Objectives
The short form or s‐allele variant of the serotonin transporter polymorphism (5‐HTTLPR), as compared with the long form or l‐allele variant, has been associated with the presence of cognitive dysfunction, and particularly memory impairment in older adults. This body of cross‐sectional work has culminated in the hypothesis that presence of the s‐allele predicts greater memory decline in older adults (1). Yet, to date, there are no longitudinal studies which have investigated this issue.
Methods/Design
Here we examine 109 community‐dwelling older adults (mean and SD of age = 70.7±8.7 years) who underwent blood draw for genotyping, cognitive, and psychological testing at baseline, 12‐month, and 24‐month follow‐up.
Results
Multilevel modeling found that s‐allele carriers (ss or ls) performed worse than ll homozygotes at baseline on delayed verbal recall. Yet, s‐allele carriers’ memory performance was stable over the two‐year follow‐up period, while l‐allele homozygotes experienced significant memory decline. l‐allele homozygote status was associated with both increased cortisol and decreased memory over time, resulting in attenuated verbal memory performance differences compared to s‐allele carriers with age.
Conclusions
Overall, our findings do not support the hypothesis that presence of the 5‐HTTLPR s‐allele is a marker for memory decline in older adults.
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