Moderate-to-vigorous activity may preserve cognitive function in older adults with depression, according to study data published in the Journal of Affective Disorders.
Investigators abstracted data on older adults (≥60 years) from the 2011 to 2012 and 2013 to 2014 waves of the National Health and Nutrition Examination Survey. Depressive symptoms were evaluated using the 9-item Patient Health Questionnaire; physical activity was captured with the Global Physical Activity Questionnaire. Depressive symptoms were classified in analyses as “none,” “minimal,” “mild,” “moderate,” “moderately severe,” or “severe”; physical activity was classified as “inactive,” “insufficiently active,” or “sufficiently active.” Participant scores on the Animal Fluency Test (AFT) and the Digital Symbol Substitution Test (DSST) were extracted as measures of cognitive functioning. Sociodemographic characteristics and any chronic illness diagnoses were also extracted from survey data. Multiple linear regression analyses were conducted to assess the role of physical activity on depression and cognition.
Data from 2604 older adults were included in the final analyses. Participants were of mean age 69.0 years at the time of survey administration, and the average body mass index was 29.1 kg/m2. Compared with women with none or minimal depressive symptoms, women with moderate to severe depressive symptoms had a 1.7 (95% CI, -0.5 to -2.9) point lower score on the AFT. When analyses were stratified by physical activity, however, the lower AFT test score remained only in those who were inactive. In women who were sufficiently or insufficiently active, there was no difference in AFT test performance in participants with moderate to severe depression and women with none or minimal depression. No such association was observed in men. In terms of DSST performance, women with moderate to severe depressive symptoms had a 5.4 (95% CI, -1.0 to -9.9) point lower score than women with none to minimal depression.
Men with moderate to severe depressive symptoms had a 5.6 (95% CI, -11.5 to 0.2) point lower score than their counterparts with none or minimal depression, which was borderline significant. Poorer DSST performance in participants with moderate to severe depressive symptoms persisted in inactive men (-7.2; 95% CI, -13.1 to -1.3), inactive women (-6.4; 95% CI, -11.8 to -1.1), and women who were insufficiently active (-7.3; 95% CI, -12.4 to -2.1). This effect was attenuated to null in participants engaging in sufficient physical activity.
These data suggest that physical activity may be important for preserving cognition in older adults with depression. Sufficient exercise, described as 150 minutes of moderate-to-vigorous activity per week, may protect older adults with depressive symptoms from cognitive decline in older age.
Hu L, Smith L, Imm KR, Jackson SE, Yang L. Physical activity modifies the association between depression and cognitive function in older adults. J Affect Disord. 2019;246:800-805.