Building and maintaining relationships with family and friends, and not just our spouse, keeps us alive longer, even when we're very old. A study of elderly Danish twins shows that survival beyond the age of 75 is extended by having a spouse and other close ties, although the frequency of contact with friends and the other twin is significant only for women and identical twins. Being married enhances survival, and frequent contact with friends is more critical than contact with children (Gerontologist 2005;45: 601-8).

Survivors of coronary artery bypass grafting often seem to experience cognitive decline within five years of surgery, but it's not clear if this is caused by the surgery. A population-based case-control study suggests that grafting is not a major risk factor for dementia or Alzheimer's disease (Neurology 2005;65: 986-90). Another study in the same issue found that the groups with coronary heart disease had lower cognitive test scores at baseline than controls with healthy hearts. Furthermore, the cognitive test performance of patients who had bypass grafting did not differ from that of other groups with heart disease over one year. The trick is to use …