When you were a teenager, your parents probably warned you once or twice not to get a tattoo (文身) just because your friends did it. A new study shows that the influence of friends — for good and for bad — remains in our older years, as well.

The study authors analyzed (分析) surveys from nearly 13,000 over-50-year olds. The study found that those who had high-quality friendships actually lived longer. Those people took the survey three times over eight years and those with the good friends were 24% less likely to die during that time. Having good friends was connected with positive health behaviors and benefits, like a 9% increase in likelihood to exercise, and a 17% lower likelihood of feeling anxious, among other findings.

The dangers of loneliness have become more and more apparent in recent years as one in four older people now experience social isolation (孤立) worldwide, which carries higher risks of anxiety, and other problems, according to the World Health Organization.

Unlike family members, we can choose our friends freely. Think of the stress you might feel at a big family gathering versus the relaxation you might share with your closest friends at a birthday party.

But those effects of friendship that your mom warned you about as a teenager appear to still exist in your later years. Those people in the study with the best friendships were also more likely to smoke and drink heavily.

William Chopik, study co-author, notes this doesn’t encourage people to smoke or drink heavily just because they have friends. “You can generalize these results with great confidence to the population as a whole,” Chopik says. “My future work will dig deeper into these details about friendship. But the nature of friendships remains a powerful public health opportunity. The fact that you can make new friends can improve a lot of different parts of your life.”

My best friend travelled to stay with my family last weekend. When she arrived, she went straight to the kitchen and, without asking, ate some dried fruit. She wasn’t being rude. I knew she would do this. We’ve known each other for almost 20 years. She can eat anything she wants from my kitchen. Indeed, I bought her favourite fruits and snacks at the shop that morning.

Our long weekend together was simple. I was recovering from surgery and couldn’t go to shopping malls. But there were no quiet moments. We’ve lived in different cities for almost a decade. Reunions demand conversation.

Our personalities are matched, to be sure, and a shared history is indescribably (难以形容地)valuable. We were competitors at high school before bonding. Then we discovered the many interests that we had in common. Our friendship developed itself quickly. We stayed companions and supported each other through law school and through our first jobs. Ours is a friendship for the ages.

There is something special about friends who know everything about you. They are rare. They have seen your achievements, your desperation and your boring routine of the in-between. It’s special to unpack feelings without wasting time filling in the blanks. As my long weekend shows, with such friends we don’t have to do well, but we simply have to be ourselves. We drop the act, the performance and the public version of ourselves. The special friendships are those which never fail to delight us, whose continuation is worth the extra effort, despite distance and difference in our separate lives. I had the very great joy of this reminder last weekend. I’m lucky to have found this friend, and to see a future where her companionship remains. Being together is perfection.

My 10-year-old Donna said, “Mom, I made a new friend at school today. Can she come over tomorrow?” Donna was a shy girl and I wanted her to make some friends to bring her out of her shell.

“Sure, honey, that sounds great.” I said, thinking back to my own best friend, Lillian. We lived across the street from each other in Washington Heights, New York. We met at the age of 10, too. Like my daughter, I was shy, but Lillian drew me out. She was one of the friendliest people in school, with shiny black hair and a mile-wide smile.

In senior high school, Lillian went on a trip to Florida. This was the first time we had to be away from each other for a few days. “I’ll be back soon.” she told me. But three days later, Lillian’s sister told me that she had fallen into a river and hadn’t come out any more. Soon, my family moved to New Jersey. Whenever I thought of her, tears came into my eyes.

The next day Donna brought her new friend home. “Hi, Mrs. Loggia.” the little girl said. Her hair was so shiny and black and she shot me a big smile. “My name is Laura.”

My daughter’s new friend was so much like Lillian. I was still puzzled (迷惑) when Laura’s mom came to pick her up later that afternoon. I opened the door to let her in. “Judy!” she cried. “It’s me, Lillian’s sister, from Washington Heights.” Yes, my daughter’s friend looked familiar. She was Lillian’s niece (侄女).