Angelina R. Sutin of the Florida State University College of Medicine conducted the study while at the National Institute on Aging, part of the National Institutes of Health. Sutin and colleagues used two large-scale longitudinal studies -- the Baltimore Longitudinal Study of Aging and the National Health and Nutrition Examination Survey for those age 30 and older.
Sutin and colleagues looked at data from several thousand people including more than 10,000 reports on well-being, health and other factors.
The researchers found when they analyzed the data across the whole pool of participants, older adults had lower levels of well-being than younger study participants, but when they analyzed the same data while taking into account birth cohort -- people born during the same time period -- a different trend appeared.
Life satisfaction increased over the participants' lifetimes and remained even after factors like health, medication, sex, ethnicity and education were taken into account, Sutin said.
The study, published in the journal Psychological Science, found those born in the early part of the 20th century, who lived through the Great Depression, had substantially a lower level of well-being than cohorts who grew up during more prosperous times.
The greater well-being of more recent cohorts could result from economic prosperity, increased educational opportunities and the expansion of social and public programs in the late 20th century, the study said.
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