© Kaboompics
October 31, 2026
Marianne Waldenfels
Living alone is often seen as a health risk primarily for older people. But a new study of nearly 600,000 adults reveals a surprising pattern: among 18- to 64-year-olds, the risk of death was 22 percent higher, compared with just six percent among seniors. Researchers investigated what might explain this striking difference.
When people think about the health risks of living alone, they usually picture older adults: a widowed retiree or a senior with no one to look after them. But a new study involving nearly 600,000 adults reveals a surprising pattern: among 18- to 64-year-olds, those living alone had a 22 percent higher risk of death. Among seniors, the difference was just six percent.
Researchers at the American Cancer Society investigated why the association is much stronger among younger and middle-aged adults. Their findings were published in late October 2026 in the International Journal of Epidemiology. The findings are also relevant to Germany, where more than one in five people now lives alone.
The team led by Dr. Hyunjung Lee of the American Cancer Society analyzed data from 598,023 adults in the United States. The study drew on a nationwide health survey conducted between 1998 and 2018, which was linked to the national death registry. This allowed the researchers to determine which participants died in subsequent years and what causes of death were recorded.
The researchers compared people who lived alone with those who shared their home with others, distinguishing between two age groups: 18 to 64 years and 65 years and older. Overall mortality and 15 individual causes of death were examined.
The association was especially pronounced among younger and middle-aged adults for certain causes of death:
Among older adults, living alone was associated most notably with deaths from high blood pressure, heart disease and injuries.
The strongest relative association the researchers found was for suicide. Among 18- to 64-year-olds, those living alone had a 58 percent higher suicide mortality risk; among those over 65, the figure was even higher at 103 percent. Whether living alone itself plays a role, or whether other factors such as mental illness and social hardship are the decisive drivers, cannot be determined from the data.
The researchers explicitly caution against treating living alone as inherently harmful to health. It is not necessarily an inferior way of life, lead author Hyunjung Lee emphasizes. The elevated mortality risk is concentrated primarily among people who already have pre-existing conditions or who engage in health-risky behaviors.
The analysis offers concrete figures to back this up: differences in lifestyle, social circumstances, health status, and access to medical care accounted for approximately 57 percent of the statistical association among 18- to 64-year-olds. Among seniors, the figure was as high as 85 percent.
Smoking and heavy alcohol consumption appear to be particularly relevant. According to the researchers, both are more common among people living alone, especially among men and middle-aged individuals. Earlier studies also suggest that people living alone tend to have poorer diets and make less use of preventive medical care.
Living alone does not, however, necessarily mean loneliness. The study did not examine whether participants had close friendships or a stable social network.
Notably, among younger adults, a larger share of the elevated mortality risk remained unexplained even after accounting for these factors, compared with seniors. The study was unable to identify what additional influences might be at work.
In Germany, the issue affects millions of people. According to figures from the Federal Statistical Office, around 17.3 million people lived alone in 2025. Twenty years ago, the figure was still 14.2 million.
Living alone is no longer just a phenomenon of old age. Among 25- to 34-year-olds, nearly one in three lived alone in 2025. In major cities, the proportion of people living alone across all age groups was just under 26 percent.
The new US study thus shines a light on an age group that has so far received less attention in discussions of the health risks of living alone: people in younger and middle adulthood.
The findings also carry an encouraging message: a considerable share of the increased mortality risk is linked to factors that can, at least in part, be addressed. The authors see particular potential for prevention in the treatment of chronic conditions, preventive care, injury prevention, and mental health.
Make use of preventive checkups and routine appointments: People who live alone need to take it upon themselves to ensure that conditions such as high blood pressure, diabetes, or heart disease are monitored regularly. Statutory health insurance members are entitled to a general health checkup with their primary care physician once between the ages of 18 and 34, and then every three years from age 35 onward.
Review smoking and alcohol consumption: Both behaviors can significantly raise the risk of serious illness. For people living alone in particular, it is worth keeping an eye on habits that can quietly become entrenched over time.
Take social connections and mental health seriously: Regular contact with friends, family, or other trusted people can be a source of real support — even for those who genuinely enjoy living alone. Anyone who notices persistent depressive symptoms should seek medical or psychotherapeutic help early.
For many people, living alone is a conscious choice and is by no means automatically unhealthy. But the study shows that health risks don't begin only in old age. Those who live alone should therefore pay particular attention to preventive care, healthy habits, and social connections — especially in their younger years.
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