A new study published in the journal Nature Communications suggests that social isolation and loneliness may lead to a loss of up to six years of healthy life expectancy—defined as the number of years a person can live without serious physical or mental illness. The research analyzed data from 277,489 adults aged 40 to 69, none of whom had seven major conditions: diabetes, heart disease, lung disease, dementia, cancer, depression, or anxiety. This healthy life expectancy was measured based on the number of years a person could expect to live without developing any of these conditions. The impact of loneliness and social isolation varied between men and women. In terms of physical health, women who experienced loneliness and social isolation had an average of 2.4 years less healthy life expectancy without physical disease, while men had 1.7 years less. However, the gap in mental health was more pronounced: women who suffered from both loneliness and social isolation had about 3.7 years less healthy life expectancy without mental disorders, while men had about 5.8 years less. Lu Qi, co-first author of the study and a professor at the Celia Scott Weatherhead School of Public and Tropical Medicine at Tulane University, said the findings highlight the significant impact of social isolation and loneliness on healthy life expectancy, affecting both physical and mental health. The study also clarified that although related, loneliness and social isolation are different. Social isolation refers to having little interaction with others or a limited social circle, while loneliness is about the satisfaction with the quality of one’s relationships. A person could be socially active but still feel lonely. Previous research has linked both loneliness and social isolation to higher mortality and various health problems, including type 2 diabetes, heart disease, respiratory diseases, neurodegenerative conditions, cancer, depression, and anxiety. These effects may be linked to factors such as increased stress, poor sleep, and reduced quality of life. However, the exact cause-and-effect relationships remain unclear. Qi noted that differences between men and women might explain some of these findings, as men appear more sensitive to loneliness, and women generally live longer. The study also found that healthier lifestyle habits, such as a balanced diet, regular exercise, good sleep, and not smoking, could reduce the loss of healthy life expectancy linked to social isolation. However, these habits did not seem to affect the impact of loneliness. Qi said the results align with previous research showing that social isolation and loneliness are connected to mortality, especially premature death. These findings may help shape public health strategies, encouraging more social interaction, especially among older adults.