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Older adults may not necessarily be at risk for surgery complications just because of their age, but their risk for serious complications may be at least doubled if they are frail or suffering from dementia, a research review suggests. 

The study team examined data from 44 studies of postoperative complications among almost 13,000 patients and found that, overall, about one in four elderly people experienced complications after surgery. 

Even though surgeons often consider age when assessing elderly patients’ odds of postoperative complications, age did not appear to influence the risk, the study found. But factors like frailty, dementia, depression and smoking were all tied to a higher risk of complications for older surgical patients. 

“Frailty and cognitive impairment are geriatric syndromes, whereas age is merely a reflection of how long someone has been alive,” said lead study author Dr Jennifer Watt, a geriatrician at the University of Toronto and the Li Ka Shing Knowledge Institute of St Michael’s Hospital. 

“Many people have had the experience of knowing two older adults of similar age, but recognising that one of those older adults is very robust, spending their typical day exercising at the gym, visiting with friends, and completing a challenging Sudoku puzzle on their iPad; while the other is more frail, spending their typical day at home, needing help to cook meals because they get short of breath from heart failure, and struggling to remember medical appointments,” Watt said by e-mail. 

Geriatric syndromes like frailty and cognitive impairment were associated with higher odds of complications like pneumonia, infections and blood clots, the researchers report in BMC Medicine. 

Frailty in particular was also associated with longer hospital stays, especially among frail patients who also experienced postoperative complications. 

In addition, frailty was linked to a greater chance that patients would be moved to another hospital or to a nursing home or another type of institutional setting and not discharged to their own home. 

One limitation of the analysis is that many of the smaller studies used varied methods to look at the relationship between age and complications after surgery, making it difficult for researchers to calculate meaningful differences in outcomes based on specific risk factors. 

Even so, the findings highlight a need for surgeons to assess elderly patients’ risk of complications using a more nuanced approach that considers how well they function in daily life, said Dr Carolyn Dacey Seib of the UCSF Medical Centre in San Francisco. 

“The most likely reason that age was not an independent predictor of complications is that other geriatric syndromes, such as frailty, cognitive impairment and functional decline, are more representative of a patient’s surgical risk than chronological age,” Seib, who wasn’t involved in the study, said by e-mail. 

“This doesn’t mean that frail or cognitively impaired patients should not ever undergo surgery,” Seib added. “It means they or their decision-makers should be informed of their risk and should be able to make an individualised decision about whether the potential benefit is worth the risk given what is most important to them.”

WASHINGTON — Experts on the forefront of anti-aging medicine say the field is booming, with therapies on the horizon to target illnesses like cancer and Alzheimer’s and make for a healthier, older population in the years to come.

Such remedies are increasingly important because of the world’s aging population. Growing old, experts say, is a leading risk factor for most human diseases and a major socioeconomic problem.

“In the last 20 years this field of research on aging has exploded,” said Felipe Sierra, director of the division of aging biology at the US National Institute of Aging.

“We are getting close to having treatments to prevent the illnesses related to aging,” he added.

Much of the research done so far has been on lab animals and simple organisms like worms, which enable researchers to both measure and tweak life expectancy.

For instance, researchers were surprised to learn that by manipulating just 17 genes, which also exist in humans, they could double the life expectancy of a much-studied worm called C. elegans, and even make mice live 60 per cent longer.

Researchers have also found that a major reduction in calorie intake can have the same effect on these genes.

“We know that the accumulation of cellular damage is the cause of many diseases,” said Luigi Fontana, professor of nutritional science at Washington University School of Medicine, St Louis and University of Brescia in Italy.

“But when you go long periods without food, the resulting metabolic changes appear to stimulate autophagy or a natural cleaning out of your body’s damaged cells.”

Restricting calories for long periods often proves “too difficult” for people, said Sierra.

“There are drugs now that can mimic the effects of caloric reduction,” he added.

Promising molecules

Out of 20 molecules tested so far on mice, seven have led to longer lives, he said.

One of the most promising is called rapamycin (sirolimus), an immunosuppressant used to prevent rejection of transplanted organs.

The substance has been shown to prolong the lives of mice by 25 per cent, and produces similar effects on other mammals.

“There are a lot a side effects but this medication is used in extremely sick people,” said Sierra. 

“The interesting thing is that when they tried it in healthy people none of them had side effects,” he added. “It is a kind of miraculous drug.”

