WHY do some widows and widowers quickly follow their spouses to the grave? It seems the so-called widowhood effect could be caused by the combined effects of stress and age-related changes in the immune system.

Previous studies found that among elderly men and women the risk of dying within three months of being widowed increases between 30 and 90 per cent. It had been suggested that this might be connected with changes in the immune system, yet exactly how was unclear.

Now new research has identified some of those changes, and shown that increased cortisol levels caused by stressful events …