Abstract
OBJECTIVE – The aim of our study was to quantify the importance of the effect of age, sex and education on four transversal measures of cognitive function in an elderly population age from 45 to 75. METHODS – Cognitive functions were assessed in 25,748 volunteers (45 to 75-years-old) included in the French CONSTANCES cohort between January 2012 and May 2014, using (1) the Free and Cued Selective Reminding Test (FCSRT, “immediate” and “delayed” free recall scores), (2) Verbal Fluency Tasks (semantic and phonemic), (3) the Digit Symbol Substitution Test (DSST) and (4) Trail Making Test (TMT, parts A and B). The importance of the associations was quantified using ω2 coefficient representing the percentage of variation of cognitive scores which can be explained by age, sex and education level. RESULTS – Age explained 0.6% of the variation of the scores of verbal fluency, this proportion reached 8.1% for the TMT-A. Sex was reported for 6.3% and 5.0% of the variation of the two scores of the FCSRT, 2.5% of those of the DSST and 0.7% of those of the phonemic fluency. The level of education explained 1.8% of the variation of the TMT-A, the proportion reached 11.5% for the DSST. Finally, age, sex and education considered simulta-neously explained from 8% (for semantic fluency) to 24% (for DSST) of the variations of cognitive scores. CONCLUSION – Age, sex and education are strongly associated with cognitive performance.