Other promising agents to fight aging target cells that are aging and no longer able to divide, by causing them to self-destruct.

Researchers at Mayo Clinic in Minnesota have been able to genetically eliminate these dysfunctional, aging cells in mice.

“It was amazing. The mice lived longer and were in much, much better health,” said Sierra.

Now there are 15 or 20 of these senolytic drugs being tested.

“And I am sure that some of them might work,” said Sierra. 

“So that is why it is an exciting field right now.”

Longer lifespan

According to Juan Carlos Izpisua Belmonte, a geneticist at the Salk Institute in California, the science of anti-aging is making real progress.

“Now we have methods to slow down or even reverse aging,” he said, citing numerous studies including his own research, showing how cells can be preprogrammed to make them more youthful.

A recent study on Amish people showed the powerful effect of a single mutant gene against the ravages of age.

“It is the first mutation discovered in humans that appears to protect against multiple aspects of biological aging,” said Douglas Vaughan, a cardiologist at Northwestern University in Chicago and lead author of the study.

This mutation, responsible for a steep reduction in a protein called PAI-1, is credited for a tendency to be in better health with advancing age.

Amish with the mutation lived to 85 on average — significantly longer than the predicted lifespan of 71 for the overall Amish population.

A molecule simulating this effect has been the focus of a clinical trial in Japan.

“I think we will see several more discoveries related to the basic mechanisms of aging that will be important,” said Vaughan.

“We are already seeing intensive efforts to develop anti-aging drugs,” he added.

“I think within 20 to 30 years there will be one or more drugs that will be available to slow the aging process or prevent aging related diseases.”

The goal is not to live forever, but to help people enjoy a good quality of life for a longer period of time.

“Probably the maximum life span, if you retain your health to enjoy life, as a human being, is still not much more than 100 years old,” he said.

In Jordan’s extraordinary rose-red “Lost City” of Petra, I have just huffed up 700 zigzagging stone-carved steps to the ancient mountaintop High Place of Sacrifice with its sacred altar and goat blood drain. And now, along a dirt trail, I rest in a rug-draped souvenir stall while an octogenarian bedouin woman — who is traditionally clad in a long embroidered madraga dress and grew up in a cave — deftly strings a fragrant necklace of dried cloves to sell me.

Way down below, camels with tasselled bridles emit rumbling, dinosaur like roars while being led by robed bedouin tribesmen whose eyes are rimmed in jet-black kohl liner. Other indigenous bedouins, headscarves atop their flowing ringlets, strangely resemble Johnny Depp’s Jack Sparrow as they trot on donkeys (“you want air-conditioned taxi?”) past monolithic, 2,000-year-old tombs.

Mystical, mind-blowing Petra literally rocks. Around the 1st century BC, the now-extinct Nabataean people ingeniously chiselled the capital of their Arab empire from sheer sandstone cliffs; at times 30,000 inhabitants bustled about the affluent metropolis that was a major trade stopover for incense- and spice-toting camel caravans. Stretching across harsh desert terrain (Petra’s archaeological park encompasses 264 square kilometres), the once-forgotten marvel includes intricate temples; obelisks honouring pagan gods; etchings of snakes, lions and eagles; cave dwellings; a theatre; and more than 600 massive burial chambers, all hewed from soaring rock faces that bewitchingly glow in swirling hues of terra cotta, apricot and blush pink.

“Petra is one of the world’s biggest mysteries,” says Omar, my Jordanian guide with Exodus Travels. “There is no record of history. And 65 per cent of Petra is still underneath our feet, hidden by dust.”

For almost two weeks, I traverse much of Jordan by bus with Exodus, an adventure company that also brings us 16 intrepid voyagers to the less-visited far reaches of this Middle East nation. Petra is Jordan’s primo tourist draw, but elsewhere we are the only ones clambering over archaeological ruins of a mosaic-splashed Roman fort and a Muslim dynasty’s frescoed castles in no man’s land. History mixes with the present — driving through the bleak parched desert, we pass a sprawling Syrian refugee camp housing 36,000 in rows of white shelters; Jordan has taken in about 1 million people who have fled the war-torn nation to its north.

Before joining our group, I spend two days in the vibrant old quarters of capital Amman and clearly stick out — locals repeatedly ask where I am from. This is a Muslim country, and when I say “America”, they all warmly reply, “Welcome to Jordan,” often with their hands placed over their hearts. I am probably welcomed 100 times — in taxis, cafes while I eat mezze plates of hummus and falafel, shops, hookah bars, streets lined with bowing worshipers outside a minaret-topped mosque.

