The combined effects of apolipoprotein E polymorphism and low-density lipoprotein cholesterol on cognitive performance in young adults.

This study examined the relations of apolipoprotein E (ApoE) genotype and the low-density lipoprotein (LDL) cholesterol level to cognitive performance of 57 randomly selected healthy young adults. From the ongoing population-based study of Cardiovascular Risk in Young Finns, 25 men and 32 women were ApoE genotyped and participated in mental arithmetic and reaction time tasks. In contrast to findings obtained from studies with elderly subjects, ApoE4 polymorphism was associated with better cognitive performance. In addition, LDL cholesterol moderated this association. In the ApoE4 genotype group, low LDL cholesterol was associated with good performance in the mental arithmetic test, whereas for those without ApoE4 genotype, low LDL cholesterol was associated with poor performance. Performance in the reaction time task did not differ between the ApoE groups. In conclusion, assessment of the influence of ApoE on cognitive performance may require taking additional physiological factors, such as the level of cholesterol, into account.