A study published in Nature Communications puts a number on the health cost of loneliness and social isolation. Researchers at Tulane University analyzed data from 277,489 adults aged 40 to 69 who were free of seven major chronic conditions at the start. Using age 50 as a reference, they estimated how many years of life without physical disease or mental disorders were associated with loneliness, social isolation, or both.
The toll was largest for mental health. Men who experienced both loneliness and social isolation lived about 5.8 fewer years free of depression and anxiety, while women lost roughly 3.7 years. The effect on physical health was smaller but still significant: women lost 2.4 years free of physical disease and men lost 1.7 years. Lead author Lu Qi noted that men appear more susceptible to loneliness, and that gender differences in longevity and disease risk may play a role.
The study also found that healthy habits—such as better diet, regular exercise, sufficient sleep, and not smoking—reduced the loss of disease-free years linked to social isolation. However, a healthier lifestyle did not significantly reduce the additional risks associated with feeling lonely. That distinction, the authors say, suggests loneliness and social isolation may require different public health approaches.