Education plays a greater role than age in cognitive test performance among participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

INTRODUCTION: Brazil has gone through very rapid demographic, epidemiologic and nutritional transitions and, despite recent improvements in wealth distribution, continues to present high social and economic inequalities. The ELSA–Brasil is a cohort study, aimed at investigating cardiovascular diseases and diabetes and offers a great opportunity to assess cognitive decline in this aging population through time-sequential analyses drawn from the same battery of tests over time. The purpose of this study is to analyze the influence of sex, age and education on cognitive tests performance of the participants at baseline.

METHODS: Analyses pertain to 14,598 participants with ages 35 to 74 years, who were functionally independent and had no history of stroke or use of neuroleptics, anticonvulsants, anticholinesterase or antiparkinsonian agents. Mean age was 52.1 + 9.1 years, 52.4% were women. Cognitive tests included the word memory tests (retention, recall and recognition), verbal fluency tests (VFT, animals and letter F) and Trail Making Test B. Multivariable linear regression analysis was used to determine the influence of socio-demographic characteristics on the distribution of the final score of each test.

RESULTS: Women had significant slightly higher scores than men in all memory tests and VFT, but took more time to perform Trail B. Reduced performance in all tests was seen with increasing age and , more importantly, with decreasing level of education. For instance, the word list and VFT scores decreased at about one word for every 10 years of age; whereas higher-educated participants scored four words more on the word list test, and six or seven more correct words on VFT, when compared to lower-educated participants. Additionally, the oldest and less educated participants showed significant lower response rates in all tests.

CONCLUSIONS: Age and education influenced cognitive tests performance, but it is noteworthy the higher influence of education than age in this Brazilian population. This highlights the need to develop cognitive tests which are less influenced by education, mainly when studying populations from the developing countries.