Does Body Mass Index Modify Memory, Reasoning, and Speed of Processing Training Effects in Older Adults

Body mass index predicts cognitive aging trajectories selectively for females: Evidence from the Victoria Longitudinal Study

OBJECTIVE

Elevated body weight in midlife is an established risk factor for accelerated cognitive decline, impairment, and dementia. Research examining the impact of later-life body mass index (BMI) on normal cognitive aging has produced mixed results. There is a need for longitudinal designs, replication across multiple cognitive domains, and consideration of BMI effects in the context of important moderators. The present research examined (a) BMI prediction of neuropsychological performance and decline in executive function (EF), neurocognitive speed, and memory and (b) sex stratification of BMI effects.

METHOD

Participants (n = 869; 573 females; M age = 71.75, range = 53-85 years) were older adults from the Victoria Longitudinal Study. Latent growth modeling was used to examine BMI as a predictor of level and change in three latent variables of cognition. The data were then stratified by sex to test whether BMI effects differed for females and males. We adjusted for selected medical, psychosocial, and demographic characteristics.

RESULTS

Higher BMI predicted less decline in EF, neurocognitive speed, and memory. Interestingly, when the data were stratified by sex, higher BMI predicted less neuropsychological decline across domains for females only. BMI was unrelated to cognitive aging trajectories for males.

CONCLUSIONS

We found that elevated BMI was a risk-reducing factor for cognitive decline only for females. Results may be used to enhance the precision with which intervention protocols may target specific subgroups of older adults. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Prognostic factors for change in memory test performance after memory training in healthy older adults: a systematic review and outline of statistical challenges

BACKGROUND

The goal is to investigate prognostic factors for change in memory test performance in healthy older adults and to report and discuss the different statistical procedures used for investigating this topic in the literature.

METHODS

Prognostic factors were here understood as any measures that were investigated to estimate change in memory test performance. MEDLINE, Web of Science Core Collection, CENTRAL, and PsycInfo were searched up to November 2019. Prognostic factor and prognostic factor finding studies investigating prognostic factors on verbal and non-verbal short- and long-term memory after conducting memory training in healthy older adults were included. Risk of bias was assessed using the QUIPS tool.

RESULTS

Our search yielded 12,974 results. We included 29 studies that address prognostic factors of change in memory test performance, including sociodemographic, (neuro-)psychological, genetic, and biological parameters. Studies showed high variation and methodological shortcomings with regard to the assessment, statistical evaluation, and reporting of the investigated prognostic factors. Included studies used different types of dependent variables (change scores vs. post-test scores) when defining change in memory test performance leading to contradictory results. Age was the only variable investigated throughout most of the studies, showing that older adults benefit more from training when using the change score as the dependent variable.

CONCLUSION

Overall, there is a need for adequate reporting in studies of prognostic factors for change in memory test performance. Because of inconsistencies and methodological shortcomings in the literature, conclusions regarding prognostic factors remain uncertain. As a tentative conclusion, one may say that the higher the age of the participant, the more profound the improvement in memory test performance will be after memory training.

TRIAL REGISTRATION

CRD42019127479.