A study of 277,489 adults found that loneliness and social isolation were associated with fewer years free from major mental and physical diseases. The participants were 40 to 69 years old and had none of seven conditions at the study’s start: diabetes, heart disease, lung disease, dementia, cancer, depression or anxiety.
The strongest differences involved mental health.
The study distinguished social isolation, defined as an objective lack of social connections, from loneliness, which reflects dissatisfaction with the quality of relationships. A healthier lifestyle did not significantly reduce the additional health risks associated with loneliness, suggesting that the two experiences may not affect health in identical ways.