Is there a secret to living well into your 90s?

If there are secrets to living a longer and healthier life, Dr. Claudia Kawas is searching for them.

60 Minutes first met Dr. Kawas, a neurologist and professor at the University of California Irvine, in 2014 when Lesley Stahl interviewed her for a story titled "90+." 

Dr. Kawas and her team run a major study of aging California residents who began providing information about their diet, exercise, vitamins, and activities in 1981. 

"I really believe that when we learn things from the 90-year-olds, they're going to be helping the 60 and 70-year-olds, not just how to become 90-year-olds, but how to do it with style and as good a function as possible," Dr. Kawas told 60 Minutes in 2014. 

The multi-million dollar study, funded by the National Institutes of Health, discovered several factors that were associated with longer life. The study found moderate alcohol consumption of up to two drinks a day led to a 10% to 15% reduced risk of death compared to non-drinkers. It also revealed a caffeine intake equivalent to one to three cups of coffee a day was better than more, or none. 

Last year, Stahl interviewed participants from the original story for a follow-up report that airs this Sunday on 60 Minutes.