Vivek Murthy, the US surgeon general, recently warned that “being socially disconnected” has a similar effect on mortality as smoking up to 15 cigarettes a day. This statement was widely reported in the media, including in the Washington Post, the Times and the Daily Mail. But where does this “15 cigarettes a day” figure come from?
Dr Murthy is referring to a study published in 2010 that explored social relationships and mortality rates. The researchers combined the data from 148 studies on the topic, in what is known as a “meta-analysis”, to arrive at a more robust statistical answer to their questions.
The meta-analysis contained data on 300,000 participants who were studied for an average of seven and a half years. The researchers explored the extent to which social relationships can influence the risk of premature death, the aspects of social relationships that are most likely to predict an early death, and any factors that mitigate the risk.
They concluded that lonely people are 50% more likely to die prematurely than people with strong social relationships. They then used a statistical tool called “random effects models” to compute that the influence of social relationships on the risk of death is comparable to well-established risk factors for death, such as smoking cigarettes.
Although the methodology the researchers used was sound – and loneliness is certainly damaging for health – it could be argued that the “equivalent to 15 cigarettes a day” analogy is sensationalist.
The researchers also pointed out that the health risks of loneliness are similar to alcohol consumption (more than six drinks a day) and exceed other risk factors, such as physical inactivity and obesity. Yet these comparisons are rarely mentioned in the media or keynote speeches as they don’t have the same impact as smoking.
The smoking comparison also has the potential to add to the burden of people who feel lonely and exacerbate the stigma associated with loneliness. However, the effectiveness of the analogy cannot be underestimated. Thirteen years on, the paper continues to raise awareness about loneliness and the associated damaging health consequences.
Studies that didn’t grab the headlines
Other studies that are just as robust, but perhaps fail to grab the headlines in the same way, have likewise shown a range of health conditions associated with loneliness and social isolation, including heart disease and stroke, type 2 diabetes, rheumatoid arthritis and cancer. Even recovery following heart surgery can be compromised by isolation.
Mental health conditions can also be triggered by loneliness, including loss of hope, depression, problems with sleep, alcohol abuse and other psychiatric disorders. Lonely people also have heightened sensitivity to social threat. It is believed loneliness has an evolutionary function that is felt in a similar way to hunger or thirst and is a signal to people to change their lifestyle and social connections. However, when loneliness becomes chronic it can be different to break out of and for people to know how to overcome the negative feelings they are experiencing.
Loneliness is also associated with an increased risk of developing dementia.
The number of people experiencing loneliness increased sharply during the pandemic, including among young adults. The pandemic also accelerated societal transformations, such as remote working and online shopping, that have exacerbated the loneliness epidemic.
The need to address loneliness is further heightened by its costs to health services, businesses and economies. The annual cost of loneliness to the UK economy and UK private sector employers could be as high as £32 billion and £2.5 billion respectively.
So, while Dr Murthy is correct – loneliness can harm your health as much as smoking – there are also many other ways of measuring its harmful impacts.
Andrea Wigfield has received funding from a range of organisations for her work on loneliness including National Lottery Community Fund, Leeds Older People’s Forum, Leeds City Council, Unilever, British Red Cross, Co-operative Society, Age UK.
Jan Gurung and Laura Makey do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
