Loneliness saps pensioners' brainpower, a study has found.
Elderly men and women with solitary lives suffered more age-related mental decline than those who enjoyed lots of company, an Alzheimer's conference heard.
With millions of people aged over 65 chronically lonely, and many not even speaking to someone every day, experts said it is important that we offer companionship to those in need.
Previous research has shown that social isolation is more damaging than not exercising - and twice as harmful as obesity. The latest study, by Harvard Medical School in Boston, shows the effect of loneliness on the mind. Researchers put more than 8,000 men and women aged 65 and over through tests, including ones to measure mental sharpness, every two years for 12 years. Seventeen per cent admitted to being lonely at the start of the study.
Although the mind would be expected to slow down with age, the effect was accelerated by 20 per cent in the loneliest people, the Alzheimer's Association International Conference in Washington DC heard.