The idea that loneliness leads to certain health conditions is now being called into question. Although with a range of negative physical health outcomes, including an increased risk of premature death, it might just be correlated with many of the conditions it was previously assumed to cause.

“Loneliness seems to act as more of an indicator of disease rather than a direct cause,” says at Guangzhou Medical University. “Instead, socioeconomic factors, lifestyle choices and genetic predisposition might be driving risk for diseases like diabetes and heart diseases.”

Social connection is essential to our mental health and ability to thrive. Yet loneliness – the painful feeling that arises from social disconnection – affects a growing number of people around the world.

To learn more about how this affects health, Zhang and his colleagues analysed data from several biomedical databases, including the medical information of 476,100 people in the UK, 16,000 in China and 14,000 in the US. They found that participants who reported feelings of loneliness were at a higher risk of 30 out of 56 individual conditions, ranging from cancers to digestive system conditions.

Then the researchers performed a second round of statistical analysis on 26 of those 30 conditions, focusing on the subset of participants whose genetic data was available. The results revealed that most of the conditions were not, in fact, caused by loneliness. These health problems, including cardiovascular disease, obesity and type 2 diabetes, merely occurred alongside loneliness. But loneliness could still potentially play some role in causing six of the conditions: depression, hypothyroidism, asthma, sleep apnea, substance abuse and hearing loss.

According to , also at Guangzhou Medical University, the findings have important implications for real-world interventions. “Addressing loneliness is important, but it’s not the only factor in preventing diseases,” she says. “Public health authorities should also focus on improving mental health services and promoting healthy lifestyles.”

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at the University of Arizona says the new study “should give us pause in how we think about the public health goals of reducing loneliness to improve human health”.

“To be sure, loneliness itself is highly aversive and seems to be causally associated with the emergence of depressive episodes, but in terms of the connection to health, some of the most cherished findings in the field need to be reconsidered,” says Sbarra. “It is important to understand where the causal effects might exist and where the correlations seem to exist.”

Zhang, He and their colleagues are planning to investigate the underlying biological mechanisms behind their findings, including how loneliness affects things like stress hormones and inflammation. They also hope to run studies on groups of people from other parts of the world to see if their current findings – which are predominately based on data from people in the UK – hold up.

Sbarra adds that, to truly determine whether loneliness causes certain conditions, researchers will need to study whether having better social connection leads to health improvements. “Obviously, any intervention studies showing that you can improve health markers by reducing loneliness would be truly remarkable,” he says. “We have very few examples suggesting this is indeed possible.”

“It is better if doctors don’t get involved since their time can be better spent elsewhere“

Rhino poaching is pushing the species to the brink of extinction (Image: Pete Oxford/Minden Pictures/Corbis)

Can 3D printing save the rhino? Seattle-based bioengineering start-up Pembient believes it can. The company plans to flood the market with synthetic 3D printed rhino horn in an effort to stem the number of rhinos killed for their horns.

But conservationists fear that the plan may backfire, undermining their own efforts to cut the demand for such products in China and Vietnam, the main black markets for rhino horns. They sell for up to $60,000 per kilogram and are used in traditional Chinese medicine and, more recently, as cancer “treatments” and aphrodisiacs.

Rhino poaching since 2007, pushing the species to the brink of extinction. A record 1215 animals were slaughtered last year in South Africa alone.

Conservation organisations and governments have struggled to make a dent in the illegal trade, focusing instead on curbing consumer demand, strengthening anti-trafficking and poaching laws and ramping up on-the-ground protection for wildlife.

But Pembient argues that there is no need to curb demand. “This is something people want, and we have the technology to make it available to them,” says Pembient co-founder and CEO . “Why not try to satisfy their needs instead of telling them their needs are wrong?”

Bioengineered rhino horn smells and feels like the real thing (Image: Pembient)

The company plans to unveil a prototype horn next month. The synthetic horn is based on a largely keratin-based powder with the same spectrographic signature as rhino horn.

Markus says Vietnamese rhino horn users who sampled the fake powder said it had a similar smell and feel to horns taken from wild rhinos.

If all goes well, faux horns could be on sale by next Autumn, at one-tenth of the price of illegal ones. Markus says that the legal product would eventually displace black market horns because it is cheaper, it would be legal, and guaranteed to be unadulterated with cutting agents like water buffalo horn.

The company also hopes to synthesise ivory, tiger bone, pangolin scales and other wildlife products.

“We think all animals are precious, that all traditions are important, and we’re trying to bioengineer harmony between those things,” Markus says.

Easy smokescreen

But conservationists are not convinced. “The road to hell is paved with good intentions,” says , senior director of TRAFFIC, a wildlife trade monitoring network. “My hat’s off to these guys for sticking their necks out and trying to do something, but they should sit down with the people in the country who are experts on consumers and talk these things through, because this could really backfire.”

, founder of Save Vietnam’s Wildlife, says that synthetic rhino horn “is a terrible idea” because it would serve as an easy smokescreen for illegal horn. It also risks stimulating demand by making that product more readily available and implicitly endorsing its value, which undermines efforts to educate horn users.

, technical advisor at Education for Nature – Vietnam, points out that Pembient overlooks the fact that people also use rhino horn for its role as a status symbol. Indeed, in a survey of 500 Vietnamese rhino horn users commissioned by Pembient, only 45 per cent said they would be willing to use a lab-made substitute.

“The synthetic horns will not have an impact on current rhino horn users that want real horns from dead rhinos,” Hendrie says.

“It’s hard to say how this would play out, but at this point, rhinos cannot afford the risk – there are too few of them,” Allan says. “Any miscalculation could cause even greater problems down the line.”