Friday, December 31, 2021

Our lung capacity has gotten a lot better

Norwegian researchers and thousands of residents in the county of Trøndelag have taken part in a study that shows how year after year —ever since the end of the 19th century — our lungs work better and better.

For many years now, doctors and other health personnel in Norway and several other European countries have surveyed people’s lung capacity. They have surveyed a total of almost a quarter of a million Europeans.

Now these measurements have been assembled in a single large study.

“We assumed that the lung capacity of people had improved, but we had no idea that the improvement would be so big. This is a very exciting result,” said medical doctor and researcher Sigrid Aalberg Vikjord to

Vikjord and Arnulf Langhammer, both researchers with the Trøndelag Health Study (HUNT), are the two Norwegian participants in the international team, which has now published an article in the academic journal The Lancet about the research results.
A few millilitres each year

“Every single year, people have on average increased their breathing capacity by a few millilitres,” Vikjord said.

“The increase is small, year by year. But when it extends over many years, there is a clear improvement in how much air the lungs are able to draw in and exhale.”

Vikjord says that the researchers have collected the results from a total of ten large European population studies on health. The Norwegian figures are from HUNT and the former county of Nord-Trøndelag.
From 1884 to 1996

The participants in the study were born between 1884 and 1996.

All have been non-smokers. The lung capacity measurements were made while the study participants were between 20 and 94 years old.

All these studies used a method called spirometry to measure people's lung capacity. Spirometry measures the volume of air a person is able to exhale, after the person first draws as much air as possible into the lungs.
What explains the increase?

There are several possible explanations for why our lung capacity has increased so much.

“We first assumed that the explanation could be that people have become taller, so that their lungs have grown larger and have greater capacity,” Vikjord said.

“But we see that it takes more than just the increase in people's height to explain the increase in lung capacity that we found,” she said.

“One additional explanation may be that there are better treatments for most of the diseases that affect lung function,” she said.

“At the same time, fewer and fewer people are exposed to passive smoking. We as a society have also become more aware of the negative effects of other kinds of air pollution.”
Should change criteria

The fact that people on average have improved lung capacity means that the health service should now change its diagnostic criteria for lung diseases, the researchers suggest in The Lancet article.

Essentially, the criterion for what is normal lung capacity should be changed.

“The data we use to diagnose today's patients are outdated,” Vikjord said.

“We have to take into account that conditions are completely different for a twenty-year-old born in 1920 and a twenty-year-old born in 1980. For example, this difference could mean that we risk diagnosing too many people with COPD (chronic obstructive pulmonary disease),” she said.

“At the same time, if we use incorrect criteria, we risk underestimating the severity of patients who actually have COPD,” she added.
Body proportions matter

Professor Arnulf Langhammer, the other Norwegian researcher behind the Lancet article, reminds that Asians and Africans have 8 to 12 per cent lower expected lung capacity than Europeans. This is not because their lungs function less well, but because their chest is smaller in relation to their body height. This is also something that health services must be aware of.

“The increase in lung capacity from cohort to cohort has not been large. But over many years, the increase has become clear. Consequently, we need to update reference values, so we can make precise diagnoses and get a good sense of the severity of any disease,” Langhammer said.
Improvements flatten out

In recent years, researchers have seen that improvements in people's lung capacity have begun to flatten out.

Lung function continues to improve year by year, but not as much as in previous years. Two possible explanations for this may be that a growing proportion of the population is obese and that people are less active in their daily lives.

The study has been part of the European Lung Association's research collaboration CADSET. Researchers from Belgium, Denmark, the Netherlands, Norway, Spain, the United Kingdom, Sweden and Austria participated.


Thursday, December 30, 2021

Archaeology: How nits are revealing secrets about ancient humans


Yes, studying the remains of hair lice is revealing secrets about the DNA of ancient humans.

Scientists studying mummified remains from South America from around 1,500-2,000 years ago, say they have recovered ancient human DNA from the cement that head lice use to stick their eggs to hair.

