Lead author Frieder R. Lang of the University of Erlangen-Nuremberg in Germany, said the findings revealed being overly optimistic in predicting a better future was associated with a greater risk of disability and death within the following decade, the Daily Telegraph reported.
"Pessimism about the future may encourage people to live more carefully, taking health and safety precautions," Lang said in a statement.
The research, based on data collected between 1993 and 2003, asked 40,000 respondents to rate how satisfied they believed they would be in five years time. They were interviewed again five years later, and their satisfaction levels compared with their predictions, Lang said.
The study, published online in the journal Psychology and Aging, found those who overestimated how happy they would be were 9.5 percent more likely to report disabilities, and a 10 percent higher risk of death. In addition, the study found older people, who tended to have a "darker outlook" on the future, were shown to be the most accurate in their predictions, with optimistic youngsters overestimating their success.
"Unexpectedly, we also found that stable and good health and income were associated with expecting a greater decline compared with those in poor health or with low incomes," Lang said. "Moreover, we found that higher income was related to a greater risk of disability."