Living alone linked to higher mortality, with a stronger signal in under-65s

Adults aged 18 to 64 who live alone have a 22% higher overall risk of death than those who live with others, according to a study in the International Journal of Epidemiology. Among people aged 65 and over, the increase was 6%. The authors, led by Hyunjung Lee of the American Cancer Society, say much of the excess risk is tied to health behaviours and existing conditions rather than to living alone in itself.

Data and design

The team analysed records for more than 598,000 American adults. Health information came from nationally representative federal surveys and was linked to death indexes covering 1998 to 2018. This allowed the researchers to estimate how living alone related to death from any cause and to death from 15 specific causes.

The work is set against a long-term social shift. In the United States, the share of people living alone rose from 7.6% (9.4 million) in 1967 to 14.8% (38.1 million) in 2023, so the health profile of this group affects a growing population.

Differences between age groups

In the 18 to 64 group, living alone was linked to the highest relative risk of death from suicide, heart disease, diabetes, colon cancer and injuries. The risk of death from stroke and other cerebrovascular disease was 23% higher. The source summary does not give figures for the other causes in this age band.

Among those aged 65 and older, the strongest associations were with suicide, high blood pressure, injuries and heart disease. Suicide stood out, with a 103% higher risk, followed by high blood pressure (28%), injuries (16%) and heart disease (11%).

What may explain the gap

The authors found that differences in lifestyle, access to healthcare and other health-related factors accounted for a large share of the excess mortality. These factors explained 57% of the difference in overall risk in the younger group and 85% in the older group. Adjusting for them therefore narrowed the gap substantially, especially among seniors.

The team points to several candidate mechanisms. People living alone, particularly men, middle-aged adults and non-Hispanic white adults, were more likely to smoke and to drink heavily. Living alone has also been associated with a diet higher in salt and lower in nutritional quality, and with fewer visits to doctors or routine health checks. According to Lee, the excess deaths are concentrated among people who already have health conditions or high-risk exposures.

Interpreting the findings

This is an observational study, so it identifies associations rather than proving that living alone causes early death. The authors stress that living alone is not inherently harmful. A remaining share of the excess risk, particularly the 43% unexplained in younger adults, suggests other factors are at work, though the source does not say what they might be. Survey-based measures of behaviour and health access are also likely to capture these factors only imperfectly.

For epidemiologists, the results suggest that social isolation research, which has often centred on older people, should give more attention to younger and middle-aged adults. They also illustrate how much of a social risk factor's apparent effect can run through modifiable behaviours and care access.

Implications for practice and policy

The authors call for clinical and policy measures that target modifiable risks in people who live alone. They name chronic disease management, injury prevention, better access to preventive care and screening for mental health conditions. Identifying who in this group would gain most from support, Lee said, is the next practical step. Further work could test whether interventions on diet, smoking, alcohol use and healthcare engagement reduce the excess mortality, and could examine the causes of death that showed the largest relative differences.

Source: Living alone riskier for young and middle-aged adults than seniors, study indicates (Medical Xpress, 31 October 2026).

Image: AI-generated illustration.