It is the start of a cultural odyssey. With Exodus, I also retrace exploits of Lawrence of Arabia, the dashing British officer who gained fame in World War I for leading the legendary Arab Revolt against the Ottoman Turks. Pre-trip, I rewatched the 1962 Oscar-winning epic “Lawrence of Arabia”, so it’s eerie to stand in the gravely quiet courtyard of Qasr Al Azraq, the storied black basalt fortress where T.E. Lawrence and his bedouin troops plotted attacks during the winter of 1917.

Another day, I am bouncing in the blanketed bed of a bedouin-driven Toyota pickup tearing across the UNESCO-listed Wadi Rum desert, nicknamed “Valley of the Moon” for its rippling peach-pink sands pierced by titan sandstone and granite peaks. Lawrence and his guerrilla rebels made their base here in 1917-18, and decades later director David Lean filmed the cinematic classic in this otherworldly locale. (Planetwise, Wadi Rum also subbed for Mars in the 2015 Oscar nominee “The Martian”.)

Near a commemorative rock carving of Lawrence’s face, we stop at a rectangular tent woven from black goat’s hair and occupied by hospitable bedouins who offer us cardamom-and-sage tea. First, one of them has us stick out our forearms and rolls on a soaplike perfume. “It’s gazelle innards,” Omar says afterwards. Yuck.

Most of the bedouins I meet speak only Arabic, so Omar gladly translates. “He says, ‘You are a camel.’”

A what?

“It means you are beautiful, because camels are beautiful with their long eyelashes.”

I sit my hump down and enjoy the steaming sweet tea, cooked in a charred brass kettle over a rudimentary fire pit. Because Muslims avoid alcohol, tea is a main social drink in Jordan, and you’re constantly offered a cup in friendship. (You’ll find non-alcoholic beers and non-alcoholic wines on some menus, but the rare place I hoist a glass of Cab is outside Petra’s gate at the 2,000-year-old Cave Bar, touted as the world’s oldest saloon. Indeed there are spirits; it’s a former Nabataean family tomb.)

In Wadi Rum, I sleep inside a goat-hair tent in a rustic bedouin camp set against wind-buffeting cliffs on the desert floor until at 4am I am awakened by a distant muezzin’s melodic call to prayer and, after that, a rooster’s shrill cock-a-doodle-doo.

Next I wake up the entire camp shrieking as I clumsily mount my ride. “Yalla, yalla,” Rashid gently urges his herd of five sibling camels, meaning “Let’s go,” and soon with just one other traveller, we have the pre-dawn moonscape to ourselves.

Atop cud-chewing Aliya, I hypnotically watch the flaming sunrise turn the unending vastness a radiant gold. For 90 beyond-belief minutes, the only sounds are the camels’ feet softly sinking into the powdery dunes and the chirping of Sinai rosefinches. A well-fed stray dog joins our pack, funnily bringing up the rear.

Every day of our itinerary, we hit an archaeological treasure. I feel like I’m in Italy as I wander the immense 2,000-year-old Roman city of Jerash, dubbed the “Pompeii of the Middle East” for its well-preserved ruins buried by blown sand for centuries. Cultures humorously collide: Two bedouins, head-scarfed with red-and-white chequered keffiyehs, toot “Yankee Doodle Dandy” on bagpipes in the Corinthian-columned amphitheatre near the chariot hippodrome.

Petra, though, is the jackpot. Abandoned in the seventh century, it was rediscovered by a Swiss explorer in 1812 and became a UNESCO heritage site in 1985. Hidden away, to get to the ancient city, you have to trek through the dramatic narrow Siq, a nearly mile-long slot canyon sandwiched by 24-story-high veiny rock edifices and at times only three metre wide. Nature-created formations stare down in the shapes of elephants and skulls. At the end, the Siq cracks open to reveal the grandstanding, rock-whittled funerary-urn-crowned Treasury, likely a former temple. Harrison Ford galloped up to the fantastical facade in the 1989 movie “Indiana Jones and the Last Crusade” in search of the Holy Grail.

After dark, I return for the corny-cool “Petra by Night” ceremony. Even with my flashlight I can barely see as I stumble through the ghostly Siq, lit only by hundreds of luminaria candles, and then sit in the luminaria-lit dirt in front of the shadowy Treasury. Bedouins play a flute and rababa string instrument before the big reveal — spotlights suddenly bathe the Treasury in changing psychedelic colours.

