0 vote by the Central Coast Regional Water Board approved PG&E’s plans to limit discharges of pollutants into the water and continue to run its “once-through cooling system.” The cooling technology flushes ocean water through the plant to absorb heat and discharges it, killing what the Coastal Commission estimated to be two billion fish each year.

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The board also granted the plant a certification under the Clean Water Act, the last state regulatory hurdle the facility needed to clear before the federal Nuclear Regulatory Commission (NRC) is allowed to renew its permit through 2045.

The new regional water board permit made several changes since the last one was issued in 1990. One was a first-time limit on the chemical tributyltin-10, a toxic, internationally-banned compound added to paint to prevent organisms from growing on ship hulls.

Additional changes stemmed from a 2025 Supreme Court ruling that said if pollutant permits like this one impose specific water quality requirements, they must also specify how to meet them.

The plant’s biggest water quality impact is the heated water it discharges into the ocean, and that part of the permit remains unchanged. Radioactive waste from the plant is regulated not by the state but by the NRC.

California state law only allows the plant to remain open to 2030, but some lawmakers and regulators have already expressed interest in another extension given growing electricity demand and the plant’s role in providing carbon-free power to the grid.

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Some board members raised concerns about granting a certification that would allow the NRC to reauthorize the plant’s permits through 2045.

“There’s every reason to think the California entities responsible for making the decision about continuing operation, namely the California [Independent System Operator] and the Energy Commission, all of them are sort of leaning toward continuing to operate this facility,” said boardmember Dominic Roques. “I’d like us to be consistent with state law at least, and imply that we are consistent with ending operation at five years.”

Other board members noted that regulators could revisit the permits in five years or sooner if state and federal laws changes, and the board ultimately approved the permit.

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Deadly bird flu found in California elephant seals for the first time

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Deadly bird flu found in California elephant seals for the first time

The H5N1 bird flu virus that devastated South American elephant seal populations has been confirmed in seals at California’s Año Nuevo State Park, researchers from UC Davis and UC Santa Cruz announced Wednesday.

The virus has ravaged wild, commercial and domestic animals across the globe and was found last week in seven weaned pups. The confirmation came from the U.S. Department of Agriculture’s National Veterinary Services Laboratory in Ames, Iowa.

“This is exceptionally rapid detection of an outbreak in free-ranging marine mammals,” said Professor Christine Johnson, director of the Institute for Pandemic Insights at UC Davis’ Weill School of Veterinary Medicine. “We have most likely identified the very first cases here because of coordinated teams that have been on high alert with active surveillance for this disease for some time.”

Since last week, when researchers began noticing neurological and respoiratory signs of the disease in some animals, 30 seals have died, said Roxanne Beltran, a professor of ecology and evolutionary biology at UC Santa Cruz. Twenty-nine were weaned pups and the other was an adult male. The team has so far confirmed the virus in only seven of the dead pups.

Infected animals often have tremors convulsions, seizures and muscle weakness, Johnson said.

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Beltran said teams from UC Santa Cruz, UC Davis and California State Parks monitor the animals 260 days of the year, “including every day from December 15 to March 1” when the animals typically come ashore to breed, give birth and nurse.

The concerning behavior and deaths were first noticed Feb. 19.

“This is one of the most well-studied elephant seal colonies on the planet,” she said. “We know the seals so well that it’s very obvious to us when something is abnormal. And so my team was out that morning and we observed abnormal behaviors in seals and increased mortality that we had not seen the day before in those exact same locations. So we were very confident that we caught the beginning of this outbreak.”

In late 2022, the virus decimated southern elephant seal populations in South America and several sub-Antarctic Islands. At some colonies in Argentina, 97% of pups died, while on South Georgia Island, researchers reported a 47% decline in breeding females between 2022 and 2024. Researchers believe tens of thousands of animals died.

More than 30,000 sea lions in Peru and Chile died between 2022 and 2024. In Argentina, roughly 1,300 sea lions and fur seals perished.

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At the time, researchers were not sure why northern Pacific populations were not infected, but suspected previous or milder strains of the virus conferred some immunity.

The virus is better known in the U.S. for sweeping through the nation’s dairy herds, where it infected dozens of dairy workers, millions of cows and thousands of wild, feral and domestic mammals. It’s also been found in wild birds and killed millions of commercial chickens, geese and ducks.

Two Americans have died from the virus since 2024, and 71 have been infected. The vast majority were dairy or commercial poultry workers. One death was that of a Louisiana man who had underlying conditions and was believed to have been exposed via backyard poultry or wild birds.

Scientists at UC Santa Cruz and UC Davis increased their surveillance of the elephant seals in Año Nuevo in recent years. The catastrophic effect of the disease prompted worry that it would spread to California elephant seals, said Beltran, whose lab leads UC Santa Cruz’s northern elephant seal research program at Año Nuevo.

Johnson, the UC Davis researcher, said the team has been working with stranding networks across the Pacific region for several years — sampling the tissue of birds, elephant seals and other marine mammals. They have not seen the virus in other California marine mammals. Two previous outbreaks of bird flu in U.S. marine mammals occurred in Maine in 2022 and Washington in 2023, affecting gray and harbor seals.

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The virus in the animals has not yet been fully sequenced, so it’s unclear how the animals were exposed.

“We think the transmission is actually from dead and dying sea birds” living among the sea lions, Johnson said. “But we’ll certainly be investigating if there’s any mammal-to-mammal transmission.”

Genetic sequencing from southern elephant seal populations in Argentina suggested that version of the virus had acquired mutations that allowed it to pass between mammals.

The H5N1 virus was first detected in geese in China in 1996. Since then it has spread across the globe, reaching North America in 2021. The only continent where it has not been detected is Oceania.

Año Nuevo State Park, just north of Santa Cruz, is home to a colony of some 5,000 elephant seals during the winter breeding season. About 1,350 seals were on the beach when the outbreak began. Other large California colonies are located at Piedras Blancas and Point Reyes National Sea Shore. Most of those animals — roughly 900 — are weaned pups.

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It’s “important to keep this in context. So far, avian influenza has affected only a small proportion of the weaned at this time, and there are still thousands of apparently healthy animals in the population,” Beltran said in a press conference.

Public access to the park has been closed and guided elephant seal tours canceled.

Health and wildlife officials urge beachgoers to keep a safe distance from wildlife and keep dogs leashed because the virus is contagious.

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