Having good relationships with friends and family members could be the key to a long life.

A report from Brigham Young University finds that people who have strong social relationships are 50-percent less likely to die prematurely than people without a social support system.

The Brigham Young team concluded that having low levels of social interaction can be as damaging to someone's health as smoking up to 15 cigarettes a day or being an alcoholic, and can be twice as harmful as being obese.

Researchers also found evidence that Americans are becoming more socially isolated..

The study is published online in the journal "PLoS Medicine."