Over two days I walk 37 kilometres in Petra because the scenes won’t quit. On the High Place of Sacrifice climb, I smell the pungent smoke of juniper branches, and soon a bedouin man is hawking me a morning shot of Arabic coffee heated by a campfire teetering on a killer-view ridge. Later, as my elderly new friend Hammadeh strings that clover necklace in her ramshackle stall, she tells me through interpreter Omar how she once lived in a cave in Petra and still follows the old ways, herding her sheep and goats. Without tourism, she frets, she has no money. “I thank God. I thank God for everything,” she says as I buy three more necklaces.

Petra’s most jaw-dropping high place is the Monastery, accessible by hoofing up nearly 1,000 Nabataean-cut steep steps. After the path’s last bend, this mammoth stone temple — it’s 47 metres wide — magically pops out of a remote mountainside towering over my puny presence. From the monastery, I continue ascending a boulder-strewn trail until next to a grazing grey donkey I see a piece of scrap wood lying against a pile of rubble and hand-scrawled, “Welcome to Top of the World Café.” Up further, I reach the “café”, a tattered, tented platform precariously perched over a rocky ledge in the heavens. And there, a 17-year-old bedouin named Lost (“because you’re always found”, he smiles) offers me another cup of tea, this one with a sprig of mint.

People who consume lots of foods linked to chronic inflammation, such as red meat and refined grains, may be more likely to develop colorectal cancer than individuals who tend to avoid these foods, a US study suggests. 

Researchers examined more than two decades of US survey data on eating habits and cancer diagnoses for 74,246 female nurses and 46,804 male health professionals. They sorted participants into five groups based on how likely it was that their daily diets could contribute to inflammation. 

Compared to people with diets that had the least potential to cause inflammation, individuals with diets that were most likely to cause inflammation were 32 per cent more likely to develop colorectal cancer during the study, researchers report in JAMA Oncology. 

“A dietary pattern that is associated with higher levels of inflammation will chronically stimulate the bowels, leading to the production of a constantly higher level of circulating inflammation mediators that may contribute to the development of cancer,” said lead study author Fred Tabung, a researcher at the Harvard T.H. Chan School of Public Health and Brigham and Women’s Hospital in Boston. 

“Such a pro-inflammatory dietary pattern has a high intake of red meat, processed meat, organ meat, refined grains, and sugary beverages and a low intake of tea, coffee, dark yellow vegetables and green leafy vegetables,” Tabung said by e-mail. 

Men with the most pro-inflammatory diets were 44 per cent more likely to develop colorectal cancer than men with diets that were least likely to cause inflammation, the study found.

Women with the most pro-inflammatory diets were 22 per cent more likely to get colorectal tumours. 

In both men and women, the connection between a pro-inflammatory diet and colorectal cancer risk persisted across all anatomical sites where these tumours can develop, except for the rectum for women. 

The risk of developing colorectal cancer was even higher among overweight or obese men and lean women, and also among men and women who did not consume alcohol. 

Some of the most important risk factors for colorectal cancer are family history, personal history of polyps or cancer, certain diseases such as ulcerative colitis, and not getting screened, previous research has found. Not smoking, maintaining a normal weight and taking aspirin are associated with a lower risk of colon cancer. 

When, a few days ago, I pointed out to this young relative of mine that he had been watching too much TV and that this could harm his eyes, he shocked me with this answer: “Oh no, actually I am watching TV to take a break from playing with my tablet”. It made sense. After all, watching a large screen at a distance of three metres certainly is “safer” than staring at a small tablet held only a few centimetres from your face.

Long gone are the days when the old CRT (Cathode Ray Tube) screens used to affect our eyes with various radiations. LCD and LED displays are significantly safer today. However, the mere fact of having your eyes focusing on a near object for too long is harmful. Especially if this object emits light, like all tablets and smartphones do. And do not try to convince a teenager to take his eyes off his mobile device every few minutes and to look for a few seconds at a distant point out of his window, just to reduce eye strain.

With every year that passes myopia or short-sightedness affects an increasing part of the population. Last year sciencealert.com put it bluntly but clearly in a headline titled: “Half The World’s Population Will Be Short-Sighted by 2050”. The report was very balanced, written scientifically and with restraint. It warned about jumping to hasty conclusions. Briefly, it said that there was no conclusive evidence at this stage that it is only the excessive usage of various computing devices that was to blame, though it may well be the dominant factor. Eating habits and imbalanced intake of essential nutrients probably also play a role.