This cement is made when lice attach eggs, known as nits, to the hair, and at the same time, some skin cells from the scalp also become trapped in the glue-like sticky stuff.

"In addition to genetics, lice biology can provide valuable clues about how people lived and died thousands of years ago," Dr Perotti, Associate Professor in Invertebrate Biology at the University of Reading, explained.

Until now, archaeologists usually extracted ancient DNA from the bones of the skull, or from teeth, as these provide the best quality samples.

However, skull and teeth remains aren't always available, and it can also be against cultural beliefs to take samples from indigenous early remains.

Also the team found the nit glue yielded the same amount of human DNA as found in a tooth, and twice that found in the skull bones.

In the new study, published in the journal Molecular Biology and Evolution, researchers extracted DNA from nit cement on mummified remains of people who reached the Andes mountains of the San Juan province in central west Argentina.

Scientists also studied ancient nits on human hair used in textile from Chile as well as nits from a shrunken head originating from the ancient Jivaroan people of Amazonian Ecuador.

Using the new method, researchers found a genetic link between three of the mummies and other human remains, showing for the first time that the original population of the San Juan province migrated from the land and rainforests of the Amazon in the north of the continent, south of current Venezuela and Colombia.

** Like the fictional story of mosquitoes encased in amber in the film Jurassic Park, carrying the DNA of the dinosaur host, we have shown that our genetic information can be preserved by the sticky substance produced by head lice on our hair.**

Alejandra Perotti , University of Reading

Dr Perotti said that more researchers are looking into migration and diversity in ancient human populations.

"Head lice have accompanied humans throughout their entire existence, so this new method could open the door to a goldmine of information about our ancestors, while preserving unique specimens," Dr Perotti said.

Source:- +

Monday, December 27, 2021

Do Video Games Damage Your Mental Health? Research Reveals Complicated Truth

Fears about what video games are doing to young minds have been growing for years — not least because now 97% of teenagers play them.

They’re said to reduce socialising with real friends, damage psychological adjustment and the violence depicted in many games may be corrupting.

On the other hand, some studies have suggested benefits like improved thinking skills, hand-eye co-ordination, perhaps even greater attention and creativity.

What should parents — and society at large — make of all this conflicting talk?
Cautiously positive

Now a study, conducted by Oxford University psychologist Dr Andrew Przybylski, of almost 5,000 young people in the UK has looked at both the positive and negative effects of video games together (Przybylski, 2014).

The results, published in the journal Pediatrics, are cautiously positive about video games, but still support the old saying: everything in moderation.

Across the children, who were between 10- and 15-years-old, the results showed that the best adjusted children did play video games, but usually for less than one hour a day.

These children were most likely to report:

Being more sociable.

Being more satisfied with their lives.

Having low levels of hyperactivity.

Doing worse on these measures were teens that didn’t play any video games and those who spent at least half of their daily free time on video games (over 3 hours).

For moderate players of video games — those who indulged for somewhere between 1 and 3 hours a day — there were no positive or negative effects on their psychological adjustment.

However, even the negative effects of playing video games too much were relatively insignificant compared to the effects of material deprivation or family conflict.

Dr Andrew Przybylski explained:

“These results support recent laboratory-based experiments that have identified the downsides to playing electronic games.

However, high levels of video game-playing appear to be only weakly linked to children’s behavioural problems in the real world.

Likewise, the small, positive effects we observed for low levels of play on electronic games do not support the idea that video games on their own can help children develop in an increasingly digital world.”

By the same token, there was little evidence that playing video games was doing children that much good.

Przybylski continued:

“Some of the positive effects identified in past gaming research were mirrored in these data but the effects were quite small, suggesting that any benefits may be limited to a narrow range of action games.”

So, despite all the worry and hype, this study at least suggests the effects of video games on teenagers’ psychological adjustment are relatively neutral.

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