We believed that loneliness was just an emotional problem. Science points out that it is a risk factor for dozens of diseases.

Loneliness is undoubtedly a scourge that is integrated into our society and that on many occasions goes unnoticed, especially affecting older people who are practically confined to being at home and with little social contact. And although this is something that a priori can remain in the psychological fieldthe reality is that loneliness emerges as a major public health threat as it is related to very serious diseases.

A big risk. When we talk about risk factors in the field of medicine, we immediately think about nutrition or lack of exercise that are related to very serious diseases. But loneliness must also be added to this entire list, since numerous studies have found a direct association with cardiovascular, neurological and metabolic pathologies, although unraveling the exact cause continues to be one of the great challenges of current medical literature.

The problem. In 2023, the United States Surgeon General public a devastating report pointing out that we were facing an “epidemic of loneliness and isolation.” And it was not a mere poetic metaphor, since the WHO has been warning that social disconnection not only affects us emotionally, but also alters our body to the point of increasing the risk of heart disease, stroke, depression, dementia and premature death.

A measurable impact. When we talk about disease risk, cardiovascular health is the first to suffer. Here, a scientific statement from the American Heart Association, published in it Journal of the American Heart Associationconcluded bluntly that loneliness and social isolation are independent risk factors for poorer heart and brain health.

And the percentages are not anecdotal, since a meta-analysis pointed out that loneliness or social isolation is associated with a 29% increase in the risk of suffering from coronary heart disease and a 32% increase in the risk of stroke.

It goes further. A massive analysis led by the Autonomous University of Madrid in 2026, after following more than 400,000 peopleconfirmed a strong association between isolation and multimorbidity, highlighting that physical social isolation is a relevant risk factor even if the person does not subjectively perceive that loneliness.

The case of dementia. Among dementias, the most important disease is undoubtedly Alzheimer’s and the data are clear in pointing out that unwanted loneliness is an important risk factor for all dementias. Among the reasons that exist, the Alzheimer Center of Barcelona points out in a recent note as follows:

“The relationship between isolation and cognitive decline is supported by research showing how a lack of social interaction impoverishes vocabulary, reduces cognitive flexibility, and accelerates brain decline.”

Here the advice given to be less likely to suffer from this disease when you reach a risk age is to participate in group activities, take advantage of technology to maintain contact or create a social routine.

In mental health. In addition to the organic section, if we move on to mental illnesses, the fact that there is no adequate social support network also leads to an increase in the probability of illnesses as important as depression or even the schizophrenia. Many causes can influence here, such as genetic factors, but in the end a cluster of situations can generate the final trigger for the disease.

The great nuance. The question we must ask ourselves here is the following: do we get sick because of the biological impact of disconnection, or because loneliness is accompanied by other conditions? And here the science suggests that isolated people tend to do less physical activity, have poorer diets and have a greater propensity for smoking or alcoholism. Factors that can trigger a whole battery of serious diseases.

Even with these factors in the equation, loneliness demonstrates surprising predictive strength. For example, recent research in patients with diabetes revealed that loneliness was associated with a greater probability of suffering from coronary heart disease, even outweighing several classic risk factors.

Images | Anthony Tran

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