According to Sarah Zhang (Wired): “Based on a handful of large epidemiological studies on myopia, spending time outdoors — especially in early childhood — reduces the onset of myopia,”

The IT industry is doing what it can to help curb the phenomenon, without however going as far as to tell us not to use the devices or to reduce our Internet browsing time, for example. Again, quality screens such as LED or OLED make a difference here. We are encouraged to read eBooks not using regular tablets but dedicated reading devices such as Amazon Kindle Paperwhite for instance. They are certainly gentler on the eye, but you will still be staring at something kept very close to your face for long hours.

Kindle Paperwhite is as close to a printed book as they can make it — understand as easy on the eyes. So what is the difference between a Kindle and a hard-copy printed book? Why are mobile computing devices more harmful and why would they increase the risk of myopia?

With printed books you just… well, read books! With a mobile digital device, however gentle on your eyesight it may be, you read books, write emails, send messages, check social networks, do your online banking, browse the web and do the million things we got accustomed to doing this way. Hence the steadily increasing number of hours one would spend every day, focusing on a closely kept display.

Several government and private services in Jordan will only be available online as of this year, mainly payments of monthly and annual bills of all kinds, including the municipality tax on property. This means more time spent staring at digital displays of all kinds, every day.

For many years now we have been advised not to remain seated for long, continuous hours, so as to reduce cardiovascular health hazards. With the increasing risk of myopia everywhere in the world, spending more time outside, doing regular physical exercise is more crucial than ever. It is also valid for the heart, the muscles, the bones or the eyesight, not to mention the brain. It is obvious, it is trivial, it is understood, but we keep forgetting it.

To counteract global warming, humans may someday consider spraying sulfur dioxide into the atmosphere to form clouds — and artificially cool the Earth.

The idea behind the process, known as geoengineering, is to keep global warming under control — with the ideal solution still being a reduction in the emissions of greenhouse gases.

However, suddenly stopping that spraying would have a “devastating” global impact on animals and plants, potentially even leading to extinction, according to the first study on the potential biological impacts of climate intervention.

“Rapid warming after stopping geoengineering would be a huge threat to the natural environment and biodiversity,” said study co-author Alan Robock of Rutgers University. “If geoengineering ever stopped abruptly, it would be devastating, so you would have to be sure that it could be stopped gradually, and it is easy to think of scenarios that would prevent that.”

Rapid warming forced animals to move. But even if they could move fast enough, they might not be able find places with enough food to survive, the study said.

“Plants, of course, can’t move reasonably at all. Some animals can move and some can’t,” Robock said.

If stratospheric climate geoengineering is deployed but not sustained, its impacts on species and communities could be far worse than the damage averted.

While animals would be able to adapt to the cooling effects of the spraying, if it is stopped the warming would ramp up too fast for the animals to keep up.

Researchers in the study used computer models to simulate what would happen if geoengineering led to climate cooling and then what would happen if the geoengineering stopped suddenly.

Starting geoengineering then suddenly stopping it is not necessarily far-fetched.

“Imagine large droughts or floods around the world that could be blamed on geoengineering, and demands that it stop. Can we ever risk that?,” Robock said.

The idea behind this type of geoengineering would be to create a sulfuric acid cloud in the upper atmosphere that is similar to what volcanic eruptions produce, Robock said. The clouds, formed after airplanes spray sulfur dioxide, would reflect solar radiation and thereby cool the planet.

Geoengineering takes its cue from the natural experiment that actually had made the only recent dent in global warming’s rise in the last few decades — the 1991 eruption of Mount Pinatubo in the Philippines, which blasted more than 15 million tonnes of sulfur dioxide 33.7km high, straight into the stratosphere.

The stratosphere suspended those sulfur particles in the air worldwide, where the haze they created scattered and reflected sunlight away from the Earth and cooled global atmospheric temperatures nearly -17.2ºC to -17ºC in 1992 and 1993, before finally washing out, according to NASA’s Goddard Institute for Space Studies estimates.

But the airplanes spraying the sulfur dioxide would have to continuously fly into the upper atmosphere to maintain the cloud because it would last only about a year if spraying stopped, Robock said. The airplane-spraying technology may be developed within a decade or two, he added.

