Living past 90: Caffeine, alcohol and extra weight may be good for you
Some Americans are living far longer than the average lifespan of 78-and-a-half years. "60 Minutes" correspondent Lesley Stahl reports on new research that shows the surprising factors involved in what may add years to your life. Also, Dr. Claudia Kawas, professor of neurology at University of California, Irvine -- who was featured in Stahl's report -- discusses her research on aging.