Certain psychological factors such as quick thinking and feeling healthy may be very strong predictors of how long we will live, a new study has found.
Researchers from University of Geneva in Switzerland and University of Oxford in the UK examined 29 years' worth of data collected from 6,203 adults who ranged in age from 41 to 96 years old when they began the study.
Aggregating data from 15 different tasks, researchers looked at participants' cognitive performance across five domains of ability - crystallised intelligence, fluid intelligence, verbal memory, visual memory, and processing speed.
The tasks - all well-established measures of cognitive ability - were administered up to four times over a 12-year period, allowing researchers to assess participants' baseline performance and change in performance over time for each domain.
To gauge participants' health, researchers used the Cornell Medical Index, a measure that includes detailed checklists of a total of 195 pathological symptoms related to physical and psychological disorders.
Finally, the researchers looked at participants' subjective reports of various lifestyle factors, including perceived health, number of prescribed medicines, sleep patterns, hobbies, leisure activities, and social interactions.
Using two types of statistical analysis, researchers were able to assess the relative importance of a total of 65 different variables in predicting participants' mortality risk.
The results showed subjective health and mental processing speed to be two of the strongest predictors - that is, better perceived health and smaller decreases in processing speed over time were associated with reduced mortality risk.
Being a woman was also associated with reduced mortality risk, while years of smoking tobacco was linked with an increased risk of early death.
"Our study shows that two psychological variables, lower self-rated health and age-related decrements in processing speed, appear to be especially important indicators of elevated mortality risk in middle-age and older adults," said Stephen Aichele from the University of Geneva.
"This information may facilitate diagnostic accuracy and timely interventions," said Aichele.
The findings may provide useful insights to health professionals, who need better methods for identifying individuals at risk of early death, researchers said.
The findings were published in the journal Psychological Science.
