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Do Our Odds of Dying Ever Stop Increasing With Age? Scientists Disagree

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As we get older, our chances of dying go up. To that, you might say, well, duh. But, when we hit around 80 years old or so, a funny thing seems to happen: Our odds of dying stop increasing and instead start leveling out. So you’ve got the same shot — about 50/50 — of croaking at, say, 110 (an age that would classify you as a so-called supercentenarian) as you would at 95.

It’s an odd phenomenon that’s left experts puzzled for years. Researchers have floated many theories to try and explain it. For instance, some think maybe there’s some evolutionary quirk that allows this to happen. Others posit that maybe there’s some cellular funniness afoot, allowing people of extreme old age to somehow accumulate damage more slowly in their cells.

But some experts contend that maybe, this human mortality plateau isn’t happening at all. A new paper in PLOS Biology argues that most — if not all — of the proposed observations of so-called late-life mortality plateaus could be chalked up to scientific error.

The Illusion of Age Plateaus 

Saul Newman, a postdoc in machine learning and wheat genomics at the Australian National University in Canberra, is the sole author of the report. He argues that the aging plateaus researchers have documented in the past can be explained by a combination of errors related to the data sets they’ve used. Erroneous age reporting is one factor that could skew data. For example, he says in his paper, back in World War I, roughly 250,000 people in the U.K. reported being older than they were in order to join the fight.

But it seems the factors that can distort aging trends the most are the demographics researchers target for their studies and the accuracy of birth and death records they use.

Newman writes that our understanding of aging trends often relies on records from more than 90 years ago, which may not be all that reliable. In fact, even today, there are areas where record-keeping has some catching up to do; more than a third of global births still remain unreported. In some countries, there’s not even enough data to estimate births with any accuracy. Even in developed countries, he argues there aren’t any populations with accurate record-keeping big enough to examine late-life aging trends.

Still, it’s the records from those developed countries that underscore the point he’s trying to make. When you’re looking at populations where record-keeping is the strongest and most robust, the odds of late-life mortality plateaus occurring shrinks.

To demonstrate his claims, Newman used demographic data from international databases — including the U.N.’s World Population Prospects and the Human Mortality Database, maintained by teams from the University of California Berkeley and The Max Planck Institute for Demographic Research — to run his own statistical analysis. Essentially, he took this data and assumed that aging plateaus don’t exist and that instead, our mortality rates continue to increase as we age. Then, he introduced errors, such as ages being recorded incorrectly, into that data. He found that even when error rates were as low as one in 10,000, that was still enough to produce late-life mortality plateaus.

It’s “a blindingly simple explanation,” he says. “Until we have the human equivalent of tree-rings, an unforgeable measure of human age,” he writes in a follow-up email, “these data will remain dubious at best. Without a real, biological metric of human age, we cannot discriminate bureaucratic error from reality.”

A Push for Better Data

But Kenneth Wachter, a demographer and statistician at the University of California, Berkeley, argues Newman’s paper has its limits.

Though he concedes that many of the data sets that have been available can be laden with errors, he says researchers are working to change that. “Newman’s point really applies more to the official statistics that people have had to rely on, before big investments were made in individual age validation,” he says. “The new works that are coming out are really aimed at getting around the kinds of problems that Newman is featuring.”

He points to a study of his own, published in Science in June, which Newman has also criticized in a separate commentary released along with his PLOS Biology paper.

This Science paper relied on records from nearly 4,000 Italians, all of whom were confirmed to be 105 years old or older when the study was being conducted. That data was from the Italian National Institute of Statistics, which required that birth and death certificates be provided for everyone included in the sample. According to Wachter, the way those records were kept means the possibility of clerical errors is low. “Their birth records were kept in local municipalities in bound volumes, one volume for each year. So, a person who appears in the register for 1900 can’t have been born in 1910, the way Newman’s hypothetical model would say. In other kinds of studies, which are based simply on ages that people say they are, you can have the kinds of errors that Newman has hypothesized. Lots of people say they’re older than they are.”

A Fuzzy Future

Their argument underscores the tug of war that’s been ongoing and which has ramped up in recent years.

“It’s a big question,” Wachter says. But he’s optimistic about the future. He says the results that he and his team found “suggest flexibility in lifespans” and that “we haven’t seen all the progress that’s possible.”

Newman, though, is more cautious. “People have had this false dichotomy where they think that, oh there’s a limit, or there’s no limit, and it’s that simple,” he says. But he suspects it’s more nuanced. “There’s not one limit to human life. There’s a different limit to human life depending on where you’re from, what environment you grew up in, what time period you’re from and also what gender you are.”

He also thinks researchers’ time would be better spent digging into typical aging. “I would argue for less research on supercentenarians,” he writes in an email. “It is just unreliable data. That is not to say I think this research is not important. Instead, we must focus … on the ordinary aging of ordinary people.”

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Ecology

Globe Climate: Canada’s resource reckoning is coming

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Good afternoon, and welcome to Globe Climate, a newsletter about climate change, environment and resources in Canada.

