What's the secret to happiness as you grow older? A new study suggests that during difficult changes as you age, an acceptance of what can't be changed may be a major predictor of life satisfaction.

A team of researchers from Deakin University in Australia examined levels of life satisfaction and perceived control in 101 older adults living in a residential care facility, and another 101 older adults who lived independently in the same community. Researchers scored life satisfaction based on eight key domains -- standard of living, health, achievement, relationships, safety, connection to a community, future security, and spirituality and religion.

The study defined "perceived control" as a primary control relating to the capacity to make changes to your environment as you like, and a secondary control relating to changes within yourself to adapt to your environment. The components were found to be equally important, and secondary control especially helped subjects living in the residential care facility cope with losses in primary control -- of their home or independence. Also, acceptance -- secondary perceived control -- was found to be more important to the well-being of this group, the researchers wrote.

"In order to protect the well-being of older individuals, adaptation involves both a sense of control and the active acceptance of what cannot be changed," the study's authors said. "Primary and secondary perceived control may predict satisfaction with comparable strength depending on the older person's situation. Acceptance takes more of a prime position in low control situations."

The findings, announced last week, appear online in the Journal of Happiness Studies.

Previous research has also found that people tend to become happier as they age, with a happiness hitting a global average low point at age 46 and increasing after that.

Access the new study: http://link.springer.com/article/10.1007%2Fs10902-013-9452-9