As detailed in the 2016 Paris climate change agreement, the world’s nations have pledged to ensure that global warming stays well below 3.6 degree above industrial levels.

This method of geoengineering is one of two primary ways humans could counteract man-made climate change, with the other being trying to remove the carbon dioxide that’s already in the atmosphere.

Both procedures remain theoretical and untested.

LOS ANGELES — Sony’s family film “Jumanji: Welcome to the Jungle” stomped the competition at the North American box office, taking the top spot for the third consecutive weekend, industry figures showed on Monday.

Starring Dwayne “The Rock” Johnson along with funnymen Jack Black and Kevin Hart, the feature netted just over $19.5 million from Friday to Sunday, bringing its total to $316.5 million in its fifth week out, industry tracker Exhibitor Relations reported.

The film follows four teens who find themselves transported inside the Jumanji video game world.

Debuting in second place was “12 Strong” from Warner Bros., starring Chris Hemsworth, about US special forces deployed to Afghanistan after the September 11, 2001 attacks. It had a take of $15.8 million.

Gritty heist thriller “Den of Thieves” from STX Films was third on the list in its debut weekend, with $15.2 million. 

The movie, starring Curtis “50 Cent” Jackson and Gerard Butler, follows the intersecting lives of the major crimes unit of the Los Angeles Sheriff’s Department and an elite band of robbers.

Fox’s “The Post” dropped to fourth place from second, after pulling in $11.7 million over the weekend for a total take of $44.8 million in four weeks.

The political thriller recounts the nail-biting behind-the-scenes story of The Washington Post’s 1971 decision to publish the Pentagon Papers, which exposed the lies behind US involvement in the Vietnam War and helped catapult the newspaper’s standing among the nation’s best.

“The Greatest Showman,” a Fox film about circus impresario P.T. Barnum, netted $10.6 million to take the fifth spot. It has taken in $113.1 million in five weeks.

Rounding out the top 10 were “Paddington 2” ($8 million), “The Commuter” ($6.6 million), “Star Wars: The Last Jedi” ($6.6 million), “Insidious: The Last Key” ($5.9 million) and “Forever My Girl” ($4.2 million).

Weight gain is not just a number on your bathroom scale.

A new Stanford study has found that the entire body undergoes changes for the worse when people pack on the pounds.

Even just a modest weight gain of about three kilogrammes causes bacterial populations to change, immune responses to shift and changes in the molecular pathways associated with heart disease, researchers found. 

“Your body is responding to a very stressful event,” said lead researcher Michael Snyder, a professor of genetics at Stanford.

But here’s the good news: When the weight is lost, the body’s systems return to their natural, healthier state.

A paper describing the study as published in the latest issue of the journal Cell Systems.

“The whole body is engaging,” Snyder said. Weight gain “is a systemic disease, not just affecting your fat, but affecting your whole body. And luckily, it reverses when you lose it”.

The team studied 23 people with body mass indexes of between 25 and 35 kilogrammes per square metre. A BMI of 25 is on the high-end of normal; a BMI of more than 40 roughly equates to morbid obesity.

About half of the people were insulin-resistant or at risk of diabetes. The other half were insulin-sensitive or able to process insulin normally.

From blood samples, they pooled millions of pieces of information from participants’ transcriptome, a collection of molecules that reveal patterns of DNA expression; the proteome, the complete set of proteins that are produced; the microbiome, the microbes that keep us alive; and the genome, or genetic blueprint.

Then participants received a high-calorie diet — about 1,000 extra calories per day for men, 750 for women — and after 30 days they had, on average, tacked on just under 3kg.

“It’s not unlike what a lot of us have just done over the Christmas holiday,” Snyder said. “This is not outside the realm of what normally goes on.”

And with weight gain — moderate though it was — the participant’s underlying biological profiles shifted, too.

“The goal was to characterise what happens during weight gain and loss at a level that no one has ever done before,” Snyder said.

The team also wanted to study the underlying molecular shifts in people at risk of diabetes.

“Most studies look at just one little part of something. It’s like making a jigsaw puzzle by just looking at the edge pieces,” he said. “We are trying to look at the entire puzzle, putting all the pieces together, which lets us see things much better.”