This afternoon, the Alberta government announced that it is restoring a coal mining policy it revoked last spring. At the time, the move provoked a widespread public backlash detailed by The Globe. The original decision, which opened up more than 1.4 million hectares to exploration, was made without public consultation. Premier Jason Kenney previously defended the changes.

Lots more on coal and Canada’s resources industry in this week’s newsletter edition.

Now, let’s catch you up on other news.

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Ecology

‘Incredibly destructive’: Canada’s Prairies to see devastating impact of climate change

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As the climate continues to warm at an alarming rate, experts warn if dramatic steps to mitigate global warming are not taken, the effects in Canada’s Prairie region will be devastating to the country’s agriculture sector.

According to Environment and Climate Change Canada, the country is warming, on average, about double the global rate.

Scientists with the National Oceanic and Atmospheric Administration in the U.S. recently found 2020 was earth’s second-hottest year on record, with the average land and ocean surface temperature across the globe at 0.98 of a degree C above the 20th-century average.

However, the agency found the northern hemisphere saw its hottest year on record, at 1.28 degrees C above the average.

“(In Canada) we are looking at about 6.4C degrees of warming this century, which isn’t much less than one degree per decade, which is just a terrifying rate of warming,” Darrin Qualman, the director of climate crisis policy and action at the National Farmer’s Union said.

Qualman said there is “massive change coming” to Canada’s Prairies, which will be “incredibly destructive.”

“It’s not going too far to say that if we made that happen, parts of the Prairies wouldn’t be farmable anymore,” he said.

According to the federal government, in 2018 Canada’s agriculture and agri-food system generated $143 billion, accounting for 7.4 per cent of the country’s GDP.

The sector employed 2.3 million people in 2018. The majority of the 64.2 million hectares of farmland in Canada is concentrated in the Prairies and in southern Ontario.

The effects of climate change are already being felt on the ground in the Prairies, Qualman said, adding that the NFU has already heard from farmers complaining of “challenging weather.”

“People are sharing pictures of flattened crops and buildings, et cetera, that have been damaged,” he said. “And we’re still at the beginning of this.”

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Ecology

Insect-based dog food aims to cut your pet’s carbon pawprint

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Meat has an enormous carbon footprint, with livestock liable for about 15 per cent of worldwide emissions, as we have beforehand mentioned on this e-newsletter. That is prompted specialists to suggest consuming much less meat for sustainability (and well being) causes.

However what about your pet? One research discovered that the methane and nitrous oxide emissions generated by canine and cat meals within the U.S. alone had been equal to about 64 million tonnes of CO2, or roughly the quantity produced by 13.6 million automobiles. And it might be getting worse, with a development towards feeding pets “human-grade” meat.

That is prompted some pet meals makers to look to lower-carbon protein sources — together with bugs.

Research present that producing insect-based meals requires far much less feed, land and water and generates far fewer greenhouse fuel emissions per kilogram than meats comparable to beef, pork or rooster.

That is one of many causes increasingly more pet meals containing insect protein are hitting the market. Purina, a model owned by multinational Nestlé, launched a line of canine and cat meals containing black soldier fly larvae in Switzerland in November.

In Canada, Montreal-based Wilder Harrier began promoting canine treats made with cricket protein in 2015 and pet food made with black soldier fly larvae in 2019. It plans to broaden to launch a line of insect-based cat treats later this yr and cat meals in 2022 due to “a ton of demand,” mentioned firm co-founder Philippe Poirier.

Wilder Harrier initially labored with animal nutritionists on insect-based merchandise to unravel a unique downside — specifically, the founders’ canines had allergy symptoms to frequent meats utilized in canine meals. Poirier mentioned now about half its prospects hunt down the product due to their pets’ allergy symptoms and about half for environmental causes.

Dr. Cailin Heinze, a U.S.-based veterinary nutritionist licensed by the American School of Veterinary Vitamin, has written concerning the environmental influence of pet meals. She mentioned we’re typically “not as involved as we probably ought to [be]” concerning the environmental footprint of pets.

Alternatively, she famous that the longer-term influence of newer diets, comparable to vegan meals and people containing bugs, hasn’t been nicely examined in comparison with conventional pet meals.

Maria Cattai de Godoy, an assistant professor of animal sciences on the College of Illinois who research novel proteins for pet meals (together with bugs, yeast and plant-based substances), mentioned such substances are rigorously examined to find out their security and diet earlier than being added to pet meals. 

“This can be a very extremely regulated trade,” she mentioned, however admitted it is also evolving.

Relating to bugs, she mentioned constructive information “reveals promise in direction of utilizing them increasingly more in pet meals.” Insect-based proteins have additionally earned the endorsement of the British Veterinary Affiliation, which says some insect-based meals could also be higher for pets than prime steak.

However Godoy famous that there isn’t any one-size-fits-all resolution, and pet homeowners ought to take into consideration the wants of their very own particular person pet and analysis whether or not a specific weight loss plan can be appropriate.

She mentioned that other than the kind of protein, issues like packaging and manufacturing strategies may also make a distinction. For instance, utilizing meat byproducts that may in any other case turn into waste would not drive elevated meat manufacturing the identical approach as utilizing human-grade meat.

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