Reduced memory in fat mass and obesity-associated allele carriers among older adults with cardiovascular disease.

BACKGROUND: Much attention has been paid to the prevalence and predisposition of the fat mass and obesity-associated (FTO) gene to obesity, although only a few studies have characterized the extent to which this affects cognitive function. This study examined differences between risk allele carriers (i.e. FTO-AC/AA) and non-carriers (i.e. FTO-CC) on indices of attention/executive function/psychomotor speed, memory, language, and visual-spatial ability in a sample of older patients with cardiovascular disease.
METHODS: We recruited 120 older adults from an outpatient cardiology clinic who underwent blood draw and completed neuropsychological testing. Participants were classified into two groups: one for those who were homozygous for the non-risk-conferring allele (i.e. FTO-CC) (n= 49) and the other for those who had at least one copy of the obesity risk-conferring A allele (i.e. FTO-AC/AA) (n= 71).
RESULTS: Mancova analyses adjusting for age and years of education revealed the FTO-AC/AA group performed significantly worse on indices of memory (λ= 0.94, F(2, 115) = 3.58, P= 0.03, partial η(2) = 0.06). Follow-up tests revealed a significant effect for the FTO-AC/AA group, relative to the non-carrier group, on encoding (i.e. California Verbal Learning Test Total Learning) and California Verbal Learning Test long-delay free recall (P < 0.05). No such differences between FTO carriers and non-carriers emerged on tests of attention/executive function/psychomotor speed, language, or visual-spatial ability (P > 0.05 for all).
CONCLUSIONS: These findings suggest that the FTO risk allele is associated with reduced memory performance, particularly on aspects of memory encoding and delayed recall. To elucidate underlying mechanisms, these findings will need to be replicated in larger samples that utilize neuroimaging.