What does loneliness have to do with your health?

You can spend all day around people and still feel like there's no one you can really talk to. Equally, you can live alone and have people you feel close to.

A study of 236,879 people in the UK looked at that difference, and how each experience was linked with physical health. The findings suggest there is a reason to consider both how connected we feel and how much contact we have.

What the researchers found

Loneliness describes feeling that the connection you want is missing. Social isolation describes having limited contact with other people. They can overlap, but counting someone's social plans won't necessarily tell you how lonely they feel.

The researchers followed UK Biobank participants from enrolment between 2006 and 2010 through to 2022. They examined three broad groups of illnesses: cancers and other tumours, metabolic conditions, and circulatory conditions. They also looked at the risk of death, including after a diagnosis.

Feeling lonely had a stronger link with developing circulatory and metabolic conditions. Having limited social contact had a stronger link with death, including after a diagnosis. Neither showed an association with newly diagnosed cancers and other tumours in this analysis.

Both loneliness and isolation were associated with health outcomes. The difference was in how strongly each was linked at different stages. Loneliness was still linked with death after some diagnoses, so the findings don't suggest it stops mattering once someone is ill.

The study can't prove that either caused these outcomes. Health problems can themselves lead someone to withdraw. The researchers adjusted for other factors, but circumstances such as financial difficulty may still affect both health and social contact. Loneliness and isolation were also measured at the start, although people's lives can change considerably over the years.

The researchers didn't test whether a particular kind of support would change the outcomes. The findings describe patterns across a large group, rather than predicting what will happen to any one person.

What support can look like

If you see plenty of people but still feel lonely, it may help to think about who you feel comfortable being honest with. There may be someone you speak to regularly who doesn't know you've been having a difficult time.

For someone dealing with a health concern, support can also be very practical. A lift to an appointment or someone to help write down questions beforehand can make the day easier to manage.

A specific offer can be easier to respond to than 'let me know if you need anything'. Asking whether you can bring dinner on Tuesday gives someone a clear choice. If you're the person who needs help, it's reasonable to be just as specific about what would be useful.

And if you've been feeling lonely, it's worth bringing it up in a conversation with a healthcare professional. You don't need to know whether it's connected to a physical symptom before mentioning it.

Having someone to talk to

At TMRW, clinicians look at blood results alongside how someone has been feeling and what's happening in their life. If sleep has been difficult or everyday routines have become hard to manage, that helps put the results in context.

Those conversations help shape the Better TMRW Plan, which is reviewed by a doctor. Test results inform the recommendations, and a person's circumstances help determine how to put them into practice.

A recommendation might sound straightforward in an appointment and turn out to be difficult to fit into the week. Someone may understand the advice perfectly well but be struggling with work, caring responsibilities or a lack of practical help. Being able to explain that gives a clinician a chance to help work out what to prioritise or adjust.

That's part of the thinking behind TMRW's ongoing appointments and clinical team chat. Members can come back with the question they forgot to ask, talk through a result they didn't understand, or say when something isn't working for them. Those conversations can continue as their health and circumstances change.

Source: Komulainen K et al. (2026). Loneliness and social isolation in transitions to adverse health conditions and mortality: an analysis of data from the UK Biobank study. Journal of Epidemiology and Community Health, 80(4), 237-244.

Read the study