Thanksgiving will soon be here, and many of us will be with family and friends over the holiday, enjoying a meal and time together. And although most of us know that our relationships in life are important, there’s been recent research that further demonstrates how important relationships are to the way we experience life — both in our happiness and in our health.

Last week, I heard an interview with Shawn Achor, author of The Happiness Advantage. In the interview (around the 10:30 mark), he talks about the single greatest predictor we have of long-term happiness. What is it? According to all the research, social connection is the best indicator of long-term happiness we have.

This was clearly visible when he visited many developing countries. Even in the midst of chaos and instability, people there were still optimistic and joyful. And one major factor was the strength of their social relationships. Even though they lacked money and possessions, the one thing they did have was a deep and strong and wide social network. And it was this social connection, Achor posits, that enabled them to go through challenging times with a greater sense of joy and meaning.

Achor goes on to point out that recent research has also shown that social connection is as good of a predictor of how long someone will live as smoking, obesity, or high blood pressure. Meaning, there is a direct correlations between the breadth and strength of our relationships, and our life expectancy.

Both our long-term happiness and our long-term health are deeply connected with the depth and quality of our relationships, providing yet more reasons to be intentional about building and nurturing our relationships.

So as you share a meal with family and friends this coming holiday, remember that your relationships matter — and in more ways than you may realize.