Is There an Association between Temperament and Apolipoprotein E? A Replication of a 1993 Young Finns Study

Background: An association between apolipoprotein E (apoE) gene polymorphism and temperament has been found in the Young Finns cohort. Motor activity in childhood and mental vitality, sociability and positive emotionality in adolescence were associated with apoE. Two research groups have attempted to replicate these findings but no associations have been found. Purpose: The purpose of the present study was to confirm the original findings with new and more reliable genotyping from a larger sample derived from the same Young Finns Study as the original finding.Methods: The study included 2808 participants aged 3 - 18 years in 1980. The same methods in assessing temperament were used as in the original study. Temperament was operationalized as motor activity, cooperativeness, negative emotionality, mental vitality, sociability and positive emotionality. Temperament was assessed by participants’ mothers in 1980 and 1983 and self-rated in 1983 by adolescent participants. Results: Motor activity was not associated with apoE polymerphisms. All other previous results were replicated. Adolescents’ positive emotionality, mental vitality and sociability were associated with apoE. Conclusions: The results indicated that there is an association between temperament and apoE. The previous absence of association between temperament and apoE in the replication studies may be due to the fact that researchers used different dimensions of temperament and thus probably studied different phenomena. Cultural differences in personality assessment might also explain the contradictory findings.