The 17-member Stanford research team included experts with Stanford Bio-X, the Stanford Child Health Research Institute, the Stanford Cancer Institute, the Stanford Neurosciences Institute and the Stanford Cardiovascular Institute. Researchers at the Jackson Laboratory for Genomic Medicine, Yale University, the Royal Institute of Technology, the Chalmers Institute of Technology, the University of Gothenburg and Uppsala University also contributed to the work.

Their analysis revealed a shift in the body’s microbiome, the vast army of microbes that protect us against germs, breaks down food to release energy, produce vitamins and perform other tasks.

Microbial species changed with weight gain, the researchers found. For instance, populations of a bacteria called Akkermansia muciniphila, which is known to protect against insulin resistance, shot up. This is a trend that could help understand the underlying dynamics that lead to diabetes.

Secondly, there was a change in the body’s immune responses. Inflammation flared more in normal people than in those with extra kilogrammes, they found.

With weight gain, “inflammation was a little impaired,” Snyder said. “The immune system is a bit crippled.”

Finally, the molecular pathways associated with heart disease were activated. There was a shift in gene expression associated with increased risk for a type of heart failure called dilated cardiomyopathy, in which the heart cannot pump blood efficiently to the rest of the body.

This might explain, indirectly, why the risk of heart attack climbs with added weight, said Snyder. While the activated pathway is not causing heart issues, “it is a signal of what’s going on”.

Snyder’s advice: “Don’t gain the weight. Exercise, and the food you eat, are absolutely critical.”

Exposure to trees and other greenery has been shown to stave off depression in adults, and a new US study finds the same may be true for teenagers. 

Researchers looked at more than 9,000 kids aged 12 to 18 and found those who lived in areas with lots of natural vegetation nearby were less likely to display high levels of depression symptoms. The effect was strongest among middle schoolers, the study team reports in Journal of Adolescent Health. 

“Prior research has shown that lower exposure to nature is associated with more negative emotional and behavioural outcomes,” lead author Carla Bezold of the Harvard T.H. Chan School of Public Health in Boston said in a telephone interview. 

To see if this is true during the teen years, the researchers analysed data on 9,385 adolescents who began participating in 1999 in a large study of health factors affecting US youth. Participants had mental health assessments and also provided information about substance abuse, environmental safety issues and race in an annual questionnaire. 

Bezold’s team used geo-coding to identify where the participants lived, and satellite data to examine the areas around their homes to assess building density and proximity to green spaces as well as blue spaces — bodies of water. In addition to how close by green and blue spaces were, researchers measured their amount and quality — large and lush or small and sparse. 

Based on the mental health assessments, the researchers found that 11.5 per cent of kids had depression symptoms. They categorised the top 11.5 per cent of that group with the highest levels of depression symptoms as having “high depression”, and looked at how nearby green and blue space influenced whether kids fell into that category. 

“We saw that living in an area that was greener was associated with lower depression among this population,” Bezold said, “and that the association persisted using a number of statistical techniques, which gives us confidence that the association is there and so are the benefits”. 

Overall, after adjusting for family and economic factors, researchers found that young people living amid the highest-quality green space were 11 per cent less likely than peers with the poorest-quality green space to be in the high depression group. No significant association was found for blue spaces, however. 

The mechanisms linking nature and mental health are fascinating to say the least and, not surprisingly, an active area of theoretical study, said Kirsten Beyer, a health geographer at the Medical College of Wisconsin in Milwaukee, who was not involved in the study. 

“The attention restoration theory is just one theory. It argues that nature offers an opportunity to relax our directed attention, thus providing relief from mental fatigue,” Beyer told Reuters Health by e-mail. 

Another possibility is the so-called biophilia hypothesis, she said, which argues that humans have this inherent biological tendency to respond positively to natural environments. 

“There are a number of mechanisms connecting greenness and improved overall health,” Bezold said. “Prior evidence shows that living among higher density vegetation is linked to reduced stress, increased physical activity and improved incidental contact and social interaction between neighbours.” 

Urban planners and public health professionals are talking more and more, Bezold added. “Decisions are now being made… as to how best to structure communities in order to optimise health. Design teams have come to understand the importance of having nature in a residential environment because it promotes community health — in more ways than one. It’s about more than just aesthetics.” 

What about teenagers living in more urban areas where green space is harder to come by? 

“Interestingly, research has shown that even photographs of nature can have positive benefits,” Beyer said. “Greening indoor environments should not be discounted as a way to protect mental health. Even in the most urban environments, vacant lots, yards, and street trees offer opportunities for adding greenspace to the landscape.”